Home > Colloquia > Monday, March 29, 2010

Model Checking is an automatic verification technique for state-transition systems that are finite-state or that have finite-state abstractions.  In the early 1980’s in a series of joint papers with my graduate students E.A. Emerson and A.P. Sistla, we proposed that Model Checking could be used for verifying concurrent systems and gave algorithms for this purpose.  At roughly the same time, Joseph Sifakis and his student J.P. Queille at the University of Grenoble independently developed a similar technique.  Model Checking has been used successfully to reason about computer hardware and communication protocols and is beginning to be used for verifying computer software.  Specifications are written in temporal logic, which is particularly valuable for expressing concurrency properties.  An intelligent, exhaustive search is used to determine if the specification is true or not. If the specification is not true, the Model Checker will produce a counterexample execution trace that shows why the specification does not hold. This feature is extremely useful for finding obscure errors in complex systems. The main disadvantage of Model Checking is the state-explosion problem, which can occur if the system under verification has many processes or complex data structures. Although the state-explosion problem is inevitable in worst case, over the past 27 years considerable progress has been made on the problem for certain classes of state-transition systems that occur often in practice. In this talk, I will describe what Model Checking is, how it works, and the main techniques that have been developed for combating the state explosion problem.

Biography:

Edmund M. Clarke received a B.A. degree in mathematics from the University of Virginia, Charlottesville, VA, in
1967, an M.A. degree in mathematics from Duke University, Durham NC, in 1968, and a Ph.D. degree in Computer
Science from Cornell University, Ithaca NY, in 1976. After receiving his Ph.D., he taught in the Department of
Computer Science, Duke University, for two years. In 1978 he moved to Harvard University, Cambridge, MA where he
was an Assistant Professor of Computer Science in the Division of Applied Sciences. He left Harvard in 1982 to join
the faculty in the Computer Science Department at Carnegie-Mellon University, Pittsburgh, PA. He was appointed Full
Professor in 1989. In 1995 he became the first recipient of the FORE Systems Professorship, an endowed chair in the
School of Computer Science. He was named a University Professor in 2008.
Dr. Clarke's interests include software and hardware verification and automatic theorem proving. In his Ph.D. thesis he
proved that certain programming language control structures did not have good Hoare style proof systems. In 1981 he
and his Ph.D. student Allen Emerson first proposed the use ofModel Checking as a verification technique for finite
state concurrent systems. His research group pioneered the use of Model Checking for hardware verification. Symbolic
Model Checking using BDDs was also developed by his group. This important technique was the subject of Kenneth
McMillan's Ph.D. thesis, which received an ACM Doctoral Dissertation Award. In addition, his research group
developed the first parallel resolution theorem prover (Parthenon) and the first theorem prover to be based on a
symbolic computation system (Analytica).
Dr. Clarke has served on the editorial boards of Distributed Computing, Logic and Computation, and IEEE
Transactions in Software Engineering. He is the former editor-in-chief of Formal Methods in Systems Design. He is on
the organizing committee of Logic in Computer Science (LICS) and on the steering committee of Computer-Aided
Verification (CAV). He received a Technical Excellence Award from the Semiconductor Research Corporation in
1995. He was a co-winner with Randy Bryant, Allen Emerson, and Kenneth McMillan of the ACM Kanellakis
Award in 1998 for the development of Symbolic Model Checking. In 1999 he received an Allen Newell Award for
Excellence in Research from the Carnegie Mellon Computer Science Department. In 2004 he received the IEEE
Harry H. Goode Memorial Award for significant and pioneering contributions to formal verification of hardware and
software systems, and for the profound impact these contributions have had on the electronics industry. He was elected
to the National Academy of Engineering in 2005 for contributions to the formal verification of hardware and software
correctness. He was a recipient with Allen Emerson and Joseph Sifakis of the 2007 ACM Turing Award for his role
in developingModel Checking into a highly effective verification technology, widely adopted in the hardware and
software industries. In 2008 he received the CADE Herbrand Award for Distinguished Contributions to Automated
Reasoning in recognition of his role in the invention of Model Checking and his sustained leadership in the area for
more than two decades. Dr. Clarke is a Fellow of the ACM and the IEEE, and a member of Sigma Xi and Phi Beta
Kappa.