Browsing by Author "Lin, Chen-ju"

Now showing 1 - 6 of 6

A note on Group Selection with multiple quality characteristics: power comparison of two methods
(2019-03-04)
Pearn, W. L.
;
Lin, Chen-ju
;
Chen, Y. H.
;
Huang, J. Y.
;
工業工程與管理學系
The Group Selection problem is an essential problem in the supplier selection process. The objective of the problem is to select a subset of suppliers containing the best among multiple candidate suppliers. Manufacturers should procure parts from the selected suppliers to produce high-quality products. Lin, C.J., W.L. Pearn, J.Y. Huang, and Y.H. Chen [2017. "Group Selection for Processes with Multiple Quality Characteristics." Communications in Statistics - Theory and Methods. doi:] considered the problem under multiple quality characteristics, and proposed the Modified Bonferroni method and the Multiple Comparisons with the Best (MCB) method to tackle the problem. The two methods, however, may select different subset containing the best depending on the magnitude of the differences among the k estimated index values. In this paper, we derive the power function for the Modified Bonferroni method, and compare the power of the two methods with extensive simulations. The results show that the MCB method is more powerful than the Modified Bonferroni method when the actual number of the best process is one. On the other hand, the Modified Bonferroni method significantly outperforms the MCB method when the actual number of the best process is greater than one. The results provide practitioners with useful reference about the properties of the two methods for supplier selection.
Efficient Tool Replacement Procedure Based on Yield Evaluation
(2011-05-01)
Lin, Chen-ju
;
Pearn, W. L.
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Tool wear is an inevitable problem in many machining processes. The problem constitutes an inseparable component of variation and can be considered as a systematic assignable cause of process variability. Tool replacement should be initiated when the yield drops below a certain level. Determining the best time for tool replacement is essential to balance between production quality and tool utilization. The yield index, S(pk), has been effectively applied to assess the yield of processes. However, its ordinary measure is inaccurate when data is contaminated by inseparable nonrandom variation. Yield evaluation becomes imprecise when a process is subjected to the tool wear problem. Thus, this paper presents an efficient procedure that determines the best time to replace tools under an extremely low fraction of defectives. The variation from assignable causes is removed by using the linear regression technique. A modified estimator of the S(pk) index with its distribution is proposed to evaluate the processes with the tool wear problem.
Group selection for processes with multiple quality characteristics
(2018-01-01)
Lin, Chen-ju
;
Pearn, W. L.
;
Huang, J. Y.
;
Chen, Y. H.
;
工業工程與管理學系
Evaluating and comparing process capabilities are important tasks of production management. Manufacturers should apply the process with the highest capability among competing processes. A process group selection method is developed to solve the process selection problem based on overall yields. The goal is to select the processes with the highest overall yield among I processes under multiple quality characteristics, I > 2. The proposed method uses Bonferroni adjustment to control the overall error rate of comparing multiple processes. The critical values and the required sample sizes for designated powers are provided for practical use.
Group selection for production yield among k manufacturing lines
(2011-04-01)
Lin, Chen-ju
;
Pearn, Wen Lea
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Producing qualified items or products is essential to meet the requirement preset by customers. Evaluation and selection of desired manufacturing lines become challenging tasks for decision makers. Production yield is one of the important factors in measuring production performance. The goal of this paper is to screen a group of manufacturing lines and identify the best one with the highest yield. For the production lines with extremely low fraction of defectives, the yield index, S(pk), is an efficient indicator for quality level. This paper considers the production selection problem by using S(pk) to compare k (k > 2) manufacturing lines. A subset is constructed to contain the production lines with the highest yield. A systematic approach of test order k compares selected pairs of manufacturing lines along with the Bonferroni method is proposed to solve this problem. Each pair of production yields is compared by taking ratio. The paper provides critical values and required sample sizes of the group selection procedure. An application example on evaluating four power inductor productions is presented to illustrate the practicality of the proposed approach. (C) 2010 Elsevier B.V. All rights reserved.
Process Selection for Higher Production Yield Based on Capability Index S(pk)
(2010-04-01)
Lin, Chen-ju
;
Pearn, W. L.
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Process selection is the problem of comparing two processes and selecting the one that has a higher capability value. In this paper, we consider the process selection problem by using the yield index S(pk) to compare two production processes and select one that has higher production yield. An analytical exact approach is proposed to solve this problem. Testing hypotheses with two phases for comparing two processes are developed. Critical values of the test are obtained to determine the selection decisions. Sample sizes required for designated selection power and confidence level are also investigated. The results provide useful information to practitioners. An application example on comparing two thin-film transistor (TFT) type liquid-crystal display (LCD) production processes is presented to illustrate the practicality of the proposed approach to a real problem in the factory. Copyright (C) 2009 John Wiley & Sons, Ltd.
Process Selection for Higher Production Yield Based on Capability Index S-pk
(2010-04-01)
Lin, Chen-ju
;
Pearn, W. L.
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
Process selection is the problem of comparing two processes and selecting the one that has a higher capability value. In this paper, we consider the process selection problem by using the yield index S-pk to compare two production processes and select one that has higher production yield. An analytical exact approach is proposed to solve this problem. Testing hypotheses with two phases for comparing two processes are developed. Critical values of the test are obtained to determine the selection decisions. Sample sizes required for designated selection power and confidence level are also investigated. The results provide useful information to practitioners. An application example on comparing two thin-film transistor (TFT) type liquid-crystal display (LCD) production processes is presented to illustrate the practicality of the proposed approach to a real problem in the factory. Copyright (C) 2009 John Wiley & Sons, Ltd.