9,059 research outputs found
Converging an Overlay Network to a Gradient Topology
In this paper, we investigate the topology convergence problem for the
gossip-based Gradient overlay network. In an overlay network where each node
has a local utility value, a Gradient overlay network is characterized by the
properties that each node has a set of neighbors with the same utility value (a
similar view) and a set of neighbors containing higher utility values (gradient
neighbor set), such that paths of increasing utilities emerge in the network
topology. The Gradient overlay network is built using gossiping and a
preference function that samples from nodes using a uniform random peer
sampling service. We analyze it using tools from matrix analysis, and we prove
both the necessary and sufficient conditions for convergence to a complete
gradient structure, as well as estimating the convergence time and providing
bounds on worst-case convergence time. Finally, we show in simulations the
potential of the Gradient overlay, by building a more efficient live-streaming
peer-to-peer (P2P) system than one built using uniform random peer sampling.Comment: Submitted to 50th IEEE Conference on Decision and Control (CDC 2011
Bibliometric Perspectives on Medical Innovation using the Medical Subject Headings (MeSH) of PubMed
Multiple perspectives on the nonlinear processes of medical innovations can
be distinguished and combined using the Medical Subject Headings (MeSH) of the
Medline database. Focusing on three main branches-"diseases," "drugs and
chemicals," and "techniques and equipment"-we use base maps and overlay
techniques to investigate the translations and interactions and thus to gain a
bibliometric perspective on the dynamics of medical innovations. To this end,
we first analyze the Medline database, the MeSH index tree, and the various
options for a static mapping from different perspectives and at different
levels of aggregation. Following a specific innovation (RNA interference) over
time, the notion of a trajectory which leaves a signature in the database is
elaborated. Can the detailed index terms describing the dynamics of research be
used to predict the diffusion dynamics of research results? Possibilities are
specified for further integration between the Medline database, on the one
hand, and the Science Citation Index and Scopus (containing citation
information), on the other.Comment: forthcoming in the Journal of the American Society for Information
Science and Technolog
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Multimedia delivery in the future internet
The term âNetworked Mediaâ 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 citizensâ 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 âon the moveâ, 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
Mobile Online Gaming via Resource Sharing
Mobile gaming presents a number of main issues which remain open. These are
concerned mainly with connectivity, computational capacities, memory and
battery constraints. In this paper, we discuss the design of a fully
distributed approach for the support of mobile Multiplayer Online Games (MOGs).
In mobile environments, several features might be exploited to enable resource
sharing among multiple devices / game consoles owned by different mobile users.
We show the advantages of trading computing / networking facilities among
mobile players. This operation mode opens a wide number of interesting sharing
scenarios, thus promoting the deployment of novel mobile online games. In
particular, once mobile nodes make their resource available for the community,
it becomes possible to distribute the software modules that compose the game
engine. This allows to distribute the workload for the game advancement
management. We claim that resource sharing is in unison with the idea of ludic
activity that is behind MOGs. Hence, such schemes can be profitably employed in
these contexts.Comment: Proceedings of 3nd ICST/CREATE-NET Workshop on DIstributed SImulation
and Online gaming (DISIO 2012). In conjunction with SIMUTools 2012.
Desenzano, Italy, March 2012. ISBN: 978-1-936968-47-
Statistical structures for internet-scale data management
Efficient query processing in traditional database management systems relies on statistics on base data. For centralized systems, there is a rich body of research results on such statistics, from simple aggregates to more elaborate synopses such as sketches and histograms. For Internet-scale distributed systems, on the other hand, statistics management still poses major challenges. With the work in this paper we aim to endow peer-to-peer data management over structured overlays with the power associated with such statistical information, with emphasis on meeting the scalability challenge. To this end, we first contribute efficient, accurate, and decentralized algorithms that can compute key aggregates such as Count, CountDistinct, Sum, and Average. We show how to construct several types of histograms, such as simple Equi-Width, Average-Shifted Equi-Width, and Equi-Depth histograms. We present a full-fledged open-source implementation of these tools for distributed statistical synopses, and report on a comprehensive experimental performance evaluation, evaluating our contributions in terms of efficiency, accuracy, and scalability
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