Catálogo de publicaciones - libros

The VidShare project develops a management platform for Peer-to-Peer multimedia asset distribution across heterogeneous access networks, fixed and mobile, with Intellectual Property Management and Protection (IPMP). A key objective is to build an architecture that is interoperable with different content management and IPMP solutions. The project utilises MPEG REL as a rights exp-ression language and works with the evolving MPEG-21 Multimedia Framework. The platform supports a number of business models including rights based personal multimedia sharing, distributed multimedia management for corpora-tions, and the retailing of video content including the super distribution of content.

Through the past years, several digital rights management (DRM) solutions for controlled dissemination of digital information have been developed using cryptography and other technologies. Within so many different solutions, however, interoperability problems arise, which increase the interest on integrated design and management of these technologies. Pursuing these goals, this paper presents a framework which aims at promoting interoperability among DRM systems, using a service-oriented architecture (SOA) and a high-level policy modeling approach.

Pervasive environments will witness heterogeneous smart embedded devices (e.g. sensors, actuators) integrated into user’s living environment (e.g. smart homes and hospitals) and provide a multitude of information that can transparently support user’s lifestyle. One promising application resulting from the management and exploitation of this information is the human activity recognition. In this paper we briefly describe our activity recognition architecture and focus on an important management component of this architecture using the concept of object networks. We explore how object networks can integrate various sensor networks and heterogeneous devices into a coherent network through embedded context and role profile and at the same time support distributed context reasoning. The paper also describes the mechanisms used to eliminate and refine context information that is deemed irrelevant due to user behaviour changes over time, by employing the idea of role fitness.

This work presents an Inter-Domain Bandwidth Broker (BB) based Service Level Agreements (SLAs) Negotiation Model for Differentiated Services (DiffServ) networks. A BB in each DiffServ domain handles SLAs on behalf of its domain by communicating with its neighboring peers. The proposed model uses a destination-based SLAs aggregation to increase signaling and state scalability, and it uses a BB-based inter-domain routing to increase resource utilization. The experimental results are provided to verify the achievements.

Loss Differentiation Algorithms (LDA) are currently used to deter-mine the cause of packet losses with an aim of improving TCP performance over wireless networks. In this work, we are interested in the distinction between losses due to interferences on 802.11 links from those due to congestions. To this end, we compare different LDA schemes existing in the literature and a proposal of a cross-layer LDA which use MAC parameters. The efficiency of our solution is then demonstrated through simulations.

Mobility management has become an important issue in 4G networks due to the integration of multiple network access technologies. Traditionally, only the received signal strength has been considered for the vertical handover. However, more considerations will be necessary to satisfy the end user’s preferences. In this paper, we propose an Autonomic Handover Manager (AHM) based on the autonomic computing concept to decide the best network interface to handover in 4G networks. AHM decides the appropriate policy for the specific service or application without the user’s intervention using the context information from the mobile terminal, the network and the user. We present the context information and the context evaluation function to decide handover based on the user preferences. We then describe the scenario to validate its feasibility using multimedia conferencing service on the mobile terminal.

In the case of next generation wireless networks, different users with various multi-homed personal wireless devices will aim to exploit the full potential of the choice of services and applications available over different radio access networks. In their selection of a certain radio access network consumers will consider money and delay preferences for the current application and will rely on intelligent network-selection decision strategies to aid them in their choice. This paper describes the evaluation of an intelligent utility-based strategy for network selection in a multi-access network situation for transfer of large non real-time data files. A number of scenarios are examined which compare the proposed network selection strategy against other possible strategies. Test results show how by using this network selection strategy significant benefits in terms of combined average delay and cost per file transferred as well as transfer efficiency are obtained.

After years of research on ad hoc networks, practical wireless mesh networks are moving towards mainstream industry deployment. As wireless mesh networks become more ubiquitous, how to enable distributed applications and services is a challenging research topic. A new network architecture called OverMesh is recently proposed, in which computational overlays provide the facility to deploy distributed services across mobile mesh nodes. In this paper, we present the first implementation of the OverMesh architecture. The overlays are built over an IEEE 802.11s wireless mesh network pre-standard prototype. The platform enables development and deployment of concurrent distributed experiments on wireless mesh networks. Based on this platform, we further introduce a cross-layer searching algorithm, which combines traditional overlay searching with ad hoc network routing so that a physically short searching route is facilitated. Both experimentation and simulation results are presented.

The TISPAN workgroup inside ETSI is currently working on accommodating the IMS (IP Multimedia Subsystem) architecture, which has been created for the mobile world, to the fixed scenario where there is a new important element to be taken into account: the Residential Gateway (RGW). This element is typically considered as a customer device where providers do not usually have anything to configure. However, in order to achieve real end-to-end Quality of Service (QoS) this cannot be true anymore.

This paper focuses on the way that a RGW is capable of configuring itself (an interface with the providers is also available), regarding Quality of Service parameters, into a Next Generation Network (NGN) scenario. The proposed RGW architecture is also flexible enough so as to adapt the QoS management mechanism to different possible scenarios, e.g. configured by the provider, by the customer or even autoconfigured by the RGW itself. A specific scenario, where a RGW is deployed in the TISPAN NGN architecture, will be explained and validated to proof the concept of the RGW architecture.

The support of real-time traffic in class-based IP networks requires reservation of resources, accompanied by admission control in order to guarantee that newly admitted real-time traffic flows do not cause any violation to the Quality of Service (QoS) perceived by the already established ones. In this paper we highlight certain issues with respect to bandwidth allocation and admission control for supporting real-time traffic in class-based IP networks. We investigate the implications of topological placement of both bandwidth allocation and admission control schemes. We show that their performance depends highly on the location of the employed procedures with respect to the end-users and the various network boundaries. We conclude that the strategies for applying these schemes should be location-aware, because their performance at different points in a class-based IP network can be different and can deviate from the expected performance. Through simulations we also provide a quantitative view of these deviations.