Mahalanobis distance is a classical tool in multivariate analysis. We suggest here an extension of this concept to the case of functional data. More precisely, the proposed definition concerns those statistical problems where the sample data are real functions defined on a compact interval of the real line. The obvious difficulty for such a functional extension is the non-invertibility of the covariance operator in infinite-dimensional cases. Unlike other recent proposals, our definition is suggested and motivated in terms of the Reproducing Kernel Hilbert Space (RKHS) associated with the stochastic process that generates the data. The proposed distance is a true metric; it depends on a unique real smoothing parameter which is fully motivated in RKHS terms. Moreover, it shares some properties of its finite dimensional counterpart: it is invariant under isometries, it can be consistently estimated from the data and its sampling distribution is known under Gaussian models. An empirical study for two statistical applications, outliers detection and binary classification, is included. The results are quite competitive when compared to other recent proposals in the literature.

Transporting information from one end to the other of the network is one of the most prominent services offered by telecommunication operators, what we term the "information transport" service. Its efficient management, considering aspects like tariffs or QoS (Quality of Service), attracts much interest and research efforts. The new "frontier" is to integrate this service in the whole service delivery chain making the different stakeholders in the telecommunication business cooperate. The IMS (IP Multimedia Subsystem) service platform offers solutions embracing the current trend of respecting the Internet paradigm of transport and application layers separation, yet building interfaces between both domains. But IMS approach relegates the "information transport service" to a mere resource. This bundles IMS applicability. We propose that "information transport" regains its service status. Existing service management and composition techniques could be employed resulting on increased flexibility, new business possibilities and a better end service. We show the advantages of our approach compared to existing solutions, we discuss its complexity and analyze if it is feasible in NGN (next generation networks) and whether it is worth.

The deployment of next generation networks (NGN) is a high priority for telecommunication operators. Future access networks will be based on a multi-access architecture, in which many independent radio access technologies will collaborate to offer a unified access platform for mobile users. In this scenario, it will be fundamental to control the interactions among the different systems (i.e. networks) in the best possible way. Therefore, it is urgent to develop tools that can assist network engineers in this complex task. This paper presents xCAT (Cross-access Capacity Analysis Tool) a tool that helps in the design and planning of next generation wireless networks. We also include results from a performed analysis focused on two typical situations in future wireless composite access networks: (1) inter-technology user reallocation and (2) network collocation. The experiments assess the impact of these interactions on the overall performance of NGN systems.

The design of an extended and generic authentication, authorization, accounting, and charging architecture (AAAC Arch.) has been performed within the IST project MobyDick. In addition, this architecture has been implemented to address MobyDick's main objective: to facilitate the deployment of a ubiquitous mobile IPv6-based, quality-of-service (QoS)-aware infrastructure through a flexible and evolutionary AAAC Architecture. While the AAAC Arch. is based on the DIAMETER protocol, basic concepts developed cover session and services models, user profiles to allow for user mobility and QoS-aware authorization. Based on those basic building blocks for the extended AAAC Arch., the implementation of user registration, service authorization, metering, accounting, charging, and auditing is discussed. The paper closes with the presentation of the two trial sites used and their testbeds.