150 research outputs found
A Formally Grounded Software Specification Method
No full textOne of the goals of software engineering is to provide what is necessary to write relevant, legible, useful descriptions of the systems to be developed, which will be the basis of successful developments. This goal was addressed both from informal approaches (providing in particular visual notations) and formal ones (providing
a formal sound semantic basis). Informal approaches are often driven by a software development method, and, while formal approaches sometimes provide a user
method, it is usually aimed at helping to use the proposed formalism when writing a specification. Our goal here is to provide a companion method that helps the user
to understand the system to be developed, and to write the corresponding formal specifications. We also aim at supporting visual presentations of formal specifications, so as to “make the best of both formal and informal worlds”.
We developed this method for the (logical-algebraic) specification languages Casl (Common Algebraic Specification Language, developed within the joint initiative CoFI) and for an extension for dynamic systems Casl-Ltl, and we believe it is general enough to
be adapted to other paradigms.
Another challenge is that a method that is too general does not encompass the different kinds of systems to be studied, while too many different specialized methods result in partial views that may be difficult to integrate in a single global one. We deal with this issue by providing a limited number of instances of our method, fitted for three different kinds of software items, while keeping a common “meta”- structure and way of thinking. More precisely, we consider here that a software item
may be a simple dynamic system, a structured dynamic system, or a data structure, and we show here how to support property-oriented (axiomatic) specifications. We
are thus providing support for the “building-bricks” tasks of specifying software artifacts that in our experience are needed for the development process.
Our approach is illustrated with a lift case study
choppy
No full textchoppy[PT] Explanation. When white waves are on the water the sea is said to be "choppy."Yes#173 J. D. A. WIDDOWSON COLLECTOR'S PERMANENT FILENot usedNot usedWithdrawnChecked by Jordyn Hughes on Mon 18 Jul 201
A UML-Based Approach for Problem Frame Oriented Software Development
No full textWe propose a software development approach that combines the use of the structuring concepts provided by problem frames, the use of the UML notation, together with our methodological approach for well-founded methods. Problem frames are used to provide a first idea of the main elements of the problem under study. Then we provide ad hoc UML based development methods for some of the most relevant problem frames together with precise guidelines for the users. The general idea of our method is that, for each frame, several artifacts have to be produced, each one corresponding to a part of the frame. The description level may range from informal and sketchy, to formal and precise, while this approach is drawn from experience in formal specifications.
Thus we show how problem frames may be used upstream of a development method to yield an improved and more efficient method equipped with the problem frames structuring concepts
Using CASL to Specify the Requirements and the Design: A Problem Specific Approach
No full textIn [11] M. Jackson introduces the concept of problem frame to describe specific classes of problems, to help in the specification and design of systems, and also to provide a framework for reusability. He thus identifies some particular frames, such as the translation frame (e.g., a compiler), the information system frame, the control frame (or reactive system frame), . . . . Each frame is described along three viewpoints that are application domains, requirements, and design.
Our aim is to use Casl (or possibly a sublanguage or an extension of Casl if and when appropriate) to formally specify the requirements and the design of particular classes of problems (“problem frames”). This goal is related to methodology issues for Casl, that are here addressed in a more specific way, having in mind some particular problem frame, i.e., a class of systems.
It is hoped that this will provide both a help in using, in a really effective way, Casl for system specifications, a link with approaches that are currently used in the industry, and a framework for the reusability. This approach is illustrated with some case studies, e.g., the information system frame is illustrated with the invoice system
Casl-Mdl, Modelling Dynamic Systems with a Formal Foundation and a UML-Like Notation
No full textIn this paper we present a part of Casl-Mdl, a visual modelling notation based on Casl-Ltl (an extension for dynamic system of the algebraic specification language Casl). The visual constructs of Casl-Mdl have been borrowed from the UML, thus existing editors may be used. A Casl-Mdl model is a set of diagrams but it corresponds to a Casl-Ltl specification, thus Casl-Mdl is a suitable means to easily read and write large and complex Casl-Ltl specifications. We use as a running example a case study that describes the functioning of a consortium of associations
Choppy Waters
No full textThe movement toward a uniform standard for confidentiality in mediation among the states is one that from the outset casts off into choppy waters, marked by pitching cross-currents of remarkable force
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