Pub Date : 2021-09-21DOI: 10.1108/ijqrm-12-2020-0396
J. Sordan, P. Oprime, M. Pimenta, Sérgio Luis da Silva, M. González
PurposeThis paper aims to develop a conceptual framework of the implementation of the contact points (CPs) between Lean Six Sigma practices and Industry 4.0 technologies.Design/methodology/approachA systematic literature review was carried out based on two samples. A first sample containing 78 articles was analyzed through bibliometric indicators. After that, a second sample of 33 articles was analyzed in-depth according to research questions.FindingsThe conceptual framework involves 13 CPs between Lean Six Sigma (LSS) practices and I4.0 technologies (what), going through the technical requirements needed (how), categorized as information technology (IT), automation and competence requirements, to finally present the main results reported in the literature (why).Research limitations/implicationsThis paper presents an innovative perspective of interactions between digital technologies and LSS practices, expanding knowledge about Digital LSS. Such perspective gives emphasis to the importance of technical requirements, such as communication and connectivity protocols, network topology, machine-to-machine communication (M2M), human–machine interfaces (HMI), as well as analytical and digital skills.Practical implicationsThe managerial implications regarding the digitalization of LSS practices address the investments required for the acquisition and maintenance of cyber-physical systems (CPS). Moreover, there is a need for the development of skills so that operators can successfully use the new technologies in a context of continuous improvement.Originality/valueThis paper presents a conceptual framework covering 13 CPs between LSS practices and Industry 4.0 technologies, the technical requirements and the expected results. It is hoped that this framework can assist future research and operational excellence projects towards digitalization.
{"title":"Contact points between Lean Six Sigma and Industry 4.0: a systematic review and conceptual framework","authors":"J. Sordan, P. Oprime, M. Pimenta, Sérgio Luis da Silva, M. González","doi":"10.1108/ijqrm-12-2020-0396","DOIUrl":"https://doi.org/10.1108/ijqrm-12-2020-0396","url":null,"abstract":"PurposeThis paper aims to develop a conceptual framework of the implementation of the contact points (CPs) between Lean Six Sigma practices and Industry 4.0 technologies.Design/methodology/approachA systematic literature review was carried out based on two samples. A first sample containing 78 articles was analyzed through bibliometric indicators. After that, a second sample of 33 articles was analyzed in-depth according to research questions.FindingsThe conceptual framework involves 13 CPs between Lean Six Sigma (LSS) practices and I4.0 technologies (what), going through the technical requirements needed (how), categorized as information technology (IT), automation and competence requirements, to finally present the main results reported in the literature (why).Research limitations/implicationsThis paper presents an innovative perspective of interactions between digital technologies and LSS practices, expanding knowledge about Digital LSS. Such perspective gives emphasis to the importance of technical requirements, such as communication and connectivity protocols, network topology, machine-to-machine communication (M2M), human–machine interfaces (HMI), as well as analytical and digital skills.Practical implicationsThe managerial implications regarding the digitalization of LSS practices address the investments required for the acquisition and maintenance of cyber-physical systems (CPS). Moreover, there is a need for the development of skills so that operators can successfully use the new technologies in a context of continuous improvement.Originality/valueThis paper presents a conceptual framework covering 13 CPs between LSS practices and Industry 4.0 technologies, the technical requirements and the expected results. It is hoped that this framework can assist future research and operational excellence projects towards digitalization.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41666614","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}
Pub Date : 2021-09-20DOI: 10.1108/ijqrm-06-2021-0166
Marwa K. H. Hassan
PurposeDistribution. The purpose of this study is to obtain the modified maximum likelihood estimator of stress–strength model using the ranked set sampling, to obtain the asymptotic and bootstrap confidence interval of P[Y < X], to compare the performance of author’s estimates with the estimates under simple random sampling and to apply author’s estimates on head and neck cancer.Design/methodology/approachThe maximum likelihood estimator of R = P[Y < X], where X and Y are two independent inverse Weibull random variables common shape parameter that affect the shape of the distribution, and different scale parameters that have an effect on the distribution dispersion are given under ranked set sampling. Together with the asymptotic and bootstrap confidence interval, Monte Carlo simulation shows that this estimator performs better than the estimator under simple random sampling. Also, the asymptotic and bootstrap confidence interval under ranked set sampling is better than these interval estimators under simple random sampling. The application to head and neck cancer disease data shows that the estimator of R = P[Y < X] that shows the treatment with radiotherapy is more efficient than the treatment with a combined radiotherapy and chemotherapy under ranked set sampling that is better than these estimators under simple random sampling.FindingsThe ranked set sampling is more effective than the simple random sampling for the inference of stress-strength model based on inverse Weibull distribution.Originality/valueThis study sheds light on the author’s estimates on head and neck cancer.
目的分发。本研究的目的是使用排序集抽样获得应力-强度模型的修正最大似然估计量，获得P[Y
{"title":"Ranked set sampling on estimation of P[Y","authors":"Marwa K. H. Hassan","doi":"10.1108/ijqrm-06-2021-0166","DOIUrl":"https://doi.org/10.1108/ijqrm-06-2021-0166","url":null,"abstract":"PurposeDistribution. The purpose of this study is to obtain the modified maximum likelihood estimator of stress–strength model using the ranked set sampling, to obtain the asymptotic and bootstrap confidence interval of P[Y < X], to compare the performance of author’s estimates with the estimates under simple random sampling and to apply author’s estimates on head and neck cancer.Design/methodology/approachThe maximum likelihood estimator of R = P[Y < X], where X and Y are two independent inverse Weibull random variables common shape parameter that affect the shape of the distribution, and different scale parameters that have an effect on the distribution dispersion are given under ranked set sampling. Together with the asymptotic and bootstrap confidence interval, Monte Carlo simulation shows that this estimator performs better than the estimator under simple random sampling. Also, the asymptotic and bootstrap confidence interval under ranked set sampling is better than these interval estimators under simple random sampling. The application to head and neck cancer disease data shows that the estimator of R = P[Y < X] that shows the treatment with radiotherapy is more efficient than the treatment with a combined radiotherapy and chemotherapy under ranked set sampling that is better than these estimators under simple random sampling.FindingsThe ranked set sampling is more effective than the simple random sampling for the inference of stress-strength model based on inverse Weibull distribution.Originality/valueThis study sheds light on the author’s estimates on head and neck cancer.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43701594","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}
Pub Date : 2021-09-20DOI: 10.1108/ijqrm-12-2020-0407
Shweta Agarwal, S.B. Singh
PurposeThe purpose of the paper is to analyze reliability characteristics of batch service queuing system with a single server model that envisages Poisson input process and exponential service times under first come, first served (FCFS) queue discipline.Design/methodology/approachWith the help of renewal theory and stochastic processes, a model has been designed to discuss the reliability and its characteristics.FindingsThe instantaneous and steady-state availability along with the maintenance model of the systems subject to generalized M/Mb/1 queuing model is derived, and a few particular cases for availability are obtained as well. For supporting the developed model, a case study on electrical distribution system (EDS) has been illustrated, which also includes a comparison for the system subject to M/Mb/1 queuing model and the system without any queue (delay).Originality/valueIt is a quite realistic model that may aid to remove congestion in the system while repairing.
{"title":"Availability and maintenance modeling of a batch service queuing system","authors":"Shweta Agarwal, S.B. Singh","doi":"10.1108/ijqrm-12-2020-0407","DOIUrl":"https://doi.org/10.1108/ijqrm-12-2020-0407","url":null,"abstract":"PurposeThe purpose of the paper is to analyze reliability characteristics of batch service queuing system with a single server model that envisages Poisson input process and exponential service times under first come, first served (FCFS) queue discipline.Design/methodology/approachWith the help of renewal theory and stochastic processes, a model has been designed to discuss the reliability and its characteristics.FindingsThe instantaneous and steady-state availability along with the maintenance model of the systems subject to generalized M/Mb/1 queuing model is derived, and a few particular cases for availability are obtained as well. For supporting the developed model, a case study on electrical distribution system (EDS) has been illustrated, which also includes a comparison for the system subject to M/Mb/1 queuing model and the system without any queue (delay).Originality/valueIt is a quite realistic model that may aid to remove congestion in the system while repairing.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48472521","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}
Pub Date : 2021-09-15DOI: 10.1108/ijqrm-06-2021-0187
H. Pant, S.B. Singh
PurposeIn certain environments, the system may not fail completely, but undergoes degradation, and the system productivity might decrease. Meanwhile, at the same time, the system may be vulnerable to shocks. A single-unit system prone to degradation and shocks is proposed in this study, and emphasis is placed upon determining its availability and cost rate.Design/methodology/approachThe considered single-unit system is expected to have three states, namely, normal, degraded and failed. As the system enters the degraded state, it is said to be partially failed. The degraded state incurs higher degradation than the normal state and is more prone to shocks. Inspections are used to determine the state and failure type of the system. Inspections are predetermined to be carried out sequentially at time I, I+aI, I+aI+a2I,… where 0 < a ≤ 1, until the detection of degradation/failure. Perfect repairs are conducted instantly on spotting the partial/complete failure. Two cases have been considered of repair taking constant times and random times.FindingsExplicit results on the reliability, availability (both point and limiting availability) and long-run average cost rate (LRACR) of a sequentially inspected single-unit system prone to degradation and shocks under constant and random repair times are given. Numerical example of an oil pipeline system is taken to clarify the acquired results.Originality/valueA sequentially inspected single-unit system prone to degradation and shock is studied unlike done previously.
{"title":"Modeling a sequentially inspected system prone to degradation and shocks","authors":"H. Pant, S.B. Singh","doi":"10.1108/ijqrm-06-2021-0187","DOIUrl":"https://doi.org/10.1108/ijqrm-06-2021-0187","url":null,"abstract":"PurposeIn certain environments, the system may not fail completely, but undergoes degradation, and the system productivity might decrease. Meanwhile, at the same time, the system may be vulnerable to shocks. A single-unit system prone to degradation and shocks is proposed in this study, and emphasis is placed upon determining its availability and cost rate.Design/methodology/approachThe considered single-unit system is expected to have three states, namely, normal, degraded and failed. As the system enters the degraded state, it is said to be partially failed. The degraded state incurs higher degradation than the normal state and is more prone to shocks. Inspections are used to determine the state and failure type of the system. Inspections are predetermined to be carried out sequentially at time I, I+aI, I+aI+a2I,… where 0 < a ≤ 1, until the detection of degradation/failure. Perfect repairs are conducted instantly on spotting the partial/complete failure. Two cases have been considered of repair taking constant times and random times.FindingsExplicit results on the reliability, availability (both point and limiting availability) and long-run average cost rate (LRACR) of a sequentially inspected single-unit system prone to degradation and shocks under constant and random repair times are given. Numerical example of an oil pipeline system is taken to clarify the acquired results.Originality/valueA sequentially inspected single-unit system prone to degradation and shock is studied unlike done previously.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49067436","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}
Pub Date : 2021-09-13DOI: 10.1108/ijqrm-05-2021-0132
Hind Lafquih, Saad Lissane Elhaq, Issam Krimi, Mouna Berquedich
PurposeAccording to United Nations reports, the worldwide population is expected to reach around 9.6 billion by 2050. This forecasting emphasizes the role of phosphate-based fertilizers for developing sustainable agriculture and ensures the demand all over the planet. From this perspective, phosphate companies are racing to improve their industrial performance and guarantee the quality, reliability and integrity of information efficiently. The purpose of this paper is to propose a traceability system framework that ensures product quality tracing and real-time operations monitoring for open-pit mines.Design/methodology/approachThe authors develop a hybrid approach that integrates Business Process Model and Notation techniques with System Modeling Language to formalize several use cases and scenarios to model quality traceability processes related to open-pit mines. This framework also embeds an optimization module based on mathematical modeling approaches to optimize stockpiles’ movement and respect the distinction between different qualities.FindingsThis paper explains a successful implementation of a quality traceability tool for an African mining company. The research team was able to understand and scale down the problem faced by the managers. Further, the study is focused on improving quality tracing over time and automatizing the current compliance processes related to the mine extraction activities. The proposed tool is proved highly effective in reducing the time of tracing quality claims by 46% compared with the manual procedure. Second, the implementation of this tool reduced fuel costs by 34% and CO2 emissions by 10%.Originality/valueThe originality of the contributions lies in four aspects: (1) adapting quality traceability concept for the mining industry; (2) assessing the current trends of traceability systems considering the mining industry context; (3) hybridizing business processes re-engineering, quality system and optimization modeling; and (4) using a real case study of a phosphate company to evaluate the framework.
{"title":"Modeling and analysis of a quality traceability framework for phosphate extraction process: evidence from Morocco","authors":"Hind Lafquih, Saad Lissane Elhaq, Issam Krimi, Mouna Berquedich","doi":"10.1108/ijqrm-05-2021-0132","DOIUrl":"https://doi.org/10.1108/ijqrm-05-2021-0132","url":null,"abstract":"PurposeAccording to United Nations reports, the worldwide population is expected to reach around 9.6 billion by 2050. This forecasting emphasizes the role of phosphate-based fertilizers for developing sustainable agriculture and ensures the demand all over the planet. From this perspective, phosphate companies are racing to improve their industrial performance and guarantee the quality, reliability and integrity of information efficiently. The purpose of this paper is to propose a traceability system framework that ensures product quality tracing and real-time operations monitoring for open-pit mines.Design/methodology/approachThe authors develop a hybrid approach that integrates Business Process Model and Notation techniques with System Modeling Language to formalize several use cases and scenarios to model quality traceability processes related to open-pit mines. This framework also embeds an optimization module based on mathematical modeling approaches to optimize stockpiles’ movement and respect the distinction between different qualities.FindingsThis paper explains a successful implementation of a quality traceability tool for an African mining company. The research team was able to understand and scale down the problem faced by the managers. Further, the study is focused on improving quality tracing over time and automatizing the current compliance processes related to the mine extraction activities. The proposed tool is proved highly effective in reducing the time of tracing quality claims by 46% compared with the manual procedure. Second, the implementation of this tool reduced fuel costs by 34% and CO2 emissions by 10%.Originality/valueThe originality of the contributions lies in four aspects: (1) adapting quality traceability concept for the mining industry; (2) assessing the current trends of traceability systems considering the mining industry context; (3) hybridizing business processes re-engineering, quality system and optimization modeling; and (4) using a real case study of a phosphate company to evaluate the framework.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43694392","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}
Pub Date : 2021-09-09DOI: 10.1108/ijqrm-03-2021-0073
Kah How Teo, K. Tai, V. Schena, L. Simonini
PurposeThis study presents a lifecycle cost model considering multi-level burn-in for operationally unrepairable systems including assembly and warranty costs. A numerical method to obtain system reliability under component replacement during burn-in is also presented with derived error bounds.Design/methodology/approachThe final system reliability after component and system burn-in is obtained and warranty costs are computed. On failure during operation, the system is replaced with another that undergoes an identical burn-in procedure. Cost behaviours for a small and large system are shown in a numerical example.FindingsThere are more cost savings when system burn-in is conducted for a large system whereas a strategy focusing on component burn-in only can also result in cost savings for small systems. In addition, a minimum system burn-in duration is required before cost savings are achieved for these operationally unrepairable systems.Originality/valueThe operationally unrepairable system is a niche class of systems which small satellites fall under and no such study has been conducted before. The authors present a different approach towards the testing of small satellites for a constellation mission.
{"title":"A lifecycle cost model considering both component and system burn-in for operationally unrepairable systems","authors":"Kah How Teo, K. Tai, V. Schena, L. Simonini","doi":"10.1108/ijqrm-03-2021-0073","DOIUrl":"https://doi.org/10.1108/ijqrm-03-2021-0073","url":null,"abstract":"PurposeThis study presents a lifecycle cost model considering multi-level burn-in for operationally unrepairable systems including assembly and warranty costs. A numerical method to obtain system reliability under component replacement during burn-in is also presented with derived error bounds.Design/methodology/approachThe final system reliability after component and system burn-in is obtained and warranty costs are computed. On failure during operation, the system is replaced with another that undergoes an identical burn-in procedure. Cost behaviours for a small and large system are shown in a numerical example.FindingsThere are more cost savings when system burn-in is conducted for a large system whereas a strategy focusing on component burn-in only can also result in cost savings for small systems. In addition, a minimum system burn-in duration is required before cost savings are achieved for these operationally unrepairable systems.Originality/valueThe operationally unrepairable system is a niche class of systems which small satellites fall under and no such study has been conducted before. The authors present a different approach towards the testing of small satellites for a constellation mission.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41912788","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}
Pub Date : 2021-08-27DOI: 10.1108/IJQRM-03-2021-0071
A. Maihulla, I. Yusuf, M. Isa
{"title":"Reliability modeling and performance evaluation of solar photovoltaic system using Gumbel–Hougaard family copula","authors":"A. Maihulla, I. Yusuf, M. Isa","doi":"10.1108/IJQRM-03-2021-0071","DOIUrl":"https://doi.org/10.1108/IJQRM-03-2021-0071","url":null,"abstract":"","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48833956","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}
Pub Date : 2021-08-24DOI: 10.1108/ijqrm-02-2021-0045
Stuti Tandon, Vijay Kumar, V. Singh
PurposeCode smells indicate deep software issues. They have been studied by researchers with different perspectives. The need to study code smells was felt from the perspective of software industry. The authors aim to evaluate the code smells on the basis of their scope of impact on widely used open-source software (OSS) projects.Design/methodology/approachThe authors have proposed a methodology to identify and rank the smells in the source code of 16 versions of Apache Tomcat Software. Further, the authors have analyzed the categorized smells by calculating the weight of the smells using constant weights as well as Best Worst Method (BWM). Consequently, the authors have used Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to determine the rank of versions using constant weights as well as BWM.FindingsVersion 1 of Apache Tomcat has least smell, and version 8 is reported to contain the maximum code smells. Notable differences in both the cases during the trend analysis are reported by the study. The findings also show that increase is observed in the number of code smells with the release of newer versions. This increment is observed till version 8, followed by a subtle marked depreciation in the number of code smells in further releases.Originality/valueThe focus is to analyze smells and rank several versions of Apache Tomcat, one of the most widely used software for code smell study. This study will act as a significant one for the researchers as it prioritizes the versions and will help in narrowing down the options of the software used to study code smell.
{"title":"Empirical evaluation of code smells in open-source software (OSS) using Best Worst Method (BWM) and TOPSIS approach","authors":"Stuti Tandon, Vijay Kumar, V. Singh","doi":"10.1108/ijqrm-02-2021-0045","DOIUrl":"https://doi.org/10.1108/ijqrm-02-2021-0045","url":null,"abstract":"PurposeCode smells indicate deep software issues. They have been studied by researchers with different perspectives. The need to study code smells was felt from the perspective of software industry. The authors aim to evaluate the code smells on the basis of their scope of impact on widely used open-source software (OSS) projects.Design/methodology/approachThe authors have proposed a methodology to identify and rank the smells in the source code of 16 versions of Apache Tomcat Software. Further, the authors have analyzed the categorized smells by calculating the weight of the smells using constant weights as well as Best Worst Method (BWM). Consequently, the authors have used Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) to determine the rank of versions using constant weights as well as BWM.FindingsVersion 1 of Apache Tomcat has least smell, and version 8 is reported to contain the maximum code smells. Notable differences in both the cases during the trend analysis are reported by the study. The findings also show that increase is observed in the number of code smells with the release of newer versions. This increment is observed till version 8, followed by a subtle marked depreciation in the number of code smells in further releases.Originality/valueThe focus is to analyze smells and rank several versions of Apache Tomcat, one of the most widely used software for code smell study. This study will act as a significant one for the researchers as it prioritizes the versions and will help in narrowing down the options of the software used to study code smell.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49390942","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}
Pub Date : 2021-08-24DOI: 10.1108/ijqrm-07-2020-0222
Soumya Roy, B. Pradhan, Annesha Purakayastha
PurposeThis article considers Inverse Gaussian distribution as the basic lifetime model for the test units. The unknown model parameters are estimated using the method of moments, the method of maximum likelihood and Bayesian methods. As part of maximum likelihood analysis, this article employs an expectation-maximization algorithm to simplify numerical computation. Subsequently, Bayesian estimates are obtained using the Metropolis–Hastings algorithm. This article then presents the design of optimal censoring schemes using a design criterion that deals with the precision of a particular system lifetime quantile. The optimal censoring schemes are obtained after taking into account budget constraints.Design/methodology/approachThis article first presents classical and Bayesian statistical inference for Progressive Type-I Interval censored data. Subsequently, this article considers the design of optimal Progressive Type-I Interval censoring schemes after incorporating budget constraints.FindingsA real dataset is analyzed to demonstrate the methods developed in this article. The adequacy of the lifetime model is ensured using a simulation-based goodness-of-fit test. Furthermore, the performance of various estimators is studied using a detailed simulation experiment. It is observed that the maximum likelihood estimator relatively outperforms the method of moment estimator. Furthermore, the posterior median fares better among Bayesian estimators even in the absence of any subjective information. Furthermore, it is observed that the budget constraints have real implications on the optimal design of censoring schemes.Originality/valueThe proposed methodology may be used for analyzing any Progressive Type-I Interval Censored data for any lifetime model. The methodology adopted to obtain the optimal censoring schemes may be particularly useful for reliability engineers in real-life applications.
{"title":"On inference and design under progressive type-I interval censoring scheme for inverse Gaussian lifetime model","authors":"Soumya Roy, B. Pradhan, Annesha Purakayastha","doi":"10.1108/ijqrm-07-2020-0222","DOIUrl":"https://doi.org/10.1108/ijqrm-07-2020-0222","url":null,"abstract":"PurposeThis article considers Inverse Gaussian distribution as the basic lifetime model for the test units. The unknown model parameters are estimated using the method of moments, the method of maximum likelihood and Bayesian methods. As part of maximum likelihood analysis, this article employs an expectation-maximization algorithm to simplify numerical computation. Subsequently, Bayesian estimates are obtained using the Metropolis–Hastings algorithm. This article then presents the design of optimal censoring schemes using a design criterion that deals with the precision of a particular system lifetime quantile. The optimal censoring schemes are obtained after taking into account budget constraints.Design/methodology/approachThis article first presents classical and Bayesian statistical inference for Progressive Type-I Interval censored data. Subsequently, this article considers the design of optimal Progressive Type-I Interval censoring schemes after incorporating budget constraints.FindingsA real dataset is analyzed to demonstrate the methods developed in this article. The adequacy of the lifetime model is ensured using a simulation-based goodness-of-fit test. Furthermore, the performance of various estimators is studied using a detailed simulation experiment. It is observed that the maximum likelihood estimator relatively outperforms the method of moment estimator. Furthermore, the posterior median fares better among Bayesian estimators even in the absence of any subjective information. Furthermore, it is observed that the budget constraints have real implications on the optimal design of censoring schemes.Originality/valueThe proposed methodology may be used for analyzing any Progressive Type-I Interval Censored data for any lifetime model. The methodology adopted to obtain the optimal censoring schemes may be particularly useful for reliability engineers in real-life applications.","PeriodicalId":14193,"journal":{"name":"International Journal of Quality & Reliability Management","volume":" ","pages":""},"PeriodicalIF":2.5,"publicationDate":"2021-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43666538","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}
Pub Date : 2021-08-23DOI: 10.1108/ijqrm-07-2020-0247
Fatemeh Shaker, A. Shahin, Saeed Jahanyan
PurposeThis paper aims to develop a system dynamics (SD) model to identify causal relationships among the elements of failure modes and effects analysis (FMEA), i.e. failure modes, effects and causes.Design/methodology/approachA causal loop diagram (CLD) has been developed based on the results obtained from interdependencies and correlations analysis among the FMEA elements through applying the integrated approach of FMEA-quality function deployment (QFD) developed by Shaker et al. (2019). The proposed model was examined in a steel manufacturing company to identify and model the causes and effects relationships among failure modes, effects and causes of a roller-transmission system.FindingsFindings indicated interactions among the most significant failure modes, effects and causes. Moreover, corrective actions defined to eliminate or relieve critical failure causes. Consequently, production costs decreased, and the production rate increased due to eliminated/decreased failure modes.Practical implicationsThe application of CLD illustrates causal relationships among FMEA elements in a more effective way and results in a more precise recognition of the root causes of the potential failure modes and their easy elimination/decrease. Therefore, applying the proposed approach leads to a better analysis of the interactions among FMEA elements, decreased system's failure rate and increased system availability.Originality/valueThe literature review indicated a few studies on the application of SD methodology in the maintenance area, and no study was performed on the causal interactions among FMEA elements through an FMEA-QFD based SD approach. Although the interactions of these elements are significant and helpful in risks ranking, researchers fail to investigate them sufficiently.
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