Program Correctness

One of the most important current software issues is re- liability, and accordingly, a major criterion of program- ming language design must be that the language contribute to the production of reliable programs. Although there are other important aspects of software reliability (eg, ...

One of the most important current software issues is re- liability, and accordingly, a major criterion of program- ming language design must be that the language contribute to the production of reliable programs. Although there are other important aspects of software reliability (eg, ...

Model synchronization is one of the key activities of model-driven software development approach. However currently used synchronization methods are quite inefficient since they deal with models’ structure only without analyzing their actual meaning. A great variety of models used in a development process causes certain difficulties when designing a unified model synchronization approach. Moreover, there is no unified methodology, which would help to design model synchronization tools, so the developers have to handle the problem of models’ inconsistency themselves. This paper presents new principles of solving the model synchronization problem based on the definition of synchronization mechanisms in terms of process calculus and the description of their correctness properties in terms of temporal modal logic with further verification by applying rules of logical inference. The main correctness properties of model synchronization process and basic features of designing model synchronization tools are discussed.

Nowadays, due to increasing system complexity and growing competition and costs, industry makes high demands on powerful techniques used to design and analyze manufacturing systems. One of the most popular techniques to do performance analysis is simulation. However, simulation-based analysis cannot guarantee the correctness of a system, so it is less suitable for functional analysis. Our research focuses on examining

In most computer science curricula, formal reasoning about program correctness is taught separately from practical programming, and is thus by most students considered a purely theoretical activity. It has b een a challenge to con- vince students of the practical applicability of formal met hods. We present here an effort to apply Invariant Based Programming(IBP), a visual and practical program

Research in dependent type theories [M-L71a] has, in the past, concentrated on its usein the presentation of theorems and theorem-proving. This thesis is concerned mainlywith the exploitation of the computational aspects of type theory for programming, ina context where the properties of programs may readily be specified and established.In particular, it develops technology for programming with dependent inductive familiesof datatypes

Tabular representations have been proposed for structuring complex mathematical expressions as they appear in the specification of programs. We argue that tables not only help in writing and checking complex expressions, but also in their formal manipulation. More specifically, we explore the use of tabular predicates and tabular relations in program verification and refinement.

This article presents a new formal approach to testing. In the field of dynamic testing, as soon as a program fails for a test set, it is flagged incorrect. The remaining question is: how far can a successful program be considered as correct? We give a definition of program correctness with respect to a specification which is adequate to dynamic testing. Similarly to the field of abstract implementation, the idea is that in order to declare a program as correct, it suffices that its behavior fulfills the specification requirements. An intermediate semantic level between the program and the specification, called the oracle framework, is introduced in order to interpret observable results obtained from dynamic experiments on the program. This allows to give algebraic semantics (i.e. a set of models) to the program, compatible with the program behavior. Program correctness is then defined by some adequacy criterion between the specification semantics and the program semantics. We point out that while for some specifications, there exist exhaustive test sets (the success of which means program correctness), for some other specifications, there only exist “complete” (but not exhaustive) test sets. Of course, all the programs rejected by a complete test set are incorrect but unfortunately, there still exist successful incorrect programs. We also explain how the test set selection can be formalized within our approach.

Chip multiprocessors (CMPs) issue write invalidations (WIs) to assure program correctness. In conventional snoop-based protocols, writers broadcast invalidations to all nodes as soon as possible. In this work we show that this approach, while protecting correctness, is inefficient due to two reasons. First, many of the invalidated blocks are not accessed after invalidation making the invalidation unnecessary. Second, among the invalidated blocks many are not accessed anytime soon, making immediate invalidation unnecessary. While invalidating the first group could be avoided altogether, the second group’s invalidation could be delayed without any performance or correctness cost. Accordingly, we show that there exists an ample opportunity to eliminate and/or delay many WIs without harming performance or correctness. Moreover we investigate invalidation necessity and urgency and show that a large share of WIs could be delayed without impacting program outcome. Our study shows that WIs often repeats their behavior from both the necessity and urgency point of view. Finally we study how eliminating unnecessary WIs could potentially reduce bus occupancy.