Risk-Averse Group Elevator Scheduling

We introduce a novel group elevator scheduler based on an explicit decision-theoretic calculation for the expectation of any polynomial function of passengers’ waiting times, marginalized over sources of uncertainty in the system state. The same framework can be used to identify risky assignments that have low expected costs but may cause some individuals to be ”stranded” with excessive waits for service. The resulting scheduler avoids risky assignments while minimizing average passenger waits. Experimental results demonstrate that the method can reduce the variance of waiting times and the fraction of passengers waiting excessively in comparison with risk-neutral schedulers, while still achieving better waiting times than reference ETA controllers. This paper has been presented at the 14th International Congress on Vertical Transportation Technologies, April 27-29, 2004, Istanbul, Turkey. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. Copyright c ©Mitsubishi Electric Research Laboratories, Inc., 2004 201 Broadway, Cambridge, Massachusetts 02139