1,721,067 research outputs found
Subband neural networks for noisy signal forecasting and missing data reconstruction
No full textA subband multirate architecture is presented for data signal prediction and reconstruction. The architecture is based on a uniform filter bank that divides the input signal into many narrow band signals each of them predictable using a low order neural network. The main advantage of this approach consists in the extension of the forecast horizon using a low complexity network. In the case of missing data, this approach allows the reconstruction of a long data sequence from forward-backward predicted samples. Due to the multirate processing the subband networks input consists of a decimated version of the input signal. It follows a great reduction of the convergence time. Moreover, in presence of additive input noise, we can observe an improvement of the generalization performances. The experimental tests, conducted using noisy artificial nonlinear chaotic series, show a comparison between fullband and 4-channels subbands approaches involved in prediction and reconstruction tasks
On the convergence of steepest descent methods for multiobjective optimization
Full text linkIn this paper we consider the classical unconstrained nonlinear multiobjective optimization problem. For such a problem, it is particularly interesting to compute as many points as possible in an effort to approximate the so-called Pareto front. Consequently, to solve the problem we define an “a posteriori” algorithm whose generic iterate is represented by a set of points rather than by a single one. The proposed algorithm takes advantage of a linesearch with extrapolation along steepest descent directions with respect to (possibly not all of) the objective functions. The sequence of sets of points produced by the algorithm defines a set of “linked” sequences of points. We show that each linked sequence admits at least one limit point (not necessarily distinct from those obtained by other sequences) and that every limit point is Pareto-stationary. We also report numerical results on a collection of multiobjective problems that show efficiency of the proposed approach over more classical ones
Branchio-oto (BO) syndrome and oculo-auriculo-vertebral phenotype: overlapping clinical findings in a child from a BO family.
Full text linkA three-generation BO family is presented: the proband showed, in addition to branchio-oto malformations, a severe condition with growth retardation, mandibular hypoplasia and vertebral anomalies resembling the oculo-auriculovertebral (OAV) phenotype. This family study supports the hypothesis of Rollnick and Kaye that the OAV spectrum may represent, in some cases, an extreme component of the BOR syndrome. The finding has relevant implications for genetic counselling regarding both conditions
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
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
Survey of Italian pediatricians on awareness, experiences and beliefs regarding direct-to-consumer genetic testing in minors
Full text linkBackground: Our study wanted to assess Italian pediatricians’ awareness, experience and beliefs regarding directto- consumer (DTC) genetic tests (GT) in minors, with a focus on those for predisposition to complex disease, lyfestyle, athletic ability and other inborn talents. Methods: A 28-item questionnaire was administered through the SurveyMonkey® web platform to the 9,086 members of the Italian Society of Pediatrics for which a valid email address was available. The survey was opened from April through November 2017. Statistical analyses were performed using the Graphpad software package. Results: 36.2% of the 442 respondents were aware of DTC-GT, but only 23.1% of them felt adequately prepared to meet families’ information needs. The first three sources of knowledge were the Internet (20.98%), magazines/ newspapers (16.78%) and TV/Radio (14.33%), while companies’ direct marketing activity influenced knowledge only in 2.45% of the cases. Only 16.4% of the aware respondents had been already approached for advice. More than 95% of the pediatricians who were aware would not advise DTC-GT for lifestyle, athletic performance or other inborn skills. 69.2% was unfavourable to susceptibility tests for complex diseases. Most of them expressed an interest in learning more and indicated as preferred sources of information public policies issued by professional societies. Conclusion: The low awareness and experience and the vendors’ tiny contribution to knowledge suggest a still limited penetration of DTC-GT companies in Italy. A great interest in learning more was found. Scientific societies are best positioned to support health professionals in this educational goal thanks to their role of trusted sources of information and guidance
A concave optimization-based approach for sparse multiobjective programming
No full textThe paper is concerned with multiobjective sparse optimization problems, i.e. the problem of simultaneously optimizing several objective functions and where one of these functions is the number of the non-zero components (or the l-norm) of the solution. We propose to deal with the l-norm by means of concave approximations depending on a smoothing parameter. We state some equivalence results between the original nonsmooth problem and the smooth approximated problem. We are thus able to define an algorithm aimed to find sparse solutions and based on the steepest descent framework for smooth multiobjective optimization. The numerical results obtained on a classical application in portfolio selection and comparison with existing codes show the effectiveness of the proposed approach
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe 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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