Rigorously assessing software reliability and safety

This paper summarises the state of the art in the assessment of software reliability and safety ("dependability"), and describes some promising developments. A sound demonstration of very high dependability is still impossible before operation of the software; but research is finding ways to make rigorous assessment increasingly feasible. While refined mathematical techniques cannot take the place of factual knowledge, they can allow the decision-maker to draw more accurate conclusions from the knowledge that is available

The Visvalingam algorithm: metrics, measures and heuristics

This paper provides the background necessary for a clear understanding of forthcoming papers relating to the Visvalingam algorithm for line generalisation, for example on the testing and usage of its implementations. It distinguishes the algorithm from implementation-specific issues to explain why it is possible to get inconsistent but equally valid output from different implementations. By tracing relevant developments within the now-disbanded Cartographic Information Systems Research Group (CISRG) of the University of Hull, it explains why a) a partial metric-driven implementation was, and still is, sufficient for many projects but not for others; b) why the Effective Area (EA) is a measure derived from a metric; c) why this measure (EA) may serve as a heuristic indicator for in-line feature segmentation and model-based generalisation; and, d) how metrics may be combined to change the order of point elimination. The issues discussed in this paper also apply to the use of other metrics. It is hoped that the background and guidance provided in this paper will enable others to participate in further research based on the algorithm

Reuse of safety certification artefacts across standards and domains: A systematic approach

Reuse of systems and subsystem is a common practice in safety-critical systems engineering. Reuse can improve system development and assurance, and there are recommendations on reuse for some domains. Cross-domain reuse, in which a previously certified product typically needs to be assessed against different safety standards, has however received little attention. No guidance exists for this reuse scenario despite its relevance in industry, thus practitioners need new means to tackle it. This paper aims to fill this gap by presenting a systematic approach for reuse of safety certification artefacts across standards and domains. The approach is based on the analysis of the similarities and on the specification of maps between standards. These maps are used to determine the safety certification artefacts that can be reused from one domain to another and reuse consequences. The approach has been validated with practitioners in a case study on the reuse of an execution platform from railway to avionics. The results show that the approach can be effectively applied and that it can reduce the cost of safety certification across standards and domains. Therefore, the approach is a promising way of making cross-domain reuse more cost-effective in industry.European Commission's FP7 programm

The Assessment of Quality Maturity Levels in Nigerian University Libraries

Purpose – Organizations constantly evaluate their activities to ensure that they are attaining their management goals. Maturity assessment enables organisations to examine their capabilities, support innovation and evaluate development. This paper evaluates the maturity statuses of a selection of Nigerian university libraries in a study to investigate their quality management (QM) approaches. The study provides recommendations for means to attain the required statuses in academic library development. Design/methodology/approach – The study involved a multisite case study in which interviews were conducted with 15 university librarians (or their representatives) and 10 focus groups were conducted with non-management library staff. The resulting qualitative data was analyzed using an aspect of framework analysis – charting, while a maturity model from the field of project management (Prince 2 Maturity Model, P2MM) was used to assess maturity in QM of the libraries. Findings – The results of the maturity assessment indicate a basic knowledge of the concept of QM implementation amongst the libraries. The scores obtained on the P2MM capability scale placed the libraries studied mainly on Level 1(awareness level) of the model. Practical implications – This paper demonstrates that the culture of QM in academic libraries in Nigeria is at a low level with considerable potential for development. It is suggested that future adoption of quality maturity models to assess performance and organisational effectiveness would aid improvements for value-added services. Originality/value – This is the first study to attempt the assessment of quality maturity levels in Nigerian academic libraries for identification of the organization’s positioning in QM and strategy

A framework for the definition of metrics for actor-dependency models

Actor-dependency models are a formalism aimed at providing intentional descriptions of processes as a network of dependency relationships among actors. This kind of models is currently widely used in the early phase of requirements engineering as well as in other contexts such as organizational analysis and business process reengineering. In this paper, we are interested in the definition of a framework for the formulation of metrics over these models. These metrics are used to analyse the models with respect to some properties that are interesting for the system being modelled, such as security, efficiency or accuracy. The metrics are defined in terms of the actors and dependencies of the model. We distinguish three different kinds of metrics that are formally defined, and then we apply the framework at two different layers of a meeting scheduler system.Postprint (published version