1,721,231 research outputs found
Performance Limitation of Subband Adaptive Equalisers
Get PDFThe aim of this reported work was identifying and quantifying limitation for the subband adaptive equalisers. The derived Wiener solution is compared against simulations for the subband equaliser, and it is verified that aliasing caused in the subband decimation can be considered equivalent to channel noise. Finally, how this limitation can be mitigated by careful system design is discussed
Blind Multi-User Equalisation for a Dispersive DS-CDMA Downlink under Carrier Frequency Offset Conditions
No full textWe address blind multiuser detection in a DS-CDMA downlink channel in the presence of carrier frequency offset. The synchronous users are separated by re-establishing orthogonality of their spreading sequences in a shared equaliser at the chip level. The adaptation algorithm is based on a constant modulus criterion of the various users, for which a stochastic gradient descent algorithm can be derived. We show that the resulting filtered-error filtered-regressor algorithm requires modifications in order to cope with carrier offset, and propose an combined blind multiuser equaliser with blind carrier frequency offset estimation. Simulations demonstrating the algorithm's convergence and BER performance are presented
MMSE Limitations of Subband Adaptive Equalisers
No full textIn this contribution, we investigate limitations of the minimum mean square error (MMSE) solution for subband adaptive equalisers due to aliasing and error in power complementarity. By deriving the Wiener solution for the subband equaliser and comparing it against simulations, we verify that aliasing caused in the subband decimation can be considered equivalent to channel noise. We discuss how these limitations can be mitigated by careful system design
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
Virtual screening for PPAR-gamma ligands using the ISOAK molecular graph kernel and gaussian processes
No full textFor a virtual screening study, we introduce a combination of machine learning techniques, employing a graph kernel, Gaussian process regression and clustered cross-validation. The aim was to find ligands of peroxisome-proliferator activated receptor gamma (PPAR-y). The receptors in the PPAR family belong to the steroid-thyroid-retinoid superfamily of nuclear receptors and act as transcription factors. They play a role in the regulation of lipid and glucose metabolism in vertebrates and are linked to various human processes and diseases. For this study, we used a dataset of 176 PPAR-y agonists published by Ruecker et al. ..
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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