• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.65-75
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• 2002

The study has a goal that produces abundant documents that needed for athletes to teach and progress skills by analyzing 3-dimensional action analysis of C-difficulties Ring jump included in body original elements among techniques constructing Rhythmic Sport Gymnastics. 1. It was the longest applied time delay that E-3 indicates 0.409${\pm}$0.017sec in each event applied time delay. 2. It was the tallest height that E-3 indicates 88.5${\pm}$1.3% in displacement of body's center. 3. It was the fastest velocity in E-2 where the velocity of left foot is 732.4${\pm}$46.1cm/sec, the velocity of right foot is 1958.4${\pm}$25.1cm/sec. 4. the lowest angle was founded at 97.8 degree in the E-3 on the trunk extension angle. 5. The lowest angle of both sides were seen at 92.8${\pm}$14.9degree and 69.2${\pm}$5.7degree in the E-3 on the each displacement of knee joint. 6. The highest angle of both sides were seen at 171.3${\pm}$6.9degree and 167.9${\pm}$8.4degree in the E-3 on the each displacement of ankle joint As a result of these studies, by jumping with ankle joint extension to accomplish the Ring jump action, it is considered to have the time of flexiblity and staying in the air which we can see in a back.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.327-340
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• 2003

The purpose of this study was to investigate the height of jump, angle of the ankle and knee, the angular velocity of the ankle and knee between two types of ballet shoes during a jump in the 1st position. The subjects were 5 female ballet majors of university in Busan the majors who have been dancing ballet for six years on the average. The conclusions are as follows: 1. The height of jump had no significant difference between two types of ballet shoes, and then the average of the height of jump with point shoes group ($20.24{\pm}4.62\;cm$) was a little higher than ballet shoes group ($17.50{\pm}4.05\;cm$). 2. The angle of the ankle had no significant difference for all events between two types of ballet shoes. The minimum angle of ankle joint was represented to $54.36_{\circ}$ at the E1 of the left ankle angle of the ballet shoes and the maximum value was showed $155.43_{\circ}$ at the E3 of the right ankle angle of the point shoes. 3. The angle of the knee had no significant difference for all events between two types of ballet shoes. The minimum angle of knee joint was represented to $99.54_{\circ}$ at the E1 of the left knee angle of the ballet shoes and the maximum value was showed $174.25_{\circ}$ at the E3 of the right knee angle of the point shoes. 4. The ankle velocity of the ankle had no significant difference for all events between two types of ballet shoes. The minimum angular velocity of the ankle was represented to 4.35 deg/s at the maximum height(E3) of the point shoes and the maximum value was showed 597.81 deg/s at the take-off(E2) of the right ankle angle of the point shoes. 5. The angular velocity of the knee had significant difference between two types of ballet shoes at the event 1(p<.05). The minimum angular velocity of the hee was represented to -1.68 deg/s at the maximum height(E3) of the point shoes and the maximum value was showed 360.25 deg/s at the take-off(E2) of the left knee angle of the ballet shoes. The other events had no significant difference between two types of ballet shoes.

• Journal of Chest Surgery
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• v.38 no.10 s.255
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• pp.717-720
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• 2005

Here we report a case of posterior left ventricular (LV) free wall rupture following postinfarct ventricular septal rupture (VSR). A 58-year-old man was transferred to the hospital under the impression of acute myocardial infarction. Posterior VSR was seen on echocardiographic examination. The intraaortic balloon pump catheter was introduced percutaneously and the emergent operation was proposed. Sudden circulatory collapse was developed shortly after the anesthetic induction and the patient's chest was hurriedly opened while on cardiopulmonary resuscitation. The acute cardiac tamponade was seen and the blood was seen pumping from the longitudinal tear at the mid-level of LV posterior wall, measuring 2 cm in length. The cardiopulmonary bypass was set and LV reconstruction was done. The postoperative recovery was delayed due to the brain injury presumably caused by preoperative cardiac arrest.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.344-353
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• 2016

The cause of abnormal tidal residuals was examined by analyzing sea levels, sea surface atmospheric pressures, winds at ten tide stations, and current, measured at the coast of the Yellow Sea from the night of November $24^{th}$ to the morning of the $25^{th}$ in 2013, along with weather chart. Additionally, the cross-correlations among the measured data were also examined. The 'abnormal tidal residuals' mentioned in this study refer to differences between maximum and minium tidal residuals. The largest abnormal tidal residual was identified to be a difference of 176 cm occurring over 4 hours and 1 minute at YeongJongDo (YJD) with a maximum tidal residual of 111 cm and minimum of -65 cm. The smallest abnormal tidal residual was 68 cm at MoSeulPo (MSP) during 8 hours 52 minutes. The cause of these abnormal tidal residuals was not a meteo-tsunami generated by an atmospheric pressure jump but wind generated by the pressure patterns. The flow speed due to these abnormal tidal residuals as measured at ten tide stations was not negligible, representing 16 ~ 41 % of the annual average ebb current speed. From the cross correlation among the tidal residuals, winds, and tidal residual currents, we learned the northern flow, due to southerly winds, raised the sea level at Incheon when a low pressure center located on the left side of the Korean Peninsula. After passing the Korean Peninsula, a southern flow due to northerly winds decreased the sea level.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.7B
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• pp.679-689
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• 2006

Delivering multicast stream is one of the cost-saving approach in the large scale VOD environment. Because implementing VCR-like interactions for user's convenience in the multicast streaming system involves complex problems, we need the proper solutions for them. In this paper, we propose a hybrid scheme which uses the general P2P and the patching scheme with the Collaborative Interaction Streaming Scheme(CISS). CISS provides jumping functionability to the appropriate multicast session after VCR-like interaction in the environment in which multiple peers transmit VCR-like interaction streams to the VCR-like functionability request node to reduce the loads generated by frequent join or departure of peers at the multicast tree during providing VCR-like functionability. Therefore, with the proposed scheme we can distribute network traffic and reduce control overhead and latency. And to evaluate the performance of proposed scheme we compare it in the aspect of the performance of streaming delivery topology, control overhead and streaming quality with P2Cast[10] and DSL[11]. The simulation result shows that proposed P2Patching reduces about 30% of process overhead and enhances about $25{\sim}30%$ of streaming quality compared with DSL.

• Korean Journal of Applied Biomechanics
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• v.18 no.4
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• pp.1-19
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• 2008

This research is to analyze the force on landing 3 Type of Halfpipe Curves(Ellipse, Circle, Brachistochrone) based on the mechanical calculation of normal force on a sloping surface. Jumping off a platform on a bard horizontal surface, the flexing of the legs, the softness of the snow, the angle of the landing surface, initial velocity and the forward motion of the snowboarder can contribute to reducing the force on landing. But halfpipe is significantly determined by the curvature of surface. It is definitely verified that the Brachistochrone curve is more safety than others. However currently using the Ellipse curve is mostly safe too. If we consider the efficiency of construction, we can easily think there is no use of another curves except normal ellipse curved halfpipe. It would better that geometrically verity curved halfpipe should be designed for improving fluent skills to snowboarders. This methode of research can be a model of scientifical research on sports safety how can sportsman reduce critical injury by designing optimal halfpipe facilities and manual.

• Journal of the Korea Convergence Society
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• v.9 no.9
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• pp.309-317
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• 2018

The purpose of this study was to investigate the effect of bone age on physique and physical fitness in elementary school students. For this purpose, the structural equation model test was conducted based on the three-year longitudinal study. The results were as follows. First, bone age in boys and girls (1st~3rd grade) has a direct effect on the change of body size, but it does not affect the change of physical strength. Second, the bone age of the senior male students(4~6 grade) gave a direct effect on the change of physique, 50m running, and sit-up. On the other hand, it gave an indirect effect on push-ups, sitting basketball throws, and standing long jump. Third, the bone age of the female students(grades 4~6) affected directly on body size change, sit-up, side step and indirect effect on 50m running, half squat jump, and standing long jump. These results indicated that the evaluation of the bone age of the subjects should be included in the exercise ability evaluation items for the male and female students in elementary school over the fourth grade in relation to the myofunction.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.734-742
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• 2016

Purpose : The present study was aimed at investigating the plantar pressure on dynamic balance of subjects with functional ankle instability following fatigue of lower leg. Methods : The subjects(30 university students) were divided into 2 groups ; functional ankle instability group(7males and 7females) and ankle stable group(9males & 7females) who could evaluate questionnaire. All the participants were evaluated muscle fatigue of lower leg by Biodex system III and distribution of plantar pressure by Zebris FDM-S system, The dynamic balance was tested by single-leg jump landing. This study were to measure of plantar pressure on dynamic balance with the difference between FAIG and control group following muscle fatigue. Results : In functional ankle instability group(FAIG), the post-fatigue was significantly higher than pre-fatigue in forefoot(p2,p3,p4) of plantar pressure on dynamic balance(p<0.05). The FAIG was significantly higher than the ASG in forefoot(p2, p3, p4) & lat midfoot(p6) of plantar pressure after fatigue in dynamic balance(p<0.05). The FAIG was significantly longer than the ASG in anteroposterior(AP) & mediolateral(ML) distance on center of pressure(CoP) after fatigue in dynamic balance(p<0.05). Conclusion : This study showed that FAIG were effected plantar pressure and center of pressure(CoP) by dynamic balance following muscle fatigue. Further study is needed to measure various age & work with ankle instability for clinical application.

• Journal of Korean Orthopaedic Sports Medicine
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• v.5 no.2
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• pp.129-134
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• 2006

Purpose: In the professional soccer team, we performed pre-seasonal physical examination and analyzed the results to establish a standardization data in relation to their position. Materials and Methods: We performed physical examination to the professional soccer team, consisted 34 player's average age 24.9 years. The examination performed were questionnaire on history, musculoskeletal examination, muscle power test, physiologic test, functional test. Results: According to the relationship between player position and injury pattern,. Knee injuries are most frequent on history. Physical examination outcome was that forward were prone to flexor hallucis longus tendinitis, midfielder for chronic ankle instability, defender for achilles tendinitis. Isokinetic test was done at dominant side, Peak torque to body weight ratio was 55.1%. Physiologic test checked body fat percentage was midfielder was superior as 19.8 (SD 2.9). Functional test out-come was that back strength 125 N. sergeant jump 59.6 cm, reaction time 208.5 sec, flexibility 19.2 m/s, side step 39.9 cm. Conclusion: Pre-seasonal physical examination gave us the standardization data and preventive measurement could be advocated from this results.

• Journal of Life Science
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• v.19 no.12
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• pp.1821-1828
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• 2009

The purpose of this research was to investigate how the plyometric training and weight training program, applied in the field for exercise performance of throwing players, influenced improvement of athletic abilities, including agility, maximum muscular power, and strength. After implementing plyometric training and weight training to 21 high school throwing players for 10 weeks, we designed the next step. The 21 subjects were divided into two groups - women's group and men's group. All subjects were tested to determine agility using sidestep, burpee test, reaction time, lower body power and strength using standing long jump, standing jump, 30 m running, squats and leg presses. Additionally, isokinetic strength was measured using Cybex isokinetic dynamometer. The results showed that both groups demonstrated improvement in the standing long jump, standing jump and 30 m running after training. Particularly, the women's group indicated better improvement. Second, women's groups showed higher improvement in the sidestep and burpee test. However, in the reaction time test, the men's group indicated better improvement. Third, both groups showed better improvement in squats and leg presses after training. Particularly, the women's group indicated better improvement. Fourth, in the left and right side extension torque and flexion torque at a velocity of $60^{\circ}$/sec, both groups showed better improvement after training. In the left side extension peak torque, the men's group showed higher improvement, but the women's group showed higher improvement in the left side flexion and extension peak torque. Fifth, both groups showed better improvement in bench pressing and back strength after training. Particularly, the women's group indicated higher improvement.