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A branch and bound algorithm for the two-machine flowshop problem with unit-time operations and time delays

Aziz Moukrim, Djamal Rebaine, Mehdi Serairi (2014)

RAIRO - Operations Research - Recherche Opérationnelle

In this paper we consider the problem of scheduling, on a two-machine flowshop, a set of unit-time operations subject to time delays with respect to the makespan. This problem is known to be 𝒩 P x1d4a9;x1d4ab; -hard in the strong sense. We propose an algorithm based on a branch and bound enumeration scheme. This algorithm includes the implementation of new lower and upper bound procedures, and dominance rules. A computer simulation to measure the performance of the algorithm is provided for a wide...

A DEA model for two-stage parallel-series production processes

Alireza Amirteimoori, Feng Yang (2014)

RAIRO - Operations Research - Recherche Opérationnelle

Data envelopment analysis (DEA) has been widely used to measure the performance of the operational units that convert multiple inputs into multiple outputs. In many real world scenarios, there are systems that have a two-stage network process with shared inputs used in both stages of productions. In this paper, the problem of evaluating the efficiency of a set of specialized and interdependent components that make up a large DMU is considered. In these processes the first stage consists of two parallel...

A distributed transportation simplex applied to a Content Distribution Network problem

Rafaelli de C. Coutinho, Lúcia M. A. Drummond, Yuri Frota (2014)

RAIRO - Operations Research - Recherche Opérationnelle

A Content Distribution Network (CDN) can be defined as an overlay system that replicates copies of contents at multiple points of a network, close to the final users, with the objective of improving data access. CDN technology is widely used for the distribution of large-sized contents, like in video streaming. In this paper we address the problem of finding the best server for each customer request in CDNs, in order to minimize the overall cost. We consider the problem as a transportation problem...

A linear programming based analysis of the CP-rank of completely positive matrices

Yingbo Li, Anton Kummert, Andreas Frommer (2004)

International Journal of Applied Mathematics and Computer Science

A real matrix A is said to be completely positive (CP) if it can be decomposed as A = BB^T, where the real matrix B has exclusively non-negative entries. Let k be the rank of A and Φ_k the least possible number of columns of the matrix B, the so-called completely positive rank (cp-rank) of A. The present work is devoted to a study of a general upper bound for the cp-rank of an arbitrary completely positive matrix A and its dependence on the ordinary rank k. This general upper bound of the cp-rank...

A modified algorithm for the strict feasibility problem

D. Benterki, B. Merikhi (2001)

RAIRO - Operations Research - Recherche Opérationnelle

In this note, we present a slight modification of an algorithm for the strict feasibility problem. This modification reduces the number of iterations.

Análisis interactivo de las soluciones del problema lineal múltiple ordenado.

Eduardo Conde Sánchez, Francisco Ramón Fernández García, Justo Puerto Albandoz (1994)


En este trabajo se estudian procedimientos para la elección entre las soluciones eficientes del Problema de Programación Lineal con Objetivos Múltiples, cuando el decisor manifiesta preferencias sobre ciertas ordenaciones de las valoraciones de las funciones objetivo, utilizándose como criterio de valoración global funciones basadas en el k-ésimo valor del vector de los objetivos ordenado en cada punto.Se desarrollan procedimientos para generar ordenaciones compatibles con la información del decisor....

Bounds on integrals with respect to multivariate copulas

Michael Preischl (2016)

Dependence Modeling

In this paper, we present a method to obtain upper and lower bounds on integrals with respect to copulas by solving the corresponding assignment problems (AP’s). In their 2014 paper, Hofer and Iacó proposed this approach for two dimensions and stated the generalization to arbitrary dimensons as an open problem. We will clarify the connection between copulas and AP’s and thus find an extension to the multidimensional case. Furthermore, we provide convergence statements and, as applications, we consider...

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