Design of hybrid EWMln-S² control chart

ABSTRACT

Memory type control charts have built using logarithmic transformations for the normalization of unbiased sample variance for monitoring of changes in the dispersion of process. The intention of this study is to give a new hybrid exponentially weighted moving average (HEWMA) control chart for monitoring theprocess dispersion. The logarithmic transformation is used to normalize the distribution of sample variance. The execution of the proposed HEWMA control chart is evaluated in accordance with the average run length and standard deviation run length estimated with the help of Monte Carlo method. The proposed HEWMT_n control chart has been compared with the corresponding existing charts to detect increase and decrease in the process variability. It showed that the proposed HEWMT_n control chart is uniformly better than its parallels for detection of shifts in the process variability. A numerical study is also given to understand the operationalization of the proposed control chart.

KEYWORDS:

• Sample variance
• EWMA
• HEWMA
• normal distribution
• simulation

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Saadia Tariq

Saadia Tariq received her Ph.D. degree from NCBAE, Lahore, Pakistan. She has more than five years teaching experience. She has some publications in the area of statistical process control. She is currently working as Assistant Professor at Minhaj University, Lahore, Pakistan. Her research interests include Statistical Process Control.

Muhammad Noor-ul-Amin

Muhammad Noor-ul-Amin received his Ph.D. degree from NCBAE, Lahore, Pakistan. He has been a research fellow at University of Burgundy, France. He has more than five years teaching and research experience. He has various publications in the area of sampling methods and statistical process control. He is currently working as Assistant Professor at COMSATS Institute of Information Technology. His research interests include Statistical Process Control and Sampling Methods.

Muhammad Aslam

Muhammad Aslam did his M.Sc. in Statistics (2004) from GC University Lahore with Chief Minister of the Punjab merit scholarship, M.Phil in Statistics (2006) from GC University Lahore with the Governor of the Punjab merit scholarship, and Ph.D. in Statistics (2010) from National College of Business Administration & Economics Lahore under the kind supervision of Prof. Dr. Munir Ahmad. He worked as a lecturer of Statistics in Edge College System International from 2003–2006. He also worked as Research Assistant in the Department of Statistics, GC University Lahore from 2006 to 2008. Then he joined the Forman Christian College University as a lecturer in August 2009. He worked as Assistant Professor in the same University from June 2010 to April 2012. He worked in the same department as Associate Professor from June 2012 to October 2014. He worked as Associate Professor of Statistics in the Department of Statistics, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia from October 2014 to March 2017. He taught summer course as Visiting Faculty of Statistics at Beijing Jiaotong University, China in 2016. Currently, he is working as a Full Professor of Statistics in department of Statistics, King Abdul-Aziz University Jeddah, and Saudi Arabia. He has published more than 365 research papers in national and international well reputed journals including, for example, IEEE Access, Journal of Applied Statistics, European Journal of Operation Research, Information Sciences, Journal of Process Control, Journal of the Operational Research Society, Applied Mathematical Modeling, International Journal of Fuzzy Systems, Symmetry, International Journal of Advanced Manufacturer Technology, Communications in Statistics, Journal of Testing and Evaluation and Pakistan Journal of Statistics, etc. His papers have been cited more than 3200 times with h-index 30 and i-10 index 92 (Google Scholar). His papers have been cited more than 1900 times with h-index 23 (Web of Science Citations). He is the author of two books published by VDM, Germany and Springer, respectively. He has published eight chapters in well-reputed books. He is also HEC approved Ph.D. supervisor since 2011. He supervised five Ph.D. theses, more than 25 M.Phil theses, and three M.Sc. theses. Dr. Muhammad Aslam is currently supervising two master’s theses in Statistics. He is reviewer of more than 70 well-reputed international journals. He has reviewed more than 150 research papers for various well-reputed international journals. He received meritorious services award in research from National College of Business Administration & Economics Lahore in 2011. He received Research Productivity Award for the year 2012 by Pakistan Council for Science and Technology. His name listed at second Position among Statistician in the Directory of Productivity Scientists of Pakistan 2013. His name listed at first Position among Statistician in the Directory of Productivity Scientists of Pakistan 2014. He got 371 positions in the list of top 2210 profiles of Scientist of Saudi Institutions 2016. He is selected for “Innovative Academic Research & Dedicated Faculty Award 2017” by SPE, Malaysia. He Received King Abdulaziz University Excellence Awards in Scientific Research for the paper entitled “Aslam, M., Azam, M., Khan, N. and Jun, C.-H. (2015). A New Mixed Control Chart to Monitor the Process, International Journal of Production Research, 53 (15), 4684–4693. He Received King Abdulaziz University citation award for the paper entitled “Azam, M., Aslam, M. and Jun, C.-H. (2015). Designing of a hybrid exponentially weighted moving average control chart using repetitive sampling, International Journal of Advanced Manufacturing Technology, 77:1927–1933 in 2018. Prof. Muhammad Aslam introduced the area of Neutrosophic Statistical Quality Control (NSQC) the first time. His is the founder of neutrosophic inferential statistics (NIS) and NSQC. His contribution is the development of neutrosophic statistics theory for the inspection and process control. He originally developed theory in these areas under the Neutrosophic Statistics. He extended the Classical Statistics theory to Neutrosophic Statistics originally in 2018. He is the member of editorial board of Electronic Journal of Applied Statistical Analysis, Neutrosophic Sets and Systems, Asian Journal of Applied Science and Technology, and Pakistan Journal of Commence and Social Sciences. He is also member of Islamic Countries Society of Statistical Sciences. He is appointed as an external examiner for 2016/2017–2018/2019 triennium at The University of Dodoma, Tanzania. His areas of interest include Reliability, Decision Trees, Industrial Statistics, Acceptance Sampling, Rank Set Sampling, Neutrosophic Statistics, and Applied Statistics.

Muhammad Hanif

Muhammad Hanif completed his Masters in Statistics from New South Wales University, Australia with major in Multistage Cluster Sampling. He completed his Ph.D. in Statistics from University of the Punjab, Lahore, Pakistan. He has more than 40 years research experience. He is an author of more than 300 research articles and 10 books. He has served as Professor of Statistics in various parts of the world, i.e. Australia, Libya, Pakistan, and Saudi Arabia. He supervised more than 30 M.Phil. theses and more than 20 Ph.D. dissertations. His areas of interest are Survey Sampling and Control Charts. He is presently working as a professor of Statistics and Vice Rector (Research) at National College of Business Administration and Economics, Lahore, Pakistan.