DISC 2008
September 22-24, 2008, Arcachon, France.
22nd International Symposium on Distributed Computing

Invited Speakers

The invited speakers list (in alphabetic order):

  • Phillip B. Gibbons,

    Fun with Networks: Social, Sensor, and Shape Shifting

    Part of the "fun" in algorithmic research in networking arises from the emergence of important new network settings. These new settings bring new algorithmic problems to be formulated and studied. In this talk, we consider three such settings. First, we consider social networks and how they can be used in a novel way to defend against Sybil attacks in P2P distributed systems. In a Sybil attack, a malicious user creates a very large number of fake identities in order to out-vote the honest users in collaborative P2P tasks. Our protocols, SybilGuard and its follow-on SybilLimit, use randomized routes (a variant of random walks) on a social network topology in order to reject all but a limited number of votes by fake identities. Second, we consider wireless sensor networks and how to perform robust, in-network aggregation in an energy-efficient way. Our approach, Synopsis Diffusion, seeks to combine the energy-efficiency of tree-based aggregation with the robustness of gossip-based aggregation. This is accomplished through the use of order-and-duplicate-insensitive (ODI) synopses, which enable the efficient, robust use of the broadcast wireless medium. We present a theory of ODI synopses, as well as open problems. Finally, we look ahead to a new network setting arising from modular robotic ensembles of billions of submillimeter-sized modules, called catoms. Catoms dynamically form physical shapes by "rolling" across each other under software control. While we present a few initial results, devising an effective communication scheme for such networks remains an open problem.
    This talk covers joint work with Casey Helfrich, Michael Kaminsky, Amit Manjhi, Todd Mowry, Suman Nath, Padmanabhan Pillai, Srinivasan Seshan, and Haifeng Yu.

  • David Harel,

    In Silico Biology, or On Comprehensive and Realistic Modeling

    The talk shows the way software and systems engineering, especially of reactive systems, can be applied beneficially to the life sciences. We will discuss the idea of comprehensive and realistic computerized modeling of biological systems. In comprehensive modeling the main purpose is to understand an entire system in detail, utilizing in the modeling effort all that is known about the system, and to use that understanding to analyze and predict behavior in silico. In realistic modeling the main issue is to model the behavior of actual elements, making possible totally interactive and modifiable realistic executions and simulations that reveal emergent properties. I will address the motivation for such modeling and the philosophy underlying the techniques for carrying it out, as well as the crucial question of when such models are to be deemed valid, or complete. The examples I will present will be from among the biological modeling efforts my group has been involved in: T cell development in the thymus, lymph node behavior, organogenesis of the pancreas, fate determination in the reproductive system of C. elegans , and a generic cell model. I will also discuss a long-term "grand challenge" --- to model a full multi-cellular organism.

  • Alexander A. Shvartsman,

    Distributed Cooperation and Adversity: Complexity Trade-Offs

    The problem of cooperatively performing a collection of tasks in a decentralized setting where the computing medium is subject to undesirable perturbations is one of the fundamental problems in distributed computing, with applications encompassing such important areas as Internet supercomputing, parallel simulation, and multi-agent collaboration. The perturbations in the computing medium are typically due to processor and software failures (benign or malicious), communication breakdowns, and unpredictable delays. Such perturbations become even more prominent when an application needs to harness massive amounts of available computational resources. To develop efficient solutions for computation problems based on distributed cooperation, it is important to understand efficiency trade-offs characterizing the ability of p processors to cooperate on t tasks in key models of computation in the presence of adversity. In this talk we survey historical and recent results for distributed cooperation roughly grouped along the following topics: (i) fundamental failure-sensitive bounds for distributed cooperation problems for synchronous crash-prone processors, (ii) upper and lower bounds on distributed cooperation in shared-memory models, (iii) bounds on distributed work in message-passing models and on redundant work for processors that may experience prolonged absence of communication.


Pôle RésCom