1,721,115 research outputs found
National Professor S K Mitra (FRS) and his disciples
Get PDF560-566This paper is a rapid survey of the multitude of events that covered the life and time of National Professor S K Mitra. It highlights the main activities of Prof. Mitra and his disciples for four decades since 1923. The survey has recorded significant events for the following four periods of time: 1923-39, 1939-45, 1945-49 and 1949-63. The step by step growth of research activities from a humble beginning in the small “Wireless Laboratory” of the University College of Science, Calcutta in 1923, to an internationally recognized centre for Advanced Studies in Radio Physics and Electronics in 1963, has been reported in this paper. The paper also emphasized as to how teamwork was strengthened through compilation of the various chapters of Prof. Mitra’s world-renowned treatise on Upper Atmosphere. The paper contains names of those disciples of Prof. Mitra who have earned international recognition in various fields of Radio Physics, Electronics and Space Science
Objective video quality metric based on data hiding
No full textIn this paper, a new no-reference (NR) objective metric based on data hiding is proposed. The metric has the advantage of being fast and not requiring knowledge of the original video contents. The proposed method uses a spread-spectrum embedding algorithm to embed a mark (binary image) into video frames. A t the receiver, the mark is extracted and a measure of its degradation is used to estimate the quality of the video. We used data gathered from psychophysical experiments to help in the design of the video quality assessment system. We evaluated the visibility and annoyance of the impairments caused by the embedding algorithm and estimated the 'best' mark strength for a particular video. The performance of the proposed metric is estimated by measuring its ability to predict the total squared error (TSE) of the host video and the mean observer score (MOS) obtained from naive subjects in a psychophysical experiment. Experimental results show that the proposed metric had a good performance and a good correlation with the MOS
Nonlinear Unsharp Masking Methods for Image Contrast Enhancement
No full textIn the unsharp masking approach for image enhancement, a fraction of the highpass filtered version of the image is added to the original image to form the enhanced version. The method is simple, but it suffers from two serious drawbacks. First, it enhances the contrast in the darker areas perceptually much more strongly than that in the lighter areas. Second, it enhances the noise and/or digitization effects, particularly in the darker regions, resulting in visually less pleasing enhanced images. In general, noise can be suppressed with lowpass filters, which are associated with the blurring of the edges. On the other hand, contrast can be enhanced with highpass filters, which are associated with noise amplification. A reasonable solution, therefore, is to use suitable nonlinear filters which combine the features of both highpass and lowpass filters. This paper outlines several new methods of unsharp masking based on the use of such nonlinear filters. Computer simulations have verified the superior results obtained using these filters. In addition, a new measure of contrast enhancement is introduced which quantitatively supports the improvement obtained using the proposed methods
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
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