1,721,131 research outputs found
The BEM for numerical solution of partial fractional differential equations
No full textAbstractA numerical method is presented for the solution of partial fractional differential equations (FDEs) arising in engineering applications and in general in mathematical physics. The solution procedure applies to both linear and nonlinear problems described by evolution type equations involving fractional time derivatives in bounded domains of arbitrary shape. The method is based on the concept of the analog equation, which in conjunction with the boundary element method (BEM) enables the spatial discretization and converts a partial FDE into a system of coupled ordinary multi-term FDEs. Then this system is solved using the numerical method for the solution of such equations developed recently by Katsikadelis. The method is illustrated by solving second order partial FDEs and its efficiency and accuracy is validated
Footwork technique used in elite table tennis matches
Full text linkNotational and Match analysis are very well-recognized methods to collect information about the most common
technical-tactical performance indicators in table tennis: footwork and stroke types. The aim of this study was to
compare footwork distributions in men (M) and women (W) elite table tennis competitions. Nine men’s and nine
women’s matches were analyzed. All players were in the top 120 (M) and 111 (W) positions of the ITTF world
ranking. An expert coach analyzed game video recordings in slow motion with the software Kinovea and collected
data about the footwork types used by the players during the games. The results showed differences between M
and W: M prefer to use one step (35.6%, W: 21.9%), W prefer to hit the ball without performing any step (W:
40.2%, M: 20.4%), the chassé is equally used (M: 19.7%, W: 21.7%), and the crossover is mainly used by M
(11.1%, W: 3.7%). The pivot is mainly used by M (9.9%, W: 7.8%), and W prefer the slide (4.9%, M: 3.2%). In
conclusion, this study can be useful for physical trainers, performance analysts, and coaches, to design specific
footwork training sessions for M and W elite table tennis players
Serve analyses of elite European table tennis matches
Full text linkThe purpose of this study was to analyze the serve activities of elite European table tennis players. Twenty matches (78 games, 1466 points) of semifinal and final German League and Europe TOP 16 in men’s (in the top 30 of ETTU Rank list) were analyzed. Differences in serving activities (type, stroke type, outcome and placement) were analyzed according results outcome of match, game, point, phase of the game and type of games. Results showed that forehand short serve prevailed (76.9%) instead other types of serve, mostly placed in the middle of the table on the opponent’s backhand side. Percentage of point won directly with serve was 11.6%, points won with 3rd stroke - 22.4% and points won with 5th stroke after serve (10.9%). Lost points after serve mostly were after 3rd stroke (25.0%) and after 5th stroke (22.4%) and serve errors were noted in 1.5% of all analyzed points. In the 3rd phase of the game serve points were won mostly with 3rd and 5th stroke instead previous phases of the game. Results of Pearson’s chi-squared test showed an association between match outcomes and serve type and outcome, serve type and outcome considering phase of the game and different type of games with serve type, outcome and placing zones
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
- …
