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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
Steamflood production mechanism in an edge pattern Duri field, Indonesia
No full textDue to the character of the original source materials and the nature of batch digitization, quality control issues may be present in this document. Please report any quality issues you encounter to [email protected], referencing the URI of the item.Includes bibliographical references (leaves 53-56).Issued also on microfiche from Lange Micrographics.The Duri field, located in Riau Province in Central Sumatra, Indonesia, is currently the site of the largest steamflood project in the world. Roughly half of the field is being flooded in eight project areas. Low oil rate has been encountered in the edge pattern in Duri field. The source of the problem is believed to be the poor steamflood efficiency due to water coning and steam possibly injected into water zone. Evidences for poor steamflood efficiency are a high Steam-oil Ratio and low wellhead temperature. A reservoir simulation study was performed to model the production mechanism in a typical edge pattern of Duri field. A history-match model was developed using a three- dimensional, black-oil, thermal reservoir simulator. A simple pattern-element, layer-cake model was used. Reservoir properties, except permeability and porosity, from the previous model were used and an excellent match of six years of historical performance was obtained by making minor changes in the water relative permeability data. From the result, it can be explained that there are two mechanisms happening to the steam flow in the reservoir. Gravity segregation tends to move steam upward, and least-resistance-flow-path (LRFP) tends to move steam downward due to water cone formed by the producers. LRFP is dominant in the beginning of the steamflood. Water temperature is lower than that of steam, causing even more flow downward to the water zone. Once temperature equilibrium is reached in the OWC, gravity override starts to take over the role. A horizontal well seems to be a good choice to improve the sweep efficiency, because of better contact between wellborn and pay-zone, resulting in lower pressure drawdown for the same production rate. Sensitivity analysis shows the best horizontal section is perpendicular to the reservoir dip. An experimental design using two-level factorial design was performed to find out what variables are influencing the cumulative production, discounted cumulative production and project life for drilling horizontal well in the situation as in Duri field. Correlations to estimate those quantities were developed using linear regression method. It is no surprise that the oil volume and discount factor are the variables that determine those quantities
Variations 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
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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