JISE


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Journal of Information Science and Engineering, Vol. 22 No. 1, pp. 199-213


A Study of Disjunctive Information in Fuzzy Relational Databases

Ming-Hua Wang1, Huan-Chao Keh2, Nan-Chen Hsien3 and Tsong-Sheng Wang2 
1Department of Information Management 
Nanya Institute of Technology 
Chungli, 320 Taiwan 
2Department of Computer Science and Information Engineering 
Tamkang University 
Tamshui, 251 Taiwan 
3Department of Information Management 
National Taipei College of Nursing 
Taipei, 112 Taiwan 
E-mail: nchsieh@ntcn.edu.tw

    This paper proposes a logical reconstruction of the classical fuzzy relational database model to accommodate fuzzy disjunctive information. In query processing, we use two supplementary measurements, matching information and extra information, to model the concepts of imprecision and uncertainty, respectively. We also use these two supplementary measurements to determine the quality of answers to the query. The answers to the query thus contain sure answers and maybe answers. In addition, we discuss the redundancy problem by presenting a complete set of fuzzy relational algebra with fuzzy disjunctive information. The proposed extended fuzzy relational database model preserves the properties – uniquely-determined and well-defined properties of relational algebra to ensure that the manipulative power of the proposed model is the same as that of the classical fuzzy relational database model.

Keywords: fuzzy relational database, fuzzy disjunctive information, imprecision, uncertainty, quality of answer

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