Consistency control for synchronous and asynchronous collaboration based on shared objects and activities. Computer Supported Cooperative Work

Abstract. We describe a new collaborative technology that bridges the gap between ad hoc collaboration in email and more formal collaboration in structured shared workspaces. Our approach is based on the notion of object-centric sharing, where users collaborate in a lightweight manner but aggregate and organize different types of shared artifacts into semi-structured activities with dynamic membership, hierarchical object relationships, as well as real-time and asynchronous collaboration. We present a working prototype that implements object-centric sharing on the basis of a replicated peer-to-peer architecture. In order to keep replicated data consistent in such a dynamic environment with blended synchronous and asynchronous collaboration, we designed appropriate consistency control algorithms, which we describe in detail. The performance of our approach is demonstrated by means of simu-lation results