Abstract:As the core resource of enterprise value creation,knowledge's life cycle is accelerating and shortening,which leads to the problems of knowledge inefficiency,invalidation and redundancy. Knowledge evolution can effectively alleviate the above problems,improve the quality of case base and improve the application utility of knowledge. In this paper,a case knowledge evolution method based on double-dimensional compression and comprehensive activity is proposed. Firstly,the C4.5-NRS algorithm is used to reduce the case attribute set,and the case base is vertically compressed to reduce the workload of subsequent calculation and the impact of redundant attributes. Secondly,the case space is horizontally compressed based on the improved K-means clustering,and the case clusters to be evolved are delineated by combining the information entropy of the cluster center. Then,the comprehensive activity of the case knowledge to be evolved is obtained based on the indicators of timeliness activity,application activity,scarcity activity and entropy activity. Finally,the evolutionary operation of the case to be evolved is determined according to the established threshold. The simulation results show that the average activity and operation efficiency of the evolved case base are significantly improved. Among them,the double-dimensional spatial compression of the evolution space improves the computing efficiency. By adding update and sleep operations on the basis of the binary operation of retention and deletion,the activity of the cases with medium activity is enhanced to ensure the coordinated development of the stock and quality of the case base.