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1.
Perception of kinematic characteristics of tennis strokes for anticipating stroke type and direction
The purpose of this study was to determine the sources of visual information used by highly skilled tennis players in anticipating their opponent's shots. In Experiment 1, motion analysis of the strokes showed that the relative motion between the racquet and forearm was different between the ground strokes and lobs, but there were no reliable kinematic differences when shot direction was varied. In Experiment 2, 12 skilled tennis players observed the opponent hitting strokes in a normal video or in a point-light display with different segments occluded. Players' anticipation accuracy was not degraded by the use of the point-light display. Occluding the racquet and forearm significantly reduced the participant's ability to determine the type of stroke produced. 相似文献
2.
Effects of light refraction on the accuracy of camera calibration and reconstruction in underwater motion analysis 总被引：1，自引：0，他引：1
Kwon YH Casebolt JB 《Sports biomechanics / International Society of Biomechanics in Sports》2006,5(2):315-340
One of the most serious obstacles to accurate quantification of the underwater motion of a swimmer's body is image deformation caused by refraction. Refraction occurs at the water-air interface plane (glass) owing to the density difference. Camera calibration-reconstruction algorithms commonly used in aquatic research do not have the capability to correct this refraction-induced nonlinear image deformation and produce large reconstruction errors. The aim of this paper is to provide a thorough review of: the nature of the refraction-induced image deformation and its behaviour in underwater object-space plane reconstruction; the intrinsic shortcomings of the Direct Linear Transformation (DLT) method in underwater motion analysis; experimental conditions that interact with refraction; and alternative algorithms and strategies that can be used to improve the calibration-reconstruction accuracy. Although it is impossible to remove the refraction error completely in conventional camera calibration-reconstruction methods, it is possible to improve the accuracy to some extent by manipulating experimental conditions or calibration frame characteristics. Alternative algorithms, such as the localized DLT and the double-plane method are also available for error reduction. The ultimate solution for the refraction problem is to develop underwater camera calibration and reconstruction algorithms that have the capability to correct refraction. 相似文献
3.
The purpose of this study was to examine: (a) the role of teacher talk in promoting peer interaction, (b) the adequacy of
social IEP objectives to reflect children’s social functioning and guide provision of teacher talk, and (c) differences in
children’s peer interaction and teacher talk in inclusive and segregated settings. Thirty children with disabilities and their
teachers participated. Overall, we observed low rates of teacher talk thought to support peer interaction; however, when teachers
verbally facilitated peer interaction, children were observed interacting more frequently with peers. Children’s social IEPs
accurately reflected their current level of social functioning. However, the social IEPs appeared to fail to influence teacher
intervention. Finally, children with disabilities in inclusive settings interacted with peers more than children in segregated
settings, even though there was no significant difference in amount of teacher talk in the two settings. 相似文献
4.
5.
Yoojin Kwon Michelle Lemieux Jill McTavish Nadine Wathen 《Journal of the Medical Library Association》2015,103(4):184-188
Objective
The purpose of this study was to compare effectiveness of different options for de-duplicating records retrieved from systematic review searches.Methods
Using the records from a published systematic review, five de-duplication options were compared. The time taken to de-duplicate in each option and the number of false positives (were deleted but should not have been) and false negatives (should have been deleted but were not) were recorded.Results
The time for each option varied. The number of positive and false duplicates returned from each option also varied greatly.Conclusion
The authors recommend different de-duplication options based on the skill level of the searcher and the purpose of de-duplication efforts. 相似文献6.
Kwon Wonju Ha Jung Hee Jang Hansori Lee Donghun 《International journal for the advancement of counseling》2022,44(2):283-297
International Journal for the Advancement of Counselling - The current study investigated the mediation effect of self-focused attention on the relationship between South Korean novice... 相似文献
7.
This paper addresses synchronization problem for discrete-time complex dynamical networks with interval time-varying delays. In order to achieve the synchronization, a feedback controller subjected to randomly occurring perturbations will be considered. The randomly occurring perturbations are assumed to belong to the Binomial sequence. By constructing a suitable Lyapunov–Krasovskii functional, and utilizing reciprocally convex approach and Finsler?s lemma, the synchronization criteria for the networks are established in terms of linear matrix inequalities (LMIs) which can be easily solved by various effective optimization algorithms. The networks are represented by the use of Kronecker product technique. The effectiveness of the proposed methods will be verified via numerical examples. 相似文献
8.
Educational assessment in the Republic of Korea reflects social and cultural perspectives, as most assessments are considered as a ‘gatekeeper’ of one’s success in life, in terms of entering an elite school or having a better career. This paper presents a profile of the education system, especially focusing on the college entrance examination system in the Republic of Korea, and discusses the washback effect of the high-stake exam, the College Scholastic Ability Test, on stakeholders and the entire society. Furthermore, this paper will discuss the ways to improve the education policy, particularly the college entrance system, with emphasis on implications for future assessment reform from a standardised high-stake test to move towards the formative assessment. 相似文献
9.
Forward citations of patents have been used extensively to capture the impact of technological knowledge. However, our understanding of the factors shaping patent citation patterns remains limited. One of the main limitations is the lack of scholarly attention paid to the dynamic influences arising from the evolution of technology fields. From an evolutionary perspective, technological impact is not simply determined by the static attributes of a technology itself; it is also dynamically affected by changes in the external conditions. Drawing on this viewpoint, this study suggests a model for understanding patent citation patterns by reflecting the evolution of the technology fields to which each patent belongs. Four such factors are explored: technology cycle time, potential of technological convergence, popularity of the technology field, and technological novelty. Based on the proposed model, we show how expected citation patterns can change as a result of different scenarios for technology field evolution. We conduct a case study of patents in the information technology and healthcare industries to show citation patterns of patents across heterogeneous industries as well as those within an industry. Contributions to the innovation literature and research investment decisions are discussed. 相似文献
10.
Kwon YH Como CS Singhal K Lee S Han KH 《Sports biomechanics / International Society of Biomechanics in Sports》2012,11(2):127-148
The purposes of this study were (1) to determine the functional swing plane (FSP) of the clubhead and the motion planes (MPs) of the shoulder/arm points and (2) to assess planarity of the golf swing based on the FSP and the MPs. The swing motions of 14 male skilled golfers (mean handicap = -0.5 +/- 2.0) using three different clubs (driver, 5-iron, and pitching wedge) were captured by an optical motion capture system (250Hz). The FSP and MPs along with their slope/relative inclination and direction/direction of inclination were obtained using a new trajectory-plane fitting method. The slope and direction of the FSP revealed a significant club effect (p < 0.001). The relative inclination and direction of inclination of the MP showed significant point (p < 0.001) and club (p < 0.001) effects and interaction (p < 0.001). Maximum deviations of the points from the FSP revealed a significant point effect (p < 0.001) and point-club interaction (p < 0.001). It was concluded that skilled golfers exhibited well-defined and consistent FSP and MPs, and the shoulder/arm points moved on vastly different MPs and exhibited large deviations from the FSP. Skilled golfers in general exhibited semi-planar downswings with two distinct phases: a transition phase and a planar execution phase. 相似文献