粗集理论及其在旋转机械故障诊断中的应用(一) 粗集理论基本知识

Fault diagnosis of rotating machine based on rough set theory(Ⅰ) Fundamental concepts of rough sets

粗集理论是对不精确、不完整、不确定的数据进行上近似和下近似的计算、分类和约简 ,寻找其隐含的关系和模式 ,产生新的规则 ,确定规则的可信度。介绍了知识库的形式化定义、知识的等价、约简等一些基本概念 。

Based on the principle of rough set theory, calculation of upper and lower approximation and categorization and reduction were performed on inaccurate, insufficient and indefinite data. Data reduction was carried out and implied relation and mode between data were figured out. Thus relative rule were set up and its credibility was established. Fundamental concepts as a theoretical framework, equivalence of knowledge and reduction are discussed. The method that express knowledge base about fault diagnosis of rotating machine is provided.