A feature is a part or aspect of a speciication which a user perceives as having a self-contained functional role. In large speciications there are several problems that make the manipulation of features diicult: the part of the speciication describing a feature is widely distributed over the whole speciication, and features may interact in ways that are hard to predict. To overcome these probl...

When students first learn programming, they often rely on a simple operational model of a program’s behavior to explain how particular features work. Because such models build on their earlier training in algebra, students find them intuitive, even obvious. Students learning type systems, however, have to confront an entirely different notation with a different semantics that many find difficul...

The life cycle cost of a system is influenced by its maintainability. Maintainability is a design parameter, whose operational conditions can affect it significantly. Hence, the effects of these operational conditions should be quantified early in the design phase. The proportional repair model (PRM), which is developed based on the proportional hazard model (PHM), can be used to analyze mainta...

In this paper we present a preliminary analysis of the suitability of using PVS as a tool for developing operational semantics and programming logics in a semi-automatic fashion. To this end we present a formalized proof of the Church–Rosser theorem for a version of the call-by-value lambda calculus in the spirit of Landin’s ISWIM. The proof is developed in the PVS system, and is used as a test...