1,720,956 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
Optimal sizing and location on energy storage systems
Full text linkEnergy storage systems (ESSs) play an important role in the rate of renewable energy adoption. Because, in addition to their higher costs, renewable energy sources are also disadvantaged due to their highly variable and intermittent nature. Therefore, it is almost impossible to adopt renewable energy at a meaningful level without a well placed ESS infrastructure. Unfortunately, ESSs too may be quite expensive, which makes these infrastructure decisions even more important. Due to its popular nature, one might mistakenly believe that these ESSs are nothing but battery energy storage systems (BESS) placed at the sites of the renewable generation units. However, the most economical ESSs are those of pumped hydro storage (PHS) units that are dispersed across the geographies that are served by large electricity networks. The subject of this dissertation is to study siting and capacity decisions of ESSs in electricity transmission networks. We consider systems where electricity generation units from renewable and conventional sources are already established. For such systems our purpose is to find the location and capacities of ESSs and transmission line capacities to minimize the total system costs. Perhaps the greatest challenge in finding optimal solutions of these set of structural decisions is the incorporation of operational decisions which influence as well as are influenced by these structural decisions. In fact, optimal resolution of operational decisions alone is a daunting task even in the smallest networks because these decisions must be dynamically made while considering the uncertainties in electricity demand and supply. Therefore, we are compelled to adopt a sample average approximation (SAA) approach in the incorporation of those operational decisions. This dissertation has four main chapters. The introduction, apart from the overall motivation for this study, also presents a review of current technological and economical properties of wide variety of ESS alternatives. This section allows us to identify appropriate ESS alternatives that can be used in our models and their realistic cost estimates. The second chapter presents our problem in an island electricity system, which is commonly studied in energy literature for their simple transmission networks and small size. In our island system, there is only one generation unit, which is a wind farm, one demand node, and two alternative storage systems; one PHS with a known location and one BESS to be located at the site of the wind farm. Whenever there is a shortage, the demand is satisfied from diesel at the demand node. Hence, the structural decisions to be found are the capacities of ESSs and the transmission lines to minimize the total cost of investments, operations and maintenance, and diesel costs. We must also remark that capacity of an ESS is a pair of variables; one for the maximum energy storage and one for the maximum energy flow, which are commonly referred as the energy rate and power rate, respectively. By deploying two different storage types at different places, we investigate the circumstances where installation decisions change. Stochastic renewable energy generation and demand are taken into account by scenarios that are reproduced based on real data. The third chapter extends the mathematical model to a small grid system with 13 nodes that consist of various generation units and demand centers. Despite being far smaller than many realistic grid systems, the problem has shown to be far beyond resolution with the existing computational resources. Therefore, we have developed a two-stage algorithm, which determines the investment decisions in the first stage, followed by the second stage operational decisions. Finally, the fourth chapter revisits the island system with solar power instead of the wind power, to investigate how differences in the intermittent feature of the two most common renewable sources affect the optimal structural decisions
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
Joint optimization of energy storage sizing and transmission line capacities for an island system
No full textIn this work, we present a stochastic mixed-integer programming model to optimize the sizes of two different kinds of energy storage systems and the capacity of the transmission lines for an island system. We consider an island where the main generation source is wind and alternative source is diesel. The primary aim of this study is to investigate the investment decisions in storage and to determine energy capacities and power rates of the storage systems while minimizing the construction, O&M, and diesel costs. By deploying two different storage types at different places, we investigate the circumstances where installation decisions change. Stochastic renewable energy generation and demand are taken into account by considering different scenarios which are reproduced based on real data. First-order Markov chain is used to generate monthly wind power time series. Numerical experiments are conducted to investigate the effect of the cost parameters on the system design
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