Vol.7 No.4 December 1, 2008       
 Web Usability and Accessibility

Editorial (pp257-257)
        S. Abrahão, C. Cachero, and M. Matera

Research Articles:
Web Application Evaluation and Refactoring: A Quality-Oriented Improvement Approach (pp258-280)
        L. Olsina, A. Garrido, G. Rossi, D. Distante, and G. Canfora
Web applications must be usable and accessible; at the same time, their continuous evolution makes it difficult to keep a high degree of external quality. Refactoring is a practice of agile methods well-suited for the maintenance and evolution of Web applications. However, this practice is mainly intended and used to improve maintainability and extensibility of the design and code rather than external qualities such as usability. We believe that the concept of refactoring as “behavior-preserving transformations” can be applied to the navigation and presentation models of a Web application with the purpose of improving external quality. For this reason we have defined the concept of Web model refactoring. This paper demonstrates how it is possible to improve the external quality of a Web application by combining a mature quality measurement and evaluation method (WebQEM) with Web model refactoring. WebQEM is used to identify needs for improvement, recommend Web model refactorings and assess their impact on some defined attributes of a Web product entity. We present a case study showing how a typical shopping cart in an e-commerce site can improve its usability and content quality with our integrated improvement approach.

An investigation of tool support for accessibility assessment throughout the development process of Web sites (pp281-298)
        J. Xiong and M. Winckler
This paper investigates the support given by currently available tools for dealing with accessibility at different phases of the development process. At first, we provide a detailed classification of accessibility guidelines according to several levels of automation. Then we analyze which automated inspection techniques are supported by currently available tools for building Web sites. By means of a case study we try to assess the possibility of fixing accessibility problems at early phases of the development process. Our results provide insights for improving current available tools for Web design in order to take accessibility into account at all phases of development process of Web sites.

Quality and Potential for Adoption of Usability Evaluation Methods (pp299-317)
        D. Bolchini, and F. Garzotto
Web usability evaluation methods are conceptual tools which should enable web designers, web engineers and usability engineers to detect and possibly anticipate usability problems of a web application, and eventually to provide requirements for improving the quality of the user experience. As the number of techniques and methods available grows, practitioners need clear criteria to choose which methods best fit their project needs, resources and organizational goals. Therefore, it becomes more and more important to foster research towards evaluating the quality of the usability evaluation methods, especially in view of their potential adoption among practitioners. Besides focussing on known attributes of intrinsic quality of the method (such as coverage, reliability and validity), this paper also explores “perceived” quality attributes related to the potential adoption of the method among practitioners, namely in terms of learnability, perceived difficulty, and cost-effectiveness. We report two empirical studies which have been carried out to measure these quality attributes on a state-of-the-art inspection method for web usability, called MiLE+. The result of this work can be useful to scholars because it provides validation examples and a set of quality attributes to apply to other usability evaluation methods; it also benefits practitioners because it offers a clear guidance about what requirements they should look for when selecting a usability evaluation method for their own project needs.

An Intelligent Visual Dictionary for Italian Sign Language (pp318-338)
        T. Di Mascio and R. Gennari
Sign languages are visual-gestural languages developed mainly in deaf communities; their tempo-spatial nature makes it difficult to write them, yet several transcription systems are available for them. Most sign language dictionaries interact with users via a transcription-based interface; thus users need to be expert of that specific transcription system. The e-LIS dictionary is the first web bidirectional dictionary for Italian sign language-Italian; using the current e-LIS interface, users can define a sign interacting with intuitive iconic images, ignoring the underlying transcription system. Nevertheless this interface assumes that its users are expert signers, knowledgeable about the formational rules of signs. The e-LIS ontology, which specifies how to form a sign, allows even non-expert signers to use the dictionary from Italian sign language to Italian. This is realised through a novel visual interface for transparently browsing and querying the e-LIS ontology and the underlying database. The interface prototype was designed following the user centred design methodology. As such, our work constitutes the first attempt at making the e-LIS dictionary an intelligent visual dictionary, usable by learners of Italian sign language who are not expert signers yet. This paper reports on the design of the first prototype of the ontology-based visual interface, and outlines its evaluation plan.

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