1,721,144 research outputs found
Sensing strategies for channel discovery in Cognitive Radio Networks
No full textWe consider spectrum sensing strategies used to discover available spectrum in Cognitive Radio Networks (CRNs), using both non-cooperative sensing and cooperative sensing approaches. After introducing the background to sensing techniques, this position paper focuses on strategies and algorithms for conducting sensing such that the sensing time and energy are minimized, and the likelihood of finding available spectrum is maximized. The paper mainly focuses on two approaches. The first is the ordering of channels to be sensed, and the second is cooperative spectrum sensing. After discussing the available strategies under each of these two approaches, we introduce our own proposed approaches. We first introduce a method for sorting the channels to be sensed in order to optimize the sensing time, while satisfying PUs' protection and false alarm constraints. Then, we introduce a framework for cooperative sensing of multiple PUs' channels by a group of SUs. The framework includes strategies for assigning different SUs to sense different PUs' channels, selection of the fusion center for each of the SUs clusters, and routing sensing data within the cluster from the SUs to the fusion center. We show how this framework is capable of optimizing different objective functions. Several open problems and future research directions are also introduced.</p
Warfarin-induced calciphylaxis: a case report and review of literature
No full textChadi Saifan, Marc Saad, Elie El-Charabaty, Suzanne El-SayeghStaten Island University Hospital, Staten Island, NY, USAAbstract: Calciphylaxis is a challenging complication of end-stage renal disease, with an unknown underlying mechanism. Several risk factors have been identified, such as hyperphosphatemia, hypercalcemia, hyperparathyroidism, low serum albumin levels, and history of warfarin therapy. This article presents a case of calciphylaxis provoked by reintroduction of warfarin therapy, introducing the possibility of direct induction.Keywords: warfarin, calciphylaxis, skin necrosis, ESR
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
Three-probe reflectometer algorithm for calculation of complex reflection coefficient of liquids / Aidil Saifan Abu Bakar
Get PDFThis paper describes a technique for measurement of complex reflection coefficient of liquids using slotted line (implemented in waveguide form). In order to make precision measurement of magnitude and phase of reflection coefficient, the Three-Probe Reflectometer Algorithm has been used (which was implemented on the personal computer using Visual Basic 6 programming). The setup between hardware and software will provide a real-time measurement system of complex reflection coefficient. The measurement of magnitude and phase of reflection coefficient by the prototype instrument were compared with standard calculated values from Maple programming in order to find the correlation between them. The experimental tests have confirmed that the prototype instrument is able to yield measurement accuracies of within ±0.1 for magnitude and ± 5° for phase. By adding two more additional probes this prototype measurement system can be used as an automated instrument for measurement of dielectric properties of the material under test
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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