Browsing by Author "Wang, Li-Chih"

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A multi-granularity approach for estimating the sustainability of a factory simulation model: semiconductor packaging as an example
(2018-10-01)
Chen, Toly
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Wang, Li-Chih
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Chiu, Min-Chi
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工業工程與管理學系
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Department of Industrial Engineering and Management
Dynamic factory simulation has been considered as an effective means to control a factory. However, the large amount of money, time, efforts, and know-how required for conducting a factory simulation study force a factory to pursue the persistent application of the factory simulation model, i.e. the sustainability of the factory simulation model. Therefore, strategies are required to facilitate the rapid establishment of the factory simulation model, to lower the technical requirements of the model, and to reduce the effort and time spent on simulation tasks, thus increasing users' willingness to continue the application of the model. However, such issues have rarely been discussed. In addition, no method is available for estimating the sustainability of a factory simulation model. To address this problem, short-time evidence was analyzed rather than observing data over a long period. Then, a multi-granularity approach is proposed to estimate the sustainability of a factory simulation model based on these evidences. The proposed methodology has been applied to the simulation of a real semiconductor packaging facility. According to the experimental results, the multi-granularity approach reduced the input space by 89% and maintained a very high estimation accuracy. In addition, it also saved considerable time in building the models for estimating sustainability. Furthermore, without the multi-granularity approach, the sustainability of the factory simulation model could be observed only after a long period.
Integer nonlinear programming and optimized weighted-average approach for mobile hotel recommendation by considering travelers' unknown preferences
(2018-10-01)
Lin, Yu-Cheng
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Chen, Toly
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Wang, Li-Chih
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工業工程與管理學系
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Department of Industrial Engineering and Management
The existing mobile hotel recommendation systems are usually subject to a difficult problem-travelers choose dominated hotels. This problem is difficult to resolve because there is no reason to recommend a hotel that is inferior to another in all aspects. To address this problem, an artificial dimension is added to each hotel to model unknown personal preferences. The possible values along the artificial dimension and the weight associated with it are derived by solving an integer nonlinear programming problem. Thus, the proposed methodology hybridizes objective and subjective weights. An illustrative example is provided to show the applicability of the proposed methodology. In addition, a field study was conducted in a small region of Seatwen District, Taichung City, Taiwan to evaluate the possible advantages of the proposed methodology over existing methods. The experimental results showed that the proposed methodology outperformed five existing methods in improving the successful recommendation rate, with the most significant advantage being up to 33 %. Furthermore, the recommendation results generated using the proposed methodology were found to be less risky.
Microwave Absorption Properties of Silver Doped MWCNT Buckypaper
(2013)
Tsao, Che-Wei
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Saravanan, L.
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Liu, Jih-Hsin
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Miao, Hsin-Yuan
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Wang, Li-Chih
Microwave absorbing property of composites containing Ag nanoparticles filled multiwalled carbon nanotube buckypaper (Ag-BP) has been investigated. Buckypaper doped with silver was prepared by direct dispersion and filtration method. From the low temperature resistivity measurement it was found that increasing doping level decreases the electrical conductivity of the buckypaper. 30 wt. % and 40 wt. % of Ag-BP samples shows the maximum transmission coefficient, with very high conductivity. The results demonstrate that microwave absorption of Ag-BP was attributed only due to the dielectric loss rather than other losses. The absorption peak frequency of the Ag/MWCNTs-BP can be controlled easily in the presence of Ag nanoparticles into the CNT mats.