Spatial join query is a most important query in the spatial database.How to improve the efficiency of a spatial join is a serious question.In this paper,we propose a new algorithm to process spatial join problem.The algorithm is based on the QR-tree,which combines the good property of the R-tree and quadtree.By dividing the space into several subspaces,the algorithm implement the spatial join query on the small R-tree.We compare the algorithm with the R-tree join algorithm of Brinkhoff. Experiments demonstrate the proposed algorithms have high query efficiency.

The importance of information security in e-commerce is expatiated. In response to these problems, a digital signature approach based on the PKI is presented with digital signature technology. An approach for digital signature based on PKI is designed and realized. This approach is very convenient and simple, moreover, it is visual, and the operator needn’t have any special knowledge of digital signature.

The importance of case-retrieving method selection in the CBR system is analyzed, and the defaults of traditional retrieving methods which make use of fuzzy distance to describe the distance in the similar cases are pointed out. A model for case- retrieving based on AHP is presented after the introduction of the basic principle and process of CBR and AHP. With the development environment of CGI, a prototype system is developed, and the running interface is shown.

The importance of case-retrieving method selection in the CBR system is analyzed, and the defaults of traditional retrieving methods which make use of fuzzy distance to describe the distance in the similar cases are pointed out. A model for case- retrieving based on user classification is presented after the introduction of the basic principle and process of CBR. By this case-retrieving method, the retrieving fields are divided into several case bases according to user’s fondness, and it will promote the retrieving speed.

The entropies of structure, information and the effectiveness entropy between knowledge and organization structure are main entropy sources of supply chain network. Entropy model of fractal supply chain network organization structure is established. Fractal knowledge management network outside independently organization structure is built. Finally, the entropies of structure, information and the effectiveness entropy are summed. The model shows that fractal structure has prominent effect of dropping entropy.