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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
Yi zhong li bo kui tan ji duan wu li
No full textM.Phil.Recent detections of gravitational waves from binary black hole coalescences and binary neutron star coalescence give us opportunities to test general relativity in the strong field regime and constrain the nuclear equation of state of the neutron stars.By observing the gravitational waves from binary black hole mergers provide us with the opportunity of testing general relativity in the strong field regime. Evidence of deviation from general relativity can be investigated via comparing the incoming gravitational-wave signal to phenomenological general relativity waveform models including parameterized deviations from general relativity, or additional parameters absent in general relativity. However, the underlying general relativity model that is currently considered does not include all the physics present in general relativity. In particular, it considers only the ` = 2 modes of the gravitational-wave emission omitting the subdominant higher order modes. These have however a strong imprint on the gravitational-wave signal for the case of high mass, highly asymmetric and highly inclined binaries. This imprint might be mimicked by a suitable combination of the parameters deviate from general relativity, leading to fake apparent violations of general relativity. In this work, we perform a systematic study of these false violations across the parameter space of non-spinning binaries.A compact binary with the presence of a neutron star can help us constrain the equation of state of ultradense matter. The feasibility of constraining the equation of state through gravitational waves detections have typically been studied using the inspiral and post-merger stages separately. We quantify the benefits of combining the inspiral and the post-merger stages’ information when analysing binary neutron star signals. Moreover, we show that one can constrain the equation of state by probing at what mass the merged object remains in an extended hyper-massive neutron star phase or promptly collapses into a black hole.Unlike compact binary coalescences, core-collapse supernova or other gravitational-wave bursts cannot be searched with templates due to the complexity of the system. We present a Bayesian null stream method targeted for this kind of signals. We quantify the performance of this method on searching gravitational-wave signal and differentiating it from noise and glitches. Furthermore, we demonstrated the feasibility of testing gravitational-wave polarization with this method.最近對來自雙黑洞和雙中子星合併的重力波的觀測為我們提供了在強場區域中測試廣義相對論和約束中子星核狀態方程的機會。通過觀察來自雙黑洞的重力波，聚結了為我們提供在強場區域中測試廣義相對論的機會。通過比較數據中的重力波信號與現象學廣義相對論波形模型（包括與廣義相對論的參數化偏差或廣義相對論中不存在的附加參數），可以研究偏離廣義相對論的證據。然而，目前考慮的基礎廣義相對論模型並不包括廣義相對論中存在的所有物理。特別是，它只考慮重力波發射的` = 2 模式，省略了次優勢的高階模式。然而，對於高質量，高度不對稱和高度傾斜的雙星合併，這些次優勢的高階模式對於重力波信號具有強烈的印記。這種印記可以通過偏離廣義相對論的參數的適當組合來模仿，從而導致到虛假違反廣義相對論的觀測。在這項工作中，我們對非旋雙黑洞的參數空間中的這些虛假違反進行了系統研究。具有中子星存在的致密雙星系統可以幫助我們約束超密度物質的狀態方程。通過重力波探測來約束狀態方程的可行性通常分別使用螺旋階段和合併後階段進行研究。在分析雙中子星信號時，我們量化了合併螺旋階段和合併後階段信息的好處。此外，我們證明了人們可以通過探測合併後的星體在什麼質量會成為超大質量中子星相或者迅速坍縮成黑洞來約束狀態方程。與雙星合併不同，由於系統的複雜性，無法使用模板搜索核心崩潰超新星或其他重力波爆發。我們提出了針對這種信號的貝葉斯空流方法。我們量化了該方法在搜索重力波信號並將其與噪聲和毛刺區分開時的性能。此外，我們證明了用這種方法測試重力波極性的可行性。Pang, Tsun Ho = 以重力波窺探極端物理 / 彭浚豪.Thesis M.Phil. Chinese University of Hong Kong 2018.Includes bibliographical references (leaves 62-68).Abstracts also in Chinese.Title from PDF title page (viewed on …).Pang, Tsun Ho = Yi zhong li bo kui tan ji duan wu li / Peng Xunhao
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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