1,721,205 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
A 260-MHz RF Bandwidth Mixer-First Receiver with Third-Order Current-Mode Filtering TIA
No full textA mixer-first wideband receiver with RF bandwidth of 260 MHz suitable for the 5G lower frequency band (below 6 GHz) is presented. The filtering trans-impedance amplifier immediately following the mixer is based on a regulated cascode, instead of a conventional shunt-feedback architecture. Thanks to a positive-feedback capacitance multiplication, third-order low-pass filtering in the current domain is performed. Wide bandwidth, high linearity, and low power are thus achieved. Measurements on a 28-nm CMOS chip prototype show alternate channel IIP3 and P1dB of +22 dBm and +3 dBm, respectively. RX NF is 5.5 dB while power consumption is 21.6 mW (signal path) and 7.8-mW/GHz (LO) with 1.8/1.2-V supply
Variations on the Author
Full text link“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
Full text linkWe 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
Accelerated simultaneous iterations for large finite element eigenproblems
No full textAn acceleratedsimultaneousiteration method is presented for the solution of the generalized eigenproblem Ax = λBx, where A and B are real sparse symmetric positive definite matrices. The approach is well suited for the determination of the leftmost eigenpairs of problems with large size N. The procedure relies on the optimization of the Rayleigh quotient over a subspace of orthogonal vectors by a conjugate gradient technique effectively preconditioned with the pointwise incomplete Cholesky factorization. The method is applied to the evaluation of the smallest 15 eigenpairs of finiteelement models with size ranging between 150 and 2300. The numerical experiments show that, while the simultaneous conjugate gradient scheme fails to converge, the acceleratediterations yield accurate results in a number of steps which is much smaller than N. The new approach does not require the a priori estimate of any empirical parameter and appears to be a robust, reliable, and efficient tool for the partial eigensolution of largefiniteelement problems
Solution to Large Symmetric Eigenproblems by an Accelerated Conjugate Gradient Technique
No full textThe computation of the smallest eigenvalues and eigenvectors of large numerical problems is a very important task in a number of engineering applications. The eigensolution to finite element or finite difference linear models provides the shape of the normal modes of vibration and the corresponding natural frequencies of mechanical, structural and hydrodynamical systems.
In the present paper the leftmost eigenpairs of large sparse symmetric positive definite matrices are assessed by an efficient numerical technique which combines a deflation procedure together with an optimization approach wherein the Rayleigh quotient is minimized by an accelerated conjugate gradient scheme. The acceleration is achieved by the aid of a preconditioning matrix given by the incomplete Cholesky factorization of the discretized model.
The results from finite element matrices show that the p (with p equal to 10÷15) smallest eigenvalues and eigenvectors are evaluated by the iterative deflating method after a number of iterations which turns out to be some orders of magnitude smaller than the problem size N. Several numerical experiments emphasize the promising features of the proposed approach
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