Browsing by Author "Wang, WP"

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A new content-based access method for video databases
(1999-09-01)
Cheng, PJ
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Wang, WP
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資訊工程學系
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Department of Computer Science
This paper presents a novel video data model and a nested annotation language for describing complex information of video data. In contrast to conventional approaches, the proposed model classifies different video materials of interest to users into different representation frameworks according to their individual properties. It makes the model flexible and capable of sharing video materials. The nested annotation language effectively describes scenarios in video data and can be effectively analysed. With the assistance of domain knowledge and index organizations this investigaton also develops algorithms to effectively process five types of familiar video queries: semantic query, temporal quaery, similar query, fuzzy query and hybrid query. In addition, a SQL-like query language for video content retrival is provided. Experimental results indicate that combining the concepts of Bayesian networks and inheritance of attributes by context significantly improves the content based retrieval of video data. Moreover a prototype system based on proposed model has been implemented. (C) 1999 Published by Elsevier Science Inc. All rights reserved.
Dynamic programming for delayed product differentiation
(2004-07-01)
Hsu, HM
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Wang, WP
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工業工程與管理學系
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Department of Industrial Engineering and Management
Product proliferation and demand uncertainty result in material requirement planning difficulties, which give rise to high inventories and low customer service. A design concept, delayed product differentiation, is advocated for reducing the impact due to inaccurate forecasts and shortening the order response time. In this paper, a dynamic programming model using an AND/OR graph is constructed to determine the product differentiation points. Taking into account the costs and benefits associated with delayed product differentiation points, we proposed an approach to suggest whether the designer ought to differentiate specific products from the common part set at each design stage. Finally, we illustrate an example to characterize the optimal product differentiation points. (C) 2003 Elsevier B.V. All rights reserved.
Improved field-emission properties of carbon nanotube field-emission arrays by controlled density growth,of carbon nanotubes
(2005-01-01)
Juan, CP
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Chen, KJ
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Tsai, CC
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Lin, KC
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Hong, WK
The density distribution of CNTs is one of the. crucial parameters determing the field-emission property of CNTs. To effectively control the density of CNTs, an inactive thin-film layer was deposited on a catalyst. The results showed that improved field emission property could be obtained with a thin SiO layer on the catalyst layer as the precursor. For 3.5 nm Fe and 3.5 nm SiO on 3.5 nm Fe as a catalyst, the turn-on field could be decreased from 3.7 V/mum. to 2.2 V/mum and the field-emission current density increased from 2.6 x 10(-8) A/cm(2) to 2.4 x 10(-4) A/cm(2) when the applied field was 4 V/mum.
Modeling demand driven with forecast regulation, safety stock setting and capacity analysis
(2000-09-01)
Hsu, HM
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Wang, WP
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工業工程與管理學系
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Department of Industrial Engineering and Management
High demand uncertainty has been a major challenge for production planning in assemble-to-order (ATO) environments. Regulating dealers' demand forecasts, determining appropriate safety stock levels and deciding required capacity levels are some of the typical problems solved by ATO firms. The main objective in this study is therefore to construct a mathematical model to deal with the aforementioned managerial, problems under the consideration of product life cycle. According to the various cost and demand characteristics in different phases of a product life cycle, production managers may apply the proposed model to find a near optimal solution set of regulation factors for dealers' demand forecasts, appropriate levels of safety stocks and the number of key machines. Finally, an example is given to illustrate our model. Significance: This paper presents a linear programming model that integrates the activities of forecasting adjustment, material preparation and key machine quantity determination in an ATO environment. The proposed model reflects the phenomena of a product life cycle passing through the different appearances of the demand and cost in distinct phases.
Possibilistic programming in production planning of assemble-to-order environments
(2001-04-01)
Hsu, HM
;
Wang, WP
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工業工程與管理學系
;
Department of Industrial Engineering and Management
For the sake of alleviating the influences of demand uncertainty in assemble-to-order (ATO) environments, the strategies of regulating dealers' forecast demands, determining appropriate safety stocks, and deciding the numbers of key machines are usually adopted by manufacturers. In this paper, we propose a possibility linear programming model to manage these production planning problems. The proposed model accomplishes forecasting adjustments, material management, and production activities. Because of price fluctuations, material obsolescence, and the time value of, capital. the ambiguity of cost is considered in the objective function of the model. We substituted the fuzzy objective function with three crisp objectives: minimizing the most possible cost, maximizing the possibility of obtaining lower cost, and minimizing the risk of obtaining higher cost. Zimmermann's fuzzy programming method is then applied for achieving an overall satisfactory compromise solution. Finally, an example is given to illustrate our model. (C) 2001 Elsevier Science B.V. All rights reserved.