1,720,991 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
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
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
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
Ominaisarvoanalyysin geometrinen tulkinta
No full textThis thesis clarifies certain aspects of non-linear eigenanalysis with the help of differential geometry tools. Non-linear eigenproblems are generalizations of the linear eigenproblem that comprise higher order terms with respect to the bifurcation parameter. They arise from singularity investigations of dynamical system equilibrium sets: for a vast majority of physical problems, the eigenspace associated to the eigenproblem gives, precisely, the bifurcating direction at the singular point.
The research question consists in assessing the sensitivity of the eigenspace with respect to a prescribed variation of internal parameters of the defining dynamical system. A possible source of variation comes from using the linear predictor instead of the original non-linear eigenproblem. One of the questions an answer shall be given to, consists in assessing the difference between two eigenspaces: one given by the linear predictor and the other given by the original non-linear eigenproblem.
The tools used are taken from differential geometry. The parameter dependent Jacobian matrix evaluated at the primary equilibrium branch defines the non-linear eigenproblem. Geometrically, it can be interpreted as a smooth curve, called the Jacobian curve, that evolutes in the ambient matrix space. At a bifurcation point, the Jacobian matrix is rank deficient, by definition. Hence, the geometric interpretation of a nonlinear eigenproblem is the intersection of the Jacobian curve with the fixed rank matrix submanifold embedded in the ambient matrix space. The intersection point constitutes, therefore, a reference point on the fixed rank matrix manifold, around which one can draw a sphere of given radius computed with respect to the Riemannian distance function.
The geometric interpretation of the eigenproblem enables the eigenspace associated with the eigenproblem to be considered as a smooth map, called the eigenspace map. It is defined on the fixed rank matrix manifold and has values in the projective space. Sensitivity analysis of the eigenspace map consists, then, in computing the ratio of two distances. The first distance, which is located in the denominator of the ratio, is the Riemannian distance on the fixed rank matrix manifold between the centre point and a point on the sphere. It is, by definition, equal to the radius of the sphere. The second distance, located in the numerator of the ratio, is the distance, in the projective space, between the corresponding two image points by the eigenspace map. Numerical examples are given at the end of the work to illustrate the use of eigenspace sensitivity analysis in the context of structural stability.Väitöstyössä selvennetään differentiaaligeometrian menetelmin epälineaarisen ominaisarvoanalyysin aspekteja. Epälineaarinen ominaisarvotehtävä on yleistys lineaarisesta ominaisarvotehtävästä siten, että bifurkaatioparametrin suhteen korkeampaa astetta olevat matriisitermit otetaan huomioon. Kyseinen tehtävä esiintyy dynaamisten systeemien tasapainopistejoukkojen singulaarisuustarkasteluissa, sillä suurelle osalle fysikaalisista ongelmista ominaisarvotehtävään liittyvä ominaisavaruus antaa bifurkoivan suunnan sigulaaripisteeseen piirretyllä tangenttikartiolla.
Keskeiseksi tutkimusongelmaksi nousee siten ominaisavaruuden herkkyys dynaamisen systeemin sisäisten parametrien vaihtelulle. Tässä työssä tarkastellaan erityisesti tapausta, jossa parametrien vaihtelu liittyy siihen, että epälineaarisen ominaisarvotehtävän sijaan käytetään linearisoitua ominaisarvotehtävää. Näin ollen on tärkeää tietää kuinka paljon linearisoidun ominaisarvotehtävän ominaisavaruus poikkeaa epälineaarisen ominaisarvotehtävän ominaisavaruudesta.
Differentiaaligeometrian työkaluilla on työssä olennainen rooli. Bifurkaatioparametrista riippuva tasapainofunktioiden jakobiaanimatriisi evaluoidaan primääritasapainopolulla ja se määrittää ominaisarvotehtävän. Parametririippuva jakobiaanimatriisi voidaan geometrisesti tulkita sileäksi käyräksi matriisiavaruudessa, jakobiaanikäyräksi. Bifurkaatiopisteessä jakobiaani on rangivajaa, joten geometrisesti epälineaarinen ominaisarvotehtävä voidaan tulkita matriisiavaruuteen upotetun jakobiaanikäyrän ja vakiorangimatriisimoniston leikkauspisteeksi. Tätä leikkauspistettä voidaan ajatella keskipisteeksi vakiorangimatriisimonistolle piirretyle pallolle, jossa monistolla olevien pisteiden väliset etäisyydet lasketaan Riemannin etäisyysfunktion avulla.
Ominaisarvoanalyysin geometrinen tulkinta mahdollistaa sen, että ominaisavaruutta voidaan tarkastella sileänä kuvauksena - ominaisavaruuskuvauksena - vakiorangimatriisimonistolta projektiiviseen avaruuteen. Tästä seuraa, että ominaisavaruuskuvauksen herkkyys määritellään kahden etäisyyden osamääränä. Nimittäjässä on Riemannin etäisyys pallon keskipisteestä reunapisteelle, eli pallon säde. Osoittajassa taas on etäisyys projektiivisessa avaruudessa vastaaville ominaisavaruuksille. Työn lopussa annetaan numeerisia esimerkkejä kuinka soveltaa ominaisarvokuvauksen herkkyysanalyysiä rakenteiden stabiiliusongelmiin
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