Browse Theses

Many software errors are due to the correct implementation of incorrectly specified requirements. For example, software designers may fail to make their assumptions explicit or may state inconsistent or ambiguous requirements. The best review process is inspection by customers and software developers who are experienced in the application area. Despite such efforts, errors persist in requirements.

This dissertation describes methods and tools for automatically analyzing software requirements before system design begins. Systems are described as state machines with event-driven transitions using a specification language that is intuitive, easy to read, and scalable to large systems. We have developed a methodology for formalizing state-transition requirements and an algorithm for transforming the formalized requirements into a representation that can be analyzed with a model checker. The result is a formal specification and analysis technique for verifying behavioral and timing requirements of real-time systems.

Using a tool implementing our algorithm and an existing model checking tool, we were able to uncover violations of system invariants in existing requirements specifications that had either been inspected or had been implemented and tested. We were also able to verify the safety and timing properties of existing discrete real-time specifications.