摘要:

This paper provides a preliminary overview of a procedure for monitoring software development with respect to quality. The monitoring process is based on the extraction, analysis and interpretation of metrics relating to software products and processes. In particular, we are concerned with the problem of interpreting software metrics data in terms that are meaningful to project and quality managers. We present a four-stage model of the interpretation of metrics which comprises the identification of abnormal metric values (i.e. exceptions), possible causes of exceptions, additional information required to distinguish between causes, and possible corrective actions. We envisage that the model could be implemented as an advice system for managers. We discuss the general principles of project monitoring throughout the development life-cycle, and identify metrics that may be collected throughout, from requirements specification to integration testing. We suggest some general principles for assessing the cause of abnormal metric values, for distinguishing between causes, and for responding to unfavourable project circumstances.

DOI:10.1049/sej.1989.0001

出版商:IEE    

年代:1989

数据来源: IET

摘要:

A non-interactive, binary relational database programming language is designed using formal specification. The design is conducted using the Vienna development method. The underlying data model is made as general as possible so as to minimise the restrictions placed on the database user. In contrast to the normal method of handling database integrity constraints by dynamic checking, constraints are regarded as assertions, and proofs of correctness based on Hoare-style axioms and proof rules are used to show that semantic integrity is maintained.

DOI:10.1049/sej.1989.0002

出版商:IEE    

年代:1989

数据来源: IET

DOI:10.1049/sej.1989.0003

出版商:IEE    

年代:1989

数据来源: IET

摘要:

Recent developments in mathematics and computer science offer a sound, if unfamiliar, basis for the development of computer-controlled systems. The professional systems engineer should become as competent in these fields as he is (expected to be) in traditional mathematics and physics. The paper emphasises their application in the early phases of product development (requirements analysis and functional specification) – a prerequisite for their successful use in design and implementation. Some important aspects of ‘embedded’ computer systems, such as concurrency, have not been discussed because space does not allow an adequate introduction to their formal treatment.

DOI:10.1049/sej.1989.0004

出版商:IEE    

年代:1989

数据来源: IET

摘要:

The differences in the above title to the original title of ‘A justification of formal methods’ reflect the three main themes of this paper: • the developments which have occurred in the theory, support and exploitation of the mathematical techniques for software (and systems) design, which are collectively known as formal methods, since the publication of the paper with the original title (in Software and Microsystems, August 1982) • the growing dissatisfaction of both the academic and industrial communities with the use of the term ‘method’ in this context • the continuing need to justify to the industrial community that the use of mathematically sound design techniques, by an appropriately educated workforce, is a necessary, albeit not sufficient, factor in their quest for increased quality, productivity, responsiveness and manageability in the software development process.

DOI:10.1049/sej.1989.0005

出版商:IEE    

年代:1989

数据来源: IET

摘要:

This paper provides an introduction to the description of information systems using formal, mathematical specifications written in the Z notation, and to the refinement of these specifications into rigorously checked designs. The first part introduces the idea of a formal specification using a simple example: that of a ‘birthday book’ in which people's birthdays can be recorded, and which is able to issue reminders on the appropriate day. The behaviour of this system for correct input is specified first; then the schema calculus is used to strengthen the specification into one requiring error reports for incorrect input. The second part of the paper introduces the idea of data refinement as the primary means of constructing designs which achieve a formal specification. Refinement is presented through the medium of two examples: the first is a direct implementation of the birthday book from part one; and the second is a simple checkpoint facility, which allows the current state of a database to be saved and later restored. A Pascal-like programming language is used to show the code for some of the operations in the examples.

DOI:10.1049/sej.1989.0006

出版商:IEE    

年代:1989

数据来源: IET

摘要:

In the specification notation known as Z,schemasare used to structure mathematical descriptions. This paper describes the language of schemas and the conventions that are employed in their use. It also describes how proof obligations are generated during specification, and how these obligations may be discharged. The paper contains many examples, mostly taken from the specification of the user interface to a small, but realistic, software component.

DOI:10.1049/sej.1989.0007

出版商:IEE    

年代:1989

数据来源: IET

摘要:

A simple text processing tool which allows positioning of lines within a document is presented using the formal specification language Z. Implementation details such as the use oftabcharacters andnewlinesequences are covered. The program has been implemented under the UNIX operating system. It is hoped that the use of similar techniques will become widespread in the field of software engineering.

DOI:10.1049/sej.1989.0008

出版商:IEE    

年代:1989

数据来源: IET