Seminars are offered to students for education in various disciplines. The seminars may be limited in terms of the maximum number of participants, e.g., to have lively interactions. Due to capacity limitations, those seminars are often offered several times to serve the students’ demands. Still, some seminars are more popular than others and it may not be possible to grant access to all interested students due to capacity limitations. In this paper, a simple, but efficient random selection using key objectives (SEKO) assignment strategy is proposed which achieves the following goals: (i) efficiency by utilizing all available seminar places, (ii) satisfying all students by trying to assign at least one seminar to each student, and (iii) fairness by considering the number of assigned seminars per student. We formulate various theoretical optimization models using integer linear programming (ILP) and compare their solutions to the SEKO assignment based on a real-world data set. The real-world data set is also used as the basis for generating large data sets to investigate the scalability in terms of demand and number of seminars. Furthermore, the first-in first-out (FIFO) assignment, as a typical implementation of fair assignments in practice, is compared to SEKO in terms of utilization and fairness. The results show that the FIFO assignment suffers in real world situations regarding fairness, while the SEKO assignment is close to the optimum and scales regarding computational time in contrast to the ILP.
{"title":"The SEKO assignment. Efficient and fair assignment of students to multiple seminars","authors":"Tobias Hoßfeld _","doi":"10.37190/ord230301","DOIUrl":"https://doi.org/10.37190/ord230301","url":null,"abstract":"Seminars are offered to students for education in various disciplines. The seminars may be limited in terms of the maximum number of participants, e.g., to have lively interactions. Due to capacity limitations, those seminars are often offered several times to serve the students’ demands. Still, some seminars are more popular than others and it may not be possible to grant access to all interested students due to capacity limitations. In this paper, a simple, but efficient random selection using key objectives (SEKO) assignment strategy is proposed which achieves the following goals: (i) efficiency by utilizing all available seminar places, (ii) satisfying all students by trying to assign at least one seminar to each student, and (iii) fairness by considering the number of assigned seminars per student. We formulate various theoretical optimization models using integer linear programming (ILP) and compare their solutions to the SEKO assignment based on a real-world data set. The real-world data set is also used as the basis for generating large data sets to investigate the scalability in terms of demand and number of seminars. Furthermore, the first-in first-out (FIFO) assignment, as a typical implementation of fair assignments in practice, is compared to SEKO in terms of utilization and fairness. The results show that the FIFO assignment suffers in real world situations regarding fairness, while the SEKO assignment is close to the optimum and scales regarding computational time in contrast to the ILP.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135599932","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
TOPSIS is a well-known approach applied to multi-criteria decision-making under certainty (M-DMC). However, recently, some analogies between this domain and scenario-based one-criterion decision-making under uncertainty (1-DMU) have been revealed in the literature. Thus, the similarities aforementioned give the possibility to adjust TOPSIS to another area. The goal of the paper is to create a new method for problems with non-deterministic parameters on the basis of TOPSIS ideas. In the suggested approach criteria weights (declared within TOPSIS) are replaced by subjective chances of occurrence which are estimated for each scenario. The novel method has an advantage over existing classical decision rules designed for 1-criterion decision-making under uncertainty since within this procedure each payoff connected with a given option is compared with the positive and negative-ideal solutions.
{"title":"Scenario planning as a new application area for TOPSIS","authors":"Helena Gaspars-Wieloch","doi":"10.37190/ord230202","DOIUrl":"https://doi.org/10.37190/ord230202","url":null,"abstract":"TOPSIS is a well-known approach applied to multi-criteria decision-making under certainty (M-DMC). However, recently, some analogies between this domain and scenario-based one-criterion decision-making under uncertainty (1-DMU) have been revealed in the literature. Thus, the similarities aforementioned give the possibility to adjust TOPSIS to another area. The goal of the paper is to create a new method for problems with non-deterministic parameters on the basis of TOPSIS ideas. In the suggested approach criteria weights (declared within TOPSIS) are replaced by subjective chances of occurrence which are estimated for each scenario. The novel method has an advantage over existing classical decision rules designed for 1-criterion decision-making under uncertainty since within this procedure each payoff connected with a given option is compared with the positive and negative-ideal solutions.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81947018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Sugapriya, Murugesan Nithya, K. Jeganathan, S. Selvakumar, T. Harikrishnan
This article deals with a Markovian queuing-inventory system (MQIS) under the stochastic modeling technique. The arrival stream of this system is dependent on the present stock level at an instant. Meanwhile, the system focuses on reducing the waiting time of a unit by assuming a queue-dependent service policy (QDSP). The system consists of an infinite waiting hall to receive an arriving unit. The MQIS assumes that no unit of arrival is allowed when the stock level of the system is empty. The discussion of this MQIS runs over the two types of ordering principles named 1) (s, Q) 2) (s, S). According to both ordering principles, the assumed arrival and service patterns have been considered separately and classified as Model-I (M-I) and Model-II (M-II) respectively. The steady state of the system for both M-I and M-II is analysed and resolved under the Neuts matrix-geometric technique. The system performance measures of the system are also computed. The expected cost function of both M-I and M-II are constructed as well. Further, the necessary numerical illustrations are provided and distinguished for M-I and M-II to explore the proposed model. This paper finds the optimum ordering policy to execute the stock-dependent arrival and queue-dependent service strategies.
本文研究了随机建模技术下的马尔可夫排队库存系统。该系统的到货流量取决于当前的库存水平。同时，该系统采用队列依赖服务策略(QDSP)来减少单元的等待时间。该系统由一个无限的等候大厅组成，以接收到达的单位。MQIS假定当系统的库存水平为空时不允许任何到达单位。关于MQIS的讨论涉及两种排序原则，即1)(s, Q) 2) (s, s)。根据这两种排序原则，假定的到达模式和服务模式被分别考虑，并被分类为模型- i (M-I)和模型- ii (M-II)。在Neuts矩阵-几何技术下，对M-I和M-II系统的稳态进行了分析和解析。对系统的性能指标进行了计算。同时构造了M-I和M-II的期望成本函数。此外，还为M-I和M-II提供了必要的数值例证，并对其进行了区分，以探索所提出的模型。本文寻找最优排序策略来执行依赖于库存的到达策略和依赖于队列的服务策略。
{"title":"A comparative analysis of (s, Q) and (s, S) ordering policies in a queueing-inventory system with stock-dependent arrival and queue-dependent service process","authors":"C. Sugapriya, Murugesan Nithya, K. Jeganathan, S. Selvakumar, T. Harikrishnan","doi":"10.37190/ord230207","DOIUrl":"https://doi.org/10.37190/ord230207","url":null,"abstract":"This article deals with a Markovian queuing-inventory system (MQIS) under the stochastic modeling technique. The arrival stream of this system is dependent on the present stock level at an instant. Meanwhile, the system focuses on reducing the waiting time of a unit by assuming a queue-dependent service policy (QDSP). The system consists of an infinite waiting hall to receive an arriving unit. The MQIS assumes that no unit of arrival is allowed when the stock level of the system is empty. The discussion of this MQIS runs over the two types of ordering principles named 1) (s, Q) 2) (s, S). According to both ordering principles, the assumed arrival and service patterns have been considered separately and classified as Model-I (M-I) and Model-II (M-II) respectively. The steady state of the system for both M-I and M-II is analysed and resolved under the Neuts matrix-geometric technique. The system performance measures of the system are also computed. The expected cost function of both M-I and M-II are constructed as well. Further, the necessary numerical illustrations are provided and distinguished for M-I and M-II to explore the proposed model. This paper finds the optimum ordering policy to execute the stock-dependent arrival and queue-dependent service strategies.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86406229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The study aims to develop a decision-making framework by integrating queuing theory and multi-criteria decision-making (MCDM) tools, namely TOPSIS, EDAS, CoCoSo, and TODIM to select a roll-over car washing machine for an oil station. The queue, technical and financial characteristics of the alternatives are added to the decision-making process. The decision matrix includes five criteria and five alternatives. One million weight sets are created randomly, and MCDM techniques are applied to interpret the results statistically. Results indicate that Alternative 3 is statistically superior to the others. The proposed procedure can help decision makers to make decisions when expert knowledge isn’t available, and it can be applied for other purposes by making small changes.
{"title":"Integrating queue theory and multi-criteria decision-making tools for selecting roll-over car washing machine","authors":"Mehmet Ozcalici","doi":"10.37190/ord230206","DOIUrl":"https://doi.org/10.37190/ord230206","url":null,"abstract":"The study aims to develop a decision-making framework by integrating queuing theory and multi-criteria decision-making (MCDM) tools, namely TOPSIS, EDAS, CoCoSo, and TODIM to select a roll-over car washing machine for an oil station. The queue, technical and financial characteristics of the alternatives are added to the decision-making process. The decision matrix includes five criteria and five alternatives. One million weight sets are created randomly, and MCDM techniques are applied to interpret the results statistically. Results indicate that Alternative 3 is statistically superior to the others. The proposed procedure can help decision makers to make decisions when expert knowledge isn’t available, and it can be applied for other purposes by making small changes.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84706244","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study aims to explain the indicators of human resource productivity management in Kerman executive agencies. It is a descriptive, correlational as well as a developmental study purposefully conducted as a survey in the field of human resources. The sample includes 30 experts in the field of management and administration. It was obtained by purposeful sampling method and included 524 employees of the Kerman executive agencies that were gathered by stratified sampling method. Two questionnaires were used by the experts to confirm the validity and reliability of the model and one questionnaire was used to answer the questions. The validity and reliability of all questionnaires were confirmed. AMOS and SPSS statistical software were used for data analysis. The 42 subscales of human resource productivity management are summarized in 5 factors (individual, organizational, complementary organizational, occupational, and extra-organizational). It is an applied developmental study considering the simultaneous identification of factors related to human resource productivity in line with the development indicators and can be used by all executive agencies throughout Iran.
{"title":"Analysis of human resources productivity indicators with structural equations approach. Case study. Kerman executive agencies","authors":"Zohreh Mehtarizadeh","doi":"10.37190/ord230303","DOIUrl":"https://doi.org/10.37190/ord230303","url":null,"abstract":"This study aims to explain the indicators of human resource productivity management in Kerman executive agencies. It is a descriptive, correlational as well as a developmental study purposefully conducted as a survey in the field of human resources. The sample includes 30 experts in the field of management and administration. It was obtained by purposeful sampling method and included 524 employees of the Kerman executive agencies that were gathered by stratified sampling method. Two questionnaires were used by the experts to confirm the validity and reliability of the model and one questionnaire was used to answer the questions. The validity and reliability of all questionnaires were confirmed. AMOS and SPSS statistical software were used for data analysis. The 42 subscales of human resource productivity management are summarized in 5 factors (individual, organizational, complementary organizational, occupational, and extra-organizational). It is an applied developmental study considering the simultaneous identification of factors related to human resource productivity in line with the development indicators and can be used by all executive agencies throughout Iran.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135599316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The main aim of this study is to examine dynamic dependence and proof of contagion during the Covid-2019 pandemic. The empirical data are daily prices from six European indexes. The FTSE, DAX and CAC indexes represent the largest and most developed stock markets in Europe, while the Austrian ATX index represents small developed markets. The WIG and BUX indexes represent emerging European markets. This empirical study, based on the Dynamic Conditional Correlation model, which is applied to different pairs of indexes, aims to convince the reader of the increase in the correlation between the time of the pandemic (after 30 December 2019) and the period before the beginning of the pandemic. For all pairs, the mean value of the conditional correlations in the pre-Covid period was statistically below the values in the Covid period. The results indicate contagion in Europe after the outbreak of the Covid-2019 pandemic.
{"title":"Contagion between selected European indexes during the Covid-19 pandemic","authors":"H. Gurgul, R. Syrek","doi":"10.37190/ord230104","DOIUrl":"https://doi.org/10.37190/ord230104","url":null,"abstract":"The main aim of this study is to examine dynamic dependence and proof of contagion during the Covid-2019 pandemic. The empirical data are daily prices from six European indexes. The FTSE, DAX and CAC indexes represent the largest and most developed stock markets in Europe, while the Austrian ATX index represents small developed markets. The WIG and BUX indexes represent emerging European markets. This empirical study, based on the Dynamic Conditional Correlation model, which is applied to different pairs of indexes, aims to convince the reader of the increase in the correlation between the time of the pandemic (after 30 December 2019) and the period before the beginning of the pandemic. For all pairs, the mean value of the conditional correlations in the pre-Covid period was statistically below the values in the Covid period. The results indicate contagion in Europe after the outbreak of the Covid-2019 pandemic.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79622346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
When we study any queuing system, the performance measures reflect different features of the system. In the classical M/M/1 queuing system, traffic intensity is perhaps the most important performance measure. We propose a fresh and simple estimator for the same and show that it has nice properties. Our approach is frequentist. This approach has the dual advantage of practical usability and familiarity. Our proposed estimator is attractive as it possesses desirable properties. We have shown how our estimator lends itself to testing of hypothesis. Confidence intervals are constructed. Sample size determination is also discussed. A comparison with a few similar estimators is also performed.
{"title":"Frequentist inference on traffic intensity of M/M/1 queuing system","authors":"K. Dutta, Amit Choudhury","doi":"10.37190/ord230102","DOIUrl":"https://doi.org/10.37190/ord230102","url":null,"abstract":"When we study any queuing system, the performance measures reflect different features of the system. In the classical M/M/1 queuing system, traffic intensity is perhaps the most important performance measure. We propose a fresh and simple estimator for the same and show that it has nice properties. Our approach is frequentist. This approach has the dual advantage of practical usability and familiarity. Our proposed estimator is attractive as it possesses desirable properties. We have shown how our estimator lends itself to testing of hypothesis. Confidence intervals are constructed. Sample size determination is also discussed. A comparison with a few similar estimators is also performed.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75244369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
DEMATEL technique is a graphical representation method to deal with complex systems. The final analyzed cause and effect categorization would be fundamentally dependent on the threshold value setting. This research is intended to present some mathematical models for calculating the threshold value in the DEMATEL method. The min(max) operator has been intentionally used for considering three equations to identify the threshold value. Additionally, the proposed mathematical equations are gradually developed to gain more useful data to yield a threshold value as well. Particularly, the expert’s initial scoring for building the primary matrix would also be applied in one equation. Results show eliciting an expert’s opinions regarding the value of a threshold value determination leads to setting relatively high thresholds. But, there would be an equation which takes advantage of more data derived from the total influence matrix T. Moreover, a span of different threshold values is gained by making use of the Hamacher t-conorms operator which especially would cause better complexity management of the final total matrix T based on expert’s opinions. As a contribution to this research, threshold value determination is developed mathematically by making use of the direct data gained by the total matrix T. Besides combining data derived from total matrix T, the initial influence direct matrix given by experts, a simpler aggregating procedure and no need for statistical information compared to special Lenth’s method hints at this research’s novelty as well.
DEMATEL技术是一种处理复杂系统的图形表示方法。最终分析的因果分类将从根本上取决于阈值的设置。本研究旨在提出计算DEMATEL方法中阈值的一些数学模型。最小(最大)运算符被有意用于考虑三个方程来确定阈值。此外，所提出的数学方程逐渐发展，以获得更多有用的数据，以产生一个阈值。特别地，专家为建立主矩阵的初始得分也将应用于一个方程。结果表明，征求专家对阈值确定值的意见会导致设置相对较高的阈值。但是，会有一个方程利用了从总影响矩阵T中导出的更多数据，并且利用Hamacher T - connorm算子获得了不同阈值的跨度，特别是可以根据专家的意见更好地管理最终的总矩阵T的复杂性。作为本研究的贡献之一，利用总矩阵T获得的直接数据，从数学上确定阈值。此外，结合总矩阵T获得的数据，专家给出的初始影响直接矩阵，与特殊的Lenth方法相比，聚合过程更简单，不需要统计信息，也表明了本研究的新颖性。
{"title":"Some equations to identify the threshold value in the DEMATEL method","authors":"Seyed Hossain Ebrahimi","doi":"10.37190/ord230201","DOIUrl":"https://doi.org/10.37190/ord230201","url":null,"abstract":"DEMATEL technique is a graphical representation method to deal with complex systems. The final analyzed cause and effect categorization would be fundamentally dependent on the threshold value setting. This research is intended to present some mathematical models for calculating the threshold value in the DEMATEL method. The min(max) operator has been intentionally used for considering three equations to identify the threshold value. Additionally, the proposed mathematical equations are gradually developed to gain more useful data to yield a threshold value as well. Particularly, the expert’s initial scoring for building the primary matrix would also be applied in one equation. Results show eliciting an expert’s opinions regarding the value of a threshold value determination leads to setting relatively high thresholds. But, there would be an equation which takes advantage of more data derived from the total influence matrix T. Moreover, a span of different threshold values is gained by making use of the Hamacher t-conorms operator which especially would cause better complexity management of the final total matrix T based on expert’s opinions. As a contribution to this research, threshold value determination is developed mathematically by making use of the direct data gained by the total matrix T. Besides combining data derived from total matrix T, the initial influence direct matrix given by experts, a simpler aggregating procedure and no need for statistical information compared to special Lenth’s method hints at this research’s novelty as well.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75978911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Adopting the relationship marketing approach in health institutions and evaluating the weights of its dimensions will benefit the effectiveness of marketing strategies. This study aimed to determine the critical levels of relationship marketing orientation components in private health institutions using the analytical hierarchy process (AHP). In the study, relationship marketing orientation was evaluated according to six criteria in line with the opinions of five experts for employees and 20 people who previously benefited from health services for their customers. As a result, the criterion with the highest priority value was communication with 0.259, and the best health company A. Furthermore, the AHP method results were compared with TOPSIS, EDAS, and CODAS methods. In addition, the Spearman Correlation method was used to determine the correlation between the results.
{"title":"Relationship marketing orientation in healthcare organisations with the AHP. Internal and external customer perspective","authors":"Y. Ersoy, Ali Tehci","doi":"10.37190/ord230103","DOIUrl":"https://doi.org/10.37190/ord230103","url":null,"abstract":"Adopting the relationship marketing approach in health institutions and evaluating the weights of its dimensions will benefit the effectiveness of marketing strategies. This study aimed to determine the critical levels of relationship marketing orientation components in private health institutions using the analytical hierarchy process (AHP). In the study, relationship marketing orientation was evaluated according to six criteria in line with the opinions of five experts for employees and 20 people who previously benefited from health services for their customers. As a result, the criterion with the highest priority value was communication with 0.259, and the best health company A. Furthermore, the AHP method results were compared with TOPSIS, EDAS, and CODAS methods. In addition, the Spearman Correlation method was used to determine the correlation between the results.","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77592635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The paper is aimed to investigate the reliability metrics of a multi-unit fault-tolerant control (FTC) system wherein the units are subject to failure and those are repairable by two heterogeneous servers. Server 1 remains permanently available for essential service of failed units, whereas server 2 goes on vacation and renders service based on the N-policy threshold, which may also provide optional and essential services. Server 1 may break down at a steady rate during its servicing period but immediately gets repaired and resume servicing the failed units. When the working unit fails, the available warm standby unit holds responsibility for the smooth operation of the system. The transition of standby units to operational mode may be unsuccessful with switching failure probability. We develop a Markovian model to obtain the steady-state probabilities. We explore computational and sensitivity analysis of different performance measures for various variability of the parameters
{"title":"Reliability analysis of N-policy vacation based FTC system subject to standby switching failures","authors":"Sudeep Kumar, Ritu Gupta","doi":"10.37190/ord230204","DOIUrl":"https://doi.org/10.37190/ord230204","url":null,"abstract":"The paper is aimed to investigate the reliability metrics of a multi-unit fault-tolerant control (FTC) system wherein the units are subject to failure and those are repairable by two heterogeneous servers. Server 1 remains permanently available for essential service of failed units, whereas server 2 goes on vacation and renders service based on the N-policy threshold, which may also provide optional and essential services. Server 1 may break down at a steady rate during its servicing period but immediately gets repaired and resume servicing the failed units. When the working unit fails, the available warm standby unit holds responsibility for the smooth operation of the system. The transition of standby units to operational mode may be unsuccessful with switching failure probability. We develop a Markovian model to obtain the steady-state probabilities. We explore computational and sensitivity analysis of different performance measures for various variability of the parameters","PeriodicalId":43244,"journal":{"name":"Operations Research and Decisions","volume":null,"pages":null},"PeriodicalIF":0.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84054394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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