Engineering device-independent web services

Abstract

The popularity of computing devices such as Personal Digital Assistants (PDAs) and mobile phones have been increasingly and these devices have been getting more powerful every day. Although the latest PDAs are even able to display frames, it is still important to adapt the content for these devices in order to provide a satisfactory surfing experience for users. Web services in the near future will not only have to support mobile access, but will also have to deal with other forms of Web access such as voice interfaces. Hence, Web services will often need to be {\em device-independent} and will have to support different XML Web formats. Although much work has been done on providing mobile access to Web content, the focus has mainly been the adaptation of HTML content to make it viewable on mobile devices that might have memory and screen-size limitations. Only a few attempts have been made to date to integrate device-independence into the design, implementation and maintenance phases of Web services. This dissertation provides solutions to the problem of designing and implementing interactive, maintainable, device-independent Web services. It introduces a novel XML/XSL-based design and implementation technique and a development tool suite to support the Web developer. The constructed services can be accessed by a wide range of Web devices such as mobile phones, PDAs with micro HTML browsers, speech-based Web interfaces and traditional full-fledged HTML browsers. My general thesis is that Web services can effectively be made device-independent if device-independence support is integrated into the Web service design, implementation and maintenance phases. I present an extended model of the traditional Web service life cycle that takes device-independence support into account and describe the Device-Independent Web Engineering (DIWE) framework for engineering device-independent Web services. I introduce the novel concepts of page splitting, process partitioning and XSL stylesheet pre-processing.

Mobile Geräte wie Personal Digital Assistants (PDAs) und Mobiltelefone sind in den letzten Jahren sehr populär und leistungsfähig geworden. Die neuesten PDAs köonnen sogar mit Frames in Webseiten darstellen. Trotzdem ist es noch immer wichtig, den Webinhalt für diese Geräte so anzupassen, dass die Benutzer zufrieden sind und eine positive Erfahrung mit der Website haben. Bald werden viele Websites nicht nur mobilen Zugang, sondern andere Formen des Webzugangs wie zum Beispiel Sprachschnittstellen unterstützen. Die Websites der Zukunft müssen geräteunabhängig (device-independent) sein. Der Fokus der Forschung bis jetzt war die Anpassung und Abbildung des HTML Inhalts von Websites damit sie auf mobilen Geräten mit wenig Hauptspeicher und kleinen Displays dargestellt werden können. Nur wenige haben versucht, Geräateunabhängigkeit in den Design-, Implementierungs-, und Wartungsphasen der Website zu integrieren. Diese Dissertation presentiert L\"osungen zum Problem des Entwerfens und der Implementierung von interaktiven, ger\"ateunabh\"angigen Webservices. Sie beschreibt eine neue XML/XSL-basierte Methodologie und ein Webentwicklungswerkzeug.