1,721,154 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Get PDF“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
Integer linear programming for trust-region subproblems in integer optimal control with total variation regularization
No full textIn this work we concern ourselves with integer linear programs we obtain from a uniform discretization of subproblems arising in a trust-region algorithm for integer optimal control problems with total variation regularization. The underlying domain is either one-dimensional or two-dimensional and the control value set is a finite contiguous subset of the integers. We introduce several relaxations which not only provide lower bounds for our integer programming formulation but also allow us to obtain a conditional -approximation.
We provide NP-hardness results which show that a more general version of the integer program obtained from a non-uniform discretization of the trust-region subproblem is NP-hard by a reduction from the knapsack problem. Furthermore, we conjecture the NP-hardness of the two-dimensional case even with a binary control value set. We support this conjecture by providing a reduction from the minimum bisection problem for grid graphs with an arbitrary number of holes which has been conjectured to be NP-hard for several decades.
We show that the polyhedron of the linear programming relaxation has a very special property. For vertex solutions we prove that non-integer values can only be attained in entry combinations subject to structural restrictions which also enforce that the fractional value attained in each of these entries is identical. This property is reminiscent of the solution for the relaxed knapsack problem in which at most one entry is fractional.
For the one-dimensional case we are able to provide a shortest path approach for the more general case of a non-uniform discretization with a corresponding integer program. This provides a pseudo-polynomial algorithm. For the two-dimensional case we employ an integer programming solver instead. We can use the one-dimensional case to calculate as well as improve good feasible points which allows for a primal heuristic. Furthermore, we supply a simple branching priority derived from the one-dimensional case. Based on the special property of the polyhedron, we derive cutting planes which make use of a connection to graph-based problems as well as the so-called minimum cut ratio. Finally, we extend a decomposition approach for the overall trust-region algorithm.
We validate our approaches with several numerical examples and note significant run time improvements for the one-dimensional and two-dimensional cases. We discuss under which conditions our approaches are especially effective but also argue their limitations
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe 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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
Analysis, Quantification and Evaluation of Uncertainty
No full textThis chapter describes the various approaches to analyse, quantify and evaluate uncertainty along the phases of the product life cycle. It is based on the previous chapters that introduce a consistent classification of uncertainty and a holistic approach to master the uncertainty of technical systems in mechanical engineering. Here, the following topics are presented: the identification of uncertainty by modelling technical processes, the detection and handling of data-induced conflicts, the analysis, quantification and evaluation of model uncertainty as well as the representation and visualisation of uncertainty. The different approaches are discussed and demonstrated on exemplary technical systems
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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