Counterexample-guided abstraction refinement (CEGAR) was successfully applied to verify sequential programs. We give a CEGAR scheme for verifying concurrent programs with threads.

As the Director of a Child Advocacy Center that evaluated over 1500 children in 2002 for allegations of child abuse or neglect, I have seen many cases enter the Child Protection system. Of these, only a small percentage was ever accepted for criminal prosecution. Those deemed acceptable differ in two major respects from the vast majority of other cases in which allegations of abuse or neglect a...

Abstract. The exceptions form a computational effect, in the sense that there is an apparent mismatch between the syntax of exceptions and their intended semantics. We solve this apparent contradiction by defining a logic for exceptions with a proof system which is close to their syntax and where their intended semantics can be seen as a model. This requires a robust framework for logics and th...

In this paper we propose an exception logic – formalizing reasoning about exceptions. We use this logic to defend two claims. First, we argue that default logic – formalizing reasoning about default assumptions – is an extension of exception logic. A deconstruction argument shows that reasoning about exceptions is one of the first principles of reasoning about default assumptions. Second, we ar...

Exceptions historically derive from a single-threaded, imperative model of computation. Rather than including tests for the success of subsidiary operations at every procedure level using if-then-else's, it was deemed simpler to describe problems only where they arise and where they are dealt with. The catch-throw style was transferred to C++ (and then Java), and also grafted onto the I/O struc...

Abdel Omran’s 1971 theory of epidemiological transition is an attempt to account for the extraordinary advances in health care made in industrialized countries since the 18 century. According to Omran, all societies experience three "ages" in the process of modernization: the "age of pestilence and famine", during which mortality is high and fluctuating, with an average life expectancy under 30...

This paper shows that default-based phonologies have the potential to capture morphophonological generalisations which cannot be captured by non-default theories. In achieving this result, I offer a characterisation of Underspecification Theory and Optimality Theory in terms of their methods for ordering defaults. The result means that machine learning techniques for bull(ling declm'ative analy...

In a recent paper, Peyton Jones et al. proposed a design for imprecise exceptions in the lazy functional programming language Haskell PJRH + 99]. The main contribution of the design was that it allowed the language to continue to enjoy its current rich algebra of transformations. However, it does not combine easily with other extensions, most notably that of concurrency. We present an alternati...

This paper provides a principled answer to the question of how todeal with conflicting default rules. It does so in two ways: semanticallywithin a circumscriptive theory, and syntactically by supplying analgorithm for inheritance networks. Arguments that can be expressedin both frameworks are valid on the circumscriptive account if andonly if the inheritance algorithm ha...

Algorithmic Skeletons offer high-level abstractions for parallel programming based on recurrent parallelism patterns. Patterns can be combined and nested into more complex parallelism behaviors. Programmers fill the skeleton patterns with the functional (business) code, which transforms the generic skeleton into a specific application. However, when the functional code generate exceptions, this...