135 research outputs found

    Fuzzy Multi-Agent Simulation of COVID-19 Pandemic Spreading

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    In this paper, we present a new approach for Covid-19 Pandemic spreading simulation based on fuzzy multi agents. The agent parameters consider distribution of the population according to age, and the index of socio-economic fragility. Medical knowledge affirms that the COVID-19 main risk factors are age and obesity. The worst medical situation is caused by the combination of these two risk factors which in almost99% of cases finish in ICU. The appearance of virus variants is another aspect parameter by our simulation through a simplified modeling of the contagiousness. Using real data from people from West Indies (Guadeloupe, F.W.I.), we modeled the infection rate of the risk population, if neither vaccination nor barrier gestures are respected. The results show that hospital capacities are exceeded, and the number of deaths exceeds 2% of the infected population, which is close to the reality

    Stopping criteria, forward and backward errors for perturbed asynchronous linear fixed point methods in finite precision

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    International audienceThis paper deals with perturbed linear fixed point methods in the presence of round off errors. Successive approximations as well as the more general, asynchronous iterations are treated. Forward and backward error estimates are presented and are used in order to propose theoretical stoppig criteria for these methods. In the case of asynchronous iterations, macro iterations are used as a tool in order to obtain estimates

    A new class of asynchronous iterative methods with order intervals

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    International audienceThis paper deals with a new class of parallel asynchronous iterative algorithms for the solution of nonlinear systems of equations. The main feature of the new class of methods preseted here is the possibility of flexible commmunication between processors. In particular partial updates can be exchanged. Approximation of the asssociated fixed point mapping is also considered. A detailed convergengence study is presented. A connection with the Schwarz alternating method is made for nonlinear boundary value problems. Computational results on a shared memory multiprocessotr IBM 3090 are presented

    Asynchronous iterations with flexible communication: contracting operators

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    AbstractThe concept of flexible communication permits one to model efficient asynchronous iterations on parallel computers. This concept is particularly useful in two practical situations. Firstly, when communications are requested while a processor has completed the current update only partly, and secondly, in the context of inner/outer iterations, when processors are also allowed to make use of intermediate results obtained during the inner iteration in other processors.In the general case of nonlinear or linear fixed point problems, we give a global convergence results for asynchronous iterations with flexible communication whereby the iteration operators satisfy certain contraction hypotheses. In this manner we extend to a contraction context previous results obtained for monotone operators with respect to a partial ordering

    Recent Advances on GPU Computing in Operations Research

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    Abstract-In the last decade, Graphics Processing Units (GPUs) have gained an increasing popularity as accelerators for High Performance Computing (HPC) applications. Recent GPUs are not only powerful graphics engines but also highly threaded parallel computing processors that can achieve sustainable speedup as compared with CPUs. In this context, researchers try to exploit the capability of this architecture to solve difficult problems in many domains in science and engineering. In this article, we present recent advances on GPU Computing in Operations Research. We focus in particular on Integer Programming and Linear Programming

    Recent Advances on GPU Computing in Operations Research

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    In the last decade, Graphics Processing Units (GPUs) have gained an increasing popularity as accelerators for High Performance Computing (HPC) applications. Recent GPUs are not only powerful graphics engines but also highly threaded parallel computing processors that can achieve sustainable speedup as compared with CPUs. In this context, researchers try to exploit the capability of this architecture to solve difficult problems in many domains in science and engineering. In this article, we present recent advances on GPU Computing in Operations Research. We focus in particular on Integer Programming and Linear Programming

    Parallelization of subdomain methods with overlapping for linear and nonlinear convection-diffusion problems

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    International audienceLinear and nonlinear convection-diffusion problems are considered. The numerical solution of these problems via the Schwarz alternating method is studied. A new class of parallel asynchronous iterative methods with flexible communication is applied. The implementation of parallel asyn-chronous and synchronous algorithms on distributed memory multiprocessors is described. Experimental results obtained on an IBM SP2 by using PVM are presented and analyzed. The interest of asynchronous iterative methods with flexible communication is clearly shown

    Mathematical study of perturbed asynchronous iterations designed for distributed termination

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    International audienceThis paper deals with the mathematical study of perturbed xed point asynchronous iterations designed for a distributed termination. The distributed termination of asynchronous iterations is considered by using a perturbed xed point mapping, which is an approximation of an exact xed point mapping. In the general framework of '-approximate contraction, it is shown that the perturbed asynchronous iteration converges in nite time and that the limit of the perturbed asynchronous iteration belongs to a ball of nite radius and center ~ u ? , solution of the exact problem. The value of the radius is given in the case of linear and quadratic convergence, respectively

    Asynchronous iterative algorithms with flexible communication for nonlinear network flow problems

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    International audienceThe strictly convex network flow problem is considered. The dual of this problem is unconstrained continuously differentiable and well suited for solution via parallel or distributed iterative algorithms.A new class of asynchronou iterative methods is proposed ; the asynchronous iterations with flexibl communication
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