Arbeitspapiere der GMD Nr. 439, pages 1-30 pp.. St. Augustin: Gesellschaft für Mathematik und Datenverarbeitung mbH, March 1990.
Abstract: The purpose of this paper is not only to introduce a new model for the lift 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. As one can see, net theory allows to concentrate on individual changes and when this changes are related to each other via their extensions, the system structure is completed. Thus the problem of an 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.
Keywords: system automation; specification (of a) lift system.