New efficient constructive heuristics for the hybrid flowshop to minimise makespan: A computational evaluation of heuristics

This paper addresses the hybrid flow shop scheduling problem to minimise makespan, a well-known scheduling problem for which many constructive heuristics have been proposed in the literature. Nevertheless, the state of the art is not clear due to partial or non homogeneous comparisons. In this paper, we review these heuristics and perform a comprehensive computational evaluation to determine which are the most efficient ones. A total of 20 heuristics are implemented and compared in this study. In addition, we propose four new heuristics for the problem. Firstly, two memory-based constructive heuristics are proposed, where a sequence is constructed by inserting jobs one by one in a partial sequence. The most promising insertions tested are kept in a list. However, in contrast to the Tabu search, these insertions are repeated in future iterations instead of forbidding them. Secondly, we propose two constructive heuristics based on Johnson’s algorithm for the permutation flowshop scheduling problem. The computational results carried out on an extensive testbed show that the new proposals outperform the existing heuristics.Ministerio de Ciencia e Innovación DPI2016-80750-

Interdisciplinariedad en ciencias sociales: perspectivas abiertas por la obra de Pierre Bourdieu

La compleja obra de Pierre Bourdieu representa una de las propuestas más imaginativas y fecundas para un proyecto interdisciplinar en ciencias sociales. La hipótesis que pretendo desarrollar en este artículo es que la fuerza de esta mirada sociológica sobre el mundo social radica en una teoría de la práctica que proporciona unidad a las investigaciones en los campos más diversos, da identidad a su modus operandi y es la fuente de inspiración para muchos investigadores de diferentes disciplinas sociales y de las más diversas procedencias geográficas. El método que he empleado es una exploración selectiva y crítica de la producción científica del sociólogo francés

Efficient heuristics for the hybrid flow shop scheduling problem with missing operations

In this paper, we address the hybrid flowshop scheduling problem for makespan minimisation. More specifically, we are interested in the special case where there are missing operations, i.e. some stages are skipped, a condition inspired in a realistic problem found in a plastic manufacturer. The main contribution of our paper is twofold. On the one hand we carry out a computational analysis to study the hardness of the hybrid flowshop scheduling problem with missing operations as compared to the classical hybrid flowshop problem. On the other hand, we propose a set of heuristics that captures some special features of the missing operations and compare these algorithms with already existing heuristics for the classical hybrid flowshop, and for the hybrid flowshop problem with missing operations. The extensive computational experience carried out shows that our proposal outperforms existing methods for the problem, indicating that it is possible to improve the makespan by interacting with the jobs with missing operations.Ministerio de Ciencia e Innovación DPI2016-80750-

Capital simbólico, dominación y legitimidad. Las raíces weberianas de la sociología de Pierre Bourdieu

La noción de capital simbólico es uno de los conceptos más complejos construidos por Pierre Bourdieu. Este artículo ofrece un análisis crítico de su origen, significado y funciones. En él se explora el uso que hizo de este concepto en sus investigaciones sobre las distintas formas de dominación, los campos de producción simbólica, el campo burocrático, las estrategias simbólicas de las clases dominantes y las luchas simbólicas por la hegemonía en la sociedad global. Aunque muestra relevantes semejanzas con los conceptos weberianos de carisma y legitimidad, la noción de capital simbólico sólo puede comprenderse adecuadamente en relación con los otros conceptos centrales de la economía de la práctica de Bourdieu, en la que es usado como un instrumento heurístico para articular las dimensiones subjetiva y objetiva de cualquier fenómeno social.The notion of symbolic capital is one of the most complex concepts constructed by Pierre Bourdieu. This paper provides a critical analysis of its origin, meaning and functions. It explores the use that Bourdieu made of symbolic capital in his research on different forms of domination, the market of symbolic goods, the bureaucratic field, the symbolic strategies of the dominant classes, and the symbolic struggles for hegemony in the global society. Despite its strong similarities with the Weberian concepts of charisma and legitimacy, the notion of symbolic capital can only be appropriately understood in relation to the other core concepts of Bourdieu's general economy of practice, in which it is used as a heuristic instrument to articulate the subjective and objective dimensions of any social phenomenon

A bounded-search iterated greedy algorithm for the distributed permutation flowshop scheduling problem

As the interest of practitioners and researchers in scheduling in a multi-factory environment is growing, there is an increasing need to provide efficient algorithms for this type of decision problems, characterised by simultaneously addressing the assignment of jobs to different factories/workshops and their subsequent scheduling. Here we address the so-called distributed permutation flowshop scheduling problem, in which a set of jobs has to be scheduled over a number of identical factories, each one with its machines arranged as a flowshop. Several heuristics have been designed for this problem, although there is no direct comparison among them. In this paper, we propose a new heuristic which exploits the specific structure of the problem. The computational experience carried out on a well-known testbed shows that the proposed heuristic outperforms existing state-of-the-art heuristics, being able to obtain better upper bounds for more than one quarter of the problems in the testbed.Ministerio de Ciencia e Innovación DPI2010-15573/DP

A beam-search-based constructive heuristic for the PFSP to minimise total flowtime

In this paper we present a beam-search-based constructive heuristic to solve the permutation flowshop scheduling problem with total flowtime minimisation as objective. This well-known problem is NP-hard, and several heuristics have been developed in the literature. The proposed algorithm is inspired in the logic of the beam search, although it remains a fast constructive heuristic. The results obtained by the proposed algorithm outperform those obtained by other constructive heuristics in the literature for the problem, thus modifying substantially the state-of-the-art of efficient approximate procedures for the problem. In addition, the proposed algorithm even outperforms two of the best metaheuristics for many instances of the problem, using much lesser computation effort. The excellent performance of the proposal is also proved by the fact that the new heuristic found new best upper bounds for 35 of the 120 instances in Taillard’s benchmark.Ministerio de Ciencia e Innovación DPI2013-44461-PMinisterio de Ciencia e Innovación DPI2016-80750-