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The real-time process algebra (RTPA) is a set of new mathematical notations for formally describing system architectures, and static and dynamic behaviors. It is recognized that the specification of software behaviors is a three-dimensional problem known as: (i) mathematical operations, (ii) event/process timing, and (iii) memory manipulations. Conventional formal methods in software engineering were designed to describe the 1-D (type (0) or 2-D (types (i) and (iii)) static behaviors of software systems via logic, set and type theories. However, they are inadequate to address the 3-D problems in real-time systems. A new notation system that is capable to describe and specify the 3-D real-time behaviors, the real-time process algebra (RTPA), is developed in this paper to meet the fundamental requirements in software engineering. RTPA is designed as a coherent software engineering notation system and a formal engineering method for addressing the 3-D problems in software system specification, refinement, and implementation, particularly for real-time and embedded systems. In this paper, the RTPA meta-processes, algebraic relations, system architectural notations, and a set of fundamental primary and abstract data types are described. On the basis of the RTPA notations, a system specification method and a refinement scheme of RTPA are developed. Then, a case study on a telephone switching system is provided, which demonstrates the expressive power of RTPA on formal specification of both software system architectures and behaviors. RTPA elicits and models 32 algebraic notations, which are the common core of existing formal methods and modem programming languages. The extremely small set of formal notations has been proven sufficient for modeling and specifying real-time systems, their architecture, and static/dynamic behaviors in real-world software engineering environment. [ABSTRACT FROM AUTHOR]

A recent trend in software engineering is the shift from a focus on laboratory-oriented software engineering to a more industry-oriented view of software engineering processes. This complements preceding ideas about software engineering in terms of organization and process-orientation. From the domain coverage point of view, many of the existing software engineering approaches have mainly concentrated on the technical aspects of software development. Important areas of software engineering, such as the technical and organizational infrastructures, have been left untouched. As software systems increase in scales, issues of complexity and professional practices become involved. Software development as an academic or laboratory activity, has to engage with software development as a key industrialized process. This expanded domain of software engineering exposes the limitations of existing methodologies that often address only individual subdomains. There is, therefore, a demand for an overarching approach that provide a basis for theoretical and practical infrastructures capable of accommodating the whole range of modern software engineering practices and requirements. One approach is provided by Process-Based Software Engineering (PBSE); part of the more general trend towards a focus on process. This paper provides a review of process techniques for software engineering and a high-level perspective on PBSE. Typical approaches and techniques for the establishment, assessment, improvement and bench-marking of software engineering process systems are introduced in this paper, and many are developed further in other contributions to this volume. [ABSTRACT FROM AUTHOR]

Current practice in Web application development is based on the skills of the individual programmers and often does not apply the principles of software engineering. The increasing economic relevance and internal complexity of the new generation of Web applications require that proper quality standards are reached and that development is kept under control. It is therefore likely that the formalization of the process followed while developing these applications will be one of the major research topics. In this paper we focus on Web application testing, a crucial phase when quality and reliability are a goal. Testing is considered in the wider context of the whole development process, for which an incremental/iterative model is devised. The processes behind the testing activities are analyzed considering the specificity of Web applications, for which the availability of a reference model is shown to be particularly important. The approach proposed in this paper covers the integration testing phase, which can take advantage of some features of Web applications (e.g., the http protocol employed), thus resulting in a higher level of automation with respect to traditional software. The testing processes described in this paper are supported by the prototype research tool TestWeb. This tool exploits a reverse engineered UML (Unified Modeling Language) model of the Web application to generate and execute test cases, in order to satisfy the testing criteria selected by the user. The usage of this tool will be presented with reference to a real-world case study. [ABSTRACT FROM AUTHOR]

In this paper we propose Software Agents as a mediation support between the Internet and its users. The paper classifies mediation agents in three categories (Interface Agents, Coordination Agents, and Middle Agents) and provides examples of their usage in three application domains: Public Administration, Electronic Commerce, and Factory Automation. We then describe an agent-oriented mediation framework built on the Object Oriented Technology and we exemplify its usage with a case study in the domain of product negotiation on the Internet. [ABSTRACT FROM AUTHOR]

This paper introduces a generic and opened multi-agent platform that provides a powerful scientific equipment for collective research on self-organized systems. A general thought on the mutation of object model towards the agent model is presented. The paper details the construction of the platform upon generic models of environment and agent. Then we present the extension of the toolkit to web-based technologies, and its suitability for collective research and remote works. [ABSTRACT FROM AUTHOR]

The cost effective development of web applications is perhaps one of the most challenging areas of software engineering today. Not only are the problems to be solved, and the solution technologies to be used, in web application development among the most rapidly changing in the software industry, but the business pressures of cost, quality and time-to-market are among the most extreme. Web application development therefore has potentially the most to gain from software reuse approaches that can offer a greater return on development time than traditional approaches. However, simply combining ideas from these reuse paradigms and traditional web development technologies in ad-hoc ways will not result in sustainable improvements. In this paper we describe a systematic way of combining the benefits of component-based development and model driven architectures, two important reuse approaches, to support the cost effective development and maintenance of web applications. After first defining a suitably abstract component-model, the paper explains how component architectures can be systematically and rigorously modeled using UML. It then describes a powerful technique, known as stratification, for separating the various cross cutting aspects of a web application such that a suitable platform specific architecture can be traceably generated. Finally, the paper introduces a technique for increasing the trustworthiness of components by giving them the capability to check their deployment environment at run-time. [ABSTRACT FROM AUTHOR]

As a commonly acceptable standard for guiding Web markup documents, XML allows the Internet users to create multimedia documents of their preferred structures and share with other people. The creation of various multimedia document structures, typically as trees, implies that some kinds of conversion mechanisms are needed for people using different structures to understand each other. This paper presents a visual approach to the representation and validation of multimedia document structures specified in XML and transformation of one structure to another. The underlying theory of our approach is a context-sensitive graph grammar formalism. The paper demonstrates the conciseness and expressiveness of the graph grammar formalism. An example XML structure is provided and its graph grammar representation, validation and transformation to a multimedia representation are presented. [ABSTRACT FROM AUTHOR]

The term software engineering has had a problematic history since its appearance in the 1960s. At first seen as a euphemism for programming, it has now come to encompass a wide range of activities. At its core lies the desire of software developers to mimic 'real' engineers, and claim the status of an engineering discipline. Attempts to establish such a discipline, however, confront pressing commercial demands for cheap and timely software products. This paper briefly examines some of the claims for the engineering nature of software development, before moving to argue that the term 'engineering' itself carries with it some unwanted baggage. This contributes to the intellectual quandary in which software development finds itself, and this is exacerbated by many writers who rely upon and propagate a mythical view of 'engineering.' To complicate matters further, our understanding of software development is grounded in a series of metaphors that highlight some key aspects of the field, but push other important issues into the shadows. A rereading of Brooks' “No Silver Bullet” paper indicates that the metaphorical bases of software development have been recognized for some time. They cannot simply be jettisoned, but perhaps they need widening to incorporate others such as Brooks' concepts of growth and nurture of software. Two examples illustrate the role played by metaphor in software development, and the paper concludes with the idea that perhaps we need to adopt a more critical stance to the 'engineering' roots of our endeavours. [ABSTRACT FROM AUTHOR]

Conceptual modelling is situated in the broader view of information systems requirements engineering. Requirements Engineering (RE) explores the objectives of different stakeholders and the activities carried out by them to meet these objectives in order to derive purposeful system requirements and therefore lead to better quality systems, i.e., systems that meet the requirements of their users. Thus RE product models use concepts for modelling these instead of concepts like data, process, events, etc., used in conceptual models. Since the former are more stable than the latter, requirements engineering manages change better. The paper gives the rationale for extending traditional conceptual models and introduces some RE product models. Furthermore, in contrast to conceptual modelling, requirements engineering lays great stress on the engineering process employed. The paper introduces some RE process models and considers their effect on tool support. [ABSTRACT FROM AUTHOR]

Engineering is a set of disciplines seeking solutions for complicated problems and systems that could not be done by individuals. The aim of engineering is to repetitively produce complicated artefacts in an efficient way. This paper describes a set of generic engineering principles and an engineering maturity model. With the engineering principles and model, the nature and status of software engineering are analysed. Interesting findings on what software engineering can learn from generic engineering principles are presented. This paper intends to show the nature, status and problems of software engineering, as well as its future trends, based on the comparative studies between the generic engineering principles and software engineering practices. [ABSTRACT FROM AUTHOR]

In real-time systems, dynamic inconsistencies of software are hardly detected, diagnosed and handled. A built-in test (BIT) method is developed to cope with software dynamic inconsistency. BIT is defined as a new kind of software testing which is explicitly described in object-oriented source code as member functions. BITs can be activated at any designed moment at run-time to detect, diagnose and handle software dynamic inconsistencies. This paper develops a new approach to cope with software dynamic inconsistencies at run-time by BITs. In this paper, the concept of BITs is introduced. The standard structures which incorporate BITs into conventional object-oriented software are analysed. Reuse methodologies for BITs in OO software are developed at object and system levels. A case study is provided for showing how to create BIT and how to inherit and reuse BITs in OO programming. Methods for incorporating BITs into OO software at object, class and system levels are provided. An approach to dynamic inconsistency control by BITs is developed. [ABSTRACT FROM AUTHOR]

This paper describes a methodology for the specification and analysis of distributed real-time systems using the toolset called PARAGON. PARAGON is based on the Communicating Shared Resources paradigm, which allows a real-time system to be modeled as a set of communicating processes that compete for shared resources. PARAGON supports both visual and textual languages for describing real-time systems. It offers automatic analysis based on state space exploration as well as user-directed simulation. Our experience with using PARAGON in several case studies resulted in a methodology that includes design patterns and abstraction heuristics, as well as an overall process. This paper briefly overviews the communicating shared resource paradigm and its toolset PARAGON, including the textual and visual specification languages. The paper then describes our methodology with special emphasis on heuristics that can be used in PARAGON to reduce the state space. To illustrate the methodology, we use examples from a real-life system case study. [ABSTRACT FROM AUTHOR]

This paper analyses current principles of software development: from domains via requirements to design. On the basis of this analysis we outline a structure and contents of professional software engineering. From this we extract some requirements to a university graduate (M.Sc.) curriculum in software engineering. We summarise the four software engineering axes that we wish to emphasize in this paper: • software engineering as a responsible profession, • abstraction, linguistics and logic, • methodology, formal specification and design calculi, • domain, requirements and software design engineering. We view (i) engineering as ‘walking the bridge between science and technology’ – with engineers using mathematics as and when appropriate, (ii) methods as ‘sets of principles for analysing problems and for selecting and applying techniques and tools in order to efficiently construct an efficient artifact (here software),’ and (iii) software engineering as consisting of ‘domain engineering, requirements engineering and software design (engineering)’ – with software development comprising all these stages and teams of engineers specially educated in sub-branches of software engineering. Since software engineering produces and consumes descriptions and since professional engineers create varieties of abstractions we conclude that they make use of varieties of formal specification languages and design calculi – to represent abstract and concrete descriptions and to calculate over and between these. The paper may be incomplete in not covering aspects of AI and knowledge based engineering. It also does not deal with the dimensioning and performance evaluation of hardware and software systems. The paper, in its attempt at a comprehensive analysis and proposal, is long. Our analysis subsumes that of ACM and IEEE [ACM/IEEE-CS June 1991] to which we add! [ABSTRACT FROM AUTHOR]

This paper presents work that has been done in bringing patterns and pattern languages into undergraduate and postgraduate curricula in software engineering. Patterns are masterful designs that solve a real problem; they provide students with real, concrete examples of best practises and masterful software solutions they can utilize and emulate. A pattern language is a modular and adaptive methodology; it is appropriate for the dynamic discipline of software engineering. The paper outlines aspects of a curriculum used at the Royal Melbourne Institute of Technology; it also provides student and staff feedback. [ABSTRACT FROM AUTHOR]

One of the most intractable problems in software is getting engineers to consistently use effective methods. The Software Engineering Institute (SEI) has worked on this problem for a number of years and has developed effective methods for addressing it. This paper describes these methods and shows what they have accomplished with several hundred students and working engineers. After first describing the problem of changing engineers' practices, the paper discusses the logic engineers typically follow in deciding what methods to use. Next is a description of the Personal Software Process (PSP) and the Team Software Process (TSP). Finally, the implications of SEI's experiences with the PSP and TSP are described, with particular emphasis on software engineering and computer science education. [ABSTRACT FROM AUTHOR]

This paper describes the development of an undergraduate degree programme in software engineering over the ten year period from 1988 to 1998. Particular emphasis is given to the fundamental principles that have been established to guide the creation and evolution of this programme during this period, and to ensure that it has been distinctively a course in software engineering rather than in any other branch of computing. To this end, the fundamental engineering characteristics of the programme are compared with those of undergraduate courses in other branches of engineering. Desirable future developments in this programme are then discussed, and finally the different principles identified in the paper are evaluated. [ABSTRACT FROM AUTHOR]

Software quality involves the conformance of a software product to some predefined set of functional requirements at a specified level of quality. The software is considered valid when it conforms to these "quality factors" at some acceptable level. There are a large number of quality factors against which software may he validated. This paper discusses the development of traditional software metrics in relation to the anticipated structure of a software system. The taxonomy of a software system primarily relies upon the dissection of the software system into modules. Modular design is the cornerstone of quality software, and metrics that can predict an optimum modular structure are critical. By examining the theoretical bases on quality metrics, a base set of common quantitative metrics can be devised and mapped to quality metrics in which they reside. This paper surveys existing metrics and suggests the derivation of software design metrics from software quality factors. Measurable software attributes are identified and suggested as potential design metrics. [ABSTRACT FROM AUTHOR]

This paper describes empirical research into Internet software development practices. The focus of our study is to develop an understanding of the features that characterize Internet software development. Based on a Grounded Theory analysis of data collected in nine US software development organizations, we identify three factors that influence Internet software development processes: demand for rush to market, operating in a different kind of market environment and the lack of experience developing such products. Though many of the characteristics of the development processes identified in our study may be observed in traditional software development, the intensity with which they apply and together distinguish Internet software development. The differences include a distinct collection of methods, tools, and management techniques for software engineering, and embody a unique development culture and negotiable software quality. [ABSTRACT FROM AUTHOR]

Process Centered Environments (PCEs) are the most recent generation of environments supporting the software engineering process. They aim to drive and assist developpers in the application of software development methods, by exploiting an explicit representation of the process. Several PCEs have been developped, both as research project and commercial products. This paper makes a point of research works and research challenges. It identifies 8 PCEs and a list of general requirements selected regarding actual software process technology needs along with some PCEs experiments results. A set of comparison criteria is then established and a list of open issues, derived from PCEs comparison, is presented. [ABSTRACT FROM AUTHOR]

The original idea of the World Wide Web was to create a universe of network-accessible information. Since its inception, the World Wide Web has evolved from a means to help people access and use information into an interactive medium. This has caused a dramatic increase in the development effort for interactive services, which now have to support multiple clients with widely varying computing and user interface capabilities. Personalization features tend to render this task even more complex. The paper presents the MUSA (Multiple User Interfaces, Single Application) system, which addresses both issues with the introduction of an event graph that abstracts user interface and personalization issues from the implementation of the service on different client-devices. [ABSTRACT FROM AUTHOR]

The Web now offers an exceptional infrastructure for the development of distributed collaborative services and applications. However, most of the existing applications only make use of the Web access and visualization facilities, without exploiting its distributed-processing potential capabilities. Web technologies are currently more focused on the provision of semantics to data and the design of dynamic Web pages, while paying little attention to the distributed architecture of the applications - that should go beyond client-server architectures. Application frameworks are one of the key technologies that may provide the mechanisms required for the design and development of reusable and scalable systems in these environments. However, the way to document such frameworks so they can be effectively tailored and reused still remains unresolved. In this paper we propose the use of UML profiles for documenting Web-based application frameworks, as a standard means for expressing their semantics. UML profiles allow all stakeholders of a system to share a common graphical notation and vocabulary, and permit more precise specifications and better documentation on how to use and customize applications. As an example, we build a UML profile for MultiTEL, a framework particularly well suited for the development of Internet-based multimedia and collaborative systems, and show how systems designers can use it to derive and document their applications. [ABSTRACT FROM AUTHOR]

The success of building distributed object systems depends on important factors such as architecture, the distributed object model (DOM) selected, and the process adapted in the selection of the DOM. There are a number of DOMs. Although the primary goals of these models are the same, each model has a unique underlying architecture, maturity, and features provided. A critical evaluation of DOMs is thus needed by those organizations that are considering migrating to distributed object computing. The evaluation process can be time-consuming and may drain organizational resources. Most of the current evaluation processes adopted by organizations are not generic enough, and they concentrate only on the problem on hand. Hence, they cannot be used by any other organization, sometimes not even a different project at the same organization. Therefore, a more generalized framework or template is required to evaluate DOMs. This paper proposes a framework to evaluate DOMs. A number of important managerial items such as cost, personnel, and technology resources, training, enterprise changes, and time constraints have been identified, explained, and justified as the evaluation criteria. An evaluation of the most widely used DOMs, CORBA, DCOM, and RMI, is provided using the above criteria. Finally, a case study of a production web-based system is presented to demonstrate the use of the framework. [ABSTRACT FROM AUTHOR]

Software development is a product of evolution. It builds on the experiences of the individual and the community, continually refining every aspect of process. Web centric architectures are no different. Their ever-increasing levels of functionality and complexity are evident in the latest generations of web applications. In this paper we discuss some standards that enable teams to build, communicate and apply their experiences in the art of web application software development. These standards appropriate various levels of abstraction, and bring the focus of web application development back to the team. Combining UML representation of web-based systems with techniques for packaging these solutions for reuse can positively impact development timelines and efficiencies. [ABSTRACT FROM AUTHOR]

Separation of concerns is a well-established principle in software engineering that supports reuse by hiding complexity through abstraction mechanisms. The Abstract Design Views model was created with reuse in mind and allows the designer to apply separation of concerns in a software system from the design to the implementation. In this model, viewed objects represent the basic concern, i.e., the algorithms that provide the essential functionality relevant to an application domain, and viewer objects represent the special concerns related to other software issues, such as user interface presentation, synchronization, and timing. In this paper we use a reuse taxonomy to analyze and validate this model. Using this analysis and the properties of the relationship between viewer and viewed objects, called "views," we also indicate how to map the views-based designs into implementations based on design patterns that satisfy the views properties. Finally, we show how to apply the principles of our approach, using views and the design patterns, to design c-commerce applications. [ABSTRACT FROM AUTHOR]

In this paper, we discuss different object-oriented design structures that should be used in the process of building Web applications. We base our discussion on the OOHDM approach for defining a Web application model, in particular, the separation of the navigational model from the conceptual model. We focus on the systematic application of different design patterns (such as Observer and Decorator) for decoupling different aspects of a Web model. We briefly discuss some specific patterns that may appear in this kind of applications and we introduce additional concepts such as Web frameworks as a conceptual approach to maximize design reuse in Web applications. [ABSTRACT FROM AUTHOR]

Web applications can be classified as hybrids between hypermedia and information systems. They have a relatively simple distributed architecture from the user viewpoint, but a complex dynamic architecture from the designer viewpoint. They need to respond to operation by an unlimited number of heterogeneously skilled users, address security and privacy concerns, access heterogeneous, up-to-date information sources, and exhibit dynamic behaviors that involve such processes as code transferring. Common system development methods can model some of these aspects, but none of them is sufficient to specify the large spectrum of Web application concepts and requirements. This paper introduces OPM/Web, an extension to the Object-Process Methodology (OPM) that satisfies the functional, structural and behavioral Web-based information system requirements. The main extensions of OPM/Web are adding properties of links to express requirements, such as those related to encryption; extending the zooming and unfolding facilities to increase modularity; cleanly separating declarations and instances of code to model code transferring; and adding global data integrity and control constraints to express dependence or temporal relations among (physically) separate modules. We present a case study that helps evaluate OPM/Web and compare it to an extension of the Unified Modeling Language (UML) for the Web application domain. [ABSTRACT FROM AUTHOR]

The Tatami project is building a system to support software engineering over the internet, exploiting recent advances in Web technology, interface design, and specification. Our effort to improve the usability of such systems has led us into algebraic semiotics, while our effort to develop better formal methods for distributed concurrent systems has led us into hidden algebra and fuzzy logic. This paper discusses the Tatami system design, especially its software architecture, and its user interface principles. New work in the latter area includes an extension of algebraic semiotics to dynamic multimedia interfaces, and integrating Gibsonian affordances with algebraic semiotics. [ABSTRACT FROM AUTHOR]

As object-oriented analysis and design techniques mature, the promises of object-orientation become more realizable. The advent of multimedia hardware and software technology give rise to a need for generalized multimedia data access methods. This paper describes the object-oriented development and subsequent maintenance of ENFORMS, an object-oriented distributed multimedia information system. We discuss the advantages and disadvantages of using object-oriented analysis and design techniques to develop a general client–server architecture for browsing, retrieving, and analyzing distributed multimedia data. We also describe lessons learned from this project, including the impact of a rigorous application of object-oriented analysis and design techniques. [ABSTRACT FROM AUTHOR]

The World Wide Web (WWW) is now accepted as a de facto standard for human–computer interaction and human–human communication, so it is desirable to develop net-centric, multimedia and collaborative applications. In this paper, we present a new scripting language, JACIE, designed to support rapid prototyping and implementation of such applications. The support for the management of multimedia interaction and communication in collaborative applications is highlighted. JACIE facilitates such support through the concepts of channels and a collection of interaction protocols. A template-based programming style is adopted by JACIE, using a single program for both client and server, and platform-independence achieved by employing Java as the target language. All these features characterise a desirable multimedia software engineering tool. [ABSTRACT FROM AUTHOR]

Domain specific techniques take advantage of the commonalities among applications developed within a certain domain. They are known to improve quality and productivity by incorporating domain knowledge and previous project experiences and promote reuse. This paper describes six domain specific software engineering techniques for developing multimedia applications within the digital library domain. We provide examples of each technique from several projects in which they were used, how the techniques are used within general software engineering practice (in particular, MBASE), how the techniques address some of the particular challenges multimedia software engineering, and the positive impacts we have measured resulting from their use within a graduate level software engineering course. [ABSTRACT FROM AUTHOR]

Negotiating stakeholder WinWin relationships among software quality requirements is a technique that emerged during the 1990's in order to overcome the difficulties arising from contract-oriented specification compliance (popular in the 1970's) and service-oriented customer satisfaction (popular in the 1980's). Obstacles to adoption of negotiated win-win relationships include coordination of multiple stake- holder interests and priorities, reasoning of complicated dependencies, and scalability of an exponentially increasing resolution option space. Conflict identification and resolution techniques are key success factors to overcome the obstacles. This paper describes two exploratory knowledge-based tools (called "QARCC" and "S-COST")* for conflict identification and resolution and how they were used in the digital library projects of a USC Software Engineering class during the 1996/97 school year. A comparative analysis with the artifacts surfaced by stakeholders and the artifacts generated and analyzed by QARCC and S-COST focused on the conflict resolution process, stakeholders' roles and their relationships to quality artifacts, and tool effectiveness. We conclude that the tools helped stakeholders: (1) surface and negotiate conflicts; (2) identify conflicts among functional and quality requirements; and (3) generate, visualize, and negotiate potential resolution options for the conflicts. [ABSTRACT FROM AUTHOR]

When first formulated in the early seventies, the laws of software evolution were, for a number of reasons, not widely accepted as relevant to software engineering practice. Over the years, however, they have gradually become recognised as providing useful inputs to understanding of the software process. Now eight in number, they have been supplemented by the software uncertainty principle and the FEAST (Feedback, Evolution And Software Technology) hypothesis. Based on all these and on the further results of the FEAST research projects this paper develops and presents some fifty rules for application in software system process planning and management and indicates tools available or that could usefully be developed to support their application. The listing is structured according to the laws that encapsulate the observed phenomena and that lead to the recommendations. Each sublist is preceded by a textual discussion providing at least some of the reasoning that has led to the recommended procedures. The references direct the interested reader to the literature that records observed behaviours, interpretations, models and metrics obtained from industrially evolved systems, and from which the recommendations were derived. [ABSTRACT FROM AUTHOR]

As software technologies advance, the software community uses the newest and most powerful technology and associated notations. However, mapping software with a set of notations that would survive the test of time is becoming increasingly difficult. A survey of current methodologies indicates that half-lives of various software notations are short. The dependence of software notations on programming languages and environment specific methodologies often makes these notations obsolete. In this paper, development of a standard set of software notations that is independent of programming paradigms, yet extensible enough to accommodate programming needs, is proposed. [ABSTRACT FROM AUTHOR]

In many mature engineering disciplines, reuse of available design knowledge is helped by the presence of handbooks. These handbooks record the details of existing system components and help in the process of evaluating design alternatives while building new systems. In recent times, design patterns have been identified as fundamental components of an object oriented design. However, they are presented in a format that may not be best suited for systematic selection and use while evaluating design alternatives. This paper provides a procedure to construct a handbook based on design patterns. This handbook helps designers in methodical selection of design patterns. The construction of the handbook is based on the identification of a set of key attributes of a design pattern and quantification of these attributes using the principles of measurement theory. A new methodology for object oriented design which consults the handbook during the design process is also introduced. The proposed methodology along with the handbook helps in evaluating different design alternatives. [ABSTRACT FROM AUTHOR]

With the rapid growth of network computing, the demand for large-scale and complex software systems has increased dramatically. However, the development of large-scale and complex software systems is much more difficult and error prone. This is due to the fact that techniques and tools for assuring the correctness and reliability of software systems lag far behind the increasing growth in size and complexity of software systems. The concept of software architecture has recently emerged as a new way to improve our ability to effectively construct and maintain large-scale complex software systems. The architecture based development of software systems focuses on the architectural elements and their overall interconnection structure. Several Architectural Definition Languages (ADLs) have been proposed for specifying domain specific or general purpose architectures. On the other hand, formal verification is rapidly becoming a promising and automated method to ensure the accuracy and correctness of software systems. In this paper, we survey several architecture description languages and formal verification methods. We present an environment to conduct experiments to study the performance of five different verification tools on software architecture specifications. Based on these experiments, we are able to compare the efficiency of these verification tools in verifying certain software property. [ABSTRACT FROM AUTHOR]

Technical issues are important for software work, but so are personal disciplines, team-working skills, and application-domain knowledge. Also, much like an artistic performance, first-class software engineering requires constant practice, good technique, and effective coaching. The challenge of producing high-quality large-scale software products is substantial today and will be even more demanding in the future. Without concerted action, we cannot expect software organizations' capabilities to improve. To address these problems, the Software Engineering Institute (SEI) has developed the Personal Software Process (PSP) and the Team Software Process (TSP). This paper addresses the problems of software engineering and discusses the intellectual nature of software work. It then reviews the characteristics of this kind of work and describes the principal conditions for effective software performance. In the conclusion, the author makes some observations about the challenges ahead and the future actions required. [ABSTRACT FROM AUTHOR]

The contribution of this paper is three empirical evaluations of a reference model for the practice of software reuse. Our research thesis is that software development based upon a software reuse reference model improves quality of products, productivity of processes and product time-to-market for many software development enterprises. The definition and investigation of such a model has been carried out using three steps. First, the reference model is developed based on existing software reuse concepts. Second, this reference model is empirically evaluated using three studies: one using a survey method, one using a case studies method, and one using a legacy studies method. Third, the impact of the reference model on software development productivity, quality, and time-to-market is empirically derived. [ABSTRACT FROM AUTHOR]

This paper summarizes several classes of software cost estimation models and techniques: parametric models, expertise-based techniques, learning-oriented techniques, dynamicsbased models, regression-based models, and composite-Bayesian techniques for integrating expertise-based and regression-based models. Experience to date indicates that neural-net and dynamics-based techniques are less mature than the other classes of techniques, but that all classes of techniques are challenged by the rapid pace of change in software technology. The primary conclusion is that no single technique is best for all situations, and that a careful comparison of the results of several approaches is most likely to produce realistic estimates. [ABSTRACT FROM AUTHOR]

Today's digital systems are growing increasingly complex, and are being used in increasingly critical functions. The first premise makes them more prone to contain faults, and the second premise makes their failure less tolerable. This widening gap highlights the need for fault tolerant techniques, which make provisions for reliable operation of digital systems despite the presence and occasional manifestation of faults. In this paper we present a brief comparative survey of fault tolerance as it arises in hardware systems and software systems. We discuss logical models as well as statistical models of fault tolerance, and use these models to analyze design tradeoffs of fault tolerant systems. [ABSTRACT FROM AUTHOR]

Object modelling languages are graphical semi-formal specification languages. They are tools to capture and formalise requirements in the earlier phases of software development, as well as providing support for describing designs, software architecture and even detailed implementations later in the process. One can consider these languages to have reached some level of maturity, especially because their precursors, the Object-Oriented Analysis and Design methods, have now been used and tested intensively in industry for many years. In addition, these modelling languages have been the subject of many improvements by the scientific community. Nevertheless, some dissatisfaction persists. In this paper, we aim to re-analyse several parts of the deep structure of two leading object modelling languages: OML and UML, in order to show how they can really increase software quality. Their structure is based on metamodelling, which is the way the semantics of these two languages is expressed. This structure is also the source of a proliferation of modelling constructs (for example, different forms of inheritance associated with distinct notational elements) whose use must clearly influence, in particular, reusability - a key expectation in a software engineering process. More generally, we identify some deficiencies in these languages, which allows us to highlight some appropriate evolutionary paths. In discussing dynamic metamodelling and scalability, we specifically outline that a main current drawback is the difficulty of implementing these languages in Computer-Aided Software Engineering tools. [ABSTRACT FROM AUTHOR]

In this invited paper we review 25 years of propagating formal specification in software engineering. We will do so through outlining a paradigmatic approach to the practice of software engineering. For the sake of contrasting argument we shall claim that this approach stands in sharp contrast to classical engineering – and that there is little help to be obtained from classical engineering in securing the quality of the most important facets of software engineering! We shall be outlining a software engineering practice in which formal techniques are applied in capturing the application domain void of any reference to requirements let alone software; and in then capturing requirements: Domain requirements (projected, instantiated, possibly extended and usually initialised from domain descriptions), interface requirements and machine requirements. The software engineering practice then goes on to design the software: First the architecture, then the program structure, etc. Throughout abstraction and modelling, hand-in-hand, are used in applicative (functional), imperative and process oriented descriptions, from loose specifications towards concrete, instantiated descriptions, using hierarchical as well as configurational modelling, denotational as well as computational modelling, and in structuring even small scale descriptions using appropriate modularisation concepts: Schemes, classes and objects. All the concepts spelled in this font are software engineering “program” description notions that have been honed over the years, starting in 1973 with VDM [Bekić et al. 1974; Bjørner and Jones 1978, 1982b] and continuing with RAISE [Group 1992, 1995]. The current status of our approach to software engineering, based on extensive, but not exclusive use of formal techniques, developed significantly during my years as UN Director of the UN University's International Institute for Software Technology (UNU/IIST) in Macau, 1992-1997. Many large scale software developments based on the domain/requirements/software design paradigm outlined here were systematically applied to the experimental development of software designs for the computing support of a number of diverse infrastructure components2 . Special boxes, scattered throughout the text, highlight 'pinnacle' contribution by named computer and computing scientists as well as by specific R&D projects. [ABSTRACT FROM AUTHOR]

This paper investigates implementations of process algebras which are suitable for modeling concurrent real-time systems. It suggests an approach for efficiently implementing real-time semantics using dynamic priorities. For this purpose a process algebra with dynamic priority is defined, whose semantics corresponds one-to-one to traditional real-time semantics. The advantage of the dynamic-priority approach is that it drastically reduces the state-space sizes of the systems in question while preserving all properties of their functional and real-time behavior. The utility of the technique is demonstrated by a case study that deals with the formal modeling and verification of several aspects of the widely-used SCSI-2 bus-protocol. The case study is carried out in the Concurrency Workbench of North Carolina, an automated verification tool in which the process algebra with dynamic priority is implemented. It turns out that the state space of the bus-protocol model is about an order of magnitude smaller than the one resulting from real-time semantics. The accuracy of the model is proved by applying model checking for verifying several mandatory properties of the bus protocol. [ABSTRACT FROM AUTHOR]

ASTRAL is a formal specification language for real-time systems. It is intended to support formal software development and, therefore, has been formally defined. The structuring mechanisms in ASTRAL allow one to build modularized specifications of complex systems with layering. A real-time system is modeled by a collection of state machine specifications and a single global specification. This paper discusses the ASTRAL Software Development Environment (SDE), which is an integrated set of design and analysis tools based on the ASTRAL formal framework. The tools that make up the support environment are a syntax-directed editor, a specification processor, a verification condition generator, a browser kit, a model checker, and a mechanical theorem prover. [ABSTRACT FROM AUTHOR]

Developing and maintaining large-scale software systems is very expensive. The concept of software architecture has recently emerged as a way to support the evolution of large-scale software systems. Several architecture description languages (ADLs) have been proposed to support the specification of software architectures. However, current ADLs do not provide strong support for the analysis of software architecture properties. On the other hand, various analysis tools have been developed for system analysis in the formal verification community. In this paper, we make two contributions. First, for the tools which are applicable to the property analysis of software architectures, we establish a connection between different analysis tools and the software systems modeled by architecture description languages. Second, we conduct experiments to study the performance of four different analysis tools in detecting deadlocks. Based on these experiments, we are able to compare the efficiency of these analysis tools in verifying certain software properties. [ABSTRACT FROM AUTHOR]

In this paper we describe and review the course plan and syllabus we use in a course on formal methods in software engineering currently included in the degree in Informatics of the Faculty of Sciences at the University of Bologna. The course matches the theory of formal methods with their practice based on actual tool usage. In fact, the course is centered upon a project whose main goal is to let students learn some formal specification techniques, all supported by specific tools. The students use well-known notations for both requirements specification and formal design. The formal methods we use are based on the Z notation for requirements specification and on the Larch family of languages for design specifications. [ABSTRACT FROM AUTHOR]

A project course in software engineering is often part of the curriculum in computer engineering or computer science. This paper studies the relationship between academic and industrial projects in software engineering. The purpose is to compare the practices followed in a project-course approach with the practices of professional software engineers. The approach is to compare the measurements obtained from academic and industrial projects. The critical factors regarding the process, the people and the project are discussed. The structure of the software processes and the measurement tools are presented. The data analyses show that the academic projects are found to be strongly dominated by programming activities. Based on the data from the industrial projects, we formulate seven recommendations to improve the software engineering practices in academic projects. They are related to management, predevelopment, development, testing, reviews documentation and team activities. The concluding remarks discuss some of the actions that could be taken to improve academic projects. [ABSTRACT FROM AUTHOR]

We have been applying the stakeholder win–win approach to software engineering education. The key stakeholders we are trying to simultaneously satisfy are the students; the industry recipients of our graduates; the software engineering community as parties interested in improved practices; and ourselves as instructors and teaching assistants. In order to satisfy the objectives or win conditions of these stakeholders, we have formed a strategic alliance with the USC Libraries to have software engineering student teams work with Library clients to define, develop, and transition USC digital library applications into operational use. This adds another set of key stakeholders: the Library clients of our class projects. This paper summarizes our experience in developing, conducting, and iterating the course. It concludes by evaluating the degree to which we have been able to meet the stakeholder-determined course objectives. [ABSTRACT FROM AUTHOR]

Software engineering is entering the educational mainstream at a time when budgets are tight, growth opportunities are limited, and existing disciplines are fighting to retain their share of a shrinking educational pie. This paper discusses some of the fundamental reasons why this situation is not likely to improve, and addresses ways software engineering can utilize modern computing and communication technology to overcome these limitations and, indeed, to lead the way in innovative education. [ABSTRACT FROM AUTHOR]

This paper describes how we have modified a software engineering stream within a computer science course to include broader concepts of systems engineering. We justify this inclusion by showing how many reported problems with large systems are not just software problems but relate to system issues such as hardware and operational processes. We describe what we mean by ‘systems engineering’ and go on to discuss the particular course structure which we have developed. We explain, in some detail, the contents of two specific systems engineering courses (Software Intensive Systems Engineering and Critical Systems Engineering) and discuss the problems and challenges we have faced in making these changes. In the appendix, we provide details of the case studies which are used as linking themes in our courses. [ABSTRACT FROM AUTHOR]

The issues associated with the accreditation, certification, and licensure of software engineers are, or at least should be, of great concern to the software engineering community. Perhaps as a result of publicity about safety-critical software disasters in the news media, some state legislatures have considered regulating the practice of software engineering, and some professionals believe that accreditation, certification, and licensure are inevitable. Yet there is no agreed-upon body of knowledge for software engineering on which to base accreditation, certification, or licensure, which makes implementing them difficult at best. In addition, it is not clear that these processes and possible mechanisms to support them are well understood within the software engineering community. This paper surveys how these three processes are conducted in other professions, summarizes the processes as they currently exist for computing in general, identifies some issues that are involved in implementing the processes for software engineering, and suggests possible actions that can be taken by the software engineering profession. The implications of accreditation, certification, and licensure for education are also discussed. [ABSTRACT FROM AUTHOR]