Browsing by Author "Choudhury, Gautam"

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Analysis of the Machine Repair Models With Multi-Threshold Synchronous Vacations
(2013-05-01)
Wu, Chia-Huang
;
Ke, Jau-Chuan
;
Choudhury, Gautam
;
工業工程與管理學系
;
Department of Industrial Engineering and Management
In this paper, we present an analysis of a machine repair problem with M operating machines and S standbys, in which c repairmen are responsible for supervising these machines and follow a multi-threshold, synchronous vacation policy. With such a policy, at a repair completion instant, if the number of the failed machines in the system is less than a preset threshold value, partial idle servers together take a single vacation (or leave for a random amount of time doing other secondary job). At the end of a vacation, they return to repair the failed machines (or waits for the arrival). The steady-state probabilities are solved by using the matrix-analytic method, and formulae of system performance measures are thereby obtained. A cost model is then developed to formulate an optimization problem to find the minimum cost. The direct search and quasi-Newton methods are implemented to determine the optimal number of servers, the optimal threshold policy and the optimal repair rate.