1,721,345 research outputs found
A linear program for the two-hub location problem
No full textThis paper considers the discrete two-hub location problem, We need to choose two hubs from a set of nodes. The remaining nodes are to be connected to one of the two hubs which act as switching points for internodal flows. A configuration which minimizes the total flow cost needs to be found. We show that the problem can be solved in polynomial time when the hub locations are fixed. Since there are at most 1/2n(n-1) ways to choose the hub locations, the two-hub location problem can be solved in polynomial time. We transform the quadratic 0-1 integer program of the single allocation problem in the fixed two-hub system into a linear program and show that all extreme points of the polytope defined by the LP are integral. Also, the problem can be transformed into a minimum cut problem which can be solved efficiently by any polynomial time algorithm. (C) 1997 Elsevier Science B.V
The single allocation problem in the interacting three-hub network
No full textWe consider the single allocation problem in the interacting three-hub network with fixed hub locations, in the single allocation hub network, the hubs are fully interconnected and each nonhub node has to be connected to exactly one of the hubs. The flows between each pair of nodes are sent using the hubs as intermediate switching points. The problem is to find an optimal allocation of nonhub nodes to the hubs which minimizes the total flow cost. We show that the single allocation problem is NP-hard as soon as the number of hubs is three, although the problem in a two-hub system has polynomial time algorithms. This paper provides a mixed integer formulation of the problem and considers the polyhedral properties of it. The formulation can also be used for the single allocation problem with fixed costs for opening links, the three-terminal cut problem, and the three-processor distribution problem. Computational experiences are reported for data given in the literature and randomly generated problems. (C) 2000 John Wiley & Sons, Inc
Efficient solution procedure and reduced size formulations for p-hub location problems
No full textIn this paper we consider the uncapacitated p-hub location problems, where multiple and single allocation cases are considered. In the multiple allocation problem, a nonhub node may be allocated to more than one hub. We show that the multiple allocation problem can be solved efficiently by the shortest path algorithm when p is fixed. Also, this algorithm can be applied to the cases in which some other hubbing policies are used. In the single allocation problem, each nonhub node must be allocated to exactly one of the p hubs. We provide a reduced size formulation, and a mixed integer formulation for the model with fixed hub locations, where fixed costs for opening links are considered. Computational experience is provided using the data given in the literature and the instances having fixed costs for opening links. (C) 1998 Elsevier Science B.V. All rights reserved
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
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
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Scythropiodes MATSUMURA 1931
No full textGenus <i>Scythropiodes</i> Matsumura, 1931 <p> <i>Scythropiodes</i> Matsumura, 1931: 1099.</p> <p> Type species: <i>Scythropiodes seriatopunctata</i> Matsumura, 1931.</p>Published as part of <i>Sohn, J. - C., & Wu, S., 2023, A new species of the genus Scythropiodes Matsumura, 1931 (Lepodoptera: Peleopodidae) from Korea and Taiwan, pp. 1-5 in Far Eastern Entomologist 486</i> on page 2, DOI: 10.25221/fee.486.1, <a href="http://zenodo.org/record/10134792">http://zenodo.org/record/10134792</a>
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
- …
