Research

Interests

• My general area of expertise is in Systems and Control Engineering.
• I am a member of the Control Systems Research Area in the EECS Department and of the Controls Group in the College of Engineering at the University of Michigan.
• I am also a member of Michigan Robotics.
• My research interests are in Discrete Event Systems (DES), including modeling, analysis, supervisory control, optimal control, and diagnosis of this class of dynamical systems. I am also working on applications of DES in computer and communication systems and in software systems. For further information about Discrete Event Systems, you may consult the textbook Christos Cassandras and I co-authored, Introduction to Discrete Event Systems, or the following websites:
  – IEEE Technical Committee on Discrete Event Systems
  – IFAC Technical Committee on Discrete Event and Hybrid Systems

Projects

Current Projects

• Cyber-secure and Resilient Supervisory Control of Networked Discrete-Event Systems
  Ongoing project with Wayne State University.
• Communication-Obfuscation Project
  The Communication-Obfuscation Project refers to our work on the information flow property called opacity and its enforcement by the technique of insertion/edit functions, whose objective is to obfuscate the output of a system to enforce opacity.

• DES Cybersecurity Project
  This project is studying cyber and cyber-physical control systems subject to attacks that compromise their sensors and/or their actuators.

Recent Past Projects

• Protocol Design and Implementation The goal of this project is to bridge the gap between an abstract protocol design and a low-level implementation through a novel combination of security modeling, automated software synthesis, and program analysis. This is a joint project with Daniel Jackson, Eunsuk Kang, Cristina Nita-Rotaru, and Stavros Tripakis.

• CPS_Energy: Energy-Aware Formal Synthesis for Supervisory Control and Information Acquisition in Cyber-Physical Systems This project is developing theoretical foundations and computational algorithms for synthesizing higher-level supervisory and information-acquisition control logic in cyber-physical systems that expend or replenish their resources while interacting with the environment.

• Control and Diagnosis of Safety-Critical Complex Cyber-Physical Systems This NSF CPS project developed novel architectures for control and diagnosis of complex cyber-physical systems subject to stringent performance requirements in terms of safety, resilience, and adaptivity. This was a joint project with my colleague Necmiye Ozay.
• CPS_Security: Intrusion Detection and Resilience Against Attacks in Cyber and Cyber-Physical Control Systems This project investigated of a novel methodology for analyzing and designing secure cyber and cyber-physical systems that contain feedback control loops and that interact with their environment through a set of potentially vulnerable sensors and actuators.
• TerraSwarm Project The TerraSwarm Research Center, funded by the STARnet Program. In this project, I was interested in security and privacy issues in cyber-physical systems.
• ExCAPE Project Expeditions in Computer Aided Program Engineering. This project, funded by NSF, was a collaborative effort involving 18 researchers from 9 academic institutions. In this project, I was particularly interested in applying control synthesis techniques from the field of discrete event systems to the general problem of program synthesis. I was co-lead of the Education and Knowledge Transfer thrust and member of the Executive Committee of this Expedition’s grant.
• Gadara Project Deadlock avoidance in concurrent software using discrete control theory. This project was funded by NSF and HP Labs from 2008-2012.
• Cyber-Physical Systems Project Control of distributed cyber-physical systems under partial information and limited communication. This project was funded by NSF from 2009-2013.
• Modular Strategies for Internetwork Monitoring Project Detection and classification of spatially distributed network anomalies. This project, directed by Alfred Hero, was funded by NSF from 2003-2010.
• Distributed and Fault-Tolerant Control of Discrete-Event Systems This project was funded by NSF from 2006-2010. Our main results include:
  (i) modular algorithms for controller synthesis that exploit structural properties of the system, expressed as parallel composition of automata or place-bordered Petri nets, and abstraction;
  (ii) fault-tolerant diagnosis and control architectures that are robust to certain classes of system faults, sensor faults, and diagnosis module faults; and
  (iii) efficient synthesis of sensor activation and communication strategies for control and diagnosis of distributed systems.

Please also consult the UMDES Wiki and DESUMA Wiki for further information about my research activities.