1,721,134 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
Electricity markets under the influence of renewables: Modelling, prediction, and stochastic optimization
Full text linkIm Rahmen des Zubaus erneuerbarer Energieträger in Deutschland verändert sich der deutsche Energiemix, der sich aus den in Deutschland vorhandenen Stromquellen zusammensetzt. Mit dem Wandel hin zu nachhaltigen Stromquellen wie Wind- und Solarenergie verändert sich auch die Situation, der sich der Strommarkt gegenübersieht. Während in der Vergangenheit wenig Unwägbarkeiten in der Stromerzeugung existierten und nur die Nachfrage stochastische Unsicherheiten aufwies, ist mittlerweile aufgrund der Wetterabhängigkeit auch die Erzeugung stochastischen Schwankungen ausgesetzt. Um für diese andersartige Situation einen unterstützenden Rahmen zu bieten, wurden am Strommarkt unter anderem der Intradaymarkt, Produkte mit halb- und viertelstündigen Zeitscheiben und ein verändertes Regelenergiemarktdesign eingeführt. Damit sind sowohl die Themen der Strompreisvorhersage als auch die der Optimierung auf den Strommärkten weiterhin aktuell.
Diese Arbeit beschäftigt sich zunächst mit der Modellierung des Intraday-Markts und der Prognose von Intraday-Indices. Dafür bewegen wir uns auf die Ebene der einzelnen Gebote am Intraday-Markt und modellieren mit diesen die Limitorderbücher der Intraday-Produkte. Basierend auf ausgewählten statistischen Kenngrößen der modellierten Limitorderbücher stellen wir einen neuartigen Schätzer für die Intraday-Indices vor. Gerade für Produkte mit weniger Liquidität enthalten die Orderbuchstatistiken relevante Informationen, die signifikant genauere Vorhersagen als der Vergleichsschätzer ermöglichen.
Da der Day-Ahead-Markt im Gegensatz zum Intraday-Markt als Markt mit täglicher Auktion betrieben wird, bietet er kleineren Unternehmen ohne eigene Handelsabteilung die Möglichkeit, sich am Strommarkt zu beteiligen. Aus deren Perspektive optimieren wir ihr Flexibilitätsangebot am Day-Ahead-Markt und modellieren dabei die Preise mithilfe eines stochastischen Mehrfaktormodells, welches bereits Einsatz in der Industrie findet. Um dieses Modell für die stochastische Optimierung aufzubereiten, wird eine Diskretisierung des Modells in Zeit und Raum mithilfe von Szenariobäumen vorgenommen. Hier stellen wir sowohl vorhandene Algorithmen zur Szenariobaumerzeugung als auch unsere eigenen Erweiterungen und Anpassungen vor. Diese basieren auf der Nested Distance, welche den Abstand zweier Verteilungen stochastischer Prozesse misst. Auf Basis der so entstandenen Szenariobäume wenden wir schließlich die stochastischen Optimierungsmethoden der stochastischen Programmierung, der dynamischen Programmierung und des Reinforcement Learnings an und untersuchen, in welchem Kontext die Methodiken jeweils geeignet sind.The German energy mix, which provides an overview of the sources of electricity available in Germany, is changing as a result of the expansion of renewable energy sources. With this shift towards sustainable energy sources such as wind and solar power, the electricity market situation is also in flux. Whereas in the past there were few uncertainties in electricity generation and only demand was subject to stochastic uncertainties, generation is now subject to stochastic fluctuations as well, especially due to weather dependency. To provide a supportive framework for this different situation, the electricity market has introduced, among other things, the intraday market, products with half-hourly and quarter-hourly time slices, and a modified balancing energy market design. As a result, both electricity price forecasting and optimization issues remain topical.
In this thesis, we first address intraday market modeling and intraday index forecasting. To do so, we move to the level of individual bids in the intraday market and use them to model the limit order books of intraday products. Based on statistics of the modeled limit order books, we present a novel estimator for the intraday indices. Especially for less liquid products, the order book statistics contain relevant information that allows for significantly more accurate predictions in comparison to the benchmark estimator.
Unlike the intraday market, the day ahead market allows smaller companies without their own trading department to participate since it is operated as a market with daily auctions. We optimize the flexibility offer of such a small company in the day ahead market and model the prices with a stochastic multi-factor model already used in the industry. To make this model accessible for stochastic optimization, we discretize it in time and space using scenario trees. Here we present existing algorithms for scenario tree generation as well as our own extensions and adaptations. These are based on the nested distance, which measures the distance between two distributions of stochastic processes. Based on the resulting scenario trees, we apply the stochastic optimization methods of stochastic programming, dynamic programming, and reinforcement learning to illustrate in which context the methods are appropriate
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
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