Research And Implementation On Concurrency Control In CSCW-based Doctor CAD System

In this modern society, as global competition goes fiercer and fiercer, design, manufacturing and market of product are facing extreme challenge. Traditional serial design method can not face the need of continuously fast-changing market. Enterprises should make good use of information technology based on networks to promote their competitive strength with new designing and manufacturing mode. In this way, they can assemble scattered design resources quickly and, as a result, form a teamwork-collaborative design mode based on networks within the enterprise or between several enterprises. As the information process proceeds, computer supported collaborative work gets more and more attention and becomes a hot research area.This dissertation discusses on how to make use of computer and its related technologies to support teamwork and to implement a CSCW-based collaborative Dr. CAD system. Most important of all, concurrency control mechanism and access control mechanism are deeply discussed in detail.The whole design target of the system is proposed firstly. Collaborative design feature and collaborative method are analyzed and architectures of collaborative system are compared and the architecture of collaborative Dr. CAD system is described.The dissertation makes analysis and discussion of concurrency control method of currently available CSCW system and proposes the concurrent control principle and consistent model of collaborative Dr. CAD system.Furthermore, the paper proposes a new access control mechanism of Dr. CAD system called BSRBAC based on both RBAC in the initial version of Dr. CAD and SRBAC in the second version of Dr. CAD system. Theoretically, the new access control model can solve the problems occurred in previous versions of Dr. CAD system.Finally, the concurrency control and access control proposed in this dissertation are implemented in the Dr. CAD system.The experiment has proved that the Dr. CAD system has the open style structure and has effectively verified the related technology proposed in this paper. Dr. CAD has high responsiveness, concurrency and dynamic compatibility, and can carry on conflict processing effectively.