1,721,163 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
A penalty function heuristic for the resource constrained shortest path problem
No full textNorth-Hollan
Solving a fuel delivery problem by heuristic and exact approaches
No full textIn this paper we study the case of a company that delivers different types of fuel to a set of fuel pumps. The company has one warehouse and supplies the pumps by a fleet of trucks with several tanks of differing capacities.
The company’s aim is to satisfy the orders using the available resources (trucks and drivers) with the minimum total travel cost for delivery.
The problem has been formulated as a Set Partitioning model, solved by a Branch-and-Price algorithm. A fast combinatorial heuristic was adopted both to find a good feasible solution very quickly and to provide an initial set of columns for the Branch-and-Price algorithm.
Computational results are reported. The exactapproach shows low computation time for the real instances provided by the company
A state-of-the-art review on torque distribution strategies aimed at enhancing energy efficiency for fully electric vehicles with independently actuated drivetrains
No full textElectric vehicles are the future of private passenger transportation. However, there are still several technological barriers that hinder the large scale adoption of electric vehicles. In particular, their limited autonomy motivates studies on methods for improving the energy efficiency of electric vehicles so as to make them more attractive to the market. This paper provides a concise review on the current state-of-the-art of torque distribution strategies aimed at enhancing energy efficiency for fully electric vehicles with independently actuated drivetrains (FEVIADs). Starting from the operating principles, which include the "control allocation" problem, the peculiarities of each proposed solution are illustrated. All the existing techniques are categorized based on a selection of parameters deemed relevant to provide a comprehensive overview and understanding of the topic. Finally, future concerns and research perspectives for FEVIAD are discussed
Simple pattern minimality problems: Integer linear programming formulations and covering-based heuristic solving approaches
No full textThe simple pattern minimality problem (SPMP) represents a central problem in the logical analysis of data and association rules mining, and it finds applications in several fields as logic synthesis, reliability analysis, and automated reasoning. It consists of determining the minimum number of patterns explaining all the observations of a data set, that is, a Boolean logic formula that is true for all the elements of the data set and false for all the unseen observations. We refer to this problem as covering SPMP (C-SPMP), because each observation can be explained (covered) by more than one pattern. Starting from a real industrial application, we also define a new version of the problem, and we refer to it as partitioning SPMP (P-SPMP), because each observation has to be covered just once. Given a propositional formula or a truth table, C-SPMP and P-SPMP coincide exactly with the problem of determining the minimum disjunctive and minimum exclusive disjunctive normal form, respectively. Both problems are known to be NP-hard and have been generally tackled by heuristic methods. In this context, the contribution of this work is twofold. On one side, it provides two original integer linear programming formulations for the two variants of the SPMP. These formulations exploit the concept of Boolean hypercube to build a graph representation of the problems and allow to exactly solve instances with more than 1,000 observations by using an MIP solver. On the other side, two effective and fast heuristics are proposed to solve relevant size instances taken from literature (SeattleSNPs) and from the industrial database. The proposed methods do not suffer from the same dimensional drawbacks of the methods present in the literature and outperform either existing commercial and freeware logic tools or the available industrial solutions in the number of generated patterns and/or in the computational burden
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
