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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
Some problems in combinatorial geometry
Get PDFThis thesis is in two parts. The first two chapters deal with infinite matroids and the remaining three chapters with finite matroids. Chapter 1 has two main results. Firstly we prove that there is no duality function on the class of independence spaces which behaves like duality for finite matroids. Secondly we determine the unique class of preindependence spaces which contains the class of independence spaces and is closed under restriction, contraction and the natural duality function. Two other results of this chapter answer questions of Higgs and Welsh on infinite matroids. The main result of Chapter 2 is a counter-example to a 1967 conjecture of Nash-Williams concerning packing disjoint spanning trees in countably infinite graphs. In the third chapter we prove matroid analogues of various bounds on the chromatic number of a graph due to Matula, Szekeres and Wilf, and Brooks. These matroid results sharpen earlier bounds of Heron and Lindstrőm. In the second half of the chapter we answer a number of questions of Mullin and Stanton related to the critical problem for binary matroids. In Chapter 4 we prove the binary case of a matroid conjecture of Welsh which is a natural analogue of Gallai's theorem that the vertex-stability and vertex-covering numbers of a graph G sum to the number of vertices of G. The Tutte polynomial of a graph is known to be related to the bond percolation model on the graph. In Chapter 5 we introduce a basic abstraction of classical percolation theory, namely percolation on clutters. We give new and simpler proofs of several results of Hammersley and bound the percolation probability above and below. One of the main results shows that the theory of the Tutte polynomial cannot be extended from matroids to arbitrary clutters
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
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
Euler and bipartite matroids
No full textAbstractWe show that for binary matroids the properties of being Euler and bipartite are dual concepts, thus generalizing Euler's theorem for graphs
The random cluster process
No full textAbstractThe random cluster model is an intriguing stochastic model on the vertices and edges of a graph. It contains the ingredients of colouring problems on the vertices and at the same time percolation-type processes on the edge set. Thus it can be regarded as a correlated version of random graph theory. In this paper I relate the model to other more well-known areas of combinatorics
Generalized versions of Hall's theorem
No full textAbstractI show how a reduction principle technique used by Rado [11] in his very short elegant proof of Hall's theorem [2] may be used to give more general versions of Hall's theorem. Conditions are given for a family of sets to have both a system of representatives and a transversal on which an integer valued submodular function μ takes desired values. By suitably choosing μ we deduce several other well-known theorems in transversal theory
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
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