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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
Studium elektrických a elektrochemických vlastností tenkovrstvých materiálů pro rozklad vody
No full textVariations 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
Studium elektrických a elektrochemických vlastností tenkovrstvých materiálů pro rozklad vody
No full textTato bakalářská práce se zabývá fotoelektrochemickým rozkladem vody a produkcí vodíku. Nejprve rozebírá fotokatalytický rozklad látek se zaměřením na vodu, včetně podmínek pro průběh chemických reakcí. Následně se zevrubně věnuje fotoelektrochemickému rozkladu vody jako kompromisu mezi fotokatalytickým a elektrolytickým procesem. Popsány jsou funkce potenciostatu včetně úloh pracovní a protielektrody a referenční elektrody, která má důležitou úlohu nejen při měření, ale i při diskuzi výsledků. Dále jsou uvedeny procesy ve fotoelektrochemické komoře při štěpení vody a nároky, které jsou kladeny na pracovní polovodičovou elektrodu, která je fotoaktivní a generuje volné nosiče náboje schopné redoxních dějů. Následuje metodika fotoelektrochemických experimentů a jejich vyhodnocení včetně výpočtů účinností.
Získané teoretické poznatky jsou následně aplikovány při zkoumání fotoelektrochemických vlastností tenké vrstvy Cu-W-O, která byla připravena reaktivní magnetronovou depozicí. Elipsometrickým měřením byla určena šířka zakázaného pásu, extinkční koeficient a absorpce vrstvy. Základní fotoelektrochemické vlastnosti vrstvy jako je polarita polovodiče, míra rekombinace a fotoaktivní zóna s malými temnostními proudy byly měřeny při osvitu intenzivní ultrafialovou lampou ( = 370 nm, P = 3,9 mW/2). Pokročilejší spektroskopická měření proběhla s využitím světelného zdroje J. A. Woollam HS-190. Změřeny byly fotoproudy pro vybrané vlnové délky a spočtena vnější kvantová efektivita (IPCE). Předpokládaný spočtený fotoproud při osvitu normovaným slunečním světlem AM1,5 je 1,38 A/m2. Fotoelektrochemické vlastnosti Cu-W-O jsou v této práci porovnávány s vlastnostmi tenké vrstvy materiálu WO3.ObhájenoThis bachelor thesis deals with photoelectrochemical water splitting and hydrogen production. First, it discusses the photocatalytic decomposition of substances with a focus on water, including the conditions for the course of chemical reactions. Subsequently, it deals in detail with the photoelectrochemical water splitting as a compromise between the photocatalytic and electrolytic processes. The functions of the potentiostat are described, including the tasks of the working and counter electrode and the reference electrode, which has an important role not only in the measurement but also in the discussion of the results. The following are the processes in the photoelectrochemical cell during the splitting of water and the demands that are placed on the working semiconductor electrode, which is photoactive and generates free charge carriers capable of redox processes. The methodology of photoelectrochemical experiments and their evaluation, including efficiency calculations, follows.
The obtained theoretical knowledge is then applied in the investigation of photoelectrochemical properties of a thin layer of Cu-W-O, which was prepared by reactive magnetron deposition. The width of the bandgap, the extinction coefficient, and the layer absorption were determined by ellipsometric measurements. The basic photoelectrochemical properties of the layer such as semiconductor polarity, recombination rate, and photoactive zone with small dark currents were measured under exposure to an intense ultraviolet lamp ( = 370 nm, P = 3.9 mW/2). More advanced spectroscopic measurements were performed using a J. A. Woollam HS-190 light source. Photocurrents for selected wavelengths were measured and external quantum efficiency (IPCE) was calculated. The assumed calculated photocurrent under exposure to standardized sunlight AM1.5 is 1,38 A m. In this work, the photoelectrochemical properties of Cu-W-O are compared with the properties of the thin layer of WO3 material
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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