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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
Pulssitettujen satunnaisten säteiden polarisaatio
Full text linkValon polarisaatiolla on monitahoinen matemaattinen rakenne sekä suuri määrä hyödyntämiskohteita eri tieteen ja tekniikan alueilla, kuten lähikenttäoptiikassa, valon ja aineen vuorovaikutuksessa sekä optisessa tiedonsiirrossa. Valonsäteiden polarisaatiota on tutkittu laajasti satunnaisten, tilastollisesti stationaaristen säteiden osalta, mutta tähän mennessä pulssitettujen säteiden osittaisen polarisaation kuvaamiseen ei ole kehitetty johdonmukaista, kattavaa teoriaa.
Työn aluksi esitellään stationaaristen kenttien kuvaamiseen käytetty polarisaatioformalismi aikatasossa polarisaatiomatriisin ja taajuustasossa ristispektrimatriisin (crossspectral density matrix, CSD) avulla. Stationaaristen kenttien polarisaatioteorian kertaamisen jälkeen työn pääasiallisessa osuudessa kehitetään polarisaatiomatriisiformalismi ei-stationaarisille kentille aika- ja taajuustasoissa. Aika- ja taajuustason polarisaation välille johdetaan yhteys, jota analysoidaan mitattavissa olevien aika- ja taajuustasojen suureiden, polarisaatioasteen ja Stokesin parametrien, avulla. Valopulssin polarisaatioasteen ja -tilan muuttumista ajan ja taajuuden funktiona havainnollistetaan esimerkein. Yksi esimerkeistä kuvaa pulssia, jonka aikatason polarisaatioastetta ja -tilaa voidaan muokata halutulla tavalla pulssin pysyessä kuitenkin taajuustasossa täysin polaroituna.
Työn viimeinen osuus esittelee optisen laitteiston, jolla voidaan muokata pulssien aikaprofiilia. Laitteisto perustuu peräjälkeen aseteltuihin dispersiivisiin optisiin elementteihin ja aikariippuviin vaihesuotimiin, jotka yhdessä muodostavat aika-avaruuden analogian paikka-avaruudessa toimivasta optisesta kuvantamisjärjestelmästä. Pulssin polarisaatioominaisuuksia voidaan muokata moninaisilla tavoilla kohdistamalla pulssin keskenään kohtisuoriin polarisaatiokomponentteihin toisistaan eroavat aikasuurennokset.Polarization of light beams exhibits rich mathematical structure and great variety of applications in diverse areas, such as near-field optics, light-matter-interaction and optical communications. The polarization of light beams has been studied extensively for random, statistically stationary beams, but so far no consistent formalism has been introduced for characterizing partial polarization of pulsed beams.
The polarization formalism for stationary fields is presented in time and frequency domains in terms of the temporal polarization matrix and the cross-spectral density matrix, including some recent developments on the connection between temporal and spectral polarization. After recalling the theory for stationary fields, the main part of the thesis develops the polarization matrix formalism for non-stationary fields in both time and frequency domains. The connection between temporal and spectral polarization is derived and analyzed in terms of the measurable polarization quantities, the temporal and spectral degrees of polarization and the temporal and spectral Stokes parameters.
Examples are used to illustrate how the degree and state of polarization of a pulse may change with time or frequency. One of the examples describes a pulse whose temporal degree of polarization and polarization state may be tailored while keeping the pulse spectrally fully polarized.
The last part of the thesis presents an optical arrangement for modifying the temporal profile of pulses by using a cascade of dispersive optical elements and time-dependent phase filters, which forms the temporal analogy of a spatial imaging system. The polarization properties of a pulse may be adjusted in versatile ways by applying different temporal magnification to the pulse's orthogonal polarization components
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
From Poverty Economics to Global Social Policy A Sociology of Aid for Poverty Reduction
Full text linkPartial polarization and coherence in stationary and nonstationary electromagnetic fields
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