User-assisted tools for concurrency control in distributed multimedia collaborations

Abstract

In a distributed collaborative application, a key requirement is that all users see the same copy of a shared window object at any given point in time (WYSIWIS). In this paper, we study 'userassisted causal ordering' of messages as the basis for achieving WYSIWIS. The approach requires specifying the synchronization constraints on accessing shared window objects in the form of an order in which messages need to be processed and object state updated. The specifications are made available to the window subsystem based on the user-level knowledge about the actions on objects and the current (shared) object state. In contrast with the current approaches employing transaction models, our approach allows flexibility in the programming of collaboration-style applications, and offers increased levels of concurrency.

A Context-Driven Framework for Distributed Collaboration

“…Assuring that during the period over which user actions are generated, no actions are executed, we can keep the global state unchanged. In this light, our earlier work [7] focused on a causality-oriented view of the collaboration problem.…”

Survey of computer-supported collaboration in support of business processes

“…The necessity of concurrency control originally arose from managing shared resources among simultaneously running threads in operating systems (Silberschatz and Galvin, 1998). In the CSCW realm, concurrency control focuses on the management of parallel threads of HCIs that involve potential conflicts (Russel et al, 1996;Sabbir and Ravindran, 2004). Concurrency control ensures that multiple threads of related collaboration work can be incorporated in one integrated CSCW environment.…”

“…Concurrency control ensures that multiple threads of related collaboration work can be incorporated in one integrated CSCW environment. In addition, in synchronous cooperative work, when different users share a common object, concurrency control is compulsory to maintain the shared object consistent (Sabbir and Ravindran, 2004). In more detail, each collaborator should see the exact same sequence of actions to be performed on the shared artefact.…”

“…In addition, CovaTM (Jiang et al, 2002) presented a comprehensive transaction model to support collaboration work, where user intervention is explicitly introduced. Sabbir and Ravindran (2004) suggested that a temporal relationship should be bound to data segments. Currently, most of the work in this direction derives from concurrency control research in distributed systems.…”