Pub Date : 2022-08-10DOI: 10.1080/16843703.2022.2098456
Ming Ha Lee, M. Khoo, A. Haq, Dennis M. L. Wong, Xinying Chew
ABSTRACT In statistical process control, the total number of nonconformities per unit of a process is monitored by using the c chart. In this study, the run length performance of the synthetic c chart with known process parameter (denoted as the KP-Syn-c chart) and the synthetic c chart with estimated process parameter (denoted as the EP-Syn-c chart) are evaluated in terms of the median run length (MRL). The results show that the sensitivity of the MRL-based EP-Syn-c chart is dependent on the number of preliminary samples used in the Phase-I analysis. Furthermore, percentiles of the run length distribution are used to provide a better understanding for the run length performance of the EP-Syn-c chart. The numerical analysis shows that the required minimum number of preliminary samples can be very large for the MRL-based EP-Syn-c chart to perform similar as the KP-Syn-c chart. An optimization procedure is suggested to compute the design parameters of the EP-Syn-c chart by minimizing the out-of-control MRL. Furthermore, the optimal design procedure of the EP-Syn-c chart is also provided through minimizing the out-of-control expected MRL for the unknown process shift size. An example is provided to illustrate the design and implementation of the MRL-based EP-Syn-c chart.
{"title":"Synthetic c charts with known and estimated process parameters based on median run length and expected median run length","authors":"Ming Ha Lee, M. Khoo, A. Haq, Dennis M. L. Wong, Xinying Chew","doi":"10.1080/16843703.2022.2098456","DOIUrl":"https://doi.org/10.1080/16843703.2022.2098456","url":null,"abstract":"ABSTRACT In statistical process control, the total number of nonconformities per unit of a process is monitored by using the c chart. In this study, the run length performance of the synthetic c chart with known process parameter (denoted as the KP-Syn-c chart) and the synthetic c chart with estimated process parameter (denoted as the EP-Syn-c chart) are evaluated in terms of the median run length (MRL). The results show that the sensitivity of the MRL-based EP-Syn-c chart is dependent on the number of preliminary samples used in the Phase-I analysis. Furthermore, percentiles of the run length distribution are used to provide a better understanding for the run length performance of the EP-Syn-c chart. The numerical analysis shows that the required minimum number of preliminary samples can be very large for the MRL-based EP-Syn-c chart to perform similar as the KP-Syn-c chart. An optimization procedure is suggested to compute the design parameters of the EP-Syn-c chart by minimizing the out-of-control MRL. Furthermore, the optimal design procedure of the EP-Syn-c chart is also provided through minimizing the out-of-control expected MRL for the unknown process shift size. An example is provided to illustrate the design and implementation of the MRL-based EP-Syn-c chart.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"168 - 183"},"PeriodicalIF":2.8,"publicationDate":"2022-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47170207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-09DOI: 10.1080/16843703.2022.2088934
Zhen Wang, Cheryl Yang, Yiqiang Q. Zhao
ABSTRACT We study a passenger-taxi double-ended queue with negative passengers and two-point matching time. The system considered in this paper is different from those studied in the existing literature, which fully explores the matching time between passengers and taxis, and the taxi capacity of the system. The objective is to get the equilibrium joining strategy and the socially optimal strategy under two information levels. For the practical consideration of the airport terminal scenario, two different information levels are investigated. The theoretical results show that the passenger utility function in the partially observable case is monotonic. For the complex form of social welfare function of the partially observable case, we use a split derivation. The equilibrium strategy and socially optimal strategy of the observable case are threshold-type. Furthermore, some representative numerical scenarios are used to visualize the theoretical results. The numerical scenarios illustrate the influence of parameters on the equilibrium strategy and socially optimal strategy under two information levels. Finally, the optimal social welfare for the two information levels with the same parameters is compared.
{"title":"Equilibrium and socially optimal strategies of a double-sided queueing system with two-mass point matching time","authors":"Zhen Wang, Cheryl Yang, Yiqiang Q. Zhao","doi":"10.1080/16843703.2022.2088934","DOIUrl":"https://doi.org/10.1080/16843703.2022.2088934","url":null,"abstract":"ABSTRACT We study a passenger-taxi double-ended queue with negative passengers and two-point matching time. The system considered in this paper is different from those studied in the existing literature, which fully explores the matching time between passengers and taxis, and the taxi capacity of the system. The objective is to get the equilibrium joining strategy and the socially optimal strategy under two information levels. For the practical consideration of the airport terminal scenario, two different information levels are investigated. The theoretical results show that the passenger utility function in the partially observable case is monotonic. For the complex form of social welfare function of the partially observable case, we use a split derivation. The equilibrium strategy and socially optimal strategy of the observable case are threshold-type. Furthermore, some representative numerical scenarios are used to visualize the theoretical results. The numerical scenarios illustrate the influence of parameters on the equilibrium strategy and socially optimal strategy under two information levels. Finally, the optimal social welfare for the two information levels with the same parameters is compared.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"89 - 112"},"PeriodicalIF":2.8,"publicationDate":"2022-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47056009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-05DOI: 10.1080/16843703.2022.2096198
Edgard M. Maboudou-Tchao, Charles W. Harrison, Sumen Sen
ABSTRACT Recently statistical process control (SPC) started incorporating advanced tools based on statistical learning for process monitoring due to the increasing availability of large and complex data sets. This phenomenon has generated new problems such as monitoring high-dimensional processes. Two well-known techniques used for this purpose are penalized likelihood and support vector-based process control charts. We investigate the support vector data description (SVDD), an effective method used in multivariate statistical process control (MSPC). Next, a least squares analogue to the SVDD, called LS-SVDD, is investigated. LS-SVDD is formulated using equality constraints in the underlying optimization problem which facilitates a fast, closed-form solution. Variable selection charts are penalized likelihood charts that use diagnosis methodologies for the identification of changed variables. Other penalized likelihood methods using Tikhonov regularization were proposed recently. This approach shrinks all process mean estimates towards zero rather than selecting variables, and it yields a closed-form solution of the monitoring statistic. In this article, we compare penalized methods and support vector methods for Shewhart-type and accumulative-type control charts.
{"title":"A comparison study of penalized likelihood via regularization and support vector-based control charts","authors":"Edgard M. Maboudou-Tchao, Charles W. Harrison, Sumen Sen","doi":"10.1080/16843703.2022.2096198","DOIUrl":"https://doi.org/10.1080/16843703.2022.2096198","url":null,"abstract":"ABSTRACT Recently statistical process control (SPC) started incorporating advanced tools based on statistical learning for process monitoring due to the increasing availability of large and complex data sets. This phenomenon has generated new problems such as monitoring high-dimensional processes. Two well-known techniques used for this purpose are penalized likelihood and support vector-based process control charts. We investigate the support vector data description (SVDD), an effective method used in multivariate statistical process control (MSPC). Next, a least squares analogue to the SVDD, called LS-SVDD, is investigated. LS-SVDD is formulated using equality constraints in the underlying optimization problem which facilitates a fast, closed-form solution. Variable selection charts are penalized likelihood charts that use diagnosis methodologies for the identification of changed variables. Other penalized likelihood methods using Tikhonov regularization were proposed recently. This approach shrinks all process mean estimates towards zero rather than selecting variables, and it yields a closed-form solution of the monitoring statistic. In this article, we compare penalized methods and support vector methods for Shewhart-type and accumulative-type control charts.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"147 - 167"},"PeriodicalIF":2.8,"publicationDate":"2022-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44605434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-03DOI: 10.1080/16843703.2022.2093817
Lirong Cui, Fengming Kang, Jingyuan Shen
ABSTRACT Maintenance planning and optimizations are very important issues in both theory and practice. In this paper, Hawkes processes, a tool for description of self-excited failure effects, are used to model the failure processes of single-unit systems under the assumption of neglected repair times. For such degraded single-unit systems, some maintenance planning estimations such as the distribution, mean and variance of failures or repairs by time , reliability, mean cost of maintenance, mean and variance of system lifetime are presented under the maximal entropy assumption on repair effects. Meanwhile, two optimization problems are developed by considering the lifetime mean of the single-unit system and total maintenance cost as objective functions and constraints alternatively. We have proved that both optimization problems can reduce to two simplified optimal cases, respectively, and their optimal policies are increasing stepwise sequences of increasing rates of failure rates, which greatly reduce the scope of optimal solutions. The relationships between the estimations and the optimizations are discussed. Furthermore, the detailed optimal maintenance policies for a special case are given as well including an algorithm.
{"title":"Maintenance planning estimations and policies optimization for single-unit systems using Hawkes processes","authors":"Lirong Cui, Fengming Kang, Jingyuan Shen","doi":"10.1080/16843703.2022.2093817","DOIUrl":"https://doi.org/10.1080/16843703.2022.2093817","url":null,"abstract":"ABSTRACT Maintenance planning and optimizations are very important issues in both theory and practice. In this paper, Hawkes processes, a tool for description of self-excited failure effects, are used to model the failure processes of single-unit systems under the assumption of neglected repair times. For such degraded single-unit systems, some maintenance planning estimations such as the distribution, mean and variance of failures or repairs by time , reliability, mean cost of maintenance, mean and variance of system lifetime are presented under the maximal entropy assumption on repair effects. Meanwhile, two optimization problems are developed by considering the lifetime mean of the single-unit system and total maintenance cost as objective functions and constraints alternatively. We have proved that both optimization problems can reduce to two simplified optimal cases, respectively, and their optimal policies are increasing stepwise sequences of increasing rates of failure rates, which greatly reduce the scope of optimal solutions. The relationships between the estimations and the optimizations are discussed. Furthermore, the detailed optimal maintenance policies for a special case are given as well including an algorithm.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"211 - 235"},"PeriodicalIF":2.8,"publicationDate":"2022-08-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42436208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-02DOI: 10.1080/16843703.2022.2101338
Wei Sun, Zhiyuan Zhang, Shiyong Li
ABSTRACT This paper studies and compares customer balking behavior in some single-server observable queues with N policies and geometric abandonments. We focus on two types of N policies: the classic one and the modified one. Under the classic N policy, the server begins to take a vacation period as soon as the system becomes empty until there are N customers in the queue. On the other hand, under the modified N policy, the server takes multiple vacations until at least N customers are waiting in the queue when a vacation time ends. Abandonment opportunities occur during a whole vacation period, and customers decide independently and sequentially whether to renege. Comparing the two types of N policies, we realize that the residual time of the server's last vacation under the modified N policy indeed inhibits customers joining, whereas it may be more economic in practice if we take the whole system cost into consideration. As for the optimal N, under which the server is free of compensation, we observe that he should choose the modified N policy when the abandonment probability is much close to 1. Otherwise, he should choose the classic N policy.
{"title":"Comparisons of customer balking behavior in observable queues with N policies and geometric abandonments","authors":"Wei Sun, Zhiyuan Zhang, Shiyong Li","doi":"10.1080/16843703.2022.2101338","DOIUrl":"https://doi.org/10.1080/16843703.2022.2101338","url":null,"abstract":"ABSTRACT This paper studies and compares customer balking behavior in some single-server observable queues with N policies and geometric abandonments. We focus on two types of N policies: the classic one and the modified one. Under the classic N policy, the server begins to take a vacation period as soon as the system becomes empty until there are N customers in the queue. On the other hand, under the modified N policy, the server takes multiple vacations until at least N customers are waiting in the queue when a vacation time ends. Abandonment opportunities occur during a whole vacation period, and customers decide independently and sequentially whether to renege. Comparing the two types of N policies, we realize that the residual time of the server's last vacation under the modified N policy indeed inhibits customers joining, whereas it may be more economic in practice if we take the whole system cost into consideration. As for the optimal N, under which the server is free of compensation, we observe that he should choose the modified N policy when the abandonment probability is much close to 1. Otherwise, he should choose the classic N policy.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"307 - 333"},"PeriodicalIF":2.8,"publicationDate":"2022-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47117505","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-22DOI: 10.1080/16843703.2022.2092954
George C. Mytalas, M. Zazanis
ABSTRACT We analyze an M/G/1 system with batch Poisson arrivals and instantaneous Bernoulli feedback, operating under a Multiple Vacation Policy. The system is subject to disasters that occur according to an independent Poisson process and are followed by (random) repair periods with general distribution. The analysis is carried out using the supplementary variable method. The Laplace transform of the time between two consecutive disasters is obtained and the existence of the stationary regime for the system is shown. Besides obtaining the stationary distribution for the number of customers in the system, we use the information regarding the rates of occurrence of various events provided by the supplementary variable solution to obtain a great variety of additional results. These include the Laplace transform of the busy period distribution and the probability that a customer completes service. We indicate areas of application of our model to real-life systems, in particular in Vehicle ad hoc Networks (VANETs), and we use the analytic results obtained to optimize such a system under a Quality of Service constraint. Finally, we analyze a variant of the system subject to disasters even when the server is not busy.
{"title":"Performance analysis for Bernoulli feedback queues subject to disasters: a system with batch Poisson arrivals under a multiple vacation policy","authors":"George C. Mytalas, M. Zazanis","doi":"10.1080/16843703.2022.2092954","DOIUrl":"https://doi.org/10.1080/16843703.2022.2092954","url":null,"abstract":"ABSTRACT We analyze an M/G/1 system with batch Poisson arrivals and instantaneous Bernoulli feedback, operating under a Multiple Vacation Policy. The system is subject to disasters that occur according to an independent Poisson process and are followed by (random) repair periods with general distribution. The analysis is carried out using the supplementary variable method. The Laplace transform of the time between two consecutive disasters is obtained and the existence of the stationary regime for the system is shown. Besides obtaining the stationary distribution for the number of customers in the system, we use the information regarding the rates of occurrence of various events provided by the supplementary variable solution to obtain a great variety of additional results. These include the Laplace transform of the busy period distribution and the probability that a customer completes service. We indicate areas of application of our model to real-life systems, in particular in Vehicle ad hoc Networks (VANETs), and we use the analytic results obtained to optimize such a system under a Quality of Service constraint. Finally, we analyze a variant of the system subject to disasters even when the server is not busy.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"113 - 146"},"PeriodicalIF":2.8,"publicationDate":"2022-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46617226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-07-03DOI: 10.1080/16843703.2022.2093565
Hamzeh Soltanali, M. Khojastehpour, José Torres Farinha
ABSTRACT In food processing systems, it is necessary to evaluate the risk process and reliability in order to prevent unexpected events and control functional safety through well-planned maintenance. This study examines risk and reliability models and develops their theories using a novel framework based on failure behavior trends. The proposed framework was implemented in edible oil industries, specifically purification processes, and consists of three steps: first, identifying potential failures using risk-based approaches such as Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA); second, adapting a statistical structure consisting of homogenization survey and validity of identity and independence; and finally, estimating the failure rate and reliability to find the suitable maintenance intervals. The findings revealed that the proposed framework is capable of identifying critical equipment with high failure rates as the most important bottlenecks in edible oil processing lines, allowing maintenance plans to be carried out based on the various levels of reliability. Furthermore, opportunistic maintenance intervals were suggested due to the series configuration of equipment in such a process. As a result, the findings of this study may be useful in improving process safety and availability in the food processing industry.
{"title":"An improved risk and reliability framework-based maintenance planning for food processing systems","authors":"Hamzeh Soltanali, M. Khojastehpour, José Torres Farinha","doi":"10.1080/16843703.2022.2093565","DOIUrl":"https://doi.org/10.1080/16843703.2022.2093565","url":null,"abstract":"ABSTRACT In food processing systems, it is necessary to evaluate the risk process and reliability in order to prevent unexpected events and control functional safety through well-planned maintenance. This study examines risk and reliability models and develops their theories using a novel framework based on failure behavior trends. The proposed framework was implemented in edible oil industries, specifically purification processes, and consists of three steps: first, identifying potential failures using risk-based approaches such as Failure Mode and Effect Analysis (FMEA) and Fault Tree Analysis (FTA); second, adapting a statistical structure consisting of homogenization survey and validity of identity and independence; and finally, estimating the failure rate and reliability to find the suitable maintenance intervals. The findings revealed that the proposed framework is capable of identifying critical equipment with high failure rates as the most important bottlenecks in edible oil processing lines, allowing maintenance plans to be carried out based on the various levels of reliability. Furthermore, opportunistic maintenance intervals were suggested due to the series configuration of equipment in such a process. As a result, the findings of this study may be useful in improving process safety and availability in the food processing industry.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"256 - 278"},"PeriodicalIF":2.8,"publicationDate":"2022-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45503574","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.1080/16843703.2022.2084281
Z. Jalilibal, Mohammad Hassan Ahmadi Karavigh, A. Amiri, M. Khoo
ABSTRACT Different control charts are developed for monitoring various types of quality characteristics in the area of Statistical Process Monitoring (SPM). Moreover, new techniques are proposed to improve the performances of the suggested control charts. One of the popular techniques for this purpose is run rules. These rules increase the sensitivity of control charts in detecting different shift sizes, especially small and medium shifts. In this paper, a content analysis (based on 100 papers in this area from 1955 to 2020) is conducted to (i) classify the articles that employed run rules in SPM, (ii) recognize the research gaps and (iii) provide guidance to motivate future research in this area.
{"title":"Run rules schemes for statistical process monitoring: a literature review","authors":"Z. Jalilibal, Mohammad Hassan Ahmadi Karavigh, A. Amiri, M. Khoo","doi":"10.1080/16843703.2022.2084281","DOIUrl":"https://doi.org/10.1080/16843703.2022.2084281","url":null,"abstract":"ABSTRACT Different control charts are developed for monitoring various types of quality characteristics in the area of Statistical Process Monitoring (SPM). Moreover, new techniques are proposed to improve the performances of the suggested control charts. One of the popular techniques for this purpose is run rules. These rules increase the sensitivity of control charts in detecting different shift sizes, especially small and medium shifts. In this paper, a content analysis (based on 100 papers in this area from 1955 to 2020) is conducted to (i) classify the articles that employed run rules in SPM, (ii) recognize the research gaps and (iii) provide guidance to motivate future research in this area.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"21 - 52"},"PeriodicalIF":2.8,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41929245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-15DOI: 10.1080/16843703.2022.2079062
He-Yau Kang, Amy H. I. Lee
ABSTRACT Assembly lines are often indispensable in factories, and a good assembly-line balancing model is very important for manufacturers to maximize their profit using limited resources in a competitive environment. To maintain a productive assembly line, multiple objectives with different importance must be considered at the same time. In this paper, a two-sided assembly-line balancing problem (TALBP) with multiple objectives is examined. A fuzzy multi-objective linear programming-weighted model (FMOLP-W) for solving the TALBP is constructed first with the consideration of the importance weights of the line balancing performance factors, including minimizing the number of workstations, minimizing cycle time, maximizing line efficiency, minimizing smoothness index and minimizing workstation idle time. An evolutionary genetic algorithm (GA) is proposed next to tackle large-scale problems when the problems are too complex to be solved by the FMOLP-W.
{"title":"An evolutionary genetic algorithm for a multi-objective two-sided assembly line balancing problem: a case study of automotive manufacturing operations","authors":"He-Yau Kang, Amy H. I. Lee","doi":"10.1080/16843703.2022.2079062","DOIUrl":"https://doi.org/10.1080/16843703.2022.2079062","url":null,"abstract":"ABSTRACT Assembly lines are often indispensable in factories, and a good assembly-line balancing model is very important for manufacturers to maximize their profit using limited resources in a competitive environment. To maintain a productive assembly line, multiple objectives with different importance must be considered at the same time. In this paper, a two-sided assembly-line balancing problem (TALBP) with multiple objectives is examined. A fuzzy multi-objective linear programming-weighted model (FMOLP-W) for solving the TALBP is constructed first with the consideration of the importance weights of the line balancing performance factors, including minimizing the number of workstations, minimizing cycle time, maximizing line efficiency, minimizing smoothness index and minimizing workstation idle time. An evolutionary genetic algorithm (GA) is proposed next to tackle large-scale problems when the problems are too complex to be solved by the FMOLP-W.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"20 1","pages":"66 - 88"},"PeriodicalIF":2.8,"publicationDate":"2022-06-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44397041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-13DOI: 10.1080/16843703.2022.2049507
Amulya Kumar Mahto, Chandrakant Lodhi, Y. Tripathi, Liang Wang
ABSTRACT We study a competing risks model under the assumption that latent failure times follow family of Lomax distributions. We obtain various inferences for model parameters when causes of failure are partially known and lifetime data are observed using a generalized progressive hybrid censoring scheme. The existence and uniqueness properties of maximum likelihood estimators of unknown parameters are established. Bayes estimators and associated credible intervals are also obtained. In addition, various inferences for unknown parameters are derived under order-restricted shape parameters of Lomax distributions. Finally, a simulation study is conducted to evaluate the performance of the proposed estimates. A real data set is also analysed for illustration purposes.
{"title":"On partially observed competing risk model under generalized progressive hybrid censoring for Lomax distribution","authors":"Amulya Kumar Mahto, Chandrakant Lodhi, Y. Tripathi, Liang Wang","doi":"10.1080/16843703.2022.2049507","DOIUrl":"https://doi.org/10.1080/16843703.2022.2049507","url":null,"abstract":"ABSTRACT We study a competing risks model under the assumption that latent failure times follow family of Lomax distributions. We obtain various inferences for model parameters when causes of failure are partially known and lifetime data are observed using a generalized progressive hybrid censoring scheme. The existence and uniqueness properties of maximum likelihood estimators of unknown parameters are established. Bayes estimators and associated credible intervals are also obtained. In addition, various inferences for unknown parameters are derived under order-restricted shape parameters of Lomax distributions. Finally, a simulation study is conducted to evaluate the performance of the proposed estimates. A real data set is also analysed for illustration purposes.","PeriodicalId":49133,"journal":{"name":"Quality Technology and Quantitative Management","volume":"19 1","pages":"562 - 586"},"PeriodicalIF":2.8,"publicationDate":"2022-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44947241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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