A QoS content adaptation framework for nomadic users

The tremendous growth of the Internet has introduced a number of interoperability problems for distributed multimedia applications. These problems are related to the heterogeneity of client devices, network connectivity, content formats, and user's preferences. The diversity of client devices posed some challenges in aligning and customizing the exchanged data between different users using different devices and with different preferences. Another trend in the telecommunication world that is starting to surface is ubiquitous computing environment where there is a shift of computing technology from the desktop to the background. One of its most notable attributes is its potential to extend the scope of the user's reachability. The purpose of this thesis is to present a framework for multimedia content adaptation that addresses diversity, heterogeneity, and ubiquity. The framework takes into consideration the profile of communicating users, devices, network connectivity, exchanged content format, context description, and available adaptation services to find a chain of adaptation services that could be applied to the content. Major part of the framework is a QoS-based selection algorithm that finds the best sequence of adaptation services and their QoS configuration that can maximize the user's satisfaction with the delivered content. A restricted version of the framework is used to find the best combination for the number of media streams and their corresponding configuration for presentational multimedia applications. The framework also forms the core of an architecture for supporting personal mobility. In an environment where a user has access to many communication devices, it is more convenient that the system makes the choice between all these devices depending on previously defined user preferences. The system will also select the values for the QoS parameters that give the user the best satisfaction with the session. We will also describe an extension of the architecture to support service and personal mobility in an ubiquitous computing environment. Protecting the user's privacy is also addressed in this thesis, with a focus on protecting the confidentiality of the user's preferences during session negotiation