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Safety Research :

 

0.8
2023CiteScore
 
22-й процентиль
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Safety, Risk, Reliability and Quality:

 

0.8
2023CiteScore
 
19-й процентиль
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Statistic, Probability and Uncertainty :

 

0.8
2023CiteScore
 
13-й процентиль
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SCImago Journal & Country Rank

 

 

 

 

 

 

STRUCTURAL STRENGTH AND STABILITY ASSESSMENT, RISKS AND POTENTIAL HAZARDS IN THE ARCTIC ENVIRONMENT

31-40

 

 

Alena Rotaru  

 

 

 

The paper deals with the assessment of the strength and stability of structures in Arctic soil conditions. The main attention is paid to the unique properties of such soils, which affect the reliability of structures. These include extremely low temperatures, permafrost, high humidity and the presence of permafrost. It is noted that the existing methods for assessing strength and stability require further development and adaptation. The specifics of Arctic soils should be taken into account when choosing research methods and approaches. The operation of structures in the Arctic is associated with risks of deformation and destruction due to loads associated with soil features. Problems may also occur due to changes in temperature and humidity. To reduce risks and improve the reliability of structures, it is proposed to develop and implement comprehensive security measures. They should take into account the specifics of Arctic soils at all stages-from design to operation of infrastructure facilities. This may include the use of special materials, the adaptation of design solutions, and the development of new methods for monitoring the state of structure. The results of the study can be useful in the design and operation of facilities in the Arctic, as well as in the development of regulatory documents and standards for construction in difficult ground conditions. This will ensure the safety and efficiency of structures in extreme climatic conditions.  

 

Cite: Alena Rotaru   STRUCTURAL STRENGTH AND STABILITY ASSESSMENT, RISKS AND POTENTIAL HAZARDS IN THE ARCTIC ENVIRONMENT. Reliability: Theory & Applications. 2025, June 2(84):  31-40, DOI: https://doi.org/10.24412/1932-2321-2025-284-31-40


 

 

 

ASSESSING TRANSFORMATION RATIO OF VOLTAGE TRANSFORMER UNDER NON-SINUSOIDAL SUPPLY VOLTAGE CONDITIONS 

41-51

 

 

Nurali Yusifbayli, Huseyngulu Guliyev, Naib Hajiyev and Nijat Huseynov  

 

 

 

Voltage transformers are rarely subjected to periodic inspection and testing while in operation, which is the reason for the difference between actual transformation ratios and their rated values. The frequency characteristics of voltage transformers are checked neither. Therefore, there can be large errors in the case of non-sinusoidal supply voltage. Existing studies on the study of voltage transformer faults reflect the results of the study of the equivalent circuit based on traditional lumped-parameter circuits. However, it should be noted that for high-frequency circuits and at the same time from the point of view of taking into account the structure of the windings, increasing the accuracy of the research results is an urgent issue. The case of non-sinusoidal supply voltage is of great scientific interest in this regard. Therefore, considering the voltage transformer as a distributed-parameter circuit, its fault under non-sinusoidal supply voltage was investigated and studied. This work explores errors of voltage transformers in the presence of non-sinusoidal voltage. To this end, a mathematical model of the transformation ratio is built considering the equivalent circuit of transformer as a distributed-parameter circuit.  

 

Cite: Nurali Yusifbayli, Huseyngulu Guliyev, Naib Hajiyev and Nijat Huseynov   ASSESSING TRANSFORMATION RATIO OF VOLTAGE TRANSFORMER UNDER NON-SINUSOIDAL SUPPLY VOLTAGE CONDITIONS . Reliability: Theory & Applications. 2025, June 2(84):  41-51, DOI: https://doi.org/10.24412/1932-2321-2025-284-41-51


 

 

 

ENHANCING SENSITIVITY OF MTTF AND NETWORK RELIABILITY STABILITY OF K-OUT-OF-N ACYCLIC TRANSMISSION NETWORK 

52-66

 

 

Hemalatha.G, Vijayalakshmi.G  

 

 

 

Networks are used in many areas of engineering, including computers and communication, transportation and electric transmission. Component importance measures are applicable to improve the system design. The reliability characteristics of k-out-of-n acyclic transmission network have been evaluated using universal generating function (UGF). This paper explores and analyses Mean Time To Failure (MTTF), Birnbaum importance measurement, critical component importance, component risk growth factor, average risk growth factor and MTTF sensitivity for acyclic transmission network. Finally, The stability illustrates the impact of component failure on the reliability of the network system. The network reliability stability for acyclic transmission network is computed. In this work, we have evaluated reliability characteristics and of the acyclic transmission network using UGF method. The network reliability stability for k-out-of-n acyclic transmission network is computed. Furthermore, numerical illustrations are provided. 

 

 

Cite: Hemalatha.G, Vijayalakshmi.G   ENHANCING SENSITIVITY OF MTTF AND NETWORK RELIABILITY STABILITY OF K-OUT-OF-N ACYCLIC TRANSMISSION NETWORK . Reliability: Theory & Applications. 2025, June 2(84):  52-66, DOI: https://doi.org/10.24412/1932-2321-2025-284-52-66


 

 

 

TWO PARAMETRIC GENERALIZED FUZZY ENTROPY MEASURE WITH SOURCE CODING 

67-77

 

 

Tabasum Fatima, M. A. K. Baig  

 

 

 

In this manuscript, we introduce a new generalized fuzzy information measure for a fuzzy set. We establish its validity as a fuzzy entropy measure. Also, we define a new generalized fuzzy average code-word length for a fuzzy set, and explore its relationship with the fuzzy information measure. We prove coding theorems for discrete noiseless channels. The measures outlined in this communication are not only novel, but also encompass certain well-established measures from the existing literature on fuzzy information theory. We also show the proposed measure through a dataset and and observe its monotonicity through tabular and graphical forms.  

 

Cite: Tabasum Fatima, M. A. K. Baig   TWO PARAMETRIC GENERALIZED FUZZY ENTROPY MEASURE WITH SOURCE CODING . Reliability: Theory & Applications. 2025, June 2(84):  67-77, DOI: https://doi.org/10.24412/1932-2321-2025-284-67-77


 

 

 

SHREEKANT DISTRIBUTION WITH PROPERTIES AND APPLICATIONS TO MODEL STRESS AND STRENGTH DATA FROM ENGINEERING

78-95

 

 

Rama Shanker  

 

 

 

Modeling and analyzing real lifetime data that are stochastic in nature with the existing lifetime distributions is really a challenging task for researchers. During the last decade several one parameter lifetime distributions have been proposed in statistics but almost each of them has been found having some problems regarding their goodness of fit on certain datasets. This might have been due to their distributional properties or due to stochastic nature of datasets. In this paper, a new lifetime distribution named Shreekant distribution has been proposed which has been found to give improved fits to lifetime datasets than those by other existing ones such as exponential, Lindley, Shanker, Akash, Sujatha and Uma distributions. This has been shown by presenting its fittings to two datasets relating to stress and strength data from engineering. Its various structural and other properties and estimation of parameters by different methods of estimation have also been studied.  

 

Cite: Rama Shanker   SHREEKANT DISTRIBUTION WITH PROPERTIES AND APPLICATIONS TO MODEL STRESS AND STRENGTH DATA FROM ENGINEERING. Reliability: Theory & Applications. 2025, June 2(84):  78-95, DOI: https://doi.org/10.24412/1932-2321-2025-284-78-95


 

 

 

ON THE FAILURE RATE FUNCTION OF A SYSTEM UNDER THE δ-SHOCK MODEL

96-100

 

 

Reza Farhadian, Habib Jafari, Hamed Lorvand  

 

 

 

An interesting type of shock model in reliability theory is the delta-shock model, which is defined based on the length of time between successive shocks. Whenever this length is less than or equal to a prefixed threshold called delta, the system will fail. In this paper, the failure rate function of a system subjected to random shocks under the delta-shock model is discussed. To be more precise, a simple approximate formula for the failure rate function is established. Numerical studies are performed under the assumption that the arrival of shocks follows a Poisson process. Based on the numerical results, the accuracy of the approximation is evaluated, and it is also shown that reducing the mean of inter-arrival times between successive shocks leads to an increase in the failure rate of the system. Conclusions are presented at the end.  

 

Cite: Reza Farhadian, Habib Jafari, Hamed Lorvand   ON THE FAILURE RATE FUNCTION OF A SYSTEM UNDER THE δ-SHOCK MODEL. Reliability: Theory & Applications. 2025, June 2(84):  96-100, DOI: https://doi.org/10.24412/1932-2321-2025-284-96-100


 

 

 

COMPARATIVE ANALYSIS OF BAYESIAN ESTIMATION TECHNIQUES FOR GAMMA DISTRIBUTIONS

101-111

 

 

Vijay Kumar Lingutla, Naganani Nadiminti, R. K. Davala  

 

 

 

This paper explores the estimation of the common scale parameter for two Gamma populations using three Bayesian methods: Approximate Bayesian Computation (ABC), Hamiltonian Monte Carlo (HMC), and Metropolis-Hastings (MH). Unlike traditional methods like Maximum Likelihood Estimation (MLE), which can be sensitive to model misspecification, these Bayesian methods are more flexible in handling parameter uncertainty and complex data. ABC bypasses explicit likelihood calculations, HMC improves sampling efficiency through gradient information, and MH offers simplicity and adaptability. A simulation study compares these methods based on bias, mean squared error (MSE), and computational efficiency. Additionally, we apply these methods to real glucose level data from male and female individuals with diabetes, highlighting their strengths and limitations. The results offer practical recommendations for real-world applications involving Gamma distributions, contributing to the advancement of Bayesian estimation techniques in complex parameter estimation problems.  

 

Cite: Vijay Kumar Lingutla, Naganani Nadiminti, R. K. Davala   COMPARATIVE ANALYSIS OF BAYESIAN ESTIMATION TECHNIQUES FOR GAMMA DISTRIBUTIONS. Reliability: Theory & Applications. 2025, June 2(84):  101-111, DOI: https://doi.org/10.24412/1932-2321-2025-284-101-111


 

 

 

STOCHASTIC ANALYSIS THROUGH MATLAB OF TWO-UNIT PARALLEL SYSTEM

112-119

 

 

Sonia, Shakuntla Singla  

 

 

 

This paper presents a reliability modelling of a two parallel unit of manufacturing Industry. Original conservation figures of the manufacturing industry have been applied for this determination. Four kinds of failure were observed: developmental, electronic, motorized and infrastructural failures. Both units of manufacturing plant work in parallel and independently. Various reliability parameters of the plant such as availability, busy period for repair, expected number of repairs and profitability for each type of failure are examined. Graphical Technique of Regenerative Point, process of Markov and Genetic Algorithm are applied for analysis. Profit analysis for the plant is examined with respect to returns of the plant and repair rate along with a graphical representation.  

 

Cite: Sonia, Shakuntla Singla   STOCHASTIC ANALYSIS THROUGH MATLAB OF TWO-UNIT PARALLEL SYSTEM. Reliability: Theory & Applications. 2025, June 2(84):  112-119, DOI: https://doi.org/10.24412/1932-2321-2025-284-112-119


 

 

 

PERFORMANCE ANALYSIS OF SOFTWARE SYSTEM SUBJECT TO PREVENTIVE MAINTENANCE AND SOFTWARE UP-GRADATION FACILITY

120-127

 

 

Kavita Thukral, Shiv Kumar Sharma  

 

 

 

Every industrialist as well as scientist try to satisfy the customers requirement by providing reliable software systems and a software system is reliable and profitable if it is easily manageable. This study analyzes the criteria under which software performs correctly with software upgrade and preventive maintenance facility. It is observed that researcher threw light on negligible, major, and load faults cause software to fail, after which load recovery, major, and negligible upgrades are carried out, but there are no discussion on preventive maintenance concept. Sometimes, to enhance the software reliability and performance, preventive maintenance is utilized and it is better to upgrade the software before completely failure. The webull distributions are followed by all of these failures and upgrade rates. The malfunctioning program can always be fixed by a skilled technician. The software performance is analyzed by applying the regenerative point technique and the semi markov process. Software reliability metrics including mean time to software system failure, software availability, and software profit values are calculated using tables.  

 

Cite: Kavita Thukral, Shiv Kumar Sharma   PERFORMANCE ANALYSIS OF SOFTWARE SYSTEM SUBJECT TO PREVENTIVE MAINTENANCE AND SOFTWARE UP-GRADATION FACILITY. Reliability: Theory & Applications. 2025, June 2(84):  120-127, DOI: https://doi.org/10.24412/1932-2321-2025-284-120-127


 

 

 

PERFORMANCE MEASURES AND PARAMETRIC ESTIMATION OF A PARALLEL-SERIES SYSTEM MODEL WITH WEIBULL FAILURE AND REPPAIR TIME DISTRIBUTIONS

128-140

 

 

Shallu Sharma, Pawan Kumar, Poonam Sharma  

 

 

 

The present paper aims at the study of three non-identical unit parallel-series system model with Weibull failure and repair time distributions. The main focus is on the analysis of reliability characteristics and also estimation of parameters in Classical and Bayesian paradigms. The units in the system are named as A, B and C. In order that system works successfully, unit A and anyone of the units B or C should work. Upon failure a unit will immediately be taken up to repair facility for necessary remedial actions. A single repair facility is available to deal with any kind of failure/fault detected with any unit. First come first served service discipline is followed. The failure and repair time distributions for all the units are taken Weibull with varying parameters. Regenerative point technique is used to study various measure of effectiveness. MLE and Bayes estimates of various failure and repair parameters involved in the study have been obtained. A simulation study has also been undertaken to exhibit the behaviour of obtained characteristics in Classical and Bayesian setup and a comparison is made thereupon. Various conclusions have been drawn from the tables and graphs plotted for numerous performance measures for varying values of repair and failure parameters. Having obtained all the reliability characteristics, the profit incurred by the system has been obtained and studied graphically too.  

 

Cite: Shallu Sharma, Pawan Kumar, Poonam Sharma   PERFORMANCE MEASURES AND PARAMETRIC ESTIMATION OF A PARALLEL-SERIES SYSTEM MODEL WITH WEIBULL FAILURE AND REPPAIR TIME DISTRIBUTIONS. Reliability: Theory & Applications. 2025, June 2(84):  128-140, DOI: https://doi.org/10.24412/1932-2321-2025-284-128-140


 

 

 

EXPONENTIAL TYPE ESTIMATORS OF POPULATION MEAN-A REVIEW

141-155

 

 

Sajad Hussain, Vilayat Ali Bhat  

 

 

 

Survey sampling is a crucial statistical approach for making inferences about population characteristics based on the analysis of a representative sample. This method offers a practical solution for saving time and resources while ensuring reliable outcomes. Auxiliary information plays a pivotal role in enhancing the accuracy of estimators used in finite population sampling. Traditional estimators, such as ratio, product, and regression types, have proven effective in improving the precision of population parameter estimation. The introduction of exponential-type transcendental functions marked a significant advancement in this field, further increasing the efficiency of ratio and product estimators. This study provides an in-depth review of the literature on exponential-type ratio and product estimators, emphasizing their relevance in survey sampling. It examines theoretical progress and practical implementations, showcasing their potential to reduce bias and improve estimation accuracy by leveraging complex relationships between study variables and auxiliary information. The insights from this review contribute to advancing research in finite population sampling and offer valuable directions for future studies in the field.  

 

Cite: Sajad Hussain, Vilayat Ali Bhat   EXPONENTIAL TYPE ESTIMATORS OF POPULATION MEAN-A REVIEW. Reliability: Theory & Applications. 2025, June 2(84):  141-155, DOI: https://doi.org/10.24412/1932-2321-2025-284-141-155


 

 

 

A COMPARATIVE ANALYSIS OF GAMMA AND WEIBULL DISTRIBUTIONS IN TAMIL CINEMA DATA

156-162

 

 

A. Vanathu Suresh, R Subramani, S Vijayan  

 

 

 

This paper aims to systematically investigate the utility of the Gamma and Weibull distributions, focusing on their application to lifetime datasets and clarifying their mathematical and statistical properties. By analyzing lifetime data across various disciplines, the research emphasizes the effectiveness and flexibility of these distributions in capturing the complexities inherent in such data. It underscores the importance of parameters such as standard error, log-likelihood, Akaike Information Criterion (AIC), Bayesian Information Criterion (BIC), and Hannan–Quinn Information Criterion (HQIC) in value estimation. The findings suggest that both distributions provide valuable insights into the underlying data, with practical implications for reliability engineering and failure analysis. Moreover, the study demonstrates that the Weibull distribution offers a better fit to the given data than the Gamma distribution due to its adaptability, which yields superior results. A key contribution of this study is the proposal of a model based on estimating the Conditional Weibull distribution for feature parameters, which accurately predicts a finite mixture of two-parameter Weibull distributions initially verified on datasets.  

 

Cite: A. Vanathu Suresh, R Subramani, S Vijayan   A COMPARATIVE ANALYSIS OF GAMMA AND WEIBULL DISTRIBUTIONS IN TAMIL CINEMA DATA. Reliability: Theory & Applications. 2025, June 2(84):  156-162, DOI: https://doi.org/10.24412/1932-2321-2025-284-156-162


 

 

 

LEAST SQUARES, MAXIMUM LIKELIHOOD, AND ANDERSON-DARLING TYPES ESTIMATORS FOR ENTROPY TRANSFORMED EXPONENTIAL DISTRIBUTION

163-174

 

 

Ikwuoche John DAVID, Stephen MATHEW, Isah Charles SAIDU  

 

 

 

Aim: This research aim is to investigate the performance stability and determine the best estimator among Least Squares (LS), Maximum Likelihood (ML), and Anderson Darling (AD) type (right tail AD, left tail AD, second order right tail AD, and second order left tail AD), estimators for estimating the parameter of the Entropy Transformed Exponential distribution. Methods: A Monte Carlo simulation was conducted to evaluate the finite sample performance stability and efficiency at sample sizes of 20, 100, 250, 700, 1000, 1500, 2500, and 3000. The evaluation measures used for assessment are the Absolute Bias (AB) and Root Mean Square Error (RMSE) as performance metrics. Real life data analysis was performed using a field intensity data measured in microvolts recorded at 5-second intervals. The data is a positive right skewed data and highly peaked. Results: The simulation results demonstrated that the LS method consistently outperformed the ML and AD type estimators. This is based on the lowest values of AB and RMSE obtained across all the eight sample sizes. Additionally, the findings were validated through real world data, where the LS estimator exhibited the lowest standard error and the narrowest confidence interval length. Based on the results, the LS is ranked 1st, right tail AD ranked 2nd, second order right tail AD ranked 3rd, MLE ranked 4th, left tail AD ranked 5th, and second order left tail AD ranked 6th. However, results from t-test in determining the significance of the parameter estimate from each estimator, shows that MLE and second order left tail AD estimates are not significant at 5%. The graphical representation of the field intensity data by each estimators fit clearly depict the LS estimator best describe the data distribution. Conclusion: Based on these findings, the study concludes that the LS estimator is the most effective method for estimating the parameter of the Entropy Transformed Exponential distribution followed by the right tail AD, second order right tail AD, MLE, left tail AD, and second order left tail AD being the least effective estimator.  

 

Cite: Ikwuoche John DAVID, Stephen MATHEW, Isah Charles SAIDU   LEAST SQUARES, MAXIMUM LIKELIHOOD, AND ANDERSON-DARLING TYPES ESTIMATORS FOR ENTROPY TRANSFORMED EXPONENTIAL DISTRIBUTION. Reliability: Theory & Applications. 2025, June 2(84):  163-174, DOI: https://doi.org/10.24412/1932-2321-2025-284-163-174


 

 

 

SOME ADDITIONAL PROPERTIES OF KUMARASWAMY LOG-LOGISTIC DISTRIBUTION BASED ON ORDER RANDOM VARIATES 

175-187

 

 

Bavita Singh, Nazia Wahid, Mahfooz Alam, Aafaq A. Rather  

 

 

 

The Exponentialed Kumaraswamy-Dagum distribution represents a significant advancement in the family of probability distributions. This family encompasses several well-established sub-models, including a variant of the Kumaraswamy-Fisk or Kumaraswamy log-logistic distribution, referred to as the Exponentialed Kumaraswamy-Dagum family distribution. In this paper, we characterize the Kumaraswamy log-logistic (KSLL) distribution by employing the moment features of generalized order statistics. Explicit expressions and recurrence relations are derived for both the single and product moments of generalized order statistics associated with the KSLL distribution. These formulations specifically address record values and moments of order statistics. Additionally, the distribution is further analyzed through conditional moments, and a recurrence relation for single moments of generalized order statistics is established. This rigorous investigation seeks to deepen the understanding of the KSLL distribution and its statistical properties as obtained by generalized order statistics.  

 

Cite: Bavita Singh, Nazia Wahid, Mahfooz Alam, Aafaq A. Rather   SOME ADDITIONAL PROPERTIES OF KUMARASWAMY LOG-LOGISTIC DISTRIBUTION BASED ON ORDER RANDOM VARIATES . Reliability: Theory & Applications. 2025, June 2(84):  175-187, DOI: https://doi.org/10.24412/1932-2321-2025-284-175-187.


 

 

 

COMPARATIVE ANALYSIS OF THE RELIABILITY OF VACUUM AND OIL CIRCUIT BREAKERS

188-193

 

 

Ilham RAHIMLI, Aliashraf BAKHTIYAROV  

 

 

 

In modern power systems, switching equipment plays a crucial role in ensuring the safe and reliable connection and disconnection of electrical circuits. A failure of a circuit breaker can lead to serious consequences, including prolonged power outages and damage to expensive equipment. This paper presents a comparative analysis of the reliability of vacuum and oil circuit breakers, considering operational, technical, and economic factors. It examines the main causes of failures, methods of reliability assessment, and provides a comprehensive evaluation of the effectiveness of each type of breaker under various conditions. The novelty of the proposed solution lies in the in-depth analysis of operational characteristics and a multifaceted evaluation of the impact of external factors on equipment reliability. Modern diagnostic and monitoring methods, including thermography, ultrasonic diagnostics, and the integration of IoT systems for real-time monitoring, are used. These approaches improve the processes of equipment selection and operation, ultimately contributing to the overall reliability of power systems. The paper aims to support informed decision-making in equipment selection to enhance the overall reliability of power systems.  

 

Cite: Ilham RAHIMLI, Aliashraf BAKHTIYAROV   COMPARATIVE ANALYSIS OF THE RELIABILITY OF VACUUM AND OIL CIRCUIT BREAKERS. Reliability: Theory & Applications. 2025, June 2(84):  188-193, DOI: https://doi.org/10.24412/1932-2321-2025-284-188-193.


 

 

 

RELIABILITY ANALYSIS OF THE SHAFT SUBJECTED TO FLUCTUATING LOADS UNDER TORSION AND BENDING MOMENTS WHEN SHEAR STRESS FOLLOWS EXPONENTIAL DISTRIBUTION 

194-200

 

 

Md. Yakoob Pasha, M. Tirumala Devi, T. Sumathi Uma Maheswari  

 

 

 

The reliability of shafts subjected to fluctuating loads is essential for ensuring the safe and efficient operation of rotating machinery in various engineering applications, including automotive, aerospace, and industrial systems. Accurate reliability assessments are crucial to preventing failures and extending the lifespan of mechanical components. This study examines the reliability analysis of shafts subjected to combined torsional and bending moments, which create complex stress states that significantly affect shaft performance and failure behaviour. A statistical model is considered since the shear stress generated is random in nature. Analytical expressions for reliability are derived by changing the parameters twisting moment, bending moment, and shaft diameter.  

 

Cite: Md. Yakoob Pasha, M. Tirumala Devi, T. Sumathi Uma Maheswari   RELIABILITY ANALYSIS OF THE SHAFT SUBJECTED TO FLUCTUATING LOADS UNDER TORSION AND BENDING MOMENTS WHEN SHEAR STRESS FOLLOWS EXPONENTIAL DISTRIBUTION . Reliability: Theory & Applications. 2025, June 2(84):  194-200, DOI: https://doi.org/10.24412/1932-2321-2025-284-194-200.


 

 

 

ANALYSIS OF TWO VACATION POLICIES UNDER RETRIAL ATTEMPTS, MARKOVIAN ENCOURAGED ARRIVAL QUEUING MODEL

201-209

 

 

E. IsmailKhan, V. Narmadha, N. Yathavan  

 

 

 

This paper presents a comprehensive analysis of a single-server Markovian queueing system incorporating two distinct vacation policies under a framework of encouraged arrivals and retrial attempts. The novelty of the model lies in its simultaneous treatment of several realistic operational dynamics: server vacations with acceleratory growth, customer impatience, server breakdown and repair, and encouraged arrivals, where potential customers are motivated to join the system depending on its state. To reflect real-world retrial scenarios, customers who do not receive immediate service reattempt after some time, modeled using a retrial queue mechanism. Two key vacation policies are compared: one governed by a first-come, first-served (FCFS) discipline and the other utilizing bulk service. The paper derives steady-state probabilities and evaluates system performance measures, such as mean queue length, server utilization, and the expected number of retrials.  

 

Cite: E. IsmailKhan, V. Narmadha, N. Yathavan   ANALYSIS OF TWO VACATION POLICIES UNDER RETRIAL ATTEMPTS, MARKOVIAN ENCOURAGED ARRIVAL QUEUING MODEL. Reliability: Theory & Applications. 2025, June 2(84):  201-209, DOI: https://doi.org/10.24412/1932-2321-2025-284-201-209.


 

 

 

CONSTRUCTING A SEPARATE RESERVE IN A CHAIN OF LOW-RELIABILITY ELEMENTS 

210-213

 

 

Gurami Tsitsiashvili, Yury Kharchenko  

 

 

 

In this paper, we construct upper and lower estimates of the minimum separate reserve of low-reliability chain elements of length m, at which the probability of operability of the entire chain becomes close to unity. The appeal to a separate reserve is caused by the properties of this reserve, established by Barlow and Proschan. It is shown that the upper and lower estimates of the minimum separate reserve are quite close. If the probability of operability of an individual element of the chain is 1/ln m, then the minimum reserve volume is of the order ln2 m.  

 

Cite: Gurami Tsitsiashvili, Yury Kharchenko   CONSTRUCTING A SEPARATE RESERVE IN A CHAIN OF LOW-RELIABILITY ELEMENTS . Reliability: Theory & Applications. 2025, June 2(84):  210-213, DOI: https://doi.org/10.24412/1932-2321-2025-284-210-213.


 

 

 

EVALUATING THE IMPACT OF PARAMETER SENSITIVITY IN META-HEURISTICS ON RELIABILITY PERFORMANCE 

214-226

 

 

Shakuntla Singla, Manisha Rani, Shilpa Rani, Umar Muhammad Modibbo  

 

 

 

The optimizing reliability of a system is a crucial target for any industry to have good values and outcomes with the balanced cost of maintenance. The assessment of costs and reliability in intricate systems, such as Distributed Redundancy Architecture (DRA), is essential for optimal system design. Achieving this involves addressing various constraints to enhance the overall system's reliability. Researchers have explored system dependability and cost optimization challenges, emphasizing the evolution of metaheuristic approaches. Enhancing system resilience and optimizing costs are central objectives of this study, aiming to improve the reliability and cost-efficiency of DRA systems. The study's framework builds upon existing metaheuristic methods, including Moth Flame Optimization (MFO), Whale Optimization Algorithm (WOA), Dragonfly Algorithm (DA), Gazelle Optimization Algorithm (GOA), and Coati Optimization Algorithm (COA). The findings reveal that COA demonstrates superior performance compared to other methods. By employing the Coati Optimization Algorithm, this study effectively addresses cost and reliability-optimization challenges, providing highly efficient solutions. Key metrics such as reliability and cost were compared across the five metaheuristic approaches, showcasing COA's advantages. Notably, the Coati Optimization Algorithm delivers faster resolutions and outperforms its counterparts in reducing costs while enhancing system reliability. The results underscore COA's ability to optimize intricate system parameters more effectively than methods like MFO, WOA, GOA, and DA. This research highlights the value of using COA for improving reliability and minimizing expenses in complex systems. It offers a novel approach to addressing these challenges, establishing COA as a powerful tool for optimizing distributed system architectures. By analyzing comparative solutions, the study found that COA consistently achieved better outcomes, affirming its success in reliability and cost optimization. In conclusion, this research emphasizes the importance of advanced metaheuristic techniques, particularly the Coati Optimization Algorithm, in enhancing the performance of Distributed Redundancy Architectures. By presenting a numerical example, the comparison has been made and the outcomes are shown graphically and in the tabular form to have a clear understanding. The findings contribute significantly to the field by providing a robust method for achieving cost-efficient and reliable system designs.  

 

Cite: Shakuntla Singla, Manisha Rani, Shilpa Rani, Umar Muhammad Modibbo   EVALUATING THE IMPACT OF PARAMETER SENSITIVITY IN META-HEURISTICS ON RELIABILITY PERFORMANCE . Reliability: Theory & Applications. 2025, June 2(84):  214-226, DOI: https://doi.org/10.24412/1932-2321-2025-284-214-226.


 

 

 

ESTIMATING THE FRECHET DISTRIBUTION'S SCALE PARAMETER USING BAYESIAN METHODS FOR SYMMETRIC AND ASYMMETRIC LOSS FUNCTIONS  

227-233

 

 

S. C. Premila, S. Jayabharathi, D. Kanagajothi, D. Pachiyappan  

 

 

 

Comparing several estimators to estimate the scale parameter of the Frechet distribution based on complete data when the shape parameter is known is the focus of this research. Using the power function distribution as a prior distribution and the maximum likelihood estimator (MLE), we apply the Bayes estimators under the squared error loss function (SELF), linear exponential loss function (LLF), asymmetric precautionary loss function (APLF), and composite LINEX loss function (CLLF). A Monte Carlo simulation study served as the basis for the comparison. The performance of these estimators in relation to the mean square error (MSE) was compared through the simulation study.  

 

Cite: S. C. Premila, S. Jayabharathi, D. Kanagajothi, D. Pachiyappan   ESTIMATING THE FRECHET DISTRIBUTION'S SCALE PARAMETER USING BAYESIAN METHODS FOR SYMMETRIC AND ASYMMETRIC LOSS FUNCTIONS  . Reliability: Theory & Applications. 2025, June 2(84):  227-233, DOI: https://doi.org/10.24412/1932-2321-2025-284-227-233.


 

 

 

MODELING AND ANALYSIS OF THE WEIGHTED POWER CHRIS JERRY DISTRIBUTION FOR RELIABILITY ENGINEERING 

234-241

 

 

R. Sembiyan, Iyappan. M, D. Suresh, Kalaivanan. S, R. Saranraj  

 

 

 

This paper introduces a new class of probability distribution, termed the Weighted Power Chris Jerry (WPCJ) distribution. This distribution is developed by applying a weighting technique to the baseline Power Chris Jerry distribution, resulting in a more flexible and robust statistical model. The mathematical and statistical properties of the WPCJ distribution, including its moments, reliability measures, and order statistics, are derived and analyzed in detail. The parameters of the proposed distribution are estimated using the Maximum Likelihood Estimation (MLE) method, ensuring effective application in real-world scenarios. To demonstrate the practical utility of the WPCJ distribution, it is applied to a real-life dataset. This application highlights the distribution's ability to model lifetime data effectively, showcasing its superiority over existing models. The weighted distribution approach offers significant advancements in distribution theory, providing enhanced flexibility for modeling complex data structures across various domains, including reliability engineering, biomedicine, and ecological studies. The introduction of weighted distributions is grounded in the foundational work of Fisher and Rao, which demonstrated their importance in situations where observations are influenced by ascertainment methods or weight functions. By extending these principles, the WPCJ distribution offers a novel tool for addressing conceptual challenges in data representation and model development. This study further contributes to the literature by illustrating the adaptability and effectiveness of weighted distributions in tackling diverse analytical problems.  

 

Cite: R. Sembiyan, Iyappan. M, D. Suresh, Kalaivanan. S, R. Saranraj   MODELING AND ANALYSIS OF THE WEIGHTED POWER CHRIS JERRY DISTRIBUTION FOR RELIABILITY ENGINEERING . Reliability: Theory & Applications. 2025, June 2(84):  234-241, DOI: https://doi.org/10.24412/1932-2321-2025-284-234-241.


 

 

 

BAYES ESTIMATES FOR THE PARAMETERS OF POISSON TYPE ONE PARAMETER RAYLEIGH CLASS SRGM USING GAMMA AND INVERTED GAMMA PRIORS

242-249

 

 

Rajesh Singh, Kailash R. Kale and Pritee Singh

 

 

 

Research on the reliability of both software and hardware commonly utilizes the Rayleigh distribution as a model. During software testing, the failure occurrence behavior can be used to evaluate the software's reliability. In this paper, the Poisson pattern of failure occurrence is assumed to study the parameters of the Rayleigh Class software reliability growth model. It has been studied how the Rayleigh Class Model's scale parameter and the quantity of software's intrinsic failures behave. Additionally, using the Gamma and Inverted Gamma Priors, respectively, Bayes estimates for the number of intrinsic failures and the scale parameter are suggested. The comparative analysis of the proposed Bayes estimators and accompanying MLEs is done using the relative efficiency that are acquired via the use of Monte Carlo Simulation.

 

Cite: Rajesh Singh, Kailash R. Kale and Pritee Singh BAYES ESTIMATES FOR THE PARAMETERS OF POISSON TYPE ONE PARAMETER RAYLEIGH CLASS SRGM USING GAMMA AND INVERTED GAMMA PRIORS. Reliability: Theory & Applications. 2025, June 2(84):  242-249, DOI: https://doi.org/10.24412/1932-2321-2025-284-242-249.


 

 

 

COX'S REGRESSION MODEL FOR RELIABILITY ANALYSIS AND FAILURE TIME PREDICTION IN ENGINEERING SYSTEMS 

250-258

 

 

Iyappan. M, Balaji. M, G. Sathya Priyanka, Jesmon Raj. N, P B Deepa  

 

 

 

Accelerated Failure Time Models (AFTMs) are utilized to examine survival patterns, particularly in the context of diseases such as diabetes, where traditional models like Cox proportional hazards may not apply. In this study, we apply AFTMs to identify significant prognostic factors affecting survival in male diabetic patients, using parametric distributions such as Exponential, Weibull, Log-normal, and Log-logistic. The primary objective of this study is to gain deeper insights into how key covariates influence survival times and enhance risk stratification, ultimately leading to better treatment outcomes. We evaluated the fit of several AFTMs by comparing Log-Likelihood, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC) values. Among the models tested, the Weibull AFTM emerged as the best fit, demonstrating superior Log-Likelihood and lower AIC and BIC values compared to other distributions. The study identified several significant predictors of survival in male diabetic patients, including age, family history of diabetes, duration of diabetes, early use of insulin (within one year of diagnosis), retinopathy, use of diuretics, proteinuria, hypertension, and fasting plasma glucose levels. All of these covariates were found to significantly influence survival outcomes (P<0.05), with older age and longer diabetes duration correlating with poorer survival rates. These findings underscore the importance of using AFTMs to model survival patterns in diabetic patients and the potential for targeted interventions based on identified risk factors. While the small sample size limits the generalizability of the results, this study provides valuable insights into the survival characteristics of male diabetic patients and highlights the need for further research with larger datasets. Future studies should consider a wider range of covariates and explore the application of AFTMs in broader diabetic populations to refine survival prediction models and optimize patient care. Additionally, integrating machine learning techniques with AFTMs could enhance predictive accuracy and provide a more comprehensive understanding of survival trends in diabetic patients.  

 

Cite: Iyappan. M, Balaji. M, G. Sathya Priyanka, Jesmon Raj. N, P B Deepa   COX'S REGRESSION MODEL FOR RELIABILITY ANALYSIS AND FAILURE TIME PREDICTION IN ENGINEERING SYSTEMS . Reliability: Theory & Applications. 2025, June 2(84):  250-258, DOI: https://doi.org/10.24412/1932-2321-2025-284-250-258.


 

 

 

BIPOLAR NEUTROSOPHIC MINIMUM SPANNING TREE NETWORK USING UPPER TRIANGULAR WEIGHT/COST ALGORITHM 

259-264

 

 

Shayathri Linganathan, Purusotham Singamsetty  

 

 

 

A minimum spanning tree (MST) is a spanning tree in which the total weights of all of its edges are the lowest of all conceivable spanning trees for the network. MST is crucial in discipline of the operation research. Similarly, for the neutrosophic minimum spanning tree problem (NMST) the weights are unpredictable and inconsistent. The next form of NMST is considered the bipolar neutrosophic minimum spanning tree problem. Each edge of the standard NMST is assigned a bipolar weight based on the bipolar neutrosophic number (consisting of positive and negative membership degrees). This paper introduces the upper triangular weight algorithm for a given network and the optimal results are executed in MATLAB.  

 

Cite: Shayathri Linganathan, Purusotham Singamsetty   BIPOLAR NEUTROSOPHIC MINIMUM SPANNING TREE NETWORK USING UPPER TRIANGULAR WEIGHT/COST ALGORITHM . Reliability: Theory & Applications. 2025, June 2(84):  259-264, DOI: https://doi.org/10.24412/1932-2321-2025-284-259-264.


 

 

 

DESIGNING AN ECONOMIC REPETITIVE GROUP SAMPLING PLAN FOR LIFE TESTS BASED ON PERCENTILES OF EXPONENTIATED RAYLEIGH DISTRIBUTION

265-270

 

 

P. Umanaheswari, S. Suganya, K. Pradeepa Veerakumari  

 

 

 

In this study, a unique Repetitive Group Sampling Plan (RGSP) for life tests is presented, emphasizing the use of percentiles obtained from the Exponentialed Rayleigh Distribution. To enhance the accuracy, effectiveness, and general reliability of life testing techniques, the suggested sample plan provides a strong foundation for assessing the longevity and reliability of goods in a variety of industries. By offering a strong framework for evaluating the robustness and lifespan of products in diverse industries, the suggested sample plan seeks to improve the efficiency and reliability of life testing methods. Through the incorporation of statistical techniques grounded in the Exponentiated Rayleigh Distribution, this research advances the fields of reliability assessment and quality control in industrial processes. Table values are calculated by using Python programming. The implementation of these statistical techniques not only enhances the accuracy of life testing but also enables businesses to make more informed decisions regarding product development and quality assurance. As industries increasingly rely on data-driven approaches, this research provides a valuable resource for optimizing performance and minimizing costs.  

 

Cite: P. Umanaheswari, S. Suganya, K. Pradeepa Veerakumari   DESIGNING AN ECONOMIC REPETITIVE GROUP SAMPLING PLAN FOR LIFE TESTS BASED ON PERCENTILES OF EXPONENTIATED RAYLEIGH DISTRIBUTION. Reliability: Theory & Applications. 2025, June 2(84):  265-270, DOI: https://doi.org/10.24412/1932-2321-2025-284-265-270.


 

 

 

COMMON FIXED POINT THEOREMS IN COMPLEX VALUED B-METRIC SPACES AND USING WEAK COMPATIBLE MAPPINGS 

271-281

 

 

Shivani Chourasiya, Harshit Khare, Kavita Shrivastava  

 

 

 

Complex-valued metric spaces, where the distance between points is represented as a complex number, serve as a generalization of traditional metric spaces and present a variety of intriguing applications, particularly in advanced mathematics and theoretical physics, such as in quantum mechanics, quantum computing, functional analysis, operator theory, complex dynamics, fractal geometry, complex networks, and signal processing, as well as theoretical physics, relativity, geometry, topology, mathematical finance, and economics. Despite the increasing interest in complex-valued metric spaces, the current literature on fixed point theorems within these contexts is constrained in several ways. The available literature has notable shortcomings; consequently, this article investigates the results and implications of contractive mappings in complex-valued b-metric spaces by utilizing weak compatible mappings, and it also employs control functions while solving a system of Urysohn integral equations based on our primary result. These findings contribute to this area of study.  

 

Cite: Shivani Chourasiya, Harshit Khare, Kavita Shrivastava   COMMON FIXED POINT THEOREMS IN COMPLEX VALUED B-METRIC SPACES AND USING WEAK COMPATIBLE MAPPINGS . Reliability: Theory & Applications. 2025, June 2(84):  271-281, DOI: https://doi.org/10.24412/1932-2321-2025-284-271-281.


 

 

 

ESTIMATION AND APPLICATION OF A NEW GENERALIZATION OF EXPONENTIAL DISTRIBUTION 

282-294

 

 

D. Kumar, P. K. Chaurasia, P. Kumar, A. Sahoo  

 

 

 

In statistical literature, several lifetime distributions exist for real phenomena. And one of the methods to find new lifetime distribution by existing baseline distribution such a method is known as the transformation method. In this article, we proposed a generalization of the existing transformation by introducing the additional shape parameter. Here, we considered baseline distributions as an exponential distribution. Various statistical properties of the new lifetime distribution, such as survival function, hazard rate function, cumulative hazard rate function, moments, quantile function, and order statistics, have been discussed. Demonstrate the applicability and suitability of the proposed distribution. Here, we focus only on the estimation of the parameters likes MLE, LSE and also to check long-run behaviour of the estimators.  

 

Cite: D. Kumar, P. K. Chaurasia, P. Kumar, A. Sahoo   ESTIMATION AND APPLICATION OF A NEW GENERALIZATION OF EXPONENTIAL DISTRIBUTION . Reliability: Theory & Applications. 2025, June 2(84):  282-294, DOI: https://doi.org/10.24412/1932-2321-2025-284-282-294.


 

 

 

PARABOLIC DENSE CLOUDY FUZZY MODEL WITH DEMAND DEPENDENT PRODUCTION RATE IN AN IMPRECISE PRODUCTION PROCESS

295-307

 

 

Upsana Rana, Tanuj Kumar  

 

 

 

In this paper we develop a classical economic production lot size model of a manufactured item in a inadequate production process in which the ordering cost is fixed and shortage is not allowed. In this model the valuation of an item is considered as a parabolic cloudy fuzzy number and production rate is depends on demand. In the previous studies, fuzziness of parameters of the model is presented in the form of fuzzy numbers using the membership function only. Parabolic dense cloudy intuitionistic fuzzy numbers are found to be more generalized than fuzzy numbers and have the capability to express the fuzziness of parameters of the model in a more generalized way using both membership and non-membership functions. The presented model is solved in crisp, fuzzy and Intuitionistic fuzzy setup using proposed generalize and defuzzification method with minimum loss of data. The present model is solved by DBPSO algorithm to determine optimal values. The validity of the proposed model and parameter sensitivity analysis is presented to justify the idea by the numerical analysis.  

 

Cite: Upsana Rana, Tanuj Kumar   PARABOLIC DENSE CLOUDY FUZZY MODEL WITH DEMAND DEPENDENT PRODUCTION RATE IN AN IMPRECISE PRODUCTION PROCESS. Reliability: Theory & Applications. 2025, June 2(84):  295-307, DOI: https://doi.org/10.24412/1932-2321-2025-284-295-307.


 

 

 

RELIABILITY AVAILABILITY MAINTAINABILITY DEPENDABILITY (RAMD) OPTIMIZATION: A CASE STUDY OF MANUFACTURING PLANT

308-323

 

 

Deepika Garg, Dipesh Popli, Pradeep Kamboj, Nakul Vashishth  

 

 

 

In the context of modern Industry practices, optimizing the performance of complex systems necessitates a thorough understanding of Reliability, Availability, Maintainability, and Dependability (RAMD). This paper dives into the application of two powerful optimization techniques, Genetic Algorithm (GA) and Particle Swarm Optimization (PSO), in RAMD optimization. GA, a simulation of natural evolution, employs selection, crossover, and mutation operations to search for optimal solutions iteratively. In contrast, PSO replicates the collective behavior of a swarm, iteratively updating particle positions based on their best position and the swarm’s best position. The research specifically focuses on RAMD optimization in terms of maintenance schedules, resource allocation, and system configurations. The results from both techniques are compared, with PSO demonstrating superior performance. The paper concludes by underscoring the need for further research and practical implementation of PSO and GA to fully exploit their potential in optimizing RAMD parameters across diverse domains.  

 

Cite: Deepika Garg, Dipesh Popli, Pradeep Kamboj, Nakul Vashishth   RELIABILITY AVAILABILITY MAINTAINABILITY DEPENDABILITY (RAMD) OPTIMIZATION: A CASE STUDY OF MANUFACTURING PLANT. Reliability: Theory & Applications. 2025, June 2(84):  308-323, DOI: https://doi.org/10.24412/1932-2321-2025-284-308-323.


 

 

 

ON THE PROTECTION AGAINST NOISE FOR MEASUREMENT-BASED QUANTUM COMPUTATION

324-331

 

 

Valentin Vankov Iliev  

 

 

 

In this paper we establish conditions for some pairs of quantum logic gates which operate on one qubit to be protected against crosstalk. We represent these logic gates by self-adjoint operators acting on an unitary plane, consider the resembling bipartite quantum systems, and extend the operators naturally to a commuting pair. Thus the corresponding two measurements can be considered as simultaneous and we can define them as events in a classical probability space. In particular, we are able to study their dependence, the information noise thus produced, and to find necessary and sufficient conditions for being informationally independent events.  

 

Cite: Valentin Vankov Iliev   ON THE PROTECTION AGAINST NOISE FOR MEASUREMENT-BASED QUANTUM COMPUTATION. Reliability: Theory & Applications. 2025, June 2(84):  324-331, DOI: https://doi.org/10.24412/1932-2321-2025-284-324-331.


 

 

 

HIDDEN MARKOV MODELS FOR ESTIMATING IMPORT DYNAMICS WITH PROBABILITY DISTRIBUTION ANALYSIS

332-346

 

 

Vyshnavi. M, Muthukumar. M  

 

 

 

This article examines the use of Hidden Markov Models and probability distributions to study agricultural import dynamics, with a focus on revealing hidden patterns in the data. The idea behind the study is to enhance our understanding of how transitions between different agricultural import states occur and to explore the most suitable probability distributions for modeling these hidden states. The purpose of the study is to identify the optimal distributional fit for hidden states by evaluating the Transition Probability Matrix, Emission Probability Matrix, and Initial Probability Vector (π) for each state. The research implements the Akaike Information Criterion and the Bayesian Information Criterion to select the best-fitting distribution for each scenario. Furthermore, the paper focuses on the practical implications of these discoveries, such as determining the most likely state sequence using the Viterbi path, which can help influence decision-making and forecasting. The analysis is carried out using R software, which provides information about the associations between probability distributions, stationarity tests, and the role of model selection criteria such as AIC and BIC. Graphical representations of AIC and BIC values over several probability distributions, and additionally a correlation matrix between selected distributions, help to highlight the findings. Overall, the paper enhances our understanding of probability distributions through HMM frameworks for agricultural import dynamics, providing recommendations for optimal model selection in various applications.  

 

Cite: Vyshnavi. M, Muthukumar. M   HIDDEN MARKOV MODELS FOR ESTIMATING IMPORT DYNAMICS WITH PROBABILITY DISTRIBUTION ANALYSIS. Reliability: Theory & Applications. 2025, June 2(84):  332-346, DOI: https://doi.org/10.24412/1932-2321-2025-284-332-346.


 

 

 

OPTIMIZED SCHEDULING FOR THREE-STAGE FLOW SHOP WITH PARALLEL MACHINES: APPLICATION IN WASTE MANAGEMENT AND RECYCLING FACILITIES

347-357

 

 

Sonia, Pooja kaushik, Deepak Gupta, Sonia Goel  

 

 

 

Scheduling is one of the most important aspects of manufacturing sectors. Various factors in terms of performance evaluation, make business more competitive. Scheduling is the process of allocating scarce resources to tasks throughout time in order to accomplish one or more optimization goals. In fact, the methodical process of organizing, managing and maximizing work while ensuring the greatest possible use of both time and resources is the main aim of scheduling. This paper indicates the desirable and necessary steps to discover the optimum solution by efficient scheduling in waste recycling facilities which is essential for optimizing resources utilization and reducing operational delay. In this study, we have taken three stage flow shop scheduling with multiple machines at first two stages and single machine at last stage. This type of model has a number of applications not only in several industries but also in saving natural resources like water, electricity and reducing waste, idle time and unnecessary energy consumption. As, this research specially focused on the scenario of waste management and recycling facility where incoming waste undergoes three primary stages sorting, cleaning, and recycling. Here the scheduling evaluation is done by comparing the Branch and Bound method with Palmer’s and Dannenbring method to determine an optimal job sequence that minimize the total processing time. The processing time is represented as a trapezoidal fuzzy number making an impact. The goal of this activity is to determine the optimal job plan in order to reduce the total amount of time that has processed and allocate the lead in the best feasible way to reduce the machine idle time, minimizes the water usage and energy consumption. This comparison demonstrated how well our suggested approach handled this challenging scheduling issue the findings contribute to the efficient management of recycling facilities, ensuring improved throughput. Because better scheduling strategies must be implemented in order to the growing demand for waste processing and recycling. So, the proposed approach aids in streamlining waste management processes, ultimately supporting environmental conservation efforts. Here, Branch and Bound is the best approach as compared to Palmer and Dannenbring approach. Future work can be extending this methodology to the three-phase flow shop scheduling with parallel machines at all the stages.  

 

Cite: Sonia, Pooja kaushik, Deepak Gupta, Sonia Goel   OPTIMIZED SCHEDULING FOR THREE-STAGE FLOW SHOP WITH PARALLEL MACHINES: APPLICATION IN WASTE MANAGEMENT AND RECYCLING FACILITIES. Reliability: Theory & Applications. 2025, June 2(84):  347-357, DOI: https://doi.org/10.24412/1932-2321-2025-284-347-357.


 

 

 

RELIABILITY MEASURES AND CLASSICAL AND BAYESIAN PARAMETRIZATION OF TWO NON-IDENTICAL UNITS SYSTEM MODEL WITH ON-LINE/OFF-LINE REPAIRS OF REPAIR MACHINE

358-371

 

 

Poonam Sharma, Pawan Kumar, Shallu Sharma

 

  

 

The present paper deals with the reliability analysis of a system model which consists of two non identical units and a repair machine. One of the units initially, is in operative mode and other is kept in standby mode. Repair machine is initially in good condition, it may fails while repairing the failed units. In case of failure of repair machine, firstly it undergoes on-line repair and then to off-line repair if not repaired online. The failure time distributions of both the units and repair machine are assumed to be exponential while the repair time distributions are taken as general. By using regenerative point techniques, various measures of system effectiveness such as transition probabilities, MTSE, reliability, availability, busy period etc. have been obtained. Also, some of them have been studied graphically. A simulation study is also carried out to analyse the considered system model both in Classical and Bayesian setups. From the graphs and tables, various important conclusions are drawn.  

 

Cite: Poonam Sharma, Pawan Kumar, Shallu Sharma RELIABILITY MEASURES AND CLASSICAL AND BAYESIAN PARAMETRIZATION OF TWO NON-IDENTICAL UNITS SYSTEM MODEL WITH ON-LINE/OFF-LINE REPAIRS OF REPAIR MACHINE. Reliability: Theory & Applications. 2025, June 2(84):  358-371, DOI: https://doi.org/10.24412/1932-2321-2025-284-358-371.


 

 

 

DEVELOPMENT OF AN ATTRIBUTE CONTROL CHART BASED ON THE INVERSE KUMARASWAMY DISTRIBUTION

372-381

 

 

Nagaraju, R., Palanivel, M., Sriramachandran, G. V.  

 

 

 

This article presents the development of an attribute control chart designed for products with lifespans following the inverse Kumaraswamy distribution, using the distribution’s mean as the quality metric. The study assumes one distribution parameter is known while varying the other to design the control chart. The chart’s performance is evaluated using Average Run Length (ARL), with adjustments to parameter values determining ARL in out-of-control conditions. The proposed control chart is assessed through simulations. A comparative analysis with other similar charts is conducted based on ARL values, and the findings are discussed in detail.  

 

Cite: Nagaraju, R., Palanivel, M., Sriramachandran, G. V.   DEVELOPMENT OF AN ATTRIBUTE CONTROL CHART BASED ON THE INVERSE KUMARASWAMY DISTRIBUTION. Reliability: Theory & Applications. 2025, June 2(84):  372-381, DOI: https://doi.org/10.24412/1932-2321-2025-284-372-381.


 

 

 

ASSESSMENT OF POSSIBLE SEISMIC HAZARD AND RISK USING THE EXAMPLE OF ALMATY

382-393

 

 

Gennadii Nigmetov, Andrey Savinov, Temir Nigmetov, Syrym Gabbasov

 

  

 

In January 2024, residents of Almaty felt the seismic impact of an earthquake that occurred on the border of China and Kyrgyzstan. The city was not prepared for such an event. How could the city residents prepare for this devastating earthquake? In order to properly prepare the population for a destructive earthquake, it is necessary to have a system for assessing the individual seismic risk of the city, which uses data for risk assessment: on predicted possible earthquake sources (PES) dangerous for the city for the next 10 years, on the seismic resistance of buildings and the city’s population. Based on these data, the possible individual risk for the city population is assessed. In order to assess the individual risk as accurately as possible, in addition to data on the PES and seismic resistance of buildings, data on the macroseismic field from the PES forecast are needed. At present, there are all the necessary scientific and technical capabilities for creating monitoring systems for seismic protection of cities.  

 

Cite: Gennadii Nigmetov, Andrey Savinov, Temir Nigmetov, Syrym Gabbasov ASSESSMENT OF POSSIBLE SEISMIC HAZARD AND RISK USING THE EXAMPLE OF ALMATY. Reliability: Theory & Applications. 2025, June 2(84):  382-393, DOI: https://doi.org/10.24412/1932-2321-2025-284-382-393.


 

 

 

AN APPLICATIONS-BASED STOCHASTIC MODELING OF MIXTURE DISTRIBUTION FOR CANCER DATA

394-407

 

 

Pooyitha R and Pandiyan P

 

  

 

This study proposed a new stochastic model by the mixture of Gamma and Zeghdoudi distribution (MGZ Distribution). The Reliability Analysis and statistical features such as moments, Moment generating function, order statistics, stochastic ordering, entropy, and the Maximum Likelihood Estimation of the model parameters were derived. Two real-time datasets of cancer patients' survival times were used to demonstrate the model's goodness-of-fit using the AIC, BIC, and AICC model selection methods. The new MGZ model has been compared with the other classical models like Exponential, Lindley and Shanker. The result shows that the proposed model is more flexible than the other models with the lowest values of AIC, BIC and AICC.  

 

Cite: Pooyitha R and Pandiyan P AN APPLICATIONS-BASED STOCHASTIC MODELING OF MIXTURE DISTRIBUTION FOR CANCER DATA. Reliability: Theory & Applications. 2025, June 2(84):  394-407, DOI: https://doi.org/10.24412/1932-2321-2025-284-394-407.


 

 

 

HIGH-TEMPERATURE HEAT-INSULATING MATERIALS: A COMPROMISE BETWEEN THERMAL CONDUCTIVITY AND RELIABILITY 

408-413

 

 

N.M. Piriyeva, R.K. Karimova, G.K. Abdullayeva

 

  

 

This article examines heat transfer mechanisms in high-temperature thermal insulation materials, addressing key operational challenges such as thermal degradation, mechanical stability, and chemical resistance. The novelty of the study lies in an integrated approach that includes optimizing the micro- and nanostructure to minimize radiative and conductive heat transfer, developing advanced multilayer and composite systems, applying predictive computational modeling for property assessment, and exploring self-healing coatings and intelligent materials. These innovations ensure reduced thermal conductivity without compromising mechanical strength, enhance resistance to thermal cycling and aggressive chemical exposure, and significantly extend the service life of insulation systems, making them highly promising for aerospace, energy, metallurgy, and other industries requiring reliable thermal protection. Additionally, the proposed solutions contribute to increased energy efficiency, reduced material consumption, and improved environmental sustainability, paving the way for next-generation thermal insulation technologies with broader industrial applicability.  

 

Cite: N.M. Piriyeva, R.K. Karimova, G.K. Abdullayeva HIGH-TEMPERATURE HEAT-INSULATING MATERIALS: A COMPROMISE BETWEEN THERMAL CONDUCTIVITY AND RELIABILITY . Reliability: Theory & Applications. 2025, June 2(84):  408-413, DOI: https://doi.org/10.24412/1932-2321-2025-284-408-413.


 

 

 

EVALUATING MULTI SERVER QUEUING SYSTEM EFFICIENCY: A COMPARATIVE STUDY BETWEEN FUZZY QUEUING MODEL AND INTUITIONISTIC FUZZY QUEUING MODEL WITH INFINITE CAPACITY CONSTRAINTS

414-428

 

 

S. Aarthi  

 

 

 

In this study, we suggest an innovative analytical approach employing triangular fuzzy and triangular intuitionistic fuzzy numbers to ascertain the membership functions governing significant service-execution proportions within multiserver queuing models. Departing from conventional methodologies, both the inter-entry and completion rates are characterized by fuzzy natures, introducing a novel dimension to the analysis. Through numerical validation, our model demonstrates viability in the multiserver queuing context, bolstering its credibility. Furthermore, we conduct a contextual investigation, juxtaposing individual fuzzy metrics, thereby revealing the superior categorization potential of intuitionistic fuzzy queuing models over their fuzzy counterparts. Expanding the horizons of traditional fuzzy queuing theory, our integration of intuitionistic fuzzy environments promises enhanced queuing model implementation efficacy. Our primary objective lies in evaluating the productivity of a multi-server queuing model with limitless capacity, leveraging both fuzzy queuing and intuitionistic fuzzy queuing theories. Embracing a framework where arrival and service rates are characterized by triangular and intuitionistic triangular fuzzy numbers, we undertake a thorough assessment to establish evaluation criteria, adhering to a design protocol that preserves fuzzy values without converting them into crisp values. Additionally, we address two statistical challenges to ascertain the method's validity.  

 

Cite: S. Aarthi   EVALUATING MULTI SERVER QUEUING SYSTEM EFFICIENCY: A COMPARATIVE STUDY BETWEEN FUZZY QUEUING MODEL AND INTUITIONISTIC FUZZY QUEUING MODEL WITH INFINITE CAPACITY CONSTRAINTS. Reliability: Theory & Applications. 2025, June 2(84):  414-428, DOI: https://doi.org/10.24412/1932-2321-2025-284-414-428.


 

 

 

FORECASTING VOLATILITY IN INDIAN NATIONAL STOCK EXCHANGE USING A MARKOV SWITCHING GARCH MODEL

429-446

 

 

D. Pachiyappan, S. Jayabharathi, Y. Geeyha Evanjalin, S. Kavitha

 

  

 

This paper analyzes various GARCH models in terms of their effectiveness in predicting volatility in the national Stock Exchange (NSE). This paper examines GARCH models that feature both Gaussian and fat-tailed residual conditional distributions, and evaluates their ability to characterize and predict volatility over time horizons ranging from 1 to 22 days. The AR(2)-MR-SGARCH-GED model demonstrates superior performance compared to other models at a one-day horizon. The AR(2)-MR-SGARCH-GED and AR(2)-MRSGARCH+ models surpass other models at the 5-day horizon. Within a ten-day timeframe, three AR(2)-MR-SGARCH models surpass the performance of alternative models. Regarding the 22-day forecast horizon, the results demonstrate no distinctions between MR-SGARCH models and standard GARCH models. When looking at risk management outside of samples (95% VaR), a number of models seem to give accurate and reasonable VaR estimates for a one-day period, with a coverage rate close to the nominal level. According to the risk management loss functions, no model is universally the most accurate. This variability suggests that model performance is context-dependent, influenced by the specific characteristics of the data and the underlying assumptions of each approach. Therefore, practitioners should consider employing a combination of models to enhance robustness in their risk assessments and decision-making processes. 

 

 

Cite: D. Pachiyappan, S. Jayabharathi, Y. Geeyha Evanjalin, S. Kavitha FORECASTING VOLATILITY IN INDIAN NATIONAL STOCK EXCHANGE USING A MARKOV SWITCHING GARCH MODEL. Reliability: Theory & Applications. 2025, June 2(84):  429-446, DOI: https://doi.org/10.24412/1932-2321-2025-284-429-446.


 

 

 

MULTI REFERENCE SKIP-LOT SAMPLING PLAN: A NOVEL APPROACH FOR QUALITY CONTROL

447-455

 

 

Meby Joseph Manoj, Azarudheen S  

 

 

 

Skip-lot sampling plans have become significant in modern quality control due to rising production volumes and the demand for cost-effective inspection methods that will yield high-quality outputs. When inspecting a submitted lot, a skip-lot plan is economically favourable and guarantees high quality. Thus, this approach benefits both producers and consumers. The skip-lot sampling plan generally utilizes the same sampling plan as the reference plans for both skipping and normal inspection. However, using the same plan in both phase favours either the producer or the consumer in the most essential situations. This article introduces a novel approach, the Multi Reference Skip-Lot Sampling Plan with the provision of having two different reference plans in the normal and skipping phases of the skip-lot plan. The paper explores the efficacy of this approach by deriving performance measures using a power series approach. To evaluate the proposed plan, a comparison is made with existing skip-lot sampling plans that use single sampling plans or double sampling plans as reference plans. This comparison is based on operational characteristics and average sample number values, accompanied by graphical representations. The comparative analysis demonstrates that the new plan effectively balances the satisfaction of both producers and consumers. Additionally, the study offers a strategy for selecting the plan parameters using the unity value approach, supported by a table providing unity values.  

 

Cite: Meby Joseph Manoj, Azarudheen S   MULTI REFERENCE SKIP-LOT SAMPLING PLAN: A NOVEL APPROACH FOR QUALITY CONTROL. Reliability: Theory & Applications. 2025, June 2(84):  447-455, DOI: https://doi.org/10.24412/1932-2321-2025-284-447-455.


 

 

 

MARSHALL - OLKIN TWO PARAMETER SUJATHA DISTRIBUTION AND ITS APPLICATIONS

456-465

 

 

V. Sreejith, Ajitha Sasi, B. Vineshkumar

 

 

 

Sujatha distribution, often discussed in the context of reliability engineering and survival analysis, is a probability distribution that is useful for modeling lifetimes of objects and systems. In this paper, we introduce a three parameter distribution called the Marshall - Olkin two parameter Sujatha distribution. Marshall - Olkin generalization is a novel method of enlarging a known family of distributions. It leads to a rich class of distributions that can capture different shapes and behaviours and thus allows for better fitting to empirical data, thereby establishing its importance in reliability engineering. We derive many useful statistical properties such as the hazard rate function, reverse hazard rate function, order statistics, moments, measure of skewness and measure of kurtosis of the Marshall - Olkin two parameter Sujatha distribution. The stress - strength reliability of this distribution has also been derived. The application of this new distribution is established using real life data sets. We also compare the performance of this distribution with that of some existing distributions.  

 

Cite: V. Sreejith, Ajitha Sasi, B. Vineshkumar MARSHALL - OLKIN TWO PARAMETER SUJATHA DISTRIBUTION AND ITS APPLICATIONS. Reliability: Theory & Applications. 2025, June 2(84):  456-465, DOI: https://doi.org/10.24412/1932-2321-2025-284-456-465.


 

 

 

A NEW GENERALIZATION OF PARETO DISTRIBUTION: PROPERTIES AND APPLICATIONS 

466-478

 

 

Tabasum Ahad, S.P. Ahmad

 

 

 

This manuscript introduces a new extension of the Pareto distribution using the SMP transformation technique, known as SMP Pareto distribution (SMPP). The SMP technique is named after (Shamshad, Murtiza, Parvaiz) who pioneered this approach to enhance the flexibility and applicability of statistical models. This new distribution provides a better fit for data than many existing models. The shapes of the density function exhibit great flexibility. It can support different hazard shapes, such as increasing, decreasing and constant shapes. Various statistical properties of the proposed distribution such as moments, quantile function, entropy and order statistics were presented. The maximum likelihood technique is used to estimate the model parameters. An extensive simulation study is carried out to illustrate the behavior of MLEs. In addition, two real-world datasets are analyzed to showcase the applicability of the proposed approach. The results indicate that the SMP Pareto distribution (SMPP) is more flexible and offers a superior fit for describing data compared to several existing forms of the Pareto distribution.  

 

Cite: Tabasum Ahad, S.P. Ahmad A NEW GENERALIZATION OF PARETO DISTRIBUTION: PROPERTIES AND APPLICATIONS . Reliability: Theory & Applications. 2025, June 2(84):  466-478, DOI: https://doi.org/10.24412/1932-2321-2025-284-466-478.


 

 

 

FUZZY DATA-DRIVEN ESTIMATION FOR DUAL WEIBULL POPULATIONS: EM AND BAYESIAN METHODS WITH GIBBS SAMPLING 

479-492

 

 

Abbarapu Ashok and Nadiminti Nagamani

 

  

 

In statistical analysis, accurately estimating parameters in the presence of uncertain and imprecise data is critical, particularly when dealing with complex, dual population models. Fuzzy data, which effectively represents real-world ambiguity, provides a framework for handling such uncertainties. While parameter estimation for single-population models with fuzzy data has been explored extensively, extending these methods to dual populations remains challenging. This study addresses this gap by developing estimation techniques for two Weibull populations that share a common shape parameter but differ in scale parameters, under fuzzy data conditions. We employ the Expectation-Maximization (EM) algorithm for Maximum Likelihood estimation and a Bayesian framework with TK approximation for parameter estimation. To refine our Bayesian estimates, we use Gibbs sampling to compute posterior densities. Through Monte Carlo simulations, for generated data as well as for a real dataset, we evaluate the accuracy and robustness of the proposed estimators, demonstrating their practical utility in applications where data imprecision is a significant factor. This research highlights the importance of robust methodologies for dual-population Weibull models, contributing to enhanced reliability in statistical analysis across diverse fields.  

 

Cite: Abbarapu Ashok and Nadiminti Nagamani FUZZY DATA-DRIVEN ESTIMATION FOR DUAL WEIBULL POPULATIONS: EM AND BAYESIAN METHODS WITH GIBBS SAMPLING . Reliability: Theory & Applications. 2025, June 2(84):  479-492, DOI: https://doi.org/10.24412/1932-2321-2025-284-479-492.


 

 

 

ACCELERATED FAILURE TIME MODELING FOR PROGNOSTIC FACTORS IN MALE DIABETES PATIENTS: A COMPARATIVE ANALYSIS OF SURVIVAL MODELS 

493-502

 

 

Jeslin J, Radhika A, Haripriya M  

 

 

 

Accelerated Failure Time Models (AFTMs) are utilized to examine survival patterns, particularly in the context of diseases such as diabetes, where traditional models like Cox proportional hazards may not apply. In this study, we apply AFTMs to identify significant prognostic factors affecting survival in male diabetic patients, using parametric distributions such as Exponential, Weibull, Log-normal, and Log-logistic. The primary objective of this study is to gain deeper insights into how key covariates influence survival times and enhance risk stratification, ultimately leading to better treatment outcomes. We evaluated the fit of several AFTMs by comparing Log-Likelihood, Akaike Information Criterion (AIC), and Bayesian Information Criterion (BIC) values. Among the models tested, the Weibull AFTM emerged as the best fit, demonstrating superior Log-Likelihood and lower AIC and BIC values compared to other distributions. The study identified several significant predictors of survival in male diabetic patients, including age, family history of diabetes, duration of diabetes, early use of insulin (within one year of diagnosis), retinopathy, use of diuretics, proteinuria, hypertension, and fasting plasma glucose levels. All of these covariates were found to significantly influence survival outcomes (\(P<0.05\)), with older age and longer diabetes duration correlating with poorer survival rates. These findings underscore the importance of using AFTMs to model survival patterns in diabetic patients and the potential for targeted interventions based on identified risk factors. While the small sample size limits the generalizability of the results, this study provides valuable insights into the survival characteristics of male diabetic patients and highlights the need for further research with larger datasets. Future studies should consider a wider range of covariates and explore the application of AFTMs in broader diabetic populations to refine survival prediction models and optimize patient care. Additionally, integrating machine learning techniques with AFTMs could enhance predictive accuracy and provide a more comprehensive understanding of survival trends in diabetic patients.  

 

Cite: Jeslin J, Radhika A, Haripriya M   ACCELERATED FAILURE TIME MODELING FOR PROGNOSTIC FACTORS IN MALE DIABETES PATIENTS: A COMPARATIVE ANALYSIS OF SURVIVAL MODELS . Reliability: Theory & Applications. 2025, June 2(84):  493-502, DOI: https://doi.org/10.24412/1932-2321-2025-284-493-502.


 

 

 

PERFORMANCE EVALUATION AND OPTIMIZATION OF CRYSTALLIZATION AND SUGAR HANDLING SUBSYSTEMS IN SUGAR MILL PLANT USING PSO

503-517

 

 

Sandeep Kumar, Vikas Modgil

 

 

 

An appropriate maintenance strategy is necessary for sugar mill plants and particularly focuses on the core processing system. This research creates an availability-based simulation model for a sugar mill with 25,500 tons sugarcane crushing capacity. A Markov performance evaluation approach is used, and differential equations generated from a transition diagram covering fully operational, partially operational, and failure modes are included. Among the major processing units, the Evaporator is identified as a core processing component, being directly involved in sugar concentration. In contrast, the Rotary Dryer and the Centrifugal Machine (Batch or Continuous Centrifuge) are classified as auxiliary units. These support the production process by reducing moisture content and separating sugar from molasses, respectively, without altering the sugar chemically. The Crystallizer (e.g., A-Pan Crystallizer) is also a core processing component, directly responsible for crystal formation. PSO is used to improve performance by optimizing the failure and repair rates and enhancing the performance metrics. Experimental results showed the system achieved 88.84% availability. These results allow maintenance strategies that focus on the most critical subsystems to be processing developed. A case for focused maintenance is made based on the evidence provided for more effective scheduling, ultimately improving system performance.  

 

Cite: Sandeep Kumar, Vikas Modgil  PERFORMANCE EVALUATION AND OPTIMIZATION OF CRYSTALLIZATION AND SUGAR HANDLING SUBSYSTEMS IN SUGAR MILL PLANT USING PSO. Reliability: Theory & Applications. 2025, June 2(84):  503-517, DOI: https://doi.org/10.24412/1932-2321-2025-284-503-517.


 

 

 

ASSESSING THE PREDICTIVE RESILIENCE OF COMPOSITE EXPERIMENTAL DESIGNS UNDER MISSING OBSERVATIONS: THE INFLUENCE OF A ALPHA VALUE VARIATIONS

518-534

 

 

A.R. Gokul and M. Pachamuthu

 

 

 

Withdrawal

 

 

 

FIXED POINT THEOREMS FOR SEQUENCE OF MAPPINGS IN TRICOMPLEX VALUED METRIC SPACE

535-546

 

 

Shivani Chourasiya, Kavita Shrivastava

 

 

 

Fixed point theory plays a crucial role in mathematical analysis, with profound applications in differential equations, optimization, and dynamic systems. Over the years, researchers have extended classical fixed point results to more complex structures, such as tricomplex valued metric spaces, to address problems in multidimensional and hypercomplex settings. Despite the growing interest in tricomplex variable spaces, existing literature on fixed point theorems within these frameworks remains limited by various constraints. The existing literature exhibits several limitations; therefore, in this article, we utilize the concepts of continuity and weak compatibility to establish fixed point results for a novel class of contraction mappings by employing a sequence of mappings within a tricomplex valued metric space. If two mappings commute at their point of coincidence, they are said to be weakly compatible. These results not only deepen the comprehension of fixed point theory but also open up new possibilities for its application in more intricate and varied mathematical contexts. As a result, our research progresses in the field, providing a solid foundation for future investigations and potential uses across multiple scientific and engineering domains.  

 

Cite: Shivani Chourasiya, Kavita Shrivastava FIXED POINT THEOREMS FOR SEQUENCE OF MAPPINGS IN TRICOMPLEX VALUED METRIC SPACE. Reliability: Theory & Applications. 2025, June 2(84):  535-546, DOI: https://doi.org/10.24412/1932-2321-2025-284-535-546.


 

 

 

DISCOUNT PRICING POLICY WITH STOCHASTIC DEMAND AND PRESERVATION TECHNOLOGY FOR DETERIORATING ITEMS

547-561

 

 

Ramkrishna Tiwari, Ram Kumar Tiwari, Lalji Kumar, Pooran Lal Prajapati, Utram Kumar Khedlekar  

 

 

 

Managing inventory for deteriorating items presents significant challenges, especially in environments where demand is stochastic and price-sensitive. Retailers face the dual pressure of minimizing losses from product deterioration while ensuring sufficient stock availability to meet customer demand. Additionally, backlogged shortages, if not managed strategically, can erode customer satisfaction and profitability. These complexities are further compounded by the need to strike a balance between promotional efforts, preservation investments, and pricing strategies to remain competitive in dynamic markets. To address these challenges, this study develops a comprehensive mathematical model aimed at optimizing replenishment strategies for deteriorating items. The model integrates preservation technologies and strategic price discounts to enhance product demand while accounting for the intricate relationship between market potential, stock levels, promotional efforts, and selling prices. The objective is to determine optimal pricing policies, order quantities, promotional expenditures, preservation costs, and schedules for shortages and replenishment, ultimately maximizing total profit per unit time. The findings reveal that total profit per unit time is concave concerning price, shortage duration, and inventory holding period. Numerical analyses demonstrate the efficacy of preservation technologies in mitigating deterioration rates, enabling retailers to adopt competitive pricing and stimulate sales. Additionally, the demand pattern index is shown to significantly influence inventory policies, while promotional campaigns play a critical role in augmenting product sales. Quantity discounts, tied to demand and order volumes, are identified as effective tools for reducing procurement costs and enhancing retailer profitability. These insights highlight the strategic importance of investing in preservation technologies, adopting dynamic pricing strategies, and implementing targeted promotional campaigns. Together, these approaches provide a robust framework for optimizing inventory management, increasing sales, and maximizing profitability in highly competitive markets.  

 

Cite: Ramkrishna Tiwari, Ram Kumar Tiwari, Lalji Kumar, Pooran Lal Prajapati, Utram Kumar Khedlekar   DISCOUNT PRICING POLICY WITH STOCHASTIC DEMAND AND PRESERVATION TECHNOLOGY FOR DETERIORATING ITEMS. Reliability: Theory & Applications. 2025, June 2(84):  547-561, DOI: https://doi.org/10.24412/1932-2321-2025-284-547-561.


 

 

 

CAUSES OF ELECTROMECHANICAL RESONANCE IN WIND TURBINES AND METHODS FOR ITS ELIMINATION

562-569

 

 

N.S. Mammadov  

 

 

 

Electromechanical resonance in wind turbines is a complex and multifaceted phenomenon that significantly affects the performance, service life, and reliability of wind turbines. This problem is especially relevant for modern high-power wind turbines operating under variable loads and high air turbulence. The article provides a detailed analysis of the mechanisms of electromechanical resonance, including the influence of design parameters, aerodynamic loads, electromagnetic interactions, and operating conditions. The physical foundations of resonance phenomena and their impact on the dynamic behavior of wind turbines are considered, which allows for a deeper understanding of the mechanisms of their occurrence and the development of methods for their prevention. Particular attention is paid to modern methods of diagnostics and prediction of resonance effects. The existing technologies for suppressing resonance oscillations are analyzed, such as the use of damping elements, active vibration dampers, adaptive control systems, and digital twins, which allow for real-time prediction and correction of generator behavior. In addition, the article proposes innovative engineering solutions aimed at increasing the stability of wind turbines to resonance phenomena. These solutions include optimizing design parameters, selecting new high-strength and damping materials, and improving automated control systems. Research into this problem and developing effective measures to eliminate it are key aspects of further development of wind energy, allowing for an increase in the service life of equipment, its reliability, and a reduction in operating costs.  

 

Cite: N.S. Mammadov   CAUSES OF ELECTROMECHANICAL RESONANCE IN WIND TURBINES AND METHODS FOR ITS ELIMINATION. Reliability: Theory & Applications. 2025, June 2(84):  562-569, DOI: https://doi.org/10.24412/1932-2321-2025-284-562-569.


 

 

 

MINIMIZATION OF ACTIVE POWER LOSSES IN ALTERNATING CURRENT MAGNETIC SYSTEMS 

570-576

 

 

G.V. Mamedova  

 

 

 

In magnetic systems of electromagnetic alternating current devices, active power losses occur in steel and copper, reducing which is an urgent task. In order to minimize the loss of active power, a method based on the geometric optimization of the magnetic system has been developed. The optimization criteria are the coefficients of the proportionality principle. The last requirement is necessary for the proper coordination of the designed device with other mechanisms and for improving the technical and economic performance of the devices. One of the proportionality principles for electromagnetic devices is the construction of designs with a given coefficient \( n_0 = h\omega_{co} \), where \( h\omega_{co} \) and are the height and thickness of the winding, respectively, as the overall dimensions of the device are mainly determined by these parameters. As a rule, the value of the coefficient \( n_0 \) can be ensured after the preliminary calculation of the magnetic circuit. On the other hand, there are complex interrelations between the coefficient \( n_0 \) and the temperature rise of the winding. Excessive increase or decrease of the coefficient \( n_0 \) disrupts this principle, reduces the current density in the winding, increases the cross-section of the material and the winding capacity, and fails to achieve the specified temperature rise of the winding, etc. In this case, the main task of optimizing the winding dimensions is to ensure the maximum current density in the winding while maintaining the given coefficient \( n_0 \), temperature rise, and the ampere-turn values obtained from the preliminary calculation. In this study, for the most common electromagnetic design, considering the given ratios of winding height to its thickness, temperature rise, and ampere-turns, the optimal parameters and dimensions of the magnetic system have been determined. Loss minimization has been carried out for electromagnetic devices with voltage winding and current winding.  

 

Cite: G.V. Mamedova   MINIMIZATION OF ACTIVE POWER LOSSES IN ALTERNATING CURRENT MAGNETIC SYSTEMS . Reliability: Theory & Applications. 2025, June 2(84):  570-576, DOI: https://doi.org/10.24412/1932-2321-2025-284-570-576.


 

 

 

STEADY STATE ANALYSIS OF BULK ARRIVAL, FIXED BATCH SERVICE QUEUE WITH INSPECTION, REWORK AND MULTIPLE VACATIONS

577-589

 

 

S. Karpagam, R. Lokesh  

 

 

 

A non-Markovian bulk queueing system receives bulk arrivals through a single server that handles fixed-size batch services. The server conducts quality checks after each service to identify defective items, which are then sent to rework for quality control purposes. The server takes random-length vacations until new arrivals reach the threshold "K" before returning to service. Through the supplementary variable technique, the key performance metrics are computed together with steady-state governing equations. Using graphical representations and numerical tables, the model demonstration shows essential information about system performance through calculated data.  

 

Cite: S. Karpagam, R. Lokesh   STEADY STATE ANALYSIS OF BULK ARRIVAL, FIXED BATCH SERVICE QUEUE WITH INSPECTION, REWORK AND MULTIPLE VACATIONS. Reliability: Theory & Applications. 2025, June 2(84):  577-589, DOI: https://doi.org/10.24412/1932-2321-2025-284-577-589.


 

 

 

ANALYSIS OF THE PERFORMANCE ON SINGLE SERVER BATCH SERVICE MULTIPLE WORKING VACATION QUEUING MODEL WITH COMPULSORY AND EXTENDED REPAIR

590-604

 

 

Lidiya P, K Julia Rose Mary

 

  

 

In this paper, the concept of single-server multiple-working vacations queuing model with compulsory and extended repair is analyzed. In this model, customers arrive at a service facility and form a queue to be served by a single server. The arrival follows the Poisson distribution, and the service follows the exponential distribution. Batches of customers are served under the General Bulk Service Rule. In GBSR, rather than the individual customer arriving in a queue one by one, the customers arrive in groups or batches. Thus, each batch of services contains a minimum of 'a' units and a maximum of 'b' units of customers. In this study, two types of repairs, that is, compulsory and extended repair, are considered. The steady-state equation, the performance of measures for the system, and particular cases of described model are derived. Finally, in the form of tables and graphs, numerical results have been analyzed.  

 

Cite: Lidiya P, K Julia Rose Mary ANALYSIS OF THE PERFORMANCE ON SINGLE SERVER BATCH SERVICE MULTIPLE WORKING VACATION QUEUING MODEL WITH COMPULSORY AND EXTENDED REPAIR. Reliability: Theory & Applications. 2025, June 2(84):  590-604, DOI: https://doi.org/10.24412/1932-2321-2025-284-590-604.


 

 

 

A NEW EXTENSION OF TWO PARAMETER ARADHANA DISTRIBUTION WITH COMPREHENSIVE STATISTICAL PROPERTIES AND APPLICATIONS

605-616

 

 

Rashid A. Ganaie, Manzoor A. Khanday, Prem Lata Gautam, R. Shenbagaraja, T. Vivekanandan

 

  

 

In this study, we introduce a modified extension of standard two parameter Aradhana distribution called as the length biased two parameter Aradhana distribution. The length-biased distributions are a subclass of weighted distributions that adjust the probabilities based on lengths or sizes of observed phenomena, making them suitable for modelling certain practical scenarios. The length biased version is identified as a specific instance of a broader category of weighted distributions, which are widely used in statistical modelling when data collection mechanisms introduce some inherent bias. The distribution is thoroughly examined and analyzed with new structural properties and parameter estimation is performed using a robust and widely used technique of maximum likelihood estimation. The distribution's superiority and effectiveness are evaluated through a comparative analysis involving two real-world datasets. These datasets are used to highlight the practical applicability of the new distribution, demonstrate its flexibility and ability to fit real-world data better than existing models. This comprehensive approach highlights both theoretical advancements and real-world relevance, emphasizing the distribution's versatility and utility.  

 

Cite: Rashid A. Ganaie, Manzoor A. Khanday, Prem Lata Gautam, R. Shenbagaraja, T. Vivekanandan A NEW EXTENSION OF TWO PARAMETER ARADHANA DISTRIBUTION WITH COMPREHENSIVE STATISTICAL PROPERTIES AND APPLICATIONS. Reliability: Theory & Applications. 2025, June 2(84):  605-616, DOI: https://doi.org/10.24412/1932-2321-2025-284-605-616.


 

 

 

LAKIBUL - G FAMILY OF DISTRIBUTIONS: SPECIAL MODELS, PROPERTIES AND APPLICATIONS

617-631

 

 

Iozhar A. Lakibul  

 

 

 

In this study, a new generated family of distributions is introduced, called the Lakhul - G Family of Distributions. The T-X family of distributions is used in the derivation of the proposed class. Three special models of the proposed family are derived, such as the Lakhul - Uniform, Lakhul-Kumaraswamy, and Lakhul-Rayleigh distributions. Some properties of the proposed special models such as moments, mean, variance, moment generating function, survival, and hazard functions are studied. The Maximum likelihood approach is used to estimate the parameters of proposed models. Results show the following: (i) for Lakhul-Uniform distribution, it is found that this proposed probability distribution produces better estimate for electronic dataset as compared with the Cubic Transmuted Uniform distribution; (ii) for Lakhul - Kumaraswamy distribution is found to give a good fit for the COVID-19 dataset compared with the Marshall-Olkin reduce Kies and the Transmuted Kumaraswamy distributions; and (iii) for the Lakhul - Rayleigh distribution, it is observed that this distribution provides a better fit for precipitation dataset as compared with the Exponentialed Transform Inverse Rayleigh and the Exponentialed Inverse Rayleigh distributions.  

 

Cite: Iozhar A. Lakibul   LAKIBUL - G FAMILY OF DISTRIBUTIONS: SPECIAL MODELS, PROPERTIES AND APPLICATIONS. Reliability: Theory & Applications. 2025, June 2(84):  617-631, DOI: https://doi.org/10.24412/1932-2321-2025-284-617-631.


 

 

 

MULTIVARIATE IMPUTATION BY MAHALANOBIS DISTANCE OPTIMIZATION (MIMDO)

632-641

 

 

Geoverr John D. Labita, Altea S. Labita, Bernadette F. Tubo

 

 

 

This paper introduces a new method for missing data imputation based on an optimization approach and is now available as an R package called "mimdo". This method deals with imputing the missing values by computing the values that minimize the Mahalanobis distance between an observation and the overall mean. The effectivity of mimdo was demonstrated in both classification and regression tasks using popular benchmark datasets. From all experiments, it was found out that using mimdo for imputing the missing values in the dataset, on the average, the classification rate is more than 80% and an R-squared of more than 50%. Furthermore, the consistency of the results were validated through simulation studies.  

 

Cite: Geoverr John D. Labita, Altea S. Labita, Bernadette F. Tubo MULTIVARIATE IMPUTATION BY MAHALANOBIS DISTANCE OPTIMIZATION (MIMDO). Reliability: Theory & Applications. 2025, June 2(84):  632-641, DOI: https://doi.org/10.24412/1932-2321-2025-284-632-641.


 

 

 

ENHANCING PREDICTIVE ACCURACY WITH ROBUST LIU AND RANDOM FOREST REGRESSION 

642-647

 

 

Muthukrishnan.R and Karthika Ramakrishnan  

 

 

 

Robust and Random Forest regression procedures are powerful machine learning algorithms that enhance predictive accuracy and handle complex datasets with diverse characteristics. The Robust Liu regression algorithm is designed to address the limitations of conventional regression methods. The robust Liu regression method is considered more reliable in the presence of outliers and multicollinearity. On the other hand, Random Forest is an ensemble learning method that constructs multiple decision trees to improve classification and regression tasks by aggregating predictions from individual trees, thereby mitigating overfitting and increasing robustness to noise. Its ability to capture nonlinear relationships and handle high-dimensional data makes it suitable for many real-world applications. This study compares the performance of Least Squares, Liu, Robust Liu, and Random Forest regression methods using prediction error measures in real and simulated environments. This synergy offers new possibilities for researchers to improve prediction accuracy in the presence of heterogeneous non-normal, multicollinear data and outliers.  

 

Cite: Muthukrishnan.R and Karthika Ramakrishnan   ENHANCING PREDICTIVE ACCURACY WITH ROBUST LIU AND RANDOM FOREST REGRESSION . Reliability: Theory & Applications. 2025, June 2(84):  642-647, DOI: https://doi.org/10.24412/1932-2321-2025-284-642-647.


 

 

 

ELECTROMECHANICAL DEVICES WITH LEVITATION ELEMENTS FOR CONTROL OF NON-ELECTRICAL PARAMETERS

648-654

 

 

G.S. Kerimzade  

 

 

 

The paper presents a mathematical model of electromechanical devices with levitation elements for automatic control of non-electrical parameters, as well as calculation stages for any devices. The mathematical model is based on the equations of levitation, currents, magnetomotive forces, overheating temperature of the windings, and magnetic induction. Numerical values of dimensionless quantities are determined, which can be used as reference data in the development of electromechanical devices with levitation elements. The functional dependences of electromagnetic parameters on the control voltage and stroke of the levitation element are established, and expressions for calculating the force of gravity of the levitation element, lifting force, magnetomotive force and winding overheating temperature are obtained.  

 

Cite: G.S. Kerimzade   ELECTROMECHANICAL DEVICES WITH LEVITATION ELEMENTS FOR CONTROL OF NON-ELECTRICAL PARAMETERS. Reliability: Theory & Applications. 2025, June 2(84):  648-654, DOI: https://doi.org/10.24412/1932-2321-2025-284-648-654.


 

 

 

GEOMETRIC HAZARD-BASED PREVENTIVE MAINTENANCE AND REPLACEMENT (GHBPMAR) MODEL FOR AGING MECHANICALLY REPAIRABLE MACHINES 

655-662

 

 

Nse Udoh, Iniobong Uko, Fredrick Ohaegbunem  

 

 

 

This work aims to develop a geometric hazard-based preventive maintenance model to improve the sustainability of aging mechanically repairable machines particularly in developing countries. The goal is to optimize maintenance and replacement schedules to meet user needs effectively. The model utilizes a geometric process as a hazard rate adjustment factor to account for increasing deterioration rates of machines due to aging and prolong usage and applies same model to a cassava grinding machine across three phases of lifespan: average lifespan, beyond average lifespan, and beyond initial replacement age. The Weibull failure distribution is used to characterize the machine’s increasing failure rate. The result reveals that the machine’s operational time decreases following preventive maintenance, and maintenance costs increase as the machine progresses through many phases of its lifespan. This highlights the model’s effectiveness in managing the cost and timing of maintenance activities. The model’s implementation can significantly impact communities in developing countries by improving the reliability and lifespan of essential machinery like cassava grinding machines and other industrial machines which can lead to stable local economies. This approach helps in managing costs and improving the sustainability of machines, especially in resource-constrained environments over extended lifespan.  

 

Cite: Nse Udoh, Iniobong Uko, Fredrick Ohaegbunem   GEOMETRIC HAZARD-BASED PREVENTIVE MAINTENANCE AND REPLACEMENT (GHBPMAR) MODEL FOR AGING MECHANICALLY REPAIRABLE MACHINES . Reliability: Theory & Applications. 2025, June 2(84):  655-662, DOI: https://doi.org/10.24412/1932-2321-2025-284-655-662.


 

 

 

MOMENTS OF GENERALIZED ORDER STATISTICS FROM DOUBLY TRUNCATED MODIFIED MAKEHAM DISTRIBUTION AND ITS CHARACTERIZATION 

663-676

 

 

Abu Bakar, Zuber Akhter and Mohd Amir

 

 

 

The Makeham distribution has been extensively used in modeling actuarial data and helps as a fundamental life distribution. It describes a mortality failure law in which the hazard rate is composed of two components: a non-aging failure distribution and an aging failure distribution, the latter characterized by an exponentially increasing failure rate. The concept of generalized order statistics (gos), introduced by Kamps in 1995, provides a unified model for combining several models of ordered random variables, including order statistics, record values, progressive type II right-censored order statistics and more. The development of recurrence relations for the moments of gos is an important field of research due to the model’s accessibility and flexibility. These recurrence relations simplify the computation of higher-order moments and establish the associations between moments of different orders. In this article, we have derived the recurrence relations of gos for single and product moments from the doubly truncated modified Makeham distribution and have also reduced these relations for specific ordered random schemes, such as order statistics, k-th record values and sequential order statistics for selected different values of parameters. In the final section, we have presented a characterization theorem based on the recurrence relations of the moments. This theorem has identified the doubly truncated modified Makeham distribution through its moment structure within the gos framework. This shows how important these relationships are for setting this distribution apart from other probability models.  

 

Cite: Abu Bakar, Zuber Akhter and Mohd Amir MOMENTS OF GENERALIZED ORDER STATISTICS FROM DOUBLY TRUNCATED MODIFIED MAKEHAM DISTRIBUTION AND ITS CHARACTERIZATION . Reliability: Theory & Applications. 2025, June 2(84):  663-676, DOI: https://doi.org/10.24412/1932-2321-2025-284-663-676.


 

 

 

A COMPREHENSIVE STUDY OF LIFETIME DISTRIBUTION MODELS FOR AIR CONDITIONING SYSTEMS USING FAILURE TIME DATA

677-684

 

 

S. Mythily, S.C. Premila, P. Manigandan, K. Geetha, D. Pachiyappan and A. Radhika

 

  

 

The purpose of this paper was to fit the model for the air conditioning system with failure time for the normal, gamma, and generalized gamma distributions and to identify the optimal distribution model for estimating the air conditioning system failure time. The performance of the normal, gamma, and generalized gamma distributions on air conditioning system failure data was investigated. To determine the optimal model for calculating the air conditioning system failure time, the secondary data was fitted to the normal, gamma, and generalized gamma distribution models. To evaluate the models performance, the Kolmogorov-Smirnov, and Akaike Information Criterion, were used. The outcomes of the research indicated that the gamma model had the lowest AIC and KS values, measuring 359.108 and 0.47624; the generalized gamma model came in second with AIC and KS values are 359.6058 and 0.32988; and the normal model had the highest AIC and KS values, measuring 3203.729 and 0.4298, respectively. Results show that the gamma model has better flexibility in handling real data over the conventional normal and generalized gamma distribution.  

 

Cite: S. Mythily, S.C. Premila, P. Manigandan, K. Geetha, D. Pachiyappan and A. Radhika A COMPREHENSIVE STUDY OF LIFETIME DISTRIBUTION MODELS FOR AIR CONDITIONING SYSTEMS USING FAILURE TIME DATA. Reliability: Theory & Applications. 2025, June 2(84):  677-684, DOI: https://doi.org/10.24412/1932-2321-2025-284-677-684.


 

 

 

RELIABILITY ANALYSIS OF AAC BLOCK PLANT USING BOOLEAN FUNCTION AND PATH TRACING METHOD 

685-693

 

 

Balram, S.C. Malik, A.D. Yadav and S. Malik  

 

 

 

This study offers a comprehensive reliability analysis of Autoclaved Aerated Concrete (AAC) block plants, employing Boolean function technique and path tracing method. The analysis addresses a non-repairable system comprising five interconnected subsystems arranged in series. Utilizing these mathematical approaches, we derive expressions for reliability and mean time to system failure (MTSF). The study meticulously evaluates system reliability, with a focus on the Weibull distribution, especially the exponential distribution case.  

 

Cite: Balram, S.C. Malik, A.D. Yadav and S. Malik   RELIABILITY ANALYSIS OF AAC BLOCK PLANT USING BOOLEAN FUNCTION AND PATH TRACING METHOD . Reliability: Theory & Applications. 2025, June 2(84):  685-693, DOI: https://doi.org/10.24412/1932-2321-2025-284-685-693.


 

 

 

RELIABILITY- AVAILABILITY - MAINTAINABILITY OF A REPAIRABLE SYSTEM USING MARKOV APPROACH 

694-704

 

 

A. D. Yadav, S.C. Malik, S. Malik and N. Nandal  

 

 

 

This study presents a reliability-availability-maintainability (RAM) analysis of a repairable system consisting of two non-identical units, where one unit operates as the main unit while another unit is in cold standby mode. A Markov approach is applied to develop the system model and transition probability equations are derived using the Chapman-Kolmogorov technique. The system is deemed to have failed only when both units are inoperative.  

 

Cite: A. D. Yadav, S.C. Malik, S. Malik and N. Nandal   RELIABILITY- AVAILABILITY - MAINTAINABILITY OF A REPAIRABLE SYSTEM USING MARKOV APPROACH . Reliability: Theory & Applications. 2025, June 2(84):  694-704, DOI: https://doi.org/10.24412/1932-2321-2025-284-694-704.


 

 

 

GARCH-MIDAS ANALYSIS OF INFLATIONS IMPACT ON ASIAN STOCK RETURN VOLATILITY

705-714

 

 

S. C. Premila, R. Jeena, D. Pachiyappan, B. Ramesh Kumar and S. Kavitha  

 

 

 

This study examines the impact of inflation on stock return volatility in five Asian countries using a GARCH-MIDAS approach with mixed-frequency data (daily stock returns and monthly inflation). Results reveal that higher inflation significantly increases volatility and depresses returns, underscoring inflation's critical role in shaping market dynamics.  

 

Cite: S. C. Premila, R. Jeena, D. Pachiyappan, B. Ramesh Kumar and S. Kavitha   GARCH-MIDAS ANALYSIS OF INFLATIONS IMPACT ON ASIAN STOCK RETURN VOLATILITY. Reliability: Theory & Applications. 2025, June 2(84):  705-714, DOI: https://doi.org/10.24412/1932-2321-2025-284-705-714.


 

 

 

MATHEMATIC SIMLUATION OF SR. CONF. SYSTEM UNDER P. AND C. MAINTENANCE USING PSO

715-726

 

 

Shakuntla Singla, Diksha Mangla, Shilpa Rani  

 

 

 

This paper addressed the performance of a well-maintained two-unit system by calculating reliability metrics like the average duration of system failure and the available time to perform it by counting the effect of the collapse rate and its separation facilities. The goal of this paper is to maximize the overall profit using a nature inspired optimization tool, particle swarm optimization by counting the reliability metrics for the performance of a series framework subjected to the influence of routine upkeep and changing of components.  

 

Cite: Shakuntla Singla, Diksha Mangla, Shilpa Rani   MATHEMATIC SIMLUATION OF SR. CONF. SYSTEM UNDER P. AND C. MAINTENANCE USING PSO. Reliability: Theory & Applications. 2025, June 2(84):  715-726, DOI: https://doi.org/10.24412/1932-2321-2025-284-715-726.


 

 

 

ATTRIBUTE CONTROL CHART APPROACH FOR LIFE TESTING USING EXPONENTIAL-POISSON DISTRIBUTION 

727-735

 

 

Gokila B and Sheik Abdullah A  

 

 

 

This article introduces a novel attribute np control chart for monitoring the median lifetime of products under a hybrid censoring plan, assuming an Exponential-Poisson lifetime distribution. Optimal control chart parameters are derived to minimize deviations from a target Average Run Length (ARL) for an in-control process.  

 

Cite: Gokila B and Sheik Abdullah A   ATTRIBUTE CONTROL CHART APPROACH FOR LIFE TESTING USING EXPONENTIAL-POISSON DISTRIBUTION . Reliability: Theory & Applications. 2025, June 2(84):  727-735, DOI: https://doi.org/10.24412/1932-2321-2025-284-727-735.


 

 

 

ESTIMATE MISSING VALUE OF RANDOMIZED BLOCK DESIGN USING VARIABLE CONTROL CHARTS THROUGH RESPONSE SURFACE METHODOLOGY 

736-749

 

 

Kokkilambigai S and Pachamuthu M  

 

 

 

In this paper, we are introducing the new methods to estimate the missing value using variable control charts such as 3-Sigma and 6-Sigma control charts through Response Surface Methodology (RSM) with the numerical example. RSM can be used to find factor systems that produce a desired maximum, minimum, or optimal response.  

 

Cite: Kokkilambigai S and Pachamuthu M   ESTIMATE MISSING VALUE OF RANDOMIZED BLOCK DESIGN USING VARIABLE CONTROL CHARTS THROUGH RESPONSE SURFACE METHODOLOGY . Reliability: Theory & Applications. 2025, June 2(84):  736-749, DOI: https://doi.org/10.24412/1932-2321-2025-284-736-749.


 

 

 

RELIABILITY AND PROFIT ANALYSIS OF REPAIRABLE EDIBLE OIL PLANT 

750-757

 

 

Ashish Kumar, and Geetanjali Sharma  

 

 

 

This paper described the reliability, availability and profit values of the edible oil plant by using regenerative point graphical technique. Generally, it contains four units such that bleacher (B), deodorizer (D), thermo fluid boiler (C) and pressured filter (A). The whole refinery plant work properly when all units work properly.  

 

Cite: Ashish Kumar, and Geetanjali Sharma   RELIABILITY AND PROFIT ANALYSIS OF REPAIRABLE EDIBLE OIL PLANT . Reliability: Theory & Applications. 2025, June 2(84):  750-757, DOI: https://doi.org/10.24412/1932-2321-2025-284-750-757.


 

 

 

TOUCH AND STEP VOLTAGE HAZARD ANALYSIS 

758-768

 

 

E.S. Safiyev, S.Y. Shikhaliyeva  

 

 

 

This article analyzes the risks associated with electric shock, specifically focusing on the effects of touch and step voltage, which can lead to severe injury or death. The study highlights key factors influencing shock severity, including current magnitude, duration, body resistance, and current path.  

 

Cite: E.S. Safiyev, S.Y. Shikhaliyeva   TOUCH AND STEP VOLTAGE HAZARD ANALYSIS . Reliability: Theory & Applications. 2025, June 2(84):  758-768, DOI: https://doi.org/10.24412/1932-2321-2025-284-758-768.


 

 

 

RELIABILITY ESTIMATION AND PARAMETERS FOR THE LIFESPAN DISTRIBUTION BASED ON FAILURE TIME DATA FOR ELECTRICAL COMPONENTS 

769-775

 

 

K. Geetha, S.N. Manoharan, A. Radhika, S. Mythily, and P. Manigandan  

 

 

 

The objective of the present study is to analyse the failure times of electrical components in order to identify the optimal distribution model for their longevity. Fifteen components failure data were analysed using the Weibull, Lognormal, and Exponential lifespan distribution algorithms.  

 

Cite: K. Geetha, S.N. Manoharan, A. Radhika, S. Mythily, and P. Manigandan   RELIABILITY ESTIMATION AND PARAMETERS FOR THE LIFESPAN DISTRIBUTION BASED ON FAILURE TIME DATA FOR ELECTRICAL COMPONENTS . Reliability: Theory & Applications. 2025, June 2(84):  769-775, DOI: https://doi.org/10.24412/1932-2321-2025-284-769-775.


 

 

 

COMPARATIVE STUDY OF REPAIRABLE JUICE PLANTS USING RPGT 

776-783

 

 

Mohit Yadav, Vandana Swami, Naveen Kumar, Puneet Garg  

 

 

 

In this paper, comparative study of repairable juice plants is analyzed by using regenerative point graphical technique. Generally, juice contains calcium, vitamin, iron, etc. to give the refresh tests. There are multiple steps to store the juice at large levels such as storing, grinding, pasteurization, etc.  

 

Cite: Mohit Yadav, Vandana Swami, Naveen Kumar, Puneet Garg   COMPARATIVE STUDY OF REPAIRABLE JUICE PLANTS USING RPGT . Reliability: Theory & Applications. 2025, June 2(84):  776-783, DOI: https://doi.org/10.24412/1932-2321-2025-284-776-783.


 

 

 

CLUSTERING ELECTRIC POWER SYSTEMS INTO ADEQUACY ASSESSMENT AREAS

784-791

 

 

Dmitry Krupenev, Denis Boyarkin, Nikolay Belyaev  

 

 

 

The article discusses the issue of clustering electric power systems (EPS) into adequacy assessment areas to form equivalent models (EM) of power systems, with such models designed to calculate adequacy metrics. The level of detail of equivalent models is backed by the consideration of two properties of power systems being reliability and economic feasibility.  

 

Cite: Dmitry Krupenev, Denis Boyarkin, Nikolay Belyaev   CLUSTERING ELECTRIC POWER SYSTEMS INTO ADEQUACY ASSESSMENT AREAS. Reliability: Theory & Applications. 2025, June 2(84):  784-791, DOI: https://doi.org/10.24412/1932-2321-2025-284-784-791.


 

 

 

ON CHARACTERIZATION OF 2KTH ORDER WEIGHTED MAXWELL BOLTZMANN DISTRIBUTION

792-802

 

 

Nuzhat Ahad, S.P. Ahmad, J.A. Reshi  

 

 

 

This paper presents the characterization results of the 2Kth order weighted Maxwell Boltzmann distribution (KWMBD). The characterization results are based on the coefficient of variance, a straightforward relationship between two truncated moments, the conditional expectation of a specific function of the random variable, the hazard function, and the reverse hazard function.  

 

Cite: Nuzhat Ahad, S.P. Ahmad, J.A. Reshi   ON CHARACTERIZATION OF 2KTH ORDER WEIGHTED MAXWELL BOLTZMANN DISTRIBUTION. Reliability: Theory & Applications. 2025, June 2(84):  792-802, DOI: https://doi.org/10.24412/1932-2321-2025-284-792-802.


 

 

 

CERTAIN STATIONARY POINT OUTCOMES FOR ASYMPTOTICALLY REGULAR MAPS IN INTERVAL- VALUED N-FUZZY METRIC SPACE 

803-812

 

 

Heera Ahirwar, Kavita Shrivastava, Harshit Khare  

 

 

 

In this study, we introduce interval valued N-fuzzy metric space (IVNFM) and we verify certain popular fixed point results on the structure of interval valued N-fuzzy metric space through asymptotically regular mappings.  

 

Cite: Heera Ahirwar, Kavita Shrivastava, Harshit Khare   CERTAIN STATIONARY POINT OUTCOMES FOR ASYMPTOTICALLY REGULAR MAPS IN INTERVAL- VALUED N-FUZZY METRIC SPACE . Reliability: Theory & Applications. 2025, June 2(84):  803-812, DOI: https://doi.org/10.24412/1932-2321-2025-284-803-812.


 

 

 

OPTIMIZATION OF PERISHABLE INVENTORY IN TWO-WAREHOUSE SYSTEM USING GENETIC ALGORITHMS WITH LOG-GAMMA DECAY AND NONLINEAR DEMAND

813-823

 

 

Garima Sethi, Ajay Singh Yadav, Chaman Singh  

 

 

 

This study presents a detailed inventory framework for managing perishable products distributed across two storage facilities: a capacity-constrained, company-owned primary warehouse and an auxiliary rented warehouse. The model accounts for inventory shortages with partial backlogging, where both the demand rate and backlogging rate are modeled as generalized exponentially decreasing functions of time and selling price.  

 

Cite: Garima Sethi, Ajay Singh Yadav, Chaman Singh   OPTIMIZATION OF PERISHABLE INVENTORY IN TWO-WAREHOUSE SYSTEM USING GENETIC ALGORITHMS WITH LOG-GAMMA DECAY AND NONLINEAR DEMAND. Reliability: Theory & Applications. 2025, June 2(84):  813-823, DOI: https://doi.org/10.24412/1932-2321-2025-284-813-823.


 

 

 

DESIGNING AN ATTRIBUTE CONTROL CHART BASED ON EXPONENTIAL-RAYLEIGH DISTRIBUTION UNDER HYBRID CENSORING

824-833

 

 

T. Kavitha & M. Gunasekaran  

 

 

 

In this paper, we present a new attribute up control chart aimed at monitoring the median lifetime of products within a hybrid censoring scheme, based on the premise that the lifetimes of these products follow an Exponential-Rayleigh distribution.  

 

Cite: T. Kavitha & M. Gunasekaran   DESIGNING AN ATTRIBUTE CONTROL CHART BASED ON EXPONENTIAL-RAYLEIGH DISTRIBUTION UNDER HYBRID CENSORING. Reliability: Theory & Applications. 2025, June 2(84):  824-833, DOI: https://doi.org/10.24412/1932-2321-2025-284-824-833.


 

 

 

A NEW LENGTH BIASED EXPONENTIAL- EXPONENTIAL DISTRIBUTION AND ITS APPLICATIONS TO CANCER DATA

834-843

 

 

Latha J, M Vijayakumar, Shibu D S  

 

 

 

In this paper we propose a new length biased form of the Exponential-Exponential distribution called Length Biased Exponential-Exponential distribution (LBEED) and derive its statistical properties. The statistical properties including the moments, moment generating function, characteristic function, reliability functions and entropy measures are discussed.  

 

Cite: Latha J, M Vijayakumar, Shibu D S   A NEW LENGTH BIASED EXPONENTIAL- EXPONENTIAL DISTRIBUTION AND ITS APPLICATIONS TO CANCER DATA. Reliability: Theory & Applications. 2025, June 2(84):  834-843, DOI: https://doi.org/10.24412/1932-2321-2025-284-834-843.


 

 

 

A NEW GENERALIZATION OF AREA-BIASED XGAMMA DISTRIBUTION WITH PROPERTIES AND ITS APPLICATION TO CANCER DATA

844-856

 

 

Athira D V, P. Pandiyan, and D.S. Shibu  

 

 

 

In this paper, we proposed a new model, "Area Biased Xgamma Distribution", a generalization of the Xgamma distribution. The various distributional properties survival function, hazard function, mean residual life, statistical properties, moments, moment generating function and characteristic function, Bonferroni and Lorenz curve, entropy of the new model were studied.  

 

Cite: Athira D V, P. Pandiyan, and D.S. Shibu   A NEW GENERALIZATION OF AREA-BIASED XGAMMA DISTRIBUTION WITH PROPERTIES AND ITS APPLICATION TO CANCER DATA. Reliability: Theory & Applications. 2025, June 2(84):  844-856, DOI: https://doi.org/10.24412/1932-2321-2025-284-844-856.


 

 

 

APPLICATION OF TYPE-2 FUZZY TOPSIS METHOD FOR ESTIMATING RENEWABLE ENERGY SOURCES

857-867

 

 

Kamala Aliyeva  

 

 

 

This paper offers the integration of spectrum selection optimization algorithms based on the evaluation of the characteristics of various renewable energy options using the TOPSIS fuzzy method.  

 

Cite: Kamala Aliyeva   APPLICATION OF TYPE-2 FUZZY TOPSIS METHOD FOR ESTIMATING RENEWABLE ENERGY SOURCES. Reliability: Theory & Applications. 2025, June 2(84):  857-867, DOI: https://doi.org/10.24412/1932-2321-2025-284-857-867.


 

 

 

A STATISTICAL ANALYSIS OF VARIANCE FOR ONE- WAY CLASSIFICATION USING TRAPEZOIDAL FUZZY TECHNIQUES AND RANKING METHODS

868-881

 

 

Vanitha. R, Pachamuthu. M, Kirthik Väiramariappan. A, Kokkilambigai. S and Sona. S  

 

 

 

This paper presents a statistical analysis of variance for one-way classification using trapezoidal fuzzy techniques and the ranking method, demonstrated through a numerical example.  

 

Cite: Vanitha. R, Pachamuthu. M, Kirthik Väiramariappan. A, Kokkilambigai. S and Sona. S   A STATISTICAL ANALYSIS OF VARIANCE FOR ONE- WAY CLASSIFICATION USING TRAPEZOIDAL FUZZY TECHNIQUES AND RANKING METHODS. Reliability: Theory & Applications. 2025, June 2(84):  868-881, DOI: https://doi.org/10.24412/1932-2321-2025-284-868-881.


 

 

 

ON A CLASS OF INDEFINITE KENMOTSU MANIFOLDS ADMITTING QUARTER-SYMMETRIC METRIC CONNECTION  

882-889

 

 

K. L. Sai Prasad, S. Sunitha Devi  

 

 

 

In this present paper, a class of almost contact metric manifolds equipped with an indefinite metric, termed indefinite Kenmotsu manifolds (known as, $\epsilon$-Kenmotsu), is considered that accepts a connection of quarter-symmetric.  

 

Cite: K. L. Sai Prasad, S. Sunitha Devi   ON A CLASS OF INDEFINITE KENMOTSU MANIFOLDS ADMITTING QUARTER-SYMMETRIC METRIC CONNECTION  . Reliability: Theory & Applications. 2025, June 2(84):  882-889, DOI: https://doi.org/10.24412/1932-2321-2025-284-882-889.


 

 

 

PROPERTIES AND APPLICATION OF ALPHA LOGARITHM TRANSFORMED SINE WEIBULL DISTRIBUTION 

890-902

 

 

A.A. Osi, O.O. Ishaq, B.A. Abdulsalam, Usman Abubakar  

 

 

 

In this research, we introduced a new submodel of the alpha logarithm transform sine-X family of distributions, called the alpha logarithm transform sine-Weibull. We derived its statistical properties, including survival function, hazard function, moments, moment-generating function, and order statistics.  

 

Cite: A.A. Osi, O.O. Ishaq, B.A. Abdulsalam, Usman Abubakar   PROPERTIES AND APPLICATION OF ALPHA LOGARITHM TRANSFORMED SINE WEIBULL DISTRIBUTION . Reliability: Theory & Applications. 2025, June 2(84):  890-902, DOI: https://doi.org/10.24412/1932-2321-2025-284-890-902.


 

 

 

A BATHTUB ADDITIVE FAILURE RATE MODEL FOR ACTUARIAL RELIABILITY

903-917

 

 

M. A. Alhassan, A. Yahaya, O. O. Ishaq, B. Abba, Y. Hussaini, A. Bello  

 

 

 

This paper introduces a lifetime model named Hybrid Weibull-Exponential Power model, based on the later phenomenon vis-a-vis the former approach. The failure rate (FR) of the proposed model displayed suitable compound trends such as increasing-decreasing and various complex forms of bathtub-curve, with and without the lingering useful life period.  

 

Cite: M. A. Alhassan, A. Yahaya, O. O. Ishaq, B. Abba, Y. Hussaini, A. Bello   A BATHTUB ADDITIVE FAILURE RATE MODEL FOR ACTUARIAL RELIABILITY. Reliability: Theory & Applications. 2025, June 2(84):  903-917, DOI: https://doi.org/10.24412/1932-2321-2025-284-903-917.


 

 

 

RESEARCH ON SIGNATURE RECOGNITION METHOD BASED ON DEEP LEARNING TECHNIQUE IN PYTHON LANGUAGE 

918-928

 

 

Phuc Hau Nguyen  

 

 

 

This paper presents a comprehensive study on the construction of a signature recognition system using deep learning with Python. We focus on the preprocessing of signature images, the construction of a CNN model architecture combined with RNN to exploit image features and stroke sequences, and the performance comparison between models.  

 

Cite: Phuc Hau Nguyen   RESEARCH ON SIGNATURE RECOGNITION METHOD BASED ON DEEP LEARNING TECHNIQUE IN PYTHON LANGUAGE . Reliability: Theory & Applications. 2025, June 2(84):  918-928, DOI: https://doi.org/10.24412/1932-2321-2025-284-918-928.


 

 

 

BI STAGE FSSP WITH TRIANGULAR INTUITIONISTIC FUZZY NUMBER AND COMPARISON BETWEEN HEURISTICS

929-943

 

 

Pooja Kaushik, Sonia, Deepak Gupta, Sonia Goel  

 

 

 

This study explores a two-stage FSSP, where parallel machines execute jobs in the both stages. The processing times in the flow shop scheduling are represented by fuzzy numbers in this work. This paper gives comparative study to address the FSSP under an uncertain environment based on triangular intuitionistic fuzzy numbers (T+IFNs).  

 

Cite: Pooja Kaushik, Sonia, Deepak Gupta, Sonia Goel   BI STAGE FSSP WITH TRIANGULAR INTUITIONISTIC FUZZY NUMBER AND COMPARISON BETWEEN HEURISTICS. Reliability: Theory & Applications. 2025, June 2(84):  929-943, DOI: https://doi.org/10.24412/1932-2321-2025-284-929-943.


 

 

 

A NEW DISCRETE ENTROPIC MODEL AND ITS APPLICATION TO CONTINGENCY TABLE INFERENCE

944-956

 

 

Poonam Kumari, Nishi Kumari  

 

 

 

This paper introduces a novel discrete information entropic model and explores its applications in statistical analysis. We have demonstrated the efficacy of this new model by applying it to the inference of contingency tables, a cornerstone of statistical analysis.

 

Cite: Poonam Kumari, Nishi Kumari   A NEW DISCRETE ENTROPIC MODEL AND ITS APPLICATION TO CONTINGENCY TABLE INFERENCE. Reliability: Theory & Applications. 2025, June 2(84):  944-956, DOI: https://doi.org/10.24412/1932-2321-2025-284-944-956.