Vol.1 No.1 October, 2002

Editorial (ppi-ii)
          Managing Editors
In This Issue (pp1-2)
          Y. Deshpande
Research Articles and Reviews:
Web Engineering (pp003-017)
      Y. Deshpande, S. Murugesan, A. Ginige, S. Hansen, D. Schwabe, M. Gaedke, and B. White
Web Engineering is the application of a systematic, disciplined and quantifiable approach to development, operation, and maintenance of Web-based applications.  It is both a pro-active approach and a growing collection of theoretical and empirical research in Web application development. This paper gives an overview of Web Engineering by addressing the questions: a) why is it needed?  b) what is its domain of operation? c) how does it help and what should it do to improve Web application development? and d) how should it be incorporated in education and training? The paper discusses the significant differences that exist between Web applications and conventional software, the taxonomy of Web applications, the progress made so far and the research issues and experience of creating a specialisation at the master's level. The paper reaches a conclusion that Web Engineering at this stage is a moving target since Web technologies are constantly evolving, making new types of applications possible, which in turn may require innovations in how they are built, deployed and maintained.

A Proposed Curriculum for a Masters in Web Engineering (pp018-022)
      E. J. Whitehead
To address the significant technical demand for trained Web Engineers, and to raise the current state of the practice of Web Engineering, a Master’s level degree program in Web Engineering is proposed. The most significant research disciplines for Web Engineering are Network Engineering, Software Engineering, Databases and Storage Systems, and Hypermedia. Important aspects of these disciplines are distilled into key knowledge areas for Web Engineering. A curriculum organization is proposed that consists of coursework that covers the key knowledge areas, along with a multi-semester Web design project that synthesizes and applies this knowledge on a real-world Web application. The aim of the paper is to begin a dialog on the characteristics and aims of graduate-level Web Engineering degree programs.

Client Needs and the Design Process in Web Projects (pp023-036)
      D. Lowe and J. Eklund
The nature of Web systems is substantially different from more conventional software systems. They are developed in shorter timeframes, often act as the direct interface between multiple stakeholders, meet a more generic set of requirements, and generally serve a less specific user group. They are often developed very quickly from templated solutions, using coarse-grained authoring tools, and by the efforts of a multi-disciplinary team. There is often considerable uncertainty on the part of the client as to their own requirements. The importance of defining the objectives of the system during the early stages of a project are generally acknowledged to be important, but access to the tools and templates can encourage developers to build too early. Often requirements are inadequately documented, or only emerge during development, or change as development proceeds. The immaturity of the industry and the lack of standardised processes in web development have been demonstrated by web-based solutions that in many cases fail to meet fundamental requirements. Specifications for Web systems are consequently very different from those for more conventional software systems. Apart from an increased emphasis on user interactions and the underpinning content, they also reflect a blurring of the boundaries between requirements, specifications and designs in the development process.   In this paper we offer an iterative model for Web systems development that incorporates the user of partial design prototypes as a crucial stage in resolving requirements. This is derived from an analysis of the results of a survey of commercial Web practice. In particular, we explore what this data tells us about the nature of Web specifications, particularly looking at what is typically specified and the stage at which certain characteristics emerge within the evolving specification. The results support the hypothesis that within commercial Web development, design artifacts become a crucial element in supporting client understanding and driving the formulation of requirements.

A Software Architecture for Structuring Complex Web Applications (pp037-060)
      M. D. Jacyntho, D. Schwabe, and G. Rossi
In this paper we present an architecture for building families of rich Web applications. We first characterize current trends in Web applications, from read-only Web sites to sophisticated applications where complex distributed transactions must be supported. We next some design principles for building Web applications, and give the rationale for separating application behavior from navigation and interface issues. We briefly argue the need for developing a product line architecture for simplifying the systematic construction of different families of applications. We next describe the main components of our architecture explaining how we manage to decouple application specific aspects from technological aspects (such as dynamic page generation and persistence) that can be eventually solved by reusing of-the-shelf components. We show how to build application frameworks using this architecture using a concrete example of an electronic CD store.

Towards a Reusable Repository for Web Metrics (pp061-073)
      L. Olsina, G. Lafuente, and O. Pastor
In this article we introduce a metric model as one of the building blocks for a repository of metrics. Particularly, starting from a conceptual model for metrics, we thoroughly discuss a catalogue template for product metrics instantiating it with some Web metrics.  A catalogue of metrics basically allows tools, evaluators and other stakeholders to have a service and a consultation mechanism, which starts from a sound specification of the entity type, the attribute definition and motivation, the metric formula, criteria and protocols, among other template items. The metrics repository and the cataloguing tool can be appropriately used to support different quality assurance processes such as non-functional requirements specification, quality testing definition, etc. in different phases of the software life cycle. Effective and full-fledged quality assurance processes require not only strategic but also technological support as well.

Characterizing E-business Workloads Using Fractal Methods (pp074-090)
        D. Menasce, B. Abarahao, D Barbara, V. Almeida, and F. Ribeiro
Understanding the workload of Web and e-business sites is a fundamental step in sizing the IT infrastructure that supports these sites and in planning for their evolution so that Quality of Service (QoS) goals are met within cost constraints. This paper presents two approaches for characterizing e-business sessions: distance-based and fractal (session similarity). We apply both approaches to an actual e-business workload to understand what customers do, what navigational patterns they follow, and to identify groups of users that have similar behavior. We also present the benefits and drawbacks of both approaches. The main contribution of this work is the presentation of techniques that improve the process of workload characterization.

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