Jul 1st, 2010 by nlescoua
Mary-Luc Champel†, Kévin Huguenin‡, Anne-Marie Kermarrec⁰ and Nicolas Le Scouarnec† have received the best paper award at ICDCS’10 for their work on network coding.
Network coding is a communication paradigm that can be applied to numerous fields since it can enhance wireless networking, content distribution, distributed storage… However, the main pitfall that prevents the use of network coding today is its high decoding cost. The awarded paper describes LT Network Codes, a new kind of network coding that offers a low complexity decoding procedure. LT Network Codes significantly broaden the application spectrum for network codes : computationally limited devices may now run applications relying on network coding while they could not afford the decoding cost with previously existing randomized network codes.
Mary-Luc Champel, Kévin Huguenin, Anne-Marie Kermarrec, and Nicolas Le Scouarnec. LT Network Codes. In 30th International Conference on Distributed Computing Systems (ICDCS), Jun. 21, 2010, Genoa, Italy
† Technicolor
‡ IRISA / Université Rennes 1
⁰ INRIA Rennes Bretagne Atlantique
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Feb 12th, 2010 by aboutet
We organize SNDS 2010, the 1st Workshop on Social Networks and Distributed Systems which will be hold in conjuction with PODC 2010, July 29, 2010, Zurich, Switzerland.
Tags: Peer to Peer, Social Network
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Apr 11th, 2010 by akermarrec
Anne-Marie Kermarrec and Michel Raynal gave a talk in the context of Gerard Berry’s course at the Collège de France in Januray 2010. The talks are available in French.
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Jun 11th, 2010 by cbouton
Title : Recursion in distributed computing by Eli Gafni, UCLA
Abstract :
The benefits of developing algorithms via recursion are well known.
However, little use of recursion has been done in distributed algorithms, in spite of the fact that recursive structuring principles for distributed systems have been advocate since the beginning of the field. We present several distributed algorithms in a recursive form,
which makes them easier to understand and analyze. Also, we expose several interesting issues arising in recursive distributed algorithms. Our goal is to promote the use and study of recursion in distributed algorithms. (Joint Work with Sergio Rajsbaum, UNAM.)
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Apr 23rd, 2010 by akermarrec
Yann Gripay, LIRIS Lyon,
Monday April 26th, 10:00a.m. Salle Aurigny (D165)
A Data-oriented Declarative Approach for Pervasive Environments
Pervasive environments pose new challenges in order to exploit their full potential, in particular through the management of complex interactions between distributed resources. Their heterogeneous data sources and functionalities are not homogeneously manageable in today’s systems. This is a big issue when building pervasive applications: imperative programming languages (e.g., C++, Java), classical query languages for databases (e.g., SQL), and network protocols (e.g., JMX, UPnP) must be combined in ad hoc developments, which is neither convenient nor suitable as a long-term solution.
Declarative approaches offer the advantage of providing a logical view on resources that abstracts physical access issues and enables optimization techniques. SQL queries over relational databases are a typical and well-known illustration of those approaches. Therefore, querying data sources and functionalities in a declarative way is recognized as a major issue in pervasive environments in order to simplify the development of applications. Despite a lot of propositions, a clear understanding of the interplays between relational data, data streams and services is still lacking and is the major bottleneck toward the declarative definition of pervasive applications, instead of the current ad hoc development of such applications.
In our work, we propose a data model for pervasive environments, namely the SoCQ data model (standing for Service-oriented Continuous Query).We define a data-oriented view of those environments: the standard notion of database is extended to come up with a broader notion, defined as relational pervasive environment, integrating in the same model relational data, data streams and distributed services. We also define an algebra, namely the Serena algebra, that enables the declarative expression of one-shot or continuous queries homogeneously combining those data sources. We moreover propose a SQL-like language based on this algebra. A prototype of Pervasive Environment Management System (PEMS) that supports our data model has been implemented using the OSGi framework, and experimentations have been conducted to validate our approach.
The perspectives of this work focus on query optimization issues in this new context and on the integration of this approach within P2P environments. Applications are envisioned in the domain of intelligent buildings (exploiting P2P sensor networks) and in the domain of social networks (information sharing at large scale).
Tags: Sensor Network
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Apr 22nd, 2010 by cbouton
Soft-security to self-preserve autonomic systems: on the application of reputation management schemes
In this talk, we first analyze the principles for an autonomic system to discuss new security requirements and issues that target malicious and selfish nodes. We then dissect a reputation management scheme to study the cost vs. the benefit of its application in P2P systems. Borrowing techniques from game theory, we present a framework based on the Iterated Prisoner’s Dilemma to justify the adoption of reputation management schemes in self-organizing networks. We model the interactions of rational and selfish nodes in distributed systems and we study how a node takes into account the change of its reputation when deciding its behavior in a transaction. Finally, we discuss the Nash equilibrium in the system.
Once we have analyzed the importance of reputation management schemes, we estimate their performance for specific applications. We first simulate the capability of these schemes in reducing corrupted file transfers in end-user collaborative content distribution systems. Then, we define a token-based mechanism to improve the application of reputation management schemes in mobile scenarios, i.e., to reduce the problem of reputation bootstrap in new communities and accelerate the identification of malicious nodes.
Tags: Reputation
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Apr 20th, 2010 by akermarrec
Eric Ruppert, York University
(joint work with Rachid Guerraoui)
Thursday April 22nd, 2:30p.m. Salle Sicile (F302)
Names Trump Malice: Tiny Mobile Agents Can Tolerate Byzantine Failures
This talk will briefly describe the population protocol model of ad hoc mobile computing in which agents have severely restricted memory, highly unpredictable movement and no initial knowledge of the system. Then, it will describe how the model changes when agents are given unique identitifiers. In the new model, each agent’s memory can store O(1) bits, the unique identifier, and O(1) other agents’ identifiers. Inputs are distributed across n agents, and all agents must converge to the correct output value. We give a universal construction that proves the model is surprisingly strong: It can solve any decision problem in NSPACE(n log n). Moreover, the construction is robust with respect to Byzantine failures of a constant number of agents.
Tags: Population Protocol
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