Browsing by Author "Chan, Chien-Chung"

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Bit-Vector Representation of Dominance-Based Approximation Space
(2011)
Chan, Chien-Chung
;
Tzeng, Gwo-Hshiung
;
科技管理研究所
;
Institute of Management of Technology
Dominance-based Rough Set Approach (DRSA) introduced by Greco et al. is an extension of Pawlak\'s classical rough set theory by using dominance relations in place of equivalence relations for approximating sets of preference ordered decision classes. The elementary granules in DRSA are P-dominating and P-dominated sets. Recently, Chan and Tzeng introduced the concept of indexed blocks for representing dominance-based approximation space with generalized dominance relations on evaluations of objects. This paper shows how to derive indexed blocks from P-dominating and P-dominated sets in DRSA. Approximations are generalized to any family of decision classes in terms of indexed blocks formulated as binary neighborhood systems. We present algorithms for generating indexed blocks from multi-criteria decision tables and for encoding indexed blocks as bit-vectors to facilitate the computation of approximations and rule generation. A new form of representing decision rules by using interval and set-difference operators is introduced, and we give a procedure of how to generate this type of rules that can be implemented as SQL queries.
Business Aviation Decision-Making Using Rough Sets
(2008)
Yang, Yu-Ping On
;
Shieh, How-Ming
;
Tzeng, Gwo-Hshiung
;
Yen, Leon
;
Chan, Chien-Chung
Business aviation has been popular in the United States, Europe, and South America, however, top economies in East Asia, including Japan, Korea, and Taiwan, have been more conservative and lag behind in the development of business aviation. In this paper, we hope to discover possible trends and needs of business aviation for supporting the government to make decision in anticipation of eventual deregulation in the near future. We adopt knowledge-discovery tools based on rough set to analyze the potential for business aviation through an empirical study. Although our empirical study uses data from Taiwan, we are optimistic that our proposed method can be similarly applied in other countries to help governments there make decisions about a deregulated market.
Combined rough sets with flow graph and formal concept analysis for business aviation decision-making
(2011-06-01)
Yang, Yu-Ping Ou
;
Shieh, How-Ming
;
Tzeng, Gwo-Hshiung
;
Yen, Leon
;
Chan, Chien-Chung
Although business aviation has been popular in the USA, Europe, and South America, however, top economies in East Asia, including Japan, Korea, and Taiwan, have been more conservative and lag behind in the development of business aviation. In this paper, we hope to discover possible trends and needs of business aviation for supporting the government to make decision in anticipation of eventual deregulation in the near future. We adopt knowledge-discovery tools based on rough set to analyze the potential for business aviation through an empirical study. Although our empirical study uses data from Taiwan, we are optimistic that our proposed method can be similarly applied in other countries to help governments there make decisions about a deregulated market in the future.
Computing Approximations of Dominance-Based Rough Sets by Bit-Vector Encodings
(2008)
Chan, Chien-Chung
;
Tzeng, Gwo-Hshiung
;
科技管理研究所
;
Institute of Management of Technology
This paper introduces a mechanism for computing approximations of Dominance-Based Rough Sets (DBRS) by bit-vector encodings. DBRS was introduced by Greco et al. as an extension of Pawlak\'s classical rough sets theory by using dominance relations in place of equivalence relations for approximating sets of preference ordered decision classes. Our formulation of dominance-based approximation spaces is based on the concept of indexed blocks introduced by Chan and Tzeng. Indexed blocks are sets of objects indexed by pairs of decision values where approximations of sets of decision classes are defined in terms of exclusive neighborhoods of indexed blocks. In this work, we introduced an algorithm for updating indexed blocks incrementally, and we show that the computing of dominance-based approximations can be accomplished more intuitively and efficiently by encoding indexed blocks as bit-vectors. In addition, bit-vector encodings can simplify the definitions of lower and upper approximations greatly. Examples are given to illustrate presented concepts.
Dominance-based rough sets using indexed blocks as granules
(2008)
Chan, Chien-Chung
;
Tzeng, Gwo-Hshiung
;
科技管理研究所
;
Institute of Management of Technology
Dominance-based rough set introduced by Greco et al. is an extension of Pawlak's classical rough set theory by using dominance relations in place of equivalence relations for approximating sets of preference ordered decision classes satisfying upward and downward union properties. This paper introduces a formulation of approximation spaces based on multiple criteria decision tables by using the concept of indexed blocks, which are sets of objects indexed by pairs of decision values. The approximations of sets of decision classes are formulated in terms of exclusive neighborhoods of indexed blocks. We show that the set of indexed blocks with exclusive neighborhoods forms a partition on the universe of objects when approximating preference ordered decision classes with upward and downward union properties. Examples are given to illustrate presented concepts.
Dominance-Based Rough Sets Using Indexed Blocks as Granules
(2009)
Chan, Chien-Chung
;
Tzeng, Gwo-Hshiung
;
科技管理研究所
;
Institute of Management of Technology
Dominance-based rough set introduced by Greco et al. is an extension of Pawlak's classical rough set theory by using dominance relations in place of equivalence relations for approximating sets of preference ordered decision classes satisfying upward and downward union properties. This paper introduces the concept of indexed blocks for representing dominance-based approximation spaces. Indexed blocks are sets of objects indexed by pairs of decision values. In our study, inconsistent information is represented by exclusive neighborhoods of indexed blocks. They are used to define approximations of decision classes. It turns out that a set of indexed blocks with exclusive neighborhoods forms a partition on the universe of objects. Sequential rules for updating indexed blocks incrementally are considered and illustrated with examples.
SEMICONDUCTOR MARKET FLUCTUATION INDICATORS AND RULE DERIVATIONS USING THE ROUGH SET THEORY
(2009-06-01)
Huang, Chi-Yo
;
Tzeng, Gwo-Hshiung
;
Chan, Chien-Chung
;
Wu, Hong-Chun
;
科技管理研究所
Semiconductors are the most important components in most electronic systems. The semiconductor market exhibits highly cyclical behavior, which has become one of the major impact factors for world economic performance. Meanwhile, the wealth of the leading countries in the semiconductor industry, e.g. South Korea and Taiwan, depends highly on the semiconductor market situation. Although important, very few studies have focused on deriving general indicators or rules for predicting semiconductor market fluctuations. Instead, existing research focuses mainly on discussing specific reasons for explaining one or a few past semiconductor industry business cycle(s). Such rules of thumb, which are intended to serve as foundations for policy definitions, strategic planning and investment decisions, are complex and cannot be easily followed to predict future semiconductor market fluctuations. On the other hand, a rule-based forecasting (RBF) framework will be very helpful for real world managers' and policy makers' applications. Thus, the purpose of this research is to derive a set of general rules for predicting future semiconductor market fluctuations. Based on historical data, a set of basic indicators serving as inputs for algorithms developed based on the rough set theory (RST) will first be summarized using the brainstorming approach followed by semiconductor industry experts. Then the fluctuations of the basic indicators from 1978 to 2004 will be transformed into seven levels of linguistic variables from high growth (HG) to high recession (HR). After the transformation of growth rates into linguistic variables, a set of general rules for predicting future semiconductor market industry fluctuations will be derived using RST. Finally, general rules and a set of indicators are presented for government policy definition, industry strategic planning, investment analysis and so on. As a result, 18 indicators and 12 rules are derived. The results demonstrate that when the semiconductor capital spending grows strongly or the European Union (EU) Gross Domestic Product (GDP) grows strongly when the crude oil price remains unchanged, the semiconductor market will grow strongly. Meanwhile, when the electronic system production. declines severely, the semiconductor market will also be in a severe recession. By applying the decision rules derived using RST on 2005 semiconductor market fluctuations, we found the proposed RBF framework feasible and can predict the 2005 semiconductor market fluctuation precisely.