Study Of Service Discovery Algorithm And Application Migration Model

In mobile environment, the computing capacity of the equipment in users' hands becomes more and more powerful. The smart phones and the wireless network cards provided by the communication enterprises, make it possible for people to access the resources in the network. The 3G technology has improved the network speed and quality. The computers with a 3G netcard become more and more popular. Along with the progress in terminal's computing ability and network quality, people request that pervasive computing be realized. However, in mobile environments several problems still exist. First, the range of people's mobility is big. When people move to a new place, often he can no longer use the original services in the old place. How to make it possible that people can use the services in the new place to complete their tasks without too much distraction from their main job is a very difficult problem. That concerns the application migration in mobile environments. Second, in mobile environments, the bandwidth of the smart equipment is usually limited and unstable. In this situation, the speed of service discovery process may be low. Current algorithms for service discovery can not work very well.Taking the pervasive computing application in mobile environments as the background, this paper discussed the problems existing in pervasive computing in mobile environments, introduced a proper service discovery algorithm, established an application migration model in mobile environments. Through the analysis of current service discovery model, particularly for the features of the mobile environments, we improved current service discovery algorithm, introduced a service discovery algorithm based on the caching mechnism of service lookupers. We established an application migration model in mobile environments to solve the application migration problem in mobile environments. In this paper, we introduced some concepts, such as Task Manager, Context Observer, Environment Manager, Supplier. We also interpreted the function of every part. In AMFME model, the users can find proper services in remote places to satisfy their needs and continue their task.This paper has obtained certain research results in two aspects of service discovery and application migration. Through the experiments in the laboratory, we proved the correctness and usability of the service discovery algorithm. We also proved that this algorithm is better than current algorithms both in speed and quality to discovery services when the network is unstable and bandwith-limited. Through the experiments of simulating real place changing, AMFME can support the application migration very well.Based on the background of pervasive computing in mobile environments, we introduced a service discovery algorithm that is fit for this environment. This is very important for the future work of improving service discovery quality. And the AMFME model can not only provide a new method for application migration, but also direct the projects in reality.