Tech Talk: Testing First-Order-Logic Axioms in AutoCert

  • Date  Time
  • Speaker
  • Location

The November 3rd Galois Tech Talk will be delivered by Ki Yung Ahn, titled “Testing First-Order-Logic Axioms in AutoCert.”

  • Date: Tuesday, November 3rd, 2009
  • Time: 10:30am – 11:30am
  • Location: Galois, Inc.421 SW 6th Ave. Suite 300(3rd floor of the Commonwealth Building)Portland, OR 97204

Abstract: AutoCert is a formal verification tool for machine generated code in safety critical domains, such as aerospace control code generated from MathWorks Real-Time Workshop.  AutoCert uses Automated Theorem Proving (ATP) systems based on First-Order-Logic (FOL) to formally verify safety and functional correctness properties of the code.  These ATP systems try to build proofs based on user provided domain-specific axioms, which can be arbitrary First-Order-Formulas (FOFs).  That is, these axioms are the crucial trusted base in AutoCert.  However, formulating axioms correctly (i.e.  precisely as the user had really intended) is non-trivial in practice, and speculating validity of the axioms from the ATP systems is very hard since theorem provers do not give examples or counter-examples in general.We adopt the idea of model-based testing to aid axiom authors to discover errors in axiomatization.  To test the validity of axioms, users can define a computational model of the axiomatized logic by giving interpretations to each of the function symbols and constants as computable functions and data constants in a simple declarative programming language.  Then, users can test axioms against the computational model with widely used software testing frameworks.  The advantage of this approach is that the users have a concrete intuitive model with which to test validity of the axioms, and can observe counterexamples when the model does not satisfy the axioms.  We have implemented a proof of concept tool using Template Haskell, QuickCheck, and Yices.(This is a joint work with Ewen Denney at SGT/ NASA Ames Research Center, going to be presented in the poster session at Asian Symposium on Programming Languages and Systems this December.)Bio: Ki Yung Ahn is a Ph.D student at Portland State University working with Tim Sheard and other members of the TRELLYS project, designing and implementing a dependently typed programming language that is general purpose programming friendly. He received a BS in Computer Science from KAIST in 2002, worked as online storage service server programmer at Gretech before joining graduate program at Portland State University in 2005.  He has been working on Shared Subtypes, Korean translation of “Programming in Haskell” by Graham Hutton, and enjoying other small funs of Haskell hacking.

Galois has been holding weekly technical seminars for several years on topics from functional programming, formal methods, compiler and language design, to cryptography, and operating system construction, with talks by many figures from the programming language and formal methods communities. The talks are open and free. An RSVP is not required, but feel free to contact the organizer with questions and comments.