Departmental Papers (MEAM)

Document Type

Journal Article

Subject Area


Date of this Version

March 2007


Copyright 2007 IEEE. Reprinted from IEEE Transactions on Robotics and Automation Magazine, Volume 14, Issue 1, March 2007, pages 9-10.

This material is posted here with permission of the IEEE. Such permission of the IEEE does not in any way imply IEEE endorsement of any of the University of Pennsylvania's products or services. Internal or personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution must be obtained from the IEEE by writing to By choosing to view this document, you agree to all provisions of the copyright laws protecting it.



Date Posted: 24 April 2007

This document has been peer reviewed.