1,721,017 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
Varietal and Monadic Completions
No full textConstruction of varietal and monadic completions. Characterization of abstract equivalence of (manysorted) (finitary) varieties via varietal and monadic completions
Wesentlich algebraische Beschreibungen lokal endlich präsentierbarer Kategorien
No full textLocal presentability has turned out to be one of the most fruitful concepts in category theory. The fact, that a category is locally finitely presentable iff it is equivalent to the category of models of an essentially algebraic, finitary theory, is widely known. Unfortunately, the existing approaches in literature are either unsatisfactory - with respect to existing examples and to the number of sorts - or even wrong. Now the aim of the main part of this thesis is to give an intuitive proof of the mentioned fact, which covers existing examples, and can be generalized to the non-finitary case under mild assumptions. Here the set of sorts of such a description of a locally finitely presentable category is given by a strong generator of finitely presentables in this category. Also, this construction provides a new approach to the known characterization of quasivarieties. Further, the theory constructed for a locally finitely presentable category is some kind of clone. A non-trivial example of a locally finitely presentable category with a managable strong generator of finitely presentables is given by the category of coalgebras for a polynomial set-endofunctor. In the second part of this dissertation we show that this category is even equivalent to some variety of unary algebras without equations. Moreover, we characterize polynomial set-endofunctors by the property that the corresponding category of coalgebras is concretely equivalent to some presheaf category. Finally, we introduce for an endofunctor the concept of polynomiality w.r.t. a family of functors, and show that - under certain assumptions - several constructions and properties can be lifted to the corresponding category of coalgebras
Morita Equivalence for Unary Varieties
No full textThe problem of determining all varieties W (categorically) equivalent to a given variety V, which Isbell first posed in the early 1970´s, has been addressed in numerous ways. McKenzie (1996) and Porst (2000) describe a general solution consisting of a two step construction. For a given variety V, first its n-th matrix powers are constructed for natural numbers n, and then McKenzie´s u-modification for idempotent and invertible terms u is applied to the matrix powers. Thus, one obtains all varieties equivalent to V. This thesis contains new descriptions for the matrix power of a (finitary) variety and for its u-modification. The syntax of these new constructions is considerably simpler than the syntax of the original constructions. The matrix power of an arbitrary variety V is characterized by adding just one binary operation to the original operations of the given variety V as well as adding equations to the original ones. The u-modification is more elusive and we have to restrict ourselves to the unary case. A solution is given for a large class of unary varieties. Again a characterization is obtained by adding operations and equations to the originally given ones. Furthermore some special cases like the variety of Boolean algebras and the variety of sets are treated as illustrating examples
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
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
Is the Construct of l-Topological Spaces a Co-Tower Extension of Some Simpler Construct?
No full textIn an earlier paper, the second author associated with any
fibre-small topological construct A and any completely distributive
lattice L, an extension of A, called the (L)-co-tower
extension of A. He demonstrated that many familiar constructs
in fuzzy topology can be expressed as co-tower extensions of more basic constructs
and asked
whether the construct L-Top of L-topological spaces (the stratified
Chang-Goguen spaces) can be expressed as a co-tower extension. In this note
we answer this question with "no" and "yes". In particular we present the following
theorems:
(1) If L is a 3-element linearly ordered lattice (or, more generally,
any linearly ordered finite lattice with at least 3 elements), then L-Top cannot be expressed as an L-co-tower extension.
(2) If L is a 4-element Boolean algebra (or, more generally, any
atomic complete Boolean algebra), then L-Top is (up to concrete
isomorphism) the L-co-tower extension of the construct Top of
topological spaces. Mathematics Subject Classification (1991): 54B30, 54A40, 18B30 Keywords: topological construct, L-Topological space, co-tower extension,
completely distributive lattice, categorical methods, fuzzy topology, categories
of topological spaces and continuous mappings, distributive, lattice, extensions,
Boolean algebra, algebra, complete, topological space Quaestiones Mathematicae
24(2) 2001, 147-15
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