In allusion to the disadvantage of having to obtain the number of clusters of data sets in advance and the sensitivity to selecting initial clustering centers in the k-means algorithm, an improved k-means clustering a...In allusion to the disadvantage of having to obtain the number of clusters of data sets in advance and the sensitivity to selecting initial clustering centers in the k-means algorithm, an improved k-means clustering algorithm is proposed. First, the concept of a silhouette coefficient is introduced, and the optimal clustering number Kopt of a data set with unknown class information is confirmed by calculating the silhouette coefficient of objects in clusters under different K values. Then the distribution of the data set is obtained through hierarchical clustering and the initial clustering-centers are confirmed. Finally, the clustering is completed by the traditional k-means clustering. By the theoretical analysis, it is proved that the improved k-means clustering algorithm has proper computational complexity. The experimental results of IRIS testing data set show that the algorithm can distinguish different clusters reasonably and recognize the outliers efficiently, and the entropy generated by the algorithm is lower.展开更多
With the aim to address the problems presented in knowledge utilization in knowledge-intensive enterprises, the ontology-based proactive knowledge system （OPKS） is put forward to improve knowledge utilization. Proac...With the aim to address the problems presented in knowledge utilization in knowledge-intensive enterprises, the ontology-based proactive knowledge system （OPKS） is put forward to improve knowledge utilization. Proactive knowledge service is taken as the basic idea in the OPKS. The user knowledge requirement is taken as the driving factor and described by the user knowledge requirement. Ontologies are used to present the semantic of heterogeneous knowledge sources and ontology mapping is used to realize the interoperation of heterogeneous knowledge sources. The required knowledge is found by matching the user knowledge requirement with knowledge sources and is provided to the user proactively. System analysis and design of OPKS is carded on by adopting UML. The OPKS is implemented in Java language. Application in a certain institute shows that the OPKS can raise efficiency of knowledge utilization in knowledge-intensive enterprises.展开更多
基金The National Natural Science Foundation of China(No50674086)Specialized Research Fund for the Doctoral Program of Higher Education (No20060290508)the Youth Scientific Research Foundation of China University of Mining and Technology (No2006A047)
文摘In allusion to the disadvantage of having to obtain the number of clusters of data sets in advance and the sensitivity to selecting initial clustering centers in the k-means algorithm, an improved k-means clustering algorithm is proposed. First, the concept of a silhouette coefficient is introduced, and the optimal clustering number Kopt of a data set with unknown class information is confirmed by calculating the silhouette coefficient of objects in clusters under different K values. Then the distribution of the data set is obtained through hierarchical clustering and the initial clustering-centers are confirmed. Finally, the clustering is completed by the traditional k-means clustering. By the theoretical analysis, it is proved that the improved k-means clustering algorithm has proper computational complexity. The experimental results of IRIS testing data set show that the algorithm can distinguish different clusters reasonably and recognize the outliers efficiently, and the entropy generated by the algorithm is lower.
基金The National Natural Science Foundation of China(No50674086)Specialized Research Fund for the Doctoral Program of Higher Education (No20060290508)
文摘With the aim to address the problems presented in knowledge utilization in knowledge-intensive enterprises, the ontology-based proactive knowledge system （OPKS） is put forward to improve knowledge utilization. Proactive knowledge service is taken as the basic idea in the OPKS. The user knowledge requirement is taken as the driving factor and described by the user knowledge requirement. Ontologies are used to present the semantic of heterogeneous knowledge sources and ontology mapping is used to realize the interoperation of heterogeneous knowledge sources. The required knowledge is found by matching the user knowledge requirement with knowledge sources and is provided to the user proactively. System analysis and design of OPKS is carded on by adopting UML. The OPKS is implemented in Java language. Application in a certain institute shows that the OPKS can raise efficiency of knowledge utilization in knowledge-intensive enterprises.
