Free Schedules for Free Agents in Work ow Systems Areas: time in multiple agents, communication, and synchronization; temporal constraint reasoning

This paper investigates work ow systems in which the enactment and completion of activities have to satisfy a set of quantitative temporal constraints. Di erent activities are usually performed by autonomous agents, and the scheduling of activities by the enactment service has among its goals the minimization of communication and synchronization among the agents. The paper formally denes the notion of a schedule for these work ow systems and it identi es a particularly useful class: free schedules. A schedule speci es a time range for the enactment, duration, and completion of each activity in order to satisfy all the temporal constraints in the work ow. In a free schedule, an agent has to start its activity within the range speci ed in the schedule, but it is free to use any amount of time to nish the activity as long as it is between a minimum and maximum time he has declared when the work ow is designed. No synchronization with other agents is needed. The paper provides a method to characterize all the free-schedules admitted by a work ow speci cation, and an algorithm to derive them.