Towards a General Solution of System Automation: A Net Specification of an N-LiftSystem

摘要

Changes in a system are characterized by their extensions in net theory. In thisway, concurrency, conflict and other fundamental phenomena can be described rather naturally. The purpose of the paper is not only to introduce a new model for the lift-(Elevator) problem, but also to explore the advantage of Petri nets in system specification, which are, to some extent, obscured in some existing net specifications for lifts. In this way, insights into a general solution of system automation are brought out. As is shown in the paper, net theory allows one to concentrate on individual changes and when these changes are related to each other via their extensions, the system structure is completed. Thus, a straightforward problem like n lift system is solved in a straightforward way. It turns out that a net specification of N lifts is just as simple as that of a single lift. Besides, it leaves room for optimization during implementation by allowing as much concurrency and nondeterminism as possible. The lift problem is but a concrete example of system automation. The principles and the advantages of net models exibited by this example are not confined here. (Copyright (c) GMD 1990.)