Browsing by Author "Yang, Ming-Hsien"

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Analyzing the effects of family-based scheduling rule on reducing capacity loss of single machine with uncertain job arrivals
(2012-01-01)
Chung, Shu-Hsing
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Yang, Ming-Hsien
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Kao, Ching-Kuei
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工業工程與管理學系
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Department of Industrial Engineering and Management
For a single finite-capacity machine that can process several product types of jobs, uncertainties in job arrival time and product type can make the calculation of required setup time and the setting of output target very complicated. Setup activities may cause wastage in machine capacity and extend job lead time. In such circumstances, the family-based scheduling rule (FSR) can be used to reduce setup frequency and amount of setup time. To efficiently evaluate the effects on capacity-saving, both expected setup time and service time are estimated by the FSR analytic models. The effect of FSR in reducing setup time and capacity loss is explored further by comparing the results with FIFO rule. Finally, the performances of the developed analytic models for estimating setups and setup time are evaluated in the experimental design, and a simulation model is built for accuracy comparisons with the analytic models. (C) 2011 Elsevier Ltd. All rights reserved.
To estimate the stage completion time for a two-stage flexible flow shop with dynamic job arrival
(2008)
Yang, Ming-Hsien
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Chung, Shu-Hsing
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Ka, Ching-Kuei
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工業工程與管理學系
;
Department of Industrial Engineering and Management
Considering the two-stage flexible flow shop with dynamic job arrival, each stage contains identical parallel machines, and the second stage receives jobs with stochastic arriving time from first stage. To estimate the job completion time at each stage is useful to enhance the customer service or production performances. The completion time of jobs at each stage can be determined with the sum of the stage arriving time, the expected stage waiting time, and the expected stage service time of jobs. The expected stage waiting time of job relates to the utilization rates of machines, which should be corrected due to the idleness of machine. The idle time depends on the number of jobs in the system at specific time. The birth-and-death process can be used to describe probabilistically how the number of jobs in the system changes as time increasing. Note the stage service time of jobs relates to the estimated setup time and the processing time of jobs at each stage. To analyze the accuracy on the estimated stage completion time of jobs, a computational test through simulation is conducted to verify the proposed probabilistic model.