Research And Application Of Concurrency Control In CSCW

With the development of computer technology, network technology and distributed technology, computer user's working pattern has developed from single user working pattern to multi-user working pattern. Computer Supported Cooperative Work (CSCW) came into being under this background and it has reflected the colony, interaction, distribution and cooperation of people's working mode in the information era. However, when different users manipulate the same sharing object, the conflict will occur inevitably. So, in a sharing multi-user environment, in order to avoid inconsistency, increase efficiency, guarantee the successful cooperation, it is important to coordinate the actions of collaborative users.This paper explores concurrency control in CSCW after summarizing and referring domestic and overseas research achievement about CSCW and proposes several feasible new methods. Main research aspects and creative achievements are as follows:①Concurrency control theory on the basis of group management in LAN (Local Area Network). General speaking, users in CSCW environment locate in the LANs, which has high bandwidth, high transmission speed and reliability. These LANs connect to the wide area network through access network, so as to let different users work together. Access network may become the bottleneck of the whole network, because of its low-bandwidth and reliability comparing with the LAN. So we propose a concurrency control theory on the basis of group management in LAN. Its basic idea is to set a management node, which is responsible for the concurrent control in LAN and can improve the efficiency of concurrency control.②Adaptive concurrency control framework. Aiming at resolving the deficiency of pessimistic and optimistic concurrency control strategies in comparison with them, this paper proposes an adaptive concurrency control policy and presents a basic design and primary implementation. The basic idea of the concurrency control policy is to mix the pessimistic and optimistic concurrency control strategies in the same system, which can adjust the concurrency control strategies automatically according to the actual situation. In this way, the contradiction between pessimistic and optimistic concurrency control can be resolved efficiently and we have also proved the validity through an experiment.The adaptive concurrency control framework is on the basis of adaptive concurrency control strategy, and combines with the theory of group management in LAN. This framework can efficiently resolve the concurrency control in collaborative system and balance the consistency and responsiveness well.Finally, this paper designs a prototype system, which proves that the adaptive concurrency control framework is correct and effective.