1,720,958 research outputs found
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
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
Time-lapse inversion of Controlled Source Electromagnetics using vertical sources and receivers
Get PDFKnowledge of spatial and temporal distribution of fluids in the subsurface is crucial
in a wide range of applications. During the production of crude oil typically high saline
produced formation water is injected into the reservoir layer, aiming to push the
oil towards production wells. While oil is commonly seen as an electrical insulator,
the injected saline brines are characterised by low electrical resistivity. Thus, electromagnetic
(EM) methods and especially Controlled Source Electromagnetics (CSEM)
attracted an increasing interest to monitor these resistivity changes inside the reservoir
over time.
This thesis mainly reports on numerical aspects of modelling and inversion of land
based CSEM with particular focus towards hydrocarbon monitoring applications.
Most of the presented developments were inspired by a superordinate research project
including CSEM field surveys across an actively producing onshore oil field in
Northern Germany.
In producing oil fields there exists a large number of steel-cased wells. Such existing
oil field infrastructure and especially the presence of metal casings significantly alters
the propagation of EM fields in the subsurface. Their spatially unfavourable dimensions
effectively prohibits a straightforward implementation into the modelling grid.
Thus I developed a new modelling approach allowing consideration of such thin but
vertically extended highly conductive structures including their mutual interaction.
The developed methodology had been implemented into existing modelling and inversion
codes. Using the new approach to investigate the influence of metal casings
on CSEM data shows that they act as additional inductively coupled vertical electric
dipole sources at depth and thereby increase resolution capabilities at depth. The
presence of metal casings can thus be exploited by optimising the source receiver
layout in such a way that the strength of these additional vertical dipole sources is
maximised.
An additional working package of the superordinate project was the measurement of
vertical electric fields in a shallow observation well. However, measurements of vertical
electric fields requires long measurement dipoles to achieve satisfactory signalto-
noise ratios. Such extended dipoles span several modelling cells and are therefore
in conflict with assumptions usually made for modelling, that receivers can be represented
as point dipoles. I therefore expanded the modelling and inversion codes
to consider the physical receiver dimensions. The new algorithm implicitly considers
imperfect alignment of the receiver with the corresponding field component. Without
the consideration of this effect inversion of vertical electric field measurements is
likely to cause erroneous results.
Finally I discuss different aspects of time-lapse inversion required to track changes in
fluid saturation over time. The cascaded inversion scheme is applied to synthetic timelapse
data for a simplified oilfield undergoing brine flushing. The influence of various
inversion parameters in particular different regularisation techniques are examined.
Surface based sources and receivers typically provide low sensitivity towards deep
targets in highly conductive backgrounds. Despite that using additional constraints,
in particular a model weighting scheme together with energised steel casings allowed
to track resistivity changes inside the reservoir based on synthetic time-lapse data.Wissen über räumliche und zeitliche Verteilung von Fluiden im Untergrund is unerlässlich
für eine Reihe von Anwendungen. Typischerweise wird während der Förderung
von Rohöl salinares produziertes Formationswasser in die ölführende Formation
injiziert um das Öl-Wasser-Gemisch in Richtung der Förderbohrungen zu spülen.
Während Öl als elektrischer Isolator gilt, zeichnen sich die injizierten salinaren Fluide
durch eine hohe elektrische Leitfähigkeit aus. Daher erfahren elektromagnetische
Methoden und insbesondere Controlled Source Electromagentics (CSEM) zunehmendes
Interesse diese Änderung des elektrischen Widerstands mit der Zeit zu
überwachen.
Diese Arbeit beschäftigt sich im wesentlichen mit numerischen Aspekten der Modellierung
und Inversion von CSEM an Land mit speziellem Fokus auf der Überwachung
der Kohlenwasserstoff Produktion. Die meisten der gezeigten Entwicklungen
sind entwickelt im Zuge eines übergeordneten Forschungsprojektes inklusive
CSEM Feldmessungen in einem produzierenden Ölfeld in Norddeutschland.
Produzierende Ölfelder sind gekennzeichnet durch eine große Anzahl von Stahl verrohrten
Bohrungen. Die Anwesenheit von Stahlinfrastruktur insbesondere von Stahlschutzrohren
beeinflusst die Ausbreitung von elektromagnetischen Feldern im Untergrund.
Deren unvorteilhafte Geometrie erlaubt keine direkte Berücksichtigung in
dem Modellierungsgitter. Daher habe ich einen neuen Modellierungsanzatz entwickelt
der es erlaubt solch dünne aber vertikal ausgedehnte hochgradig leitfähige Strukturen
inklusive deren gegenseitige Wechselwirkung zu berücksichtigen. Die entwickelte
Methode wurde in bestehende Modellierungs- und Inversionssoftware implementiert.
Mithilfe dieses neuen Ansatzes konnte der Einfluss von Stahlverrohrungen auf
CSEM Daten untersucht werden. Stahlverrohrungen wirken wie zusätzliche induktiv
angeregte vertikale elektrische Dipolquellen im Untergrund und helfen daher die Auflösung
in der Tiefe zu erhöhen. Die Anwesenheit von Stahlverrohrungen kann daher
ausgenutzt werden in dem man die Quell-Empfänger-Geometrie in einer Art und
Weise optimiert, die die Stärke dieser zusätzlichen vertikalen Dipolquellen maximiert.
Ein weiteres Arbeitspaket des übergeordneten Forschungsprojektes bestand in der
Messung von vertikalen elektrischen Feldern in flachen Beobachtungsbohrungen. Messungen
des vertikalen elektrischen Feldes erfordert lange Messdipole um ein ausreichendes
Signal-Rausch-Verhältnisses zu gewährleisten. Solch ausgedehnte Dipole
überspannen mehrere Zellen des Modellierungsgitters und verletzen die übliche Annahme,
wonach die Länge der Empfänger vernachlässigbar ist. Daher habe ich die
bestehenden Modellierungs- und Inversionsprogramme erweitert um die physischen
Dimensionen von elektrischen Feld Empfängern zu berücksichtigen. Der implementierte
Algorithmus berücksichtigt implizit Abweichungen der Orientierung des Messdipols
von der Richtung der zu messenden Feldkomponente. Ohne dieser Berücksichtigung
führt eine Inversion von vertikalen elektrischen Feld Daten zu fehlerhaften
Ergebnissen.
Schließlich werden unterschiedliche Aspekte von time-lapse Inversion diskutiert, welche
notwendig ist um Änderungen der Fluidzusammensetzung abzubilden und zu verfolgen.
Eine kaskadiertes Inversionsschema wurde auf synthetische time-lapse Daten
eines vereinfachten Ölfeldes angewendet. Untersucht wurde der Einfluss verschiedener
Parameter insbesondere verschiedener Regularisierungstechniken. Sender und Empfänger
an der Erdoberfläche sind typischerweise wenig sensitiv zu tiefen Strukturen
in leitfähiger Umgebung. Anhand von synthetische Daten konnte gezeigt werden,
dass das benutzen zusätzlicher Nebenbedingungen wie einer Modellgewichtung und
dem ausnutzen von vorhandenen Stahlverrohrungen es dennoch erlaubt Änderungen
innerhalb des Ölreservoirs zu lokalisieren
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
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
Author Under Sail The Imagination of Jack London, 1893-1902
No full textIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Intro -- Title Page -- Copyright Page -- Dedication -- Contents -- Acknowledgments -- Introduction -- 1. Spirit Truth -- 2. From Absorption to Theatricality and Back Again -- 3. "I Will Build a New Present" -- 4. Sons as Authors -- 5. Fathers as Publishers -- 6. The Daughter as Author -- 7. Lovers as Authors -- 8. At Sea with the Family -- 9. Yellow News, Yellow Stories -- 10. The Return Home -- Notes -- Bibliography -- Index -- About Jay WilliamsIn Author Under Sail, Jay Williams offers the first complete literary biography of Jack London as a professional writer engaged in the labor of writing. It examines the authorial imagination in London's work, the use of imagination in both his fiction and nonfiction, and the ways he defined imagination in the creative process in his business dealings with his publishers, editors, and agents. In this first volume of a two-volume biography, Williams traverses the years 1893 to 1902, from London's "Story of a Typhoon" to The People of the Abyss. The Jack London who emerges in the pages of Author Under Sail is a writer whose partnership with publishers, most notably his productive alliance with George Brett of Macmillan, was one of the most formative in American literary history. London pioneered many author models during the heyday of realism and naturalism, blurring the boundaries of these popular genres by focusing on absorption and theatricality and the representation of the seen and unseen. London created an impassioned, sincere, and extremely personal realism unlike that of other American writers of the time. Author Under Sail is a literary tour de force that reveals the full range of London as writer, creative citizen, and entrepreneur at the same time it sheds light on the maverick side of machine-age literature.Description based on publisher supplied metadata and other sources.Electronic reproduction. Ann Arbor, Michigan : ProQuest Ebook Central, YYYY. Available via World Wide Web. Access may be limited to ProQuest Ebook Central affiliated libraries
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