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Satisfiability and matchings in bipartite graphs: relationship and tractability.

Belaid Benhamou (2004)

RACSAM

Satisfiability problem is the task to establish either a given CNF logical formula admits a model or not. It is known to be the canonical NP-complete problem. We study in this note the relationship between matchings in bipartite graphs and the satisfiability problem, and prove that some restrictions of formulae including the known r-r-SAT1 class are trivially satisfiable. We present an algorithm which finds a model for such formulas in polynomial time complexity if one exists or, failing this, proves...

Scale Dependence of Contact Line Computations

O. Weinstein, L. M. Pismen (2008)

Mathematical Modelling of Natural Phenomena

The shape and velocity of a sliding droplet are computed by solving the Navier-Stokes equation with free interface boundary conditions. The Galerkin finite element method is implemented in a 2D computation domain discretized using an unstructured mesh with triangular elements. The mesh is refined recursively at the corners (contact points). The stationary sliding velocity is found to be strongly dependent on grid refinement, which is a consequence of the contact line singularity resolved through...

Scaling of model approximation errors and expected entropy distances

Guido F. Montúfar, Johannes Rauh (2014)

Kybernetika

We compute the expected value of the Kullback-Leibler divergence of various fundamental statistical models with respect to Dirichlet priors. For the uniform prior, the expected divergence of any model containing the uniform distribution is bounded by a constant 1 - γ . For the models that we consider this bound is approached as the cardinality of the sample space tends to infinity, if the model dimension remains relatively small. For Dirichlet priors with reasonable concentration parameters the expected...

Scheduling in the presence of processor networks : complexity and approximation

Vincent Boudet, Johanne Cohen, Rodolphe Giroudeau, Jean-Claude König (2012)

RAIRO - Operations Research

In this paper, we study the problem of makespan minimization for the multiprocessor scheduling problem in the presence of communication delays. The communication delay between two tasks i and j depends on the distance between the two processors on which these two tasks are executed. Lahlou shows that a simple polynomial-time algorithm exists when the length of the schedule is at most two (the problem becomes 𝒩𝒫-complete when the length of the schedule ...

Scheduling in the presence of processor networks : complexity and approximation

Vincent Boudet, Johanne Cohen, Rodolphe Giroudeau, Jean-Claude König (2012)

RAIRO - Operations Research

In this paper, we study the problem of makespan minimization for the multiprocessor scheduling problem in the presence of communication delays. The communication delay between two tasks i and j depends on the distance between the two processors on which these two tasks are executed. Lahlou shows that a simple polynomial-time algorithm exists when the length of the schedule is at most two (the problem becomes 𝒩𝒫-complete when the length of the schedule ...

Scheduling multiprocessor tasks on two parallel processors

Jacek Błażewicz, Paolo Dell'Olmo, Maciej Drozdowski (2002)

RAIRO - Operations Research - Recherche Opérationnelle

In this work scheduling multiprocessor tasks on two parallel identical processors is considered. Multiprocessor tasks can be executed by more than one processor at the same moment of time. We analyze scheduling unit execution time and preemptable tasks to minimize schedule length and maximum lateness. Cases with ready times, due-dates and precedence constraints are discussed.

Scheduling multiprocessor tasks on two parallel processors

Jacek Błażewicz, Paolo Dell'Olmo, Maciej Drozdowski (2010)

RAIRO - Operations Research

In this work scheduling multiprocessor tasks on two parallel identical processors is considered. Multiprocessor tasks can be executed by more than one processor at the same moment of time. We analyze scheduling unit execution time and preemptable tasks to minimize schedule length and maximum lateness. Cases with ready times, due-dates and precedence constraints are discussed.

Scheduling precedence task graphs with disturbances

Apurv Gupta, Gilles Parmentier, Denis Trystram (2003)

RAIRO - Operations Research - Recherche Opérationnelle

In this paper we consider the problem of scheduling precedence task graphs in parallel processing where there can be disturbances in computation and communication times. Such a phenomenon often occurs in practice, due to our inability to exactly predict the time because of system intrusion like cache miss and packet transmission time in mediums like ethernet etc. We propose a method based on the addition of some extra edges to protect the initial scheduling from performing badly due to such changes...

Scheduling Precedence Task Graphs with Disturbances

Apurv Gupta, Gilles Parmentier, Denis Trystram (2010)

RAIRO - Operations Research

In this paper we consider the problem of scheduling precedence task graphs in parallel processing where there can be disturbances in computation and communication times. Such a phenomenon often occurs in practice, due to our inability to exactly predict the time because of system intrusion like cache miss and packet transmission time in mediums like ethernet etc. We propose a method based on the addition of some extra edges to protect the initial scheduling from performing badly due to such...

Scheduling UET Trees with Communication Delays on two Processors

Frederic Guinand, Denis Trystman (2010)

RAIRO - Operations Research

In this paper, we present a new linear time algorithm for scheduling UECT (Unit Execution and Communication Time) trees on two identical processors. The chosen criterion is the makespan. The used strategy is based on clustering of tasks. We show that this algorithm builds optimal schedules. Some extensions are discussed for non UECT tasks.

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