The success of future NGN services depends on the ability to adapt and personalize service delivery according to the user's context as well as service and device capabilities. Personalization includes not only respecting explicit user preferences, but also offering optimized multi-device communication. Flexible handling of multiple devices as well as multiple sessions is an increasing demand in the ubiquitous networking environment. In this paper, we describe how user preferences and device capability profiles for multiple devices can be managed and used for personalization. We integrated these methods into our earlier- proposed personalized communication controller (PCC), a service delivery platform component for optimizing multi-device communication through real-time decision-making. Information about related standardization efforts complements the paper.

The creation of new service revenue streams supported by consistent user experiences is one of the topics for the future service layer. Personalization over real-time decision enablement is one important option to explore for new business models. The paper introduces a novel personalization communication control mechanism across services, devices and platforms realizing realtime decision enablement for an IMS-based SDP environment, accompanied with marketing, standards and detailed technology studies.

We propose a concept for realizing access control in mobile ad-hoc networks to exclude nodes that do not contribute to the provision of network services from using them. Each node observes the behavior of its neighbors in order to build up opinions about their willingness to take part in different network activities. In turn, service is provided only to nodes that have positive opinions about them. A precondition for assigning opinions to nodes is having a means for authentication; we rely on a web-of-trust structure for this, where all nodes can issue certificates for others after they have verified their identities. A proactive certificate management system makes it possible - as the presented evaluation results show - to find optimal certificate chains between given keys and to retrieve the needed certificates quickly.

Secure communication is very important in computer networks and authentication is one of the most eminent preconditions. However, common authentication schemes are not applicable in ad hoc networks because public key infrastructures with a centralized certification authority are hard to deploy there. We propose and evaluate a security concept based on a distributed certification facility. A network is divided into clusters with one special head node each. These cluster head nodes execute administrative functions and hold shares of a network key used for certification. New nodes start to participate in the network as guests; they can only become full members with a network-signed certificate after their authenticity has been warranted by some other members. The feasibility of this concept was verified by simulation. Three different models for node mobility were used in order to include realistic scenarios as well as make the results comparable to other work. The simulation results include an evaluation of the log-on times, availability, and communication overhead.