Strategies for Introducing Formal Methods into the ADA Life Cycle

This is the final report of a short study of the applicability of formal definition techniques to program development activities with specific emphasis on using the programming language Ada. The portion of the study here encompasses three elements: - A review of the various formal defition techniques; - A study of the existing and planned tools in programming development environments; - An examination of life cycle methodologies with the objective of inserting formalized techniques

Graph models for reachability analysis of concurrent programs

Reachability analysis is an attractive technique for analysis of concurrent programs because it is simple and relatively straightforward to automate, and can be used in conjunction with model-checking procedures to check for application-specific as well as general properties. Several techniques have been proposed differing mainly on the model used; some of these propose the use of flowgraph based models, some others of Petri nets.This paper addresses the question: What essential difference does it make, if any, what sort of finite-state model we extract from program texts for purposes of reachability analysis? How do they differ in expressive power, decision power, or accuracy? Since each is intended to model synchronization structure while abstracting away other features, one would expect them to be roughly equivalent.We confirm that there is no essential semantic difference between the most well known models proposed in the literature by providing algorithms for translation among these models. This implies that the choice of model rests on other factors, including convenience and efficiency.Since combinatorial explosion is the primary impediment to application of reachability analysis, a particular concern in choosing a model is facilitating divide-and-conquer analysis of large programs. Recently, much interest in finite-state verification systems has centered on algebraic theories of concurrency. Yeh and Young have exploited algebraic structure to decompose reachability analysis based on a flowgraph model. The semantic equivalence of graph and Petri net based models suggests that one ought to be able to apply a similar strategy for decomposing Petri nets. We show this is indeed possible through application of category theory

State TANF Policy and Services to People With Disabilities

The intent of this study is to identify state policies and procedures that are designed to ensurethat people with disabilities and/or parents with children with disabilities are provided theopportunity to participate in state TANF programs. The intent is not to present "best practices," with quantifiable and measurable outcomes. Many state TANF programs are still in their early stages, with new programs being developed and outcomes still uncertain. The intent is to present an in-depth "snapshot" of what is occurring right now at the state level in terms of services and programs designed to assist TANF recipients with disabilities. Are states developing programs and policies specifically targeted toward people with disabilities? Are people with disabilities being served on an individual basis as part of the overall TANF population? Are states developing innovative strategies that particularly benefit TANF recipients with disabilities and, if so, what are they? By identifying these strategies, this report may assist other states in their policy development process in support of people with disabilities and parents with children of disabilities

A Historical Perspective on Runtime Assertion Checking in Software Development

This report presents initial results in the area of software testing and analysis produced as part of the Software Engineering Impact Project. The report describes the historical development of runtime assertion checking, including a description of the origins of and significant features associated with assertion checking mechanisms, and initial findings about current industrial use. A future report will provide a more comprehensive assessment of development practice, for which we invite readers of this report to contribute information