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Collaboration in a nutshell

Collaborative software (also referred to as groupware, workgroup support system or simply group support system) is computer software desighed to help people involved in a common task achieve their goals. It is usually associated with individuals not physically co-located, but instead working together across an internet connection. It can also include remote access storage systems for archiving common use data files that can be accessed, modified and retrieved by the distributed workgroup members (more details can be found here).


Welcome to collaborative tools web page, designed by Cassis Team and allowing for distributed collaborative applications.

It is khown that concurrent modifications done on a shared document may lead to divergence cases. The convergence is ensured thanks to OPTIC allowing for completly decentralised collaboration.

Realized Tools

The realized tools allows for:


Convergence is achieved thanks to OPTIC allowing for completly decentralised collaboration. Indeed, it meets the following requirements:

  • High local responsiveness: the system is as responsive as a single-user editor
  • High concurrency: the users are able to concurrently and freely modify any part of the shared document at any time
  • Consistency: the users mare able to see a converged view of all copies
  • Decentralized coordination: all concurrent updates are synchronized in decentralized fashion in order to avoid a single point of failure
  • Scalability: users may join or leave the group at any time

Access Control

Access control is very important in the sense that it allows the definition of access rules in order to protect shared data. However defining access control rules in a decentralized fashion is a challanging problem. We propose an optimistic access control based on replicating the access control policy. This issue was discussed in the paper "A Flexible Access Control Model for Distributed Collaborative Editors"

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