Patent US 5,503,249

A system and method for controlling an elevator group including several elevators and related call devices which controls each elevator in a manner determined by the calls entered and the existing control instructions. When the control system has to decide between two or more control alternatives, a systematic decision analysis is performed by studying the effects resulting from each alternative decision, the effects resulting from each alternative decision, the effects being estimated by simulating by a Monte-Carlo type method the future behavior of the elevator system in the case of each alternative decision. To carry out the simulation, realizations are generated at random for the unknown quantities associated with the current state of the elevator system and for new external future events, and a control decision is made on the basis of the results of the decision analysis.