I am employed by QSS and conduct research within the Robust Software Engineering group in the Intelligent Systems Division at NASA Ames. I obtained an M.Sc. and Ph.D. from the ECE Department at The University of Texas at Austin.

In my dissertation, I define a (max,+) algebra for non-stationary and periodic discrete event systems (i.e., delays are not necessarily constant over time). This algebra can be used to verify timing behaviors and synthesize controllers. Details about on-going research on (max,+), and other exotic algebras, can be found on the MaxPlus web page maintained by Stephane Gaubert.

My main research interest is in static analysis of programs. With Arnaud Venet, we designed a static analyzer for C programs called C Global Surveyor. CGS has already been applied to the flight software of several NASA missions such as Mars PathFinder and Deep Space One. I am currently using it to analyze the flight software of the Mars Exploration Rover mission. We are also starting another project that will analyze a restrictive subset of (C++) for the future Mars Science Laboratory mission. Stay tune...

I also used to explore how static analysis can be applied to alleviate the state explosion problem when model checking Java programs using Java PathFinder. We pursued three research directions:

• executable program slicing
• safe block analysis (to perform partial order evluation)
• interactions between static analyzers and model checkers

• G. Brat and R. Klemm, Static Analysis of the Mars Exploration Rover Flight Software. In Proceedings of the First International Space Mission Challenges for Information Technology, Pasadena, California, July 2003.
  
• G. Brat, A (max,+) Algebra for Non-Stationary and Non-Deterministic Periodic Discrete Event Systems. PhD Dissertation, The University of Texas at Austin, December 1998.
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• G.P. Brat and V.K. Garg, Analyzing Non-Deterministic Real-Time Systems with (max,+) Algebra,. In Proceedings of the 19th IEEE Real-Time Systems Symposium, Madrid, Spain, December 1998.
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• G.P. Brat and V.K. Garg, A (max,+) Algebra for Periodic Timed Discrete Event Systems,. In proceedings of the 4th International Workshop on Discrete Event Systems , pages 237-242, Cagliari, Italy, August 1998.
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• G.P. Brat and V. K. Garg, A (max,+) Algebra of Signals for the Supervisory Control of Real-Time Discrete Event Systems,. In proceedings of the 9th IFAC Symposium on Information Control in Manufacturing (INCOM'98), pages 9-14, Nancy-Metz, France, June 1998.
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• M. Breland, S. Rogers, G.P. Brat, and K. Nelson, Transparent Fault Tolerance for Distributed Ada Applications,. In Proceedings of the TRI-Ada '94 Conference, pages 446-458, Baltimore, Maryland, November 1994.