The paper describes the MIKE (Model-based and Incremental Knowledge Engineering) approach for the development of knowledge-based systems (kbs). It integrates semiformal specification techniques, formal specification techniques, and prototyping into a coherent framework. This allows the domain and task model of a kbs to be described on different formalization levels. All activities in the building process are embedded in a cyclic life cycle model. For the semiformal representation we use a hypermedia-based formalism which serves as a communication basis between expert and knowledge engineer during knowledge acquisition. The semiformal knowledge representation is also the basis for formalization, resulting in a formal and executable model of expertise specified in the Knowledge Acquisition and Representation Language (KARL). Since KARL is executable the model of expertise can be developed and validated by prototyping. A smooth transition from a semiformal to a formal specification and fu...

Scenarios play an important role throughout the information system development process. Scenarios are partial descriptions of system and environment behavior arising in restricted situations. They are instrumental to the following activities: describing and clarifying the relevant properties of the application domain, uncovering system requirements, evaluating design alternatives, and validating designs. This paper will describe these roles in the context of an example and explain how computer-based tools can support the use of scenarios throughout the development process. The thesis of this paper is based on experience with three such computer-based tools. Keycodes: D.2.1; D.2.6 Keywords: Requirements/Specification; Programming Environments 1 Introduction This paper argues that scenarios have an important role to play in the information system development process. Scenarios are partial descriptions of system and environment behavior arising in restricted situations. Both the behavior...

This paper presents such a tool, the MODELEXPLAINER, Or MoDEx for short

: This paper offers a framework and a process model for comparing requirements from different stakeholders. The framework combines a knowledge based system approach to requirements elicitation, a mathematically based technique for conceptual modelling, a four-state model of comparison to identify different types of conflict, a number of strategies to resolve inconsistencies and a distance metric for determining if viewpoints are converging. The framework is an extension of a knowledge engineering framework for reconciling differences between multiple sources of expertise. To justify this extension a comparison is made between the nature of knowledge and requirements and the issues that face both disciplines. The paper focuses on the common issues of maintenance and combining requirements, which are regarded as a specialised type of knowledge. Keywords: requirements engineering, knowledge engineering, ripple down rules, formal concept analysis 1 Using Knowledge Engineering Techniques ...

. This paper describes a method for estimating the salience of features comprising conceptual descriptions of software artifacts. Salience estimates are used in a model analyzing the similarity between such descriptions so as to promote the analogical reuse of the artifacts described by them. Salience is conceived as belief on the dominance of a feature, which is defined on the basis of three general properties that a feature may have in a conceptual model, namely the abstractness, the characteristicity and the causality. This belief is measured according to evidence inherent in conceptual schemas organizing software repositories. 1. Introduction In this paper, we define a method for evaluating the salience of features comprising conceptual descriptions of software artifacts(i.e code, designs or specifications). The method has been implemented by a system estimating similarities between such descriptions of software artifacts so as to promote their analogical reuse[18]. The analysis o...

. Evolution is a fact of life in information systems. Not only systems evolve but also their development processes. IS environments must therefore be designed for accommodating and managing change. The management of process meta models in repositories is one important step; we show how process traceability models and process guidance models can be developed and related in a standard repository framework. In addition, the currently available tool integration along the presentation, data, and control perspectives have to be augmented for process integration. In our process-adaptable and interoperable tool concept, tool behavior is directly influenced by the process guidance model and automatically traced according to the traceability model. The approach is demonstrated with a prototype requirements engineering environment developed in ESPRIT project NATURE. 1 Information Systems and the Process Improvement Paradigm Information systems (IS) are networks of humans and information technolo...

The success and acceptance of reuse tools and libraries depends on their integration into existing software development environments. However, the addition of large libraries of reusable components to software design databases only exacerbates the problem of design data management. Object-oriented databases originated to meet the requirements of design data management that relational databases could not satisfy. This paper describes a semantic data model for an object-oriented database supporting an integrated Computer Aided Software Engineering environment (CASE). The data model promotes reuse by providing objects that match program design requirements to existing components in the reuse library. 1 Keywords: Software reuse, Computer-Aided Software Engineering, CASE, Semantic data modelling, Object-Oriented Database Systems. 1.0 Overview To successfully insert reuse into the software development process, we must integrate support for reuse into existing software tools and CASE environ...

Formal descriptions, while difficult for most human readers to understand, are convenient for specifying large software systems, where completeness and consistency are important issues. Informal specifications can offer advantages in readability, but ambiguities and contradictions are unavoidable side-effects. Since a specification often acts as a formal contract between the software developer and the customer, it is essential that both sides be able to fully understand the specification document. Systems have been proposed which help the software client better understand the specification by automatically paraphrasing it in natural language. Metaview is a customizable metasystem that facilitates the construction of software specification environments that can be used to support software specification tasks. This paper describes a strategy for producing natural language descriptions of formal software requirements specifications developed using Metaview specification environments. A c...

This paper describes the DD framework for domain modelling in information systems engineering. Such...

In current practice, formal methods are perceived as high-cost activities, and hence their use is recommended primarily for cases warranting the highest possible level of assurance. However, opportunities abound for beneficial applications of formal methods across a broad spectrum of cases, provided low-cost pathways towards their introduction and use can be identified. This premise is illustrated on a fragment of space vehicle requirements. Other researchers have studied fragments similar to this to illustrate various analysis techniques. Here it is shown that judicious choice of representation permits (some) formal analysis to be conducted immediately. Furthermore, this representation is made alluring by automatically generating textual and tabular representations from it. The net result is a low-cost (perhaps even costsavings) approach to manipulating requirements of this nature, with the beneficial side effect of permitting formal analysis of those requirements at no extra cost. 1.1 Keywords Analysis, flowcharts, formal methods, requirements, tabular