A NOVEL EVALUATION METHODOLOGY FOR DETERMINING I-LEVEL TEST CYCLE-TIME IN MISSILE MAINTENANCE

Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4744 A NOVEL EVALUATION METHODOLOGY FOR DETERMINING I-LEVEL TEST CYCLE-TIME IN MISSILE MAINTENANCE CHENG-WEN LEE1, YUAN-CHAO CHI2, ROMI ILHAM3 1Department of International Business, Chung Yuan Christian University, Taiwan 2Ph.D Program in Business, Chung Yuan Christian University, Taiwan 3Ph.D Program in Business, Chung Yuan Christian University, Taiwan 3Department of Accounting, Universitas Hayam Wuruk Perbanas, Indonesia E-mail: [email protected], [email protected], [email protected] ABSTRACT The periodic testing cycle of missiles is a critical factor influencing operational readiness, reliability, and associated logistics costs, including maintenance, transportation, and testing. Despite the importance of optimizing these cycles, a clear understanding of the optimal testing intervals for different missile types remains underexplored. This study investigates the impact of various I-Level periodic testing cycles for Ktype missiles, utilizing the "Important Factor Weighted Exponential Distribution Function (IFWEDF)" method to estimate and compare reliability across different intervals. A cost-benefit analysis is then conducted to evaluate the implications of extending the testing cycle. The results indicate that a three-year testing cycle optimizes reliability while minimizing costs. This paper offers a novel approach to missile maintenance strategy formulation and contributes to the existing literature by providing evidence-based recommendations for determining optimal testing cycles in missile systems. The findings of this research can inform future strategies for military maintenance planning and contribute to cost-effective operational readiness management. Keywords: I-Level Periodic Testing Cycle, Important Factor Weighted Exponential Distribution Function (IFWEDF) 1. INTRODUCTION When a missile weapon system completes development, passes verification, and enters mass production, it is officially commissioned for service. At this stage, periodic testing of the missiles becomes a necessary step to ensure they can perform their operational readiness missions effectively. These tests are designed to ensure that missiles remain in a launch-ready state. Therefore, strict implementation of maintenance and testing protocols is essential to guarantee their availability. Missile maintenance is primarily divided into three levels: Organizational Level (O-Level), Intermediate Level (I-Level), and Depot Level (DLevel)[1][2][3]. The specific tasks for each maintenance level are detailed in Figure 1. Maintenance at the O-Level is carried out by operational units, with the main goal of ensuring that missiles can execute operational readiness missions within the full missile framework. This level of maintenance typically includes visual inspection of the missile’s exterior, resistance measurement of ignition circuits, or Built-in Tests (BIT)[4][5]. BIT refers to the system's internal automatic detection and fault isolation capabilities, and its testing frequency varies depending on the missile model. If a missile failure is detected during OLevel testing, the entire missile assembly will need to be sent to the I-Level for comprehensive testing to identify the faulty component (e.g., guidance section, warhead section) and perform module replacement or repair. For the missile system studied in this paper, each missile must be sent to the I-Level for testing and maintenance every two years. I-Level maintenance is conducted using Automatic Test Equipment (ATE) to perform comprehensive testing. When a module failure is identified, the faulty module is replaced. If the module cannot be repaired, support from the D-Level is requested, or the faulty section is sent to the D-Level for further repair. Additionally, missiles may be damaged during transport, loading, or operational readiness due to accidental incidents (e.g., dropping, lightning strikes). In such cases, the missiles must also be sent to the D-Level for testing and repair. Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4745 Figure 1: Tasks for Each Missile Maintenance Level From the tasks associated with missile maintenance levels shown above, it is evident that the periodic testing cycles at the I-Level play a significant role in missile maintenance. The length of the testing cycle directly affects missile reliability. According to research, the reliability of missiles changes with their age [6], and the phenomenon of degradation is mainly caused by the test effect [7]. During testing, missiles are subjected to various stresses, effectively accelerating the aging of electronic components. Factors such as false alarms (misidentifying a functioning missile as faulty), testing procedures, and operational errors contribute to an increased missile failure rate. Due to false alarms, missiles are often transported to the I-Level for comprehensive testing, which increases testing time. The longer the testing duration, the greater the stress imposed on internal missile modules. Additionally, the number and sequence of testing procedures significantly affect the stress experienced by the missile. A greater number of test items or improper steps can exacerbate the stress on the missile. Operational errors, often caused by insufficient familiarity with testing steps, lack of expertise, or failure to follow standard operating procedures (SOPs), may also lead to module failures. The length of the I-Level periodic testing cycle also affects logistics and transportation costs between the O-Level and I-Level. A shorter testing cycle increases transportation frequency, resulting in higher transportation and manpower costs. However, an overly extended testing cycle may fail to ensure that missiles remain in optimal working condition. Therefore, O-Level and I-Level testing cycles should not be overly frequent to avoid adversely impacting missile reliability. Yet, without testing, it is impossible to confirm whether missiles are in proper working condition. Thus, it is crucial to study the appropriateness of I-Level periodic testing cycles. From the above discussion, it is clear that ILevel periodic testing negatively impacts missile reliability, and shorter testing cycles increase logistics costs associated with missile transportation. This study analyzes and evaluates I-Level periodic testing cycles using relevant statistical methods, aiming to explore the feasibility of extending the ILevel testing cycle for missiles. The goal is to reduce logistics costs while enhancing missile reliability. 2. LITERATURE REVIEW 2.1. U.S. Navy Harpoon Missiles The Harpoon Missile can be categorized into three configurations: air-launched, shiplaunched, and submarine-launched [8]. The maintenance hierarchy of the Harpoon Missile is divided into three levels: Organizational Level (Olevel, used by operational units), Intermediate Level (I-level, performed at maintenance facilities), and Depot Level (D-level, carried out by the manufacturer). The maintenance process is shown in Figure 2. At the O-level maintenance tier, visual inspections of the missile's exterior and Built-In Test (BIT) are conducted. If the test results indicate a failure, the faulty missile is promptly replaced with a backup missile and sent to the I-level maintenance facility for further subsystem testing using the Missile Subsystem Test Set (MSTS) [7]. Figure.2: Harpoon Missile Maintenance Concept Diagram Additionally, all missiles must undergo regular MSTS testing. If the BIT test indicates a missile failure, the missile will be subjected to MSTS testing. If the test results identify a failed component, it will be sent to the D-level for further repairs. The I-level maintenance facilities also assist the D-level with missile upgrade operations [11]. The D-level, managed by the original manufacturer, is responsible for repairing or replacing subassemblies. New or repaired subassemblies are reinstalled into the subsystem and returned to the I- Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4746 level maintenance facility for subsystem integration and BIT testing. Once the missile passes the test, it is returned to operational units for combat readiness. The maintenance cycle for each level is as follows: O-Level: Air-launched missiles undergo a complete BIT test during loading onto aircraft, while ship-launched and submarine-launched missiles are subjected to BIT tests every six months. ILevel and D-Level: If an failure cannot be resolved at the I-level, it is escalated to the D-level for repair. 2.2. U.S. Air Force Tactical Missiles The periodic testing cycle for U.S. Air Force missiles at the I-level is detailed in Table 1. Prior to 1981, the U.S. Air Force mandated periodic testing every two years. As storage durations increased and failure rates did not rise, the testing interval was extended to three years between 1981 and 1986. Based on subsequent test results, the interval was further extended to five years by the end of 1986 [11]. Table 1: U.S. Air Force Missile I-Level Periodic Testing Cycle Timeline Level I periodic test cycles Reasons for the extended test cycle Before 1981 2 years - 1981-1986 3 years Extended Storage Duration with No Increase in Failure Rate After 1986 5 years Testing Interval Extended Based on Additional Test Results 2.3. Missile Failure Modes Missiles are not solely composed of electronic equipment; they also include mechanical components (e.g., actuators, disjointed mechanisms), electronic components (e.g., navigation systems, flight controls, seekers), oneshot items (e.g., rockets), and non-mechanical lifelimited components (e.g., propellant, batteries). The interfaces between these components are highly complex, and each component has unique characteristics. Notably, components such as engines, igniters, gas generators, safety arming devices, and detonators are highly sensitive to storage conditions, such as temperature and humidity [9][10]. Therefore, missiles must undergo regular inspections and testing after long-term storage and readiness missions to ensure their quality and performance [11]. The U.S. military conducted live-fire tests on a missile produced 27 years ago to confirm that the aging weapon remains reliable and operational [12]. This indicates that although missile reliability gradually degrades over time, it can still fulfill combat readiness missions. 2.4. Impact of Storage, Testing, and Transportation on Failure Rates 2.4.1. Transportation effect According to Theunissen [13], research on Harpoon missiles reveals that vibration and shock have a far greater impact on the failure rate than temperature and humidity. 2.4.2. Testing effects Malcolm explained: “Time itself is not a stress factor. Instead, the testing process imposes various stresses on the missile. Factors such as false alarms, testing procedures, or operational errors significantly increase the failure rate [7]”. Figure 3 illustrates the impact of testing effects on failure rates. Storage conditions are not the primary cause of failures; in fact, testing effects have a more pronounced influence on failure rates [11]. Figure.2: Illustration Of The Impact Of Testing Effects On Failure Rates Figure 4 presents a quantitative description of the testing effect. When the storage failure rate (λs) is significantly lower than the test failure rate (λt), it indicates that the test failure rate (λt) is extremely high, suggesting that the testing process is highly inefficient. If λs is lower than λt, it indicates that the test failure rate is slightly higher, meaning that testing is not performed frequently. Conversely, when λs is significantly higher than λt, it indicates that the test failure rate (λt) is very low, reflecting a highly efficient testing process [7]. Note: N = the number of tests conducted after storing the missile for t years Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4747 F = the number of test failures (the slope determines λs, while the y-intercept determines λt) If λs << λt, it indicates inefficient testing. If λs < λt, it suggests infrequent testing. Figure.4: The Criterion For Determining The Efficiency Of Storage Testing 2.5. Storage Conditions From the perspective of missile deployment, the stages of storage and dormancy occupy most of the missile's service life [14]. "Storage" refers to the condition where equipment is not connected to a system and is packaged and preserved in mild environmental conditions or after an extended period of storage. In contrast, "Inert storage" refers to a state where components or equipment remain connected to the system in normal operational status but experience stress or environmental conditions below normal or routine operational levels [11][15]. For missile deployment, assembled missiles on launchers and powered for readiness are considered in Inert storage, while missiles stored in depots are categorized as being in storage. This distinction highlights the significant differences in environmental stresses experienced during these two phases. From a reliability perspective, the failure rates during storage and dormancy phases also differ. Malcolm [7] conducted studies on various tactical missiles, performing flight tests after longterm storage. The results showed that the reliability of the guidance and control section did not degrade with increased storage time. For electronic equipment, the failure rate during storage was zero. Any observed degradation in missile reliability during testing was actually due to testing effects. 3. COMPREHENSIVE ANALYSIS The primary cause of missile reliability degradation is not storage or inert storage conditions. On the contrary, environmental factors during testing and transportation processes, particularly vibration and shock, have the greatest impact on missile reliability. 3.1. General Exponential Distribution Theory Mathematical models for reliability typically include binomial distribution, exponential distribution, Weibull distribution, and normal distribution. Among these, the exponential distribution model is commonly used for reliability estimation of electronic components due to its mathematical simplicity [16][17]. The reliability mathematical model for general components can be expressed as shown in Equation (1) ( ) t i R t e    (1) where ( ) i R t is the reliability of the i-th component at usage time t,  is the failure rate of the i-th component, and t is the usage time. If the reliability ( ) i R t of each component i follows an exponential distribution with a constant failure rate i  , the system reliability is expressed as shown in Equation (2). ( ) t s R t e   =1 N i i t e    (2) 3.2. Important Factor Weighted Exponential Distribution Function This study adopts the "Important Factor Weighted Exponential Distribution Function" to estimate reliability under different periodic testing cycles. This method is an improvement based on the exponential distribution model. Through the literature review mentioned earlier, we identified the key environmental factors affecting reliability, including transportation, testing and storage. As a result, the calculation of missile reliability takes into account the influence of these three factors, with each factor weighted according to its average failure rate. The final reliability of the missile is then determined. The formula for calculating missile reliability is expressed as follows: R =( )m e (3) where m=ΣKini =total number of failures. The greater the value of m, the lower the reliability, indicating harsher environmental conditions that significantly reduce reliability. Ki represents the average failure proportion of the missile in various environments, while ni denotes the number of occurrences the missile experiences in each environment [18]. Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4748 The Ki values are derived from empirical data obtained through actual environmental tests referenced from the literature. The ni values are calculated based on the missile's life cycle and the number of occurrences it undergoes in each environment. The following provides an explanation of the reliability calculation method for missiles: Assume that a K-type missile is delivered to the troops for active service, where the primary storage facilities are O-level and I-level maintenance depots. Most of the time, the missile performs combat readiness missions at aboard ships. An analysis indicates that during its service life, the missile system is exposed to various environmental factors, including transportation, testing and storage. Table 2 summarizes the impact of these three environmental factors on reliability. For example, assume that the missile is transported from the manufacturer to the I-level maintenance depot, with a one-way distance of 400 kilometers, making the total round-trip distance 800 kilometers. After the I-level maintenance depot completes the acceptance testing, the missile is transported to various ships. The average distance between the deployment ships and the I-level maintenance depot is 400 kilometers, with a roundtrip distance of 800 kilometers. Due to the higher mobility of ships, precise calculations are difficult, so the distance to deployment port is used as an estimation standard. Table 2 Overview of the Impact of Transportation, Testing, and Storage on Missile Reliability During Service Item Environment Starting Point Endpoint Km/Time K value n value 1 Transportation Manufacturer I - Level Maintenance Depot Round Trip = 800 = 1600×0.5 0.025 One transportation per D-level maintenance cycle (Note1) 2 I - Level Maintenance Depot Deployment Site Round Trip = 800 = 1600×0.5 0.025 Depends on the maintenance cycle (Note1) 3 Testing I - Level Maintenance Depot Conducting Full Missile Testing Approximatel y Average= 2 hr 0.02 Depends on the maintenance cycle (Note1) 4 Deployment Ship Conducting Missile BIT Testing Approximatel y Average= 0.2 hr 0.002 One test every six months (Note1) 5 Storage Warehouse, Ship NA 0.05 Note2 From the conclusions of the aforementioned literature review, it is evident that the vibration and shock effects caused by transportation and testing [6][7] have the most direct and significant impact on failure rates. Based on the existing literature, it can be concluded that every 1,000 miles (approximately 1,600 kilometers) of transportation results in a reliability decrease of about 5% (i.e., Ki= 0.05) [19]. Therefore, the roundtrip distance from the manufacturer to the I-level maintenance depot, as well as the round-trip distance from the I-level depot to the deployment site, is 800 kilometers, each corresponding to a Ki value of 0.025. The I-level maintenance depot conducts full missile testing according to the periodic testing cycle, with each test lasting approximately 2 hours. Based on the testing effect, each full missile test reduces the missile's reliability by approximately 2% (i.e., Kᵢ = 0.02) [18]. Additionally, the O-level performs a missile BIT test every six months, with each test lasting approximately 0.2 hours. Based on the proportional relationship between the testing time and the average 2-hour full missile test at the I-level maintenance depot, the Kᵢ for O-level testing is 0.002. Malcolm [6] mentioned that the failure rate of electronic equipment during storage is zero. However, the K-type missile, which is the subject of this study, is mostly deployed on ships, and the impact of ship vibrations on reliability cannot be ignored. Based on actual deployment experience, the failure rate of the K-type missile is approximately 15% (i.e., 0.12). After deducting the reliability reductions caused by transportation effects (5%, Ki=0.05) and testing effects (2%, Ki=0.02), the estimated storage effect on ships is approximately 8% (Ki=0.08). 3.3. Comparison of Reliability Estimation Results for Different Periodic Testing Based on Table 2 and Equation (3) mentioned earlier, the reliability estimation results for I-level periodic testing cycles of 2 years, 3 years, 5 years, 7 years, and 9 years were calculated and Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4749 compared. Finally, a comprehensive benefit analysis and evaluation were conducted, and the optimal Ilevel periodic testing cycle was recommended. 4. ANALYSIS RESULTS Based on the research design and the findings from the literature review, the reliability estimation values (R) for I-level periodic testing cycles of 2, 3, 5, 7, and 9 years were calculated. The results are explained as follows: 4.1. Two-Year I-Level Periodic Testing Cycle The impact of transportation, testing, and storage on reliability for a 2-year I-level periodic testing cycle is assessed and summarized in Table 3. The calculation results of the reliability estimation value (R) are detailed as follows. m=0.025+0.125+0.1+0.04+0.05≒0.34 R=exp (-m)= exp (ΣniKi)=exp (-0.34)≒0.71 Table 3: Assessment of the Impact of Transportation, Testing, and Storage on Reliability for a 2-Year I-Level Periodic Testing Cycle Ite m Environment Starting Point Endpoint Km/Time K value n value Ki ni 1 Transportation Manufacture r I - Level Maintenan ce Depot Round Trip = 800 = 1600×0.5 0.025 1 (Performed once every 10 years) (Note) 0.025 2 I - Level Maintenance Depot Deployme nt Site Round Trip = 800 = 1600×0.5 0.025 5 (Performed 5 times every 10 years) (Note) 0.125 3 Testing I - Level Maintenance Depot Conducting Full Missile Testing Approximatel y Average= 2 hr 0.02 5 (Performed 5 times every 10 years) (Note) 0.1 4 Deployment Site or Ship Conducting Missile BIT Testing Approximatel y Average= 0.2 hr 0.002 20 (Performed 20 times every 10 years) (Note) 0.04 5 Storage Warehouse, Ship NA 0.05 1(Served on a ship for 2 years) 0.05 Note: Assuming the D-level maintenance cycle is 10 years 4.2. Three-Year I-Level Periodic Testing Cycle The impact of transportation, testing, and storage on reliability for a 3-year I-level periodic testing cycle is assessed and summarized in Table 3. The calculation results of the reliability estimation value (R) are detailed as follows. m=0.025+0.075+0.06+0.04+0.075=0.2 R=exp (-m)= exp (ΣniKi)=exp (-0.2)≒0.82 Table 4: Assessment of the Impact of Transportation, Testing, and Storage on Reliability for a 3-Year I-Level Periodic Testing Cycle Ite m Environment Starting Point Endpoint Km/Time K value n value Ki ni 1 Transportation Manufacture r I - Level Maintenance Depot Round Trip = 800 = 1600×0.5 0.025 1 (Performed once every 10 years) (Note1) 0.025 2 I - Level Maintenance Depot Deployment Site Round Trip = 800 = 1600×0.5 0.025 3 (Performed 3 times every 10 years) (Note1) 0.075 3 Testing I - Level Maintenance Depot Conducting Full Missile Testing Approximatel y Average= 2 hr 0.02 3 (Performed 3 times every 10 years) (Note1) 0.06 Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4750 4 Deployment Site or Ship Conducting Missile BIT Testing Approximatel y Average= 0.2 hr 0.002 20 (Performed 20 times every 10 years) (Note1) 0.04 5 Storage Warehouse, Ship NA 0.05 1.5(Note2) 0.075 Note: 1.Assuming the D-level maintenance cycle is 10 years, 2.The transportation vibration stress during three years of continuous service on the ship is 1.5 times that of two years of service. 4.3. Five-Year I-Level Periodic Testing Cycle The impact of transportation, testing, and storage on reliability for a five-year I-level periodic testing cycle is assessed and summarized in Table 3. The calculation results of the reliability estimation value (R) are detailed as follows. m=0.025+0.05+0.04+0.04+0.125≒0.28 R=exp (-m)= exp (ΣniKi)=exp (-0.28)≒0.76 Table 5: Assessment of the Impact of Transportation, Testing, and Storage on Reliability for a Five-Year I-Level Periodic Testing Cycle Ite m Environment Starting Point Endpoint Km/Time K value n value Ki ni 1 Transportation Manufacture r I - Level Maintenance Depot Round Trip = 800 = 1600×0.5 0.025 1 (Performed once every 10 years) (Note1) 0.025 2 I - Level Maintenance Depot Deployment Site Round Trip = 800 = 1600×0.5 0.025 2 (Performed 2 times every 10 years) (Note1) 0.05 3 Testing I - Level Maintenance Depot Conducting Full Missile Testing Approximatel y Average= 2 hr 0.02 2 (Performed 2 times every 10 years) (Note1) 0.04 4 Deployment Site or Ship Conducting Missile BIT Testing Approximatel y Average= 0.2 hr 0.002 20 (Performed 20 times every 10 years) (Note1) 0.04 5 Storage Warehouse, Ship NA 0.05 2.5(Note2) 0.125 Note: 1.Assuming the D-level maintenance cycle is 10 years, 2.The transportation vibration stress during three years of continuous service on the ship is 2.5 times that of two years of service. 4.4. Seven-Year I-Level Periodic Testing Cycle The impact of transportation, testing, and storage on reliability for a seven-year I-level periodic testing cycle is assessed and summarized in Table 3. The calculation results of the reliability estimation value (R) are detailed as follows. m=0.025+0.025+0.02+0.04+0.175≒0.285 R=exp (-m)= exp (ΣniKi)=exp (-0.285)≒0.75 Table 6: Assessment of the Impact of Transportation, Testing, and Storage on Reliability for a Seven-Year I-Level Periodic Testing Cycle Item Environment Starting Point Endpoint Km/Time K value n value Ki ni 1 Transportation Manufacture r I - Level Maintenance Depot Round Trip = 800 = 1600×0.5 0.025 1 (Performed once every 10 years) (Note1) 0.025 2 I - Level Maintenance Depot Deployment Site Round Trip = 800 = 1600×0.5 0.025 1 (Performed 1 times every 10 0.025 Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4751 years) (Note1) 3 Testing I - Level Maintenance Depot Conducting Full Missile Testing Approximatel y Average= 2 hr 0.02 1 (Performed 1 times every 10 years) (Note1) 0.02 4 Deployment Site or Ship Conducting Missile BIT Testing Approximatel y Average= 0.2 hr 0.002 20 (Performed 20 times every 10 years) (Note1) 0.04 5 Storage Warehouse, Ship NA 0.05 3.5 (Note2) 0.175 Note: 1.Assuming the D-level maintenance cycle is 10 years, 2.The transportation vibration stress during three years of continuous service on the ship is 3.5 times that of two years of service. 4.5. Nine-Year I-Level Periodic Testing Cycle The impact of transportation, testing, and storage on reliability for a nine-year I-level periodic testing cycle is assessed and summarized in Table 3. The calculation results of the reliability estimation value (R) are detailed as follows. m=0.025+0.025+0.02+0.04+0.225≒0.335 R=exp (-m)= exp (ΣniKi)=exp (-0.335)≒0.72 Table 7: Assessment of the Impact of Transportation, Testing, and Storage on Reliability for a Nine-Year I-Level Periodic Testing Cycle Ite m Environment Starting Point Endpoint Km/Time K value n value Ki ni 1 Transportation Manufacture r I - Level Maintenance Depot Round Trip = 800 = 1600×0.5 0.025 1 (Performed once every 10 years) (Note1) 0.025 2 I - Level Maintenance Depot Deployment Site Round Trip = 800 = 1600×0.5 0.025 1 (Performed 1 times every 10 years) (Note1) 0.025 3 Testing I - Level Maintenance Depot Conducting Full Missile Testing Approximatel y Average= 2 hr 0.02 1 (Performed 1 times every 10 years) (Note1) 0.02 4 Deployment Site or Ship Conducting Missile BIT Testing Approximatel y Average= 0.2 hr 0.002 20 (Performed 20 times every 10 years) (Note1) 0.04 5 Storage Warehouse, Ship NA 0.05 4.5( Note2) 0.225 Note: 1.Assuming the D-level maintenance cycle is 10 years, 2.The transportation vibration stress during three years of continuous service on the ship is 4.5 times that of two years of service 4.6. Comprehensive Forecast Results and Analysis 4.6.1. Comprehensive forecast results Based on the forecast results mentioned above, the estimated R-values for the fixed measurement cycles in years 2, 3, 5, 7, and 9 are summarized in Figure 5. The figure shows that the estimated R-values for these cycles are 0.71, 0.82, 0.76, 0.75, and 0.72, respectively. Journal of Theoretical and Applied Information Technology 15th June 2025. Vol.103. No.11 © Little Lion Scientific ISSN: 1992-8645 www.jatit.org E-ISSN: 1817-3195 4752 Figure 5: Estimated R-Values Of Missiles For Different Fixed Measurement Cycles 4.6.2. Comprehensive analysis Based on the estimated R-values for the fixed measurement cycles of 2, 3, 5, 7, and 9 years, it is evident that the 3-year cycle provides the highest efficiency. According to the literature review, the U.S. Air Force has set the I-level fixed measurement cycle for missiles at 5 years. Analysis indicates that most of their missiles are stored in bunkers and are only mounted on aircraft during training exercises. Therefore, a 5-year cycle can still ensure missile reliability. However, since K-type missiles are deployed on ships, they must withstand prolonged ship vibrations and higher temperatures in their operational regions, which can accelerate aging and affect reliability. As a result, fixed measurement cycles should not be standardized across different environments. 4.7. Analysis of Actual Missile Failure Conditions in Service If the periodic I-level test cycle is extended to three years, the current stability and quality of the missiles must be considered. According to the failure statistics of K-type missiles during deployment from P1 to P15, as shown in Table 8, the number of failures was relatively low in the early deployment stages due to the smaller quantity of missiles. However, both Segment A and Segment B experienced high failure rates in certain modules. After improvements and the installation of upgraded modules, the failure rate gradually decreased. Table 8 presents the failure data of K-type missiles, indicating that Segment A reached its failure peak during P6–P10, while Segment B peaked during P6– P9. To enhance missile reliability, it is essential to further refine, modify, and replace the A and B segments. Table 8: Summary Of K-Type Missile Failure Counts From P1 To P15 Year P 1 P 2 P 3 P 4 P 5 P 6 P 7 P 8 P 9 P10 P11 P12 P13 P14 P15 Segment A 33 10 15 23 19 41 46 36 42 49 24 27 26 27 31 Segment B 0 0 3 7 7 49 44 18 25 9 2 8 18 12 0 Total Failure Count 33 10 18 30 26 90 90 54 46 58 26 35 44 39 31 The failure data underwent statistical analysis [19][20] results indicate that the high failure rates of Segments A and B during the P6–P10 period significantly affected the reliability of K-type missiles. Therefore, based on the stable quality condition of K-type missiles after upgrading Segments A and B to enhanced modules in P10, the I-level periodic test cycle can be extended to three years. 4.8. Correlation Analysis The Pearson correlation analysis [16][17] results, as shown in Table 9, indicate a significant correlation between K-type missile failures and failures in Segments A and B. The regression equation [16][17] is y = -9.1 + 1.71x, with p-value = 0.000, R-Square = 69.2%, and Standardized Residual = 2.34R. The residual analysis is shown in Figure 6. Table 9: Correlation Analysis of K-Type Missile Failures with Segments A and B Failures Item Segment A Failures Segment B Failures Failure Count Pearson Correlation Coefficient 0.832 0.910 p-value 0.000 0.000 Correlation Significance Significance