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Distributed fuzzy decision making for production scheduling.

Thomas A. Runkler, Rudolf Sollacher, Wendelin Reverey (2004)

Mathware and Soft Computing

In production systems, input materials (educts) pass through multiple sequential stages until they become a product. The production stages consist of different machines with various dynamic characteristics. The coupling of those machines is a non-linear distributed system. With a distributed control system based on a multi-agent approach, the production system can achieve (almost) maximum output, where lot size and lot sequence are the most important control variables. In most production processes...

Eigenspace of a circulant max–min matrix

Martin Gavalec, Hana Tomášková (2010)

Kybernetika

The eigenproblem of a circulant matrix in max-min algebra is investigated. Complete characterization of the eigenspace structure of a circulant matrix is given by describing all possible types of eigenvectors in detail.

Erlang distributed activity times in stochastic activity networks

Yousry H. Abdelkader (2003)

Kybernetika

It is assumed that activity times in stochastic activity networks (SANs) are independent Erlang random variable (r.v.). A recurrence method of determining the k th moments of the completion time is presented. Applications are provided for illustration and are used to evaluate the applicability and appropriateness of the Erlang model to represent activity network.

Estudio computacional de algunos nuevos algoritmos heurísticos para el problema de planificación de proyectos con limitación de recursos.

Ramón Alvarez-Olaguibel, José Manuel Tamarit Goerlich, Vicente Valls Verdejo (1988)

Trabajos de Investigación Operativa

El trabajo describe dos métodos de diseño de algoritmos heurísticos para el problema de planificación de un proyecto con limitación de recursos. El primer método es constructivo: las actividades del proyecto se intentan incorporar a la secuencia posible tan pronto como lo permiten sus relaciones de precedencia, resolviendo de diversas formas los conflictos provocados por la limitación de recursos. El segundo enfoque está basado en la idea de incorporar arcos disjuntos para resolver las incompatibilidades...

Evolutionary algorithms for job-shop scheduling

Khaled Mesghouni, Slim Hammadi, Pierre Borne (2004)

International Journal of Applied Mathematics and Computer Science

This paper explains how to use Evolutionary Algorithms (EA) to deal with a flexible job shop scheduling problem, especially minimizing the makespan. The Job-shop Scheduling Problem (JSP) is one of the most difficult problems, as it is classified as an NP-complete one (Carlier and Chretienne, 1988; Garey and Johnson, 1979). In many cases, the combination of goals and resources exponentially increases the search space, and thus the generation of consistently good scheduling is particularly difficult...

Flow Polyhedra and Resource Constrained Project Scheduling Problems

Alain Quilliot, Hélène Toussaint (2012)

RAIRO - Operations Research - Recherche Opérationnelle

This paper aims at describing the way Flow machinery may be used in order to deal with Resource Constrained Project Scheduling Problems (RCPSP). In order to do it, it first introduces the Timed Flow Polyhedron related to a RCPSP instance. Next it states several structural results related to connectivity and to cut management. It keeps on with a description of the way this framework gives rise to a generic Insertion operator, which enables programmers to design greedy and local search algorithms....

France Telecom workforce scheduling problem: a challenge

Sebastian Pokutta, Gautier Stauffer (2009)

RAIRO - Operations Research

In this paper, we describe the methodology used to tackle France Telecom workforce scheduling problem (the subject of the Roadef Challenge 2007) and we report the results obtained on the different data sets provided for the competition. Since the problem at hand appears to be NP-hard and due to the high dimensions of the instance sets, we use a two-step heuristical approach. We first devise a problem-tailored heuristic that provides good feasible solutions and then we use a meta-heuristic scheme...

Généralisation max-plus des bornes de Lageweg, Lenstra et Rinnooy Kan

Christophe Lenté, Jean-Louis Bouquard (2003)

RAIRO - Operations Research - Recherche Opérationnelle

Le traditionnel problème d’ordonnancement de type flowshop se généralise en un problème d’optimisation matricielle dans l’algèbre Max-Plus. Une famille de bornes inférieures est présentée pour ce nouveau problème et la preuve est apportée que ces bornes généralisent les bornes de Lageweg et al.

Généralisation Max-Plus des bornes de Lageweg, Lenstra et Rinnooy Kan

Christophe Lenté, Jean-Louis Bouquard (2010)

RAIRO - Operations Research

Le traditionnel problème d'ordonnancement de type flowshop se généralise en un problème d'optimisation matricielle dans l'algèbre Max-Plus. Une famille de bornes inférieures est présentée pour ce nouveau problème et la preuve est apportée que ces bornes généralisent les bornes de Lageweg et al.

How to eliminate non-positive circuits in periodic scheduling: a proactive strategy based on shortest path equations

Sid-Ahmed-Ali Touati, Sébastien Briais, Karine Deschinkel (2013)

RAIRO - Operations Research - Recherche Opérationnelle

Usual periodic scheduling problems deal with precedence constraints having non-negative latencies. This seems a natural way for modelling scheduling problems, since task delays are generally non-negative quantities. However, in some cases, we need to consider edges latencies that do not only model task latencies, but model other precedence constraints. For instance in register optimisation problems devoted to optimising compilation, a generic machine or processor model can allow considering access...

Hybrid flow-shop with adjustment

Jan Pelikán (2011)

Kybernetika

The subject of this paper is a flow-shop based on a case study aimed at the optimisation of ordering production jobs in mechanical engineering, in order to minimize the overall processing time, the makespan. The production jobs are processed by machines, and each job is assigned to a certain machine for technological reasons. Before processing a job, the machine has to be adjusted; there is only one adjuster who adjusts all of the machines. This problem is treated as a hybrid two-stage flow-shop:...

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