Synthesis of distributed control through knowledge accumulation

In distributed systems, local controllers often need to impose global guarantees. A solution that will not impose additional synchronization may not be feasible due to the lack of ability of one process to know the current situation at another. On the other hand, a completely centralized solution will eliminate all concurrency. A good solution is usually a compromise between these extremes, where synchronization is allowed for in principle, but avoided whenever possible. In a quest for practicable solutions to the distributed control problem, one can constrain the executions of a system based on the pre-calculation of knowledge properties and allow for temporary interprocess synchronization in order to combine the knowledge needed to control the system. This type of control, however, may incur a heavy communication overhead. We introduce the use of simple supervisor processes that accumulate information about processes until sufficient knowledge is collected to allow for safe progression. We combine the knowledge approach with a game theoretic search that prevents progressing to states from which there is no way to guarantee the imposed constraints.