Collaborative systems provide a rich but potentially chaotic environment for their users. This paper presents a system that allows users to control collaboration by enacting policies that serve as general guidelines to restrict and define the behavior of the system in reaction to the state of the world. Policies are described in terms of access control rights on data objects, and are assigned to groups of users called roles. Roles represent not only statically-defined collections of users, but also dynamic descriptions of users that are evaluated as applications are run. This run-time aspect of roles allows them to react flexibly to the dynamism inherent in collaboration. We present a specification language for describing roles and policies, as well as a number of common "real-world" policies that can be applied to collaborative settings.

Asynchronous collaboration is characterized by the degree of independence collaborators have from one another. In particular, collaborators working asynchronously typically have little need for frequent and fine-grained coordination with one another, and typically do not need to be notified immediately of changes made by others to any shared artifacts they are working with. We present an infrastructure, called Bayou, designed to support the construction of asynchronous collaborative applications. Bayou provides a replicated, weakly-consistent, data storage engine to application writers. The system supports a number of mechanisms for leveraging application semantics; using these mechanisms, applications can implement complex conflict detection and resolution policies, and choose the level of consistency and stability they will see in their databases. We present a number of applications we have built or are building using the Bayou system, and examine how these take advantage of the Bayo...

models of information sharing, and runtime support based on those models, are by themselves incomplete for the task of constructing robust, practical collaborative applications. To be usable, we must provide a means for developers to access these facilities easily. This chapter has presented developer perspectives on the concepts introduced by Intermezzo. We have investigated a number of components of the developer support, or "toolkit," in this research, including notification, programming interfaces for accessing shared data, interfaces for accessing collaboration-specific functionality, and the use of scripting through embedded computation. Notification is one of the most important problems to be addressed in any developer support: how do applications (and, by extension, their users) become aware of changes in their environments? This problems is especially vexing in the case of coordination, where information that may be considered interesting is plentiful, change is rapid, and the...

. Nowadays, the design of cooperative applications is becoming more complex due to the introduction of real time cooperation and multimedia aspects. To ease and accelerate the development of these applications it is necessary to build modular and reusable functional components that can be used by application designers. The objective of this paper is to define some of those functional components. They will be integrated in the cooperative applications to ensure the synchronous cooperation on multimedia objects. For openness and possible wide use in an open distributed heterogeneous environment, the specification of those components is based on the computational language of the Reference Model of Open Distributed Processing (RMODP) . Keywords. Multimedia cooperative applications, CSCW, Open Distributed Processing, ODP, Distributed Multimedia Application Architecture. 1 Introduction The fast advancement of computer technology and its decreasing price enable the use of high...

A new class of systems that should appear in a next future should enable several users to lead synchronous cooperative activity by way of their computing systems. These cooperative systems should be able to operate in heterogeneous environments involved by the operating and communication environment of the user. In order to build such cooperative system it is needed to have open cooperative systems based de jure standards such as Open Distributed Processing Reference Model (ISO/ODP-RM) and on de facto standards such as OMG/CORBA. To answer this need, this paper summarises a complete analyse of open distributed cooperative systems based on standards and presents a set of open management services common to cooperative systems. Together, these services, generic enough to be reusable, build a middleware layer which, once inserted between now emerging distributed platforms and end-user applications, will enable participants to keep their favourite applications and to continue to use them ...

Existing enterprise calendaring systems have suffered from problems like rigidity, lack of transparency, and poor integration with social networks. We present the system design and rationale for a novel social coordination mechanism, called “Suggestions,” that addresses these issues. Our system integrates ideas drawn from designs of lightweight polling systems and one’s social network into an open calendar tool, providing a space for users to coordinate, socialize around, or negotiate the “what ” and the “when ” of their events. Suggestions was released inside a large enterprise setting, where initial interviews revealed users’ thoughts on transparent scheduling, reaching wider audiences and task appropriateness, and suggested ways to improve our design. Categories and Subject Descriptors H.5.m. Information interfaces and presentation (e.g., HCI):