Abstract: Relevance information is a statistic which measures the non-linear relationships between two qualitative variables. In this paper，we define the oriented relevance information among attributes of information and decision systems，which measures the relevance among attributes of information and decision systems. And based on these definitions, we present a new discriminant theorem of knowledge reduction of information systems. Furthermore, our tests of information systems and inconsistent decision systems prove that our approach is feasible and efficient.

摘要： 关联信息是度量两个定性变量之间非线性关系的一个统计量。本文定义了信息系统以及目标信息系统属性之间的有向关联信息，用来度量信息系统以及目标信息系统属性之间的关联程度，基于此给出信息系统以及目标信息系统的知识约简一种新的判定定理。最后本文以信息系统以及不协调目标信息系统知识约简的实例证明这种知识约简是简单有效的。