报告人：Christos G. Cassandras (Boston University)
A unifying optimization framework will be presented which encompasses most commonly encountered static and dynamic cooperative multi-agent system problems, including coverage control, consensus, formation control, and persistent monitoring. One of the main challenges in this framework is ensuring that the problems can be solved through distributed algorithms where each agent requires only local information from an appropriately defined neighborhood. Another challenge arises from the fact that most interesting problems involve nonconvex objective functions allowing common gradientbased distributed algorithms to be trapped in poorly preforming local optima.
We first address the fundamental question “when can a multi-agent problem be decentralized?” in the sense that an optimal solution can be fully recovered through a distributed optimization scheme. We will show that this is possible for a large class of problems, while for others we can only achieve this in an “almost distributed” manner.
We next describe a systematic method for escaping a local optimum by exploiting the structure of the objective function and knowledge of an agent’s neighborhood rather than by randomly perturbing controllable variables away from it. This is accomplished through boosting functions applied as transforms of the objective function gradient at an equilibrium point in a way that induces a search for a new equilibrium point. We will show how convergence can be attained through a distributed optimization algorithm with optimally selected step sizes. Examples will be included showing how to improve solutions of some particularly difficult non-convex multi-agent problems.
Christos G. Cassandras is Distinguished Professor of Engineering at Boston University. He is Head of the Division of Systems Engineering, Professor of Electrical and Computer Engineering, and co-founder of Boston University’s Center for Information and Systems Engineering (CISE). He received a B.S. degree from Yale University, M.S.E.E from Stanford University, and S.M. and Ph.D. degrees from Harvard University. In 1982-84 he was with ITP Boston, Inc. where he worked on the design of automated manufacturing systems. In 1984-1996 he was a faculty member at the Department of Electrical and Computer Engineering, University of Massachusetts/Amherst. He specializes in the areas of discrete event and hybrid systems, cooperative control, stochastic optimization, and computer simulation, with applications to computer and sensor networks, manufacturing systems, and transportation systems. He has published over 400 refereed papers in these areas, and six books. He has guest-edited several technical journal issues and serves on several journal Editorial Boards. In addition to his academic activities, he has worked extensively with industrial organizations on various systems integration projects and the development of decision-support software. He has most recently collaborated with MathWorks, Inc. in the development of the discrete event and hybrid system simulator SimEvents.
Dr. Cassandras was Editor-in-Chief of the IEEE Transactions on Automatic Control from 1998 through 2009 and has also served as Editor for Technical Notes and Correspondence and Associate Editor. He is currently an Editor of Automatica. He was the 2012 President of the IEEE Control Systems Society (CSS). He has also served as Vice President for Publications and on the Board of Governors of the CSS, as well as on several IEEE committees, and has chaired several conferences. He has been a plenary/keynote speaker at numerous international conferences, including the American Control Conference in 2001, the IEEE Conference on Decision and Control in 2002 and 2016, and the 20th IFAC World Congress in 2017 and has also been an IEEE Distinguished Lecturer.
He is the recipient of several awards, including the 2011 IEEE Control Systems Technology Award, the Distinguished Member Award of the IEEE Control Systems Society (2006), the 1999 Harold Chestnut Prize (IFAC Best Control Engineering Textbook) for Discrete Event Systems: Modeling and Performance Analysis, a 2011 prize and a 2014 prize for the IBM/IEEE Smarter Planet Challenge competition (for a “Smart Parking” system and for the analytical engine of the Street Bump system respectively), the 2014 Engineering Distinguished Scholar Award at Boston University, several honorary professorships, a 1991 Lilly Fellowship and a 2012 Kern Fellowship. He is a member of Phi Beta Kappa and Tau Beta Pi. He is also a Fellow of the IEEE and a Fellow of the IFAC.