scholarly journals The Experimental Study on Computer Video Feedback in Tennis Serve Teaching Effect

Author(s):  
Zhenkun Zheng
2017 ◽  
Vol 17 (1) ◽  
Author(s):  
Ingeborg Hedegaard Kristensen ◽  
Marianne Simonsen ◽  
Tea Trillingsgaard ◽  
Hanne Kronborg

Author(s):  
Shikun Li

By using video feedback as a treatment, this quasi-experimental study is aimed to capture the dynamic evolution process of teacher candidates' belief of comprehensible input. It compares the changes in teacher candidates' belief of comprehensible input among different feedback groups. A mixed method, which contains the pre and post surveys, semi-structured interviews, and micro-teaching assignments decoding, is used to boost the internal validity of the research design. An ANCOVA analysis was conducted through controlling different co-variances. The results suggest that after the treatment there is no statistically significant difference in teacher candidates' post-treatment belief of comprehensible input. This result is aligned with the patterns that were generalized from semi-structured interviews: 1) a lack of changes in the teacher candidates' belief of comprehensible input after receiving feedback, 2) an alignment between the teacher candidates' micro-teaching performances and their belief of comprehensible input, and (3) the teacher candidates' positive perceptions of the video feedback.


Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.


1962 ◽  
Vol 5 (4) ◽  
pp. 387-394 ◽  
Author(s):  
Bruce Quarrington ◽  
Jerome Conway ◽  
Nathan Siegel
Keyword(s):  

1974 ◽  
Vol 126 (2) ◽  
pp. 243-248
Author(s):  
A WAKABAYASHI ◽  
T KUBO ◽  
K CHARNEY ◽  
Y NAKAMURA ◽  
J CONNOLLY

1963 ◽  
Vol 45 (3) ◽  
pp. 374-383 ◽  
Author(s):  
Donald C. McIlrath ◽  
George A. Hallenbeck ◽  
Hubert A. Allen ◽  
Charles V. Mann ◽  
Edward J. Baldes ◽  
...  
Keyword(s):  

1958 ◽  
Vol 34 (1) ◽  
pp. 11-20 ◽  
Author(s):  
Henry D. Janowitz ◽  
Vernon A. Weinstein ◽  
Rhoda G. Shaer ◽  
James F. Cereghini ◽  
Franklin Hollander

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