1,720,954 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
Deblending of seismic data
No full textSeismic imaging is one of the most common geophysical techniques for hydrocarbon exploration. Seismic acquisition is a trade-off between economy and quality. In conventional acquisition, the time intervals between successively firing sources are large enough to avoid interference in time. To obtain an efficient survey, the spatial source sampling is often (too) large, which results in spatial source aliasing. Simultaneous or blended acquisition was proposed by Beasley et al. (1998) and Berkhout (2008) in order to address this issue. In blended acquisition, temporal overlap between shot records is allowed. This additional degree of freedom in survey design has the potential to significantly reduce seismic acquisition costs while maintaining or even improving the data quality. Incoherent shooting plays a major role in the blended acquisition. It aims at preserving the energy distribution over the entire data bandwidth. There are several parameters that have to be considered in blended acquisition. Source encoding, lateral source configuration, blending factor, and survey condition are the most important parameters to be taken into account. These parameters are closely related and should not be considered irrespectively of each other. The acquired blended data can be processed in two ways: direct imaging and deblending. Deblending, which is the main focus of this thesis, is the procedure of retrieving the data as if they were acquired in the conventional, unblended way. After deblending the conventional, standard processing flows can be applied in practice. Since deblending is an underdetermined problem, a unique solution can not be achieved by matrix inversion. A least-squares solution could be used instead. However, the least-squares solution does not remove the interference due to other sources, called the blending noise. Fortunately, the character of the blending noise is different in different domains, i.e., it is coherent in the common source domain, but incoherent in the common receiver, common offset, and common midpoint domains. At the same time, the signal remains coherent in all domains. The incoherent character of the blending noise is directly related to the blended acquisition design. The coherence of the signal and the incoherence of the blending noise are the key properties that are used for deblending. In this thesis, an iterative inversion method is proposed for deblending, which is based on estimation and subtraction of the blending noise. In this method, the blending noise is modelled from the estimated signal and subtracted in an iterative fashion. The signal estimate is achieved by a process called coherencepass filtering, which consists of a filter in some domain followed by a thresholding step. At each iteration, the threshold is lowered and more of the blending noise is estimated and subsequently removed. Any type of filter that is capable of distinguishing between coherent signal and incoherent blending noise can be utilized in the coherence-pass filtering process. Three implementations of a coherence-pass filter, namely a median filter, an f-k filter, and a combined median-f-k filter are discussed. Among these, the combined median-f-k filter is a better choice due to the fact that it combines the median filter power in detecting blending noise with the f-k filter power in preserving the signal amplitude. The deblending process can be implemented in different data domains. The domain that is selected for deblending depends to a great extent on the blended acquisition design, acquisition geometry, and data properties. The algorithmic aspects of the deblending algorithm that are discussed in this thesis are related to the threshold automation, stopping criterion, filter edge artefacts, and signal estimation errors. The automation of the thresholding process that is based on the filter impact on the blending noise amplitude reduction, leads to a hands-off algorithm for deblending, optimized both for efficiency and effectiveness. The stopping criterion is based on a least-squares measure that is computed after each iteration. The deblending process is stopped when the measure reaches a stable state where no or negligible improvement is achieved. Furthermore, it is shown that one of the major limiting factors is related to edge artefacts generated by the filter. The blending noise that is estimated by the coherence-pass filtering is called the signal estimation error and is mainly caused by constructive or destructive interference of the blending noise with the signal. The effect of the signal estimation errors is evaluated by introducing errors in the coherence-pass filtering process. The result of this analysis shows that these signal estimation errors can be handled properly. The addressed practical considerations are mainly coherence and noise related issues. The incoherence in the signal is mainly caused by the irregularities in the acquisition geometry, near surface complexities, and topographic variations. Since coherence of the signal plays an essential role in deblending, the incoherence in the signal must be minimized prior to deblending. On the other hand, some of the noise-related issues can be handled during deblending. Proper handling of the practical issues is key to the success of the deblending process. The feasibility of the deblending algorithm is studied by applying it to three conventionally acquired datasets that are blended numerically. In the first example, 2D marine data are blended using upsweep and downsweep signals as source codes. Due to the favourable sophisticated source encoding, the deblending process can be performed per blended shot record using thresholding only, i.e., without blending noise filtering. In the second example, 2D land data are blended by time delays as source codes. In this case, the deblending process is performed in the common offset domain. Results are shown both for the data and their stack. In the last example, 3D land data are blended using two different blending configurations and their deblending results are compared. In this case the deblending process in performed in the common receiver domain. Overall, the obtained results are considered very promising.Geoscience & EngineeringCivil Engineering and Geoscience
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
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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