Abstract
Scheduling rules for asynchronous, concurrent systems are constructed based on a systematic analysis of tasks given to the systems. First, it is assumed that the tasks can be represented as propositions such as “to attain the goal state” or “to maintain the system in normal states” etc., which inevitably include the notion of time (tense) such as “in the future”, “at the next time” etc. Then, based on the general framework called “tense logic” dealing with the qualitative properties of time such as transitivity, discreteness and linearity, each proposition representing the task is transformed into a kind of transition diagram which indicates the action necessary to be done at each time instant. Incorporating it with the Petri net representation of the systems, the scheduling rules are constructed in a systematic way, i.e., the firing of transitions in the Petri nets necessary to be prohibited is clarified.
