Synchronization Of Heterogeneous Distributed Environment Collaborative Cad System

Computer-Supported Cooperative Design (CSCD) is an efficient application of the conceptions and techniques about Computer-Supported Cooperative Work (CSCW) in the product development procedure in manufacture. On account of the historical reason, among commercial systems of CAD software at present there are some problems about differences between their internal data structures, their functions and so on. Therefore, it is one of key techniques in the CSCD system discussed in this paper to resolve the mutual operation among CAD systems with different mechanisms. In addition, its techniques in the CSCD system are also discussed since the strategies of concurrent control are very critical in CSCW systems.Firstly, this paper analyzes some currently relative techniques of systematic architectures, the process of information in various CAD systems with different mechanisms, consistence maintenance, consistency avoidance and the like, in current CSCD systems. At the same time, these representative control strategies about these relative techniques explored by other researchers are also researched carefully.Secondly, this paper gives concrete strategies for a synchronous and cooperative CAD system—CoCADClient(abbreviated as a prototype system as follows), which are about systematic architecture, the process of information with different structures, consistency avoidance and the like. According to current existed control strategies, these strategies proposed in this paper and based on the principle of practical applications are proper for being applied in it after the prototype system is researched. (1) the prototype system uses a semi-replicated architecture. (2) this paper gives a novel exchange standard of information in various CAD systems with different mechanisms, and a new transistion protocol based on the object's information that is only relative to the operation, by analyzing and researching current controlling techniques of information in various CAD systems, and studying various CAD systems and their respective tools of their second development tools. (3)as for the concurrent control techniques the prototype system implements the method of pessimistic locking with accordance to the features of the graphic objects that CAD systems operate on.Finally, as for CoCADClient that is the implementation of the prototype system, this paper validates the correctness of the proposed strategies and algorithms from the perspective of systematic implementation. Other related cooperative techniques used in this prototype, as well as its runtime performance, are also discussed briefly in the end of this paper.