Defining task interdependencies and coordination mechanisms for collaborative systems

This paper addresses the issue of coordination, which is an essential matter to the specification of activities in collaborative systems. An activity can be described as a set of interdependent tasks. In order to specify task interdependencies, an extensible model encompassing a set of temporal and resource management relations is initially presented. Then, Petri Nets are used to formally model coordination mechanisms for those interdependencies. The separation between tasks and interdependencies/coordination mechanisms allows for the deployment of different coordination policies in the same collaborative system by only changing the coordination mechanisms. Moreover, the coordination mechanisms, like the related interdependencies, are generic and may be reused in several collaborative systems.