Architecture for Cooperative Prefetching in P2P Video-on- Demand System

Most P2P VoD schemes focused on service architectures and overlays optimization without considering segments rarity and the performance of prefetching strategies. As a result, they cannot better support VCRoriented service in heterogeneous environment having clients using free VCR controls. Despite the remarkable popularity in VoD systems, there exist no prior work that studies the performance gap between different prefetching strategies. In this paper, we analyze and understand the performance of different prefetching strategies. Our analytical characterization brings us not only a better understanding of several fundamental tradeoffs in prefetching strategies, but also important insights on the design of P2P VoD system. On the basis of this analysis, we finally proposed a cooperative prefetching strategy called "cooching". In this strategy, the requested segments in VCR interactivities are prefetched into session beforehand using the information collected through gossips. We evaluate our strategy through extensive simulations. The results indicate that the proposed strategy outperforms the existing prefetching mechanisms.Comment: 13 Pages, IJCN

Multimedia delivery in the future internet

The term “Networked Media” implies that all kinds of media including text, image, 3D graphics, audio and video are produced, distributed, shared, managed and consumed on-line through various networks, like the Internet, Fiber, WiFi, WiMAX, GPRS, 3G and so on, in a convergent manner [1]. This white paper is the contribution of the Media Delivery Platform (MDP) cluster and aims to cover the Networked challenges of the Networked Media in the transition to the Future of the Internet. Internet has evolved and changed the way we work and live. End users of the Internet have been confronted with a bewildering range of media, services and applications and of technological innovations concerning media formats, wireless networks, terminal types and capabilities. And there is little evidence that the pace of this innovation is slowing. Today, over one billion of users access the Internet on regular basis, more than 100 million users have downloaded at least one (multi)media file and over 47 millions of them do so regularly, searching in more than 160 Exabytes1 of content. In the near future these numbers are expected to exponentially rise. It is expected that the Internet content will be increased by at least a factor of 6, rising to more than 990 Exabytes before 2012, fuelled mainly by the users themselves. Moreover, it is envisaged that in a near- to mid-term future, the Internet will provide the means to share and distribute (new) multimedia content and services with superior quality and striking flexibility, in a trusted and personalized way, improving citizens’ quality of life, working conditions, edutainment and safety. In this evolving environment, new transport protocols, new multimedia encoding schemes, cross-layer inthe network adaptation, machine-to-machine communication (including RFIDs), rich 3D content as well as community networks and the use of peer-to-peer (P2P) overlays are expected to generate new models of interaction and cooperation, and be able to support enhanced perceived quality-of-experience (PQoE) and innovative applications “on the move”, like virtual collaboration environments, personalised services/ media, virtual sport groups, on-line gaming, edutainment. In this context, the interaction with content combined with interactive/multimedia search capabilities across distributed repositories, opportunistic P2P networks and the dynamic adaptation to the characteristics of diverse mobile terminals are expected to contribute towards such a vision. Based on work that has taken place in a number of EC co-funded projects, in Framework Program 6 (FP6) and Framework Program 7 (FP7), a group of experts and technology visionaries have voluntarily contributed in this white paper aiming to describe the status, the state-of-the art, the challenges and the way ahead in the area of Content Aware media delivery platforms

The Semantic Grid: A future e-Science infrastructure

e-Science offers a promising vision of how computer and communication technology can support and enhance the scientific process. It does this by enabling scientists to generate, analyse, share and discuss their insights, experiments and results in an effective manner. The underlying computer infrastructure that provides these facilities is commonly referred to as the Grid. At this time, there are a number of grid applications being developed and there is a whole raft of computer technologies that provide fragments of the necessary functionality. However there is currently a major gap between these endeavours and the vision of e-Science in which there is a high degree of easy-to-use and seamless automation and in which there are flexible collaborations and computations on a global scale. To bridge this practice–aspiration divide, this paper presents a research agenda whose aim is to move from the current state of the art in e-Science infrastructure, to the future infrastructure that is needed to support the full richness of the e-Science vision. Here the future e-Science research infrastructure is termed the Semantic Grid (Semantic Grid to Grid is meant to connote a similar relationship to the one that exists between the Semantic Web and the Web). In particular, we present a conceptual architecture for the Semantic Grid. This architecture adopts a service-oriented perspective in which distinct stakeholders in the scientific process, represented as software agents, provide services to one another, under various service level agreements, in various forms of marketplace. We then focus predominantly on the issues concerned with the way that knowledge is acquired and used in such environments since we believe this is the key differentiator between current grid endeavours and those envisioned for the Semantic Grid

Rethinking tourism destinations: collaborative network models for the tourist 2.0

In the increasingly saturated tourism market, an effective tourism destination management is essential to support competitive and sustainable growth. The topic becomes interesting in light of the spread of the collaborative network (CN) organisational models and the massive diffusion of web 2.0 and mobile technology. The formers have proven to give concrete opportunities of development in many industrial sectors, the latter has been changing the way tourists experience a destination. Even if several case studies of CNs in tourism are known, a comprehensive study of how tourism destinations can benefit of CN models and enabling technologies is not present; especially in the effort to help tourism destinations in setting up services able to actively support each phase of the tourist 2.0 lifecycle. In this paper we highlight how CN models are able to support the tourism destination management in order to gain competitiveness for local areas, to improve flexibility in services provision and to give tourists the possibility to live an augmented tourism experience. Furthermore, a review of the most suitable forms of collaborative network for tourism destination and their ways to actively support the augmented experience of the tourist 2.0 are proposed

Strategic teaching in a virtual context : a study on tutor training in continuing education

Adult students who start a distance-studying program need to develop a strategic learning that allows them to adapt themselves to the demands of distance education and achieve their learning goals successfully. The tutor becomes a fundamental factor when it comes to facilitating these students' adaptation process to distance studying as well as the development of their strategic learning. In this article it is presented a qualitative study on the training process of a group of tutors in strategic distance teaching and learning; it is also presented the analysis of the changes generated in them regarding conceptual and strategic knowledge, both in an academic (as students in the course) and a professional (as tutors) level. Results point out that those tutors who managed to develop higher levels as strategic learners during the training course, accordingly developed a bigger conceptual knowledge and a better performance as strategic tutors

Strategic Teaching in a Virtual Context: A Study on Tutor Training in Continuing Education

Adult students who start a distance-studying program need to develop a strategic learning that allows them to adapt themselves to the demands of distance education and achieve their learning goals successfully. The tutor becomes a fundamental factor when it comes to facilitating these students’ adaptation process to distance studying as well as the development of their strategic learning. In this article it is presented a qualitative study on the training process of a group of tutors in strategic distance teaching and learning; it is also presented the analysis of the changes generated in them regarding conceptual and strategic knowledge, both in an academic (as students in the course) and a professional (as tutors) level. Results point out that those tutors who managed to develop higher levels as strategic learners during the training course, accordingly developed a bigger conceptual knowledge and a better performance as strategic tutors.Adult students who start a distance-studying program need to develop a strategic learning that allows them to adapt themselves to the demands of distance education and achieve their learning goals successfully. The tutor becomes a fundamental factor when it comes to facilitating these students’ adaptation process to distance studying as well as the development of their strategic learning. In this article it is presented a qualitative study on the training process of a group of tutors in strategic distance teaching and learning; it is also presented the analysis of the changes generated in them regarding conceptual and strategic knowledge, both in an academic (as students in the course) and a professional (as tutors) level. Results point out that those tutors who managed to develop higher levels as strategic learners during the training course, accordingly developed a bigger conceptual knowledge and a better performance as strategic tutors