Mehmet Bülent Özcan

Towards quality requirements via animated formal specifications

Assuring a high quality requirements specification document involves both an early validation process and an increased level of participation. An approach and its supporting environment which combines the benefits of a formal system specification and its subsequent execution via a rapid prototype is reported. The environment assists in the construction, clarification, validation and visualisation of a formal specification. An illustrative case study demonstrates the consequences of assertions about system properties at this early stage of software development. Our approach involves the pragmatic combination of technical benefits of formal systems engineering based techniques with the context‐sensitive notions of increased participation of both developer and user stakeholders to move us closer towards a quality requirements specification document.

Validating and evolving software requirements in a systematic framework

The concern is with validation and evolution of software requirements based on the notion of executable specifications. A fundamental premise of this approach is that it is possible to use executable specification descriptions and conventional implementation descriptions interchangeably. This allows a prototype system to be transformed into a production quality system by incrementally replacing specifications with implementations which conform to them.<<ETX>>

Visualisation of Executable Formal Specifications for User Validation

This paper reports on research work to facilitate the user validation process in an application-orientated fashion based on executable formal specifications. It is part of an ongoing effort to move towards quality requirements via graphical visualisations of formal specifications. It builds upon previous work that supports the animation of Z specifications in a LISP-based environment called ZAL (Z Animation in LISP). In addition, it embodies a visualisation system called ViZ (Visualisation in Z) which enables the comprehension, clarification and validation of executable formal specification notations. Technology provided by ViZ allows software developers to choose an appropriate representation of objects used in an executable formal specification and create dynamic and/or static animations of these objects in an interactive and iterative fashion. ViZ provides a generic visualisation model to capture the process of visualising static and dynamic behaviour of a ZAL specification. This paper outlines our approach, details ViZ and illustrates its application in a real-world setting.

Interchanging specifications and implementations in evolutionary prototyping

The strategy of retrofitting quality onto a prototype and evolving it into a production quality system has at best led to severe problems and at worst to a complete failure. The present work reports on an environment and methodology that supports the development of high quality prototypes that can easily accommodate changes so that the prototypes can be evolved into production quality systems. An outline of the environment incorporating an architectural mechanism and associated tools that accommodates the intertwining of algebraic specifications, known as ADTSPEC, and implementations in a modular programming language, PARADOX PASCAL, is presented. A framework for applying the environment in the context of evolutionary development is detailed. An illustrative application is also presented. It demonstrates the effectiveness of the work, to support user participation at each stage of evolution and the engineering of high quality prototypes constructed in a systematic manner, incorporating the degree of rigour that is appropriate to the clarity of requirements.

Investigating annotation in electronic paper-prototypes

Many design activities depend on communicative activities around collaboratively produced prototypes. A common communication practice in producing text documents is to add annotation in the form of comments. Previous research indicates that electronic paper-prototyping can be used to rapidly create simple prototypes of interactive systems, such as websites. Little is known, however, about how to provide and maintain variety of communication channels around such electronic paper-prototypes to enable end-users and other stakeholders to contribute to design dialogues. This paper presents Gabbeh, an electronic paper-prototyping tool, and reports on an evaluation using the tool in a simulated design exercise.

Requirements validation based on the visualisation of executable formal specifications

This paper reports on ongoing research work to facilitate the user validation process based on executable formal specifications. It embodies a visualisation system which allows software developers to choose an appropriate representation of objects used in a formal specification and create a dynamic and/or static animation of these objects in an interactive and iterative fashion. This paper outlines our approach and illustrates its application in a real-world setting.

Use of executable formal specifications in user validation

Requirements validation through feedback with users is of paramount importance in producing a high quality requirements specification document. Use of an executable formal specification offers an effective combination of formalism and pragmatism. This allows not only the systematic development of a concise specification of a system, but it also enables developers to execute the specification to receive feedback at an early stage. Executable formal specification languages have traditionally been used as an effective prototyping tool to facilitate developer validation, that is the developer can, via specification execution either individually or in a peer review format, explore the consequences of the specification. However, their use in requirements validation is often not user orientated, which may in turn reduce the effectiveness of the approach.