COMPEURO'90: Proceedings of the 1990 IEEE International Conference on Computer Systems and Software Engineering@m_Systems Engineering Aspects of Complex Computerized Systems
JSD (Jackson System Development method) is a system development method. Although the underlying p... more JSD (Jackson System Development method) is a system development method. Although the underlying philosophy of JSD promotes orthogonality of system components in it specification, it fails to make explicit the business requirement policies that define the systems. The formalism adopted by JSD implicitly translate user requirement policies into lower-level procedural representation, thus burying the requirement policies in program code. The difficulty with such form of translation becomes apparent when user requirements change. Accommodating requirement changes then would be expensive. This paper recognises the advantage of using rules in representing user requirement policies and suggests the use of rules in making explicit the representation of business requirement policies in a JSD specification, so a s t o enhance the maintainability of a system.
The Data-Gathering Broker--A User-Based Approach to Viable EPR Systems
Studies in Health Technology and Informatics, 2005
With the continued expansion of Electronic Patient Record systems ahead of comprehensive evidence... more With the continued expansion of Electronic Patient Record systems ahead of comprehensive evidence, metrics, or future-proofing, European health informatics is embarking on a faith-driven adventure that also risks data swamping of end-users. An alternative approach is an information broker system, drawing from departmental data sources. A three-year study in health and social care has produced a first demonstrator which can search for specified information in heterogeneous distributed data stores, with source-specific permission can copy it, and then merge the search results in a real-time process.
Managing healthcare information: the role of the broker
Studies in Health Technology and Informatics, 2005
We describe a prototype information broker that has been developed to address typical healthcare ... more We describe a prototype information broker that has been developed to address typical healthcare information needs, using web services to obtain data from autonomous, heterogeneous sources. Some key features are reviewed: how data sources are turned into data services; how we enforce a distributed access control policy; and how semantic interoperability is achieved between the broker and its data services. Finally, we discuss the role that such a broker might have in a Grid context, as well as the limitations this reveals in current Grid provision.
this report is an attempt to encourage and stimulate wider discussion about the long-term softwar... more this report is an attempt to encourage and stimulate wider discussion about the long-term software research agenda. The goals of the work reported here are therefore: . to form a vision of the future of software and software development, based upon systematic use of expert judgement and peer review . to establish the need for a long-term research agenda . to propose a long-term research agenda that can help meet the future needs of society for software that is reasonably-priced, reliable, adaptable and available when needed In recent years, a number of publications have addressed hopes for, and predictions of, the future of software and software development. Indeed, predicting the 14/08/00 3 future has been a popular pastime in many disciplines over many years. In the field of software, a recent special issue of CACM contained many personal hopes and visions for the future of technology [1]. Contributors express individual, focused views relating to particular technologies and appli...
developed, and delivered as a product. However, the Internet has created a recent surge of intere... more developed, and delivered as a product. However, the Internet has created a recent surge of interest in developing software as a service delivered and consumed on demand. The benefit of this approach is seen in the looser coupling between business problems and the associated software solutions—hence the increased ability to evolve systems as business requirements change. This shift toward a service-oriented model of software brings about a number of benefits as well as research challenges. The concept of delivering software as a service is relatively simple: “Do not buy software, simply use it as and when you need it.” Putting such a concept into practice, however, is far more complex and involves many issues. In this article, we address the questions: What are the characteristics of a market for software services? What are the characteristics of negotiating in such an environment? The work presented here is based upon ongoing research into service-oriented software and is designed t...
Maintenance of Object-Oriented C++ Software : A Protocol Study
A protocol study has been conducted which examines the strategies intermediate level programmers ... more A protocol study has been conducted which examines the strategies intermediate level programmers use along and the errors which are made when a small number of experimental problems written using the language C++ are maintained. An integrated compilation and editing environment has been developed which captures editing events, such as cursor movements, keystrokes and compilation attempts. Maintenance strategy and error analysis utilises both data captured from the compilation environment and verbal protocols. Some suggestions for further research is given.
Software evolution can result in making a program harder to maintain, as it becomes more difficul... more Software evolution can result in making a program harder to maintain, as it becomes more difficult to comprehend. This difficulty is related to the way the source code is formatted, the complexity of the code, and the amount of information contained within it. This paper presents an initial approach that uses measures of typographical style, spatial complexity and concept assignment to measure these factors, and to model the comprehensibility of an evolving program. The ultimate aim of which is to identify when a program becomes more difficult to comprehend, triggering a corrective action to be taken to prevent this. We present initial findings from applying this approach. These findings show that this approach, through measuring these three factors, can model the change in comprehensibility of an evolving program. Our findings support the well-known claim that programs become more complex as they evolve, explaining this increase in complexity in terms of layout changes, conceptual coherence, spatial relationships between source code elements, and the relationship between these factors. This in turn can then be used to understand how maintenance affects program comprehensibility and to ultimately reduce its burden on software maintenance.
The paper investigates the applicability of data mining in software reliability assessment and ma... more The paper investigates the applicability of data mining in software reliability assessment and maintenance. The proposed methodology comprises three steps. First the input models are defined by selecting parts of the source code, such as functions, routines and variables, to populate a database. Then Clustering is applied to identify subsets of source code that are grouped together according to custom-made similarity metrics. Finally Association rules are used to establish inter-group and intra-group relationships. Experimental results show that the methodology can assess modularity, detect complexity and predict the impact of changes.
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Papers by Paul Layzell