1,721,102 research outputs found
High performance speaker verification system based on multilayer perceptrons and real-time enrollment
No full textSpeaker verification systems based on multilayer perceptrons (MLI's) have good prospects in reliability and flexibility as required for a successful authentication system. However, poor learning speed of error backpropagation (EBP), the representative method of learning for MLPs, has been the major problem which must be resolved to achieve real-time user enrollment. In this paper, we implement an MLP-based speaker verification system by applying methods of omitting patterns in instant learning (OIL) and discriminative cohort speakers (DCS) to approach the real-time enrollment. We evaluate the system on a Korean speech database and demonstrate the feasibility of it as a speaker verification system of high performance
Elastic learning rate on error backpropagation of online update
No full textThe error-backpropagation (EBP) algorithm for learning multilayer perceptrons (MLPs) is known to have good features of robustness and economical efficiency. However, the algorithm has difficulty in selecting an optimal constant learning rate and thus results in non-optimal learning speed and inflexible operation for working data. This paper introduces an elastic learning rate that guarantees convergence of learning and its local realization by online update of MLP parameters into the original EBP algorithm in order to complement the non-optimality. The results of experiments on a speaker verification system with Korean speech database are presented and discussed to demonstrate the performance improvement of the proposed method in terms of learning speed and flexibility for working data of the original EBP algorithm
Suspension of a field-cooled BiPbSrCaCuO high-T-c superconductor under a toroidal permanent magnet
No full textMagnetic flux measurements of a toroidal magnet revealed a concave-shaped field distribution with a single minimum and a null field along the axis of the torus at the point where the field reversed. The non-linear magnetic field of the toroidal magnet perpendicular to the Ag2O-doped superconducting disc sample with trapped magnetic flux distorted the field line distribution. As a result, the interaction force between the magnet and the sample exhibited regions of repulsive, null, attractive, null and finally repulsive force. The asymmetrical concave-shaped force pattern along the axis with two null force points indicates that the force exerted on the sample changes direction, the transition from repulsive to attractive at the null force point, and the force becomes repulsive again beyond the second null force point as the distance along the axis increases. The magnetic field simulation using the Poisson numerical code for the toroidal magnet of 46 mm OD, 12 mm ID and 10 mm thickness was in close agreement with the force measurements. The lateral stability of a suspended sample under the toroidal magnet is provided by the characteristic symmetrical nature of the field line with respect to the axis of the magnet. The concave-shaped magnetic field forms a vertical magnetic wall around a suspended superconducting sample as demonstrated with lead, a type 1 superconductor. Thus, the toroidal magnet with a concave-shaped magnetic field distribution with respect to the mid-plane of the magnet provides much improved lateral stability for the magnetic bearing. Furthermore, this arrangement provides a loss-free shielding current in the absence of viscous drag from the environment or eddy current or hysteresis. The magnetic moment of an undoped and 2% Ag2O-doped samples was shown to be m = 0.043 emu and 0.06 emu, respectively. The measured suspension force exerted on the doped sample agreed well with that calculated from the magnetostatic force distribution
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
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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