1,721,026 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
Strategies of geological modeling and scale-up in reservoir simulation.
No full textThe objective of this study was to study the improved vertical layering method for scale-up, to develop an effective scale-up methodology, and to investigate the effects of geological modeling strategies, well locations, and reservoir boundary conditions on the scale-up of petrophysical properties. The Gypsy formation was used as the experimental site in this study.The scale-up method developed in this study was applied for three Gypsy models. It was observed that the transmissibility scale-up is only suitable for linear flow. A scale-up on productivity index must be conducted to consider the effects of radial flow around wellbore in order to obtain a satisfactory scale-up result. Significant improvements were obtained after conducting a PI scale-up. Contrary to our expectation, channel model and lithofacies model resulted in similar scale-up results, but flow unit model resulted in large errors. Comparing the scale-up results for three different production scenarios and three different boundary conditions, it was observed that the proposed scaling process provided better results in scenario involving line-drive compared to the nine-spot and five-spot scenarios. The method also produced better scale-up results for system with no-flow boundary condition compared to bottom-water drive and edge-water drive.Three Gypsy models, channel model, lithofacies model, and flow unit model, were generated in this study. A methodology for scale-up was developed, in which transmissibility, instead of permeability, was scaled up. After a linear scale-up was conducted between the grid blocks, a scale-up on productivity index, or PI scale-up, was performed to consider the radial flow around the wellbore. Special considerations were given to the pinch-out grid blocks in the system in order to obtain a representative flow simulation. Two hypothetical models, a layer-cake model and a pinch-out model were used to illustrate the application of the methodology. Successful scale-up results were obtained after a PI scale-up technique around the wellbore was applied
Leak-off and cleanup behavior of fracturing fluids in the presence of mobile hydrocarbons.
Full text linkLeak-off characteristics in the presence of mobile gas or oil saturation are significantly different compared to those observed in the presence of 100% brine saturation. In the case of mobile gas saturation, the spurt loss appears to be driven by spontaneous imbibition, whereas the long-time leak-off is controlled by relative permeability effects. The wall building coefficients are at least an order of magnitude lower than those observed in 100% brine saturated core samples. The fluid loss additive used in this study appears to have little or no effect on leak-off. In the case of mobile oil saturation, both oil viscosity and relative permeability effects play a role in determining the leak-off response. The spurt loss is significantly lower than that observed in 100% brine saturated core samples. In this case also, the fluid loss additive has little or no effect on leak-off. The leak-off characteristics exhibit noticeable sensitivity to the formation permeability.A dimensionless correlation to determine the cumulative leak-off volume into the rock matrix during the dynamic filtration of a fracturing fluid is presented in the last section. The correlation is developed based on dimensional analysis. The model is validated using data obtained from dynamic leak-off experiments. (Abstract shortened by UMI.)Recovery of permeability in the presence of oil is higher compared with that in the presence of 100% brine saturated cores. The recovery, especially for linear and crosslinked hydroxypropyl guar (HPG), is greater than 100% of the original permeability and is dependent on shut-in time. The fluid loss additive does not appear to affect regain permeability. The production rate has a positive impact on regain permeability.The first part of this study presents the results of a series of laboratory experiments conducted to investigate the dynamic leak-off behavior of fracturing fluids in the presence of mobile gas or oil saturation. Fracturing fluid leak-off in low permeability gas saturated and high permeability oil saturated reservoir rocks is examined under conditions of varying fracturing fluid composition, formation permeability, oil composition, and fracturing pressure. The effectiveness of fluid loss additives in controlling the leak-off during multiphase flow near the fracture face is also investigated. In addition, a conceptual model to predict the leak-off in the presence of mobile gas or oil saturation at the fracture face has been developed. The model is validated using data obtained from dynamic leak-off experiments.In the second part of this study, the extent of impairment in formation permeability to oil due to the leak-off of fracturing fluid in oil reservoirs and subsequent recovery during production is evaluated and characterized. The experiments are conducted with a number of commonly used fracturing fluids. Effect of shut-in time, fluid loss additive, fracturing fluid composition, production rates, and oil composition on the regain permeability of oil reservoirs is investigated
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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