Parham Azimi; Farhad Hadinejad
Abstract
Reliability optimization and mean time to failure are those of the areas of interest for engineers and designers of systems and the use of redundancy components is one of the most common approaches in this field. The purpose of the optimization problem, finding the optimum number of redundancy components ...
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Reliability optimization and mean time to failure are those of the areas of interest for engineers and designers of systems and the use of redundancy components is one of the most common approaches in this field. The purpose of the optimization problem, finding the optimum number of redundancy components that must be satisfied the objectives of reliability engineering in the system. But usually the reliability improves results in increased costs and changes in parameters such as volume and weight of the system; therefore, it is necessary to establish a balance between resources. In previous researches, redundancy allocation problem is studied with non-repairable components or failure rate with exponential distribution; but in this study, repairable components and rates of failure and repair a non-exponential distribution assumed. Thus the purpose of this paper is solving reliability redundancy allocation problem with the goals of increasing the mean time to failure, reduce costs and reduce the variance of the shelf life of the system, while taking into account constraints such as volume and weight of the system. To this end, the research effort will be using mathematical and statistical techniques such as multi criteria decision making models, design of experiments, simulations, and computer software associated with them, provide a new approach for solving reliability redundancy allocation problem in series-parallel systems with repairable components
Ezatollah Asgharizade; Rahim Ehsani; Farajolah Valipour Halabi
Volume 9, Issue 23 , December 2011, , Pages 21-48
Abstract
Nowadays evaluation system existence is necessary because of wondrous changes in management knowledge. None existence of evaluation system in the different organization dimensions especially in the level of managers is one of the signals that shows the organization problem. The aim of this research is ...
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Nowadays evaluation system existence is necessary because of wondrous changes in management knowledge. None existence of evaluation system in the different organization dimensions especially in the level of managers is one of the signals that shows the organization problem. The aim of this research is combing of 360degree method and technical VIKOR for evaluating performance. The statically society in this research is included from13persons of Research Center managers. Performance evaluation criteria are prepared from expert opinions with Delphi method and visionary basis. Questioner's perpetuity is supported with Cronbach's alpha correlation (0.92). Achieving the managers' suitable ranking is the result of combing 360degree method and technical VIKOR that the capability of it is proved in research center. The total of the subordinates and self-evaluator idea is equal to the superior ideas. Using of the weight stability intervals formula in other MADM technique for criteria weights sensitivity analysis is completely similar with reality decision making environment.
