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Metasearch information fusion using linear programming

Gholam R. Amin, Ali Emrouznejad, Hamid Sadeghi (2012)

RAIRO - Operations Research

For a specific query merging the returned results from multiple search engines, in the form of a metasearch aggregation, can provide significant improvement in the quality of relevant documents. This paper suggests a minimax linear programming (LP) formulation for fusion of multiple search engines results. The paper proposes a weighting method to include the importance weights of the underlying search engines. This is a two-phase approach which in...

Méthode d'aide à la décision sur des évaluations multicritères par plusieurs juges

C. Vidal, A. Yehia Alcoutlabi (1990)

Mathématiques et Sciences Humaines

L'évaluation multicritère est un problème bien connu souvent traité par des méthodes de surclassement. Nous avons ici envisagé le cas général de plusieurs juges et agrégé les différentes évaluations pour construire une matrice de préférences, ramenant ainsi le problème à un problème de comparaisons par paires. Nous avons cherché des solutions optimales de classement en appliquant un algorithme d'affectation quadratique particulier.

Método primal dual para modelos de planificación con costes cóncavos y limitaciones de capacidad.

Luis Onieva, S. Lozano, Juan Carlos Larrañeta Astola, Rafael Ruiz Usano (1987)

Qüestiió

Este trabajo estudia el problema de planificación de la producción representado por un modelo de costes cóncavos sujeto a limitaciones de capacidad. La relajación lineal del modelo es analizada usando un enfoque primal-dual. Las soluciones del dual se obtienen resolviendo para cada producto modelos sin restricciones de capacidad asignando un precio a las mismas. El primal reducido supone un test de admisibilidad de dichas soluciones. El dual reducido permite calcular los nuevos precios recomendados...

Minimization of a convex quadratic function subject to separable conical constraints in granular dynamics

Pospíšil, Lukáš, Dostál, Zdeněk (2015)

Programs and Algorithms of Numerical Mathematics

The numerical solution of granular dynamics problems with Coulomb friction leads to the problem of minimizing a convex quadratic function with semidefinite Hessian subject to a separable conical constraints. In this paper, we are interested in the numerical solution of this problem. We suggest a modification of an active-set optimal quadratic programming algorithm. The number of projection steps is decreased by using a projected Barzilai-Borwein method. In the numerical experiment, we compare our...

Minimizing the earliness and tardiness cost of a sequence of tasks on a single machine

Philippe Chrétienne (2001)

RAIRO - Operations Research - Recherche Opérationnelle

Assume that n tasks must be processed by one machine in a fixed sequence. The processing time, the preferred starting time and the earliness and tardiness costs per time unit are known for each task. The problem is to allocate each task a starting time such that the total cost incurred by the early and tardy tasks is minimum. Garey et al. have proposed a nice O ( n log n ) algorithm for the special case of symmetric and task-independent costs. In this paper we first extend that algorithm to the case of asymmetric...

Minimizing the Earliness and Tardiness Cost of a Sequence of Tasks on a Single Machine

Philippe Chrétienne (2010)

RAIRO - Operations Research

Assume that n tasks must be processed by one machine in a fixed sequence. The processing time, the preferred starting time and the earliness and tardiness costs per time unit are known for each task. The problem is to allocate each task a starting time such that the total cost incurred by the early and tardy tasks is minimum. Garey et al. have proposed a nice O(nlogn) algorithm for the special case of symmetric and task-independent costs. In this paper we first extend that algorithm to the...

Minimizing the fuel consumption of a vehicle from the Shell Eco-marathon: a numerical study

Sophie Jan (2013)

ESAIM: Control, Optimisation and Calculus of Variations

We apply four different methods to study an intrinsically bang-bang optimal control problem. We study first a relaxed problem that we solve with a naive nonlinear programming approach. Since these preliminary results reveal singular arcs, we then use Pontryagin’s Minimum Principle and apply multiple indirect shooting methods combined with homotopy approach to obtain an accurate solution of the relaxed problem. Finally, in order to recover a purely bang-bang solution for the original problem, we...

Non-parametric approximation of non-anticipativity constraints in scenario-based multistage stochastic programming

Jean-Sébastien Roy, Arnaud Lenoir (2008)

Kybernetika

We propose two methods to solve multistage stochastic programs when only a (large) finite set of scenarios is available. The usual scenario tree construction to represent non-anticipativity constraints is replaced by alternative discretization schemes coming from non-parametric estimation ideas. In the first method, a penalty term is added to the objective so as to enforce the closeness between decision variables and the Nadaraya–Watson estimation of their conditional expectation. A numerical application...

Numerical modelling of semi-coercive beam problem with unilateral elastic subsoil of Winkler's type

Stanislav Sysala (2010)

Applications of Mathematics

A non-linear semi-coercive beam problem is solved in this article. Suitable numerical methods are presented and their uniform convergence properties with respect to the finite element discretization parameter are proved here. The methods are based on the minimization of the total energy functional, where the descent directions of the functional are searched by solving the linear problems with a beam on bilateral elastic ``springs''. The influence of external loads on the convergence properties is...

On finding optimal parameters of an oscillatory model of handwriting

Gaëtan André, Frédéric Messine (2014)

RAIRO - Operations Research - Recherche Opérationnelle

In this paper, we show how optimization methods can be used efficiently to determine the parameters of an oscillatory model of handwriting. Because these methods have to be used in real-time applications, this involves that the optimization problems must be rapidely solved. Hence, we developed an original heuristic algorithm, named FHA. This code was validated by comparing it (accuracy/CPU-times) with a multistart method based on Trust Region Reflective algorithm.

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