F Hosseinzadeh Lotfi; M. Piri
Volume 3, Issue 3 , September 2014, , Pages 69-74
Abstract
Data Envelopment Analysis (DEA) is a nonparametric method for measuring the efficiency of Decision Making Units (DMUs) which was first introduced by Charnes, Cooper and Rhodes in1978 as the CCR model .One of the most important topics in management science is determining the efficiency of DMUs. DEA technique ...
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Data Envelopment Analysis (DEA) is a nonparametric method for measuring the efficiency of Decision Making Units (DMUs) which was first introduced by Charnes, Cooper and Rhodes in1978 as the CCR model .One of the most important topics in management science is determining the efficiency of DMUs. DEA technique is employed for this purpose. In many DEA models, the best performance of a DMU is indicated by an efficiency score of one. There is often more than one DMU with this efficiency score. To rank and compare efficient units, many methods have been introduced. Moreover, the main assumption in all DEA models was that all input and output values are positive, but practically, we encounter many cases that violate this term and we ultimately have negative inputs and outputs.
N. Manavizadeh; E. Azizi Javan
Volume 3, Issue 2 , May 2014, , Pages 24-32
Abstract
Shop floor performance has great influence on performance of a manufacturing system. Traditionally, shop floor operational policies concerning maintenance scheduling, quality control and production scheduling have been considered and optimized independently. Anyway, these aspects of operations planning ...
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Shop floor performance has great influence on performance of a manufacturing system. Traditionally, shop floor operational policies concerning maintenance scheduling, quality control and production scheduling have been considered and optimized independently. Anyway, these aspects of operations planning have an interaction effect on each other significantly and hereupon for improving the system performance; they need to be considered commonly. The main objective of this study is to provide a new approach in the quality control process. x control chart has been used in previous models, but in this study to improve the quality and increase the accuracy, cumulative sum control chart which is useful for detecting small changes by considering previous information of process is used and causes 5% improvement in objective function in the case that x control chart was used.