• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.653-660
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• 2011

The purpose of this study was to compare selected kinematic variables between male medalists and a Korean male javelin thrower at the IAAF World Championships, Daegu 2011. The three medalists and one Korean javelin thrower that participated in the Championships were videotaped using three high-speed cameras (300 frames/s, EX-F1 Exilim, Casio, Japan). The results showed that the release and attitude angles of the Korean male javelin thrower (KMJT) were greater than that of the medalists, whereas the attack angle of the KMJT was smaller than that of the medalists. This study also found that the KMJT clearly had a lower release height than the medalists. As a possible adaptation of his physique to the skill, the KMJT used a small trunk inclination angle and produced greater inclination angles at his upper extremities. These results may be linked to an increase in the release angle of the KMJT. There were some difference between the KMJT and the medalists in terms of the length and duration of the delivery phase. In harmony with the shorter length of the delivery phase, its duration was shorter for the KMJT in comparison to the medalists. Because the delivery stride is considered to be a primary generator of endpoint speed, this decrease in the delivery phase time would decrease the javelin velocity at release. The amount of time taken in the delivery phase may be a critical factor to enhance a javelin thrower's performance. Thus, rhythmic movement training specifically designed for the KMJT will help him attain an optimal throwing position.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.53-63
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• 2006

The general objective of this study was to investigate biomechanical characteristics of bowling swing using three-dimensional cinematography. This study focused specifically on movements of the upper body segments during a bowling swing. Eight elite female bowling players participated in this study. Subjects performed bowling swing and their performance was sampled at 60 frame/sec using two high-speed video cameras with a synchronizer. After digitizing images from two cameras, the two-dimensional coordinates were used to produce three-dimensional coordinates of the 12 body segments (20 joint reference makers). The obtained three-dimensional coordinates were fed to a custom-written kinematic and kinetic analyses program (LabView 6.1, National Instrument, Austin, TX, USA). The analyses determined the linear and angular kinematic variables of the body segments with which joint force and torque of the lower and upper trunks and the shoulder were estimated based on the Newton-Euler equations. It was found that during the bowling swing the peak linear velocities of the body segments were reached in sequence the trunk, the shoulder, the elbow, the wrist, and the bowl. This result indicates that linear momentum of the lower body and the trunk transmits to the arm segment during the bowling swing. The joint torques of the torso and the arm occurred almost simultaneously, indicating that bowling swing seem to be a push-like motion, rather than a proximal-distal sequence motion in which many of throwing motions are categorized. The ultimate objective of the bowling swing is to release a heavy-weight bowl with power and consistency. Therefore, the bowling swing observed in this study well agrees with that bowlers use the stepping to increase the linear velocity of the bowl, the simple pendulum system and the push-like segmental motion in the torso and the arm segment to enhance the power at the release of the bowl.

• Korean Journal of Applied Biomechanics
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• v.21 no.5
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• pp.645-652
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• 2011

The purpose of this study was to analyze, in real time, the glide motion and release motion of domestic athletes and gold and bronze medalists employing the glide technique for the men's shot put at the Daegu World Athletic Championship in 2011. In the glide motion, the Korean athletes had a relatively high body center and shot put heights and lager stretching angles for their hips and knees. In the delivery phase, which shifts to the release phase, the Korean athletes showed slower vertical body center and shot put speeds, and they changed the phase, to the release phase by using a small body angle. In the release phase, the Korean athletes showed differences in their projection speeds and vertical body center speeds. The world-famous players showed high angle speeds, which refer to the composition of the rotation force at the moment of release (body, hip, and shoulder line). In the release phase, the Korean athletes did not have fully stretched hip and knee angles, which might have negatively influenced the vertical speed. Because the Korean athletes showed relatively low projection heights and projection angles. it was found that they need to enhance the muscular power of their, throwing arms and lower limbs.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.2
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• pp.811-819
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• 2013

This study aims to analyze determinants of mountainous and coastal area's housing value caused by the characteristics of the natural environment. As the current issue of housing value is throwing the spotlight on the climate change recently, environmental features are significantly important than before. There were a lot of studies on the influence of environmental characteristics to the housing price but these studies were mostly dealing with the housing price in especially apartments nearby Han-river in Seoul, South Korea. To have differences with existing studies, environmental characteristics estimating housing value are classified as 8 elements including the view, the wind speed, and the humidity. The result of this study is in following; there were few significant environmental variables in mountainous housing value growth model. This means people living in mountainous area recognize on environmental factors more such as housing or complex characteristics. People living in coastal area are much more sensitive environment variables in their residence value than mountainous area. Especially, the view for the ocean is the most important variable in housing value, and wind speed is second positively significant. Humidity and safety of disaster are negatively significant variables.

• The Korean Journal of Physiology
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• v.2 no.2
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• pp.101-135
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• 1968

As physical fitness measured was muscle strength (hand grips, leg extention, back lift, and arm pull and thrust), skinfold thickness (5 different sites), circulatory function (resting heart rate and blood pressure), speed (kinesiological analysis during 100m sprint, record, maximal and final speed), motor function (50 meter dash, ball throwing, standing broad jump, and pull-ups), maximal aerobic power (maximum oxygen intake by field running method), muscle power (leg and arm by inertia ergometer), and general endurance (maximum endurance running time on the treadmill at the speed of 5 MPH and grade of 15.5%) of 1131 Korean children (boys 572, girls 559) aged of 6 to 17 years, who were randomly sampled from 24 primary, middle and high schools at the two districts of Seoul and KyungKi. The results are summarized as follows: 1) The status (height and weight) of the children was almost same as that of the previously reported Korean and Japanese children of same ages. 2) Muscle strength was a gained linearly with geting age in the boys and girls but there was a little improvement in girls aged of 13 years or more. 3) The mean skin fold thickness was increased linearly with geting ages in both sexes, but the girls from 12 to 17 years of age were increased rapidly, and maximum value was 17mm, while boys was 7.0 mm. 4) In the circulatory function, the resting heart rate was decreased, but the blood pressure was increased with ages in both sexes within the normal limits. 5) The maximum and final speed during 100 meter sprint increases with age in boys but girls who are 12 years old or older, were not improved any mere. The patterns of running were same in both sexes, and maximum speed reached at about 30 meters from starting line. 6) The motor function was increased with age in both sexes, but there was no improvement in 12 years of age or older girls. More over records of all functions except standing broad jump was less than those of Japanese in the same age, respectively. 7) The maximum oxygen intake (MOI) was increased considerably with ages and maximum values were 2.93 L/min (boys) and 2.09 L/min (girls) at the age of 17years. This result was almost same as that of the Japanese and Easter Island population, but the value was lower than that of Europe. The average of the maximum oxygen intake per kg body weight per minute from 9 to 17 years of age were around 53 ml in the boys and 42 ml in the girls. 8) Muscle power was increased linearly with ages in boys while there was relatively a little increment in girls. The maximum values of leg muscle in boys and girls at the 17 years of age were 0.168 and 0.088 horse power, respectively. 9) The maximum endurance running time was increased considerably from the age of 9 in boys, while there was no improvement in girls. The maximum values were 6.0 min and 1.8 min, respectively.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.2
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• pp.231-242
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• 2014

It is throwing the spotlight on the cultivation crops about high quality crops and productivity improvement per unit area because of rapid climate change caused by global warming. Therefore, we propose a water culture management of circulation nutrient method control system applies to solar tracking method not using traditional method of deep flow technique and artificial light source. We design it in the form of the circulation nutrient method in waterway of a certain amount of nutrient solution and water flowed into the way of circular. In addition, we design a multistage structure in pyramid shape which be possible continuous photosynthesis action to crops of water culture bottom part. Also, solar tracking method is designed five sensor method of center hole sensor method for tracking shadow of solar light not using traditional two hole, four hole sensor method. Finally, through the water culture device applies to solar light tracking method was not introduced in existing study yet, we can reduce growth speed of crops which be possible continuous photosynthesis action to crops. Moreover, We can expect high productivity of per unit area which be possible all crops can be offered growth environment of same type by using form of pyramid shape of multistage structure without top or bottom part.