1,721,058 research outputs found

    Video-Analysis of Player's Kinematics in Running out of Boundaries in Association Football Fields

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    AbstractThe risk of injury following a player's impact with objects in sport facilities is a growing problem, as shown by serious accidents that happen when players have head impacts with obstacles and barriers installed around the play area. At present, no experimental data are available about the kinematics of football (soccer) players during a running-out of playing areas scenario. Experimental tests on a sample of 14 skilled football players, aged between 17 and 19 years, were conducted to investigate athletic performances in common gaming actions of running, considered potentially-damaging when they occur near the boundary lines of the regular pitch. In the current research, a player's motion was captured with a high-frequency camera and kinematic data were video-analysed. The experimental trials resulted in kinematic data plots, characterised by a decelerating trend of the speed versus the distance covered by the players during the required movements. A section at the starting point and three sections at consecutive distances (a total amount of four sections in correspondence of 0 m and consecutive 1.5 m, 2.5 m, 3.5 m on the lane covered by players) of the decelerating trends of data were analysed. Findings of this pilot study should be useful for the improvements of passive safety in sports fields, allowing the correlation of the potential impact energy of players with the installation distances of protective devices

    Going Beyond Counting First Authors in Author Co-citation Analysis

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    The 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

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    “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

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    We 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

    On Relevance, Time and Query Expansion

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    We present the results of our exploratory analysis on the relationship that exists between relevance and time. We observe how the amount of documents published in a given interval of time is related to the probability of relevance, and, using the time series analysis, we show the existence of a correlation between time and relevance. As an initial application of this analysis, we study query expansion exploiting the detection of publication time peaks over the Blog06 collection. We finally propose an effective approach for the query expansion in the blog search domain. Our approach is based on the documents publication trend being so completely independent of any external resource
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