Perception of kinematic characteristics of tennis strokes for anticipating stroke type and direction     

Shim J  Les Carlton G  Kwon YH 《Research quarterly for exercise and sport》2006,77(3):326-339

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   

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   

School Choice and the Polarization of Public Schools in A Global City: A Bourdieusian GIS Approach     

Ee-Seul Yoon  Cosmin Marmureanu  Robert S. Brown 《Peabody Journal of Education》2020,95(3):229-247

ABSTRACT

Over the past three decades, urban sociologists have shed light on the intensifying social inequality between the wealthiest and poorest neighborhoods in global cities; yet limited research has been done to illuminate the relationships between urban polarization and school choice (i.e., where parents choose schools for their children). This study sociospatially examines the patterns of secondary school choice in the global city of Toronto to illuminate the relationship between urban polarization and school choice. In doing so, this study combines Pierre Bourdieu’s sociospatial theory with a geographic information systems (GIS) approach. Overall, we found that popular schools and schools with specialized choice programs tend to be located in high-status neighborhoods, defined as neighborhoods with residents in the top 20% of family income, home prices, education attainment, and representation from the dominant culture. We also show that mobile students who choose popular schools or highly sought-after specialized programs tend to come from advantaged neighborhoods. Meanwhile, local students who choose a regular school in their neighborhood tend to come from low-status neighborhoods. With a new interdisciplinary approach, this study contributes to a more spatialized understanding of how social inequality and polarization account for school choice.  相似文献   

Social IEP Objectives, Teacher Talk, and Peer Interaction in Inclusive and Segregated Preschool Settings     

Kyong-Ah Kwon  James Elicker  Susan Kontos 《Early Childhood Education Journal》2011,39(4):267-277

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   

PROGRESSIVE EDUCATION AND THE LIMITS OF RACIAL RECOGNITION, REVISITED     

Yoon K. Pak 《Educational theory》2001,51(4):487-497

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Virtual Reality Simulation: Effects on Academic Performance Within Two Domains of Writing in Science     

Lamb  Richard L.  Etopio  Elisabeth  Hand  Brian  Yoon  Sae Yeol 《Journal of Science Education and Technology》2019,28(4):371-381

The purpose of this study was to investigate the role textbooks can play on writing complexity and lexical density as a proxy for critical thinking and ultimately learning, in relation to argumentative and summative writing when integrated with a virtual reality experience. In this study, differences in writing complexity and lexical density scores were measured across four different pedagogical modalities: VR alone, VR followed by textbook readings, textbook readings followed by VR, and textbook readings alone. Adult students, recruited from non-science-based higher education programs, responded to two prompts related to content found in the VR environments and discussed in the textbooks. The authors hypothesized that exposure to a virtual marine environment prior to responding to the writing prompts would enhance both argumentative and summative writing products, when compared to participants who only had access to the textbook experiences. Participants who were exposed to the VR environment then a textbook demonstrated significantly greater writing complexity and lexical density scores than those who had access to VR alone, or access to the text alone.

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Unsupervised word sense disambiguation for Korean through the acyclic weighted digraph using corpus and dictionary     

Yeohoon Yoon  Choong-Nyoung Seon  Songwook Lee  Jungyun Seo 《Information processing & management》2006

Word sense disambiguation (WSD) is meant to assign the most appropriate sense to a polysemous word according to its context. We present a method for automatic WSD using only two resources: a raw text corpus and a machine-readable dictionary (MRD). The system learns the similarity matrix between word pairs from the unlabeled corpus, and it uses the vector representations of sense definitions from MRD, which are derived based on the similarity matrix. In order to disambiguate all occurrences of polysemous words in a sentence, the system separately constructs the acyclic weighted digraph (AWD) for every occurrence of polysemous words in a sentence. The AWD is structured based on consideration of the senses of context words which occur with a target word in a sentence. After building the AWD per each polysemous word, we can search the optimal path of the AWD using the Viterbi algorithm. We assign the most appropriate sense to the target word in sentences with the sense on the optimal path in the AWD. By experiments, our system shows 76.4% accuracy for the semantically ambiguous Korean words.  相似文献   

‘Second death’, or revival of the ‘third world’ in the context of neo‐liberal globalization     

Hee‐Yeon Cho 《Inter-Asia Cultural Studies》2013,14(4):497-509

Abstract

This paper tries to analyze the historical change in the Third World in its emergent stage, in the authoritarian stage and in the current democratic stage and, thereafter, find a way to revive the Bandung spirit in the current globalization context. I define the Bandung spirit as one of a ‘non‐aligned self‐helped “organization against” the dominant powerful countries’; that is, spirit of ‘anti‐predominance’. This spirit has emerged on the base of such domestic orientation and realities as economic self‐reliance, nationally integrated political regime, convergence of the state and civil society around anti‐colonialism. However, according to intensification of the Cold War confrontation on the international level and its centrifugal influence, the early Third World changed to a ‘new’ authoritarian Third World. The Third World in this stage could be characterized by an exclusive authoritarian political regime, dependent‐developmentalist economic orientation and coercively repressed and mobilized, in the top‐down way, civil society. This authoritarian Third World began to be confronted with a strong struggle from the bottom for democratization. In order for democratization of the Third World to become its true revival in the context of globalization, the following tasks should be considered. First, the democratic Third World should be a great driving force for the institutionalization of the transnational public regulatory mechanism. Second, the democratic Third World countries try to go over a kind of ‘transformed’ dependent development strategy. Third, democratization should go along with recovery of political inclusiveness and openness of the state to civil society’s demands. Thereafter, I tried to construct globalist re‐interpretation of the Bandung, by way of conceptualizing the current globalization as imperial globalization, unlike the imperialist globalization which the historical Bandung wanted to confront. I argue that the Bandung spirit of collective self‐help organizations against the newly emerging dominant order should be revived in this worse imperial globalization context. In addition, I argue that a nationalist resistance is also one component of the multiple resistances in the current imperial globalization.  相似文献   

Public library patrons' use of collaborative chat reference service: The effectiveness of question answering by question type     

Nahyun Kwon 《Library & information science research》2007

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Collagen-based brain microvasculature model in vitro using three-dimensional printed template     

Jeong Ah Kim  Hong Nam Kim  Sun-Kyoung Im  Seok Chung  Ji Yoon Kang  Nakwon Choi 《Biomicrofluidics》2015,9(2)

We present an engineered three-dimensional (3D) in vitro brain microvasculature system embedded within the bulk of a collagen matrix. To create a hydrogel template for the functional brain microvascular structure, we fabricated an array of microchannels made of collagen I using microneedles and a 3D printed frame. By culturing mouse brain endothelial cells (bEnd.3) on the luminal surface of cylindrical collagen microchannels, we reconstructed an array of brain microvasculature in vitro with circular cross-sections. We characterized the barrier function of our brain microvasculature by measuring transendothelial permeability of 40 kDa fluorescein isothiocyanate-dextran (Stoke''s radius of ∼4.5 nm), based on an analytical model. The transendothelial permeability decreased significantly over 3 weeks of culture. We also present the disruption of the barrier function with a hyperosmotic mannitol as well as a subsequent recovery over 4 days. Our brain microvasculature model in vitro, consisting of system-in-hydrogel combined with the widely emerging 3D printing technique, can serve as a useful tool not only for fundamental studies associated with blood-brain barrier in physiological and pathological settings but also for pharmaceutical applications.  相似文献