Search results for "Abstract"

Application of graph grammars in music composing systems

1987

Optimal Tree Decompositions Revisited: A Simpler Linear-Time FPT Algorithm

2020

In 1996, Bodlaender showed the celebrated result that an optimal tree decomposition of a graph of bounded treewidth can be found in linear time. The algorithm is based on an algorithm of Bodlaender and Kloks that computes an optimal tree decomposition given a non-optimal tree decomposition of bounded width. Both algorithms, in particular the second, are hardly accessible. We present the second algorithm in a much simpler way in this paper and refer to an extended version for the first. In our description of the second algorithm, we start by explaining how all tree decompositions of subtrees defined by the nodes of the given tree decomposition can be enumerated. We group tree decompositions …

Solving a large multicontainer loading problem in the car manufacturing industry

2017

Abstract Renault, a large car manufacturer with factories all over the world, has a production system in which not every factory produces all the parts required to assemble a vehicle. Every day, large quantities of car parts are sent from one factory to another, defining very large truck/container transportation problems. The main challenge faced by the Renault logistics platforms is to load the items into trucks and containers as efficiently as possible so as to minimize the number of vehicles sent. Therefore, the problem to be solved is a multicontainer loading problem in which, besides the usual geometric constraints preventing items from overlapping and exceeding the dimensions of the c…

Mathematical models for Multi Container Loading Problems with practical constraints

2019

Abstract We address the multi container loading problem of a company that serves its customers’ orders by building pallets with the required products and loading them into trucks. The problem is solved by using integer linear models. To be useful in practice, our models consider three types of constraints: geometric constraints, so that pallets lie completely inside the trucks and do not overlap; weight constraints, defining the maximum weights supported by a truck and by each axle, as well as the position of the centre of gravity of the cargo; and dynamic stability constraints. These last constraints forbid empty spaces between pallets to avoid cargo displacement when the truck is moving, …

The Multi-period Multi-trip Container Drayage Problem with Release and Due Dates

2021

Abstract The Container Drayage Problem (CDP) aims at routing a fleet of trucks, based at a common terminal, to serve customers while minimizing the total travel distance. Each trip starts from and ends at the terminal, and handles a subset of customers. Each customer requires either that a container is picked up or delivered. We introduce a more realistic variant, i.e., the Multi-trip Multi-period CDP with Release and Due Dates (MM-CDP-RDD), in which the planning horizon is composed of several periods (days). On each day, each truck may perform more than one trip respecting the Release and Due Dates (RDD) associated with customer services, corresponding to the first and the last day on whic…

JSSPrediction: a Framework to Predict Protein Secondary Structures Using Integration

2006

Identifying protein secondary structures is a difficult task. Recently, a lot of software tools for protein secondary structure prediction have been produced and made available on-line, mostly with good performances. However, prediction tools work correctly for families of proteins, such that users have to know which predictor to use for a given unknown protein. We propose a framework to improve secondary structure prediction by integrating results obtained from a set of available predictors. Our contribution consists in the definition of a two phase approach: (i) select a set of predictors which have good performances with the unknown protein family, and (ii) integrate the prediction resul…

Photo Induced Radical Reactions

2012

This article discusses a number of reactions of potential synthetic interest occurring through photochemically generated organic radicals. Emphasis is placed on the nature of the resulting photoproducts, whose formation is discussed on a mechanistic basis. If available, experimental evidence (obtained by laser flash photolysis or related time-resolved techniques) is provided. The material is organized according to the reaction types, for instance, homolytic cleavage, mesolytic cleavage, radical addition, and oxidative or reductive electron transfer. In addition to the classical carboncarbon or carbonhydrogen bond breaking processes, such as the Norrish type I reaction, the hydrogen abstract…

Spacing and Organizing: Process Approaches to the Study of Organizational Space

2018

In the past several decades, the research on space in management studies has moved from being an implicit idea to becoming an important generative force in organizational theory. Through this turn, space no longer surfaces as a stable container in which organizing occurs, rather it is a process for enacting organizing. Even with the growth of studies on organizational space, only a modicum of work exists that aims to distill and theorize the notion of space as organizing. This paper sets forth a typology of process studies on organizational space linked to two dimensions and five approaches for conceiving of space as organizing. In offering this typology, it not only provides an overview of…

Cy Twombly: Herencia Mediterránea

2013

Cuando hablamos de literatura, música, historia o arte es inherente retrotraerse a la cuna de nuestra cultura, el Mediterráneo. El historiador francés Fernand Braudel (1902-1985) -padre de la historia del Mediterráneo- comentaba que el concepto en sí constituye el acercamiento no solo histórico sino intelectual, en su sentido más extendido, de una identidad propia,forjada durante siglos gracias a los testimonios de algunas de las personalidades más importantes de la historia: el poeta lírico griego Arquíloco (ca. 680 a. C. - ca. 645 a.C.), el historiador y filósofo griego Jenofonte (ca.431 a. C. - 354 a. C.), los poetas latinos Gayo Valerio Catulo (87 a. C. - 57 a. C) y Virgilio (70 a. C. -…

Anàlisi categorial

2004

Si durant la primera meitat del nostre segle la filosofia científica es caracteritzà per un recel envers l'especulació filosòfica, recel emparat en la concepció de la filosofia com a «sintaxi lògica» i en el dogma del principi de verificació, a la segona meitat del segle es pot observar un major classicisme en la investigació filosòfica d'aquest corrent: vells temes de la tradició recobren interès i criden l'atenció dels filòsofs del nostre temps; la intricada qüestió dels universals, la determinació ontològica del que hi ha, la naturalesa de les entitats abstractes, el problema de l'innatisme ... són, entre d'altres, velles qüestions a què la filosofia analítica i científica actual ret un …