• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.361-380
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• 2002

The purposes of this study were to a analysis of friction relation between tennis outsole and tennis playing surfaces. Tennis footwear is an important component of tennis game equipment. It can support or damage players performance and comfort. Most importantly athletic shoes protect the foot preventing abrasions and injuries. Footwear stability in court sports like tennis is incredibly important since it is estimated that as many as 45% of all lower extremity injuries occur in the foot and ankle. The friction force is the force exerted by a surface as an object moves across it or makes an effort to move across it. The friction force opposes the motion of the object. Friction results when two surfaces are pressed together closely, causing attractive intermolecular forces between the molecules of the two different surfaces. The outsole provides traction and reduces wear on the midsole. Today's outsoles address sport specific movements (running versus pivoting) and playing surface types. Different areas of the outsole are designed for the distinct frictional needs of specific movements. Traction created by the friction between the outsole and the surface allows the shoe to grip the surface. As surfaces, conditions and player motion change, traction may need to vary. An athletic shoe needs to grip well when running but not when pivoting. Laboratory tests have demonstrated force reductions compared to impact on concrete. There is a correlation between pain, injury and surface hardness. These are a variety of traction patterns on the soles of athletic shoes. Traction like any other shoe characteristic must be commensurate and balanced with the sport. The equal and opposite force does not necessarily travel back up your leg. The surface itself absorbs a portion of the force converting it to other forms of energy. Subsequently, tennis court surfaces are rated not only for pace but also for the percentage of force reduction.

• The Journal of the Korea Contents Association
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• v.18 no.11
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• pp.171-187
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• 2018

The purpose of this study is to investigate the lifestyle factors influencing behavioral problems such as Inattention, hyperactivity/impulsivity, and internet overuse in elementary and middle school students. Data from 889 elementary school students and 676 middle school students were used and teacher reporting on students' attention deficit and hyperactivity and impulsivity symptoms was also included in the analysis. Lifestyle included opportunities for family interaction, sleep, watching TV, playing Video games, eating breakfast, eating junk food, and private education. As a result of stepwise regression analysis, Video games, junk foods, and family interactions significantly predicted the inattention of elementary and middle school students. Video games, TV, junk foods, and family interactions significantly predicted elementary school students' hyperactivity and impulsivity, but the lifestyle variables hardly accounted for the hyperactivity/impulsivity of middle school students. Video game, and family interactions significantly predicted Internet overuse for both elementary and middle school students. Current study suggest that family interaction opportunities and the use of video games, TV and junk food should be considered to intervene in behavior problems.

• Journal of the Korea Society for Simulation
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• v.19 no.1
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• pp.63-71
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• 2010

In modern war, Intercept Performance of SAM(Surface to Air Missile) is gaining importance as range and precision of Missile and Guided Weapon on information warfare have been improved. An aerial defence system using Surface-to-air Radar and Guided Missile is needed to be built for prediction and defense from threatening aerial attack. When developing SAM, M&S is used to free from a time limit and a space restriction. M&S is widely applied to education, training, and design of newest Weapon System. This study was conducted to develop simulator for evaluation of Intercept Performance of SAM. In this study, architecture of Intercept Performance of SAM analysis simulator for estimation of Intercept Performance of various SAM was suggested and developed. The developed Intercept Performance of SAM analysis simulator was developed by C++ and Direct3D, and through 3D visualization using the Direct3D, it shows procedures of the simulation on a user animation window. Information about design and operation of Fighting model is entered through input window of the simulator, and simulation engine consisted of Object Manager, Operation Manager, and Integrated Manager conducts modeling and simulation automatically using the information, so the simulator gives user feedback in a short time.

• Journal of the Korean Data and Information Science Society
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• v.23 no.5
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• pp.993-1003
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• 2012

The purpose of this study was to estimate the determinants of victory and defeat through analyzing records of Korean men pro-basketball. Statistical models of victory and defeat were established by collecting present basketball records (2010-2011, 2011-2012 season). Korea Basketball League (KBL) informs records of every pro-basketball game data. The six offence variables (2P%, 3P%, FT%, OR, AS, TO), and the four defense variables (DR, ST, GD, BS) were used in this study. PASW program was used for logistic regression and Answer Tree program was used for the decision tree. All significance levels were set at .05. Major results were as follows. In the logistic regression, 2P%, 3P%, and TO were three offense variables significantly affecting victory and defeat, and DR, ST, and BS were three significant defense variables. Offensive variables 2P%, 3P%, TO, and AS are used in constructing the decision tree. The highest percentage of victory was 80.85% when 2P% was in 51%-58%, 3P% was more than 31 percent, and TO was less than 11 times. In the decision tree of the defence variables, the highest percentage of victory was 94.12% when DR was more than 24, ST was more than six, and BS was more than two times.

• Health Policy and Management
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• v.16 no.2
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• pp.96-116
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• 2006

To assess the economic value of pharmaceutical therapy with Kremezin, we investigated the maximum amount of willingness-to-pay (WTP) of patients with chronic renal failure (CRF) for a hypothetical effect of Kremezin in delaying the initiation of dialysis treatments. A face-to-face survey was carried out in a sample of 141 CRF patients from 2 dialysis centers, composed of 82 hemodialysis patients, 38 peritoneal dialysis patients, and 21 non-dialysis CRF patients. Using a bidding game method with a starting point of 320,000 Won, which is the average monthly out-of-pocket payment for dialysis treatment, we asked the study subjects how much they would pay per month to receive Kremezin therapy. The mean out-of-pocket monthly WTP for Kremezin was 310,000, 430,000, and 520,000 Won (p<0.05, repeated one-way ANOVA)) when Kremezin delays the initiation of dialysis treatments by 1, 2, and 4 years. Significant correlation between the respondent's WTP and income $(r=0.266{\sim}0.368,\;p<0.05)$ confirmed the construct validity of the WTP instrument. Regression results showed that patients with a higher education, with diabetes as a major causes of CRF, and undergoing hemodialysis treatments tended to express higher WTP for Kremezin. The economic value of WTP from the perspective of patients varied from 310,000 to 520,000 Won depending on the effect size of Kremezin. The mean WTP was higher than 32,000 Won, only when the hypothetical effect of Kremezin in delaying the initiation of dialysis is for 2 years. This implies that Kremezin might be the preferred choice of therapy by CRF patients if it delays the initiation of dialysis treatment for at least 2 years.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3085-3093
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• 2012

The purpose of this study is to examine difference in knowledge level, attitude and performance competence on CPR (Cardiopulmonary Resuscitation) in football players. For this, questionnaire survey was carried out from October 5, 2011 to October 19 targeting 234 football players of high schools and universities where are located in Seoul, Gyeonggi, and Gangwon-do Province. The collected data was carried out frequency, t-test ANOVA, and correlation analysis by using SPSS/PC 19.0 for Windows. All the statistical analyses were set for significance level in p<.05. The results are as follows. Knowledge level, attitude and performance competence on CPR according to football players' general characteristics were indicated to have influence upon gender, academic background, and the appearance of educational experience in CPR. It was indicated that there is difference between CPR-related characteristics, and knowledge level, attitude & performance competence. Also, it was indicated that there is correlation among knowledge level, attitude and performance competence on CPR in football players. Based on these results, it accurately grasps experience and knowledge level on CPR in football players, thereby making a place available for having a game with security, resulting in being considered to possibly make the better sports.

• Korean Journal of Childcare and Education
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• v.10 no.2
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• pp.111-131
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• 2014

This study aims to research the use of smart devices of infants and preschool children, and their mothers' perception about it. Moreover, the goal of this study is to collect preliminary data about problems from the use of smart devices, and to prevent the problems. Therefore, the questions of inquiry for this study are: 1. How do infants and preschool children use smart devices? 2. How do mothers perceive their children using smart devices? Four hundred and forty mothers, who send their child to a day-care center or kindergarten in Busan, participated in this research and data among 397 of them were analyzed using PASW 18.0 program. The answers to a multiple-choice question were converted into a frequency and percentage. To verify the difference of factors, Chi-squared Test and One-way Analysis of Variance methods were used. The following are findings of this study: 1. Most of the families owning smart devices allow their children to use a smart device when children want it, and children use it for entertainment purpose before their bedtime. Children start to use a smart device mostly around the age of 4. Compared to girls, boys spend a longer time on smart devices playing mobile game. In addition, the research indicated that the children of younger mothers tend to use smart devices in earlier ages than the children of elder mothers. 2. Mothers of preschool children have higher perception about the availability of their child using smart devices compare to the mothers of day-care center. However, the research showed that elder mothers have more positive perceptions about all the other five lower factors, (e.g. educational characteristic, entertainment characteristic, design, safety, and smart recognition).

• Journal of the Korea Convergence Society
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• v.12 no.3
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• pp.325-339
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• 2021

The purpose of the study is to examine sports-related cognitive functions through a systematic review and to suggest effective instruments to measure the cognitive functions. The present study was conducted based on the systematic review and meta-analysis protocol-the PRISMA. Of 429 articles searched through keywords from 2008 to 2020, 45 articles that met the selection criteria were analyzed. It was revealed that athletes had better cognitive functions than non-athletes, that the higher the sports expertise was, the higher the cognitive functions, and that there were differences in cognitive functions according to the sport types. The primary cognitive functions related to sports performance summarized as executive functions (inhibition ability, cognitive flexibility), information processing speed, spatial ability, and attention. As tasks for measuring each cognitive function, a stop signal task for inhibition ability, a design flexibility task for cognitive flexibility, a simple and choice reaction time test for information processing, a mental rotation task for spatial ability, and an attention network test for attention are appropriate.

• Korean Journal of Health Education and Promotion
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• v.18 no.3
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• pp.37-58
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• 2001

This study placed its objectives in suggesting the basic data for setting up an approach to protect the educational environment, by analyzing the relevance between the misconducts of adolescence and the harmful environment around the school, as an object of study, middle school students and high school students all over the country. Thus, this study carried out the questionnaire survey, by the multi-stage of stratified sampling in 2,114 middle school and high school students from June 29, 2000 through July 29, 2000. And the results of analysis were as follows: 1. In case of the ratio of students using harmful environment, the electronic game room had the highest ratio (78.3％); next, the PC room (75.6％), the singing room (71.6％), and the cartoon room (34.3％). 2. In terms of the experiences of using the harmful environment according to the personal characteristics, high school students used it in a higher ratio, compared with middle school students (p〈0.001); the students, whose father graduated from a high school, comparatively used it much more(p〈0.05). Also, when a school is located near to amusement quarters or shopping centers, students used the harmful environment most highly (p〈0.001). And the differences were found to be statistically significant. 3. In case of the perceived susceptibility factors, the harmful environment was found to be used in lower ratio, by the students who answered “very so” to the question item, The more harmful environment facilities are positioned around school, the more student have the opportunities to use them. (p〈0.001). That is, the findings showed that the higher students' degree of perceived susceptibility factors was the less students used harmful environment facilities. The differences were statistically significant. In terms of the ratio of using harmful environment according to perceived seriousness factors, it was founded out that the students, who answered, “If I use any harmful environment facilities, it will be very harmful to myself.”. had the less opportunities of having used them, compared with the students who did not answer so (p〈0.001). This indicated that the higher the degrees perceived seriousness of students, the less they used harmful environment facilities. And the differences were statistically significant. In the side of the ratio of using harmful environment according to the perceived barriers, it was found out that there were any special large differences. That is, perceived barriers had nothing to do with students' using harmful environment. 4. As the result of having analyzed the factors influencing the behaviors of using harmful environment, the factor to explain the behaviors of using harmful environment was found to be the degree of perceived seriousness, among individual perceiving factors; next, the location of a school - one of personal characteristics, the degree of perceived susceptibility and ages, m sequence. 5. Among students' misconduct experiences, drinking was highest (21.6％), next, smoking (11.9％), drug abuse (4.3％), and sexual relations (1.6％), In sequence. Among other problematic behaviors, excessive waste was highest (14.6％); next, disobedience and lie (10.7％), night wandering (7.8％), and bad dressing and making-up (5.5％), in sequence. 6. In terms of the misconducts according to the behaviors of using harmful environment, compared with the students who did not commit any misconducts, harmful environment facilities were used more highly, by each group of students who experienced drinking (p〈0.00l), smoking (p〈0.001), sexual relations (p〈0.05), excessive waste (p〈0.001), disobedience ＆ lie (p〈0.001), and bad dressing ＆ making-up (p〈0.05). And the differences were statistically significant.

• The Journal of the Korea Contents Association
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• v.17 no.12
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• pp.461-472
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• 2017

The purpose of this study is to analyze the current status and condition of children's playgrounds in K which parents recognize as in Gyeonggi-do and provide basic data for the qualitative environment for daily outdoor play of young Children. To do so, a survey of 269 parents living in Gyeonggi-do was conducted and reconstructed based on the advanced research related to outdoor play. Also it was evaluated and revised after consultation with 3 children education specialists. The repossessed questionaries were frequency-analyzed with SPSS 20.0 program. The result of the analysis on outdoor playgrounds is in the following. First of all, it was analyzed that parents required 1 or 2 hours for their children to play outdoors in a type of "forest playgrounds." Moreover, they said that it was really important for the children to feel "interesting and funny" during the outdoor play, and they recognized that the play would be helpful for the children's socialization. However, they felt that a risk factor of the outdoor play was "a vehicle risk in streets." Secondly, the study suggested that there were outdoor playgrounds around parents' houses, and a type of the outdoor play was "a playground installed in the apartment complex." Furthermore, most of the parents weren't satisfied with the outdoor play because the apartment neglected the management of the playgrounds, and there were no playing facilities that were good enough to derive children's curiosity and adventurous spirit. The result also showed that most of the children played outdoors with "their mothers," and they participated in indoor activities, especially playing a game or watching TV rather than outdoor activities after attending a children educational institute. Lastly, when it comes to areas of outdoor play to be improved, it was necessary to "expand playgrounds that children can use for each season," build "safe playgrounds" for a type of the outdoor play," provide "playing spaces" for a spatial type, and "control vehicles around the playgrounds and deal with dangerous things" to prevent safety accidents. The result can expand the understanding of outdoor play for Young Children and offer discussions about the relevant organizations and studies.