D15.2: Report on the ARIADNE Linked Data Cloud

D15.2: Report on the ARIADNE Linked Data Cloud Authors: Franca Debole, CNR-ISTI Carlo Meghini, CNR-ISTI Guntram Geser , SRFG Douglas Tudhope, USW Ariadne is funded by the European Commission’s 7th Framework Programme. The$views$and$opinions$expressed$in$this$report$are$the$sole$responsibility$of$the$author(s)$and$do$not$ necessarily$reflect$the$views$of$the$European$Commission.$ ARIADNE$–$D15.2:$Report$on$the$ARIADNE$Linked$Data$Cloud,$Prepared$by$CNR-ISTI,$SRFG$and$USW$(Public)$ ! ! ! Version:$1.0$(final)$ 27th%January%2017% Authors:$ Franca%Debole%and%Carlo%Meghini,%CNR-ISTI% Guntram%Geser%,%SRFG% Douglas%Tudhope,%USW% $ $ Contributing$Partners$ $ $ $ $ $ $ % Ceri%Binding,%USW% Sara%Di%Giorgio,%MIBAC-ICCU% Achille%Felicetti%,%PIN% Dimitris%Gavrilis%,%ATHENA%RC% Philipp%Gerth,%DAI% Maria%Theodoridou,%FORTH% % Quality$review:$ Holly%Wright,%ADS% Paola%Ronzino,%PIN% ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 3! January!2017! ! Table&of&content& ! Executive&Summary&.........................................................................................................................&7! 1!Introduction&...............................................................................................................................&8! 2!Vision,&study&summaries,&and&recommendations&......................................................................&11! 2.1!Archaeological!Linked!Open!Data!–!a!vision!.............................................................................!11! 2.2!Study!summaries!and!recommendations!.................................................................................!12! 2.2.1!Linked!Open!Data:!Background!and!principles!............................................................................!12! 2.2.2!The!Linked!Open!Data!Cloud!........................................................................................................!13! 2.2.3!Adoption!of!the!Linked!Data!approach!in!archaeology!...............................................................!14! 2.2.4!Requirements!for!wider!uptake!of!the!Linked!Data!approach!....................................................!15! 2.2.5!Linked!Data!development!in!ARIADNE!........................................................................................!21! 2.2.6!ARIADNE!LOD!Cloud!.....................................................................................................................!22! 3!Linked&Open&Data:&Background&and&principles&..........................................................................&24! 3.1!LOD!–!A!brief!introduction!........................................................................................................!24! 3.2!Historical!and!current!background!...........................................................................................!25! 3.3!Linked!Data!principles!and!standards!.......................................................................................!26! 3.3.1!Linked!Data!basics!........................................................................................................................!26! 3.3.2!Linked!Open!Data!.........................................................................................................................!27! 3.3.3!Metadata!and!vocabulary!as!Linked!Data!....................................................................................!28! 3.3.4!Good!practices!for!Linked!Data!vocabularies!...............................................................................!29! 3.3.5!Metadata!for!sets!of!Linked!Data!.................................................................................................!30! 3.4!What!adopters!should!consider!first!........................................................................................!31! 3.5!Mastering!the!Linked!Data!lifecycle!.........................................................................................!32! 3.6!Brief!summary!and!recommendations!.....................................................................................!33! 4!The&Linked&Open&Data&Cloud&.....................................................................................................&35! 4.1!LOD!Cloud!figures!.....................................................................................................................!35! 4.2!(Mis-)reading!the!LOD!diagram!................................................................................................!36! 4.3!Cultural!heritage!in!the!LOD!Cloud!...........................................................................................!38! 4.4!Brief!summary!and!recommendations!.....................................................................................!41! 5!Adoption&of&the&Linked&Data&approach&in&archaeology&..............................................................&43! 5.1!Adoption!by!cultural!heritage!institutions!................................................................................!43! 5.2!Low!uptake!for!archaeological!research!data!..........................................................................!44! 5.3!The!Ancient!World!research!community!as!a!front-runner!.....................................................!45! 5.4!Brief!summary!and!recommendations!.....................................................................................!49! 6!Requirements&for&wider&uptake&of&the&Linked&Data&approach&...................................................&51! 6.1!Raise!awareness!of!Linked!Data!...............................................................................................!51! 6.1.1!Fragmentation!of!archaeological!data!.........................................................................................!51! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 4! January!2017! ! 6.1.2!Current!awareness!of!Linked!Data!...............................................................................................!52! 6.1.3!Brief!summary!and!recommendations!........................................................................................!54! 6.2!Clarify!the!benefits!and!costs!of!Linked!Data!...........................................................................!55! 6.2.1!The!notion!of!an!unfavourable!cost/benefit!ratio!.......................................................................!55! 6.2.2!Lack!of!cost/benefit!evaluation!....................................................................................................!56! 6.2.3!Collecting!examples!of!benefits!and!costs!...................................................................................!58! 6.2.4!Brief!summary!and!recommendations!........................................................................................!62! 6.3!Enable!non-IT!experts!use!Linked!Data!tools!...........................................................................!63! 6.3.1!Linked!Data!tools:!there!are!many!and!most!are!not!useable!.....................................................!63! 6.3.2!Need!of!expert!support!................................................................................................................!64! 6.3.3!The!case!of!CIDOC!CRM:!from!difficult!to!doable!........................................................................!64! 6.3.4!Progress!through!data!mapping!tools!and!templates!..................................................................!65! 6.3.5!Need!to!integrate!shared!vocabularies!into!data!recording!tools!...............................................!66! 6.3.6!Brief!summary!and!recommendations!........................................................................................!68! 6.4!Promote!Knowledge!Organization!Systems!as!Linked!Open!Data!...........................................!69! 6.4.1!Knowledge!Organization!Systems!(KOSs)!....................................................................................!69! 6.4.2!Cultural!heritage!vocabularies!in!use!...........................................................................................!70! 6.4.3!Development!of!KOSs!as!Linked!Open!Data!................................................................................!71! 6.4.4!KOSs!registries!.............................................................................................................................!74! 6.4.5!Brief!summary!and!recommendations!........................................................................................!76! 6.5!Foster!reliable!Linked!Data!for!interlinking!..............................................................................!77! 6.5.1!Current!lack!of!interlinking!..........................................................................................................!77! 6.5.2!Why!is!there!a!lack!of!interlinking?!..............................................................................................!78! 6.5.3!Need!of!reliable!Linked!Data!resources!.......................................................................................!78! 6.5.4!Foster!a!community!of!archaeological!LOD!curators!...................................................................!80! 6.5.5!Brief!summary!and!recommendations!........................................................................................!80! 6.6!Promote!Linked!Open!Data!for!research!..................................................................................!81! 6.6.1!A!Linked!Open!Data!vision!(2010)!................................................................................................!82! 6.6.2!LOD!for!research:!The!current!state!of!play!.................................................................................!82! 6.6.3!Search!vs.!research!......................................................................................................................!84! 6.6.4!Examples!of!research-oriented!Linked!Data!projects!..................................................................!85! 6.6.5!CIDOC!CRM!as!a!basis!for!research!applications!..........................................................................!86! 6.6.6!Brief!summary!and!recommendations!........................................................................................!88! 7!Linked&Data&development&in&ARIADNE&......................................................................................&89! 7.1!The!ARIADNE!catalogue!as!Linked!Open!Data!..........................................................................!89! 7.2!Work!on!vocabularies!as!Linked!Data!.......................................................................................!90! 7.2.1!Vocabularies!in!SKOS!...................................................................................................................!90! 7.2.2!Mapping!of!subject!vocabularies!.................................................................................................!92! 7.2.3!Metadata!for!vocabularies!and!mappings!in!SKOS!......................................................................!94! 7.3!What!–!Where!–!When!as!Linked!Data!.....................................................................................!94! 7.3.1!What!(subjects)!............................................................................................................................!94! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 5! January!2017! ! 7.3.2!Where!(places)!.............................................................................................................................!95! 7.3.3!When!(chronology)!......................................................................................................................!95! 7.4!Use!of!vocabularies!in!NLP!and!data!mining!............................................................................!96! 7.4.1!Natural!Language!Processing!.......................................................................................................!96! 7.4.2!Mining!of!Linked!Data!..................................................................................................................!97! 7.5!CIDOC!CRM!extensions!and!mappings!.....................................................................................!99! 7.6!Demonstrators!using!CRM-based!Linked!Data!.......................................................................!101! 7.7!Brief!summary!and!lessons!learned!.......................................................................................!104! 8!ARIADNE&LOD&Cloud&...............................................................................................................&106! 8.1!The!ARIADNE!LOD!Cloud!–!in!brief!.........................................................................................!106! 8.2!Architecture!............................................................................................................................!107! 8.3!The!Linked!Open!Data!Server!.................................................................................................!108! 8.4!The!Demonstrators!.................................................................................................................!112! 8.5!The!Mapping!and!Ontology!Server!.........................................................................................!113! 8.6!Promotion!of!external!use!......................................................................................................!115! 8.7!Brief!summary!and!lessons!learned!.......................................................................................!116! 9!References&and&relevant&other&sources&...................................................................................&118! ! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 6! January!2017! ! Acronyms&of&ARIADNE&partners& ! AIAC! Associazione!Internazionale!di!Archeologia!Classica!(Italy)! ARHEO! Arheovest!Timisoara!Association!(Romania)! ARUP-CAS! Archeologicky!ustav!AV!CR,!Praha,!v.v.i.!/!Institute!of!Archaeology!of!the!Academy! of!Sciences!(Czech!Republic)! Athena-DCU!! Athena!Research!and!Innovation!Center!in!Information!Communication!and! Knowledge!Technologies!/!Digital!Curation!Unit!(Greece)! CNR! Consiglio!Nazionale!delle!Ricerche!institutes,!CNR-ISTI!and!CNR-ITABC!(Italy)! CSIC-Incipit! Consejo!Superior!de!Investigaciones!Cientificas!/!Spanish!National!Research! Council,!Institute!of!Heritage!Sciences!(Spain)! CYI-STARC! The!Cyprus!Institute,!Science!and!Technology!in!Archaeology!Research!Center!! DAI! Deutsches!Archäologisches!Institut!(Germany)! Discovery! The!Discovery!Programme!LBG!(Ireland)! FORTH-ICS! Foundation!for!Research!and!Technology!Hellas,!Institute!of!Computer!Science! (Greece)! INRAP! Institut!National!des!Recherches!Archéologiques!Préventives!(France)! KNAW-DANS! Netherlands!Academy!of!Arts!and!Sciences,!Data!Archiving!and!Networked!Services! (Netherlands)! LeidenU! Leiden!University,!Faculty!of!Archaeology!(Netherlands)! MiBAC-ICCU! Italian!Ministry!of!Cultural!Assets!and!Activities!-!Central!Institute!for!the!Union! Catalogue!(Italy)! MNM-NOK! Magyar!Nemzeti!Múzeum,!Nemzeti!Örökségvédelmi!Központ!/!Hungarian!National! Museum,!National!Heritage!Protection!Centre!(Hungary)! NIAM-BAS! National!Institute!of!Archaeology!with!Museum!of!the!Bulgarian!Academy!of! Sciences!(Bulgaria)! ÖAW-OREA! Österreichische!Akademie!der!Wissenschaften,!Institut!für!Orientalische!und! Europäische!Archäologie!(Austria)! PIN! PIN!-!Servizi!Didattici!e!Scientifici!per!l’Università!di!Firenze!s.c.r.l.!(Italy)! SND! Swedish!National!Data!Service!(Sweden)! SRFG! Salzburg!Research!Forschungsgesellschaft!m.b.H.!(Austria)! USW! University!of!South!Wales!(United!Kingdom)! ADS-UoY! Archaeology!Data!Service,!University!of!York!(United!Kingdom)! ZRC-SAZU! Scientific!Research!Centre!of!the!Slovenian!Academy!of!Sciences!and!Arts,!Institute! of!Archaeology!(Slovenia)! ! & & ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 7! January!2017! ! & Executive&Summary& This! report! has! been!produced!within! the! ARIADNE! project! as! part! of! Work! Package!15,! “Linking! Archaeological! Data”.! This! document! is! a! deliverable! (D15.3)! of! the! ARIADNE! project! (“Advanced! Research!Infrastructure!for!Archaeological!Dataset!Networking!in!Europe”),!which!is!funded!under! the! European! Community's! Seventh! Framework! Programme.! It! presents! the! results! of! the! work! carried!out!in!Task!15.3!“ARIADNE!Linked!Data!Cloud”.!The!overall!objective!of!ARIADNE!is!to!help! making!archaeological!data!better!discoverable,!accessible!and!re-useable.!The!project!addresses!the! fragmentation!of!archaeological!data!in!Europe!and!promotes!a!culture!of!open!sharing!and!(re-)use! of!data!across! institutional,! national!and! disciplinary!boundaries!of! archaeological!research.! More! specifically,!ARIADNE!implements!an!e-infrastructure!for!data!interoperability,!sharing!and!integrated! access!via!a!data!portal.!Linked!Open!Data!can!greatly!contribute!to!these!goals.! Lessons!learned,!recommendations!and!brief!conclusions!are!included!at!the!end!of!every!section.!! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 8! January!2017! ! 1 Introduction&& Towards&a&web&of&archaeological&Linked&Open&Data&–&a&vision& The!ARIADNE!Linked!Open!Data!“cloud”!is!envisioned!as!a!web!of!semantically!interlinked!resources! of!and!for!archaeological!research.!Archaeology!is!a!multi-disciplinary!field!of!research,!hence!the! web! of! Linked! Data! initiated! by! different! projects,! including! ARIADNE,! spans! data! resources! of! various!domains!and!specialties,!for!example!history!and!geography!of!the!ancient!world,!classics,! medieval! studies,! cultural! anthropology! and! various! data! from! the! application! of! natural! science! methods!to!archaeological!research!questions!(e.g.!physical,!chemical!and!biological!sciences).! One!of!the!main!objectives!of!the!ARIADNE!project!has!been!to!provide!the!archaeological!sector! with!a!data!infrastructure!and!portal!for!discovering!and!accessing!datasets!which!are!being!shared! by! research! institutions! and! digital! archives! located! in! different! European! countries.! The! infrastructure!and!portal!are!not!stand-alone!implementations!but!serve!as!a!node!in!the!ecosystem! of! e-infrastructure! services! for! archaeology! and! various! related! disciplines,! including! other! humanities! as! well! as! social,! natural,! environmental! and! life! sciences.!To! become! such! a! node,! interoperability!with!external!services!is!required!and!can!be!implemented!based!on!the!Linked!Data! approach.!! Linked&Data&support&in&ARIADNE& WP15!supports!the!development!of!Linked!Open!Data!within!and!beyond!the!project.!The!activities! of!this!strand!of!work!concerned:!! o the!metadata!of!the!datasets!registered!in!the!ARIADNE!data!catalogue,!! o vocabularies! for! the! metadata! describing! registered! datasets! (e.g.! mapping! of! existing! vocabularies,!support!for!the!generation!of!vocabularies!in!SKOS),!! o mapping!of!datasets!to!the!core!CIDOC!CRM!and!extensions!of!the!CRM!created!in!ARIADNE,!! o demonstrators! generating! and! using! Linked! Data! (e.g.! metadata! extracted! from! unstructured! data!such!as!grey!literature,!exploration!of!CIDOC!CRM!based!data),!and! o providing!access!to!ARIADNE!Linked!Data!for!external!application!developers.! Thus! the! work! centred! on! Linked! Data! related! to! data! registration,! enabling! data! integration! via! vocabularies! and! the! CIDOC! CRM!ontology,!demonstration! of! enhanced! or! new! capabilities,! and! making!the!ARIADNE!data!catalogue!and!other!results!of!these!activities!accessible!through!a!graph! database!or!“cloud”!of!Linked!Data.! Current&level&of&LOD&adoption&in&archaeology& The!last!10!years!have!seen!substantial!progress!in!LOD!expertise,!i.e.!what!is!required!to!produce,! publish!and!interlink!LOD!from!cultural!heritage!collections!(e.g.!museum!artefact!collections).!This! expertise!has!been!acquired!mostly!through!experimental!projects,!and!only!a!few!cultural!heritage! datasets!are!effectively!interlinked!as!yet.!With!regard!to!archaeological!data!specifically,!few!Linked! Data!datasets!have!been!produced!and!hardly!any!show!up!on!the!well-known!LOD!Cloud!diagram.!In! coming!years!a!much!wider!uptake!of!the!LOD!approach!in!the!domain!is!necessary,!so!that!a!rich! web!of!data!can!emerge.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE! 9! January!2017! ! Requirements&for&a&wider&uptake& WP15! activities! took! into!account! factors! that! currently! impede! the! development! of! a! web! of! semantically! interlinked! archaeological! data.!Therefore! the! present! report! particularly! addresses! requirements! for! a! wider! uptake! of! a! Linked! Data! approach! in! archaeology.! The! study! of! these! requirements!will!be!valuable!for!many!who!have!taken!an!interest!in!Linked!Open!Data!(LOD),!would! like!an!overview!of!the!current!situation!in!cultural!heritage!and!archaeology,!and!recommendations! on!how!to!advance!the!availability!and!interlinking!of!LOD!in!this!field.! Specific!actions!are!recommended!to:!! o raise!awareness!of!Linked!Data,! o clarify!the!benefits!and!costs!of!Linked!Data,! o enable!non-IT!experts!use!Linked!Data!tools,! o promote!Knowledge!Organization!Systems!as!Linked!Open!Data,! o foster!reliable!Linked!Data!for!interlinking,! o promote!Linked!Open!Data!for!research.! Among!the!various!requirements,!the!importance!of!fostering!a!community!of!LOD!curators!who!take! care!for!proper!generation,!publication!and!interlinking!of!archaeological!datasets!and!vocabularies! were!highlighted.! Lessons&learned&in&the&development&of&LOD&within&ARIADNE& One!finding!is!the!critical!importance!of!the!subject!vocabularies,!e.g.!the!Getty!Art!and!Architecture! Thesaurus!(AAT),!combined!with!the!CIDOC!CRM!ontology!entities,!which!act!as!linking!hubs!for!the! web!of!data.!This!is!the!most!obvious!route!to!connection!with!external!LOD.!More!work!is!needed! on! the! identification! of! further! linking! hubs,! for! example! the! Period0! set! of! cultural! periods.! The! mapping!of!datasets!to!such!hubs!requires!domain!knowledge,!easy!to!use!tools,!and!guidance!for! users!who!are!carrying!out!such!work!for!the!first!time.!While!recommended!tools!are!helpful,!fully! automated! mapping! appears!unlikely!to! achive! quality!results! at!the!current!time.!There! is!much! scope!to!explore!the!utility!of!LOD!in!practice,!taking!account!of!the!objectives!and!requirements!of! different! user! communities.! There! is! still! a! way! to! go! before! advanced! uses! of! LOD! will! become! applicable!and!beneficial!in!online!research!environments;!more!effort!must!be!invested!to!make!this! happen.! In! order! to! motivate! user! organisations!to! work!with! Linked! Data,! exemplar! working! applications!are!needed!that!address!a!real!user!(scientific/research)!need.!Such!exemplars!might!be! end!user!applications!or!programmatic!interfaces!to!the!underlying!LOD.!! Building&the&ARIADNE&LOD&Cloud&–&lessons&learned& While!the!Linked!Open!Data!standards!are!essential!for!integrating!data,!the!technology!supporting! such!integration!is!still!in!its!infancy.!The!ARIADNE!LOD,!comprised!of!LOD!derived!from!the!ARIADNE! catalogue,!is!represented!by!three!demonstrators!and!various!vocabularies,!and!has!resulted!in!the! creation!of!about!32!million!RDF!triples.!While!any!relational!database!can!easily!handle!millions!of! records,! the! corresponding! volume! of! RDF! in! a! current! triple! store! can! cause! serious! efficiency! problems!as!experienced!in!the!experimentation!with!the!ARIADNE!Linked!Data!Cloud,!and!that!this! is!the!price!to!be!paid!for!interoperability.!More!robust!and!efficient!graph!databases!are!required!if! we!want!to!proceed!towards!Big!Data!as!Linked!Data.!This!is!the!first!major!lesson!learned!while! implementing!the!ARIADNE!Linked!Data!Cloud.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!16!January!2017! ! visibility! of! collections! and! creating! relations! with! various! other!information! resources.! Some! respondents! also!considered! possible!disadvantages,! e.g.! loss! of! control!over!their!own!data!or!a! decrease!in!data!quality!due!to!links!to!non-authoritative!sources.! In!the!ARIADNE!online!survey!(2013)!“Improvements!in!linked!data”,!i.e.!interlinking!of!information! based!on!Linked!Data!methods!to!enable!better!information!services,!was!considered!more!helpful! by! repository! managers! than! researchers.! Researchers! perceived! interlinking! of! information! as! important,!but!may!not!see!this!as!an!area!for!their!own!research.!Indeed,!individual!researchers!and! research!groups!should!may!not!be!thought!of!as!a!primary!focus!of!Linked!Data!initiatives.!Managers! of!digital!archives!for!the!research!community!and!institutional!repositories!are!much!more!relevant! target!groups.!Furthermore!data!managers!of!large!and!long-term!archaeological!projects!should!be! addressed!as!they!will!also!consider!required!standards!for!data!management!and!interlinking!more! thoroughly.! Recommendations& o Address!the!highly!fragmented!landscape!of!archaeological!data!and!highlight!that!Linked!Data! can!allow!dispersed!and!heterogeneous!data!resources!become!better!integrated!and!accessible.! o Consider! as! primary! target! group! of! Linked! Data! initiatives! not! individual! researchers! but! managers!of!digital!archives!and!institutional!repositories.! o Include!also!data!managers!and!IT!staff!of!large!and!long-term!archaeological!projects!as!they! will!also!consider!required!standards!for!data!management!and!interlinking!more!thoroughly.! ! Clarify&the&benefits&and&costs&of&Linked&Data& Brief&summary&& There!is!a!widespread!notion!of!an!unfavourable!ratio!of!costs!compared!to!benefits!of!employing! Semantic!Web!/!Linked!Data! standards!for!information!management,!publication! and!integration.! This! notion! should! be! removed! as! it! is! a! strong! barrier! to! a! wider! adoption! of! the! Linked! Data! approach.!! The!basic!assumption!of!Linked! Data!is! that!the!usefulness! and!value! of! data! increases! the! more! readily! it! can! combined! with! relevant! other! data.!Convincing! tangible! benefits! of! Linked! Data! materialise!if!information!providers!can!draw!on!own!and!external!data!for!enriching!services.!There! are!examples!for!such!benefits,!e.g.!in!the!museum!context,!but!not!yet!for!archaeological!research! data.!Importantly,!in!the!realm!of!research!benefits!of!Linked!Data!are!less!about!enhanced!search! services! but! research! dividends,! e.g.! discovery! of! interesting! relations! or! contradictions! between! data.! Linked!Data!projects!typically!mention!some!benefits!(e.g.!integration!of!heterogeneous!collections,! enriched!information!services),!but!very!little!is!known!about!the!costs!of!different!projects.!There!is! a!clear!need!to!document!a!number!of!reference!examples,!for!example,!what!does!it!cost!to!connect! datasets!via!shared!vocabularies!or!integrate!databases!through!mapping!them!to!CIDOC!CRM,!and! how!does!that!compare!to!perceived!benefits?!Although!vocabularies!play!a!key!role!in!Linked!Data! astonishing!little!is!also!known!about!the!costs!of!employing!various!KOSs.! Some!methods!and!tools!appear!to!have!reduced!the!cost!of!Linked!Data!generation!considerably,! OpenRefine!or!methods!to!output!data!in!RDF!from!relational!databases,!for!instance.!As!there!is!a! proliferation!of!tools!potential!Linked!Data!providers!need!expert!advice!on!what!to!use!(and!how!to! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!17!January!2017! ! use!it)!for!their!purposes!and!specific!datasets,!taking!account!also!of!existing!legacy!systems!and! standards!in!use.! Recommendations& o Proponents! of! the! Linked! Data! approach! should! address! the! widespread! notion! of! an! unfavourable! ratio! of! costs! compared! to! benefits! of! employing! Semantic! Web! /! Linked! Data! standards.!! o Major! benefits! of! Linked! Data! can! be! gained! from! integration! of! heterogeneous! collections/! databases!and!enhanced!services!through!combining!own!and!external!data.!But!examples!that! clearly!demonstrate!such!benefits!for!archaeological!data!are!needed.! o In!order!to!evaluate!the!costs,!information!about!the!cost!factors!and!drivers!should!be!collected! and!analysed.!A!good!understanding!of!the!costs!of!different!Linked!Data!projects!will!help!reduce! the!costs,!for!example!by!providing!dedicated!tools,!guidance!and!support!for!certain!tasks.!! o More!information!would!be!welcome!on!how!specific!methods!and!tools!have!allowed!institutions! reducing!the!costs!of!Linked!Data!in!projects!of!different!types!and!sizes.! o General!requirements!for!progress!are!more!domain-specific!guidance!and!reference!examples!of! good!practice.! ! Enable&non-IT&experts&use&Linked&Data&tools& Brief&summary&& Showcase! examples! of! Linked! Data! applications! in! the! field! of! cultural! heritage! (e.g.! museum! collections)!so!far!depended!heavily!on!the!support!of!experts!who!are!familiar!with!the!Linked!Data! methods! and! required! tools! (often! their! own! tools).! But! such! know-how! and! support! is! not! necessarily!available!for!the!many!cultural!heritage!and!archaeology!institutions!and!projects!across! Europe.!A!much!wider!uptake!of!Linked!Data!will!require!approaches!that!allow!non-IT!experts!(e.g.! subject!experts,!curators!of!collections,!project!data!managers)!do!most!of!the!work!with!easy!to!use! tools!and!little!training!effort.!! A!number!of!projects!have!reported!advances!in!this!direction!based!on!the!provision!of!useful!data! mapping! recipes! and! templates,! proven! tools,! and! guidance! material.! ! For! example,! the! STELLAR! Linked!Data!toolkit!has!been!employed!in!several!projects!and!appears!to!be!useable!also!by!nonexperts!with!little!training!and!additional!advice.!! Good! tutorials! and! documentation! of! projects! are! helpful,! but! the! need! for! expert! guidance! in! various!matters!of!Linked!Open!Data!is!unlikely!to!go!away.!For!example,!there!are!a!lot!of!immature,! not!tried!and!tested!software!tools!around.!Therefore!advice!of!experts!is!necessary!on!which!tools! are!really!proven!and!effective!for!certain!tasks,!and!providers!of!such!tools!should!offer!practical! tutorials!and!hands-on!training,!if!required.!Experienced!practitioners!can!also!help!projects!navigate! past!dead!ends!and!steer!project!teams!toward!best!practices.! Also!more!needs!to!be!done!with!regard!to!integrating!Linked!Data!vocabularies!in!tools!for!data! recording! in! the! field! and! laboratory.! Like! other! researchers! archaeologists! typically! show! little! enthusiasm! to! adopt! unfamiliar! standards! and! terminology,! which! is! perceived! as! difficult,! timeconsuming,!and!may!not!offer!immediate!practical!benefits.!! Proposed!tools!therefore!need!to!fit!into!normal!practices!and!hide!the!semantic!apparatus!in!the! background,! while! supporting! interoperability! when! the! data! is! being! published.! Noteworthy! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!18!January!2017! ! examples!are!the!FAIMS!mobile!data!recording!tools!and!the!RightField!tool!for!semantic!annotation! of!laboratory!spreadsheet!data.!! Recommendations! o Focus!on!approaches!that!allow!non-IT!experts!do!most!of!the!work!of!Linked!Data!generation,! publication!and!interlinking!with!little!training!effort!and!expert!support.! o Provide! useful! data! mapping! recipes! and! templates,! proven! tools! and! guidance! material! to! enable!reducing!some!of!the!training!effort!and!expert!support!which!is!still!necessary!in!Linked! Data!projects.!! o Steer!projects!towards!Linked!Data!best!practices!and!provide!advice!on!which!methods!and!tools! are!really!proven!and!effective!for!certain!data!and!tasks.! o Current!practices!are!very!much!focused!on!the!generation!of!Linked!Data!of!content!collections.! More! could! be! done! with! regard! to! integrating! Linked! Data! vocabularies! in! tools! for! data! recording!in!the!field!and!laboratory.! ! Promote&Knowledge&Organization&Systems&as&Linked&Open&Data& Brief&summary& Knowledge! Organization! Systems!(KOSs)! such! as! ontologies,! classification! systems,! thesauri! and! others!are!among!the!most!valuable!resources!of!any!domain!of!knowledge.!In!the!web!of!Linked! Data!KOSs!provide!the!conceptual!and!terminological!basis!for!consistent!interlinking!of!data!within! and!across!fields!of!knowledge,!enabling!interoperability!between!dispersed!and!heterogeneous!data! resources.!! The!RDF!family!of!specifications!provides!“languages”!for!Linked!Data!KOSs.!The!relatively!lightweight! language! Simple! Knowledge! Organization! System! (SKOS)!can! be! used! to! transform! a! thesaurus,! taxonomy! or! classification! system! to! Linked! Data.! KOSs! that! are! complex! conceptual! reference! models!(or!ontologies)!of!a!domain!of!knowledge!are!typically!expressed!in!RDF!Schema!(RDFS)!or! the!Web!Ontology!Language!(OWL).!Linked!Data!KOSs!are!machine-readable!which!allows!various! advantages.! For! example! a! SKOSified! thesaurus! employed! in! a! search! environment! can! enhance! search! &! browse! functionality! (e.g.! facetted! search! with! query! expansion),! while! Linked! Data! ontologies!can!allow!automated!reasoning!over!semantically!linked!data.! Some!years!ago!many!KOSs!were!still!made!available!as!copyrighted!manuals!or!online!lookup!pages.! Recently! open! licensing! of! KOSs! has! become! the! norm! and! ever! more! existing! KOSs! are! being! prepared!and!published!as!Linked!Open!Data!for!others!to!re-use.!Following!the!path-breaking!library! community,! the! initiative! for! KOSs! as! LOD! is! under! way! also! in! the! field! of! cultural! heritage! and! archaeology.! Some! international! and! national! KOSs! are! already! available! as! LOD,! Iconclass,! Getty! thesauri!(e.g.!Arts!&!Architecture!Thesaurus),!several!UK!cultural!heritage!vocabularies,!the!PACTOLS! thesaurus!(France,!but!multi-lingual),!and!others.! But! more! still! needs! to! be! done! for! motivating! and! enabling! owners! of! cultural! heritage! and! archaeology! KOSs! to! produce! LOD! versions! and! align! them! with! relevant! others,! for! example! mapping! proprietary! vocabulary! to! major! KOSs! of! the! domain.! Also! more! LOD! KOSs! for! research! specialities,!such!as!the!Nomisma!ontology!for!numismatics,!are!necessary.!! The!sector! of!cultural!heritage!and!archaeology! could!also! benefit!from! a!dedicated!international! registry!for!KOSs!already!available!as!LOD!or!in!preparation.!An!authoritative!registry!could!serve!as! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!19!January!2017! ! an!instrument!of!quality!assurance!and!foster!a!community!of!KOSs!developers!who!actively!curate! vocabularies.!Such!a!registry!could!also!allow!announcing!LOD!KOSs!projects!so!that!duplication!of! work!may!be!prevented!and!collaborative!efforts!promoted!(e.g!vocabulary!alignments).! Recommendations& o Foster!the!availability!of!existing!Knowledge!Organization!Systems!(KOSs)!for!open!and!effective! usage,! i.e.! openly! licensed! instead! of! copyright! protected,! machine-readable! in! addition! to! manuals!and!online!lookup!pages.! o Provide! practical! guidance!and! suggest! effective! methods! and! tools! for! the! generation,! publication!and!linking!of!KOSs!as!Linked!Open!Data!(LOD).! o Encourage! institutional! owners/curators! of! major! domain! KOSs! (e.g.! at! the! national! level)! to! make!them!available!as!LOD.!! o Promote!alignment!of!major!domain!KOSs!and!mapping!of!proprietary!vocabulary,!e.g.!simple! term!lists!or!taxonomies!as!used!by!many!organizations,!to!such!KOSs.!! o Promote!a!registry!for!domain!KOSs!that!supports!quality!assurance!and!collaboration!between! vocabulary!developers/curators.! ! Foster&reliable&Linked&Data&for&interlinking& Brief&summary!! The!core!Linked!Data!principle!arguably!is!that!publishers!should!link!their!data!to!other!datasets,! because! without! such! linking! there! is! no! “web! of! data”.! In! practice! this! principle! is! often! not! followed,! particularly! also! not! in! the! field! of! cultural! heritage! and! archaeology.! This! means! that! already!produced!Linked!Data!remains!isolated,!a!web!of!data!has!not!emerged!yet.!There!are!several! reasons!for!this!shortcoming.!Obviously!one!factor!is!that!only!few!projects!so!far!have!produced!and! exposed!archaeological!Linked!Data.!Developers!of!such!data!will!also!not!consider!popular!Linked! Data! resources! like! DBpedia/Wikipedia! as! relevant! candidates.! Moreover! there! is! the! issue! of! reliability,!that!data!one!links!to!will!remain!accessible,!which!often!they!are!not.!Surveys!found!that! many!datasets!present!problems,!for!example!SPARQL!endpoints!are!often!off-line!or!present!errors.!! With!the!increasing!number!of!Linked!Data!resources!their!quality!has!become!a!core!topic!of!the! developer! community.! Detailed! quality! schemes! and! metrics! are! being! elaborated! and! used! to! scrutinize!resources!and!suggest!improvements.!The!quality!criteria!essentially!are!about!how!users! (humans!and!machines)!can!discover,!understand!and!access!Linked!Data!resources!that!are!wellstructured,!accurate,!up-to-date!and!reliable!over!time.!Furthermore!the!resources!should!be!welldocumented,! e.g.! with! regard! to! data! provenance! and! policy/licensing.! Ideally! the! result! of! the! quality!initiative!will!be!easy!to!use!tools!that!allow!Linked!Data!curators!monitor!resources,!detect! and!fix!problems!so!that!high-quality!webs!of!data!are!being!developed!and!maintained.! The! lack! of! trustworthy!resources!in! many! quarters! of! the! “web! of! data”! makes! clear! that! a! community!of!curators!is!necessary!who!take!care!for!reliable!availability!and!interlinking!of!highquality! archaeological! LOD! datasets! and! vocabularies.! A! few! domains! already! have! such! a! community,! the! Libraries! and! Life! Sciences! domains,! for! instance.! Also! the! Ancient! World! LOD! community!around!the!Pelagios!initiative!or!the!Nomisma!community!can!be!mentioned!as!examples! of!good!practice.!It!appears!that!the!domain!of!archaeology!needs!a!LOD!task!force!and!a!number!of! projects!which!demonstrate!and!make!clear!what!is!required!for!reliable!interlinking!of!LOD.!! Recommendations& ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!20!January!2017! ! o Foster! a! community! of! LOD! curators! who! take! care! for! proper! generation,! publication! and! interlinking!of!archaeological!datasets!and!vocabularies.! o Form!a!task!force!with!the!goal!to!ensure!reliable!availability!and!interlinking!of!LOD!resources;! LOD!quality!assurance!and!monitoring!should!be!established.!! o Sponsor! a! number! of! projects! which! demonstrate! the! interlinking! and! exploitation! of! some! exemplary!archaeological!datasets!as!Linked!Open!Data.! ! Promote&Linked&Open&Data&for&research& Brief&summary& Linked!Open!Data!based!applications!that!demonstrate!considerable!advances!in!research!processes! and! outcomes! could! be! a! strong! driver! for! a! wider! uptake! of! the! LOD! approach! in! the! research! community.!Current!examples!of!Linked!Data!use!for!research!purposes!rarely!go!beyond!semantic! search! and! retrieval! of! information.! This!has! not! gone! unnoticed! by! researchers! who! expect! relevance!of!Linked!Open!Data!also!for!generating!and!validating!or!scrutinizing!knowledge!claims.!To! allow!for!such!uses!a!tighter!integration!of!discipline-specific!vocabularies!and!effective!Linked!Data! tools!and!services!for!researchers!are!required.! Expectations!of!reseach-focused!applications!of!LOD!in!the!field!of!cultural!heritage!and!archaeology! often! relate! to! the! CIDOC! CRM!as! an! integrating! framework.! The! CIDOC! CRM!is! recognised! as! a! common! and! extendable! ontology! that! allows! semantic! integration! of! distributed! datasets! and! addressing!research!questions!beyond!the!original,!local!context!of!data!generation.!Notably,!in!the! ARIADNE! project! several! extensions! of! the! CIDOC! CRM!have! been! created! or! enhanced,! e.g.! CRMarchaeo,!an!extension!for!archaeological!excavations,!and!extensions!for!scientific!observations! and!argumentation!(CRMsci!and!CRMinf).!! To!meet!expectations!such! as!automatic!reasoning!over!a!large!web!of! archaeological!data!many! more!(consistent)!conceptual!mappings!of!databases!to!the!CIDOC!CRM!would!be!necessary.!Linked! Data! applications! then! might! demonstrate! research! dividends! such! as! detecting! inconsistencies,! contradictions,! etc.! in! scientific! statements! (knowledge! claims)! or! suggesting! new,! maybe! interdisciplinary!lines!of!research!based!on!surprising!relationships!between!data.! Recommendations& o LOD!based!applications!that!enable!advances!in!archaeological!research!processes!and!outcomes! may!foster!uptake!of!the!LOD!approach!by!the!research!community.! o LOD!based!applications!for!research!will!have!to!demonstrate!advantages!over!or!other!benefits! than!already!established!forms!of!data!integration!and!exploitation.! o Develop!LOD!based!services!that!go!beyond!semantic!search!and!retrieval!of!information!and!also! support!other!research!purposes.! o Build!on!the!CIDOC!CRM!and!available!extensions!to!exploit!conceptually!integrated!LOD.! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!21!January!2017! ! 2.2.5 Linked&Data&development&in&ARIADNE& Brief&summary&& The! developmental! ARIADNE! Linked! Data! work! described! in! this! chapter! has! focused! on! the! production!of!(and!support!for)!SKOS!subject!vocabularies,!mappings!between!those!vocabularies! and!the!Art!&!Architecture!Thesaurus,!in!order!to!provide!a!multilingual!capability,!and!the!mappings! of!datasets!to!the!CIDOC-CRM.!Furthermore!three! advanced!case! studies! with! demonstrators!are! presented!that!generate!and!use!Linked!Data!based!on!the!CIDOC!CRM!and!key!subject!vocabulary! hubs:!coins,!wooden!material!and!sculptures.!! The!first!two!case!studies!involve!information!extraction!from!text!reports!in!addition!to!mapping! datasets,! while! the! third! explores! external! linking! beyond! the! immediate! ARIADNE! datasets.! Exploratory!work!on!mining!of!Linked!Data!and!NLP!techniques!are!described!but!both!are!research! areas! with! potential! for! much! further! work.! The! transformation! of! the! metadata! of! the! datasets! registered!in!the!ARIADNE!data!catalogue!to!Linked!Data!is!described!in!the!next!chapter,!as!are!the! details!of!the!ARIADNE!Linked!Data!service.!! The!demonstrators!are!still!being!finalised!at!the!time!of!this!deliverable!but!will!be!available!for! general!use!via!the!ARIADNE!Portal.!For!the!reasons!discussed!in!the!early!chapters,!the!case!studies! are!experimental!investigations!of!the!future!use!cases!that!are!afforded!by!Linked!Data!technology;! they! result! in! (working)! research! demonstrators! rather! than! actual! operational! systems.! They! illustrate!the!kinds!of!possibilities!for!cross!search!and!the!semantic!integration!of!diverse!kinds!of! datasets!and!text!reports!that!Linked!Data!and!the!related!semantic!technologies!make!possible.!! One!obvious!finding!from!the!experience!to!date!is!the!critical!importance!of!the!subject!vocabularies! (e.g.!the!AAT)!combined!with!the!CIDOC!CRM!ontology!entities,!which!act!as!linking!hubs!in!the!web! of!data.!More!work!is!needed!on!the!identification!of!further!linking!hubs!and!consequent!semantic! enrichment!of!the!Linked!Data!to!relevant!external!datasets.!One!example!of!a!potential!linking!hub! is!the!Period0!set!of!cultural!periods!which!can!be!used!by!providers!of!various!archaeological!and! other!cultural!heritage!datasets.! Necessary!for!the!widespread!uptake!of!the!Linked!Data!approach!is!the!availability!of!a!variety!of! mapping! and! alignment! software! for! different! contexts,! together! with! evaluative! studies!and! guidelines!as!to!their!use.!Beyond!that,!to!motivate!user!organisations!to!devote!scarce!resources!to! working!with!Linked!Data,!some!exemplar!working!applications!are!needed!that!address!a!real!user! (scientific/research)!need.!Such!applications!should!offer!a!user!interface!that!is!easy!and!attractive! to!work!with,!one!that!does!not!require!programming!skills!or!detailed!knowledge!of!the!underlying! data!schema!or!ontology!structure.!! It!should!not!necessarily!be!assumed!that!the!end-application!directly!operates!over!a!(Linked!Data)! triple!store.!There!are!advantages!in!doing!so!for!data!updates!and!external!connections!and!it!is!an! obvious!route.!However,!periodic!harvesting!of!Linked!Data!is!a!possibility!for!applications!that!have! reasons!to!employ!a!wider!range!of!programming!platforms.!Another!possibility!is!for!Linked!Data! providers!to!consider!exposing!programmatic!web!services!for!application!developers!(in!addition!to! a! SPARQL! endpoint),! assuming! that! an! appropriate! set! of! of! use! cases! for! the! services! can! be! identified.! Lessons&learned& o Mapping!of!datasets!to!established!domain!KOSs!(in!our!case!CIDOC!CRM,!AAT!and!others)!allows! their!integration!within!and!beyond!the!catalogue!of!a!data!portal.!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!22!January!2017! ! o State-of-the-art! linking! hubs! will! play! an! increasingly! important! role! in! the! web! of! LOD,! comprehensive!domain!thesauri!as!the!AAT!as!well!as!specialised!vocabularies!like!the!Nomisma! thesaurus.!! o The! mapping! of! datasets! to! such! hubs! requires! domain! knowledge,! easy! to! use! tools,! and! guidance! of! users! who! carry! out! such! work! for! the! first! time.! While! recommender! tools! are! helpful,!fully!automated!mapping!appears!unlikely!to!achive!quality!results!at!the!current!time.! o The!ARIADNE!portal!and!pilot!demonstrators!show!that!this!work!is!worth!the!effort.!But!there!is! still!a! way! to!go!before!advanced! uses!of!LOD!will!become!applicable!and!beneficial!in! online! research!environments;!more!effort!must!be!invested!to!make!this!happen.!! o There!is!much!scope!to!explore!the!utility!of!LOD!in!practice,!taking!account!of!the!objectives!and! requirements!of!different!user!communities.!The!best!ways!to!provide!and!employ!LOD!will!largely! depend!on!their!specific!contexts!(museum!collections,!data!archives!or!research!platforms,!for! instance),! together! with! the! anticipated! use! cases.! In! order! to! motivate! user! organisations! to! work!with! Linked! Data,! exemplar! working! applications! that! address! a! real! user! (scientific/research)!need!would!be!very!helpful.! ! 2.2.6 ARIADNE&LOD&Cloud& Brief&summary& The!ARIADNE!registry!holds!metadata!of!data!resources!from!the!content!providers.!These!metadata! are! being! collected! and! enriched! with! an! aggregator! (MORe)! and! included! in! the! ARIADNE! data! catalogue.!ARIADNE!makes!the!catalogue!and!other!data!generated!in!demonstrators!available!as! Linked!Open!Data!(LOD);!thereby!the!ARIADNE!LOD!can!become!part!of!a!web!of!Linked!Data!of! archaeological!and!related!other!information!resources.! This!work!within!ARIADNE!involved!the!use!of!a!suitable!RDF!store!and!graph!database!for!the!Linked! Data! generation! and! linking! efforts.! The! project! has! experimented! with! two! such! technologies,! Virtuoso! and! Blazegraph,! to! perform! archaeologically! relevant! SPARQL! queries! on! the! generated! Linked! Data,! and! to! allow! updates! of! datasets! using! the! SPARQL! 1.1! Graph! Store! HTTP! Protocol.! Based! on! this! preliminary! work,! a! scalable! implementation! that! can! efficiently! support! the! publication! and!use!of!the! ARIADNE! LOD! has! been!designed!and! realized!to! offer!three! different! services:!the!Linked!Open!Data!Server,!the!Demonstrators,!and!the!Mapping!and!Ontology!Server.!! The! Linked! Open! Data! Server! provides! access! to! a! large! RDF! dataset,! which! comprises! of! several! graphs!of!archaeological!datasets!and!can!be!queried!via! a!SPARQL!endpoint.!The!Demonstrators! have!been!developed!to!exemplify!the!capability!of!Linked!Data!based!item-level!data!integration!to! support!answering!archaeological!research!questions.!They!represent!three!different!subject!areas!of! archaeology:! coins,! sculptures! and! wooden! material.! For! each! a! number! of! datasets! have! been! integrated!based!on!mappings!to!the!CIDOC!CRM!(and!recent!extensions)!and!use!of!other!domain! vocabularies.!The!Mapping!and!Ontology!Server!provides!information!about!the!mappings!and!the! vocabularies!(ontologies,!thesauri)!involved!in!the!ARIADNE!LOD!Cloud.! The!current!ARIADNE!LOD!Cloud!is!just!the!initial!stage!of!an!information!space!that!is!expected!to! grow!in!terms!of!data,!vocabularies,!services!and!users.!Experiments!to!exploit!the!ARIADNE! LOD! have!just!started,!with!promising!results!as!shown!by!the!Demonstrators.!Planned!future!work!will! aim! to! proceed! with! linking! the! available! Linked! Data! to! relevant! other! datasets.! To! promote! interlinking,!the!ARIADNE!LOD!will!be!announced!via!relevant!mailing!lists,!newsletters!etc.!of!the! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!23!January!2017! ! Linked!Data!community!in!the!field!of!archaeology!and!cultural!heritage.!A!number!of!Linked!Data! developers! will!also! be! contacted! directly! to! suggest! and! discuss! interlinking! with! their! or! other! available!datasets!in!the!web!of!LOD.! Lessons&learned& While!the!Linked!Open!Data!standards!are!essential!for!integrating!data,!the!technology!supporting! such!integration!is!still!in!its!infancy.!The!ARIADNE!LOD,!comprising!of!LOD!of!the!ARIADNE!catalogue,! three! demonstrators! and! various! vocabularies! sum! up! to! about! 32! million! RDF!triples.!While! any! relational! database! can! easily! handle! millions! of! records,! the! corresponding! amount! of! RDF! in! a! current!triple!store!can!cause!serious!efficiency!problems!as!experienced!in!the!experimentation!with! the!ARIADNE!Linked!Data!Cloud.!It!is!becoming!apparent!that!this!is!the!price!to!be!paid!to!have! interoperability.! More! robust! and! efficient! graph! databases! are! required! if! we! want! to! proceed! towards!Big!Data!as!Linked!Data.!This!is!the!first!lesson!that!we!have!learned!while!implementing!the! ARIADNE!Linked!Data!Cloud.! The!second!lesson!comes!from!the!graph!data!model.!This!model!is!intrinsically!binary,!hence!makes! it!difficult!to!express!higher!rank!relations,!and!to!easily!implement!data!connection!patterns.!In!the! latter! case,! the! patterns! may! involve! data! chains! that! span! several! arcs,! and! their! definition! and! implementation!is!not!trivial.!Conversely,!correlations!between!data!items!can!be!epitomized!by!such! paths,!which!need!to!be!detected,!and!this!is!a!computationally!very!intensive!task!if!the!length!of! the!paths!go!beyond!2-3!arcs.!This!fact!has!always!been!known!from!a!theoretical!point!of!view,!but! working!with!real!data!we!could!experience!it!in!practice.! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!24!January!2017! ! 3 Linked&Open&Data:&Background&and&principles&& This! chapter! introduces! the! Linked! Open! Data! approach,! describing! the! development! of! the! approach,!the!Linked!Data!principles,!standards!and!good!practices!for!datasets!and!vocabularies.! The! chapter! also! suggests! what! adopters! of! the! Linked! Data! approach! should! consider! first,! and! describes!the!main!steps!in!the!Linked!Data!lifecycle.! 3.1 LOD&–&A&brief&introduction& Linked!Data!are!Web-based!data!that!are!machine-readable!and!semantically!interlinked!based!on! World!Wide!Web!Consortium!(W3C)! recommended! standards,! in! primis!the! Resource!Description! Framework!(RDF)!family!of!specifications!but!also!others.!Linked!Open!Data!are!such!data!resources! that!are!freely!available!under!an!open!license!(e.g.!Creative!Commons!Attribution!-!CC-BY)!or!in!the! Public!Domain.! The!Linked!Data!standards!allow!the!creation,!publication!and!linking!of!metadata!and!knowledge! organization!systems!(KOSs)!in!ways!that!make!the!semantics!(meaning)!of!data!elements!and!terms! clear!to!humans!and!machines.!Linked!Data!are!linked!semantically!based!on!explicit,!typed!relations! between!the!data!resources.! The!semantic!web!of!Linked!Data!essentially!is!about!relationships!between!information!resources! such!as!collections!of!digital!content.!The!metadata!of!digital!collections!(or!other!sets!of!data!items),! describe! different! facets! of! the!resources,! e.g.! what,! where,! when,! who,! etc.! For! such! facets! knowledge!organization!systems!(KOSs)!such!as!thesauri!provide!concepts!and!terms.!! The!W3C!recommended!Linked!Data!standards!provide!the!basis!of!a!semantic!web!infrastructure! that! facilitates! domain-independent! interoperability! of! data.!Building! on! the! standards,! domainbased!metadata!and!knowledge!models!are!needed!to!enable!interoperability!and!rich!interlinking! between!data!of!specific!domains!such!as!cultural!heritage!and!archaeological!research.!! The! requirements! for! semantic! interoperability! are! considerable.! In! the! case! of! data! sets! of! archaeological!projects,!stored!in!different!digital!archives,!the!metadata!of!the!data!packages!must! be! converted! to! Resource! Description! Framework! (RDF)! and! include! terms! of! shared! vocabulary,! which!also!must!be!available!as!Linked!Data!(e.g.!in!the!Simple!Knowledge!Organization!System!–! SKOS!format).!Data!curators!thus!need!to!become!familiar!with!new!standards!and!tools!to!generate,! publish! and! connect! Linked! Data.!But! it! does! no! mean! that! they! must! abandon! established! databases,!because!tools!are!available!to!output!RDF!data!from!existing!databases!(RDB2RDF!tools).! Building!semantic!e-infrastructure!and!services!for!a!specific!domain!requires!cooperation!between! domain! data! producers/curators,! aggregators! and! service! providers.! Cooperation! is! necessary!not! only!for!sharing!datasets!through!a!domain!portal!(i.e.!the!ARIADNE!data!portal),!but! also! to! use! common!or!aligned!vocabularies!(e.g.!ontologies,!thesauri)!for!describing!the!data!so!that!it!becomes! interoperable.!For!example,!in!ARIADNE!the!data!providers!agreed!to!map!vocabulary!which!they!use! for! their! dataset! metadata! to! the! comprehensive! and! multi-lingual! Art! &! Architecture! Thesaurus! (AAT),!which!is!available!as!Linked!Open!Data.!! ARIADNE!also!recommends!the!CIDOC!Conceptual!Reference!Model!(CRM)!as!a!common!ontology!for! data! integration!based! on! Linked! Data.! The! CIDOC! CRM!has! been! developed! specifically! for! describing!cultural!heritage!knowledge!and!data.!Archaeology!partly!overlaps!with!this!domain!as! well!as!needs!modelling!of!additional!conceptual!knowledge,!for!example,!to!describe!observations! of!an!excavation!(e.g.!stratigraphy).!The!ARIADNE!Reference!Model!comprises!the!core!CIDOC!CRM! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!25!January!2017! ! and! a! set! of! enhanced! and! new! extensions,! including! for! the! archaeological! excavation! process! (CRMarchaeo)!and!built!structures!such!as!historic!buildings!(CRMba)1.! 3.2 Historical&and¤t&background& The!basic!concept!of!Linked!Data!has!been!defined!by!Tim!Berners-Lee,!the!inventor!of!the!World! Wide!Web,!in!an!article!published!in!2006!(Berners-Lee!2006).!The!concept!helped!to!re-orientate! and!channel!the!initial!grand!vision!of!the!Semantic!Web!into!a!productive!new!avenue.!In!an!update! 2010!of!the!initial!article!on!Linked!Open!Data!Berners-Lee!aligned!it!with!the!Open!Data!movement! (Berners-Lee!2010).!! In! a! historical! perspective! it! is! worth! noting!that! Berners-Lee! since! 1998! had!addressed! various! “Design!Issues”! of!the! Semantic!Web!on!the! website!of!the!World!Wide!Web!Consortium!–!W3C! (Berners-Lee!1998-).!In!2001!the!vision!of!a!Semantic!Web!reached!a!wider!audience!with!a!highly! influential!article!in!the!Scientific!American!(Berners-Lee,!Hendler!&!Lassila!2001).!The!widely!quoted! “Semantic!Web!Statement”!of!the!dedicated!W3C!Activity!(started!in!2001)!included:!“The!Semantic! Web!is!a!vision:!the!idea!of!having!data!on!the!web!defined!and!linked!in!a!way!that!it!can!be!used!by! machines! not! just! for! display! purposes,! but! for! automation,! integration! and! reuse! of! data! across! various!applications”.!2! Previous! to! Berners-Lee’s! Linked! Data! article! (2006)! the! research! and! development! community! presented!the! Semantic! Web! vision! as! a! complex! stack! of! standards! and! technologies.! This! stack! seemed!always!“under!construction”!and!together!with!the!difficult!to!comprehend!Semantic!Web! terminology!created!the!impression!of!an!academic!activity!with!little!real!world!impact.!! The!re-branding!of!the!Semantic!Web!as!Linked!Data!and!the!moderate!definition!of!such!data!was!a! brilliant!communicative!coup.!It!signalled!a!re-orientation!which!was!welcomed!by!many!observers,! including!business-oriented!information!technology!consultants!(e.g.!PricewaterhouseCoopers!2009;! Hyland! 2010).! In! 2009,! a! paper! co-authored! by! Berners-Lee! on! “Linked! Data! –! the! story! so! far”! summarised:!“The!term!Linked!Data!refers!to!a!set!of!best!practices!for!publishing!and!connecting! structured!data!on!the!Web.!These!best!practices!have!been!adopted!by!an!increasing!number!of!data! providers!over!the!last!three!years,!leading!to!the!creation!of!a!global!data!space!containing!billions! of!assertions!-!the!Web!of!Data”!(Bizer,!Heath!&!Berners-Lee!2009).!However!the!authors!also!noted! some!issues!in!Linked!Data,!in!particular,!the!quality!and!open!licensing!of!Linked!Data!required!to! allow!for!data!integration.! In! 2010! Berners-Lee’s! request! for! Linked! Open! Data! aligned! the! Linked! Data! with!the!Open!Data! movement!(Berners-Lee!2010),!which!has!become!particularly!strong!in!the!governmental!/!public! sector.!In!this!sector!Open!Data!are!seen!as!a!means!to!ensure!trust!through!transparency!and!make! publicly!funded!information!available!(Huijboom!&!Van!den!Broek!2011;!Geiger!&!Lucke!2012)3.!In! this! context! Linked! Open! Data! are! recognized! as! just! the! right! approach! to! expose! and! connect! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 1!Description!of!the!ARIADNE!Reference!Model!and!individual!extensions!(including!reference!document,! presentation,!RDFS!encoding)!is!available!at!http://www.ariadne-infrastructure.eu/Resources/AriadneReference-Model!! 2!Since!December!2013,!the!W3C!Semantic!Web!Activity!is!subsumed!under!the!W3C!Data!Activity!which!“has!a! larger!scope;!new!or!current!Working!and!Interest!Groups!related!to!‘traditional’!Semantic!Web!technologies! are!now!part!of!that!Activity”!(http://www.w3.org/2001/sw/).!In!the!course!of!this!shift,!the!quoted!“vision”! statement!has!been!removed!(replaced!by!some!other,!rather!vague!lines).!! 3!The!international!development!of!open!governmental!data!is!tracked!and!measured!by!the!Open!Data! Barometer!project,!http://opendatabarometer.org!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!32!January!2017! ! 3.5 Mastering&the&Linked&Data&lifecycle&& The!previous!sections!present!the!principles,!standards!and!good!practices!of!Linked!Data,!but!do!not! describe!how!such!data!are!actually!generated,!published!and!interlinked.!This!study!does!not!intend!! providing!a!guidebook!for!mastering!the!so!called!“lifecycle”!of!Linked!Data,!the!different!steps!that! are!necessary!to!get!to!and!benefit!from!such!data.!In!brief,!the!main!steps!are:! o Select!a!relevant!dataset:!Chose!a!dataset!which!allows!generating!value!if!made!available!as!RDF! data!and!linked!to!other!LOD,!including!linking!of!the!dataset!by!others.!The!publisher!should!of! course!be!able!to!provide!the!data!under!an!open!license!or!place!it!in!the!public!domain.! o Clean!and!prepare!the!source!data:!Bring!the!source!data!in!a!shape!that!it!is!easy!to!manipulate! and! convert! to! RDF,! addressing! issues! of! data! quality! such! as! missing! values,! invalid! values,! duplicate!records,!etc.!The!OpenRefine23!tool!is!recommended!for!this!task.!! o Design!the!URIs!of!the!data!items:!Follow!suggested!good!practice!for!designing!the!structure!of! the!URIs!(e.g.!W3C!2008;!ISA!2012).! o Define!the!target!data!model:!Re-use!an!existing!model!that!is!being!used!in!the!domain!(e.g.! CIDOC!CRM!for!cultural!heritage!data)!or!create!one!re-using!concepts!from!widely!employed! vocabularies;!re-use!will!aid!data!interoperability!and!decrease!development!effort/costs.! o Transform!the!data!to!RDF:!In!the!transformation!the!source!data!(e.g.!data!tables)!are!converted! to!a!set!of!RDF!statements!(graph-based!representation)!according!to!the!defined!target!model.! Many!tools!are!available!that!allow!transformation!of!almost!any!data!format!and!database!(e.g.! CSV,!Excel,!relational!databases)!to!RDF.24!! o Store!and!publish!the!RDF!data:!The!generated!RDF!data!is!typically!stored!in!an!RDF!database! (triple!store)!where!it!can!be!accessed!via!a!web!server!or!queried!at!an!SPARQL!endpoint;!the! data! is! also! often! published! as! a! so! called! “RDF! dump”! (a! RDF!dataset! made! available! for! download).! o Link!to!other!RDF!data!on!the!Web:!According!to!the!Linked!Data!principles!publishers!should!link! to!other!datasets!to!create!an!enriched!web!of!Linked!Data.!Therefore!relevant!linking!targets! need!to!be!identified!which!can!add!value!(i.e.!where!relationships!exist!between!data)!and!are! well!maintained.!Publishers!may!be!aware!of!such!datasets!in!their!domain!or!search!existing! registries!(e.g.!DataHub)!to!identify!relevant!datasets.!If!there!is!a!relevant!dataset,!the!publisher! must!decide!which!properties!from!established!domain!or!general!Linked!Data!vocabularies!to! use!for!the!linking.!! o Describe,!register!and!promote!the!dataset:!The!publisher!of!a!set!of!Linked!Data!should!describe! the! dataset! with! metadata!(including! provenance,! licensing,! technical! and! other! descriptive! information)!which!can!be!attached!to!the!dataset.!It!is!also!good!practice!to!register!the!dataset! in! a! domain! data! catalogue! and! general! registries! such! as! the! DataHub.!Furthermore! the! publisher! should! announce! the! dataset! via! relevant! mailing! lists,! newsletters!etc.! and! invite! others!to!consider!linking!to!the!dataset.! There! are! many! introductory! and! advanced! level! guides! available!that! describe! how! to! generate,! publish,!link!and!use!Linked!Data:!As!introductory!level!guides!Bauer!&!Kaltenböck!(2012),!Hyland!&! Villazón-Terrazas!(2011)!and!W3C!(2014)!can!be!suggested.!Advanced!“cookbooks”!are!the!EUCLID! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 23!OpenRefine,!http://openrefine.org!! 24!W3C!wiki:!Converter!to!RDF,!http://www.w3.org/wiki/ConverterToRdf!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!33!January!2017! ! curriculum25,!Heath!&!Bizer!(2011),!!Morgan!et!al.!(2014);!Ngonga!Ngomo!et!al.!(2014),!van!Hooland! &!Verborgh!(2014)!and!Wood!et!al.!(2014).! Concerning!useful!tools!such!as!RDF!converters,!Linked!Data!editors,!RDF!databases,!etc.!the!W3C! wiki!provides!an!extensive!tool!directory26.!Some!projects!describe!selected!tools!they!recommend! for!different!tasks!of!the!Linked!Data!lifecycle,!for!example,!the!projects!LATC!(various!tools)27!and! LOD2!(mainly!tools!of!the!project!partners)28.!But!adopters!of!the!Linked!Data!approach!should!seek! additional!expert!advice!on!which!tools!are!proven!and!effective!for!their!data!and!certain!tasks.!! 3.6 Brief&summary&and&recommendations& Brief&summary& The!term!Linked!Data!refers!to!principles,!standards!and!tools!for!the!generation,!publication!and! and!linking!of!structured!data!based!on!the!W3C!Resource!Description!Framework!(RDF)!family!of! specifications.!! The! basic! concept! of! Linked! Data! has! been! defined! by! Tim! Berners-Lee! in! an! article! published! in! 2006.!This!concept!helped!to!re-orientate!and!channel!the!initial!grand!vision!of!the!Semantic!Web! into!a!productive!new!avenue.!Previously!the!research!and!development!community!presented!the! Semantic!Web!vision!as!a!complex!stack!of!standards!and!technologies.!This!stack!seemed!always! “under! construction”! and! together! with! the! difficult! to! comprehend! Semantic! Web! terminology! created!the!impression!of!an!academic!activity!with!little!real!world!impact.!! In! 2010! Berners-Lee’s! request! for! Linked! Open!Data! aligned! the! Linked! Data! with! the! Open! Data! movement.!Since!then!the!quest!for!Linked!Open!Data!(LOD)!has!become!particularly!strong!in!the! governmental!/!public!sector!as!well!as!initiatives!for!cultural!and!scientific!LOD.! The!Linked!Data!principles!include!that!a!data!publisher!should!make!the!data!resources!accessible! on!the!Web!via!HTTP!URIs!(Uniform!Resource!Identifiers),!which!uniquely!identify!the!resources,!and! use!RDF!to!specify!properties!of!resources!and!of!relations!between!resources.!In!order!to!be!Linked! Data!proper,!the!publishers!should!also!link!to!URI-identified!resources!of!other!providers,!hence!add! to!the!“web!of!data”!and!enable!users!to!discover!related!information.!And!to!be!Linked!Open!Data! the!publisher!must!provide!the!data!under!an!open!license!(e.g.!Creative!Commons!Attribution![CCBY]!or!release!it!into!the!Public!Domain).! The!Linked!Data!approach!allows!opening!up!“data!silos”!to!the!Web,!interlink!otherwise!isolated! data!resources,!and!enable!re-use!of!the!interoperable!data!for!various!purposes.!The!landscape!of! archaeological! data! is! highly! fragmented.! Therefore! Linked! Data! are! seen! as! a! way! to! interlink! dispersed!and!heterogeneous!archaeological!data!and,!based!on!the!interlinking,!enable!discovery,! access!to!and!re-use!of!the!data.!! Building!semantic!e-infrastructure!and!services!for!a!specific!domain!such!as!archaeology!requires! cooperation!between! domain! data! producers/curators,! aggregators! and! service! providers.! Cooperation!is!necessary!not!only!for!sharing!datasets!through!a!domain!portal!(i.e.!the!ARIADNE! data!portal),!but!also!to!use!common!or!aligned!vocabularies!(e.g.!ontologies,!thesauri)!for!describing! the!data!so!that!it!becomes!interoperable.!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 25!EUCLID!-!Educational!Curriculum!for!the!Usage!of!Linked!Data,!http://euclid-project.eu!! 26!W3C!wiki:!Tools,!http://www.w3.org/2001/sw/wiki/Tools!! 27!LATC!-!LOD!Around!The!Clock!(EU,!FP7-ICT,!9/2010-8/2012),!http://latc-project.eu!! 28!LOD2!-!Creating!Knowledge!out!of!Interlinked!Data!(EU,!FP7-ICT,!9/2010-8/2014),!http://lod2.eu!!!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!34!January!2017! ! In! addition! to! the! basic! Linked! Data! principles!there! are! also! specific! recommendations! for! vocabularies.! Particularly! important! is! re-using! or! extending! wherever! possible! established! vocabularies!before!creating!a!new!one.!The!rationale!for!re-use!is!that!different!resources!on!the! web! of! Linked! Data! which! are! described! with! the! same! or! mapped! vocabulary! terms! become! interlinked.! This! makes! it! easier! for! applications! to! identify,! process! and! integrate! Linked! Data.! Moreover,!re-use!and!extension!of!existing!vocabularies!can!lower!vocabulary!development!costs.!! It!is!also!recommended!to!provide!metadata!for!Linked!Data!of!datasets!as!well!as!vocabularies.!The! Vocabulary!of!Interlinked!Datasets!(VoiD)!is!often!being!used!for!providing!such!metadata.!It!is!also! good!practice!to!register!sets!of!Linked!Data!in!a!domain!data!catalogue!and/or!general!registries! such!as!the!DataHub.!Furthermore!the!publisher!should!announce!the!dataset!via!relevant!mailing! lists,!newsletters!etc.!and!invite!others!to!consider!linking!to!the!dataset.! Linked! Data! should! not! be! published! “just! in! case”.! Rather! publishers! should! consider! the! re-use! potential! and! intended! or! possible! users! of! their! data.! As! Linked! Data! consumers! they! need! to! address! the! question! of! which! data! of! others! they! could! link! to.! These! questions! make! clear! the! importance! of! joint! initiatives! for! providing! and! interlinking! datasets! of! certain! domains!such! as! archaeology.!! Recommendations& o Use!the!Linked!Data!approach!to!generate!semantically!enhanced!and!linked!archaeological!data! resources.!! o Participate! in! joint! initiatives! for! providing! and! interlinking! archaeological! datasets! as! Linked! Open!Data.! o Choose! datasets! which! allow! generating! value! if! made! openly! available! as! Linked! Data! and! connected!with!other!data,!including!linking!of!the!datasets!by!others.!! o Re-use!existing!Linked!Data!vocabularies!wherever!possible!in!order!to!enable!interoperability.! o Describe! the! Linked! Data! with! metadata,! including! provenance,! licensing,! technical! and! other! descriptive!information.!! o Register!the!dataset!in!a!domain!data!catalogue!and/or!general!registries!such!as!the!DataHub.! Also!announce!the!dataset!via!relevant!mailing!lists,!newsletters!etc.!and!invite!others!to!consider! linking!to!the!dataset.! ! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!35!January!2017! ! 4 The&Linked&Open&Data&Cloud& This!chapter!describes!what!has!been!termed!the!LOD!Cloud!and!is!generally!illustrated!with!the!LOD! Cloud! diagram! of! interlinked! datasets.! Some! available! figures!for!the! state! of! the! LOD! Cloud! are! presented! and! also! some! issues! highlighted.! Furthermore! an! overview! of! cultural! heritage! LOD! present!on!the!LOD!Cloud!diagram!and!other!known!cultural!heritage!LOD,!including!archaeological! LOD,!is!being!given.! 4.1 LOD&Cloud&figures& The!Linked!Open!Data!(LOD)!Cloud!is!formed!by!datasets!that!are!openly!available!on!the!Web!in! Linked!Data!formats!and!contain!links!pointing!at!other!such!datasets.!The!latest!LOD!Cloud!figures! and!visualization!have!been!published!online!in!August!2014!(Schmachtenberg!et!al.!2014a![statistics! online],!2014b![paper]).!They!are!based!on!information!collected!through!a!crawl!of!the!Linked!Data! web!in!April!2014.!The!crawl!found!1014!datasets!of!which!569!(56%)!linked!to!at!least!one!other! dataset;!the!569!datasets!were!connected!by!in!total!2909!link-sets.!The!remaining!datasets!were! only!targets!of!RDF!links,!and!therefore!at!the!periphery!of!the!“cloud”,!or!they!were!isolated.!Of!the! 569!core!LOD!Cloud!datasets!374!were!registered!in!the!DataHub.29!The!latest!comparable!figures!to! the! ones! reported! by! Schmachtenberg! et! al.! (2014a/b)! are! based! on! the! DataHub! metadata! of! datasets!from!September!2011!(Jentzsch!et!al.!2011)30.!! Below!we!summarize!some!results!of!Schmachtenberg!et!al.!(2014a!and!2014b,!of!which!the!latter! compares!the!figures!of!2011!and!2014)!which!give!an!impression!of!the!adoption!of!the!Linked!Data! principles:!! o Increase!in!datasets:!There!has!been!a!substantial!increase!in!identified!datasets:!2011:!294!LD! datasets!registered!in!the!DataHub;!2014:!1014!datasets!identified!through!a!crawl!of!the!web!of! Linked!Data.!With!530!datasets!the!largest!group!in!2014!was!the!newly!introduced!category!of! social! web/networking.! These! datasets! describe! people! profiles! and! social! relations! amongst! people.!Among!the!established!categories!three!showed!a!large!growth!in!number!of!dataset,! Government! (2011:! 49;! 2014:! 183),! Life! Sciences! (2011:! 41;! 2014:! 83)! and! User-generated! content!(2011:!20;!2014:!48).!! o Linking!of!datasets:!445!(43.89%)!of!the!1014!datasets!did!not!set!any!out-gowing!RDF!links,!176! (17.36%)! linked! to!one! other! dataset,! 106! (10.45%)! to! two!datasets,! 127! (12.52%)! to! 3-5! datasets,!81!(7.99%)!to!6-10!datasets,!and!79!(7.79%)!even!to!more!than!10!datasets.! o A!less!centralized!LOD!Cloud:!In!2014!the!web!of!linked!data!appeared!to!be!less!centralized.!In! 2011!the!cross-domain!Linked!Data!resource!DBpedia.org!clearly!occupied!the!centre!of!the!LOD! Cloud.!In!2014!also!GeoNames!was!used!widely!and!there!were!some!category-specific!linking! hubs!(e.g.!data.gov.uk!in!the!category!Goverment).!Most!interconnected!were!resources!of!the! category!Publications!(e.g.!RKB!Explorer!datasets)!and!of!the!category!Life!Sciences!(e.g.!Bio2RDF! datasets).! o Use! of! vocabularies:!The! 2014! survey! discovered! in! total! 649! vocabularies.! 271! vocabularies! (41.76%)! were! “non-proprietary”,! defined! as! used! by! at! least! two! datasets.!Among! these! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 29!DataHub!(Open!Knowledge!Foundation),!http://datahub.io!! 30!State!of!the!LOD!Cloud,!19/09/2011,!http://lod-cloud.net/state/!!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!36!January!2017! ! vocabularies,!RDF!and!RDFS!aside,!the!most!used!were!FOAF31!(701!datasets!used!it)!and!Dublin! Core32!(568! datasets!used! it).! A! special! analysis! showed! that! among! the! 378! “proprietary”! vocabularies! (defined! as! used! by! only! one! dataset)!only! 19.25%! were!fully! and! 8%! partially! dereferencable;! 72.75%! had! term! URIs! which! were! not!dereferencable! at! all.!One! or! more! proprietary!vocabularies!were!used!by!241!datasets!(23.17%!of!the!total).! o Metadata!for!sets!of!Linked!Data:!For!35.77%!of!all!sets!of!Linked!Data!in!2014!machine-readable! provenance! and! other! metadata!were! provided! (most!often! in! Dublin! Core,! DCTerms!or! MetaVocab),! about! the! same! percentage! than! in! 2011! (36.63%).! Only! about! 8%! provided! machine-readable!licensing!information,!mostly!dc:license/dc:rights!and!cc:license.!Hence!lack!of! metadata!for!sets!of!Linked!Data!remains!an!issue.! 4.2 &(Mis-)reading&the&LOD&diagram& In!the!years!2007-2011!a!diagram!of!the!LOD!Cloud!has!been!produced!based!on!datasets!registered! in! the! DataHub.! The! latest! version! of! the! diagram! has! been! published! in! August! 201433!and! in! addition!to!the!DataHub!information!uses!the!results!of!a!crawl!of!the!Linked!Data!Web!in!April!2014! (Schmachtenberg! et! al.! 2014a/b,! as! summarized! above).! The! LOD! Cloud! diagram! has! grown! enormously,!too!large!to!present!it!here.! The!criteria!for!including!a!dataset!in!the!LOD!Cloud!diagram!are34:!! o There!must!be!resolvable!http://!(or!https://)!URIs.! o They!must!resolve,!with!or!without!content!negotiation,!to!RDF!data!in!one!of!the!popular!RDF! formats!(RDFa,!RDF/XML,!Turtle,!N-Triples).! o The!dataset!must!contain!at!least!1000!triples.! o The!dataset!must!be!connected!via!RDF!links!to!at!least!one!other!dataset!in!the!diagram,!by! using!URIs!from!that!dataset!or!vice!versa;!at!least!50!links!are!required.! o Access! of! the! entire! dataset! must! be! possible! via! RDF! crawling,! an! RDF! dump! or! a! SPARQL! endpoint.! The!LOD!Cloud!diagrams!that!since!2007!have!been!produced!based!on!these!criteria!showed!some! linking!hubs,!but!in!2014!there!still!were!many!rather!isolated!datasets!(e.g.!linked!to!only!one!other! Linked! Data! resource).!Yet! the! LOD! Cloud! diagrams! have! often! been!misleadingly! referenced! as! presenting!a!compact!“web!of!data”!or!“a!huge!web-scale!RDF!graph”!(cf.!the!critique!by!Hogan!&! Gutierrez!2014).!Also!the!researchers!who!published!the!latest!figures!on!the!LOD!Cloud!state:!“By! setting!RDF!links,!data!providers!connect!their!datasets!into!a!single!global!data!graph!which!can!be! navigated! by! applications!and! enables! the! discovery! of! additional! data! by! following! RDF! links”! (Schmachtenberg!et!al.!2014a).!! What!must!be!added!is!that!the!“single!global!data!graph”!is!patchy!(as!described!above)!and!that! relevant! applications! for! end-users! are! hardly! available.! There! are! Linked! Data! browsers35!which,! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 31!FOAF!-!Friend-of-a-Friend!(defines!terms!for!describing!persons,!their!activities!and!their!relations!to!other! people!and!object),!http://xmlns.com/foaf/spec/! 32!Dublin!Core!Metadata!Initiative!(DCMI)!Metadata!Terms,!http://dublincore.org/documents/dcmi-terms/!! 33!The!Linking!Open!Data!cloud!diagram!2014,!by!M.!Schmachtenberg,!C.!Bizer,!A.!Jentzsch!and!R.!Cyganiak,! available!at:!http://lod-cloud.net!! 34!cf.!The!Linking!Open!Data!cloud!diagram,!http://lod-cloud.net! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!37!January!2017! ! however,! seem! not! to! be! in! wider! use,! arguably! because! of! a! lack! of! interlinked! data!that! are! relevant!for!user!communities.!Research!oriented!developers!have!created!search!engines!based!on! crawled! and! semantic! Web! Data! (e.g.!Sindice! [service! ended! in! 2014],! Swoogle,! Watson).!These! engines!are!of!little!use!for!non-experts.!They!serve!as!research!tool!to!better!understand!the!Linked! Data! landscape.! Research! based! on! crawled! Web! data! has! become! a! specialty! and! is! conducted! around!resources!such!as!the!Common!Crawl36.! The!LOD!Cloud!is!not!a!single!entity!but!represents!datasets!of!different!providers!that!are!made! available! in! different! ways! (e.g.!LD! server,! SPARQL! endpoint,! RDF! dump)!and! often! with! low! reliability.! For! example,! Buil-Aranda! et! al.! (2013)! found! that! of! 427! public! SPARQL! endpoints! registered! in! the! DataHub! the! providers! of! only! one-third! gave! descriptive! metadata.! Half! of! the! endpoints! were! off-line! and! only! one! third! was! available! more! than! 99%! of! the! time! during! a! monitoring!of!27!months;!the!support!of!SPARQL!features!and!performance!for!generic!queries!was! varied.!! Public!SPARQL!endpoints!could!form!a!distributed!infrastructure!for!federated!queries37!of!relevant! data!of!different!sources!(Rakhmawati!et!al.!2013).!Thereby!views!across!the!different!datasets!could! be!provided,!allowing!researchers!to!explore!the!data.!But!this!depends!on!reliable!maintenance!of! the!datasets!and!SPARQL!endpoints!by!the!service!providers.!Instead!of!querying!the!“single!global! graph”! or! just! a! number! of! LD! datasets,! the! typical! approach! is! to! pull! the! data! into! one! data! repository! and! run! queries! over! this! database.!This! approach! is! impractical! for! any! but! a! small! number!of!datasets!(or!datasets!of! a!small!size),! especially! if! only! some! interlinking! between! the! datasets!is!of!interest.!! For! intelligent! searching,! question! answering! and! reasoning! over! Linked! Data! much!more! is! necessary!than!providing!SPARL!endpoints!or!pulling!a!number!of!datasets!into!one!graph!database.! One!approach!is!“reason-able!views”!of!Linked!Data!which!has!been!developed!by!researchers!of! Ontotext!and!demonstrated!with!the!FactForge!service38!(Kiryakov!et!al.!2009;!Damova!2010;!Simov! &! Kiryakov! 2015).! A! reason-able! view! is! constructed! by! assembling! different! datasets! and! vocabularies!into!a!compound!set!of!Linked!Data,!produce!mappings!between!instance!data!of!the! datasets,! and! create! a! single! ontology! for! querying! the! compound! dataset! using! SPARQL.!The! ontology!is!created!based!on!mappings!between!the!vocabularies!and/or!an!upper-level!ontology,!in! the!case!of!FactForge:!PROTON39.!Damova!&!Dannells!(2011)!illustrate!the!approach!with!a!“museum! reason-able!view”!including!mappings!between!CIDOC!CRM!and!PROTON,!CIDOC!CRM!and!Swedish! Open!Cultural!Heritage!(K-samsök)40,!and!information!of!the!Gothenburg!City!Museum!transformed! to!RDF.!Also!existing!mappings!of!DBPedia!and!GeoNames!to!PROTON!were!included.!A!reason-able! view!provides!a!controlled!environment!of!integrated!datasets!to!exploit!existing!and!newly!created! sets!of!Linked!Data,!reduce!development!costs!and!risks!of!unreliable!datasets.! There!is!no!central!management!of!LOD!Cloud,!the!assumed!“huge!web-scale!RDF!graph”,!but!(some)! areas!for!which!a!community!of!developers!produces!and!interlinks!relevant!resources!and!creates! applications!for!the!purposes!of!the!intended!end-users.!In!such!cases!network!effects!in!the!web!of! Linked!Data!are!being!achieved.!Such!effects!do!not!result!automatically!from!merely!putting!more! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 35!LOD!Browser!Switch!(offers!a!set!of!browsers),!http://browse.semanticweb.org!! 36!Common!Crawl,!http://commoncrawl.org!! 37!W3C!(2013)!Recommendation:!SPARQL!1.1!Federated!Query,!21!March!2013,! http://www.w3.org/TR/sparql11-federated-query/!! 38!Ontotext:!FactForge,!http://ontotext.com/factforge-links/!! 39!Ontotext:!PROTON,!http://ontotext.com/products/proton/!! 40!Swedish!Open!Cultural!Heritage!(K-samsök):!http://www.ksamsok.se/in-english/!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!38!January!2017! ! datasets!into!the!LOD!cloud,!actual!interlinking!is!required!to!generate!a!web!of!Linked!Data.!One! example!of!effective!linking!is!the!Linked!Data!community!of!the!bio-medical!and!life!sciences.!In!this! area! the! Bio2RDF41!project! has! created! 35! Linked! Data! sets! of! existing! databases! and! interlinked! some!of!them.!Another!well-curated!area!is!Linked!Data!of!the!library!community.!Cultural!heritage! or! archaeology! is! not! yet! an! area! of! densly! interlinked! information.! So! far! a!community! of! cooperating!LOD!producers,!curators!and!integrators!has!not!emerged.!! 4.3 Cultural&heritage&in&the&LOD&Cloud&& The!latest!LOD!Cloud!diagram!(August!2014)!provides!an!indicator!for!the!state!of!cultural!heritage! Linked!Data.!So!far!only!few!cultural!heritage!LD!datasets!show!up!on!the!diagram,!and!they!do!not! form!a!closely!linked!web!of!LD.!None!of!the!datasets!concerns!archaeology!specifically.!Some!more! cultural!heritage!LD!sets!exist,!also!a!few!archaeological!datasets.!But!they!did!not!conform!to!the! criteria!for!being!included!in!the!LOD!Cloud!diagram,!e.g.!the!requirement!of!being!connected!via! RDF!links!with!at!least!one!other!compliant!dataset!(see!section!above).!! Below!we!first!list!the!cultural!heritage!datasets!which!conform!to!the!criteria,!not!including!datsets! of! the! library! sector! (e.g.! Bibliothèque! nationale! de! France! [data.bnf.fr]! or! Deutsche! Nationalbibliothek![DNB]):!! o Europeana!LOD:!mentioned!in!the!first!place!because!it!is!the!largest!cultural!heritage!LD!dataset! (20!million!records)!and!comprises!of!records!of!museums,!archives!and!libraries!across!Europe42.!! o Swedish! Open! Cultural! Heritage!(K-samsök):!a! web! service! that! harvests! metadata! from! the! databases!of!cultural!heritage!organisations!in!Sweden!and!allows!creating!LD!based!information! services43.!! o Archives! Hub! Linked! Data:! the! Archives! Hub44!aggregates! and! allows! searching!across! descriptions!of!archival!collections!held!at!over!250!institutions!in!the!UK!(a!search!of!the!portal! for! “archaeology”! produces! over! 1000! hits).! Linked! Data! of! a! sub-set! of! the! aggregated! descriptions!has!been!produced!by!the!LOCAH!project!(2010-2011)45.! o British! Museum! -! Semantic! Web! Collection! Online:! provides! Linked! Data! access! to! the! same! collection! records! as! the! Museum’s! web! presented! Collection! Online;! the! data! has! also! been! organised!using!the!CIDOC!CRM46.! o Amsterdam! Museum:! has! been! the! first! museum! in! the! Netherlands! to! convert! its! complete! museum!collection!database!(over!70,000!records)!to!RDF;!the!data!includes!links!to!two!Getty! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 41!Bio2RDF:!Linked!Data!for!the!Life!Sciences,!http://bio2rdf.org!! 42!Europeana!Linked!Data,!http://labs.europeana.eu/api/linked-open-data/introduction/;!a!search!on!the! Europeana!website!for!“archaeology”!shows!that!the!providers!of!most!related!content!are!the!Swedish! National!Heritage!Board!(812,971!items)!and!the!UK!Portable!Antiquities!Scheme!(236,627).!ARIADNE! partners!are!also!present:!German!Archaeological!Institute!/!ARACHNE!(183,683!items),!Archaeology!Data! Service,!UK!(34,197)!and!Data!Archiving!and!Networked!Services,!Netherlands!(6456).! 43!Swedish!Open!Cultural!Heritage!(K-samsök):!http://www.ksamsok.se/in-english/;!see!also:!DataHub,! http://datahub.io/dataset/swedish-open-cultural-heritage! 44!Archives!Hub,!http://archiveshub.ac.uk! 45!Archives!Hub!–!LOCAH,!http://data.archiveshub.ac.uk!! 46!British!Museum!-!Semantic!Web!Collection!Online,!http://collection.britishmuseum.org! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!39!January!2017! ! thesauri! (AATNed! [Dutch! version]! and! ULAN),! GeoNames,! and! DBPedia! pages! (De! Boer! et! al.! 2012!and!2013)47.! o Art!&!Architecture!Thesaurus!(AAT)!of!the!Getty!Research!Institute:!The!only!cultural!heritage! KOS! on! the! 2014! LOD! diagram;!meanwhile! two! other! Getty! KOSs! have! become! available:! Thesaurus! of! Geographic! Names! (TGN)!and! Union! List! of! Artist! Names! (ULAN);! the! Cultural! Objects!Name!Authority!(CONA)!was!expected!to!follow!in!Fall!2015!but!seems!to!require!more! effort!than!expected48.! The!second!list!below!presents!further!cultural!heritage!and!archaeological!datasets!in!Linked!Data! formats! that!are! registered! in! the! DataHub! or! of! which! we! know! from! searching! various! other! sources.! The! list! is! certainly! not! comprehensive,!because! there! have!been! quite! some!cultural! heritage!projects!that!trialled!the!Linked!Data!approach,!however!the!whereabouts!of!the!created! Linked!Data!are!often!unclear.!The!Linked!Data!resources!listed!below!are!roughly!ordered!according! to!their!relevance!in!the!context!of!our!study:!! o Archaeology! Data! Service!(ADS):!ADS! Linked! Open! Data! initially! has! been! produced! in! the! STELLAR!project!by!converting!databases!and!CSV!files!to!RDF,!using!the!CRM-EH!ontology;!this! RDF!data!is!available!from!a!SPARQL!endpoint49.!According!to!their!annual!report!2014/2015!ADS! now!also!have!LOD!of!deposited!project!archives,!including!the!projects!Roman!Amphora50!and! Colonisation!of!Britain!(see!Cripps!2014!for!background);!the!number!of!LOD!triples!in!2015!was! 2,531,302,!up!from!680,500!in!the!previous!reporting!period!(ADS!2015:!26).!Notably,!ADS!also! consume! LOD! from! external! sources! to! populate! own! metadata! (e.g.! Ordnance! Survey! geographic!data51).! o Data! Archiving! and! Networked! Services!(DANS):!DANSlabs! has! produced! LOD! of! metadata! records!of!more!than!25,000!data!sets!stored!in!the!DANS-EASY!digital!archive,!which!includes! the!E-Depot!for!Dutch!Archaeology;!this!was!done!2013!in!a!demonstration!project,!but!the!LOD! (with!little!cross-linking)!is!accessible!via!their!SPARQL!endpoint!under!an!Open!Data!Commons! license52.! o CLAROS! -! The! World! of! Art! on! the! Semantic! Web:!the! data! of! this! international! collaboration! comes!from!major!Classics!collections,!including!from!ARIADNE!partner!DAI;!the!data!has!been! prepared!for!a!search!portal!based!on!CIDOC!CRM!modelling;!the!data!service!is!maintained!by! the!University!of!Oxford’s!e-Research!Centre!and!offers!a!SPARQL!endpoint53.! o Cultura!Italia:!provides!metadata!of!a!number!of!Italian!heritage!institutions;!offers!a!SPARQL! endpoint!for!the!metadata;!also!the!PICO!thesaurus!is!available!for!download54.!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 47!Amsterdam!Museum!in!Europeana!Data!Model!RDF,!http://semanticweb.cs.vu.nl/lod/am;!see!also:!DataHub,! http://datahub.io/dataset/amsterdam-museum-as-edm-lod!! 48!Getty!Vocabularies!LOD,!http://vocab.getty.edu! 49!ADS!Linked!Open!Data,!http://data.archaeologydataservice.ac.uk;!STELLAR!project,! http://archaeologydataservice.ac.uk/research/stellar/! 50!Roman!Amphorae:!a!digital!resource!(University!of!Southampton,!2005;!updated!2014),! http://archaeologydataservice.ac.uk/archives/view/amphora_ahrb_2005/!! 51!Ordnance!Survey!(UK),!http://data.ordnancesurvey.co.uk!! 52!DANSlabs:!EASY!Metadata!as!Linked!Open!Data!Demo,!http://dans-labs.github.io/easy-lod/! 53!CLAROS:!Data,!http://data.clarosnet.org!! 54!Cultura!Italia:!Dati,!http://dati.culturaitalia.it!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!40!January!2017! ! o English! Heritage! Places:!contains! metadata! for! about! 400,000! nationally! important! places! as! recorded!by!English!Heritage55;!also!seven!English!Heritage!and!other!UK!thesauri!are!registered! in!the!DataHub,!but!for!those!we!refer!to!the!LD!versions!produced!in!the!SENESCHAL!project56.! o Pleiades:!a! gazetteer! for! ancient! world! studies! operated! by! the! Institute! for! the! Study! of! the! Ancient! World! (USA)57;! Pleiades! URIs! are! used! in! the! digital! classics! network! Pelagios!to! interconnect! scholarly! ancient! world! resources! through! the! places! they! refer! to;! the! Pelagios! project!provides!services!and!tools!to!allow!scholars!annotate,!aggregate,!access!and!display!the! place!references58.!! o Nomisma:!provides!as!LOD!an!ontology!for!describing!coins!and!several!numismatics!datasets!of! the!American!Numismatic!Society!and!institutions!in!Europe;!a!SPARQL!endpoint!is!available59.! o Portable!Antiquities!Scheme:!PAS!data!of!finds!in!the!UK!has!been!linked!to!LD!resources!of!the! Ordnance!Survey!(national!mapping!service),!Pleiades!(gazetteer),!British!Museum,!Nomisma!and! DBpedia60!(cf.!Pett!2014a/b).!! o LinkedARC.net61:! Frank! Lynam! (Trinity! College! Dublin),!produced! Linked! Data! of! data! of! excavations!at!Priniatikos!Pyrgos!(Crete),!modelled!primarily!using!CIDOC!CRM!and!its!type!values! link! to! terms! of! the! FISH! Archaeological! Objects! Thesaurus,! British! Museum! and! Getty! vocabularies.! The! project! is! particularly! interesting! as! it! demonstrated! the! integration! of! excavation!data!of!American!and!Irish!groups!of!archaeologists,!applying!the!Locus-Pail!method! of!excavation!and!MoLAS!single-context!method!respectively.! o MONDIS:!a!dataset!about!monument!damages!developed!in!the!Czech!research!project!MONDIS;! includes!their!diagnostic!Monument!Damage!Ontology!(Cacciotti!&!Valach!J.!2015)62.!! o MisMuseos.net:!a!“semantic!catalog”!of!museums!in!Spain!and!their!information!about!art!works! and!artists63;!the!solution! builds! on!the! GNOSS!social! and! semantic!platform! (Maturana!et! al.! 2013).!! o Musei!Italiani:!a!list!of!geo-referenced!museums!in!Italy;!that!for!museum!categories!the!dataset! links!to!DBpedia!and!for!places!to!GeoNames64.! o ReLoad!-!Repository!for!Linked!Open!Archival!Data:!a!project!of!the!Archivio!Centrale!dello!Stato,! Istituto! per! i! Beni! culturali! dell’Emilia-Romagna! and! regesta.exe!(2010-2013),! the! project! developed!ontologies!for!archival!data!sources!and!produced!a!LOD!dataset!of!several!archival! inventories;!ReLoad!provides!a!SPARQL!endpoint65.! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 55!English!Heritage!Places,!DataHub!information:!http://datahub.io/dataset/englishheritage_places!! 56!Heritage!Data:!Vocabularies,!http://www.heritagedata.org/blog/vocabularies-provided/!! 57!Pleiades,!http://pleiades.stoa.org! 58!Pelagios,!http://commons.pelagios.org!!! 59!Nomisma,!http://nomisma.org/datasets!! 60!Portable!Antiquities!Scheme,!http://finds.org.uk!! 61!Linkedarc.net,!http://linkedarc.net;!datasets,!https://datahub.io/dataset/linkedarc!! 62!MONDIS!project,!http://www.mondis.cz;!DataHub!information:!http://datahub.io/dataset?q=mondis!! 63!MisMuseos.net,!DataHub!information:!http://datahub.io/dataset/mismuseos-gnoss!! 64!Musei!Italiani,!http://www.linkedopendata.it/datasets/musei! 65!ReLoad,!http://labs.regesta.com/progettoReload/,!see!also!their!project!description!for!the!LODLAM!2013! Summit!challenge,!http://summit2013.lodlam.net/2012/12/01/challenge-entry-reload-repository-forlinked-open-archival-data/!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!41!January!2017! ! Some!of!the!datasets!listed!above!may!show!up!on!the!next!version!of!the!LOD!Cloud!diagram,!most! likely!those!which!are!maintained!and!employed!by!a!dedicated!group!of!developers!and!users!like! the!Nomisma!ontology!and!datasets!and!the!Pleiades!gazetteer,!for!instance.!! The&Art&&&Architecture&Thesaurus&(AAT)&as&a&linking&hub& Already!on!the!2014!LOD!Cloud!diagram!was!the!Art!&!Architecture!Thesaurus!(AAT)!which!the!Getty! Research! Institute! in! February! 2014! released! as! LOD.! The! multilingual! AAT! contains! over! 40,000! concepts! and! over! 350,000! terms! for! describing! objects! of! visual!art,! architecture,!other!material! heritage,!archaeology,!conservation,!archival!materials,!etc.!The! AAT!has!the!potential!to! become! one!of!the!core!linking!hubs!for!cultural!heritage!information!in!the!Linked!Open!Data!Cloud.!In!a! survey!on!Linked!Data!of!the!AthenaPlus!project!half!of!the!24!project!partners!said!they!intend!to! link!to!the!AAT!and!other!Getty!thesauri!when!they!are!available!as!LOD!(AthenaPlus!2013b:!10).! When! the! AAT! was! released! as! LOD,! among! the! initiatives! that! started! using! it! was! Europeana.! Europeana!partners!who!already!use!AAT!terms!were!invited!to!re-submit!their!metadata!so!that! their!old!AAT!term!labels!(provided!as!a!simple!text!string)!could!be!automatically!replaced!by!the! new!AAT!URIs!(Charles!&!Devarenne!2014).!This!enables!linking!to!information!of!others!on!the!web! who!use!these!URIs.!This!is!also!possible!if!data!providers!map!their!local!vocabulary!to!the!AAT.!In! ARIADNE!the!data!providers!mapped!terms!of!vocabularies!(e.g.!national!thesauri!or!own!term!lists)! which!they!use!for!their!dataset!metadata!to!appropriate!terms!of!the!AAT,!using!SKOS!mappings! (e.g.!skos:exactMatch,!skos:closeMatch!and!others).! 4.4 Brief&summary&and&recommendations& Brief&summary& The!Linked!Open!Data!Cloud!is!formed!by!datasets!that!are!openly!available!on!the!Web!in!Linked! Data!formats!and!contain!links!pointing!at!other!such!datasets.!One!task!of!the!ARIADNE!project!is!to! promote! the! emergence! of! a! web! of! interlinked! archaeological! datasets! which! comply! with! the! Linked!Open!Data!(LOD)!principles.!It!is!anticipated!that!this!web!of!archaeological!LOD!will!become! part!of!the!wider!LOD!Cloud!and!interlinked!with!related!other!data!resources.!! The!latest!LOD!Cloud!diagram!(2014)!includes!only!few!sets!of!cultural!heritage!LOD!and!they!do!not! form!a!closely!linked!web!of!Linked!Data.!None!of!the!datasets!concerns!archaeology!specifically.! Some!more!sets!of!cultural!heritage!Linked!Data!sets!exist,!also!a!few!archaeological,!but!in!2014! they! did! not! conform! to! the! criteria! for! being! included! in! the! LOD! Cloud! diagram! (e.g.! the! requirement!of!being!connected!via!RDF!links!with!at!least!one!other!compliant!dataset).!! Maybe!the!next!version!of!the!LOD!Cloud!diagram!will!contain!some!of!the!earlier!and!more!recent! sets!of!archaeological!Linked!Open!Data.!Hopefully!this!will!include!some!relevant!vocabularies!which! recently!have!been!transformed!to!Linked!Data!in!SKOS!format.!In!2014!the!only!cultural!heritage! vocabulary!on!the!diagram!was!the!Art!&!Architecture!Thesaurus!(AAT),!which!has!the!potential!to! become!one!of!the!core!linking!hubs!for!cultural!heritage!information!in!the!LOD!Cloud.! The!LOD!Cloud!is!not!a!single!entity!but!represents!datasets!of!different!providers!that!are!made! available!in!different!ways!(e.g.!LD!server,!SPARQL!endpoint,!RDF!dump)!and!the!resources!are!often! unreliable,!e.g.!many!SPARQL! endpoints!are!off-line.! There! is! no! central! management! and! quality! control!of!the!LOD!Cloud.!Webs!of!reliable!and!richly!interlinked!datasets!are!only!present!where! there!is!a!community!of!Linked!Data!producers!and!curators!(e.g.!in!the!areas!of!bio-medical!&!life! sciences!or!libraries).!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!48!January!2017! ! developers!can!build!on!the!data.!The!annotation!platform!Recogito!aids!the!process!of!identifying! places!referred!to!in!individual!digital!texts!and!maps!and!linking!them!to!a!gazetteer,!supported!by! an!automated!suggestion!system!(Simon!et!al.!2015).!Currently!in!development!is!Peripleo,!a!tool!to! explore!the!growing!pool!of!data!as!a!whole!and!to!progressively!filter!and!drill!down!to!individual! records!(Simon!et!al.!2016).! Isaksen!et!al.!(2014)!address!several!factors!which!determined!the!success!of!the!Pelagios!initiative.! Among!the!most!important!arguably!are!the!lightweight!Linked!Data!approach,!focus!on!geographical! references! as! the! most! common! feature! of! the! various! data! resources,! quick! demonstration! of! benefits!from!associating!contributors’!data,!and!the!sustained!funding!by!the!Andrew!W.!Mellon! Foundation!(since!2013,!currently!by!a!grant!until!2018100).!But!they!also!note,!“we!are!at!the!tip!of! the!iceberg!even!in!this!case!as!the!overwhelming!majority!of!classicists!and!classical!archaeologists! have!never!heard!of!Linked!Open!Data”!(Isaksen!et!al.!2014).! In!summary,!major!factors!that!contribute!to!an!advanced!position!of!the!Ancient!World!research! community!in!the!application!of!the!Linked!Data!approach!are:!a)!there!are!groups!who!develop!and! promote!description!standards!in!certain!specialities,!and!b)!there!is!a!common!platform!(Pelagios)! that! allows! linking! of! information! based! on! a! light-weight! approach.!Archaeological! projects! can! benefit!from!this!development,!for!example,!use!the!Nomisma!description!standards!for!coin!finds.! ! ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 100!Initial!funding!in!2011-2012!by!JISC!(UK)!and!grants!for!special!projects!in!2014-2015!by!AHRC!(UK)!and!Open! Knowledge!Foundation.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!49!January!2017! ! 5.4 Brief&summary&and&recommendations& Brief&summary& In!the!areas!addressed!by!this!study,!cultural!heritage!institutions!are!among!the!leading!adopters!of! the!Linked!Data!approach.!The!Ancient!World!and!Classics!research!community!is!a!front-runner!of! uptake!on! the! research! side,! while! there! have! been! only! few! projects! for! Linked! Data! of! archaeological!research!data.!! This!situation!is!due!to!considerable!differences!between!cultural!heritage!institutions!and!research! projects,! and! between! projects! in! different! domains! of! research.! For! cultural!heritage!institutions! such!as!a!libraries,!archives!and!museums!adoption!of!Linked!Data!is!in!line!with!their!mission!to! make!information!about!heritage!readily!available!and!relevant!to!different!user!groups,!including! researchers.!Adoption!has!also!been!promoted!by!initiatives!such!as!LOD-LAM,!the!International!LOD! in! Libraries,! Archives,! and! Museums! Summit! (since! 2011).! In! the! field! of! archaeological! research! there! were! no! such!initiatives! or! only! at! small!scale,!for!example!sessions! at! CAA! conferences!or! national! thematic! workshops.! But! promotional! activities,! particularly! at! the! national! level,! are! important!to!reach!archaeological!institutes!and!research!groups!and!make!them!aware!of!the!Linked! Data!approach.!! Adoption!in!the!Ancient!World!and!Classics!research!community!is!being!driven!by!specialities!such! as!numismatics!and!epigraphy,!where!there!are!initiatives!to!establish!common!description!standards! based!on!Linked!Data!principles.!The!goal!here!is!to!enable!annotation!and!interlinking!of!information! of! special! collections! or! corpora! for! research! purposes.! The! focus! on! certain! types! of! artefacts! (inscriptions,!coins,!ceramics!and!others)!provide!clear!advantages!with!regard!to!the!promotion!of! the! Linked! Data! approach! within! and! among! the! relatively! small! research! communities! of! the! specialities.!! A!good!deal!of!the!recognition!of!the!Ancient!World!and!Classics!research!community!being!a!frontrunner!in!Linked!Data!also!stems!from!the!Pelagios!initiative.!Pelagios!provides!a!common!platform! and! tools! for! annotating! and! connecting! various! scholarly! resources! based! on! place! references.! Pelagios! clearly! demonstrates! benefits!of! contributing! and! associating! data! of! the! different! contributors!based!on!a!light-weight!Linked!Data!approach.!! Archaeology!presents!a!more!difficult!situation,!in!that!the!basic!unit!of!research!is!the!site,!where! archaeologists! unearth! and! document! a! large! variety! of! built! structures,! cultural! artefacts! and! biological!material.!The!heterogeneity!of!the!archaeological!data!and!the!site!as!focus!of!analysis! present!a!situation!where!the!benefits!of!Linked!Data,!which!would!require!semantic!annotation!of! the!variety!of!different!data!with!common!vocabularies,!are!not!apparent.!Therefore!adoption!of!the! Linked!Data!approach!can!be!hardly!found!at!the!level!of!individual!archaeological!excavations!and! other!fieldwork,!but,!in!a!few!cases,!community-level!data!repositories!and!databases!of!research! institutes.!Repositories!and!databases,!not!individual!projects,!should!also!in!next!years!be!the!prime! target!when!promoting!the!Linked!Data!approach.! All!proponents!of!the!Linked!Data!approach,!including!the!ARIADNE!Linked!Data!SIG!as!well!as!the! directors!of!the!Pelagios!initiative,!agree!that!much!more!needs!to!be!done!to!raise!awareness!of!the! approach,!promote!uptake,!and!provide!practical!guidance!and!easy!to!use!tools!for!the!generation,! publication!and!interlinking!of!Linked!Data.& & & ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!50!January!2017! ! Recommendations& o More!needs!to!be!done!to!raise!awareness!and!promote!uptake!of!the!Linked!Data!approach!for! archaeological!research!data.!In!addition!to!sessions!at!international!conferences,!promote!the! approach!to!stakeholders!such!as!archaeological!institutes!at!the!national!level.! o The!prime!target!when!promoting!the!approach!should!be!community-level!data!repositories!and! databases!of!research!institutes!(not!individual!projects).! o To! drive! uptake! provision! of! practical! guidance! and! easy! to! use! tools! for! the! generation,! publication!and!interlinking!of!Linked!Data!is!necessary.!! o Promote!the!use!of!established!and!emerging!semantic!description!and!annotation!standards!for! artefacts!such!as!coins,!inscriptions,!ceramics!and!others;!for!biological!remains!of!plants,!animals! and!humans!suggest!using!available!relevant!biological!vocabularies!(e.g.!authoritative!species! taxons,!life!science!ontologies,!and!others).!! o Contribute!to!the!Pelagios!platform!(where!appropriate)!or!aim!to!establish!similar!high-visibility! data!linking!projects!for!archaeological!research!data.!! ! ! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!51!January!2017! ! 6 Requirements&for&wider&uptake&of&the&Linked&Data& approach& Linked!Open! Data! (LOD)! allow! for! semantic! interoperability!of! dispersed! and! heterogeneous! data! resources.!Despite!this!potential!LOD!is!not!produced!and!applied!yet!by!many!research!institutions! and!projects!in!the!archaeological!sector.!The!sections!of!this!chapter!address!different!requirements! and!approaches!for!fostering!a!wider!uptake!of!the!Linked!Data!approach!for!archaeological!research! data.!The! aim! is! to! present! the! current! state! with! regard! to! impediments,! potential! drivers! and! exemplary!projects,!and!for!each!area!of!identified!requirements!provide!practical!recommendations! for!Linked!Data!developers!and!other!stakeholders.! 6.1 Raise&awareness&of&Linked&Data& Linked!Data!enable!interoperability!of!dispersed!and!heterogeneous!information!resources,!allowing! the! resources! to! become!better! discoverable,! accessible! and! re-useable.!In! a! fragmented! data! landscape!as!present!in!the!sector!of!archaeology!this!is!substantial!value!proposition.!Indeed,!in!an! ARIADNE!online!survey!on!top!of!the!expectations!of!about!500!researchers,!research!directors!and! other!respondents!from!a!data!portal!were!cross-searching!of!data!archives!with!innovative,!more! powerful!search!mechanisms!(ARIADNE!2014a:!114,!about!500!respondents).!! But! such! expectations! are!not! necessarily! associated! with! capabilities! offered!by! Linked! Data.! Therefore! the!gap! between! advantages!expected! from! advanced!data! services! and! “buy! in”! and! support!of!the!research!community!for!Linked!Data!must!be!closed!by!targeted!actions.!This!section! addresses! the! situation! of! a! highly! fragmented! landscape! of! archaeological! data,! presents! some! available! results! on! the! awareness! of! Linked! Data! by! cultural! heritage! organisations! and! archaeologists,!and!suggests!whom!to!consider!as!priority!target!groups!for!Linked!Data!initiatives.! 6.1.1 Fragmentation&of&archaeological&data& The!ARIADNE!“First!Report!on!Users’!Needs”!(ARIADNE!2014a)!identified!major!general!factors!that! impede!the!uptake!of!the!Linked!Data!approach!in!the!domain!of!archaeological!research.!The!results! of!the!literature!review,!pilot!interviews!and!online!survey!made!clear!that!the!archaeological!data! landscape!is!characterized!by!high!fragmentation!due!to!several!factors.!These!factors!include,!but! are!not!limited!to!!! - diverse! organisational! settings! (research! institutes,! heritage! management! agencies,! museums! and!others)!in!which!data!are!collected!and!managed,!! - data!management!practices!that!are!predominantly!focused!on!individual!projects,!rather!than! an!institutional!or!domain!oriented!perspective!(e.g.!“project!archives”,!one!per!excavation!site,! stored!on!a!file!servers,!etc.),!! - a!low!level!of!open!sharing!of!research!data,!due!to!lack!of!recognition!and!rewards!for!making! the!data!available,!the!additional!work!effort!for!documenting!data!sets!for!proper!archiving,!and! lack!of!community!archives!in!many!countries.!! The!situation!does!not!present!favourable!conditions!for!the!integration!and!linking!of!archaeological! data!sets!through!data!e-infrastructures!such!as!ARIADNE.!Therefore!ARIADNE!encourages!initiatives! to!establish!state-of-the-art!community-level!data!archives!in!countries!where!they!are!missing!at! present.!This!suggestion!is!in!line!with!the!development!that!research!funders!increasingly!demand! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!52!January!2017! ! data! management! &! access! plans! with! the! goal! to! make! the! generated! research! data! openly! accessible!through!digital!archives!(open!data!mandates).!! Research! projects! will! have! to! think! about! data! management! from! the! start,! including! where! to! deposit!their!data,!required!metadata,!and!licensing!agreements.!Also!some!scientific!journals!now! require! a! data! availability! statement,! i.e.! that! the! data! which! underpins! published! research! is! available!in!an!accessible!archive.!However!with!regard!to!promoting!archaeological!Linked!Data!the! primary!focus!must!not!necessarily!be!individual!researchers,!research!groups!and!projects.!Because! data!produced! by!projects!will!increasingly!be!deposited!in!accessible!data! archives,!according! to! sector!standards!with!regard!to!metadata!and!vocabularies.!! 6.1.2 Current&awareness&of&Linked&Data&& Results&for&cultural&heritage&organisations& It! is! worthwhile! having! an! indication! of! the! current! state! of! awareness! and! knowledge! of!Linked! Open! Data! (LOD)! at! cultural! heritage! organisations,! some! of! which! may! curate!archaeological! artefacts!among!other!objects!and! content.! The!AthenaPlus! project101!conducted! a! survey! among! partners!and!other!organisations!about!their!awareness!of!LOD!and!existing!initiatives,!how!they!get! information! about! LOD,! and!if! they! already! use! LOD! (AthenaPlus! 2013b).! 28! questionnaires! were! returned!by!respondents!of!organisations!located! in! 16!EU! countries.!The! respondents! worked!at! museums,! libraries,! archives,! data! aggregators! and! other! organisations,! including! ministries,! governmental!agencies,!university!research!centres!and!IT!service!organisations.!Thus!a!rather!small! number!of!responses!from!diverse!organisations!were!received.!The!survey!results!were!as!follows:! Questions& Yes& No& Are!you!or!your!organisation!familiar!with!the!concept!of!Linked!Open!Data!(LOD)?! 25! 3! Do!you!or!your!organisation!know!of!any!LOD!projects!or!initiatives!in!your!country!in! the!field!of!cultural!heritage?! 19! 9! Have!you!or!your!organisation!had!experience!of!using!LOD!in!connection!with!your! collections?! 6! 22! Have!you!or!your!organisation!had!experience!of!publishing!LOD!in!connection!with! your!collections?! 4! 24! Does!your!organisation!plan!to!publish!LOD!in!the!near!future?! 21! 7! Does!your!organisation!plan!to!connect!with!new!LOD!sources!in!the!near!future?!(1! did!not!answer!this!question)! 14! 13! In!summary,!most!respondents!to!the!AthenaPlus!survey!said!that!they!(or!their!organisation)!are! familiar!with!Linked!Open!Data!and!knew!of!related!projects!and!initiatives!in!their!country.!But!only! few! had! first-hand!experience! with! LOD.! At! the! same! time,! most! had! plans! to! publish! and/or! consume!LOD!in!the!near!future.! Sixteen!respondents!answered!an!open!question!on!their!expectations!from!connecting!own!data! with! LOD!resources.! According! to! the! survey! authors! the! most! common! expectations! related! to! “enlarging!accessibility!of!data!in!a!broader!context,!increasing!the!visibility!of!collections,!extend!the! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 101!AthenaPlus!(EU,!CIP!Best!Practice!Network,!3/2013-8/2015),!http://www.athenaplus.eu!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!53!January!2017! ! semantic! relations! between! various! collections,! development! of! cross-domain! interdisciplinary! networks! of! knowledge,! possibility! of! re-contextualizing! the! resources! for! improved! research! infrastructure.!Recognized!as!an!added!value!for!the!own!collections!was!the!possibility!to!enrich!own! data!via! (inter)national!connections.! One!reply!mentioned!the!prospect!of!easy!access!to! valuable! information!for!scientific!research!and!the!purpose!to!create!educational!apps.”! Some!respondents!also!considered!possible!disadvantages,!which!included!loss!of!control!over!own! published!data,!a!decrease!in!data!quality!due!to!links!to!non-qualified!sources,!or!an!overload!of! links!which!might!cause!a!loss!of!visibility!and/or!accessibility.! ARIADNE&results&for&archaeology& One!observer!of!the!Semantic!Web!community!notes:!“In!contrast!to!the!cultural!heritage!sector!aka! museums,! the! Semantic! Web! has! seen! less! uptake! in! archaeology.! This! could! be! because! archaeologists! tend! to! focus! on! analysis! and! recording! of! the! data! rather! than! dissemination.! Experiences! are! mostly! limited! to! spreadsheets,! relational! databases! and/or! spatial! data! management.!Many!academic!archaeologists!remain!protective!of!their!data!especially!when!it!has! not! been! published! in! traditional! media.! The! complexity! of! combining! siloed! resources! may! be! overwhelming”!(Solanki!2009).! However,!researchers!are!not!necessarily!the!primary!target!group!of!Linked!Data!awareness!raising! actions.!The!online!survey!reported!in!ARIADNE’s!“First!Report!on!Users’!Needs”!(ARIADNE!2014a! [April!2014])!had!one!question!about!how!helpful!researchers!and!data!managers!perceive!different! services! ARIADNE! might! provide.! Among! nine! options! there! was! “Improvements! in! linked! data”,! defined! as! “interlinking! of! information! based! on! Linked! Data! methods! (i.e.! methods! of! publishing! structured!data!so!that!it!can!be!interlinked)”.!! Not!surprisingly,!this!option!was!at!the!bottom!of!the!researchers’!list!of!perceived!helpfulness,!only! the! service! option! “Content! recommendations! based! on! collaborative! filtering,! rating! and! similar! mechanisms”!fared! worse.!But!of!the! over!470! researchers!who!answered!the!question! still! 37%! thought!“Improvements!in!linked!data”!could!be!“very!helpful”!and!43%!“rather!helpful”!(ARIADNE! 2014a:!114).!The!good!results!for!“Improvements!in!linked!data”!indicate!that!interlinking!of!research! results!is!generally!relevant!to!researchers!and,!arguably,!that!quite!some!researchers!had!already! heard!about!Linked!Data!as!a!novel!way!of!interlinking!information.! An!additional!survey! addressed!repository!managers!that! are! a! considerably! smaller! target! group! than!researchers.!The!survey!received!52!sufficiently!filled!questionnaires,!hence!a!good!response! but! certainly! not! representative.! The! managers! were! asked! if! their! repository! and! clients! could! benefit! from! services! ARIDANE! might! provide,! presenting! the! same! list! of! service! options! as! the! survey! of! researchers.! Among! the! managers! who! answered! the! question! (32),! the! option! “Improvements!in!linked!data”!fared!better:!it!came!in!on!position!five!of!the!nine!options!with!39%! “very!helpful”!and!39%!“rather!helpful”.!The!favourite!was!“Services!for!Geo-integrated!data”,!52%! “very!helpful”,!32%!“rather!helpful”!(ARIADNE!2014a:!141).!! The!repository! managers! in!general!were! more! sceptical!about! potential!improvements,!but! they! appreciated!“Improvements!in!linked!data”!considerably!more!than!the!researchers.!As!noted,!the! results!for!the!data!managers!are!far!from!representative.!But!we!think!that!they!are!indicative!and! add!to!our!view!that!data!managers!are!a!more!relevant!target!group!for!the!Linked!Data!approach! than! researchers.! Data! managers! are!active! in! different! contexts,! digital! archives! of! the! research! community,! repositories!of! individual! institutions! (e.g.! university,! research! center),! and! large! archaeological! projects! in! need! of! systematic! and! long-term! data! management.!Within! ARIADNE,! consultancy!and! training!for!Linked!Data!has! been!mainly!given!to!managers!of!institutional!data! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!54!January!2017! ! resources!with!regard!to!vocabularies!that!are!being!used!for!the!metadata!of!the!resources,!e.g.! related!to!the!mapping!of!the!vocabularies!to!the!Art!&!Architecture!Thesaurus.! In!the!ARIADNE!portals!survey!for!the!“Second!Report!on!Users’!Needs”!(ARIADNE!2015a)!23!experts! of! project! partners! (18! of! which! archaeologists)! studied! existing! information! portals,! defined! as! websites! that! provide! access! to! content! of! more! than! one! institution! or! project.! The! aim! was! to! identify!good!practices!and!give!further!ideas!for!the!development!of!the!ARIADNE!data!portal.!Some! participants! considered! Linked! Data! for! integrating! information! within! the! portal! and! linking! to! external!resources.!The!statements!addressed!the!potential!of!the!Linked!Data!approach!as!well!as! the!current!lack!of!awareness!of!the!benefits!of!such!data;!also!the!need!of!high-quality!Linked!Data! was!mentioned!(ARIADNE!2015a:!103-104).!! The! suggestions! of! the!survey! participants! concerning! Linked! Data! were!summarised! in! three! recommendations!for!the!ARIADNE!data!portal!and!evaluated!by!project!partners!(28!experts)!with! regard!to!their!relevance!and!time-horizon!(ARIADNE!2015e:!282-287).!Among!the!top-ranked!of!all! 34! recommendations! of! the! portals! survey! was! “Deploy! Linked! Open! Data! (LOD)! to! integrate! information!within!the!portal!and!to!link!to!external!resources!which!follow!LOD!principles!(e.g.!HTTP! URIs!and!RDF)”.!79%!of!the!evaluators!considered!this!as!relevant!and!86%!thought!that!it!might!be! achieved!within!the! formal!duration!of! the!project!(until!January!2017).!The! evaluators!were! less! confident! with! regard! to! encouraging! a! wider! uptake! of! LOD! principles! among! archaeological! institutions!and!projects,!but!about!60%!expected!that!the!project!will!promote!this.! 6.1.3 Brief&summary&and&recommendations& Brief&summary& Linked!Data!enable!interoperability!of!dispersed!and!heterogeneous!information!resources,!allowing! the! resources! to! become! better! discoverable,! accessible! and! re-useable.! In! the!fragmented! data! landscape!of!archaeology!this!is!substantial!value!proposition.!In!the!ARIADNE!online!survey!on!top! of! the! expectations! of! the! archaeological! research! community! from! a! data! portal! were! crosssearching!of!data!archives!with!innovative,!more!powerful!search!mechanisms.!But!such!expectations! are!not!necessarily!associated!with!capabilities!offered!by!Linked!Data.!Therefore!the!gap!between! advantages!expected!from!advanced!services!and!“buy!in”!and!support!of!the!research!community! for!Linked!Data!must!be!closed!by!targeted!actions.!! A!small!survey!of!the!AthenaPlus!project! (2013)! indicated! that!cultural! heritage! organisations!are! already! aware! of! Linked! Data,! but! few! had! first-hand! experience! with! such! data.! Among! the! expectations!from!connecting!own!and!external!Linked!Data!resources!were!increasing!the!visibility! of! collections! and! creating! relations! with! various! other!information! resources.! Some! respondents! also! considered! possible! disadvantages,! e.g.! loss! of! control! over! own! data! or! a! decrease! in! data! quality!due!to!links!to!non-qualified!sources.! In!the!ARIADNE!online!survey!(2013)!“Improvements!in!linked!data”,!i.e.!interlinking!of!information! based!on!Linked!Data!methods!to!enable!better!information!services,!was!considered!more!helpful! by!repository!managers!than!researchers.!Researchers!of!course!perceive!interlinking!of!information! as! important,! but! may! not! see! this! as! an! area! for! own! activity.! Indeed,! we! think! individual! researchers!and!research!groups!should!not!be!a!primary!focus!of!Linked!Data!initiatives.!Managers! of!digital!archives!of!the!research!community!and!institutional!repositories!are!much!more!relevant! target!groups.!Furthermore!data!managers!of!large!and!long-term!archaeological!projects!should!be! addressed!as!they!will!also!consider!required!standards!for!data!management!and!interlinking!more! thoroughly.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!55!January!2017! ! Recommendations& o Address!the!highly!fragmented!landscape!of!archaeological!data!and!highlight!that!Linked!Data! can!allow!dispersed!and!heterogeneous!data!resources!become!better!integrated!and!accessible.! o Consider! as! primary! target! group! of! Linked! Data! initiatives! not! individual! researchers! but! managers!of!digital!archives!and!institutional!repositories.! o Include!also!data!managers!and!IT!staff!of!large!and!long-term!archaeological!projects!as!they! will!also!consider!required!standards!for!data!management!and!interlinking!more!thoroughly.! 6.2 Clarify&the&benefits&and&costs&of&Linked&Data& One!targeted!action!to!help!close!the!current!Linked!Data!adoption!gap!in!the!archaeological!sector! could!be!removing!the!widespread!notion!of!an!unfavourable!ratio!of!costs!compared!to!benefits!of! employing! Semantic! Web! /! Linked! Data! standards!for! information! management,! publication! and! integration.!While!the!standards!have!matured!and!become!much!better!applicable!this!notion!is!still! prevalent!and!a!barrier!to!wider!adoption!of!the!Linked!Data!approach.!! 6.2.1 The¬ion&of&an&unfavourable&cost/benefit&ratio& In!a!paper!titled!“Is!Participation!in!the!Semantic!Web!Too!Difficult?”,!published!in!2002,!the!authors! emphasised! the! need! of! lowering! the! entry! barrier! for! cultural! heritage! organisations,! especially! small! ones,! by! offering! significant! added! value! and! advantages! over! established! ways! of! content! management! and! publication! (Haustein!&! Pleumann! 2002).! The! authors! note! that! initial! steps! towards!the!Semantic!Web!will!require!some!extra!effort!and,!therefore,!“the!system!needs!to!ensure! that!this!cost!is!outweighed!by!the!gain!for!the!content!provider.!This!gain!should!not!count!too!much! on!the!network!effect!of!the!Semantic!Web,!because!this!effect!might!take!some!time!to!really!pay! off.!Instead,!the!gain!has!to!be!immediately!visible!to!the!content!provider.”!! In!the!DigiCULT!Forum!thematic!issue!“Towards!a!Semantic!Web!for!Heritage!Resources”!(2003)!the! position! paper! stressed! that! it! is! difficult! to! legitimate! investment! of! institutions! in! the! Semantic! Web,!because!over!the!next!five!years!it!would!bring!little!benefit!(Ross!2003).!A!DigiCULT!Forum! assessment!in!2004!of!the!readiness!of!heritage!institutions!for!several!e-culture!technologies!argued! that!Semantic!Web!technologies!would!be!adopted!primarily!by!large!institutions!in!a!longer-term! perspective!of!6!or!more!years!(Geser!2004).!! With!regard!to!an!archaeological!semantic!Web!Julian!Richards!in!2006!noted!an!increase!in!online! available!documents!and!archives!so!that!“there!should!be!no!shortage!of!content!with!which!to!build! such!a!web”;! however!“archaeology!could!get! left!behind!if!the! rewards!for!creating!the! mark-up! necessary!to!make!the!Semantic!Web!a!reality!are!only!evident!in!the!commercial!sector.!The!sector!is! currently!more!likely!to!participate!in!Berners-Lee’s!vision!through!the!creation!of!semantic!mark-up! for!information!about!monument!access!arrangements,!opening!hours!and!facilities!for!the!tourism! industry!than!for!academic!research”!(Richards!2006:!977).!! Reasons!for!the!doubts!of!a!quick!adoption!of!Semantic!Web!standards!and!technologies!included! still!on-going!standardization!work,!need!for!specialist!knowledge,!little!experience!of!implementation! under! real! world! conditions! and,! in! particular,! expected! high! costs! of! conversion! of! legacy! metadata!and!knowledge!organization!systems!such!as!thesauri!to!Semantic!Web!standards.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!56!January!2017! ! 6.2.2 Lack&of&cost/benefit&evaluation& Unfortunately,!little!effort!has!been!invested!so!far!to!make!clear!cost!/!benefit!ratios!of!different! levels!and!ways!in!which!Linked!Data!can!be!produced!and!employed.!Among!the!exceptions!is!a! model!that!considers!“pay-off!points”!of!five!escalating!levels!at!which!information!can!be!formalized! (Isaksen!et!al.!2010a/b).!The!purpose!of!the!model!is!to!encourage!a!step-wise!adoption!of!Linked! Data! principles,! including! for! small-scale! data! sources! (i.e.! “small! tail”! data! sets).! The! authors! consider!that!“(at!least)!five!escalating!levels!of!semantic!formalization!can!be!identified,!each!with! differing!requirements!and! benefits!for!the!implementer:!i.!Literal!Standardization,!ii.!Instance!URI! generation,! iii.! Canonical! URI! mapping,! iv.! RDF! generation,! and! iv.! Database-schema-to-Ontology! mapping”!(Isaksen!et!al.!2010a).!! In!this!scheme!(i)!means!the!creation!and!use!of!a!locally!defined!restricted!vocabulary!(e.g.!list!of! terms! or! thesaurus),!(ii)! the! creation! of! web-accessible! unique! identifiers! for!the! proprietary! vocabulary!terms,!and!(iii)!mapping!of!the!terms!to!established!concepts/terms!of!an!acknowledged! authority.!The!suggested!approach!seems!at!odds!with!the!Linked!Data!principle!that!projects!should! wherever! possible! re-use! established! vocabulary,! however! “normalization”! of! terms! will! often! be! necessary!when!attempting!to!integrate!different!legacy!datasets.!This!was!the!case!in!the!Roman! Ports!in!the!Western!Mediterranean!Project!(Isaksen!et!al.!2009)!to!which!the!authors!refer!in!the! discussion!of!the!suggested!scheme!of!semantic!formalization.!! The!authors!emphasise!“that! Linked! Data! –! hitherto! seen! as! the! simplest! semantic! approach! –! is! relatively!advanced!in!this!scheme.!We!argue!that!data!providers!should!be!encouraged!to!migrate! towards!full!semantic!formalization!only!as!their!requirements!dictate,!rather!than!all!at!once.!Such! an! approach! acts! as! both! a! short! and! long-term! investment! in! semantic! approaches,! in! turn! encouraging! increased! community! engagement.! We! also! propose! that! for! such! processes! to! be! accessible!to!data-curators!with!low!technical!literacy,!assistive!software!must!be!created!to!facilitate! these!steps”!(Isaksen!et!al.!2010a).!! The! authors! also! address! benefits! and! costs! (or,! rather,! requirements)! of! the! different! levels! of! semantic!formalization,!although!only!generically.!For!example,!that!RDF!generation!allows!machines! to!exploit!the!URI!linkage!for!data!aggregation!and!discovery,!but!requires!a!basic!grasp!of!ontological! modelling,!selection!and/or!creation!of!predicate!URIs,!tools!or!scripting!for!the!RDF!generation,!and! maybe!new/unfamiliar!RDF!data!storage!mechanisms.!! The!suggested!approach!of!a!stepwise!migration!towards!Linked!Data!seems!reasonable.!But!without! a!method!for!evaluating!the!“pay-offs”!in!terms!of!the!cost/benefit!ratio,!and!a!number!of!reference! examples,! it! will! remain! theoretical!and! of! little! help! in! driving! “buy! in”! of! potential! Linked! Data! providers.!! The!key!point!of!the!approach!is!to!look!for!different!levels!at!which!Linked!Data!can!be!employed.!In! this! regard! Eric! Kansa! of! the! archaeological! data! publication! platform! Open! Context! provides! a! helpful!discussion!of!what!can!be!considered!as!medium!and!high-level!routes!to!Linked!Data!(above! the!low-level!semantic!formalizations!mentioned!by!Isaksen!et!al.).! Kansa!(2014a)!sees!the!medium-level!route!in!annotation!and!cross-referencing!of!data!using!shared! controlled!vocabularies,!while!the!high-level!is!represented!by!employing!the!CIDOC!CRM!to!align! datasets!based!on!shared!conceptual!modelling!(level!iv.!“Database-schema-to-Ontology!mapping”!in! the!model!suggested!by!Isaksen!et!al.!2010a).!Referring!to!experiences!from!Open!Context!projects! Kansa!is!convinced!“that!vocabulary!alignment!can!help!researchers!more,!at!least!in!the!near-term,! than!aligning!datasets!to!elaborate!semantic!models!(via!CIDOC-CRM)”.!At!least!it!allows!reaching! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!57!January!2017! ! “some! lower-hanging,! easier! to! reach! fruit! in! our!efforts! to! make! distributed! data! work! better! together”!and!“meet!more!immediate!research!needs”.! One! example! of!such! a! project! employed! annotations! to! common! vocabularies! to! enable! the! integration! and! comparison! of! zooarchaeological! datasets!from! 17! sites!(in! total! over! 294,000! records!of!bone!specimens).!Each!dataset!had!its!own!organization!(schema)!and!used!somewhat! different! proprietary! vocabulary/terminology.!The! project! annotated!dataset-specific! taxonomic! categories! with! Web! URIs! for! animal! taxa! curated! by! the! Encyclopedia! of! Life102,! annotated! classifications! of! bone! elements! with! concepts! of! the! Uber! Anatomy! Ontology!(UBERON)103,! and! employed!a! vocabulary! developed! by! Open! Context! for! bone! fusion,! sex! determinations! and! standard! measurements.! The! vocabulary! alignments! provided! the! basis! for! data! integration! and! comparison!across!the!different!datasets!(Arbuckle!et!al.!2014;!Kansa!et!al.!2014;!Whitcher-Kansa! 2015).!! Concerning!the!CIDOC!CRM,!the!high-level! route!of!aligning!datasets! based!on! shared! conceptual! modelling,! despite! its! increasing! adoption!little! is! known! about! the! cost! /! benefit! ratio.!While! considerable!benefits!have!been!reported!in!some!cases,!the!cost!side!is!usually!not!addressed.! For!example,!Jordal!et!al.!(2012)!report!benefits!and!new!opportunities!opened!up!by!the!CRM-based! integration!of!ethnographic!collections!held!by!the!Museum!of!Cultural!History!in!Oslo.!Connecting! the!collections!via!a!CRM-based!model!allows!the!curators!integrated!access!to!the!legacy!catalogues! and! databases,! and! the! model! also! guides! the! registration! of! new! items.! The! integration! of! the! collections!also!“gives!a!better!basis!for!telling!a!story!for!each!artefact”,!and!“provides!a!possibility! to!do!research!on!the!objects!with!as!complete,!accurate!and!rich!data!as!possible”.!! Other! institutions! have! achieved! a! lot! by!applying! the! CIDOC! CRM!to! integrate! large! and! heterogeneous! datasets,! enable!advanced! search! on! their! website,! and! participate! in! cultural! heritage!web!portals.!One!outstanding!example!in!this!regard!is!Arachne,!the!central!object!database! of!the!German! Archaeological! Institute!(DAI)! and!the!Archaeological!Institute! of! the! University! of! Cologne104.!The!CIDOC!CRM!based!internal!integration!of!data!allows!advanced!exploration!of!a!mass! of!heterogeneous!information!resources.!Arachne!also!participates!in!CLAROS!-!Classical!Art!Research! Online!Services!(launched!in!May!2011)105!which!provides!a!portal!for!searching!several!sources!for! Classical!studies!based!on!the!Linked!Data!approach!and!CIDOC!CRM.!! Oldman!&!Rahtz!(2014)!highlight!that!the!CLAROS!project!“established!the!credentials!of!the!CIDOC! CRM!standard!as!a!semantic!framework!that!can!harmonise!data!from!many!different!institutions! while!providing!a!richer!environment!(when!compared!to!its!digital!sources)!in!which!to!explore!and! research! cultural! heritage! data”.! But! the! CLAROS! Linked! Data! based! search! environment! offers! rather!limited!research!functionality.!The!ResearchSpace!project106,!in!which!Dominic!Oldman!serves! as!principal!investigator,!aims!to!enable!advanced!exploration!and!research!of!CIDOC!CRM!mediated! cultural!heritage!data.! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 102!Encyclopedia!of!Life,!http://eol.org!! 103!UBERON!-!Uber!Anatomy!Ontology,!http://uberon.org!! 104!Arachne,!http://arachne.uni-koeln.de!! 105!CLAROS,!http://www.clarosnet.org;!http://data.clarosnet.org!! 106!ResearchSpace,!http://www.researchspace.org!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!64!January!2017! ! The!LOD!Around!the!Clock!(LATC)!project!warns!that!a!lot!of!open!source!Linked!Data!software!tools! are!not!completed,!well-tested!and!stable.!The!developers!often!lose!interest!in!a!project!“leaving! users!stranded!without!improvements!or!support”!(LATC!2012:!10-11,!includes!a!list!of!questions!to! consider!in!the!evaluation!of!relevant!tools).!LATC,!LOD2119!and!other!projects!present!selected!tools! for!different!phases!of!the!Linked!Data!life!cycle,!but!the!selection!is!often!informed!by!what!project! participants!have!on!stock.!Moreover!tools!suggested!by!projects!completed!two!or!three!years!ago! may!already!be!superceded!by!new!ones!with!features!that!are!improved!in!some!respects.!! In!short,!new!entries!in!the!realm!of!Linked!Data!should!look!which!tools!are!being!used!by!similar! other!projects!and!consult!with!experts!in!the!field!which!ones!will!fit!best!for!their!data!and!goals.!! 6.3.2 Need&of&expert&support& Arguably!all!Linked!Data!showcases!in!the!field!of!cultural!heritage!so!far!depended!heavily!on!the! support!of!experts!who!are!familiar!with!the!required! methods! and!tools,!often!their!own.!Many! projects! have! been! by!experts! together! with! museums,! starting! with! the! path-breaking! Finnish! Museums! on! the! Semantic! Web!project!(Hyvönen! et! al.! 2002)! up! to! more! recent! projects!at! the! Amsterdam!Museum!(de!Boer!et!al.!2012!and!2013),!Gothenburg!City!Museum!(Damova!&!Dannells! 2011),!Peter!the!Great!Museum!of!Anthropology!and!Ethnography!in!St!Petersburg!(Ivanov!2011),! Russian! Museum! in! St.! Petersburg! (Mouromtsev!et! al.! 2015),! Smithsonian! American! Art! Museum! (Szekely!et!al.!2013),!natural!history!museums!in!the!Natural!Europe!project!(Skevakis!et!al.!2013),! and! others.120!One! reason! for! the! strong! presence! of! museums! is! that! they! wish! to! make! their! collections! more! accessible! to! the! public,! and! may! more! easily! do! this! by! drawing! on! popular! resources!such!as!Wikipedia!via!DBpedia!Linked!Data.! A!much!wider!generation!and!use!of!cultural!heritage!and!archaeology!Linked!Data,!especially!also! for!research!purposes,!!requires!appraochs!that!allow!non-experts!to!do!the!work!with!easy!to!use! tools! and! little! training! effort.! But! this! may! remain! an! illusory! goal.! As! Eric! Morgan,! the! lead! researcher!of!the!Linked!Archival!Metadata!(LiAM)!notes:!"Linked!data!might!be!a!'good!thing',!but! people!are!going!to!need!to!learn!how!to!work!more!directly!with!it"!(Morgan!2014).!He!suggests! practical!tutorials,!hands-on!training!on!how!Linked!Data!can!be!put!into!practice,!and!hackathons! involving!practitioners!and!Linked!Data!specialists.!! In!short,!turning!substantial!legacy!collections!or!research!datasets!into!Linked!Data!resources!will! hardly! be! possible! without! support! of! specialists,! at! least! for! some! steps! in! the! process.! As! a! summary!of!a!discussion!on!skills!required!for!Linked!Data!puts!it,!“Realistically,!for!many!people,! expertise!needs!to!be!brought!in.!Most!organisations!do!not!have!resources!to!call!upon.!Often!this!is! going!to!be!cheaper!than!up-skilling!–!a!steep!learning!curve!can!take!weeks!or!months!to!negotiate! whereas!someone!expert!in!this!domain!could!do!the!work!in!just!a!few!days”!(Stevenson!2011).! 6.3.3 The&case&of&CIDOC&CRM:&from&difficult&to&doable& A!special!case!of!a!difficult!adoption!process!is!the!CIDOC!Conceptual!Reference!Model,!which!is!a! core! for! cultural! heritage! information! exchange! and! integration.! The! CIDOC! CRM!is! an! ontology! represented!in!RDF!Schema!(RDFS)!and!considered!as!a!key!integrator!of!heterogeneous!datasets!in! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 119!LOD2!-!Creating!Knowledge!out!of!Interlinked!Data!(EU,!FP7-ICT,!2010-2014),!http://lod2.eu!! 120!Some!other!examples!are!listed!on!the!Museums!and!the!Machine-processable!Web!wiki,!e.g.!Auckland! Museum!(New!Zealand);!British!Museum!(UK),!Harvard!Art!Museums!(USA);!National!Maritime!Museum! (UK)!and!others,!http://museum-api.pbworks.com/w/page/21933420/Museum%C2%A0APIs!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!65!January!2017! ! the!emerging!web!of!cultural!heritage!Linked!Data.!The!ontology!became!an!official!ISO!standard!in! 2006! (ISO! 21127:2006,! updated! in! 2014),! which! is! but! one! factor! that! contributed! to! its! wider! adoption!in!the!cultural!heritage!sector,!including!archaeology.! The!increasing!use!of!the!CIDOC!CRM!in!recent!cultural!heritage!Linked!Data!projects!is!noteworthy.! In!its!early!days!the!CIDOC!CRM!was!perceived!as!difficult!to!apply!by!researchers!and!practitioners! who!were!not!involved!in!its!development!and!related!demonstration!projects.!For!example,!in!the! SCULPTEUR! project! (2002-2005)! museum! databases! were! mapped! to! the! CRM! to! implement! concepts-based! cross-collections! search! &! retrieval.! The!implementers! reported! that! “mapping! is! complex! and! time! consuming.! The! CRM! has! a! steep! learning! curve,! and! performing! the! mapping! requires!a!good!understanding!of!both!ontological!modelling!as!well!as!the!source!metadata!system.! Eventually! the! assistance! of! a! CRM! expert! was! required! to! complete! and! validate! the! mappings”! (Sinclair!et!al.!2005).!! Indeed,!the!CIDOC!CRM!is!a!complex!ontology!that!requires!a!good!understanding!of!its!event-centric! modelling!approach!as!well!as!how!to!apply,!extend!or!specialise!the!ontology!for!a!particular!use! case,!if!required.!Researchers!of!the!BRICKS!project!(2004-2007)!noted!the!abstractness!of!the!CRM! concepts! and! lack! of! technical! specification! as! factors! that! could! impede! the! goal! of! enabling! interoperability! across! heterogeneous! databases! (Nußbaumer! &! Haslhofer! 2007;! see! also! Nußbaumer!et!al.!2010).!! Similar!statements!can!be!found!elsewhere,!for!example,!one!respondent!to!Leif!Isaksen’s!survey!on! cultural! heritage! and! archaeology! Semantic! Web! projects! wrote:! “CIDOC! CRM! is! bloody! hard! to! understand!and!use!with!zero!tool!support!available!at!the!time.!Museum!bods!are!understandably! not! knowledge! engineers,! so! require! lots! of! support”!(in! Isaksen! 2011:!203).! On! the! other! hand,! Dominic!Oldman!(2012)!notes!that!some!of!the!issues!pertain!to!“a!lack!of!domain!knowledge!by! those!creating!cultural!heritage!web!applications.!The!CRM!exposes!a!real!issue!in!the!production!and! publication!of!cultural!heritage!information!about!the!extent!to!which!domain!experts!are!involved!in! digital! publication! and,! as! a! result,! its! quality!(…)! The! CRM! requires! real! cross! disciplinary! collaboration!to!implement!properly!–!and!this!type!of!collaboration!is!difficult.”!! Meanwhile!a!number!of!exemplary!CIDOC!CRM!use!cases,!available!documentation!and!sharing!of! know-how!among!practitioners!have!enabled!more!projects!large!and!small!applying!the!ontology.! However!newcomers!will!still!often!need!expert!guidance,!as!has!been!given!to!ARIADNE!partners!by! FORTH-ICS’!Centre!for!Cultural!Informatics!on!modeling!scientific!archaeological!data121.! 6.3.4 Progress&through&data&mapping&tools&and&templates& Projects!on!databases!of!heritage!collections!reported!considerable!difficulties!in!getting!to!Linked! Data!and!archaeological!research!datasets!arguably!pose!even!greater!challenges.!For!example,!the! datasets!that!were!mapped!in!the!Roman!Ports!in!the!Western!Mediterranean!Project!are!described! as! follows:! “While! the! datasets! all! pertain! to! the! same! domain,! they! frequently! employ! mixed! taxonomies! and! are! heterogeneously!structured.! Normalization! is! rare,! uncertainty! frequent! and! variant! spellings! common.! Different! recording! methodologies! have! also! given! rise! to! alternative! quantification!and!dating!strategies.!In!other!words,!it!is!a!typical!real-world!mixed-context!situation”! (Isaksen!et!al.!2009).! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 121!Cf.!ARIADNE!(2014b),!website:!Modeling!scientific!data:!workshop!report,!12!September!2014,! http://www.ariadne-infrastructure.eu/News/Modeling-scientific-data!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!66!January!2017! ! But!a!number!of!projects!have!reported!advances! toward! the! goal! of!enabling!non-experts!apply! semantic!standards!and!tools.!The!data!mapping!tools!that!were!developed!and!employed!in! the! Roman!Ports!project!“have!proven!remarkably!successful!against!a!broad!range!of!sample!datasets! from!four!different!countries!(UK,!Spain,!France,!Italy).!The!most!important!achievement!has!been!to! enable! domain! experts! to! provide! data! derived! in! different! contexts! as! ontology-compliant! Linked! Data! extremely! quickly! and! sustainably.! Previous! attempts! to! produce! homogeneous! RDF! have! generally!required!a!lengthy!and!expensive!mapping!process!against!one!or!two!large!resources.!We! feel!that!making!it!possible!for!‘the!long!tail’!of!archaeological!data!is!a!vital!task!in!the!Linked!Data! revolution”!(Isaksen!et!al.!2009).! Similarly,! the!Linked!Data!toolkit!developed!in!the! STELLAR122!project!has! been!reported!to!allow! non-expert!users!mapping!and!extracting!archaeological!datasets!to!XML/RDF!conforming!to!CIDOC! CRM,! CRM-EH!(English! Heritage)!or! CLAROS! CRM! Objects!concepts! and! relations.! The! toolkit! comprises!of!an!open!source!software!tool!(Stellar!Console)!and!a!set!of!customizable!templates.!The! approach!taken!was!to!identify!a!set!of!commonly!occurring!patterns!in!domain!datasets!and!the! CIDOC!CRM,!and!express!them!in!a!set!of!mapping!templates.!! Tudhope!et!al.!(2013)!note!that!with!the!CIDOC!CRM!the!same!semantics!underlying!cultural!heritage! datasets! can! be! mapped! in! different! ways,! which!raises!barriers! for! semantic! interoperability! the! CRM!aims!to!enable.!CRM!adopters!needed!mapping!guidelines!and!templates!for!general!use!cases! in!their!domain!(e.g.!archaeology).!Therefore!the!STELLAR!project!made!available!a!facility!for!userdefined!templates!as!well!as!helpful!tutorials!with!worked!examples123!(Binding!et!al.!2015!present!in! detail!the!template!use!for!archaeological!datasets!and!a!case!study!with!non!expert!users).!! The!STELLAR!templates!have!been!adapted!and!used!by!other!projects.!For!example,!the!ArcheoInf! project124!aimed!to!develop!a!database!that!combines!and!integrates,!through!mappings!to!CIDOC! CRM,!data!of!archaeological!surveys!and!excavations!conducted!by!German!university!institutes!of! classical! archaeology.! Adapted! STELLAR! templates! allowed!exporting!datasets!tagged! with! CIDOC! CRM!mappings!in!XML/RDF!(Carver!2013;!Carver!&!Lang!2013).!Other!projects!that!employed!the! STELLAR!toolkit!for!Linked!Data!generation!were!Colonisation!of!Britain!(digitisation!and!semantic! enhancement! of! a! major! research! archive)125!and! the! SKOSification! of! the! thesaurus! used! with! ZENON,!the!online!public!access!catalog!of!the!German!Archaeological!Institute!(Romanello!2012).! 6.3.5 Need&to&integrate&shared&vocabularies&into&data&recording&tools& We!will!also!need!to!see!more!progress!with!regard!to!integrating!Linked!Data!vocabularies!in!data! recording!tools.!It!is!widely!held!that!archaeologists!exhibit!an!aversion!to!use!unfamiliar!semantics! and!prefer!to!develop!their!own!vocabulary.!The!argument!typically!is!that!this!is!necessary!because! of! their! specific! research! questions.! Frederick! W.! Limp! even! thinks! that! “the! reward! structure! in! archaeological!scholarship!provides!a!powerful!disincentive!for!participation!in!the!development!of! semantic! interoperability! and,! instead,! privileges! the! individual! to! develop! and! defend! individual! terms/structures!and!categories”!(Limp!2011:!278).! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 122!STELLAR!-!Semantic!Technologies!Enhancing!Links!and!Linked!Data!for!Archaeological!Resources!project!(UK,! AHRC-funded!project,!2010-2011),!http://hypermedia.research.southwales.ac.uk/kos/stellar/! 123!Hypermedia!Research!Unit,!University!of!South!Wales:!STELLAR!Applications,! http://hypermedia.research.southwales.ac.uk/resources/STELLAR-applications/!! 124!ArcheoInf!project,!http://www.ub.tu-dortmund.de/archeoinf/!! 125!Archaeogeomancy.net!(2014):!Colonisation!of!Britain,!30!May!2014,! http://www.archaeogeomancy.net/2014/05/colonisation-of-britain/!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!67!January!2017! ! The! reticence! to! use! vocabularies! that! are! based! on! semantic! standards! is! augmented! by! a! perception!that!this!can!be!difficult,!time!consuming!and!have!no!immediate!practical!benefit.!The! team!of!Open!Context!in!the!development!their!archaeological!data!publication!platform!collected! views! and! practical! experiences! of! many! archaeologists,! cultural! resource! management! professionals,! museum! curators! and! others.! The! results! across! all! participants! suggested! “little! motivation!or!interest!in!having!researchers!‘markup’!their!own!data!to!align!these!data!with!more! general!Web!or!semantic!standards”.!Rather!project!participants!“generally!saw!this!as!a!somewhat! abstract! goal,! disconnected! from! their! immediate! needs,! and! usually! felt! such! semantic! and! standards!alignment!stood!too!far!outside!of!their!area!of!expertise”!(Kansa!&!Whitcher-Kansa!!2011:! 5-6).!! The! Federated! Archaeological! Information! Management!Systems! project! (FAIMS,! Australia)! in! workshops! with! potential! users! found! that! archaeologists!would! appreciate! tools! that! allow! high! flexibility!and!customization!to!accommodate!their!established!research!practices.!Little!enthusiasm! was!perceived!for!adopting!common!data!standards!and!terminology,!e.g.!to!record!an!agreed!set!of! attributes!about!excavation!contexts!or!artefacts!(Ross!et!al.!2013:!111-114).!! The!results!made!the!FAIMS! team!rethink!their!approach!to!semantic! interoperability,! which! was! initially!planned!to!build!around!a!stable!(if!extensible)!core!of!data!standards,!data!schemata!and! user!interfaces.!To!accommodate!both!flexibility!and!interoperability,!FAIMS!mobile!data!recording! software!now!provides!sophisticated!tools!to!map!data!to!shared!vocabularies!as!it!is!created.!As! they!describe!the!tools,!“Using!an!approach!borrowed!from!IT!localization,!interface!text,!including! the! names! of! entities! (e.g.,! ‘stratigraphic! unit’),! attributes! (e.g.,! ‘soil! color’),! and! controlledvocabulary! values! (‘Munsell! 5YR’),! can! be! saved! and! exported! using! widely-shared! terminology! (including!uniquely!identified!terms!in!an!ontology)!but!displayed!using!the!preferred!language!of!an! individual!project!(e.g.,!‘stratigraphic!unit’!can!display!as!‘context’).!Second,!open-linked!data!URIs! can!be!embedded!in!all!entities,!attributes,!and!controlled-vocabulary!values!(linking,!e.g.,!species!to! the! Encyclopedia! of! Life,!or!places! to! Pleiades).! Finally,! data! can! be! systematically! transformed! or! amplified!during!export,!a!final!opportunity!for!mapping!to!shared!ontologies!or!linking!to!URIs.!These! approaches!balance!the!flexibility!required!by!archaeologists!with!the!ability!to!produce!interoperable! data”!(Ross!2015).! Similar! tools! are! necessary! for! describing! data! recorded! in! laboratory! work.! One! such! tool! is! RightField126.! The! open! source! tool! (implemented! in! Java)! has! been! developed! at! the! School! of! Computer!Science,!University!of!Manchester!(UK)!together!with!other!bioinformatics!research!groups! (Wolstencroft!et!al.!2011;!Wolstencroft!2012).!RightField!allows!scientists!easy!semantic!annotation! of!spreadsheet!data!with!common!vocabulary!of!their!area!of!research!using!simple!drop-down!lists.! For! each! annotation! field,! a! range! of! allowed! terms! from! a! chosen! vocabulary! can! be! specified.! Vocabularies!can!either!be!imported!from!a!local!system!or!a!registry/repository!of!vocabularies!in! SKOS,! RDFS! or! OWL! (e.g.! the! BioPortal! for! biological! vocabularies).! The! generated! semantic! information!(and!its!provenance)!is!all!held!within!the!spreadsheet.!Data!sharing!initiatives!can!use! RightField!to!generate!and!distribute!a!spreadsheet!template!to!laboratory!scientists!and!collect!and! integrate!the!data!and!semantic!annotations.!! ! ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 126!RightField,!http://www.rightfield.org.uk!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!68!January!2017! ! 6.3.6 Brief&summary&and&recommendations& Brief&summary&& Showcase!examples!of! Linked! Data! applications! in! the! field! of! cultural! heritage! (e.g.! museum! collections)!so!far!depended!heavily!on!the!support!of!experts!who!are!familiar!with!the!Linked!Data! methods! and! required! tools! (often! their! own!tools).! But! such! know-how! and! support! is! not! necessarily!available!for!the!many!cultural!heritage!and!archaeology!institutions!and!projects!across! Europe.!A!much!wider!uptake!of!Linked!Data!will!require!approaches!that!allow!non-IT!experts!(e.g.! subject!experts,!curators!of!collections,!project!data!managers)!do!most!of!the!work!with!easy!to!use! tools!and!little!training!effort.!! A!number!of!projects!have!reported!advances!in!this!direction!based!on!the!provision!of!useful!data! mapping! recipes! and! templates,! proven! tools,! and! guidance! material.! ! For! example,! the! STELLAR! Linked!Data!toolkit!has!been!employed!in!several!projects!and!appears!to!be!useable!also!by!nonexperts!with!little!training!and!additional!advice.!! Good! tutorials! and! documentation! of! projects! are! helpful,! but! the! need! for! expert! guidance! in! various!matters!of!Linked!Open!Data!is!unlikely!to!go!away.!For!example,!there!are!a!lot!of!immature,! not!tried!and!tested!software!tools!around.!Therefore!advice!of!experts!is!necessary!on!which!tools! are!really!proven!and!effective!for!certain!tasks,!and!providers!of!such!tools!should!offer!practical! tutorials!and!hands-on!training,!if!required.!Experienced!practitioners!can!also!help!projects!navigate! past!dead!ends!and!steer!project!teams!toward!best!practices.! Also!more!needs!to!be!done!with!regard!to!integrating!Linked!Data!vocabularies!in!tools!for!data! recording! in! the! field! and! laboratory.! Like! other! researchers! archaeologists! typically! show! little! enthusiasm! to! adopt! unfamiliar! standards! and! terminology,! which! is! perceived! as! difficult,! timeconsuming,!and!may!not!offer!immediate!practical!benefits.!! Proposed!tools!therefore!need!to!fit!into!normal!practices!and!hide!the!semantic!apparatus!in!the! background,! while! supporting! interoperability! when! the! data! is! being! published.! Noteworthy! examples!are!the!FAIMS!mobile!data!recording!tools!and!the!RightField!tool!for!semantic!annotation! of!laboratory!spreadsheet!data.!! Recommendations! o Focus!on!approaches!that!allow!non-IT!experts!do!most!of!the!work!of!Linked!Data!generation,! publication!and!interlinking!with!little!training!effort!and!expert!support.! o Provide! useful! data! mapping! recipes! and! templates,! proven! tools! and! guidance!material! to! enable!reducing!some!of!the!training!effort!and!expert!support!which!is!still!necessary!in!Linked! Data!projects.!! o Steer!projects!towards!Linked!Data!best!practices!and!provide!advice!on!which!methods!and!tools! are!really!proven!and!effective!for!certain!data!and!tasks.! o Current!practices!are!very!much!focused!on!the!generation!of!Linked!Data!of!content!collections.! More! could! be! done! with! regard! to! integrating! Linked! Data! vocabularies! in! tools! for! data! recording!in!the!field!and!laboratory.!! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!69!January!2017! ! 6.4 Promote&Knowledge&Organization&Systems&as&Linked&Open&Data& Knowledge! Organization! Systems!(KOSs)! such! as! ontologies,! classification! systems,! thesauri! and! others!are!among!the!most!valuable!resources!of!any!domain!of!knowledge.!Because!of!the!large! variety!of!cultural!artefacts!and!contexts!the!cultural!heritage!sector!is!particularly!rich!in!KOSs.!In!the! web! of! Linked! Data! KOSs! are! infrastructural! components! which! provide! the! conceptual! and! terminological!basis!for!consistent!interlinking!of!data!within!and!across!fields!of!knowledge.!!They! can! serve! as! bridges! which! enable! interoperability! between! dispersed! and! heterogeneous! data! resources.! Therefore! KOSs! should! be! openly! available! and! of! course! in! appropriate! Linked! Data! formats.!! Most!Linked!Open!Data!KOSs!are!being!developed!from!existing!systems.!The!development!requires! collaboration! of! domain! and! technical! experts,! or! domain! experts! with! the! required! mix! of! knowledge!and!skills.!As!John!Unsworth!once!put!it!for!KOSs!in!general,!“In!some!form,!the!semantic! web! is! our! future,! and! it! will! require! formal! representations! of! the! human! record.! Those! representations!–!ontologies,!schemas,!knowledge!representations,!call!them!what!you!will!–!should! be!produced!by!people!trained!in!the!humanities.!Producing!them!is!a!discipline!that!requires!training! in!the!humanities,!but!also!in!elements!of!mathematics,!logic,!engineering,!and!computer!science.!Up! to!now,!most!of!the!people!who!have!this!mix!of!skills!have!been!self-made,!but!as!we!become!serious! about!making!the!known!world!computable,!we!will!need!to!train!such!people!deliberately.!There!is!a! great!deal!of!work!for!such!people!to!do!–!not!all!of!it!technical,!by!any!means.!Much!of!this!mapmaking!will!be!social!work,!consensus-building,!compromise.!But!even!that!will!need!to!be!done!by! people! who! know! how! consensus! can! be! enabled! and! embodied! in! a! computational!medium.! Consensus-based! ontologies! (in! history,! music,! archaeology,! architecture,! literature,! etc.)! will! be! necessary,!in!a!computational!medium,!if!we!hope!to!be!able!to!travel!across!the!borders!of!particular! collections,!institutions,!languages,!nations,!in!order!to!exchange!ideas”!(Unsworth!2002).! 6.4.1 Knowledge&Organization&Systems&(KOSs)& Knowledge! organization! systems! (KOSs)! can! take! different! forms,! e.g.! glossary,! thesaurus,! classification!scheme,!ontology!(Souza!et!al.!2012;!Bratková!&!Kučerová!2014).!A!KOS!may!be!used!by! institutions!in!many!countries,!mainly!in!one!country!or!as!a!“home-grown”!vocabulary!only!by!one! institution.!Most!KOSs!are!being!used!as!controlled!vocabularies!to!select!preferred!terms,!names!or! other! “values”! for! certain! fields! of! metadata!records.! For! example,! a! subjects! thesaurus! provides! terms!for!the!subjects!of!documents!or!a!gazetteer!provides!names!and!geo-coordinates!for!places.! An! ontology! provides! a! conceptual! model! of! a! domain! of! knowledge! (e.g.! the! CIDOC!Conceptual! Reference!Model).! Some!years!ago!many!KOSs!were!still!made!available!as!copyrighted!manuals!in!PDF!format!or!as! simple!online!lookup!pages.!Recently!open!licensing!of!KOSs!has!become!the!norm!and!ever!more! existing!KOSs!are!being!prepared!and!published!as!Linked!Open!Data!for!others!to!re-use.!! The! RDF! family! of! specifications! provides! “languages”! for! KOSs! such! as! Simple! Knowledge! Organization!System!(SKOS),!RDF!Schema!(RDFS)!and!Web!Ontology!Language!(OWL).!The!relatively! lightweight! language! SKOS127!can! be! used! to! transform! a! thesaurus,! taxonomy! or! classification! system!to!Linked!Data;!it!can!of!course!also!be!used!to!build!a!new!KOS,!if!necessary.!Released!as!a! W3C!recommendation!in!2009,!the!language!has!been!adopted!by!many!KOS!owners/developers!to! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 127!W3C!(2009)!Recommendation:!SKOS!Simple!Knowledge!Organization!System,!18!August!2009,! https://www.w3.org/2004/02/skos/!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!70!January!2017! ! transform! (“SKOSify”)! controlled! vocabularies! for! use! in! the! web! of! Linked! Data.! KOSs! that! are! complex! conceptual! reference! models! (or! ontologies)! of! a! domain! of! knowledge! are! typically! expressed!in!RDF!Schema!(RDFS)128!or!the!Web!Ontology!Language!(OWL)129.! KOSs! in! the! mentioned! languages! are! machine-readable! which! allows! various! advantages.! For! example! a! SKOSified!thesaurus!employed! in!a!search!environment!can!enhance!search!&!browse! functionality! (e.g.! facetted! search! with! query! expansion),! while! Linked! Data! ontologies! can! allow! automated!reasoning!over!semantically!linked!data.! 6.4.2 Cultural&heritage&vocabularies&in&use& Before!looking!into!the!development!of!cultural!heritage!and!archaeological!KOSs!as!Linked!Data!it! will!be!good!to!have!a!view!on!the!current!used!of!KOSs!in!these!fields.!For!cultural!heritage!a!study! of!the!AthenaPlus!project!gives!an!impression,!and!for!archaeology!the!varity!of!vocabulary!usage!by! ARIADNE!data!partners!may!be!indicative!for!the!situation.! AthenaPlus&study&of&vocabularies&in&use&& AthenaPlus!(2013a)!collected!and!analysed!information!on!52!cultural!heritage!vocabularies!that!are! in!use!at!33!organisations!in!Europe.!The!main!results!of!the!study!can!be!summarised!as!follows:!! o Most! of! the! vocabularies! are! thesauri! or! classification! systems! with! a! more! or! less! complex! hierarchical! structure.! Some! are! flat! lists! of! terms! which! may! combine! terms! from! different! terminologies.! o Most!of!the!organisations!use!an!own!vocabulary!developed!in-house,!often!with!no!reference!to! standards!(e.g.!ISO!thesauri!standards)130;!this!group!includes!national-level!organisations.! o Multi-lingual! vocabularies! are! rare,! only! a! few! vocabularies! have! concepts! in! more! than! one! language.! o The!vocabularies!are!mainly!used!for!indexing!and!as!a!query!feature!of!an!online!database.! o Most!vocabularies!have!unique!identifiers!for!the!concepts,!and!only!few!management!systems! do!not!allow!to!export!them!from!the!local!dabase!(e.g.!in!a!CSV-file).! o The! situation! concerning! copyrights! (licensing)! is! varied,! some! vocabularies! are! free! of! rights,! some! organisations! apply! a! Creative! Commons! license,! others! have! not! sought! to! clarify! copyrights!yet.!! Some!of!the!vocabularies!may!be!used!by!archives!and!museums!that!hold!archaeological!artifacts! among!other!cultural!heritage!objects,!but!few!seem!to!be!relevant!for!archaeological!research!data! sets!due!to!lack!of!specific!terms!for!this!domain.! Vocabulary&use&by&ARIADNE&partners& The! pattern! of! vocabulary! use! by!ARIADNE! data! partners! is! roughly! similar! to! the! results! of! the! AriadnePlus!study!(cf.!ARIADNE!2013):! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 128!W3C!(2014)!Recommendation:!RDF!Schema!1.1,!25!February!2014,!http://www.w3.org/TR/rdf-schema/!! 129!W3C!(2012)!Recommendation:!OWL!2!Web!Ontology!Language!Document!Overview!(Second!Edition),!11! December!2012,!https://www.w3.org/TR/2012/REC-owl2-overview-20121211/!! 130!ISO!thesauri!standards:!ISO!2788:1974/1986!(monolingual),!ISO!5964:1985!(multilingual),!or!ISO!259641/2:2011!(thesauri!and!interoperability!with!other!vocabularies).! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!71!January!2017! ! o Three!partners!use!international!and/or!multi-lingual!vocabularies!(more!than!two!languages):!! - European!Language!Social!Science!Thesaurus!(ELSST)131,!! - General! Multilingual! Environmental! Thesaurus! (GEMET)132!and! part! of! the! Tree!of! Life! taxonomy!for!wood!species133,!! - PACTOLS!thesaurus!(multi-lingual)134.! o Four!partners!use!national!standard!vocabularies! - Geological!Survey!of!Ireland!(classifications!for!geology,!petrology!and!soils)135,!Placenames! Database! of! Ireland136,! Irish! National! Monuments! Service! monument! class! list137,! Artefact! classification138,!! - Swedish!Monument!type!vocabulary139,!! - Archeologisch!Basisregister!(ABR,!Netherlands)140,! - PICO!thesaurus141!and!SITAR!vocabularies!(Italy)142.!! o Seven!partners!use!proprietary!controlled!vocabularies!(thesauri,!term!lists),!! o Three!partners!currently!do!not!use!controlled!vocabularies.! Some!of!the!vocabularies!mentioned!are!already!available!in!SKOS!(e.g.!GEMET!since!many!years)!or! such!a!version!is!in!preparation!(see!below).!! 6.4.3 Development&of&KOSs&as&Linked&Open&Data& The!first!generation!of!cultural!heritage!Semantic!Web!projects!(started!about!15!years!ago)!often! used!major!vocabularies!such!as!the!Getty!thesauri,!Iconclass!(Netherlands!Institute!for!Art!History)! and!others!for!“research!purposes”,!i.e.!without!allowance!to!share!publicly!vocabulary!Linked!Data! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 131!ELSST!is!a!broad-based,!multilingual!thesaurus!for!the!social!sciences.!It!is!currently!available!in!12! languages:!Czech,!English,!Danish,!Finnish,!French,!German,!Greek,!Lithuanian,!Norwegian,!Romanian,! Spanish!and!Swedish,!http://elsst.ukdataservice.ac.uk!! 132!GEMET!(EIONET/European!Environment!Agency),!http://www.eionet.europa.eu/gemet/!! 133!Tree!of!Life!(TOL)!project,!http://tolweb.org/tree/!! 134!PACTOLS!-!Peuples,!Anthroponymes,!Chronologie,!Toponymes,!Oeuvres,!Lieux!et!Sujets!(Fédération!et! ressources!sur!l’Antiquité!(FRANTIQ,!France),!http://pactols.frantiq.fr!! 135!Geological!Survey!of!Ireland,!http://www.gsi.ie!! 136!Placenames!Database!of!Ireland,!http://www.logainm.ie/en/!! 137!Irish!National!Monuments!Service!monument!class!list,! http://webgis.archaeology.ie/NationalMonuments/WebServiceQuery/Lookup.aspx!! 138!National!Museum!of!Ireland:!Artefacts,!http://www.museum.ie/en/list/artefacts.aspx!! 139!See!http://www.fmis.raa.se!(lämningstyp)!and!Swedish!National!Heritage!Board!(2014),!extended!by!the! Swedish!National!Data!Service!(SND)!with!keywords!researchers!use!when!depositing!data!with!SND.! 140!Archeologisch!Basisregister!(Cultural!Heritage!Agency!of!the!Netherlands),! http://cultureelerfgoed.nl/dossiers/archis-30/archeologisch-basisregister-plus!! 141!PICO!thesaurus!(Central!Institute!for!the!Union!Catalogue!-!ICCU,!Italy;!terms!in!Italian!and!English,!but!not! archaeology-specific),!http://purl.org/pico/thesaurus_4.2.0.skos.xml!! 142!SITAR!Project!Data!Model!&!DataSet!(Soprintendenza!Speciale!per!i!Beni!Archeologici!di!Roma),! https://www.academia.edu/5029017/MiBACTSSBAR_SITAR_Project_Data_Model_presentation_at_the_ARIADNE_Workshop_in_Pisa_7-8.11.2013_!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!72!January!2017! ! they!produced!from!parts!of!such!resources.!The!move!to!Open!and!Linked!Data!vocabularies!was! initiated! by! the! library! community,! for! example! the! US! Library! of! Congress! (since! 2009)143,! OCLC! (worldwide!library!cooperative)144!and!others.!In!recent!years!the!owners!of!major!vocabularies!for! the!humanities!and!cultural!heritage!followed.!! In! 2012! Iconclass,! the! widely! used! classification! system! for! visual! content! of! cultural! works! (e.g.! iconography),!was!made!available!as!Linked!Open!Data145.!In!2014/2015!the!Getty!Research!Institute! released! three! of! their! vocabularies! as! Linked! Open! Data:!Art! &! Architecture! Thesaurus! (AAT),! Thesaurus!of!Geographic!Names!(TGN)!and!Union!List!of!Artist!Names!(ULAN);!the!Cultural!Objects! Name!Authority!(CONA)!was!intended!to!follow!in!Fall!2015!but!seems!to!require!more!effort!than! expected.146!! In!the!UK!the!SENESCHAL!project!(2013-2014)147!transformed!several!cultural!heritage!vocabularies! of! English! Heritage,! Royal! Commission! on!the! Ancient! and! Historical! Monuments! of! Scotland! (RCAHMS)!and!Royal!Commission!on!the!Ancient!and!Historical!Monuments!of!Wales!(RCAHMW)!to! SKOS! and! made! them! available! online148!(Binding! &! Tudhope! 2016).! SENESCHAL! built! on! the! experience!and!tools!developed!in!the!STAR!and!STELLAR!projects!(2007-2011)149.!The!goal!of!the! project!was!to!make!it!easier!for!vocabulary!providers!to!publish!their!vocabularies!as!Linked!Data! and!for!users!to!index!their!data!with!uniquely!identified!terms!of!the!SKOSified!vocabularies.!The! project!developed!RESTful!web!services!that!facilitate!concept!searching,!browsing,!suggestion!and! validation.! Furthermore! browser-based! widgets! (predefined! user! interface! controls)! are! available! that!allow!for!embedding!the!vocabularies!in!web!pages!and!web!forms!to!better!index!data!and! improve!search!applications.!! Many!others!have!also!already!transformed!their!vocabularies!to!SKOS!or!developed!new!ones!based! on!the!standard.!Some!examples!relevant!for!archaeological!data!are:!The!PACTOLS!thesaurus150!of! the! Fédération! et! ressources! sur! l’Antiquité! (FRANTIQ),! France,! is! a! multi-lingual! thesaurus! that! focuses!on!antiquity!and!archaeology!from!prehistory!to!the!industrial!age!(terms!in!French,!English,! German,!Italian,!Spanish,!Dutch,!and!some!Arabic).!! In!the!Netherlands!the!Rijksdienst!Cultureel!Erfgoed!(Cultural!Heritage!Agency)!have!produced!SKOS! versions!of!their!Archeologisch!Basisregister!(ABRr+)!and!other!thesauri151.!Some!of!them!have!been! used!in!ARIADNE!to!explore!the!extraction!of!(meta-)data!from!Dutch!fieldwork!reports!based!on! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 143!Library!of!Congress:!Linked!Data!Service,!http://id.loc.gov;!Library!of!Congress!Subject!Headings!(LCSH),! MARC!Code!Lists,!Thesaurus!of!Graphic!Materials,!AFS!Ethnographic!Thesaurus!and!others.! 144!OCLC!(worldwide!library!cooperative):!Linked!Data,!http://oclc.org/developer/develop/linked-data.en.html;! available:!Dewey!Decimal!Classification!(DDC),!Virtual!International!Authorities!File!(VIAF),!Faceted! Application!of!Subject!Terminology!(FAST)!and!WorldCat.! 145!Iconclass!as!Linked!Open!Data,!http://www.iconclass.org/help/lod!! 146!Getty!Vocabularies!as!Linked!Open!Data,!http://www.getty.edu/research/tools/vocabularies/lod/index.html!!! 147!SENESCHAL!-!Semantic!Enrichment!Enabling!Sustainability!of!Archaeological!Links!(UK,!AHRC-funded!project,! 2013-2014),!http://hypermedia.research.southwales.ac.uk/kos/seneschal/!! 148!HeritageData,!http://www.heritagedata.org!! 149!STAR!-!Semantic!Technologies!for!Archaeological!Resources!(UK,!AHRC-funded!project,!2007-2010),! http://hypermedia.research.southwales.ac.uk/kos/star/;!STELLAR!-!Semantic!Technologies!Enhancing!Links! and!Linked!Data!for!Archaeological!Resources!(UK,!AHRC-funded!project,!2010-2011),! http://hypermedia.research.southwales.ac.uk/kos/stellar/!! 150!PACTOLS!(Peuples,!Anthroponymes,!Chronologie,!Toponymes,!Œuvres,!Lieux!et!Sujets),! http://pactols.frantiq.fr!! 151!Rijksdienst!Cultureel!Erfgoed:!Erfgoedthesaurus,!http://www.erfgoedthesaurus.nl!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!73!January!2017! ! named!entity!recognition!(ARIADNE!2015c).!In!Sweden!the!Riksantikvarieämbetet!(National!Heritage! Board)!aims!to!translate!their!vocabularies!(e.g.!the!Swedish!monuments!types!thesaurus)!to!SKOS! and! release! them! as! Linked! Open! Data.! This! work! is! under! way! in! their!Digital! Archaeological! Workflow!programme,!2013-2018!(Smith!2015:!219).!!! Examples! of! Linked! Data! vocabularies! for! research! specialities! are! the! Nomisma! ontology! for! numismatics152,! the! set! of! vocabularies! for!epigraphy! developed! by! the! EAGLE! project153,! and! the! multi-lingual!vocabulary!for!dendrochronological!data!based!on!the!Tree!Ring!Data!Standard!(TRiDaS)! standard154.!The!vocabuarly!has!been!developed!by!Data!Archiving!and!Networked!Services!(DANS,! Netherlands),! with! support! by! ARIADNE.! The! vocabulary! is! being! employed! for! the! Digital! Collaboratory!for!Cultural!Dendrochronology155!(Jansma!2013)!and!available!also!to!other!users.! As!the!case!of!dendrochronology!reminds!us,!Linked!Data!vocabularies!for!archaeological!data!are!of! course!not!limited!to!cultural!artefacts.!Such!vocabularies!are!also!needed!for!describing!biological! remains!of!humans,!animals!and!plants.!There!are!many!relevant!biological!vocabularies!available!in! Linked! Data! formats! shared! on! the! BioPortal156,! and! may! increasingly! be! used! by! archaeological! institutions!and!projects!to!integrate!datasets.!One!example!is!a!project!that!employed!concepts!of! the!Uber!Anatomy!Ontology!(UBERON)157!for!zooarchaeological!data!(Kansa!et!al.!2014;!WhitcherKansa!2015).! An!interesting!case!where!a!vocabulary!of!an!established!system!is! being! transformed! to! SKOS!is! TAXREF,!the!French!national!taxonomic!reference!for!fauna,!flora!and!fungus!(Callou!et!al.!2015).! TAXREF! is! being! used! for! the! National! Inventory! of! Natural! Heritage! (INPN)158,! and! the! Archaeozoological!and!Archaeobotanical!Inventories!of!France!(I2AF)!database159!(Callou!et!al.!2009! and!2011).!TAXREF!and!the!databases!are!maintained!by!the!French!National!Museum! of!Natural! History!(MNHN),!the!I2AF!in!collaboration!with!a!multi-institute!network!of!bioarchaeologists160.!! In!addition!to!publishing!TAXREF!in!SKOS!it!is!intended!to!set!up!a!Web!service!allowing!to!query!the! taxonomy!and!retrieve!results!in!different!formats!such!as!XML/RDF!and!JSON.!Furthermore!there! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 152!Nomisma!ontology,!http://nomisma.org/ontology!! 153!EAGLE!vocabularies!(Material,!Type!of!inscription,!Execution!technique,!Object!type,!Decoration,!Dating! criteria,!State!of!preservation),!http://www.eagle-network.eu/resources/vocabularies/!! 154!Tree!Ring!Data!Standard!(TRiDaS),!vocabularies:!http://www.tridas.org/vocabularies/!! 155!Digital!Collaboratory!for!Cultural!Dendrochronology!-!DCCD,!http://dendro.dans.knaw.nl,!see!also:! https://vkc.uu.nl/vkc/dendrochronology/!!! 156!BioPortal!(US!National!Center!for!Biomedical!Ontology),!https://bioportal.bioontology.org! 157!UBERON!-!Uber!Anatomy!Ontology!(http://uberon.org)!is!a!cross-species!anatomy!ontology!that!represents! body!parts,!organs!and!tissues!in!a!variety!of!animal!species,!with!a!focus!on!vertebrates;!it!includes! relationships!to!taxon-specific!anatomical!ontologies,!allowing!integration!of!functional,!phenotype!and! expression!data;!see!Mungall!et!al.!(2012).!! 158!Inventaire!National!du!Patrimoine!Naturel!/!National!Inventory!of!Natural!Heritage!(Muséum!national! d’Histoire!naturelle),!http://inpn.mnhn.fr!! 159!Inventaires!archéozoologiques!et!archéobotaniques!de!France!(I2AF),! https://inpn.mnhn.fr/espece/inventaire/I100!! 160!GDR!3644!BioArchéoDat,!Sociétés,!biodiversité!et!environnement:!données!et!résultats!de!l’archéozoologie! et!de!l’archéobotanique!sur!le!territoire!de!la!France,!http://archeozooarcheobota.mnhn.fr/spip.php?article236&lang=fr!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!80!January!2017! ! While! different! approaches! are! being! used,! the! quality! criteria! essentially! are! about! how! users! (humans!and!machines)!can!discover,!understand!and!access!Linked!Data!resources!that!are!wellstructured,!accurate,!up-to-date!and!reliable!over!time.!Ideally!the!result!of!the!current!efforts!will!be! easy!to!use!tools!that!allow!Linked!Data!curators!monitor!resources,!detect!and!fix!problems!so!that! high-quality!webs!of!data!are!being!developed!and!maintained.!! 6.5.4 Foster&a&community&of&archaeological&LOD&curators& The! lack! of! trustworthy!resources!in! many! quarters! of! the! “web! of! data”! makes! clear! a! core! requirement! for! high-quality! Linked! Open! Data:!a! community! of! curators! who! ensure! reliable! availability!and!interlinking!of!LOD!datasets!and!vocabularies.! One!domain!of!good!Linked!Data!curation!practices!which!could!be!followed!are!the!Life!Sciences.! Ten! years! ago! the! Life! Sciences! Semantic! Web! was! described! as! full! of! “semantic! creep! –! timid,! piecemeal!and!ad!hoc!adoption!of!parts!of!standards!by!groups!that!should!be!stridently!taking!a! leadership!role!for!the!community”!(Good!&!Wilkinson!2006).!Meanwhile!the!domain!has!advanced! substantially!towards!a!more!integrated!area!of!the!web!of!LOD.!One!outstanding!example!is!the! Bio2RDF174!community!which!created!and/or!interlinked!35!datasets.!The!Bio2RDF!datasets!are!one! of!the!densest!clusters!present!on!the!LOD!diagram175.!! The! importance! of! LOD!curation! becomes! clear! when! considering! that! also! a! lot! of! life! and! biosciences!related!Linked!Data!produced!as!yet!remains!isolated!and!difficult!to!integrate.!Hasnain!et! al.!(2015)!catalogued!137!public!SPARQL!endpoints!of!relevant!Linked!Data!providers!and!tried!to!link! concepts! and! properties! of! the! resources.! They! found! that! most! resources! could!not! be! easily! mapped!because!there!was!very!little!vocabulary!and!URI!re-use,!i.e.!vocabularies!which!might!bridge! between!the!resources!were!not!present.!Also!shortcomings!of!URIs!are!noted!as!a!lot!could!not!be! deferenced!and!many!datasets!included!orphan!URIs!(i.e.!“type”-less!URI!instances).!! If!the!domain!of!archaeological!research!aspires!to!grow!a!rich!and!robust!web!of!LOD!within!the! overall! LOD! Cloud,!it! will! have! to! foster! and! support! a! community! of! curators!who! take! care! for! proper!generation,!publication!and!interlinking!of!LOD!datasets!and!vocabularies.!This!community! could!benefit!from!good!practices!demonstrated!by!the!Ancient!World!LOD!community!mobilised! and!integrated!by!Pelagios!and!research!object!centred!initiatives!such!as!Nomisma!(see!Section!5.3).! 6.5.5 Brief&summary&and&recommendations& Brief&summary!! The!core!Linked!Data!principle!arguably!is!that!publishers!should!link!their!data!to!other!datasets,! because! without! such! linking! there! is! no! “web! of! data”.! In! practice! this! principle! is! often! not! followed,! particularly! also! not! in! the! field! of! cultural! heritage! and! archaeology.! This! means! that! already!produced!Linked!Data!remains!isolated,!a!web!of!data!has!not!emerged!yet.!There!are!several! reasons!for!this!shortcoming.!Obviously!one!factor!is!that!only!few!projects!so!far!have!produced!and! exposed!archaeological!Linked!Data.!Developers!of!such!data!will!also!not!consider!popular!Linked! Data! resources! like! DBpedia/Wikipedia! as! relevant! candidates.! Moreover! there! is! the! issue! of! reliability,!that!data!one!links!to!will!remain!accessible,!which!often!they!are!not.!Surveys!found!that! many!datasets!present!problems,!for!example!SPARQL!endpoints!are!often!off-line!or!present!errors.!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 174!Bio2RDF:!Linked!Data!for!the!Life!Sciences,!http://bio2rdf.org!! 175!Cf.!the!Linking!Open!Data!cloud!diagram,!http://lod-cloud.net!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!81!January!2017! ! With!the!increasing!number!of!Linked!Data!resources!their!quality!has!become!a!core!topic!of!the! developer! community.! Detailed! quality! schemes! and! metrics! are! being! elaborated! and! used! to! scrutinize!resources!and!suggest!improvements.!The!quality!criteria!essentially!are!about!how!users! (humans!and!machines)!can!discover,!understand!and!access!Linked!Data!resources!that!are!wellstructured,!accurate,!up-to-date!and!reliable!over!time.!Furthermore!the!resources!should!be!welldocumented,! e.g.! with! regard! to! data! provenance! and! policy/licensing.! Ideally! the! result! of! the! quality!initiative!will!be!easy!to!use!tools!that!allow!Linked!Data!curators!monitor!resources,!detect! and!fix!problems!so!that!high-quality!webs!of!data!are!being!developed!and!maintained.! The! lack! of! trustworthy!resources!in! many! quarters! of! the! “web! of! data”! makes! clear! that! a! community!of!curators!is!necessary!who!take!care!for!reliable!availability!and!interlinking!of!highquality! archaeological! LOD! datasets!and! vocabularies.! A! few! domains! already! have! such! a! community,! the! Libraries! and! Life! Sciences! domains,! for! instance.! Also! the! Ancient! World! LOD! community!around!the!Pelagios!initiative!or!the!Nomisma!community!can!be!mentioned!as!examples! of!good!practice.!It!appears!that!the!domain!of!archaeology!needs!a!LOD!task!force!and!a!number!of! projects!which!demonstrate!and!make!clear!what!is!required!for!reliable!interlinking!of!LOD.!! Recommendations& o Foster! a! community! of! LOD! curators! who! take! care! for! proper! generation,! publication! and! interlinking!of!archaeological!datasets!and!vocabularies.! o Form!a!task!force!with!the!goal!to!ensure!reliable!availability!and!interlinking!of!LOD!resources;! LOD!quality!assurance!and!monitoring!should!be!established.!! o Sponsor! a! number! of! projects! which! demonstrate! the! interlinking! and! exploitation! of! some! exemplary!archaeological!datasets!as!Linked!Open!Data.! ! 6.6 Promote&Linked&Open&Data&for&research& Archaeological!data!and!knowledge!present!a!great!challenge!for!Linked!Data.!This!challenge!stems! from!the!multi-disciplinarity!of!the!research!on!archaeological!sites!and!objects!(Vavliakis!et!al.!2012).! A!web!of!Linked!Data!based!on!cross-domain!and!domain-specific!ontologies!and!terminologies!can! allow!addressing!better!archaeological!research!questions,!which!require!integration!of!knowledge! and!data!of!different!domains.! Today!benefits!of!Linked!Open!Data!are!mainly!framed,!and!sometimes!demonstrated,!in!terms!of! advanced!search!services!based!on!the!semantic!linking!between!related!datasets.!This!may!appeal! to!cultural!heritage!institutions!as!it!allows!making!their!collections!better!discoverable!and!more! relevant!by!adding!external!contextual!information.!! While!such!search!services!are!also!important!to!researchers,!a!focus!on!data!search!arguably!does! not!strongly!promote!the!generation!of!Linked!Open!Data!of!research!datasets.!Research!groups!and! institutions! will! be! much! more! attracted! by! demonstrated! research! dividends! of! semantically! interlinked!and!integrated!data.!Such!dividends!could!for!example!result!from!combining!data!from! several!projects!in!ways!that!enable!interesting!new!lines!of!research,!or!views!on!data!from!different! disciplinary! perspectives! suggesting! interdisciplinary! approaches.! Researchers! also! need!effective! tools,!usable!by!non-IT!experts,!to!benefit!from!Linked!Data!in!the!research!process,!e.g.!explore!and! exloit!semantic!relations!between!datasets!or!between!publications!and!related!data.!! Established! ways! of! data! integration! for! research! follow! other! paradigms! than! Linked! Data.! For! example!data!shared!by!researchers!in!a!database!with!research!tools!implemented!on!top,!e.g.!the! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!82!January!2017! ! Paleobiology!Database!for!which!Fossilworks!provides!data!query!and!analysis!tools176.!Or!a!standalone! database! with! sophisticated! modelling! and! interactive! web! interfaces!such! as!ORBIS! -! The! Stanford!Geospatial!Network!Model!of!the!Roman!World177.!ORBIS!allows!calculating!the!effort!(time,! financial! expense)! associated! with! different! types! of! travel! in! antiquity!(Meeks! &! Grossner! 2012;! Scheidel!2015).!Applications!of!Linked!Open!Data!for!research!will!have!to!demonstrate!advantages! over!or!other!benefits!than!already!established!forms!of!data!integration!and!exploitation.! 6.6.1 A&Linked&Open&Data&vision&(2010)& In!2010,!Christian!Bizer,!a!leading!researcher!in!Linked!Data!methods!and!applications,!outlined!a!10! year!vision!for!“extending!the!Web!with!a!global!scientific!data!space”!(Bizer!2010).!Bizer!observed!an! increasing!adoption!of!the!Linked!Data!approach!for!sharing!library,!government!and!scientific!data,! and!a!first!generation!of!applications!that!exploit!interlinked!datasets!for!novel!information!services.! His!vision!for!the!next!10!years,!quoted!in!full,!was:! o “Linked!data!will!develop!into!the!standard!technology!of!sharing!scientific!data!on!global!scale! and!for!interconnecting!data!between!different!scientific!data!sources.! o The!emerging!Web!of!linked!data!will!contain!scientific!data!as!well!as!data!from!other!domains! and!might!become!as!omnipresent!in!our!daily!lives!as!the!classic!document!Web!is!today.! o Most!open-license!scientific!data!sets!will!be!directly! available!as!linked!data!on!the!Web.!For! extremely!large!data!sets!from!astronomy!or!physics!for!which!it!is!inefficient!to!generate!an!RDF! representation,! the! Web! of! linked! data!will! contain! detailed! metadata! that! will! enable! the! discovery!of!these!data!sets.! o All!scientific!work!environments!will!have!linked!data!import!and!export!features!and!will!provide! for! publishing! scientific! data! directly! to! the! Web! of! linked! data.! Disciplinary! repositories! of! scientific!data!as!well!as!data!archives!will!provide!linked-data!views!on!the!archived!data!and! will!thus!make!their!content!available!on!the!Web.! o Scientists!will!navigate!along!RDF!links!between!different!scientific!data!sets!as!well!as!between! publications! and! supporting! experimental! data.! They! will! use! linked-data! search! engines! to! discover!all!data!on!global!scale!that!is!relevant!to!their!question!at!hand”.! As!one!critical!requirement!for!such!Linked!Data!empowered!research!Bizer!highlighted!disciplinespecific!vocabularies!(e.g.!thesauri,!ontologies),!which! need! to! be! integrated! so! that! a! searchable! web!of!scientific!data!can!emerge.!Furthermore!he!noted! that! integration!of!Linked!Data!tools!in! scientific!work!environments!was!missing.!So!far!Bizer’s!vision!is!not!realised,!but!has!four!further! years!to!materialize!until!2020.!! 6.6.2 LOD&for&research:&The¤t&state&of&play& Efforts! for! cultural!heritage!LOD!so!far!have!been!invested! mainly!on! publishing! various!museum! collections,! often! linked! to! DBpedia/Wikipedia.! Concerning! special! collections! an! outstanding! example! is! the! numismatics! databases! that! participate! in! the! Nomisma!initiative178.! Also! a! few! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 176!Fossilworks,!http://fossilworks.org!! 177!ORBIS!-!The!Stanford!Geospatial!Network!Model!of!the!Roman!World,!http://orbis.stanford.edu!! 178!Nomisma,!http://nomisma.org/datasets;!several!coin!datasets!of!the!American!Numismatic!Society!and! institutions!in!Europe!have!been!made!available!in!RDF!format;!the!Nomisma!project!also!provides!an! ontology!for!describing!coins.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!83!January!2017! ! archaeological! datasets!have! been! published! as! Linked! Data,!for! example,! in! the! STELLAR! project! Linked! Data! of! project! archives! deposited! with! the! Archaeology! Data! Service! (ADS)179.! Special! mention! deserves! that! the! Getty! Research! Institute! has! published! their! major! cultural! heritage! thesauri! as! LOD180,! and! also! other! widely! employed! international! and! national! vocabularies! have! become!available!as!LOD,!e.g.!Iconclass181,!UK!thesauri!made!available!by!the!SENESCHAL!project182,! the!PACTOLS!thesaurus183,!and!others.!! The!last!10!years!have!seen!substantial!advances!in!LOD!know-how,!i.e.!what!is!required!to!produce,! publish!and!interlink!LOD!of!archaeological!and!cultural!heritage!collections/databases!(cf.!Hyvönen! et! al.! 2005;! Aroyo! et! al.! [eds.]! 2007;! Kollias! &! Cousins! [eds.]! 2008;! Isaksen! 2011;! Tudhope! et! al.! 2011b;!Elliott!et!al.!2014;!May!et!al.!2015).!In!total,!however,!not!many!domain!LOD!datasets!have! been!produced!and!effectively!interlinked!as!yet.!! If!there!is!a!substantial!further!increase!in!published!and!interlinked!LOD!datasets,!semantic!search! and! browse! applications! will! allow! discovery! and! retrieval! of! related! content/data.!But!such! an! advance! will!mainly! concern! data! aggregation,! search! and! access,! use! of! LOD! for! other! research! purposes!is! not! implied.! By! use! for! research! purposes! we! mean! capability! to! address! research! questions! and! validate! or! scrutinize!knowledge! claims.! The! lack! of! such! capability! has! not! gone! unnoticed!by!researchers!and!data!managers!who!expect!relevance!of!the!LOD!approach!also!in!this! direction.!! For! example! a! researcher! who! tried! using!museum! Linked! Data! sets! for! an! art! historical! study! suggests!cultural!heritage! institutions!“to!seek!out! research!uses!of! their!data,!and! not!limit! their! thinking! to! mere! aggregation! and! dissemination! (…).! Creating! LOD! is! hard! enough! for! these! institutions,!so!with!some!more!utilities!for!individual!researchers!to!take!advantage!of!the!complex! data!expressions!and!queries!offered!by!LOD,!hopefully!it!will!be!easier!for!GLAMs!to!design!their!data! offerings!to!better!support!the!kind!of!detailed!research!that!these!data!projects!keep!promising!to! enable”!(Lincoln!2016![note:!GLAMS!is!an!acronym!for!Galleries,!Libraries,!Archives!and!Museums]).! ARIADNE!colleagues!with!regard!to!employing!the!LOD!approach!in!archaeology!note:!“Important! that!these!concepts!and!technologies!continue!to!be!developed,!but!the!next!five!years!really!need!to! start!showing!its!usefulness!for!answering!research!questions.!For!example,!using!the!LD!created!by! the!Portable!Antiquity!Scheme,!the!British!Museum!and!ADS,!and!look!at!what!we!can!actually!learn! by! combining! these! datasets.! Are! they! even! compatible?! What! makes! datasets! compatible! for! interoperability?! How! compatible! must! they! be! in! order! to! generate! new! and! useful! information?! Does!interoperability!actually!confound!the!results,!as!we!don’t!understand!how!best!to!filter!it?!It’s! one!thing! to!keep! putting!LOD! out!there,!but!we! need!to! partner!in! a!focussed! way! with!domain! experts!to!start!answering!these!questions,!begin!building!best!practice!on!how!to!actually!use!LD”!(J.! Charno,!H.!Wright!and!J.!Richards,!ADS,!statement!in!the!consultation!on!the!ARIADNE!innovation! agenda).! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 179!Archaeology!Data!Service:!The!STELLAR!project,!http://archaeologydataservice.ac.uk/research/stellar/;!ADS! Linked!Open!Data,!http://data.archaeologydataservice.ac.uk! 180!Getty!Vocabularies!as!Linked!Open!Data,!http://www.getty.edu/research/tools/vocabularies/lod/;!ARIADNE! uses!their!Art!&!Architecture!Thesaurus!for!integrating!subjects!related!information.! 181!ICONCLASS!as!Linked!Open!Data,!http://www.iconclass.org/help/lod!! 182!Heritage!Data!-!Linked!Data!Vocabularies!for!Cultural!Heritage,!http://www.heritagedata.org!! 183!PACTOLS!-!Peuples,!Anthroponymes,!Chronologie,!Toponymes,!Oeuvres,!Lieux!et!Sujets,! http://frantiq.mom.fr/thesaurus-pactols!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!84!January!2017! ! Also!researchers!of!the!data!publication!platform!Open!Context!emphasise,!“Archaeologists!need!to! see!more!direct!research!applications!in!order!to!better!justify!the!added!cost!and!effort!required!to! publish!Linked!Open!Data”!(Kansa!&!Whitcher-Kansa!2013:!9;!see!also!Kansa!2015).!Open!Context!has! been!working!on!projects!with!researchers!and!institutions!that!involve!Linked!Data.!For!example,! one!project!focused!on!zooarchaeological! datasets!documenting!early! agricultural!communities!in! Anatolia.! The! datasets! have! been! made!comparable!by!linking!and!annotating!them!according!to! animal! taxa! published! by! the! Encyclopedia! of! Life184!and! to! morphological! concepts! of! the! Uber! Anatomy! Ontology185! (Kansa!et! al.! 2014;! Whitcher-Kansa! 2015).! This! is! a! rare! example! where! archaeological!data!has!been!interlinked!with!a!scientific!KOS,!although!not!supporting!research!tasks! beyond!searching!objects.! The!need!to!progress!from!LOD!based!content/data!search!to!research-focused!applications!is!also! stressed!by!the!e-science!and!linked!science!communities!that!want!to!see!LOD!support!the!process! of!research,!including!scientific!workflows,!computing!and!analysis!(Bechhofer!et!al.!2011;!Kauppinen! et! al.! 2013).! Indeed,! novel! LOD! based! models! and! applications! that! demonstrate! considerable! advances! in! research! processes! and! outcomes! may! be! decisive! in! fostering! uptake! of! the! LOD! approach!by!research!communities.!! 6.6.3 Search&vs.&research& Some! examples! will! be! useful! to! illustrate! the! difference! between! searching! archaeological! information!based!on!LOD!and!research-focused!LOD!applications.!The!Getty!Research!Institute!has! made!available!their!major!cultural!heritage!thesauri!as!LOD.!Patricia!Harpring,!Managing!Editor!of! the!Getty!Vocabulary!Program,!describes!a!scenario!where!these!vocabularies!would!aid!discovery!of! related!information:!! “Let’s!imagine!that!a!researcher!finds!an!interesting!article!online!about!the!historical!use!of!incense! burners!in!Mexico.!To!explore!the!topic!further!today!would!require!many!hours!or!days!of!research;! however,! LOD! will! enable! a! new! generation! of! search! engines! to! follow! the! links! between! data! sources! to! deliver! more! complete! answers! in! much! less! time.! In! this! use!case,! the! AAT! [Art! &! Architecture! Thesaurus]! could! provide! variant! spellings,! synonyms! in! other! languages! for! ‘incense! burners,’! and! the! narrower! concept! ‘censers’! with! its! variant! terms,! enabling! the! researcher! to! instantaneously!discover!numerous!museum!sites!and!articles!on!this!topic.!The!AAT!hierarchy!could! also! focus! the! search! on! censers! attributed! to! Pre-Columbian! cultures.! The! user! could! explore! geographic!regions!where!these!censers!were!created!through!TGN![Thesaurus!of!Geographic!Names]! place!names,!hierarchies,!and!linked!maps.!The!names!and!biographies!in!ULAN![Union!List!of!Artist! Names]!could!lead!the!user!to!pertinent!information!about!artists!and!patrons!associated!with!the! creation! of! the! censers.! CONA![Cultural! Objects! Name! Authority],! which! ideally! will! have! subject! indexing,!could!provide!links!to!photographs,!paintings,!or!even!YouTube!videos!portraying!usage!of! censers!(see!an!entertaining!video!of!a!‘monster!censer’!at!Santiago!de!Compostela,!Spain)”!(Harpring! 2014).! Achieving!this!scenario!for!a! lot!of!cultural! heritage! information! would!be!a!great!advance!in!the! discovery!of!related!information.!As!Harpring!notes,!it!would!allow!finding!more!complete!answers!to! search!questions!in!much!less!time.!However,!this!is!about!search,!not!research.! Beck!(2010)!addresses!future!research-focused!archaeological!applications!of!LOD.!One!example!is! sequences!of!pottery!styles!which!are!being!used!to!establish!a!framework!for!dating!archaeological! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 184!Encyclopedia!of!Life,!http://eol.org!! 185!UBERON!-!Uber!Anatomy!Ontology,!http://uberon.org! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!85!January!2017! ! contexts,!e.g.!stratigraphic!layers!of!an! excavation.!Beck!envisions!that!interlinked! LOD!of!pottery! classifications! and! documentation! of! excavations! would! allow! identifying! inconsistencies! in! the! published!archaeological!record.! “In! addition! to! many! other! things! pottery! provides! essential! dating! evidence! for! archaeological! contexts.!However,!pottery!sequences!are!developed!on!a!local!basis!by!individuals!with!imperfect! knowledge! of! the! global! situation.! This! means! there! is! overlap,! duplication! and! conflict! between! different! pottery! sequences! which! are! periodically! reconciled! (…).! This! is! the! perennial! process! of! lumping! and! splitting! inherent! in! any! classification! system.! Updated! classifications! and! probable! dates!allow!us!to!re-examine!our!existing!classifications.!One!can!reason!over!the!data!to!find!out! which!contexts,!relationships!and!groups!are!impacted!by!a!change!in!the!dating!sequences!either!by! proxy!or!by!logical!inference!(a!change!in!the!date!of!a!context!produces!a!logical!inconsistency!with!a! stratigraphically!related!group).!(…)!Publicly!deposited!RDF!data!should!be!linked!data:!this!means! that!all!the!primary!data!archives!are!linked!to!their!supporting!knowledge!frameworks!(such!as!a! pottery!sequence).!When!a!knowledge!framework!changes!the!implications!are!propagated!through! to!the!related!data!dynamically”.!! This! scenario! is! very!demanding! as! it! includes! machine-based! reasoning!over! LOD! pottery! classifications!interlinked!with!information!in!many!datasets!of!excavations!which!contain!dating!of! stratigraphic!layers!of!excavations!based!on!pottery!finds.!The!pottery!classification!system!(or,!more! likely,!different!systems)!would!have!to!be!available!as!Linked!Data!(based!on!SKOS!or!OWL),!and!the! pottery!based!datings!in!the!excavation!datasets!described!consistently!in!a!common!format,!and!the! datasets!of!course!also!published!as!Linked!Data.!! While! unrealistic,! the! scenario! touches! upon! crucial! issues! of! stablility! and! change! of! knowledge! frameworks.! If! they! are! “living”! frameworks! that! support! the! on-going! research! and! knowledge! creation!process,!there!is!always!some!addition!and!modification!going!on.!One!extreme!example!is! species! taxonomies! where! revisions! are! conducted! regularly! and! produce! more! or! less! intensive! “revision!shocks”!which!impact!on!the!documentation!of!species!and!even!critical!measures!such!as! species! protection! and! conservation! (Vences! et! al.! 2013).! Hepp! (2007)! addresses! conceptual! dynamics!in! domains! of! knowledge! and! the! issue! of! long! update! cycles!of! formalized! knowledge! organization!systems.!Thus!new!and!arguably!most!interesting!concepts!in!current!research!will!not! be! present! for! long! in! domain! thesauri! or! ontologies.!Furthermore! there! is! the! issue! of! different! classifications!of!the!same!research!objects!which,!ideally,!would!co-exist!in!a!knowledge!system!or! interlinked!systems!(cf.!Madsen!2004:!41,!in!the!context!of!archaeological!reference!collections).!! Visions! of! research-focused! archaeological! applications! of! LOD,! like! Beck’s! example,! expect! such! applications! to! allow! automatic! reasoning! over! a! web! of! many!interlinked! data! resources.! In! this! quasi! artificial! intelligence! scenario! Linked! Data! applications! would! identify!inconsistencies,! contradictions,! etc.! in! scientific! statements! (knowledge! claims)!or,! as! a! positive! example,! present! surprising!relationships!between!data!worth!exploring!further.!Thus!Linked!Data!applications!would! carry!out!some!tasks!that!can!be!subsumed!under!research!rather!than!search,!e.g.!detect!relevant! relationships!between!data!or!scientific!statements!that!are!contradictory.!! 6.6.4 Examples&of&research-oriented&Linked&Data&projects& There!are!already!some!Linked!Data!projects!which!aim!to!go!beyond!simple!search!functionality.!But! not!many!and!not!necessarily!in!archaeology.!We!describe!two!examples,!one!in!the!field!of!social! history!and!another!concerning!Classical!Studies.!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!86!January!2017! ! Dutch!Ships!and!Sailors186:!As!an!example!of!LOD!in!the!field!of!social!history,!the!Dutch!Ships!and! Sailors!project!has!brought!together!four!datasets!on!Dutch!maritime!history!as!five-star!Linked!Data.! End! of! March! 2014! the! Linked! Data! comprised! of! 25! million! RDF! triples,! divided! over! 33! named! graphs.!Around! 1.5!million! links! connected! the! datasets! as!well!as!linked! to!external! sources;! for! example! 180,000! links! to! external! historical! newspaper! articles! were! established! and! 2500! geographical! entities! matched! to! GeoNames! entities! (De! Boer! et! al.! 2014!and! 2015).! The! project! presented!a!number!of!examples!of!how!the!data!can!be!used!for!historical!research!on!the!socioeconomic!realities!of!the!18th!Century,!for!example!lists!of!persons!who!embarked!on!different!types! of!ships,!analysis!of!the!birth!provinces!of!sailors!on!Dutch!East!India!Company!ships!over!multiple! years,!etc.!In!a! follow-up!project!further!datasets!have!been!added!to!the!initial!Dutch!Ships!and! Sailors!Cloud!(de!Boer!&!Leinenga!2014;!Entjes!2015).! EPNet! Project187:! Aims! to! provide! historians! with! data! resources! and! tools! for! investigating! the! Roman!trade!system!based!on!Latin!and!Greek!inscriptions!on!amphoras!for!food!transportation.!In! collaboration! with! experts! of! the! history! of! the!Roman! economy! the! project! has! specified! an! ontology!of!domain!knowledge!which!represents!the!way!the!data!are!being!understood!by!scholars,! how!they!are!connected,!and!how!they!relate!to!the!literature!and!current!research!practices.!The! main!section!of!the!ontology!is!a!specialisation!of!the!CIDOC!CRM!while!other!sections!build!on!the! metadata!model!of!the!EAGLE!project!(EAGLE!2015),!EpiDoc188!for!the!encoding!of!editions!of!ancient! texts/documents! (inscriptions,! papyri,! manuscripts),! FaBiO189!for! bibliographic!references,! and! others.!The!EPNet!ontology!is!meant!to!be!“functional!to!research”,!e.g.!support!researchers!in!the! exploration!of!hypotheses!and!question!established!narratives!(Calvanese!et!al.!2015;!Calvanese!et! al.! 2016).! Initial! data! resources! are! the! rich! database!of! Roman! amphorae! and! their! associated! epigraphy! (i.e.!stamps! and! tituli)! of! the! Centre! for! the! Study! of! Provincial! Interdependence! in! Classical! Antiquity,! University! of! Barcelona190,! the! Epigraphic! Database! Heidelberg191,! and! the! Pleiades!gazetteer!and!graph!of!ancient!places192.! 6.6.5 CIDOC&CRM&as&a&basis&for&research&applications& Expectations!of!reseach-focused!applications!of!LOD!in!the!field!of!archaeology!and!other!cultural! heritage! research! often! relate! to! the! CIDOC! CRM!as! an! integrating! framework.! Oldman! (2012)! explains!that!the!Linked!Data!publication!of!the!British!Museum!online!collection!data!in!CIDOC!CRM! format! “comes! from! a! concern! that! many! Semantic! Web! /! Linked! Data! implementations! will! not! provide! adequate! support! for! a! next! generation!of! collaborative! data! centric! humanities! projects.! They! may! not! support! the! types! of! tools! necessary! for! examining,! modelling! and! discovering! relationships! between! knowledge! owned! by! different! organisations! at! a! level! currently! limited! to! more!controlled!and!localized!data-sets”.!The!ResearchSpace!project193!(led!by!the!British!Museum)!is! developing! an! online! collaborative! environment! for! humanities! and! cultural! heritage! information! sharing!and!research!that!builds!on!CIDOC!CRM!based!methods.! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 186!Dutch!Ships!and!Sailors!(Clarin!IV!project,!4/2013-3/2014),!http://dutchshipsandsailors.nl!! 187!EPNet!-!Production!and!Distribution!of!Food!during!the!Roman!Empire:!Economic!and!Political!Dynamics! (ERC!Advanced!Grant!project,!3/2014-2/2019),!http://www.roman-ep.net!! 188!EpiDoc:!Epigraphic!Documents!in!TEI!XML,!http://epidoc.sf.net!! 189!FaBiO!-!FRBR-aligned!Bibliographic!Ontology,!http://vocab.ox.ac.uk/fabio!! 190!CEIPAC!database,!http://ceipac.ub.edu!! 191!Epigraphic!Database!Heidelberg,!http://edh-www.adw.uni-heidelberg.de!! 192!Pleiades,!http://pleiades.stoa.org!! 193!ResearchSpace,!http://www.researchspace.org!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!87!January!2017! ! Oldman!(2012)!also!notes!that!since!some!years!the!CIDOC!CRM!has!been!adopted!by!many!projects! “but!it!has!also!reached!a!‘chicken!and!egg’!stage!needing!the!implementation!of!public!applications! to!clearly!demonstrate!its!unique!properties!and!value!to!humanities!research”.!This!is!about!more! than!semantic!search!of!related!content/data!based!on!the!CIDOC!CRM!or!other!ontologies.!! The!CIDOC!CRM!is!intended!to!enable!exchange!and!integration!of!scientific!documentation!of!finds,! sites!and!monuments,!at!the!level!of!detail!and!precision!required!by!researchers!of!the!heritage! sciences194.! Recent! extensions! of! the! CIDOC! CRM!cover! scientific! observation! and! argumentation! (CRMsci!and!CRMinf).!Thus!CIDOC!CRM!based!modelling!of!scientific!processes!and!documentation! of! observations! can! enable! integration! of! scientific! information! and! argumentation! (knowledge! claims).!! The! CIDOC! CRM!developer! community! invites! data! sharing! and! integration! projects! to! use! the! ontology! to! describe! the! meaning! and! context! of! their! information! objects! so! that! research! einfrastructure!and!services!can!provide!homogeneous!access!to!the!information,!in!a!way!that!retains! its! original! meaning! and! proper! context.! The! proponents! argue! that! this! is! the! way! forward! to! relevant!heritage!research!applications.!What!they!see!as!inadequate!is!the!traditional!information! aggregation! and! integration! approach! based! on! fixed! “core”! metadata! fields! which! are! artificial! generalizations!that!do!not!mediate!the!contextual!knowledge!of!the!data!providers!such!as!research! institutes!and!museums!(Doerr!&!Oldman!2013;!Oldman!et!al.!2014).! The! vision! of! the! CIDOC! CRM!developer! community! goes! well! beyond! enabling! cultural! heritage! institutions!to!provide!structured!access!to!collection!objects.!Archaeological!and!other!heritage!data! collections!/!databases!contain!a!multitude!of!facts!that!have!been!established!with!various!methods! and! in! different! contexts! of! research.! Therefore! a! common! way! to! describe! the! information! is! required!that!allows!semantic!integration!and!addressing!questions!beyond!the!local!context!of!data! creation!and!use.! This!objective!has!been!addressed!by!the!development!of!the!ARIADNE!Reference!Model!which!is! based! on! the! CIDOC! CRM!and! enhanced! or! new! extensions! (e.g.! CRMarchaeo! for! archaeological! excavations)195.! The! aim! of! semantic! integration! of! research! data! requires! that! the! participants! produce!a! conceptual! mapping! of! their! database! structures! to! the! extended! CIDOC! CRM.! The! mapping!enables!the!conversion!and!export!of!the!databases!in!a!CIDOC!CRM!compatible!RDF!format! which!can!be!shared!as!Linked!Data!on!the!Web.! The! challenge! of! enabling! effective! mappings! has! been! addressed! by! an! innovative! solution,! the! SYNERGY! Reference! Model! (Doerr!et! al.! 2014b).! SYNERGY! is! intended! as! a! modular! environment! composed! of! different! instruments! which! will! perform! individual! tasks! of! the! mapping! process,! including!also!a!knowledge!base!of!re-useable!mapping!cases.!Several!ARIADNE!have!already!used! the!Mapping!Memory!Manager196!module!of!SYNERGY!to!define!complex!correspondences!between! entities!of!their!and!other!databases!and!the!conceptual!classes!provided!by!the!extended!CIDOC! CRM!(ARIADNE!2016a;!Doerr!et!al.!2016;!Gerth!et!al.!2016).!! At! large! scale! this! approach! will! allow! reaping!the! expected! benefits! only! in!the! medium! to!long! term,!when!many!databases!are!mapped!to!the!extended!CIDOC!CRM.!However,!mapping!of!a!few! related!databases!may!demonstrate!significant!advantages!of!CIDOC!CRM!based!integration!in!the! short-term,!possibly!promoting!further!mappings.!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 194!Cf.!Definition!of!the!CIDOC!Conceptual!Reference!Model.!Version!6.1,!February!2015,!pages!i-ii,! http://www.cidoc-crm.org/docs/cidoc_crm_version_6.1.pdf!! 195!See!the!overview!and!description!of!the!CIDOC-CRM!extensions!at:!http://www.ics.forth.gr/isl/CRMext/!! 196!Mapping!Memory!Manager!-!3M!(FORTH-ICS),!http://www.ics.forth.gr/isl/3M!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!88!January!2017! ! 6.6.6 Brief&summary&and&recommendations& Brief&summary& Linked!Open!Data!based!applications!that!demonstrate!considerable!advances!in!research!processes! and! outcomes! could! be! a! strong! driver! for! a! wider! uptake! of! the! LOD! approach! in! the! research! community.!Current!examples!of!Linked!Data!use!for!research!purposes!rarely!go!beyond!semantic! search! and! retrieval! of! information.! This! has! not! gone! unnoticed! by! researchers! who! expect! relevance!of!Linked!Open!Data!also!for!generating!and!validating!or!scrutinizing!knowledge!claims.!To! allow!for!such!uses!a!tighter!integration!of!discipline-specific!vocabularies!and!effective!Linked!Data! tools!and!services!for!researchers!are!required.! Expectations!of!reseach-focused!applications!of!LOD!in!the!field!of!cultural!heritage!and!archaeology! often! relate! to! the! CIDOC! CRM!as! an! integrating! framework.! The! CIDOC! CRM!is! recognised! as! a! common! and! extendable! ontology! that! allows! semantic! integration! of! distributed! datasets! and! addressing!research!questions!beyond!the!original,!local!context!of!data!generation.!Notably,!in!the! ARIADNE! project! several! extensions! of! the! CIDOC! CRM!have! been! created! or! enhanced,! e.g.! CRMarchaeo,!an!extension!for!archaeological!excavations,!and!extensions!for!scientific!observations! and!argumentation!(CRMsci!and!CRMinf).!! To!meet!expectations!such!as!automatic!reasoning!over!a!large!web!of!archaeological!data!many! more!(consistent)!conceptual!mappings!of!databases!to!the!CIDOC!CRM!would!be!necessary.!Linked! Data! applications! then! might! demonstrate! research! dividends! such! as! detecting! inconsistencies,! contradictions,! etc.! in! scientific! statements! (knowledge! claims)! or! suggesting! new,! maybe! interdisciplinary!lines!of!research!based!on!surprising!relationships!between!data.! Recommendations& o LOD!based!applications!that!enable!advances!in!archaeological!research!processes!and!outcomes! may!foster!uptake!of!the!LOD!approach!by!the!research!community.! o LOD!based!applications!for!research!will!have!to!demonstrate!advantages!over!or!other!benefits! than!already!established!forms!of!data!integration!and!exploitation.! o Develop!LOD!based!services!that!go!beyond!semantic!search!and!retrieval!of!information!and!also! support!other!research!purposes.! o Build!on!the!CIDOC!CRM!and!available!extensions!to!exploit!conceptually!integrated!LOD.! ! ! ! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!89!January!2017! ! 7 Linked&Data&development&in&ARIADNE& The!ARIADNE!project!promotes!a!culture!of!open!sharing!and!(re-)use!of!archaeological!data!across! institutional,!national!and!disciplinary!boundaries!of!archaeological!research.!Linked!Open!Data!can! greatly!contribute!to!this!goal.!Therefore!ARIADNE!recognises!Linked!Data!as!a!key!approach!for!data! sharing!and!interoperability.!One!strand!of!the!project!work!supports!the!development!of!such!data.! The!activities!in!this!strand!of!work!concerned!! o the!metadata!of!the!datasets!registered!in!the!ARIADNE!data!catalogue,!! o vocabularies! for! the! metadata! describing! registered! datasets! (e.g.! mapping! of! existing! vocabularies,!support!for!the!generation!of!vocabularies!in!SKOS),!! o mapping!of!datasets!to!the!core!CIDOC!CRM!and!extensions!of!the!CRM!created!in!ARIADNE,!! o demonstrators! generating! and! using! Linked! Data! (e.g.! metadata! extracted! from! unstructured! data!such!as!grey!literature,!CIDOC!CRM!based!datasets),!and! o providing!access!to!ARIADNE!Linked!Data!for!external!application!developers.! Thus!the!work!mainly!centred!on!Linked!Data!related!to!data!registration,!enabling!data!integration! via!vocabularies!and!the!CIDOC!CRM!ontology,!demonstration!of!enhanced!or!new!capabilities!(e.g.! enhanced!cross-searching!of!data!resources),!and!preparing!the!ground!for!linking!of!resources!also! beyond! the! ARIADNE! pool! of! resources.! The! ARIADNE! data! catalogue! and! other! results! of! the! activities!listed!above!are!included!in!the!ARIADNE!graph!database!and!accessible!through!a!SPARQL! endpoint!(see!Chapter!8).!The!sections!below!describe!the!activities!in!greater!detail,!including!the! Linked!Data!methods!and!tools!that!have!been!applied,!enhanced!or!newly!developed!by!ARIADNE! researchers!and!developers.! 7.1 The&ARIADNE&catalogue&as&Linked&Open&Data& The!key!component!of!the!ARIADNE!e-infrastructure!is!the!dataset!registry/catalogue.!In!the!registry! data!providers!describe!their!resources!(data!sets,!collections,!etc.!)!based!on!a!common!model,!the! ARIADNE!Catalogue!Data!Model!(ACDM)197.!The!ACDM!builds!on!the!W3C’s!Data!Catalog!Vocabulary! (DCAT)198!which!has!been!designed!to!facilitate!interoperability!between!data!catalogs!published!on! the!Web.!The!ACDM!extends!DCAT!taking!account!of!requirements!of!describing!archaeological!data! resources.!The!ARIADNE!registry/catalogue!holds!metadata!of!data!resources,!the!project!does!not! collect,! store! and! curate! primary! research! data! –! which! are! tasks! of! the! data! providers! (e.g.! community!data!archives!or!institutional!repositories).!The!metadata!is!being!collected!and!enriched! with! the! MoRe! (Metadata! &! Object! Repository)! aggregator199!and! included! in! the! ARIADNE! data! catalogue.!ARIADNE!makes!the!catalogue!and!other!data!generated!in!the!project!available!as!Linked! Open! Data.! This! means! that! other! service/application! developers! can! query! the!data! as! well! as! interlink!it!with!other!LOD.!Thereby!the!ARIADNE!LOD!can!become!part!of!a!Linked!Data!“cloud”!of! archaeological!and!related!other!information!resources.! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 197!ARIADNE!Catalogue!Data!Model!(ACDM),!http://support.ariadne-infrastructure.eu!! 198!W3C!(2014)!Recommendation:!DCAT!-!Data!Catalog!Vocabulary,!16!January!2014,! http://www.w3.org/TR/vocab-dcat/! 199!MoRe!(Metadata!&!Object!Repository),!http://more.dcu.gr;!also!registration!of!single!datasets!with!the! metadata!entered!manually!is!possible.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!96!January!2017! ! from!Dutch!datasets;!however!date-range/timeline-based!search,!e.g.!10BC!to!AD40!return!Roman! results!from!Dutch!datasets!and!Iron!Age!results!from!UK!datasets.!! On! Linked! Data! for! cultural! periods! ARIADNE! collaborates! with! the! PeriodO! project220.! PeriodO! is! building!a!system!for!collecting,!organising!and!referencing!definitions!of!periods!based!on!URIs.!The! periods!are!provided!through!an!online!application!as!well!as!a!downloadable!set!of!Linked!Data.!The! PeriodO!approach!is!to!gather!individual!period!assertions!made!by!authoritative!scholarly!sources! about!the!temporal!and!spatial!boundaries!of!periods!in!particular!research!contexts,!retaining!the! provenance!of!the!assertions,!e.g.!scholarly!book!or!paper!(Rabinowitz!2014;!Golden!&!Shaw!2015! and!2016).! But! the! PeriodO! system! also! includes! established! national! periodizations.! ARIADNE! has! produced! from!available!periodizations!a!set!of!cultural!periods!and!their!time!ranges!from!the!Paleolithic!to! Modern! times!for! 24! European! countries!(in! total! 659! periods)221.! The! periods! set! has! been! incorporated!in!the!PeriodO!system!which!allows!stable!linking!of!data!based!on!the!persistent!URIs! assigned!by!PeriodO.!To!use!the!PeriodO!URIs!in!ARIADNE!an!enrichment!service!is!being!developed! and! included! in! the! MoRe! aggregator! which!will!attach! the! URIs! when! processing! the! metadata! harvested!from!data!providers.!! Through!the!PeriodO!system!also!other!projects!can!use!periods!provided!by!ARIADNE!and!others.! ARIADNE! promotes! the! use! of! PeriodO! URIs! to! allow! for! wider! interlinking! of! data! based! on! periods/chronologies.!The! PeriodO! project! is! funded! until! 2018! by! a! grant! of! the! US! Institute! of! Museum!and!Library!Services.! 7.4 Use&of&vocabularies&in&NLP&and&data&mining& Vocabularies!are!also!important!in!natural!language!processing!and!data!mining!tasks.!The!sections! below!describe!such!uses!in!research!and!development!carried!out!in!ARIADNE.! 7.4.1 Natural&Language&Processing& In!ARIADNE!also!research!and!development!on!Natural!Language!Processing!(NLP)!of!archaeological! content! has! been! explored! with! the! aim! of! making! text-based! resources! more! discoverable! and! useful!(ARIADNE! 2015c).! This! work! of! researchers! of! the! Archaeology! Data! Service,! University! of! South!Wales!(Hypermedia!Research!Group)!and!Leiden!University!(Faculty!of!Archaeology)!focused! specifically!on!the!“grey!literature”!of!archaeological!investigations.! The!partners!have!explored!machine!learning!and!rule-based!approaches.!Here!we!focus!on!the!work! on!ruled-based!methods!in!which!vocabularies!in!Linked!Data!format!have!been!used.!In!this!work! the!OPTIMA!semantic!annotation!system!of!the!Hypermedia!Research!Group!has!been!used.!OPTIMA! performs!the!NLP!tasks!of!Named!Entity!Recognition,!Relation!Extraction,!Negation!Detection!and! Word-Sense!Disambiguation!using!hand-crafted!rules!and!terminological!resources!(Vlachidis!2012;! Vlachidis!et!al.!2013;!Vlachidis!&!Tudhope!2015a).!The!system!uses!the!GATE!(General!Architecture! for! Text! Engineering)!framework,! Ontology! Based! Information! Extraction!(OBIE)!and!several!other! techniques.!! OPTIMA! contributed! to! the! Semantic! Technologies! for! Archaeological! Research! (STAR)! project,! a! pioneer!in!the!use!of!NLP!for!extraction!of!metadata!and!linking!of!archaeological!grey!literature!and! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 220!PeriodO!-!Periods,!Organized,!http://perio.do;!see!also!https://wiki.digitalclassicist.org/PeriodO!! 221!ARIADNE!set!of!cultural!periods!in!the!PeriodO!system,!http://n2t.net/ark:/99152/p0qhb66!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!97!January!2017! ! digital!archive!databases!based!on! English!Heritage!terminology! vocabularies! and! the!CIDOC!CRM! (Tudhope!et!al.!2011b;!Vlachidis!et!al.!2012).!! The!NLP!work!in!ARIADNE!builds!upon!the!experiences!of!STAR!but!targets!“grey!literature”!also!in! other!languages.!This!faces!challenges!of!different!vocabularies!(e.g.!with!regard!to!structure)!as!well! as!differences!in!language!characteristics.!The!address!these!challenges!grey!literature!in!Dutch!has! been!chosen!using!thesauri!of!the!Rijksdienst!Cultureel!Erfgoed.!The!original!SKOSified!thesauri!were! not! suitable! for! supporting! Ontology! Based! Information! Extraction! (OBIE)! approaches,! due! to! the! incapacity! of! the! GATE! ontology! tool! to! parse! (understand)! broader/narrower! term! relationships.! Therefore!transformation!of!the!thesauri!to!OWL-Lite!(ontology)!was!necessary.!! With!regard!to!language!characteristics!particularly!compound!noun!forms!present!a!challenge!for! the! usual! “whole! word”! matching! mechanisms.! Compound! noun! forms! examples! might! include! “beslagplaat”!where!both!“beslag”!and!“plaat”!are!known!to!the!vocabulary!and!also!“aardewerkmagering”!where!aardewerk!(pottery)!is!known!but!“magering”!is!not.!! But! the! current! pilot! system! has! achieved! some! promising! semantic! enrichment! of! Dutch! grey! literature! reports,! concerning! artefacts! (such! as! “aardewerk”)! and! other! concepts! including! time! periods.!In!order!to!overcome!the!“whole!word”!restrictions!mechanisms!operating!on!part!matching! are!being!explored.!Negation!detection!is!another!aspect!that!has!been!explored!during!ARIADNE! (Vlachidis! et! al.! 2015b);! it! is! important! to! distinguish! whether!the! text! indicates! that! evidence! of! some! archaeological! issue! has!or! has!not!been! found!during!an!excavation.!Expansion! of!NLP!for! extraction,!indexing!and!linking!of!data/metadata!from!other!European!language!grey!literature!is! intended.! Critical! for! good! results! in! general! is! the! availability! of! rich! and! well-structured! vocabularies,!but!even!in!such!cases!some!modification!may!be!required!to!conduct!NLP!with!optimal! results.! 7.4.2 Mining&of&Linked&Data&& ARIADNE! partner! Leiden! University,! in! collaboration! with! the! associated! partner! Free! University! Amsterdam,!examined!the!feasibility!of!mining!archaeological!Linked!Data,!for!example,!to!detect! relevant!patterns!in!the!graph-structure!of!such!data.!! In! the! first! years! of! the! project,! started! in! February! 2013,! no! archaeological! Linked! Data! was! produced!in!the!project.!But!an!examination!of!a!few!datasets!available!elsewhere!showed!that!they! largely!consisted!of!flat!data!structures!with!descriptive!metadata!values!(ARIADNE!2015b).!Mining!of! such!data!is!unlikely!to!yield!archaeologically!interesting!patterns.!Indeed,!interviews!with!domain! experts! indicated! a! strong! interest! in!archaeological! contexts,! which! means! rich! information! generated! in! fieldwork.!Particularly! interesting! would! be! spatio-temporal! patterns! between! archaeological!contexts.!! Therefore!the!research!group!decided!to!work!on!information!in!the!Dutch!archaeological!protocol! SIKB! 0102,! called! digital! “pakbon”! (package! slip),! developed! and! maintained! by! the! Stichting! Infrastructuur! Kwaliteitsborging! Bodembeheer! (SIKB)! /! Foundation! Infrastructure! for! Quality! Assurance!of!Soil!Management222.!The!SIKB!0102!has!been!introduced!a!few!years!ago!(first!version! in!2010).!It!specifies!which!mandatory!information!about!excavations!and!finds!has!to!be!provided!as! an! XML! document!when! depositing! data!in! the! E-Depot! for! Dutch! Archaeology!(managed! by! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 222!Stichting!Infrastructuur!Kwaliteitsborging!Bodembeheer:!Protocol!0102!Archeologie,! http://sikb.nl/datastandaarden/richtlijnen/protocol-0102!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!98!January!2017! ! ARIADNE!partner!Data!Archiving!and!Networked!Services!-!DANS)223.!With!regard!to!terminology!the! thesauri! in! the! Archeologisch! Basisregister! (ABR+)! of! the! Rijksdienst! Cultureel! Erfgoed! (Cultural! Heritage!Agency)224!have!to!be!used.! While! the! amount! of! “pakbonnen”! is! growing! each! one! still! is! an! isolated! entity! and! the! XML! documents!as!such!cannot!be!used!for!semantic!integration!and!mining!of!the!information.!Therefore! the! research! group! developed!a! Linked! Data! version! of! the! SIKB! 0102!(pakbon-ld),! which! incorporates! its! set! of! archaeological! concepts! and! properties,! but! restructured! and! expanded! to! exploit!the!graph!structure225.!This!version!has!been!modelled!in!CIDOC!CRM!including!the!English! Heritage!extension!(CRM-EH)!which!contains!archaeology-specific!concepts!and!relations.!Moreover! ABR+! thesauri! in! SKOS! have! been!prepared! for! use! in! the! transformation! of! SIKB! 0102! XML! documents!to!Pakbon!Linked!Data.!Once!these!foundations!were!completed,!a!tool!for!automatic! conversion!has!been!developed226.!With!this!tool!73!SIKB!0102!XML!documents!from!the!E-Depot!for! Dutch!Archaeology!have!been!translated!and!stored!in!the!graph!database!together!with!the!CIDOC! CRM,!CRM-EH!and!ABR+!vocabularies.!! So! far! the! results! of! mining! this! resource! with! SPARQL! queries! have! been! encouraging! from! a! technical! point! of! view,! but! far! from! useful! from! an! archaeological! perspective!(e.g.! trivial! or! conflicting!results).!It!appears!that!the!detection!of!archaeologically!meaningful!patterns!requires!an! iterative!interaction!of!researchers!with!query!results!from!a!database!of!still!richer!data!than!the! “pakbonnen”!provide.!But!the!project!now!has!a!model!and!tool!for!converting!documentation!of! fieldwork!in!the!Netherlands!to!Linked!Data!and!include!it!in!the!web!of!archaeological!Linked!Data.! ! ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 223!E-depot!for!Dutch!Archaeology,!http://www.edna.nl!! 224!Rijksdienst!Cultureel!Erfgoed:!Archeologisch!Basisregister,!http://abr.erfgoedthesaurus.nl!! 225!Wilke!Xander!(VU!Amsterdam,!SPINlab):!Pakbon!Linked!Data,!http://pakbon-ld.spider.d2s.labs.vu.nl/home!! 226!Wilke!Xander!(VU!Amsterdam,!SPINlab):!Linked!Data!translation!of!the!SIKB!archaeological!protocol!0102! (aka!Pakbon),!https://github.com/wxwilcke/pakbon-ld!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!99!January!2017! ! 7.5 CIDOC&CRM&extensions&and&mappings& ARIADNE!recommends!the!CIDOC!Conceptual!Reference!Model!(CRM)227!as!a!common!ontology!for! data!integration,!discovery!and!access!based!on!Linked!Data,!including!the!more!ambitious!goal!to! support!research-oriented!applications!(see!Section!6.6.5).! The! CIDOC! CRM!has! been! developed! specifically! for! describing! and! facilitating! the! exchange! and! integration!of!cultural!heritage!knowledge!and!data.!Archaeology!partly!overlaps!with!this!domain!as! well!as!needs!modelling!of!additional!conceptual!knowledge,!for!example,!to!describe!observations! of!an!excavation!(e.g.!stratigraphy).!The!ARIADNE!Reference!Model!comprises!the!core!CIDOC!CRM! and! a! set! of! enhanced! and! new! extensions,! including! the! archaeological! excavation! process! (CRMarchaeo)!and!built!structures!such!as!historic!buildings!(CRMba).! ! ! The!table!below!gives!an!overview!of!the!extensions!to!the!CIDOC!CRM!which!have!been!created!or! enhanced!in!the!ARIADNE228:! o CRMgeo:!spatio-temporal!model!that!articulates!relations!between! the!standards!of!the!geospatial!and!the!cultural!heritage!communities! (integrates!CRM!with!OGC!standards;!applications!such!as! GeoSPARQL)! New!extension,!v1.0,! April!2013! ! o CRMdig:!model!of!digitisation!processes,!to!encode!metadata!about! the!steps!and!methods!of!production!(“provenance”)!of!digital! representations!such!as!2D,!3D!or!animated!models!(validated!in! several!projects)! Enhanced!extension,! v3.2,!August!2014! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 227!CIDOC!-!Conceptual!Reference!Model!(CIDOC-CRM),!http://www.cidoc-crm.org!! 228!Description!of!the!ARIADNE!Reference!Model!and!individual!extensions!(including!reference!document,! presentation,!RDFS!encoding)!is!available!at!http://www.ariadne-infrastructure.eu/Resources/AriadneReference-Model;!see!also!http://www.ics.forth.gr/isl/CRMext/! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!100!January!2017! ! o CRMsci:!model!for!integrating!metadata!about!scientific!observation,! measurements!and!processed!data!(validated!in!archaeology,! biodiversity!and!geology!cases)! Enhanced!extension,! v1.2.2,!August!2014! ! o CRMinf:!model!for!integrating!data!with!scholarly!argumentation!and! inference!making!in!descriptive!and!empirical!sciences!(being!validated! with!scholarly!annotations);!harmonized!with!CRMsci! New!extension,!v0.7,! February!2015! o CRMarchaeo:!model!for!integrating!metadata!about!the! archaeological!excavation!process!(introduces!concepts!of!stratigraphy! and!excavation);!being!validated!by!archaeological!records! New!extension,!v1.4,! April!2016! o CRMba:!model!for!investigating!historic!and!prehistoric!buildings,!the! relations!between!building!components,!functional!spaces,!topological! relations!and!construction!phases!through!time!and!space;! harmonized!with!CRMarchaeo! New!extension,!v1.4,! April!2016! ! o ARIADNE!Reference!Model:!CIDOC!CRM!+!set!of!new!or!enhanced! extensions! ARIADNE!Reference! Model,!v1.0,!April!2016! The!ARIADNE!Reference!Model!is!intended!to!allow!the!accurate!documentation!of!complex!entities! and! relations! of! archaeological/scientific! observations! and! analysis,! data! integration! and! search,! involving!reasoning!over!the!distributed!data!and!knowledge.!This!however!depends!on!the!interest! of!data!providers!to!map!their!databases!to!relevant!parts!of!the!conceptual!reference!model,!which! some!ARIADNE!partners!have!already!done!and!others!are!considering!(ARIADNE!2016a).! CRM&mapping&tool& A! new! tool,! the! Mapping! Memory! Manager!(3M)229!has! been! developed! by! ARIADNE! partner! Foundation!for!Research!and!Technology!Hellas,!Institute!of!Computer!Science!(FORTH-ICS,!Greece)! to! facilitate! the! mapping! of! databases! to!the! extended! CIDOC! CRM!and! the! validation! of! the! mapping;!mappings!can!be!exported!in!CRM!compliant!RDF.!The!mapping!process!is!supported!by! the!X3ML!Mapping!Framework!that!ensures!the!integrity!and!preservation!of!the!“meaning”!of!the! initial!data!(Minadakis!et!al.!2016).!! Mapping&of&databases& Several!partner!databases!(DB!schemas)!have!been!mapped!with!the!3M!tool!to!relevant!parts!of!the! extended! CIDOC! CRM.! Some! of! the! mappings! have! been! used! in! pilot! applications! which! demonstrate!advantages!of!the!extended!CRM!(see!below).!The!following!three!examples!illustrate! representative!mappings:! dFMRÖ! -! Digitale! Fundmünzen! der! Römischen! Zeit! in! Österreich!(Digital! Coin-finds! of! the! Roman! Period!in!Austria)230:!The!dFMRÖ!is!a!relational!database!of!pre-Roman!and!Roman!Imperial!period! coins!found!in!Austria!and!Romania!(75,565!records!of!coin!finds),!developed!by!the!Numismatics! Research! Group! at! the! Austrian! Academy! of! Sciences.! The! database! schema! of! the! dFMRÖ! was! mapped! to! CIDOC! CRM,! using! also! the! CRMdig! extension! and! a! specialized! extension! for! coins! covering!the!need!to!map!categorical!information!(Doerr!et!al.!2016).!The!database!provided!a!good! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 229!Mapping!Memory!Manager!-!3M!(FORTH-ICS),!http://www.ics.forth.gr/isl/3M!! 230!dFMRÖ!-!Digitale!Fundmünzen!der!Römischen!Zeit!in!Österreich!(ÖAW!Numismatic!Research!Group),! http://www.oeaw.ac.at/antike/index.php?id=358!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!101!January!2017! ! example!for!mapping!of!a!large!class!of!well-defined!traditional!databases!where!there!is!a!need!to! address!and!separate!both!categorical!and!factual!information.!Results!have!been!employed!together! with!other!datasets!in!the!coins!demonstrator.! Athenia!Agora!excavation! database:!This!database!(over!280,000!data!items)!presented!a!case!of! highly!contextualized!research!data.!The!most!relevant!parts!of!the!database!schema!were!mapped! by! a! researcher! of! the! German! Archaeological! Institute! to! CIDOC! CRM,! using! the! extensions! CRMarchaeo!and!CRMsci.!The!mapping!results!have!been!used!together!with!other!datasets!in!the! sculptures!demonstrator.! SITAR! -! Archaeological! Territorial! Informative! System! of! Rome231:! The! SITAR! system! manages! different!types!of!data!sets!including!information!about!monuments,!archaeological!finds,!survey!and! conservation!work,!archival!documents,!bibliographic!references!and!others.!A!mapping!between!the! SITAR!database!schema!and!the!concepts!of!CIDOC!CRM!and!CRMarchaeo!has!been!carried!out!by! the!ARIADNE!partner!Italian!Ministry!of!Cultural!Assets!and!Activities!(Central!Institute!for!the!Union! Catalogue)! in! cooperation! with! domain! experts! of! the! Soprintendenza! Speciale! per! il! Colosseo,! il! Museo!Nazionale!Romano!e!l’Area!Archeologica!di!Roma,!and!the!Department!of!Computer!Science! of!the!University!of!Verona.!! Also!the!ACDM!model!of!the!ARIADNE!data!registry/catalogue!has!been!mapped!to!the!CIDOC!CRM! and!a!set!of!integrated!queries!implemented!in!order!to!validate!the!adequacy!of!the!models.!This! mapping!is!being!used!to!support!data!integration!both!at!the!catalogue!and!at!the!item!level.!The! enhanced!capability!provided!by!the!ARIADNE!Reference!Model!is!being!demonstrated!in!item-level! pilot!applications.! 7.6 Demonstrators&using&CRM-based&Linked&Data& Three!pilot!applications!are!being!developed!to!demonstrate!the!capability!of!the!extended!CRM!to! support! Linked!Data! use! cases! of! item-level! data! integration,! discovery! and! access.! The! demonstrators!concern!different!objects!(coins,!sculptures,!wooden!material)!and!are!implemented! by!different!partners.!It!is!planned!to!integrate!the!pilot!demonstrators!in!the!ARIADNE!data!portal,! including!a!menu!of!exemplar!queries!for!portal!users.! The&coins&demonstrator&& The!pilot!application!has!been!led!by!FORTH-ICS!and!demonstrated!the!item-level!integration!process! of!information!about!coins!from!five!datasets!based!on!the!extended!CIDOC!CRM,!Nomisma!ontology! (numismatics! vocabularies)232!and! Art! &! Architecture! Thesaurus!(Felicetti,! Gerth! et! al.! 2016).! The! demonstrator! employed! the! core! CIDOC! CRM,! the! extension! CRMdig! and! a! small! coin-specific! extension!modelling!categorical!information.! The!following!datasets!have!been!used!in!the!demonstrator:!! o dFMRÖ!-!Digitale!Fundmünzen!der!Römischen!Zeit!in!Österreich!(Digital!Coin-finds!of!the!Roman! Period!in!Austria),!online!MySQL!database!(source:!Numismatics!Research!Group!at!the!Austrian! Academy!of!Sciences);! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 231!SITAR!-!Sistema!Informativo!Territoriale!Archeologico!di!Roma,!http://www.archeositarproject.it!! 232!Nomisma!ontology,!http://nomisma.org/ontology!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!102!January!2017! ! o MuseiD-Italia! documentation! of! several! coins! collections! of! Italian! museums! integrated! in! CulturaItalia!!(source:!Italian!Ministry!of!Cultural!Assets!and!Activities!-!Central!Institute!for!the! Union!Catalogue);! o A! subset! of! numismatics! records! (1670)! from! the! Fitzwilliam! Museum! (Cambridge)! database! prepared!in!the!COINS!project!(COINS!-!Combat!On-line!Illegal!Numismatic!Sales,!2007-2009,!see! Jarrett!et!al.!2011;!COINS!was!led!by!PIN-VastLab,!the!Coordinator!of!the!ARIADNE!project);! o Coins! data! records! (630)! from! the! Soprintendenza! Archeologica! di! Roma! (SAR)!database! –! prepared!in!the!COINS!project;! o Documentation!of!coin!finds!(517)!in!the!iDAI.field!research!database!of!the!Pergamon!project,! with! detailed! information! about! the! archaeological! context!(source:! German! Archaeological! Institute).! o Natural! Language! Processing! techniques! were! employed! by! University! of! South! Wales! (Hypermedia!Research!Group)!to!extract!numismatic!information!from!a!sample!set!of!six!reports! from!the!ADS!Grey!Literature!library!to!demonstrate!the!potential!of!NLP!for!data!integration.! The!resulting!data!was!expressed!in!the!same!CIDOC!CRM,!AAT!and!Nomisma!form!used!for!the! datasets.!It!was!successfully!integrated!into!the!FORTH-ICS!demonstrator!and!it!was!found!that! the!NLP!techniques!had!identified!items!from!the!report!text!not!explicitly!mentioned!in!the!site! record!metadata.! The!demonstrator!aimed! at!item-level! integration! of! the! diverse! coin! datasets! in! an! environment! where!users!can!effectively!query!and!receive!combined!results!coming!from!the!different!datasets.! To!enable!such!a!search!environment!four!of!the!datasets!were!mapped!with!FORTH-ICS’!Mapping! Memory! Manager! (3M)! to! the! ARIADNE! Reference! Model! and! transformed! to! RDF! format;! the! MuseiD-Italia!data! was!already!in!CIDOC-CRM!RDF!form,!compatible!with!the!ARIADNE!Reference! Model.!In!addition!mapping!of!terms!in!dataset!records!to!the!Art!&!Architecture!Thesaurus!(AAT)! and!Nomisma!ontology!(both!available!as!Linked!Data)!was!necessary!to!enable!integrated!searching! of!the!coins!documentation.!! The!pilot!application!employs!the!Blazegraph!RDF!graph!database233!and!the!user!interface!is!based! on! the! Metaphacts!platform234.! The! platform! implements! the! Fundamental! Categories! and! Relationships!for!intuitive!querying!CIDOC!CRM!based!repositories,!described!in!Tzompanaki!&!Doerr! (2012).!Users!can!formulate!queries!by!selecting!from!six!basic!categories!and!the!relations!between! them! without!the!need! to!be!familiar!with!the!underlying! schema.!The!results!of!the!queries!are! coming!from!the!different!datasets,!and!it!is!possible!to!refine!the!search!with!a!facet!view.! The! coin! demonstrator! has! shown! that! datasets! of! different! origin,! language,! property,! and! of! heterogeneous!information!can!be!successfully!integrated!by!relying!on!the!CIDOC!CRM.!The!relative! homogeneity!of!the!coin!class!of!objects!has!made!the!mapping!and!conversion!work!relatively!easy.! But!validity!of!the!methodological!approach!can!be!assumed!for!any!type!of!archaeological!object.! The&sculptures&demonstrator&& This!demonstrator!has!been!developed!by!researchers!of!the!German!Archaeological!Institute!(Gerth! et! al.! 2016a/b).! The! researchers! produced! and! explored! a! dataset! of! semantic! data! from! five! different!databases!based!on!the!CIDOC!CRM,!including!the!extensions!CRMsci!and!CRMarchaeo!for! describing! scientific! data! acquisition! and! archaeological! excavation! processes.! Furthermore! the! demonstrator!used!the!object-oriented!version!of!Functional!Requirements!for!Bibliographic!Records! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 233!Blazegraph,!https://www.blazegraph.com!! 234!Metaphacts,!http://www.metaphacts.com!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!103!January!2017! ! (FRBRoo)235!for! describing! bibliographical! records! and! the! Basic! Geo! vocabulary236!for! simple! geometry! description.! The! researchers! developed! a! prototypical! implementation! of! the! different! standards! for! archaeological! research! regarding! time,! space,! actors,! literature! and! other! entities! covered!by!domain-specific!vocabulary.!! The!following!datasets!have!been!used!in!the!demonstrator:! o German!Archaeological!Institute:!Arachne237!and!data!from!the!iDAI.field!instance!of!the!Chimtou! project238,! o British!Museum:!!Semantic!Web!Collection!Online239,! o Oxford!Roman!Economy!Project:!Stone!Quarries!Database240,! o American!School!of!Classical!Studies!in!Athens:!Athenian!Agora!Excavation!data241.! The! pilot! application! presents! a! case! of! integration! of! various! datasets! with! different! origins! (museum!catalogue,!object!database,!excavation!database,!research!results).!The!data!resources!are! provided! with! different! services! and! interfaces! and! therefore! required! a! novel! strategy! for! integration,!based!on!CIDOC!CRM.!The!data!of!the!British!Museum!could!be!accessed!directly!via!its! SPARQL!endpoints!and!integrated!by!using!a!SPARQL!federated!query;!the!British!Museum!has!the! data! already! organised! based! on! CIDOC! CRM.! Arachne’s! data! could! be! exported! via! an! OAI-PMH! interface,!which!provides!RDF/XML!using!CIDOC!CRM.!The!other!data!exports!were!transformed!to! XML!and!imported!into!FORTH-ICS’!Mapping!Memory!Manager.!The!3M!editor!was!used!to!describe! the!datasets!with!CIDOC!CRM!and!transform!the!data!into!RDF!format.!! To!enable!a!unified!search!environment!for!all!datasets!it!was!also!necessary!to!harmonize!differing! CIDOC!CRM!mappings!as!well!as!map!terms!to!a!common!reference!vocabulary,!e.g.!archaeological! terminology!to!the!AAT!and!places!to!the!iDAI.gazetteer.!! The! Linked! Data! has! been! stored! in! a! Blazegraph! graph! database! (triple! store)! to! perform! archaeologically!relevant!SPARQL!queries!on!the!data!to!showcase!the!possibilities!of!the!approach.! The!search!interface!has!been!implemented!with!Metaphacts!on!top!of!the!Blazegraph!triple!store! and!allows!accessing!the!data!in!a!wiki!system.! An! object-centric! and! a! sites-based! view! into! the! cloud! of! archaeological! linked! data! have! been! explored.! The! research! questions! in! the! object-centric! view! concerned! comparable! objects! by! applying!the!same!parameters.!For!example!one!object-centric!query!was!about!a!fragmentary!head! of!a!Satyr!that!was!found!in!Chimtou.!The!sites-based!view!concerned!quarries,!for!example!quarries! where!white!marble!was!produced.!Here!search!questions!were!about!all!possible!sculptures!from!a! specific!quarry!(Pentelli),!and!literature!that!describes!objects!which!are!made!out!of!the!marble!of! that!quarry.!The!approach!demonstrated!the!advantages!of!the!extended!CIDOC!CRM!for!research!as! queries!to!answer!archaeological!questions!could!be!run!successfully!over!to!integrated!datasets.!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! 235!FRBRoo!model,!v2.1,!February!2015,!http://www.cidoc-crm.org/frbr_drafts.html!! 236!Basic!Geo!(WGS84!lat/long)!Vocabulary,!https://www.w3.org/2003/01/geo/!! 237!Arachne,!the!central!object!database!of!the!German!Archaeological!Institute!and!the!Archaeological! Institute!of!the!University!of!Cologne,!http://arachne.uni-koeln.de!! 238!Deutsches!Archäologisches!Institut,!Simitthus!/!Chimtou!(Tunesien)!Projekt,! http://www.dainst.org/projekt/-/project-display/33904!! 239!British!Museum!-!Semantic!Web!Collection!Online,!http://collection.britishmuseum.org!! 240!Oxford!Roman!Economy!Project!(Oxford!University):!Stone!Quarries!Database! http://oxrep.classics.ox.ac.uk/databases/stone_quarries_database/!! 241!Agora!Excavations!(American!School!of!Classical!Studies!in!Athens),!http://agora.ascsa.net!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!104!January!2017! ! The&wooden&material&demonstrator& The!wooden!material!demonstrator!is!being!developed!by!University!of!South!Wales!(Hypermedia! Research!Group)!in!collaboration!with!ADS,!DANS!and!SND.!It!aims!to!investigate!the!potential!for! Natural! Language! Processing! information! extraction! techniques! to! achieve! a! degree! of! semantic! interoperability!between!archaeological!datasets!and!the!textual!content!of!grey!literature!reports.! Thus! the! aim! is! to! extract! more! specific! information! from! the! reports!than! is! available! in! the! metadata! alone.! Similar! NLP! methods! will!be! employed! to! those!used! in! the!Coins!demonstrator! described!above.!The!work!builds!on!the!techniques!developed!for!the!UK!STAR!Project!(Tudhope!et! al.!2011b;!Vlachidis!et!al.!2015).!Output!will!be!expressed!as!RDF!using!the!same!CIDOC!CRM!model! as!used!for!the!Coins!Demonstrator!with!mappings!made!to!the!AAT.!! The!case!study!has!a!broad!theme!relating!to!wooden!material!including!shipwrecks,!with!a!focus!on! indications! of! types! of! wooden! material,! samples! taken,! wooden! objects! with! dating! from! dendrochronological! analysis,! etc.! The! work! is! ongoing! and! will! be! reported! in! the!forthcoming! ARIADNE!deliverable!D15.3!(ARIADNE!2017b).!The!intention!is!to!draw!on!both!English!and!Dutch! language!datasets!and!grey!literature!reports,!together!with!Swedish!archaeological!reports.!The!end! result!will!be!a!SPARQL!pilot!demonstrator!of!the!technical!possibilities,!operating!over!a!Linked!Data! expression!of!the!output,!which!will!offer!cross!search!over!both!the!datasets!and!text!reports.!It!is! intended! that! the! demonstrator! will! explore! possibilities! for! a! more! (archaeology)! user-centred! application! interface! (using! the! ‘widget’! techniques! developed! in! the! SENESCHAL! project)! than! a! plain!SPARQL!endpoint.! 7.7 Brief&summary&and&lessons&learned& Brief&summary& The! developmental! ARIADNE! Linked! Data! work! described! in! this! chapter! has! focused! on! the! production!of!(and!support!for)!SKOS!subject!vocabularies,!mappings!between!those!vocabularies! and!the!Art!&!Architecture!Thesaurus,!in!order!to!provide!a!multilingual!capability,!and!the!mappings! of!datasets!to!the!CIDOC-CRM.!Furthermore! three! advanced!case! studies! with! demonstrators!are! presented!that!generate!and!use!Linked!Data!based!on!the!CIDOC!CRM!and!key!subject!vocabulary! hubs:!coins,!wooden!material!and!sculptures.!! The!first!two!case!studies!involve!information!extraction!from!text!reports!in!addition!to!mapping! datasets,! while! the! third! explores! external! linking! beyond! the! immediate! ARIADNE! datasets.! Exploratory!work!on!mining!of!Linked!Data!and!NLP!techniques!are!described!but!both!are!research! areas! with! potential! for! much! further! work.! The! transformation! of! the! metadata! of! the! datasets! registered!in!the!ARIADNE!data!catalogue!to!Linked!Data!is!described!in!the!next!chapter,!as!are!the! details!of!the!ARIADNE!Linked!Data!service.!! The!demonstrators!are!still!being!finalised!at!the!time!of!this!deliverable!but!will!be!available!for! general!use!via!the!ARIADNE!Portal.!For!the!reasons!discussed!in!the!early!chapters,!the!case!studies! are!experimental!investigations!of!the!future!use!cases!that!are!afforded!by!Linked!Data!technology;! they! result! in! (working)! research! demonstrators! rather! than! actual! operational! systems.! They! illustrate!the!kinds!of!possibilities!for!cross!search!and!the!semantic!integration!of!diverse!kinds!of! datasets!and!text!reports!that!Linked!Data!and!the!related!semantic!technologies!make!possible.!! One!obvious!finding!from!the!experience!to!date!is!the!critical!importance!of!the!subject!vocabularies! (e.g.!the!AAT)!combined!with!the!CIDOC!CRM!ontology!entities,!which!act!as!linking!hubs!in!the!web! of!data.!More!work!is!needed!on!the!identification!of!further!linking!hubs!and!consequent!semantic! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!105!January!2017! ! enrichment!of!the!Linked!Data!to!relevant!external!datasets.!One!example!of!a!potential!linking!hub! is!the!Period0!set!of!cultural!periods!which!can!be!used!by!providers!of!various!archaeological!and! other!cultural!heritage!datasets.! Necessary!for!the!widespread!uptake!of!the!Linked!Data!approach!is!the!availability!of!a!variety!of! mapping! and! alignment! software! for! different! contexts,! together! with! evaluative! studies! and! guidelines!as!to!their!use.!Beyond!that,!to!motivate!user!organisations!to!devote!scarce!resources!to! working!with!Linked!Data,!some!exemplar!working!applications!are!needed!that!address!a!real!user! (scientific/research)!need.!Such!applications!should!offer!a!user!interface!that!is!easy!and!attractive! to!work!with,!one!that!does!not!require!programming!skills!or!detailed!knowledge!of!the!underlying! data!schema!or!ontology!structure.!! It!should!not!necessarily!be!assumed!that!the!end-application!directly!operates!over!a!(Linked!Data)! triple!store.!There!are!advantages!in!doing!so!for!data!updates!and!external!connections!and!it!is!an! obvious!route.!However,!periodic!harvesting!of!Linked!Data!is!a!possibility!for!applications!that!have! reasons!to!employ!a!wider!range!of!programming!platforms.!Another!possibility!is!for!Linked!Data! providers!to!consider!exposing!programmatic!web!services!for!application!developers!(in!addition!to! a! SPARQL! endpoint),! assuming! that! an! appropriate! set! of! of! use! cases! for! the! services! can! be! identified.! Lessons&learned& o Mapping!of!datasets!to!established!domain!KOSs!(in!our!case!CIDOC!CRM,!AAT!and!others)!allows! their!integration!within!and!beyond!the!catalogue!of!a!data!portal.!! o State-of-the-art! linking! hubs! will! play! an! increasingly! important! role! in! the! web! of! LOD,! comprehensive!domain!thesauri!as!the!AAT!as!well!as!specialised!vocabularies!like!the!Nomisma! thesaurus.!! o The! mapping! of! datasets! to! such! hubs! requires! domain! knowledge,! easy! to! use! tools,! and! guidance! of! users! who! carry! out! such! work! for! the! first! time.!While! recommender! tools! are! helpful,!fully!automated!mapping!appears!unlikely!to!achive!quality!results!at!the!current!time.! o The!ARIADNE!portal!and!pilot!demonstrators!show!that!this!work!is!worth!the!effort.!But!there!is! still!a!way!to!go!before!advanced!uses!of!LOD! will!become!applicable!and!beneficial!in! online! research!environments;!more!effort!must!be!invested!to!make!this!happen.!! o There!is!much!scope!to!explore!the!utility!of!LOD!in!practice,!taking!account!of!the!objectives!and! requirements!of!different!user!communities.!The!best!ways!to!provide!and!employ!LOD!will!largely! depend!on!their!specific!contexts!(museum!collections,!data!archives!or!research!platforms,!for! instance),! together! with! the! anticipated! use! cases.! In! order! to! motivate! user! organisations! to! work!with! Linked! Data,! exemplar! working! applications! that! address! a! real! user! (scientific/research)!need!would!be!very!helpful.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!112!January!2017! ! 8.4 The&Demonstrators& The! Demonstrators! represent! three! different! subject! areas! of!archaeology,! coins,! sculptures! and! wooden!material.!The!datasets!that!are!being!employed!by!the!Demonstrators!are!described!above.! The!datasets!have!been!harmonized,!where!necessary,!using!the!CIDOC!CRM!(and!recent!extensions),! transformed! into! RDF! graphs!and! ingested! into! the! ARIADNE! LOD! Cloud.! The! Demonstrators! are! described! in! greater! detail! in! the! deliverable! D14.2!Pilot! Deployment! Experiments!and! the! deliverable!D15.3!Semantic!Annotation!and!Linking.! The!Demonstrators!will!become!accessible!to!end-users!through!a!dedicated!Linked!Data!Section!on! the! ARIADNE! Portal.! They! have! been! developed! to! exemplify! the! capability! of! Linked! Data! based! item-level!data!integration!to!support!answering!archaeological!research!questions.!This!capability! builds!on!the!mapping!of!datasets!to!the!CIDOC!CRM!(including!recent!extensions)!and!other!domain! vocabularies!(i.e.!AAT,!Nomisma!and!others).!Here!we!give!a!brief!account!of!some!promising!results! that!have!been!obtained!in!demonstrators.! The!Coins!Demonstrator!can!illustrate!important!points!that!are!present!also!in!other!demonstrators.! The! Coins! Demonstrator! employs! datasets! of! different! providers! (including! results! of! NLP! of! archaeological! grey! literature),! mappings! to! the! CIDOC! CRM! (and! CRMdig! extension),! and! other! domain!vocabularies!(AAT,!Nomisma).!Furthermore!it!presents!a!case!that!shows!the!potential!of! querying,!in!the!ARIADNE!LOD!Cloud,!this!item-level!data!together!with!catalogue-level!data.!! Queries!across!the!datasets!of!the!Coins!Demonstrator!show!useful!results!for!researchers.!Queries! that!are!trivial!to!be!answered!by!each!dataset!separately!become!relevant!for!a!researcher!when! they!are!executed!across!several!datasets,!and!the!results!combined!by!the!researcher.!For!example! searches!such!as!Find!coins!minted!in!the!same!place/area,!Find!coins!minted!by!the!same!authority! (e.g.!Antonianus),!Find!coins!produced!in!the!same!period!(e.g.!the!same!century),!Find!coins!made! from! specific! material!(e.g.! bronze),! etc.!Moreover,! item-level! and! catalogue-level! data!can! be! queried!simultaneously,!e.g.!Find!the!publishers!of!all!collections!that!contain!bronze!antoninianus.! The! Sculptures! Demonstrator!has! the! same! general! characteristic!but! involves! some! different! aspects.! For! example,! the! datasets! include! data! from! excavations!and! instead! of! grey! literature! reports!the!large!Zenon!bibliographic!database!of!the!German!Archaeological!Institute!is!involved.! Consequently!the!Sculptures!Demonstrator!employs!the!CRM!extensions!CRMarchaeo!and!CRMsci! and!Functional!Requirements!for!Bibliographic!Records!(FRBRoo),!along!with!other!vocabularies!(e.g.! the! AAT! and! the! iDAI.gazetteer).!Also! this! demonstrator! shows! advanced! capability! to! support! answering! archaeological! research! questions.! For! example,! queries! over! the! datasets! concerned! quarries! where! white! marble! was! produced,! all! possible! sculptures! from! a! specific! quarry,! and! literature!that!describes!objects!which!are!made!out!of!the!marble!of!that!quarry.! The!wooden!material!Demonstrator!also!shares!the!general!characteristics!with!a!particular!focus!on! the! integration! of! grey! literature! textual! reports! in! different! languages! with! datasets! on! a! dendrochronological! theme.! The! complexity! of! the! underlying! semantic! framework! based! on! the! CIDOC! CRM! and! Getty! AAT! is! shielded!from! the!user!by! the!Web! application! user! interface.! The! Demonstrator!highlights!the!potential!for!archaeological!research!that!can!interrogate!grey!literature! reports!in!conjunction!with!datasets.!Queries!concern!wooden!objects!(e.g.!samples!of!beech!wood! keels),!optionally!from!a!given!date!range,!with!automatic!expansion!over!hierarchies!of!wood!types.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!113!January!2017! ! 8.5 The&Mapping&and&Ontology&Server& The!Mapping!and!Ontology!Server!provides!information!about!the!mappings!and!the!vocabularies! (ontologies,!thesauri)!involved!in!the!ARIADNE!LOD!Cloud.!! The!following!mappings!of!datasets!to!the!CIDOC!CRM!(and!extensions)!are!available:! o Schemas!of!the!Italian!Central!Institute!for!Catalogue!and!Documentation!for!archaeological!finds! (RA)!and!monuments!and!complexes!(MA/CA)!mapped!to!the!CRM,!using,!where!required,!more! specialised!classes!and!properties!of!CRM!extensions!(provided!by!ICCU);! o Database! schema! and! concepts! of! SITAR,! the! Archaeological! Territorial! Informative! System! of! Rome!mapped!to!the!CRM!and!CRMarchaeo!(ICCU!in!cooperation!with!other!institutions);! o dFMRÖ!(coins!database)!mapped!to!CRM,!CRMdig!and!a!specialized!extension!for!coins,!used!in! the!Coins!demonstrator!(ÖAW);! o iDAI.field!database!of!the!Pergamon!project!mapped!to!CRM,!CRMarchaeo!and!CRMsci,!used!in! the!Coins!demonstrator!(DAI);! o iDAI.field!database!of!the!Chimtou!project!including!stone!objects!and!archaeological!contexts,! mapped!as!above!and!used!in!the!Sculpture!demonstrator!(DAI);! o Athenia!Agora!excavation!database!(over!280,000!data!items),!mapped!as!above!and!used!in!the! Sculptures!demonstrator!(DAI);! o Digital! Collaboratory! for! Cultural! Dendrochronology! (DCCD)! dataset,! an! extract! facilitated! by! DANS,!mapped!to!the!CRM!(USW);! o Dendrochronology! Database! of! the! Vernacular! Architecture! Group! (UK),! 2016!(doi:! 10.5284/1039454),!provided!by!ADS,!mapped!to!the!CRM!(USW);! o Cruck! Database! of! the! Vernacular! Architecture! Group! (UK),! 2015! (doi:! 10.5284/1031497),! provided!by!ADS,!mapped!to!the!CRM!(USW);! o Newport!Medieval!Ship.!N.!Nayling!&!T.!Jones,!2014!(doi:!10.5284/1020898),!dataset!provided!by! ADS,!mapped!to!the!CRM!(USW);!! o Mystery!Wreck!Project!(Flower!of!Ugie).!Hampshire!and!Wight!Trust!for!Maritime!Archaeology,! 2012!(doi:!10.5284/1011899),!dataset!provided!by!ADS,!mapped!to!the!CRM!(USW);! o Animal!Bone!Evidence!South!England!(doi:10.5284/1000102),!dataset!provided!by!ADS,!mapped! to!the!CRM!and!extensions!and!used!in!an!Animal!Remains!demonstrator!(DAI);! o Holozängeschichte! der! Tierwelt! Europas! (doi:10.13149/001.mcus7z-2),! dataset! provided! by! IANUS,!mapped!and!used!as!above!(DAI).! The!following!ontologies!are!available!as!references:! o CIDOC!CRM!core.!Version!5.0.4,!December!2011;! o CRMarchaeo.! Model! for! integrating! metadata! about! the! archaeological! excavation! process;! introduces!concepts!of!stratigraphy!and!excavation.!Version!1.4,!April!2016;! o CRMsci.! Model! for! integrating! metadata! about! scientific! observation,! measurements! and! processed!data.!Version!1.2.3,!April!2016;! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!114!January!2017! ! o CRMdig.!Model!of!digitisation!processes,!to!encode!metadata!about!the!steps!and!methods!of! production!(“provenance”)!of!digital!representations!such!as!2D,!3D!or!animated!models.!Version! 3.2.1,!April!2016;! o CRMba.!Model!for!investigating!historic!and!prehistoric!buildings,!the!relations!between!building! components,!functional!spaces,!topological!relations!and!construction!phases!through!time!and! space;!harmonized!with!CRMarchaeo.!Version!1.4,!April!2016;! o CRMgeo.!Spatio-temporal!model!that!integrates!CRM!and!OGC!standards.!Version!1.2,!February! 2015;! o CRMinf.! Model! for! integrating! data! with! scholarly! argumentation! and! inference! making! in! descriptive!and!empirical!sciences;!harmonized!with!CRMsci.!Version!v0.7,!February!2015;! o Functional!Requirements!for!Bibliographic!Records,!FRBRoo!encoded!in!RDFS.!Version!2.4,!June! 2016.! The!following!thesauri!in!SKOS!are!available!as!references:! o AAT!-!Art!&!Architecture!Thesaurus!(Getty);! o PACTOLS!thesaurus!!(Peuples,! Anthroponymes,! Chronologie,! Toponymes,! Œuvres,! Lieux! et! Sujets)! of! the! Fédération! et! ressources! sur! l’Antiquité,! France.! A! large! multi-lingual! thesaurus! which! focuses! on! antiquity! and! archaeology! from! prehistory! to! the! industrial! age;! terms! in! French,! English,! German,! Italian,! Spanish,! Dutch,! and! (some)! Arabic).! Over! 1600! PACTOLS! concepts,!used!by!Inrap!in!their!catalogue!of!archaeological!reports!(DOLIA),!have!been!mapped! to!the!AAT;! o Historic!England!thesauri!(Forum!on!Information!Standards!in!Heritage!–!FISH),!thesauri!in!SKOS! provided!by!HeritageData!(SENESCHAL!project).!ADS,!employs!five!of!the!thesauri!(monuments,! components,!building-material,!maritime-craft,!fish!objects)!of!which!about!850!concepts!have! been!mapped!to!the!AAT;! o PICO!thesaurus!(ICCU):!A!large!thesaurus!of!terms!related!to!culture!and!cultural!heritage!(Italian! and! English)! which! is! being! used! for! the! data! of! CulturaItalia;! a! number! of! terms! concern! archaeology!which!have!been!mapped!to!the!AAT;! o Italian! Archaeological! Finds! Vocabulary!/! Reperti! Archeologici! (RA)! Thesaurus,! a! thesaurus! describing!archaeological!finds!(ICCU);!! o RCE! Archeologisch! Basisregister! -! ABRr+! thesauri! (Rijksdienst! Cultureel! Erfgoed,! Netherlands),! about!450!concepts!of!monument!types!(Archeologische!complextypen)!have!been!mapped!by! DANS!to!the!AAT;!! o Irish!Monument!Types!thesaurus!(National!Monuments!Service),!a!hierarchical!list!of!concepts! expressed!in!SKOS!as!part!of!the!LoCloud!project;! o iDAI.vocab:! group! of! 14! thesauri! of! archaeological! terminology! in! different! languages!and! of! varied!size;!the!German!thesaurus,!mapped!to!the!AAT,!serves!as!the!central!hub!to!and!through! which!the!other!thesauri!are!linked;! o iDAI.Gazetteer:!provides!over!1!million!entries!describing!modern!and!ancient!places!that!are!of! interest!to!the!archaeologists!and!also!acts!as!a!hub!by!linking!other!gazetteers!like!Geonames! and!Pleiades;! o Dendrochronology! multi-lingual! vocabulary!of! the! Digital! Collaboratory! for! Cultural! Dendrochronology,!developed!and!recently!expressed!in!SKOS!by!DANS;!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!115!January!2017! ! o EAGLE!epigraphy!vocabularies!(Material,!Type!of!inscription,!Execution!technique,!Object!type,! Decoration,!Dating!criteria,!State!of!preservation);! o Nomisma!ontology!of!numismatic!concepts!and!entities!(Nomisma.org).! 8.6 Promotion&of&external&use& One! of! the! core! principles! of! Linked! Open! Data! is! linking! of! published! datasets! to! others! which! generates! an! expanding! and! increasingly! rich! web! of! Linked! Data.! Promotion! of! linking! relevant! datasets!to!the!ARIADNE!LOD!by!external!developers!is!planned! to!include! documentation!of!the! data!in!relevant!registries,!targeted!dissemination!of!information!about!the!available!data,!and!direct! discussion!with!a!number!of!interested!developers.!! Data! registration:! Documenting! sets! of! LOD! in! relevant! registries!makes! it! easier! for! application! developers!to!identify,!evaluate!and!link!to!relevant!datasets.!The!Vocabulary!of!Interlinked!Data!Sets! (VoID)!is!most!often!being!used!to!describe!and!register!sets!of!LOD.!In!VoID!a!dataset!is!a!collection! of!data,!published!and!maintained!by!a!single!provider,!available!as!RDF,!and!accessible,!for!example,! through!a!SPARQL!endpoint.!Figure!3!illustrates!a!VoID!description!of!the!ARIADNE!LOD:! @prefix!rdf:!<http://www.w3.org/1999/02/22-rdf-syntax-ns#>!.! @prefix!rdfs:!<http://www.w3.org/2000/01/rdf-schema#>!.! @prefix!foaf:!<http://xmlns.com/foaf/0.1/>!.! @prefix!dcterms:!<http://purl.org/dc/terms/>!.! @prefix!void:!<http://rdfs.org/ns/void#>!.! :ARIADNE-LOD!!a!void:Dataset;! !!!!!dcterms:title!"ARIADNE!registry";! !!!!!dcterms:publisher!"ARIADNE!Project";! !!!!!foaf:homepage!<http://registry.ariadne-infrastructure.eu>;! !!!!!dcterms:description!"A!registry!of!data!for!archaeological!research";! !!!!!dcterms:license!<http://opendatacommons.org/licenses/by/>;! !!!!!void:sparqlEndpoint!<http://ariadne2.isti.cnr.it/sparql>;! !!!!!…! Figure!3:!VoID!description!of!the!ARIADNE!registry! ! The!final!ARIADNE!LOD!will!be!registered!in!the!Data!Hub!(datahub.io),!where!also!some!resources! employed!by!ARIADNE!can!be!found!(e.g.!the!Getty!AAT,!English!Heritage!thesauri,!and!others);!other! registries!and!platforms!(e.g.!Github,!Wikidata)!are!being!considered.!! Targeted! dissemination:!Announcements! and! other! information! about! the! available! LOD! will! be! disseminated!via!relevant!mailing!lists,!newsletters!etc.!of!the!Linked!Data!community!in!the!fields!of! archaeology,!cultural!heritage,!classical!studies,!history!and!other!humanities.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!116!January!2017! ! Direct!consultation!with!developers:!A!number!of!Linked!Data!application!developers!of!institutions! and!projects!will!be!contacted!directly!to!suggest!and!discuss!interlinking!with!their!or!other!available! datasets!in!the!web!of!LOD.! 8.7 Brief&summary&and&lessons&learned& Brief&summary& The!ARIADNE!registry!holds!metadata!of!data!resources!from!the!content!providers.!These!metadata! are! being! collected! and! enriched! with! an! aggregator! (MORe)! and! included! in! the! ARIADNE! data! catalogue.!ARIADNE!makes!the!catalogue!and!other!data!generated! in! demonstrators!available!as! Linked!Open!Data!(LOD);!thereby!the!ARIADNE!LOD!can!become!part!of! a!web!of!Linked!Data! of! archaeological!and!related!other!information!resources.! This!work!within!ARIADNE!involved!the!use!of!a!suitable!RDF!store!and!graph!database!for!the!Linked! Data! generation! and! linking! efforts.! The! project! has! experimented!with! two! such! technologies,! Virtuoso! and! Blazegraph,! to! perform! archaeologically! relevant! SPARQL! queries! on! the! generated! Linked! Data,! and! to! allow! updates! of! datasets! using! the! SPARQL! 1.1! Graph! Store! HTTP! Protocol.! Based! on! this! preliminary! work,! a! scalable! implementation! that! can! efficiently! support! the! publication! and! use!of!the! ARIADNE! LOD!has! been! designed!and!realized!to!offer! three!different! services:!the!Linked!Open!Data!Server,!the!Demonstrators,!and!the!Mapping!and!Ontology!Server.!! The! Linked! Open! Data! Server! provides! access! to! a! large! RDF! dataset,! which! comprises! of! several! graphs!of!archaeological!datasets!and!can!be!queried!via! a!SPARQL!endpoint.!The!Demonstrators! have!been!developed!to!exemplify!the!capability!of!Linked!Data!based!item-level!data!integration!to! support!answering!archaeological!research!questions.!They!represent!three!different!subject!areas!of! archaeology:! coins,! sculptures! and! wooden! material.! For! each! a! number! of! datasets! have! been! integrated!based!on!mappings!to!the!CIDOC!CRM!(and!recent!extensions)!and!use!of!other!domain! vocabularies.!The!Mapping!and!Ontology!Server!provides!information!about!the!mappings!and!the! vocabularies!(ontologies,!thesauri)!involved!in!the!ARIADNE!LOD!Cloud.! The!current!ARIADNE!LOD!Cloud!is!just!the!initial!stage!of!an!information!space!that!is!expected!to! grow!in!terms!of!data,!vocabularies,!services!and!users.!Experiments!to!exploit!the!ARIADNE!LOD! have!just!started,!with!promising!results!as!shown!by!the!Demonstrators.!Planned!future!work!will! aim! to! proceed! with! linking! the! available! Linked! Data! to! relevant! other!datasets.! To! promote! interlinking,!the!ARIADNE!LOD!will!be!announced!via!relevant!mailing!lists,!newsletters!etc.!of!the! Linked!Data!community!in!the!field!of!archaeology!and!cultural!heritage.!A!number!of!Linked!Data! developers! will!also! be! contacted! directly! to! suggest! and! discuss! interlinking! with! their! or! other! available!datasets!in!the!web!of!LOD.! Lessons&learned& While!the!Linked!Open!Data!standards!are!essential!for!integrating!data,!the!technology!supporting! such!integration!is!still!in!its!infancy.!The!ARIADNE!LOD,!comprising!of!LOD!of!the!ARIADNE!catalogue,! three! demonstrators! and! various! vocabularies! sum! up! to! about! 32! million! RDF!triples.! While! any! relational! database! can! easily! handle! millions! of! records,! the! corresponding! amount! of! RDF! in! a! current!triple!store!can!cause!serious!efficiency!problems!as!experienced!in!the!experimentation!with! the!ARIADNE!Linked!Data!Cloud.!It!is!becoming!apparent!that!this!is!the!price!to!be!paid!to!have! interoperability.! More! robust! and! efficient! graph! databases! are! required! if! we! want! to! proceed! towards!Big!Data!as!Linked!Data.!This!is!the!first!lesson!that!we!have!learned!while!implementing!the! ARIADNE!Linked!Data!Cloud.! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!117!January!2017! ! The!second!lesson!comes!from!the!graph!data!model.!This!model!is!intrinsically!binary,!hence!makes! it!difficult!to!express!higher!rank!relations,!and!to!easily!implement!data!connection!patterns.!In!the! latter! case,! the! patterns! may! involve! data! chains! that! span! several! arcs,! and! their! definition! and! implementation!is!not!trivial.!Conversely,!correlations!between!data!items!can!be!epitomized!by!such! paths,!which!need!to!be!detected,!and!this!is!a!computationally!very!intensive!task!if!the!length!of! the!paths!go!beyond!2-3!arcs.!This!fact!has!always!been!known!from!a!theoretical!point!of!view,!but! working!with!real!data!we!could!experience!it!in!practice.! ! ! ! ! ! !& ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!118!January!2017! ! 9 References&and&relevant&other&sources& ! 5!★!Open!Data!(details!Berners-Lee’s!5-star!scheme!of!Linked!Open!Data!with!examples!and!explains! benefits!of!and!some!issues!in!providing!such!data),!http://5stardata.info!! Acheson,!Phoebe!(2014):!Linked!Open!Bibliographies!in!Ancient!Studies.!ISAW!Paper!7.2,! http://dlib.nyu.edu/awdl/isaw/isaw-papers/7/! Agosti!M.,!Conlan!O.,!Ferro!N.!et!al.!(2013):!Interacting!with!Digital!Cultural!Heritage!Collections!via! Annotations:!The!CULTURA!Approach.!DocEng’13,!Florence,!Italy,!September!10–13,!2013,! http://www.digitalmeetsculture.net/wp-content/uploads/2013/12/Interacting-with-DigitalCultural-Heritage-Collections-via-Annotations.pdf!! Agricultural!Information!Management!Standards!(AIMS):!Vocabularies,!Metadata!Sets!and!Tools! (VEST)!registry:!KOS,!http://aims.fao.org/vest-registry/vocabularies! AGROVOC!Linked!Open!Data,!http://aims.fao.org/standards/agrovoc/linked-open-data!! Alexander!K.,!Cyganiak!R.,!Hausenblas!M.!&!Zhao!J.!(2009):!Describing!Linked!Datasets.!On!the!Design! and!Usage!of!voiD,!the!“Vocabulary!of!Interlinked!Datasets”.!In:!Proceedings!of!the!Linked!Data! on!the!Web!(LDOW‘09)!workshop,!Madrid,!Spain,!20!April!2009.!http://ceur-ws.org/Vol538/ldow2009_paper20.pdf!! Allemang!D.!&!Hendler!J.!(2011):!Semantic!Web!for!the!Working!Ontologist.!Effective!Modeling!in! RDFS!and!OWL!Second!Edition.!Morgan!Kaufmann! Almas!B.,!Babeu!A.!&!Krohn!A.!(2014):!Linked!Data!in!the!Perseus!Digital!Library.!ISAW!Paper!7.3,! http://dlib.nyu.edu/awdl/isaw/isaw-papers/7/! Almeida!B.,!Roche!C.!&!Rute!C.!(2016):!Terminology!and!ontology!development!in!the!domain!of! Islamic!archaeology,!pp.!147-156,!in:!Erdman-Thomsen!H.,!Pareja-Lora!A.!&!Nistrup!Madsen!B.! (2016):!Term!Bases!and!Linguistic!Linked!Open!Data.!TKE!2016!-!12th!International!conference! on!Terminology!and!Knowledge!Engineering.!Copenhagen!Business!School,! http://openarchive.cbs.dk/handle/10398/9323! Aloia!N.,!Papatheodorou!C.,!Gavrilis!D.,!Debole!F.!&!Meghini!C.!(2014):!Describing!Research!Data:!A! Case!Study!for!Archaeology,!pp.!768–775,!in:!Meersman!R.!et!al.!(eds.):!On!the!Move!to! Meaningful!Internet!Systems:!OTM!2014!Conferences.!Springer!(LNCS!8841);!preprint,! https://www.academia.edu/19889230/Describing_Research_Data_A_Case_Study_for_Archaeol ogy!! Amsterdam!Museum!in!Europeana!Data!Model!RDF,!http://semanticweb.cs.vu.nl/lod/am! Ancient!World!Mapping!Centre!(AWMC!/!University!of!North!Carolina):!Antiquity!À-la-carte!and! public!map!tiles,!http://awmc.unc.edu/wordpress/alacarte/!! !Anichini!F.!&!Gattiglia!G.!(2012):!MappaOpenData.!From!web!to!society.!Archaeological!open!data! testing,!pp.!54-56,!in:!Opening!the!Past:!Archaeological!Open!Data,!MapPapers!3-II,! http://mappaproject.arch.unipi.it/wp-content/uploads/2011/08/Pre_atti_online3.pdf!! Antike!Fundmünzen!in!Europa!(web-based!coins!database!developed!by!the!Romano-Germanic! Commission!of!the!German!Archaeological!Institute),!http://afe.fundmuenzen.eu!!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!119!January!2017! ! Arbuckle!S.,!Whitcher-Kansa!S.,!Kansa!E.,!Orton!D.!et!al.!(2014):!Data!Sharing!Reveals!Complexity!in! the!Westward!Spread!of!Domestic!Animals!across!Neolithic!Turkey.!In:!PLoS!ONE,!9(6):!e99845,! http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0099845!! Archaeogeomancy.net!(2014):!Colonisation!of!Britain,!30!May!2014,! http://www.archaeogeomancy.net/2014/05/colonisation-of-britain/!!! Archaeology!Data!Service!(2015):!ADS!/!Internet!Archaeology!Annual!Report,!1.8.2014–31.7.2015,! http://archaeologydataservice.ac.uk/attach/annualReports/ADS%20Annual%20Report%202014 -15.pdf!! Archaeology!Data!Service:!Linked!Open!Data,!http://data.archaeologydataservice.ac.uk!! Archaeology!Data!Service:!The!STELLAR!project,! http://archaeologydataservice.ac.uk/research/stellar/! Archaeotools!-!Data!mining,!facetted!classification!and!E-archaeology!(UK,!e-Science!Research!Grant,! 2007-2009),!http://archaeologydataservice.ac.uk/research/archaeotools!! ArcheoInf!-!Informationszentrum!für!die!Archäologie!(Germany,!DFG-funded!project,!2008-),! http://archeoinf.tu-dortmund.de!! Archeologisch!Basisregister!(Rijksdienst!Cultureel!Erfgoed!/!Cultural!Heritage!Agency!of!the! Netherlands),!http://abr.erfgoedthesaurus.nl!! Archer!P.,!Dekkers!M.,!Goedertier!S.,!Harzard!N.!&!Loutas!N.!(2013):!Study!on!business!models!for! Linked!Open!Government!Data!(BM4LOGD).!Study!prepared!for!the!ISA!programme!by!PwC!EU! Services,!23!November!2013,!https://joinup.ec.europa.eu/community/semic/document/studybusiness-models-linked-open-government-data-bm4logd! Archives!Hub,!http://archiveshub.ac.uk!! Archives!Hub:!LOCAH!-!Linked!Archives!and!Linking!Lives!projects!(2010-2012),! http://locah.archiveshub.ac.uk!! ARENA!-!Archaeological!Records!of!Europe!-!Networked!Access!project!(2001-2004,!and!2009-2010!in! the!context!of!DARIAH),!http://ads.ahds.ac.uk/arena/search/!!! ARIADNE!-!Linked!Data!SIG!(2013):!First!Meeting,!EAA!2013!Conference,!Pilsen,!4!September!2013,! http://www.ariadne-infrastructure.eu/Community/Special-Interest-Groups/Linked-Data!!! ARIADNE!-!Linked!Data!SIG!(2014):!Second!Meeting,!CAA!2014!Conference,!Paris,!23!April!2014,! http://www.ariadne-infrastructure.eu/Community/Special-Interest-Groups/Linked-Data!!! ARIADNE!(2013):!D3.2!Report!on!Project!Standards!(November!2013),!http://www.ariadneinfrastructure.eu/Resources/D3.2-Report-on-project-standards!! ARIADNE!(2014a):!D2.1!First!Report!on!Users’!Needs!(April!2014),!http://www.ariadneinfrastructure.eu/Resources/D2.1-First-report-on-users-needs! ARIADNE!(2014b):!Modeling!scientific!data:!workshop!report,!12!September!2014,! http://www.ariadne-infrastructure.eu/News/Modeling-scientific-data! ARIADNE!(2014c):!The!Way!Forward!to!Digital!Archaeology!in!Europe.!November!2014,! http://www.ariadne-infrastructure.eu/Media/Files/Ariadne-Booklet-The-Way-Forward-toDigital-Archaeology-in-Europe! ARIADNE!(2015a):!D2.2!Second!Report!on!Users’!Needs!(February!2015),!http://www.ariadneinfrastructure.eu/content/view/full/1188!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!120!January!2017! ! ARIADNE!(2015b):!D16.1!First!Report!on!Data!Mining!(March!2015),!http://www.ariadneinfrastructure.eu/Resources/D16.1-First-Report-on-Data-Mining!! ARIADNE!(2015c):!D16.2!First!Report!on!Natural!Language!Processing!(May!2015),! http://www.ariadne-infrastructure.eu/Resources/D16.2-First-Report-on-Natural-LanguageProcessing!! ARIADNE!(2015d):!ARIADNE!at!Linked!Pasts:!Checking!in!on!the!state!of!the!art!for!Linked!Open!Data! and!Cultural!Heritage.!ARIADNE!news,!7!August!2015,!http://www.ariadneinfrastructure.eu/News/ARIADNE-at-Linked-Pasts!!! ARIADNE!(2015e):!D2.3!Preliminary!Innovation!Agenda!and!Action!Plan!(November!2015),! http://www.ariadne-infrastructure.eu/Resources/D2.3-Preliminary-Innovation-Agenda-andAction-Plan! ARIADNE!(2016a):!D14.1!Extended!CRM!(April!2016),!http://www.ariadneinfrastructure.eu/Resources/D14.1-Extended-CRM!! ARIADNE!(2016b):!D15.1!Report!on!Thesauri!and!Taxonomies!(August!2016),!http://www.ariadneinfrastructure.eu/Resources!! ARIADNE!(2017a):!D14.2!Pilot!Deployment!Experiments!(January!2017),!will!be!available!at! http://www.ariadne-infrastructure.eu/Resources! ARIADNE!(2017b):!D15.3!Report!on!Semantic!Annotation!and!Linking!(January!2017),!will!be!available! at!http://www.ariadne-infrastructure.eu/Resources! ARIADNE!Catalogue!Data!Model!(ACDM),!http://support.ariadne-infrastructure.eu! ARIADNE!Datasets!Registry,!http://registry.ariadne-infrastructure.eu! ARIADNE:!Ariadne!Reference!Model!(set!of!CIDOC!CRM!extensions,!including!reference!document,! presentation,!RDFS!encoding),!http://www.ariadne-infrastructure.eu/Resources/AriadneReference-Model!! Aroyo!L.,!Hyvönen!E.!&!van!Ossenbruggen!J.!(eds.,!2007):!Cultural!Heritage!on!the!Semantic!Web.! Proceedings!of!the!workshop!co-located!with!the!6th!International!Semantic!Web!Conference,! Busan,!Korea,!http://www.cs.vu.nl/~laroyo/CH-SW/ISWC-wp9-proceedings.pdf! ArSol!-!Archives!du!Sol!(Soil!Archives)!project,!http://arsol.univ-tours.fr!!! Arwe,!John!(2011):!Coping!with!Un-Cool!URIs!in!the!Web!of!Linked!Data.!Presented!at!the!Linked! Enterprise!Data!Patterns!Workshop.!Data-driven!Applications!on!the!Web,!Cambridge,!6! December!2011,!http://www.w3.org/2011/09/LinkedData/ledp2011_submission_5.pdf!! ASIS&T!(2014):!Special!section!Economics!of!Knowledge!Organization!Systems.!ASIS&T!-!Bulletin!of! the!Association!for!Information!Science!and!Technology,!40(4):!13-42,! http://asis.org/Bulletin/Apr-14/Bulletin_AprMay14_Final.pdf!! Aspöck!E.!&!Geser!G.!(2014):!What!is!an!archaeological!research!infrastructure!and!why!do!we!need! it?!-!Aims!and!challenges!of!ARIADNE.!In:!Proceedings!of!the!18th!International!Conference!on! Cultural!Heritage!and!New!Technologies!(CHNT!18),!Vienna,!November!2013,! http://www.chnt.at/wp-content/uploads/Aspoeck_Geser_2014.pdf!! Assaf!A.!&!Senart!A.!(2012):!Data!Quality!Principles!in!the!Semantic!Web.!ICSC'12!Proceedings!of!the! 2012!IEEE!Sixth!International!Conference!on!Semantic!Computing;!preprint:!arXiv:1305.4054! [cs.DL],!http://arxiv.org/ftp/arxiv/papers/1305/1305.4054.pdf!! ! ARIADNE!–!D15.2:!Report!on!the!ARIADNE!Linked!Data!Cloud!Prepared!by!CNR-ISTI,!SRFG!and!USW! ARIADNE!121!January!2017! ! AthenaPlus!(2013a):!First!release!GLAM!sector!reference!terminologies.!Project!deliverable!4.1,! September!2013,!http://www.athenaplus.eu/getFile.php?id=187! AthenaPlus!(2013b):!Review!on!Linked!Open!Data!Sources.!Project!deliverable!4.2,!October!2013,! http://www.athenaplus.eu/getFile.php?id=190! AthenaPlus!(EU,!CIP!Best!Practice!Network,!3/2013-8/2015),!http://www.athenaplus.eu!! Auer!S.,!Bühmann!L.,!Dirschl!C.!et!al.!(2012a):!Managing!the!Life-Cycle!of!Linked!data!with!the!LOD2! Stack.!ISWC!2012!-!11th!International!Semantic!Web!Conference,!Boston,!USA,!11-15.11.2012,! http://iswc2012.semanticweb.org/sites/default/files/76500001.pdf!(also:! http://svn.aksw.org/lod2/Paper/ISWC2012-InUse_LOD2-Stack/public.pdf)!! Auer!S.,!Demter!J.,!Martin!M.!&!Lehmann,!J.!(2012b):!LODStats!-!An!Extensible!Framework!for!Highperformance!Dataset!Analytics.!Proceedings!of!the!EKAW!2012!–!18th!International!Knowledge! Engineering!and!Knowledge!Management!Conference,!Galway!City,!Ireland,!8-12!October!2012,! http://svn.aksw.org/papers/2011/RDFStats/public.pdf!! Bagosi!T.,!Calvanese!D.,!Hardi!J.!et!al.!(2014):!The!Ontop!Framework!for!Ontology!Based!Data!Access! (OBDA),!pp.!67-77,!in:!CSWS!2014!-The!Semantic!Web!and!Web!Science!-!8th!Chinese! Conference,!Wuhan,!China,!8-12!August!2014,!Springer;!pre-print,! http://www.inf.unibz.it/~calvanese/papers/bago-etal-CSWS-2014.pdf!! Barbera!N.,!Meschini!F.,!Morbidoni!C.!&!Tomasi!F.!(2012):!Annotating!digital!libraries!and!electronic! editions!in!a!collaborative!and!semantic!perspective,!pp.!46-57,!in:!Agosti!M.!et!al.!(eds):!Digital! Libraries!and!Archives.!8th!Italian!Research!Conference!(IRCDL!2012),!CCIS!354,!Heidelberg.! Springer,!http://dspace.unitus.it/bitstream/2067/2331/1/paper_annotation_last.pdf!! BARTOC!-!Basel!Register!of!Thesauri,!Ontologies!&!Classifications!(Basel!University!Library,! Switzerland),!http://www.bartoc.org!!! 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