1,720,999 research outputs found
Exact Analysis of Different Detector Algorithms for NDA Carrier Phase Recovery of 16-APSK Signals
No full textIn the new digital video broadcasting standard for satellite communications (DVB-S2), 16-ary amplitude-phase shift keying (APSK) is recommended as modulation scheme. For carrier phase recovery with feedback loops, deci-sion-directed (DD) and non-data aided (NDA) detector algo-rithms are basically applicable to 16-APSK schemes as well. In a recent paper, however, a hybrid NDA/DD solution has been suggested although not analyzed in detail. Motivated by this fact, the latter is investigated in terms of detector characteris-tic (S-curve) and jitter variance as the main figures of merit in this respect. For comparison purposes, results for power-law and monomial-based Viterbi and Viterbi trackers, as classical NDA solutions, are also included
Extended Gardner Detector for Improved Symbol-Timing Recovery of M-PSK Signals
No full textIn a recent paper, the modified Gardner detector has
been proposed for advanced symbol-timing recovery of M-ary
phase-shift keying signals. Compared with the original algorithm,
the self-noise jitter can be considerably reduced for highly
bandlimited systems and smaller values of . In this letter, a
completely different approach is investigated, which improves the
self-noise performance for larger values of M, as well
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
Transmission Systems Exact analysis of different detector algorithms for NDA carrier phase recovery of 16/32-APSK signals
No full textIn the new digital video broadcasting standard for satellite communications (DVB-S2), 16- and 32-ary amplitude-phase shift keying (APSK) are recommended as complementary modulation schemes to 4-PSK and 8-PSK. For carrier phase recovery with feedback loops, decision-directed (DD) and non-data-aided (NDA) detector algorithms are basically applicable. In some recent papers, however, a hybrid NDA/DD solution has been suggested for this purpose, although not analysed in detail. Motivated by this observation, the hybrid algorithms are investigated in this paper in terms of detector characteristic (S-curve) and jitter variance as the main figures of merit in this respect, with an additional design parameter introduced for optimisation. For comparison reasons, results for power-law and monomial-based Viterbi and Viterbi (V & V) trackers, as classical NDA solutions, are derived as well
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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