Strudel is a system for implementing data-intensive Web sites, which typically integrate information from multiple data sources and have complex structure. Strudel's key idea is separating the management of a Web site's data, the specification of its content and structure, and the visual representation of its pages. Strudel provides a declarative query language for specifying a site's content and structure, and a simple template language for specifying a site's HTML representation. This paper contains a comprehensive description of the Strudel system and details the benefits of declarative site specification. We describe our experiences using Strudel in a production application and describe three different, but complementary, systems that extend and improve upon Strudel's original ideas. Key words Web-site management, declarative query languages 1 Introduction Web sites have become the principal mechanism for disseminating and accessing information on the Internet and on corporation...

Web sites are progressively evolving from browsable, read-only information repositories to web-based distributed applications. Compared to traditional web sites, these web applications do not only support navigation and browsing, but also operations that have affects their contents and navigation states. Compared to traditional applications, web applications integrate operations with the built-in browsing capabilities of hypermedia. These novelties make web application design a complex task that requires the integration of methods and techniques developed in different "worlds". This integration is achieved in this paper by extending and customizing the Unified Modeling Language (UML) with web design concepts borrowed from the Hypermedia Design Model (HDM). Hypermedia elements are described through appropriate UML stereotypes. UML diagrams are also tailored to model operations and relate them with hypermedia elements. The approach is exemplified by describing the design of a web-based conference manager.

In this paper we discuss the use of an object-oriented approach for hypermedia applications design, including web-based, based on the Object Oriented Hypermedia Design Method (OOHDM). We first motivate our work discussing the problems encountered while designing large scale, dynamic web-based applications, which combine complex navigation patterns with sophisticated computational behavior. We argue that a method providing systematic guidance to design is needed. Next, we introduce OOHDM, describing its main activities, namely: conceptual design, navigational design, abstract interface design and implementation, and discuss how OOHDM designs can be implemented in the WWW. Finally, related work and future research in this area are further discussed. 1. A Brief Overview of OOHDM The Object-Oriented Hypermedia Design Method is a model-based approach for building large hypermedia applications. It has been used to design different kinds of applications such as: web sites and information systems,

( +) also at UNLM and COINCET. In this paper we show how to improve the architecture of Web Information Systems (WISs) using design patterns, in particular navigational patterns. We first present a framework to reason about the process of designing and implementing these applications. Then we introduce navigational patterns and show some prototypical patterns. We next show how these patterns have been used in some successful WIS. Finally we explain how patterns are integrated into the development process of WIS.

Abstract. “A pattern... describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over ” [1]. The possible benefits of using design patterns for Web applications are clear. They help fill the gap between requirements specification and conceptual modeling. They support conceptual modeling-by-reuse, i.e. design by adapting and combining already-proven solutions to new problems. They support conceptual modeling-in-the-very-large, i.e. the specification of the general features of an application, ignoring the details. This paper describes relevant issues about design patterns for the Web and illustrates an initiative of ACM SIGWEB (the ACM Special Interest Group on Hypertext, Hypermedia, and the Web). The initiative aims, with the contribution of researchers and professionals of different communities, to build an on-line repository for Web design patterns. 1

Abstract. This paper illustrates the OntoWeaver modelling approach, which relies on a set of comprehensive site ontologies to model all aspects of dataintensive web sites and thus offers high level support for the design and development of data-intensive web sites. In particular, the OntoWeaver site ontologies comprise two components: a site view ontology and a presentation ontology. The site view ontology provides meta-models to allow for the composition of sophisticated site views, which allow end users to navigate and manipulate the underlying domain databases. The presentation ontology abstracts the look and feel for site views and makes it possible for the visual appearance and layout to be specified at a high level of abstraction. 1

Integrated information systems are often realized as data-intensive Web sites, which integrate data from multiple data sources. We present a system, called Strudel, for specifying and generating data-intensive Web sites. Strudel separates the tasks of accessing and integrating a site's data sources, building its structure, and generating its HTML representation. Strudel's declarative query language, called StruQL, supports the first two tasks. Unlike ad-hoc database queries, a StruQL query is a software artifact that must be extensible and reusable. To support more modular and reusable site-definition queries, we extend StruQL with functions and describe how the new language, FunStruQL, better supports common site-engineering tasks, such as choosing a strategy for generating the site's pages dynamically and/or statically. To substantiate Strudel's benefits, we describe the re-engineering of a production Web site using FunStruQL and show that the new site is smaller, more reusable, and ...

Abstract. The term World Wide Web (WWW) emphasizes that the Web is global and many companies realize that this creates new opportunities. A considerable amount of literature on web site development stresses that, in order to attract and retain more customers, it is vital to create different versions of a web site and adapt those versions to the local communities they target. This process is usually called globalization and the different web site versions are called localized web sites. Although content management systems (CMS) for web sites provide support for multinational web sites, current web site design methodologies do not consider the issue of globalization. In general, the globalization effort is done after the web site is designed and implemented. This makes globalization much harder. In this paper, we show how to extend an existing web site design method, WSDM, to support the design of localized web sites. 1

This paper shows an environment, OOHDM-Web, that allows template driven website for applications designed using, OOHDM.. We show how this environment allows direct mapping of navigation and interface constructs of OOHDM into a library of functions in the CGI scripting environment CGI-LUA, extended with the DB-LUA package. OOHDM-Web allows implementation of hypermedia applications as CGI scripts that produce dynamically generated pages, whose contents are fed from a database and integrated with pre-defined templates. The paper presents the advantages of combining the two techniques, template-driven implementations and design methods, reaping benefits of their respective strengths.

The web is being used for applications that contain significant business logic complexity and have considerable user interface requirements. The ad hoc enhancements that have made web application software possible (such as CGI and JavaScript) have created an application support infrastructure that makes application software upgrades and maintenance very complicated. Furthermore, the web has particularly poor support for complex user interfaces. The fundamental request-reply nature of HTTP means that it is difficult to avoid artificial segmentation of an application's execution and user interface. Event-driven user interfaces are commonly used in traditional non-distributed applications. Unfortunately, the limitations of the existing web infrastructure mean that purely event-based user interaction is unsuitable within web applications. Nevertheless, we believe that integrating event-based user interaction in certain parts of a large web application will have positive effects if a suitable architecture is used. In this paper, we explore an architecture that accommodates a partial integration of an event-driven user interface and hides some of the ad hoc web infrastructure. We also suggest ways in which eventbased interaction can be incorporated within a web application framework such as J2EE.