Specification Phase Research Articles

LAN/WAN interworking

This paper presents an overview of some of the elements which make up current discussions on LAN/WAN interworking, with particular emphasis on OSI LAN and WAN environments. It does not seek to give a detailed technical analysis in these areas, since such an analysis is the subject of work being undertaken by RARE as part of the COSINE specification phase. The aim is to give a background description to the detailed technical work and to the ongoing discussions within the RARE community. It concludes with observations based on experience of existing open systems LAN/WAN interworking scenarios and services within the UK academic community.

Program complexity using Hierarchical Abstract Computers

A model of program complexity is introduced which combines structural control flow measures with data flow measures. This complexity measure is based upon the prime program decomposition of a program written for a Hierarchical Abstract Computer. It is shown that this measure is consistent with the ideas of information hiding and data abstraction. Because this measure is sensitive to the linear form of a program, it can be used to measure different concrete representations of the same algorithm, as in a structured and an unstructured version of the same program. Application of the measure as a model of system complexity is given for “upstream” processes (e.g. specification and design phases) where there is no source program to measure by other techniques.

Computer modelling of the performance of centrifugal water chillers in mine refrigeration installations

The non-specific behaviour of centrifugal water chillers is investigated. The conclusions reached are mainly based on calculations performed by the computer programs developed for the project. A better understanding of the influence of the chiller operating parameters will enable designers to optimize part-duty operation during the specification phase and enable operators to improve the running of existing installations.

Case study: The PAISLey approach applied to its own software tools

The operational approach to software development is based on executable specifications and transformational implementation. PAISLey is an operational specification language intended to be the core of a method which is an instance of the operational approach, although only the initial (specification) phase of the method has been developed. This paper describes and evaluates the application of this method to the PAISLey implementation. Since PAISLey is intended for real-time systems and the application discussed here is in the area of programming environments, the method has obvious weaknesses as well as strengths.

A Conceptual Framework for the Design of Complex Automation Systems

Design methods and design tools have a crucial role in guaranteeing the quality of automation systems and man-machine interfaces. The abstract and often informal data that is generated during the early phases of the system design should be documented so that it can be easily used in later phases of the design work and also during plant operation. The System Modeling Language (SML) is one way to achieve this goal. The SML with its database system gives users the possibility to manipulate the complex data structures which are needed during the requirement analysis and functional specification phases of the design. The framework created by the formalism helps users to describe plant on different abstraction levels and also from different views. Also the goals and requirements of the plant can be managed more easily when they are stored into these descriptions.

A New Programming Methodology for Long-Lived Software Systems

A new software development methodology based on the language NIL is presented. The methodology emphasizes (1) the separation of program development into functional specification and tuning phases, (2) the use of a fully compilable and executable design, (3) an interface definition and verification mechanism. This approach reduces life-cycle costs and improves software quality because (a) errors are detected earlier, and (b) a single functional design can be re-used to produce many implementations.

The impact of rapid prototyping on specifying user requirements

Prototyping has been recognized as being a powerful and indeed essential tool in many branches of engineering. Although software prototyping is often considered too expensive, correcting ambiguities and misunderstandings at the requirements specification stage is significantly cheaper than correcting a system after it has gone into production. This paper describes how rapid prototyping impacts the Requirements Analysis and Specification phase of the software life cycle. This is illustrated by describing the experience gained from a prototype used to assist in the requirements specification of a system to manage and control an integrated circuit fabrication facility. The cost of the prototype was less than 10 percent of the total software development cost.

Rapid prototyping using executable requirements specifications

This paper describes a software tool, called the Feature Simulator, that "executes" formally written requirements specifications for real-time systems and enables users to "interact" with the simulated product at the completion of the requirements specification phase of the software life-cycle. This tool thus produces an early and rapid prototype with which customers, designers, and managers can verify that the product meets their needs and expectations. Any deficiencies that they find can then be corrected by inexpensive changes to the product's requirements specification, rather than by more costly modifications to the final product.

Bars — A dual bistatic auroral radar system for the study of electric fields in the Canadian sector of the auroral zone

One instrument of the Canadian Auroral Network for the Open Program Unified Study (CANOPUS) is a pulsed dual bistatic auroral radar system (BARS) for the mapping of ionospheric electric fields, using the STARE technique originated by R.A. Greenwald [14]. The Canadian system is presently in the specification and design phases, with the objective of being operational by mid-1984. This paper describes the geometry of the BARS system, the design considerations, and the planned data and control network.

Experience Of Teaching Debugging AndTesting

For most of the software engineering courses at the undergraduate levels, the emphasis is on the coding and pre-coding phases, that is, the phases of requirements analysis and specification, design as well as coding. The coverage of testing and maintenance is relatively superficial, despite of the fact that these two phases consume more resources than the others. One of the main reasons is that fewer methodologies in these two phases have been developed as compared with those in the other phases. Consequently, fewer literature on these areas appear in the undergraduate texts. Secondly, there is a lack of automated systems to support the teaching of these topics. However, the industry is now expecting to have a more thorough training for the computer science graduates in the areas of debugging and testing, as sound theoretical foundations and practical methodologies have been developed for debugging and testing in the past two decades. In response to the demands from the industry, some formal and advanced methods of debugging and testing are included in an undergraduate course given to the third year students at the University of Melbourne. In this paper, we are going to discuss the problems of teaching debugging and testing at the undergraduate levels. Transactions on Information and Communications Technologies vol 9, © 1994 WIT Press, www.witpress.com, ISSN 1743-3517 350 Software Quality Management

A Knowledge Based Design And Simulation ToolFor U-systems

Microsystems integrate electrical, mechanical and optical components on one single chip and wifl be a revolution in the next millennium. However, the design process of Microsystems is a historic challenge. An increasing need is perceived for simulation of the entire product or process at an early stage of the specification and design phase as part of the Concurrent Engineering approach. There exist also different approaches to integrate the parts into one single system, monolithic, hybrid or board integration. Therefore an integrated design tool is necessary, which takes all these facts into account and is at the same time very flexible.

Computer-Controlled Petroleum Production Systems

Use of computer control in the operation of production facilities has expanded rapidly in the past few years. Standard Oil Company of California completed its lastest such project, the automation of platforms Hope and Heidi in the Santa Barbara Channel, in mid 1967. The equipment, which uses an 8K computer control program together with a supervisory control system, permits unattended operation of the remote facilities. This paper discusses the project design details, startup, and operating history, emphasizing both hardware and software aspects of the system. Two unique operating routines, computed well-test sequences, and leak detection to test manifolds, are discussed in detail. Based on the Hope-Heidi experience and background from previous projects of a similar nature, the authors discuss their philosophy of automation. The needs for user and vendor coordination of their system responsibilities and thorough documentation are defined. Emphasis is placed on the advisability of forming a user hardware-software team to handle system engineering and programming "in-house." Particular importance is placed on the specification phase of a process-control project and the need to extract detailed technical data from the vendors in the bidding phase to ensure optimum and economic selection of a system to do a particular job. The discussion of software specifications and the concept of a user team to implement the project should prove useful to the oil producing industry. The concepts discussed are, however, applicable to the implementation of any industry's computer control program.