Vol.6 No.1 March 1, 2007
Editorial (pp001-001)
        B. White   

Research articles: 
Selecting Services for Web Applications: The Open Hypermedia Case (pp002-018)
        N. Karousos, M. Tzagarakis, and A. Tsakalidis
As long as the volume of the distributed information in the Internet increases, the need for useful and easy-to-use 3^rd party services in Web Applications will be growing. Web developers adopt tactics for integrating external services into their applications, aiming to enrich both utility and efficiency with low cost. A variety of services derived from the area of Open Hypermedia Systems (OHS) can augment web functionality with valuable hypermedia features. Towards that, this paper proposes a framework for enabling the provision of hypermedia services to web developers in a service-oriented manner. It investigates and analyzes the requirements of developers for easily inserting hypermedia functionality into Web applications, thus facilitating rapid prototyping of web applications. A Service Discovery Mechanism for finding and using hypermedia services is defined, and solutions for increasing the usage of hypermedia systems by web developers are proposed.

Engineering Web Applications Using Roles  (pp019-048)
        G. Rossi, J. Nanard, M. Nanard, and N. Koch
Although role modeling is a topic that has been treated over years in the object-oriented community, its use in the life cycle of Web Engineering, and particularly in object-oriented Web design methods, has been seldom discussed and used yet. In this paper, we introduce roles in the modeling and design armory of existing Web engineering methods and show how it improves their expressiveexpres power and help to solve design problems that appear frequently in Web applications. We first survey the state of the art of Web engineering modeling approaches. A simple example is used to point out some situations in classic Web engineering modeling where it is not possible to express that objects or nodes should change their properties (attributes or behaviors) according to the collaborating subject (the objects which send them messages or the nodes which are linked to them). Next, we introduce the object-oriented role concept and discuss how it has been used so far in the software engineering community and how it can be useful for Web engineering modeling. Existing methods (like UWE and OOHDM) are used as an example to show how to introduce roles during the Web engineering process. We compare our approach with others and conclude with some further research we are pursuing.

Crawling the Infinite Web (pp049-072)
        R. Baeza-Yates and C. Castillo
Many publicly available Web pages are generated dynamically upon request, and contain links to other dynamically generated pages. Web sites that are built with dynamic pages can create, in principle, a very large amount of Web pages. This poses a problem for the crawlers of Web search engines, as the network and storage resources required for indexing Web pages are neither infinite nor free. In this article, several probabilistic models for user browsing in infinite Web sites are proposed and studied. These models aim at predicting how deep users go while exploring Web sites. We use these models to estimate how deep a crawler must go to download a significant portion of the Web site content that is actually visited. The proposed models are validated against real data on page views in several Web sites, showing that, in both theory and practice, a crawler needs to download just a few levels, no more than 3 to 5 clicks away from the start page, to reach 90% of the pages that users actually visit.

Industrial Acceptability of Web Design Methods: an Empirical Study (pp073-096)
        F. Garzotto and V. Perrone
In this work we present the results of a study that has aimed at identifying the requirements for Web design methods that may influence the industrial acceptability, that is, the characteristics that prevent, or contribute to, the adoption of design methods in a business environment. The empirical study involved (by way of focus groups and surveys), over 100 potential users of Web design methods including project managers, analysts, information architects, visual designers, implementers, recruited from companies and non academic institutions intensively involved in the development of Web based applications. Our study has gathered qualitative and quantitative information that highlight expectations and needs of stakeholders of Web design methods. It has highlighted that usability, modularity, scalability, customizability, support to fast prototyping and incremental development, support to design-related activities (training, project management, design documentation delivery) are critical requirements for a design method to be adopted in the industrial practice. To define our study, we have adopted a holistic perspective. We have investigated requirements looking at design methods as to engineering products that should work within the overall development process in which design occurs, and within the organizational context in which this process takes place.

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