Browsing by Author "Wu, JM"

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A simple lower bound for total completion time minimization in a two-machine flowshop
(2005-09-01)
Lin, BMT
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Wu, JM
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資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
The purpose of this study is to present a simple lower bound to facilitate the development of branch-and-bound algorithms for the minimization of total completion time in a two-machine flowshop. The studied problem is known to be strongly NP-hard. In the literature, several lower bounds have been proposed. The bounding technique addressed in this paper is based upon a concept about rearrangement of the parameters of the input instance. The technique is intrinsically simple for computer implementations. We conduct computational experiments for problems with 10-65 jobs. Numerical results from our computational study indicate that the new scheme is very effective in reducing the execution time needed for composing optimal solutions.
Bicriteria scheduling in a two-machine permutation flowshop
(2006-06-15)
Lin, BMT
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Wu, JM
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資訊管理與財務金融系註：原資管所+財金所
;
Department of Information Management and Finance
In this paper we consider a production scheduling problem in a two-machine flowshop. The bicriteria objective is a linear combination or weighted sum of the makespan and total completion time. This problem is computationally hard because the special case concerning the minimization of the total completion time is already known to be strongly NP-hard. To find an optimal schedule, we deploy the Johnson algorithm and a lower bound scheme that was previously developed for total completion time scheduling. Computational experiments are presented to study the relative performance of different lower bounds. While the best known bound for the bicriteria problem can successfully solve test cases of 10 jobs within a time limit of 30 min, under the same setting our branch-and-bound algorithm solely equipped with the new scheme can produce optimal schedules for most instances with 30 or less jobs. The results demonstrate the convincing capability of the lower bound scheme in curtailing unnecessary branching during problem-solving sessions. The computational experience also suggests the practical significance and potential implications of this scheme.
Reaction kinetics and mechanism of BaPbO3 formation
(2000-06-15)
Chang, MC
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Wu, JM
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Cheng, SY
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Chen, SY
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材料科學與工程學系
The influence of starting materials on the formation of BaPbO3 is studied. The reaction kinetics of perovskite BaPbO3 phase formation depends greatly on the phase of lead oxide raw materials. Kinetics of BaPbO3 formation is analyzed by the Johnson-Mehl-Avrami model. The experimental results reveals that the reaction of BaCO3-PbO2 raw materials has a reaction order of n = 5/2, and the reaction is controlled by diffusion. On the other hand, in the case of BaCO3-PbO system, the reaction order n is equal to 1. The formation is controlled by the interface reaction. In the final stage of both systems, the reaction orders are the same of about 0.5. The phases left in the final stage are BaPbO3 and BaCO3. (C) 2000 Elsevier Science S.A. All rights reserved.
The effect of ball-milling solvent on the decomposition properties of Ba(Pb1-xBix)O-3
(2001-03-01)
Chang, MC
;
Wu, JM
;
Cheng, SY
;
Chen, SY
;
材料科學與工程學系
Ba(Pb1-xBix)O-3 compound, which exhibits perovskite structure is a superconducting material. It can be a useful material for resistor when x value equals 0. The conducting behavior of BaPbO3 is liable to be affected during aqueous processing. In contrast, the phenomenon is not found in Ba(Pb0.8Bi0.2)O-3 The milling solvents of water and ethanol have different effect on the stability of perovskite phase. The decomposition of BaPbO3 into BaCO3 and PbO2 is found when CO32- ion exists. The partial substitution of Bi3+ stabilizes the perovskite phase. The stabilization and decomposition of perovskite phase explain the resistivity change with different milling solvents. (C) 2001 Elsevier Science B.V. All rights reserved.