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Erik Aurell

  1. Network inference using asynchronously updated kinetic Ising Model.

    Втр, 11/30/2010 - 16:01 — SomNambul
    Authors: Erik Aurell, Hong-Li Zeng, Mikko Alava, Hamed Mahmoudi
    Subjects: Computation
    Abstract

    Network structures are reconstructed from dynamical data by respectively
    naive mean field (nMF) and Thouless-Anderson-Palmer (TAP) approximations. For
    TAP approximation, we use two methods to reconstruct the network: a) iteration
    method; b) casting the inference formula to a set of cubic equations and
    solving it directly. We investigate inference of the asymmetric Sherrington-
    Kirkpatrick (S-K) model using asynchronous update. The solutions of the sets
    cubic equation depend of temperature T in the S-K model, and a critical
    temperature Tc is found around 2.1.

  2. The Accuracy of Tree-based Counting in Dynamic Networks.

    Втр, 04/27/2010 - 15:02 — SomNambul
    Authors: Erik Aurell, Supriya Krishnamurthy, John Ardelius, Mads Dam, Rolf Stadler, Fetahi Wuhib
    Subjects: and Cluster Computing, Distributed, Parallel
    Abstract

    Tree-based protocols are ubiquitous in distributed systems. They are
    flexible, they perform generally well, and, in static conditions, their
    analysis is mostly simple. Under churn, however, node joins and failures can
    have complex global effects on the tree overlays, making analysis surprisingly
    subtle. To our knowledge, few prior analytic results for performance estimation
    of tree based protocols under churn are currently known. We study a simple
    Bellman-Ford-like protocol which performs network size estimation over a
    tree-shaped overlay.

  3. Bounds on Thresholds Related to Maximum Satisfiability of Regular Random Formulas.

    Чт, 04/15/2010 - 15:01 — SomNambul
    Authors: Vishwambhar Rathi, Erik Aurell, Lars Rasmussen, Mikael Skoglund
    Subjects: Information Theory
    Abstract

    We consider the regular balanced model of formula generation in conjunctive
    normal form (CNF) introduced by Boufkhad, Dubois, Interian, and Selman. We say
    that a formula is $p$-satisfying if there is a truth assignment satisfying
    $1-2^{-k}+p 2^{-k}$ fraction of clauses. Using the first moment method we
    determine upper bound on the threshold clause density such that there are no
    $p$-satisfying assignments with high probability above this upper bound. There
    are two aspects in deriving the lower bound using the second moment method.

  4. Bounds on Threshold of Regular Random $k$-SAT.

    Пнд, 02/08/2010 - 16:01 — SomNambul
    Authors: Vishwambhar Rathi, Erik Aurell, Lars Rasmussen, Mikael Skoglund
    Subjects: Information Theory
    Abstract

    We consider the regular model of formula generation in conjunctive normal
    form (CNF) introduced by Boufkhad et. al. We derive an upper bound on the
    satisfiability threshold and NAE-satisfiability threshold for regular random
    $k$-SAT for any $k \geq 3$. We show that these bounds matches with the
    corresponding bound for the uniform model of formula generation.

Math-arch

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