Browsing by Author "CHEN, ALP"

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ANSWERING HETEROGENEOUS DATABASE QUERIES WITH DEGREES OF UNCERTAINTY
(1993-07-01)
TSENG, FSC
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CHEN, ALP
;
YANG, WP
;
資訊工程學系
;
Department of Computer Science
In heterogeneous database systems, partial values have been used to resolve some schema integration problems. Performing operations on partial values may produce maybe tuples in the query result which cannot be compared. Thus, users have no way to distinguish which maybe tuple is the most possible answer. In this paper, the concept of partial values is generalized to probabilistic partial values. We propose an approach to resolve the schema integration problems using probabilistic partial values and develop a full set of extended relational operators for manipulating relations containing probabilistic partial values. With this approach, the uncertain answer tuples of a query are associated with degrees of uncertainty (represented by probabilities). That provides users a comparison among maybe tuples and a better understanding on the query results. Besides, extended selection and join are generalized to alpha-selection and alpha-join, respectively, which can be used to filter out maybe tuples with low probabilities-those which have probabilities smaller than alpha.
FINDING A COMPLETE MATCHING WITH THE MAXIMUM PRODUCT ON WEIGHTED BIPARTITE GRAPHS
(1993-03-01)
TSENG, FSC
;
YANG, WP
;
CHEN, ALP
;
資訊工程學系
;
Department of Computer Science
The traditional bipartite weighted matching problem is to maximize the largest possible sum of weights. In this paper, we define a bipartite matching problem which maximizes the largest possible product of weights and develop an algorithm to solve it. Although this problem corresponds to a non-linear program, we show this problem can be easily solved by modifying the Hungarian method. Finally, we present an application of this problem.