Automated verification of termination certificates

In order to increase user confidence, many automated theorem provers provide certificates that can be independently verified. In this paper, we report on our progress in developing a standalone tool for checking the correctness of certificates for the termination of term rewrite systems, and formally proving its correctness in the proof assistant Coq. To this end, we use the extraction mechanism of Coq and the library on rewriting theory and termination called CoLoR

Termination and Cost Analysis with COSTA and its User Interfaces

COSTA is a static analyzer for Java bytecode which is able to infer cost and termination information for large classes of programs. The analyzer takes as input a program and a resource of interest, in the form of a cost model, and aims at obtaining an upper bound on the execution cost with respect to the resource and at proving program termination. The costa system has reached a considerable degree of maturity in that (1) it includes state-of-the-art techniques for statically estimating the resource consumption and the termination behavior of programs, plus a number of specialized techniques which are required for achieving accurate results in the context of object-oriented programs, such as handling numeric fields in value analysis; (2) it provides several nontrivial notions of cost (resource consumption) including, in addition to the number of execution steps, the amount of memory allocated in the heap or the number of calls to some user-specified method; (3) it provides several user interfaces: a classical command line, a Web interface which allows experimenting remotely with the system without the need of installing it locally, and a recently developed Eclipse plugin which facilitates the usage of the analyzer, even during the development phase; (4) it can deal with both the Standard and Micro editions of Java. In the tool demonstration, we will show that costa is able to produce meaningful results for non-trivial programs, possibly using Java libraries. Such results can then be used in many applications, including program development, resource usage certification, program optimization, etc

Out of plane analysis for composite structures

Simple two dimensional analysis techniques were developed to aid in the design of strong joints for integrally stiffened/bonded composite structures subjected to out of plane loads. It was found that most out of plane failures were due to induced stresses arising from rapid changes in load path direction or geometry, induced stresses due to changes in geometry caused by buckling, or direct stresses produced by fuel pressure or bearing loads. While the analysis techniques were developed to address a great variety of out of plane loading conditions, they were primarily derived to address the conditions described above. The methods were developed and verified using existing element test data. The methods were demonstrated using the data from a test failure of a high strain wingbox that was designed, built, and tested under a previous program. Subsequently, a set of design guidelines were assembled to assist in the design of safe, strong integral composite structures using the analysis techniques developed