Pub Date : 2014-08-25DOI: 10.1504/IJQET.2014.064394
J. Evans, Guangming Chen, J. Y. Evans, J. Bartos
Accelerated life tests allow for reduction of test time to demonstrate targeted life of a component for a given level of reliability. This is accomplished by increasing loads on the component or by compressing the time scale in relation to the service environment. The acceleration factor provides a quantitative estimate of the relationship between the test condition and the field condition for this purpose. This paper provides a detailed process, for developing acceleration factor models for reliability testing of mechanical components. Several examples are given for various types of mechanical components undergoing wear-out processes.
{"title":"Development of acceleration factors for reliability testing of mechanical equipment","authors":"J. Evans, Guangming Chen, J. Y. Evans, J. Bartos","doi":"10.1504/IJQET.2014.064394","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064394","url":null,"abstract":"Accelerated life tests allow for reduction of test time to demonstrate targeted life of a component for a given level of reliability. This is accomplished by increasing loads on the component or by compressing the time scale in relation to the service environment. The acceleration factor provides a quantitative estimate of the relationship between the test condition and the field condition for this purpose. This paper provides a detailed process, for developing acceleration factor models for reliability testing of mechanical components. Several examples are given for various types of mechanical components undergoing wear-out processes.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064394","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692360","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 : 2014-08-25DOI: 10.1504/IJQET.2014.064385
T. Elsmuai, C. McCollin
Accreditation of laboratories has been a subject of considerable interest because product quality guarantee has become one of the prime factors to be considered at this present time of highly competitive industrial activity. Laboratories in the developing countries need to establish a new strategy on accreditation to be able to demonstrate the capability to compete internationally taking account of the difficulties, barriers, confidence and international acceptance. This paper intends to investigate the factors that lead to establishing a sustainable national accreditation body (NAB) and examine employees and management’s attitudes and perceptions toward the development of a sustainable NAB in accordance with ISO/IEC 17011. The analysis has led to development of the main important factors that are directly affecting accreditation programmes in the developing countries. The Bayesian analyses have identified the main drivers of an accreditation model. The outcomes of the analyses are satisfactory because they correspond with the results of the theoretical framework.
{"title":"Bayesian modelling of a quality accreditation network","authors":"T. Elsmuai, C. McCollin","doi":"10.1504/IJQET.2014.064385","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064385","url":null,"abstract":"Accreditation of laboratories has been a subject of considerable interest because product quality guarantee has become one of the prime factors to be considered at this present time of highly competitive industrial activity. Laboratories in the developing countries need to establish a new strategy on accreditation to be able to demonstrate the capability to compete internationally taking account of the difficulties, barriers, confidence and international acceptance. This paper intends to investigate the factors that lead to establishing a sustainable national accreditation body (NAB) and examine employees and management’s attitudes and perceptions toward the development of a sustainable NAB in accordance with ISO/IEC 17011. The analysis has led to development of the main important factors that are directly affecting accreditation programmes in the developing countries. The Bayesian analyses have identified the main drivers of an accreditation model. The outcomes of the analyses are satisfactory because they correspond with the results of the theoretical framework.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064385","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692302","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 : 2014-08-25DOI: 10.1504/IJQET.2014.064404
V. B. Bokov
Conductivity measuring instruments should only be used if they allow carrying out the measurements of required accuracy and format, and are suitable for their measuring environment. This paper introduces a statistical analysis for scaling performance examination of conductivity instruments, enabling analysts to assess if these instruments meet specified requirements. Information is given on how analysts can verify the scaling performance of the instruments using one-way classification analysis of variance and Welch’s approximate t-test. Employing these methods as a useful technique in the field of statistical inference, it was shown that there is a strong correlation between the values of relative errors of measurements and scaling performance of the tested conductivity measuring instruments.
{"title":"Scaling performance examination of microcontroller-based conductivity measuring instruments","authors":"V. B. Bokov","doi":"10.1504/IJQET.2014.064404","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064404","url":null,"abstract":"Conductivity measuring instruments should only be used if they allow carrying out the measurements of required accuracy and format, and are suitable for their measuring environment. This paper introduces a statistical analysis for scaling performance examination of conductivity instruments, enabling analysts to assess if these instruments meet specified requirements. Information is given on how analysts can verify the scaling performance of the instruments using one-way classification analysis of variance and Welch’s approximate t-test. Employing these methods as a useful technique in the field of statistical inference, it was shown that there is a strong correlation between the values of relative errors of measurements and scaling performance of the tested conductivity measuring instruments.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064404","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692425","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 : 2014-08-25DOI: 10.1504/IJQET.2014.064387
E. Telis, G. Besseris, C. Stergiou, M. Limbachiya
This paper presents a methodology for simultaneous optimisation taking into account the key factors for earth retaining structures design, using a real-world case study. These are safety factor, overall cost, total displacements and steel tension. The possible values of the design variables are discrete and its applications often depend on the engineers’ experience, the geotechnical investigation outcome and site accessibility. These variables are chosen based on the ground morphology and on the steel section and temporary prestressed anchors properties. The approach for this simultaneous optimisation of the critical design characteristics of the ‘Berlinoise’ retaining project is based on the desirability analysis – a proven statistical methodology. The presented work was supplemented with the use of finite element analysis. Via this methodology, engineers accurately predict the needed design characteristics, for a robust and financially beneficial study, as long as the input data are properly defined and the design variables values wisely selected.
{"title":"Multivariate optimisation of key factors for construction operations","authors":"E. Telis, G. Besseris, C. Stergiou, M. Limbachiya","doi":"10.1504/IJQET.2014.064387","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064387","url":null,"abstract":"This paper presents a methodology for simultaneous optimisation taking into account the key factors for earth retaining structures design, using a real-world case study. These are safety factor, overall cost, total displacements and steel tension. The possible values of the design variables are discrete and its applications often depend on the engineers’ experience, the geotechnical investigation outcome and site accessibility. These variables are chosen based on the ground morphology and on the steel section and temporary prestressed anchors properties. The approach for this simultaneous optimisation of the critical design characteristics of the ‘Berlinoise’ retaining project is based on the desirability analysis – a proven statistical methodology. The presented work was supplemented with the use of finite element analysis. Via this methodology, engineers accurately predict the needed design characteristics, for a robust and financially beneficial study, as long as the input data are properly defined and the design variables values wisely selected.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064387","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692309","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 : 2014-08-25DOI: 10.1504/IJQET.2014.064408
J. Chimka, Raj Rajagopalan
Where random variables have unknown distributions approximated by triangular distributions, products of random variables cannot be derived, so we are left to observe random samples of such a product and hope it might be well approximated with some familiar distribution. Parameters of the beta distribution are expressed as a second-degree polynomial in c1 and c2, where c1 and c2 are the modes of triangular distributions to be multiplied. Given observations of the responses α1 and α2, and corresponding independent variables c1 and c2, we model the beta distribution parameters as multiple linear functions of their original triangular distribution parameters c1 and c2. Evidence suggests that the product of independent triangular random variables has the approximate distribution of the beta with parameters that are functions of the original triangular random variables’ parameters.
{"title":"Product of triangular distributions with range [0, 1]","authors":"J. Chimka, Raj Rajagopalan","doi":"10.1504/IJQET.2014.064408","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064408","url":null,"abstract":"Where random variables have unknown distributions approximated by triangular distributions, products of random variables cannot be derived, so we are left to observe random samples of such a product and hope it might be well approximated with some familiar distribution. Parameters of the beta distribution are expressed as a second-degree polynomial in c1 and c2, where c1 and c2 are the modes of triangular distributions to be multiplied. Given observations of the responses α1 and α2, and corresponding independent variables c1 and c2, we model the beta distribution parameters as multiple linear functions of their original triangular distribution parameters c1 and c2. Evidence suggests that the product of independent triangular random variables has the approximate distribution of the beta with parameters that are functions of the original triangular random variables’ parameters.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064408","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692001","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 : 2014-08-25DOI: 10.1504/IJQET.2014.064400
Dotan I Shvorin, K. Taaffe
This research demonstrates a unique analytical approach to improving a player’s performance in the game of tennis. We introduce a system development interpretations (SDI) methodology for associating player characteristics and factors in a hierarchical structure. We then show how this tool is applied in a human performance environment such as tennis. This approach was developed as a multi-disciplinary quality tool for process improvement that identifies factor dependencies and depicts their impact on the resulting player performance. From the implementation of the SDI methodology, the research was able to define the tennis player’s difficulties and it has allowed the researchers to build an entire team profile of the Clemson University tennis programme as well as to introduce important conceptual foundations in this field.
{"title":"Improving Tennis Player Performance Using System Development Interpretations Methodology","authors":"Dotan I Shvorin, K. Taaffe","doi":"10.1504/IJQET.2014.064400","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064400","url":null,"abstract":"This research demonstrates a unique analytical approach to improving a player’s performance in the game of tennis. We introduce a system development interpretations (SDI) methodology for associating player characteristics and factors in a hierarchical structure. We then show how this tool is applied in a human performance environment such as tennis. This approach was developed as a multi-disciplinary quality tool for process improvement that identifies factor dependencies and depicts their impact on the resulting player performance. From the implementation of the SDI methodology, the research was able to define the tennis player’s difficulties and it has allowed the researchers to build an entire team profile of the Clemson University tennis programme as well as to introduce important conceptual foundations in this field.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064400","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692378","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 : 2014-08-25DOI: 10.1504/IJQET.2014.064414
A. Badiru
This inaugural write-up of Quality Insights presents a variety of global quality research, thoughts, and perspectives into what quality is all about and why it is important for us never to let up in our pursuit of better quality, no matter how elusive it might appear at first glance. Quality is achievable and there is always room for better quality of products and services. Even behavioural outputs and interpersonal interactions can benefit from better quality.
{"title":"Quality Insights: Global Quality Research, Thoughts, and Perspectives","authors":"A. Badiru","doi":"10.1504/IJQET.2014.064414","DOIUrl":"https://doi.org/10.1504/IJQET.2014.064414","url":null,"abstract":"This inaugural write-up of Quality Insights presents a variety of global quality research, thoughts, and perspectives into what quality is all about and why it is important for us never to let up in our pursuit of better quality, no matter how elusive it might appear at first glance. Quality is achievable and there is always room for better quality of products and services. Even behavioural outputs and interpersonal interactions can benefit from better quality.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-08-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.064414","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692109","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 : 2014-04-15DOI: 10.1504/IJQET.2014.060432
Azadeh Adibi, D. Montgomery, C. Borror
In some applications where the quality characteristic of interest is a profile, it is possible to use multiple linear regressions to model process quality. In this paper, we propose using a P-value approach to evaluate performance of multivariate profiles in Phase II. The average run length (ARL) is used to evaluate performance of the proposed method under different shifts in the model parameters. In our proposed approach, P-values for all observed levels within a sample are calculated. If any P-value is less than a specific threshold, the chart signals out of control. The main advantage of this approach is its ease of implementation in practice. Performance of the proposed method is compared to another commonly used method involving the T2 control charts. Simulation results indicate that the proposed P-value approach performs quite well under the various conditions considered. Given that it is a straightforward and easy to implement approach, as well as a monitoring scheme that only requires a single control chart, the P-value method is quite competitive in practice.
{"title":"A P-value approach for Phase II monitoring of multivariate profiles","authors":"Azadeh Adibi, D. Montgomery, C. Borror","doi":"10.1504/IJQET.2014.060432","DOIUrl":"https://doi.org/10.1504/IJQET.2014.060432","url":null,"abstract":"In some applications where the quality characteristic of interest is a profile, it is possible to use multiple linear regressions to model process quality. In this paper, we propose using a P-value approach to evaluate performance of multivariate profiles in Phase II. The average run length (ARL) is used to evaluate performance of the proposed method under different shifts in the model parameters. In our proposed approach, P-values for all observed levels within a sample are calculated. If any P-value is less than a specific threshold, the chart signals out of control. The main advantage of this approach is its ease of implementation in practice. Performance of the proposed method is compared to another commonly used method involving the T2 control charts. Simulation results indicate that the proposed P-value approach performs quite well under the various conditions considered. Given that it is a straightforward and easy to implement approach, as well as a monitoring scheme that only requires a single control chart, the P-value method is quite competitive in practice.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.060432","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692244","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 : 2014-04-15DOI: 10.1504/IJQET.2014.060428
D. Sarkar, B. Bhattacharjee
Multivariate CUSUM control charts provide a unified scheme to monitor process mean and variability when there are multiple processes that need to be monitored to track the problem causing a change in the quality characteristic of the process. This paper aims at developing a set of multivariate CUSUM control charts for monitoring the quality of ready mixed concrete. On analysing available grades of concrete produced by two commercial batching plants in Ahmedabad, India, it has been observed that after application of multivariate CUSUM control charts along with V mask, if the identified point is the same for three or more quality characteristic then definitely there is a strong indication about occurrence of a problem at that point. The root cause investigation at the identified point would reveal the cause of the change in strength. The remedial action would be to modify the mix design and improve the quality of materials and workmanship.
{"title":"Design and application of multivariate CUSUM for quality monitoring of ready mixed concrete","authors":"D. Sarkar, B. Bhattacharjee","doi":"10.1504/IJQET.2014.060428","DOIUrl":"https://doi.org/10.1504/IJQET.2014.060428","url":null,"abstract":"Multivariate CUSUM control charts provide a unified scheme to monitor process mean and variability when there are multiple processes that need to be monitored to track the problem causing a change in the quality characteristic of the process. This paper aims at developing a set of multivariate CUSUM control charts for monitoring the quality of ready mixed concrete. On analysing available grades of concrete produced by two commercial batching plants in Ahmedabad, India, it has been observed that after application of multivariate CUSUM control charts along with V mask, if the identified point is the same for three or more quality characteristic then definitely there is a strong indication about occurrence of a problem at that point. The root cause investigation at the identified point would reveal the cause of the change in strength. The remedial action would be to modify the mix design and improve the quality of materials and workmanship.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.060428","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692160","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 : 2014-04-15DOI: 10.1504/IJQET.2014.060431
Amit Mitra, Mark M. Clark
The paper focuses on determining changes in process variability of multivariate processes. The problem is compounded by the fact that any of the elements in the variance-covariance matrix of variables could change, leading to a change in the process variability. While it may not be feasible to maintain individual control charts for each element of the variance-covariance matrix, some aggregate measure of the variability criteria could be monitored to initially determine if a change has occurred in the process variability. A couple of aggregate measures are proposed and the performance of these suggested measures is explored through a simulation procedure. Compared to the traditional method, which monitors the determinant of the variance-covariance matrix, these alternatives perform well. The performance measure used is the mean time to first detection of a change in the process variability.
{"title":"Monitoring variability of multivariate processes","authors":"Amit Mitra, Mark M. Clark","doi":"10.1504/IJQET.2014.060431","DOIUrl":"https://doi.org/10.1504/IJQET.2014.060431","url":null,"abstract":"The paper focuses on determining changes in process variability of multivariate processes. The problem is compounded by the fact that any of the elements in the variance-covariance matrix of variables could change, leading to a change in the process variability. While it may not be feasible to maintain individual control charts for each element of the variance-covariance matrix, some aggregate measure of the variability criteria could be monitored to initially determine if a change has occurred in the process variability. A couple of aggregate measures are proposed and the performance of these suggested measures is explored through a simulation procedure. Compared to the traditional method, which monitors the determinant of the variance-covariance matrix, these alternatives perform well. The performance measure used is the mean time to first detection of a change in the process variability.","PeriodicalId":38209,"journal":{"name":"International Journal of Quality Engineering and Technology","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2014-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1504/IJQET.2014.060431","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66692229","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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