USTOPIA REQUIREMENTS THOUGHTS ON A USER-FRIENDLY SYSTEM FOR TRANSFORMATION OF PROGRAMS IN ABSTRACTO

Transformational programming is a program development method which is usually applied using 'pen and paper'. Since this requires a lot of clerical work (copying expressions, con- sistent substitution) which is tiresome and prone to error, some form of machine support is desirable. In this paper a number of systems are described that have already been built to this aim. Some of their shortcomings and limitations are identified. Based on experience with program transformation and transformation systems, a long list of features is given that would be useful in an 'utopian' transformation system. This list is presented using an orthogonal division of the problem area. A number of problems with the realisation of some aspects of our 'utopian' system are identified, and some areas for further research are indicated

Floating constraints in lexical choice

Lexical choice is a computationally complex task, requiring a generation system to consider a potentially large number of mappings between concepts and words. Constraints that aid in determining which word is best come from a wide variety of sources, including syntax, semantics, pragmatics, the lexicon, and the underlying domain. Furthermore, in some situations, different constraints come into play early on, while in others, they apply much later. This makes it difficult to determine a systematic ordering in which to apply constraints. In this paper, we present a general approach to lexical choice that can handle multiple, interacting constraints. We focus on the problem of floating constraints, semantic or pragmatic constraints that float, appearing at a variety of different syntactic ranks, often merged with other semantic constraints. This means that multiple content units can be realized by a single surface element, and conversely, that a single content unit can be realized by a variety of surface elements. Our approach uses the Functional Unification Formalism (FUF) to represent a generation lexicon, allowing for declarative and compositional representation of individual constraints

Coherence check of behavioural specifications against specific properties of the operational context

In der Anforderungsspezifikation eines Systems werden Eigenschaften definiert, die das System an seiner Schnittstelle zur Umgebung aufweisen muss, um im Betrieb seinen Zweck zu erfüllen. Eine Vielzahl von Untersuchungen zeigt, dass Fehler in der Anforderungsspezifikation zu erheblichen negativen Konsequenzen sowohl im Entwicklungsprozess des Systems als auch im Systembetrieb führen können. Fehler in der Anforderungsspezifikation sind dabei oftmals auf Kohärenzbrüche gegenüber dem operationellen Kontext zurückzuführen, d. h. auf ungültige oder unvollständige Annahmen über die Umgebung, in der das System betrieben werden soll. Im Rahmen des Dissertationsvorhabens wurde ein teilautomatisierter Ansatz entwickelt, der darauf abzielt, Kohärenzbrüche in der Anforderungsspezifikation von Systemen gegenüber dem operationellen Kontexts dieser Systeme aufzudecken. Die Arbeit fokussiert dabei auf die Verhaltensspezifikation als Teil der Anforderungsspezifikation sowie auf Eigenschaften des operationellen Kontexts in der statisch-strukturellen Perspektive. Der entwickelte Ansatz setzt sich aus einem Rahmenwerk zur Modellierung des operationellen Kontexts in der statisch-strukturellen Perspektive und einem Katalog von Formalismen zusammen, durch deren Anwendung Kohärenzbrüche in der Verhaltensspezifikation teilautomatisiert aufgedeckt werden können. Zur Evaluation des Ansatzes wurde dieser exemplarisch auf die Verhaltensspezifikation eines von Komplexität und Umfang her praxistypischen Systems angewendet. Zum Nachweis der technischen Umsetzbarkeit des Ansatzes wird ein Werkzeugprototyp vorgestellt. Der entwickelte Ansatz liefert einen Beitrag im Hinblick auf Techniken zur differenzierten Modellierung des operationellen Kontexts von Systemen in der statisch-strukturellen Perspektive und zur teilautomatisierten analytischen Qualitätssicherung von Anforderungsspezifikationen.The requirements specification of a system contains the definition of properties the system must exhibit at its interfaces with the environment in order to meet its purpose during system operation. There is ample evidence in the literature that suggests that errors in the requirements specification may lead to serious negative consequences during the development process of the system as well as subsequently, during system operation. Errors in the requirements specification can often be traced back to the fact that the specification is not coherent with the operational context due to invalid or incomplete assumptions about the system’s operating environment. In the context of this dissertation, a semi-automated approach was developed, aiming at detecting coherence defects within a system’s requirements specification against its operational context. The focus of this thesis lies on the specification of the system’s behaviour as part of the requirements specification and on properties of the operational context in the structural perspective. An approach has been developed that consists of a framework for modelling the operational context in the structural perspective. Furthermore, a list of formalisms has been devised, which allow detecting coherence defects in the specification of the system’s behaviour in a partially automated way. For validation purposes, the approach was exemplarily applied to the specification of a system that renders a typical real-world example with regard to complexity and extent. To prove the technical feasibility of the approach, a tool prototype is presented. The dissertation provides a contribution with regard to techniques for modelling the operational context of systems in the structural perspective as well as for the partially automated, analytic quality assurance of requirements specification