模糊關聯資料庫之近似功能相依

On Proximate Functional Dependency of Fuzzy Relational Databases

林宜鋒(Evan IFeng Lin)

指導教授 ： 劉俞志教授

元智大學/資訊學院/資訊管理學系/碩士(2004年)

摘要

功能相依探勘不僅是正規化與不失真分解的依據，更可用來輔助推估屬性中缺值的可能範圍。功能相依的定義取決於屬性值上的等價性，傳統資料庫上兩屬性值必須完全相同才能視為等價的，在延伸可能型模糊資料下，屬性值並非要完全相等才符等價性，可藉由一門檻值與屬性之間的相似度，來定義等價性，目前有多種模糊功能相依應用在此，各有其適用性及意義。本研究考量屬性值間之等價關係可透過與其他屬性值相似度之遞移關係來決定，以此定義值組在屬性上的近似等價性，並定義出近似功能相依。近似等價性具有可在交集的等價關係屬性值上切割出等價群組的好處，並且利用屬性值間相似度關係的最大最小合併封閉包，對值組在各屬性值上加以分群，用以計算近似功能相依，分析其優點並驗證相關定理，並且定義出檢定演算法。

關鍵字

模糊關聯資料庫 ； 近似功能相依 ； 模糊功能相依 ； 近似等價性

並列摘要

Functional dependency in relational database is the basis of normalization and lossless decomposition. Functional dependency can be determined by the equivalence of attribute values. In classical databases, attribute values are equivalence if and only if they are identical. On extended possibility-based fuzzy data model, the attribute values is define equivalence by a threshold value. This paper consider that the transitivity of similarity between attribute values so that define the proximate equivalence of attribute values, and use the proximate equivalence to define the proximate functional dependency. For validating the proximate functional dependency, we also propose a method that use the partition the max-min transitivity closure of the similarity of attribute values to determine proximate functional dependency. Finally we also discuss the inference rule of proximate functional dependency and three algorithms to validate proximate functional dependency.

並列關鍵字

fuzzy relational database ； proximate functional dependency ； fuzzy functional dependency ； proximate equivalence

參考文獻

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