动态信息系统中一种基于条件熵的核属性计算方法

A Calculation Method for Core Attributes Based on Conditional Entropy in Dynamic Information Systems

针对动态信息系统中新增和退出对象集的情况,在信息观下提出了一种基于条件熵的核属性计算方法。先分别讨论仅有对象集进入、仅有对象集退出以及以上两种情形同时存在下条件熵的变化机制。由条件熵变化机制,通过构造支持度矩阵和增量矩阵方式将新增或者退出的对象集一并参与比较计算,快速求得条件熵,进而获得核属性。最后,由实例分析验证该方法的有效性。

The situation that some objects immigrate the system and some objects emigrate the system simultaneously exists in dynamical information systems.In this paper,a calculation method for core attributes is proposed in information view.First,the changing mechanism of condition entropy is analyzed from three different cases,whick include the objects＇ immigration or emigration and that this two cases coexisted.Based on the mechanism,the new condition entropy is computed quickly by support matrixes and incremental matrixes.These matrixes can constructed by computing the objects immigrated or emmigrated at the same time.Then core attributes are obtained quickly.Finally,the validity of the method has been depicted by a practical example.