Research

My masters research all about modeling and simulation of individual-based (you can also call it, multi-agent) hybrid systems. There already exists a research group at the University of Pennsylvania which has developed a multi-agent hybrid system modeling and simulation environment called CHARON. However, my research is not about modeling and simulating arbitrary hybrid systems but those that are physically meaningful. This is where the notion of energy comes in. Bond-graphs are a 50 year old formalism introduced by H.M. Paynter and established by many other scientists like Francois Cellier, Dean Karnopp, Peter C. Breeveld, Jan Broenink and several others. The laws of physics like conservation of energy, continuity of power etc. are heralded by this formalism. Dr. Pieter J. Mosterman has used bond graphs to model physically meaningful hybrid systems by correctly re-initializing the system state after the transition from one continuous mode to another. The beauty of bond graphs is its ability to give considerable insight into the actual working of the physical system. So, where does all this culminate? The goal is the following...

To develop formal syntax and "semantics" and a programming(or modeling) and simulation environment for an individual based modeling and simulation system that incorporates the power of bond graphs. We see the applicability of this approach in many domains including nano-science, biology, MEMS etc. This system will finally be meta-modelled and incorporated into AToM3.

The inverse problem of mapping global behaviour to local behaviour is also of great interest to me. Gaining insight of moving from the macroscopic world to the microscopic world and vice versa is considered to be a grand challenge problem that touches every known branch of science and technology. If time permits our approach will be to observe how energetics at the macro-level boil down as constraints to the energy exchange at the micro-level and vice versa. :-)

Presently I am working on building Entity-Relationship based meta-models for acausal and causal bond graphs and transforming them into various standard simulatable/exchange forms (Modelica code, ODEs, DAEs) using graph grammars and graph algorithms.

Presentations

March 09, 2005, Bond Graphs: A Formalism For Modeling Physical Systems, Sagar Sen [PPT]
April 06, 2005, Bond Graphs in AToM3, Sagar Sen [PPT]

Maintained by Sagar Sen .

Last Modified: 2008/09/10 00:03:05.