Research And Application Of Fragmentation In Distributed Resource Space Model

Study on Distributed Data Base System (DDBS) began in the 1970s. This is due to the expansion of demand for database applications and the environment computer hardware changes, especially the rapid development of Computer Networks and Digital Communication Technology. Distributed database systems have emerged and become one of the most active research areas in computer science, because of computer LAN, WAN and the Internet has been widely applied.Database theories, especially the relational data model and theory have gained a great success in the past 40 years. But with the rapid development of Digital Technology and Internet, Web has increasingly become a huge platform for global transmission of information and resources sharing. The existing data models are incapable of effectively managing versatile, distributed and ocean resources in an open and dynamic interconnection environment.To uniformly, normally and effectively manage versatile, distributed and ocean Web resources has become one of the key issues of the next-generation Web. As a new concept of resource management, Resource Space Model focuses on fitting to the new characters of resource. The Resource Space Model is a semantic data model for specifying, storing, managing and locating resources by appropriately classifying the contents of resources. With the development of the RSM and the rapid development of Computer Network Technology, the research and development of the distributed RSM is being paid more attention.There are two key issues to be solved in the design of a distributed Resource Space Model System (RSM): the design of resource space fragmentation and the allocation of the location of resource space fragmentation. The fragmentation is a process which can partition a global resource space into several resource space fragmentations; the allocation is a process which can map several resource space fragmentations to one or several sites. Taking the two key issues mentioned above and the characters of distribution, this thesis presents the design of resource space fragmentation, the allocation of the location of resource space fragmentation and theapplication of which in a study case------The Paper Searching System. The maincontributions of the thesis include: (1) presents the goals for resource space fragmentation; (2) proposes three fundamental fragmentation strategies: coordinate-based resource space fragmentation,axis-based resource space fragmentation and hybrid resource space fragmentation; (3) and proposes rules to guarantee the correctness of resource space fragmentation: completeness condition,reconstruction condition and disjoin condition; (4) presents the differences of fragmentation between DRSM and DDBS; (5) analyses the demand of resource distribution and design the distribution of resource space fragmentation, so that we can validate the availability of fragmentation and the reasonableness of allocation.