1,720,960 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
On building blocks of finite volume methods : Limiter functions and Riemann solvers
No full textIn this thesis we are interested in numerically solving conservation laws with high-order finite volume methods. Hyperbolic systems of partial differential equations are especially challenging since even smooth initial flows may develop discontinuities in finite time. Naively discretizing such flows with high-order schemes may lead to undesired oscillations at discontinuities. First-order methods do not encounter this problem since shocks are smeared out. Nevertheless, high-order schemes are in demand because they have the advantage of reaching a fixed error bound on coarser grids than low-order methods. This reduces the overall computational time and thus the total cost. Combining the advantages of several methods, limiter functions change from high- to low-order whenever necessary. This avoids oscillations at discontinuities while maintaining high-order accuracy at smooth parts of the solution. Thus, the resulting schemes are applicable to physically relevant problems which often contain smooth parts as well as large gradients, discontinuities, or shocks. The aim of this work is the development of third-order finite volume methods by improving building blocks of the method. This means, we identify main routines in the finite volume framework and present new concepts for improving their performance. We focus on two building blocks. First, the high-order reconstruction of interface values using limiter functions. Second, the numerical flux function, also referred to as Riemann solver. The former is crucial for the order of accuracy of the solution while the latter determines the amount of dissipation added to the scheme. We develop a new third-order accurate reconstruction function for the spatial approximation of hyperbolic conservation laws. This reconstruction switches between first- and third-order, resulting in a scheme which is high-order accurate in smooth parts of the solution, does not create oscillations at discontinuities, and avoids extrema clipping as encountered by total variation diminishing (TVD) methods. The novel limiter only needs information from the cell of interest and its nearest neighbors, thus keeping the stencil as compact as possible for obtaining third order accuracy. Furthermore, the reconstruction remains in the traditional second-order framework, easing the implementation of the limiter in existing codes. Finally, a decision criterion without artificial parameters is incorporated in the limiter. This decision criterion distinguishes shocks and large gradients from extrema, thus ensuring accurate shock capturing. The obtained reconstructions at each side of the cell boundaries are then inserted into the numerical flux function which solves local Riemann problems. Many numerical flux functions, also referred to as Riemann solvers, have been developed over the last decades. However, most classical solvers add too much dissipation to the scheme such that discontinuities are smeared out. On the other side of the spectrum, Riemann solvers that do not add too much dissipation need information on the eigen structure which is costly to compute for large systems. There is the need for new Riemann solvers that avoid solving for the eigen system and still reproduce all waves of the system with less dissipation than classical methods such as Rusanov and Harten-Lax-van Leer (HLL). We present a hybrid family of Riemann solvers, requiring only an estimate of the globally fastest wave speeds in both directions. Thus, the new solvers are particularly efficient for large systems of conservation laws when no explicit expression for the eigen system is available or expensive to compute. For the validation of the developed schemes we conduct a series of numerical experiments. First, we demonstrate that the novel high-order limiter function obtains the desired third-order accuracy for smooth solutions. Test cases includes mooth and discontinuous linear transport, Euler equations, and ideal magneto hydrodynamics (MHD). Problems are presented in one and two space dimensions, on uniform as well as non-uniform grids and with adaptive mesh refinement. In a second step, the hybrid family of Riemann solvers is tested in a first-order framework. Here, we show that the newly developed solvers induce less dissipation than schemes with comparable input data. This leads to sharper gradients and less smearing at discontinuities. Numerical examples contain linear transport, Euler equations, ideal MHD, as well as the regularized 13-moment equations (R13).Finally, both parts of this work are combined to obtain third-order accurate results. We reconstruct using the novel third-order limiter and insert there constructed interface values into the hybrid family of Riemann solvers. For all numerical examples, we also implement comparable methods to ascertain the quality of our schemes. The solutions obtained with the newly developed methods indeed indicate better or equally-good results and an excellent performance
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
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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