PORTS and TERMINALS   . . . Abstract & Biography Jan Willems, K.U. Leuven, Belgium     4:15 PM, Stata Center, Room 32-141 LIDS Colloquium -   There will be a short reception at 5:30 p.m. on the 6th floor of the Dreyfoos Tower

Abstract & Biography

Abstract: This lecture has a ‘back to basics’ flavor. We examine what is meant by the power and the energy which an open system exchanges with its environment. The systems which we consider interact through terminals, as wires in the case of electrical circuits, and pins for mechanical systems. Systems are interconnected by sharing terminal variables. We define a port as a set of terminals that satisfy port-KVL and port-KCL. The usual expressions for power and energy are not valid unless the terminals involved form a port. We also discuss the nature of ports for mechanical systems, and derive an expression for kinetic energy that is not frame dependent. We conclude that terminals are for interconnection, and ports are for energy transfer. Interconnection is local, while power and energy involve action at a distance. We end by formulating a conjecture that states that a connected RLC circuit forms a 1-port.

Biography: Jan Willems was born in Bruges, and received engineering degrees from the University of Gent and the University of Rhode Island. He got his Ph.D. degree from MIT in 1968, and was an assistant professor of electrical engineering at MIT until 1973. He was professor of Systems and Control in the Mathematics Department of the University of Groningen from 1973 until 2003. Presently he is professor at the K.U. Leuven. More details and a list of publications may be found at http://www.esat.kuleuven.be/_jwillems.