1,720,963 research outputs found
Larger-Than-Memory Stateful Stream Processing with WindFlow
No full textIn stream processing, a vast volume of data is continuously processed by standing queries that extract insights from raw inputs. These queries often maintain an internal state, representing useful information from the stream’s history, to produce results. Notable examples of state paradigms include sliding windows, where computation is periodically repeated over the most recent data (e.g., inputs received in the last ten seconds, sliding every half second). Additionally, this state is replicated per distinct key, a user-defined attribute used to partition the physical stream into logical sub-streams. The combination of numerous keys (often millions in real-world scenarios) and the window size can make the overall state of a streaming query enormous, potentially exceeding available memory. This issue is particularly critical when the processing is done on resource-constrained, low-end devices like in the Edge computing paradigm. In this paper, we focus on designing a family of persistent operators capable of transparently maintaining their internal state in an external Key-Value Store, thereby leveraging secondary memory. We present this design within the context of the WindFlow stream processing library for multi-core architectures. The paper details our design and implementation, along with an experimental evaluation based on a set of benchmarks, to assess the performance of persistent operators compared with traditional in-memory processing
Kinematic scheme of the push gesture in cross-country sit-skiers
No full textResults of the biomechanical analysis of the push gesture in paralympic cross-country sit-skiers on plane track of the competition field are presented
A Biomechanical Approach to Paralympic Cross-Country Sit-Ski Racing
No full textObjective: To analyze the biomechanics of the double poling gesture in cross country disable sit–skiers in the field during competition.
Design: Elite athletes were recorded during the 1 km sprint race with a high speed markerless stereo photogrammetric camera system. Reference points were semi-automatically tracked frame-by-frame on video images, according to a biomechanical model consisting of seven anatomical and four technical points. Coordinates of points were evaluated for 2D kinematic analysis of the push gesture both in a word and sledge reference frames.
Setting: Winter Paralympic Games, Vancouver 2010, Canada.
Subjects: Paralympic athletes: 35 men and 15 women; classified in all the five classes of the sit skiers category.
Results: Several graphical results represent the development of the double poling gesture of each athlete with respect to both world reference and sledge reference frames.
The progression of the gesture is depicted by: body and pole stick diagrams, trends of reference points positions and their gradients, and body joints trajectories in space. In addition, kinematic biomechanical parameters, such as joints ROM, and technical parameters, such as pole incline and sledge velocity, are reported.
Conclusions: This research demonstrates the feasibility of a markerless kinematic analysis of the poling gesture on a contest field. Results point out a wide variability of the gesture due to the residual functional capabilities and sitting postures of each athlete. However the poling cycles of subjects classified into different classes present similar features. An original segmentation of the double poling gesture in a sequence of three phases is proposed in the paper
Studio della tecnica di spinta su carrozzella sportiva mediante elettromiografia di superficie
No full textSurface electromyography applied to the analysis of training exercises for judokas: an explorative study
No full text
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
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