jr.sagepub.com/cgi/content/abstract/26/6/607 The online version of this article can be found at: Published by: http://www.sagepublications.com On behalf of: Multimedia Archives can be found at:The International Journal of Robotics ResearchAdditional services and information for http://ijr.sagepub.com/cgi/alertsEmail Alerts: http://ijr.sagepub.com/subscriptionsSubscriptions: http://www.sagepub.com/journalsReprints.navReprints: http://www.sagepub.com/journalsPermissions.navPermissions: © 2007 SAGE Publications. All rights reserved. Not for commercial use or unauthorized distribution. at Brunel University on June 24, 2008http://ijr.sagepub.comDownloaded from