To solve this problem,this paper analyzes the traditional methods of case base maintenance and proposes a case-saving strategy based on case cover capability to limit the infinite expanding of the case base.

Analysis of the influence of unsteady movements of mobile communication satellites on their coverage performance;

Simulation results show that the optimal common-track constellation can provide favorable coverage performance to China with fewer satellites, and hence is appro.

This paper,with the theory and method of fractal,sets up respectively fractal models for the coverage and connectivity of urban road network.

The criterions of rule extraction conclude the coverage of rules and the veracity of rules.

This work discusses the special relationship between the sensor range and the communication range in WSN, and researches on the deployment methods in closed or semi-closed area with particular shape, also figures out an optimal deployment algorithm which can satisfy both coverage and connectivity by using nodes as few as possible.

A few papers,like Refs 1,2,3 and 4,have studied constellation coverage.

In this paper,we introduce recent progress on selection theory and its related topics,such as,retract theory,continuous insertion property,generalized metric spaces and covering properties.