• Korean Journal of Applied Biomechanics
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• v.23 no.2
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• pp.109-116
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• 2013

The purpose of this study was to provide fundamental information for the enhancement of performance through kinematic analysis of cornering according to the radius of curve course in short track speed skating. To perform this study, six skaters: three narrow radius players(N, body mass: $56.0{\pm}7.2$ kg, height: $163.7{\pm}5.1$ cm, age: $21.3{\pm}1.5$ yrs) and three wide radius players(W, body mass: $61.0{\pm}9.5$ kg, height: $169.0{\pm}4.4$ cm, age: $20.0{\pm}1.7$ yrs). Three-dimensional motion analysis was performed on the section from the forth block starting to show the change of radius to the sixth block using eight infrared cameras(sampling frequency of 100 Hz for N and W players). The time of push-off was greater for N than for W(p<.05) while the radius of center of mass was greater for W than for N(p<.05). The flexion and extension of knee and hip joint were greater for N than for W(p<.05). The external rotation of left knee joint was greater for N than for W(p<.05). Based on the findings, a small radius by increasing the range of the flexion and extension of knee and hip joint with greater external rotation of left knee joint would be related to more efficient run at curve. It is expected that these results will be useful in developing a training program for enhancing performance of short track speed skating athletes.

• Advances in concrete construction
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• v.11 no.5
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• pp.429-445
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• 2021

With regard to economic efficiency, composite fix beams are widely used to pass longitudinal shear forces across the interface. The current knowledge of the composite beam load-slip activity and shear capability are restricted to data from measurements of push-off. Modelling and analysis of the composite beams based on Euro-code 4 regarding to shear, bending, and deflection under differing loads were carried out using Finite Element through an efficient computer simulation and the final loading and sections capacity based on the failure modes was analysed. In bending, the section potential was increased by an improvement of the strength in both steel and concrete, but the flexural and compressive resistance growth is very weak (3.2% 3.1% and 3.0%), while the strength of the concrete has increased respectively from 25 N/mm² to 30, 35, and 40 N/mm² compared to the increment of steel strength by 27% and 21% when it was raised from 275 to 355 and 460 N/mm², respectively. It was found that the final flexural load capacity of fix beams was declined with increase in the fix beam span for both three steel strength. The shear capacity of sections was remained unchanged at constant steel strength and different length, but raised with final yield strength increment of steel sections by 29%, and 67% when it was raised from 275 N/mm² to 355 N/mm² and 460 N/mm², respectively.

• Korean Journal of Applied Biomechanics
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• v.30 no.4
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• pp.321-335
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• 2020

Objective: The purpose of this study was to investigate the effect of neck traction and foot type on plantar pressure distribution during walking. Method: Total of 24 data were collected from women working with a computer for more than 6 hours every day. Three groups by foot type were divided: Pes Planus, normal foot, and Pes Cavus. Depending on the foot type and cervical traction, plantar pressure variables were measured; CA, MF, PP, and CT. Each variable was divided into 12 masks. MANOVA was performed for the difference of plantar pressure variables by foot type, and a paired t-test was performed for the cervical traction within groups. Results: The total CA decreased in the Pes Planus (p<.001) and Pes Cavus (p<.05) groups. MF increased in the big toe (p<.01) and 2nd toe (p<.05) of the normal foot, and MF-3rd metatarsal decreased (p<.01). The MF-2nd toe (p<.01) and 3rd toe (p<.05) of Pes Cavus decreased. The PP decreased in 2nd toe (p<.05), 3rd toe (p<.01), and 4th toe (p<.05) of the Pes Cavus. In normal foot, the PP-3rd metatarsal (p<.05) and PP-4th metatarsal (p<.01) reduced. In Pes Planus, PP decreased in the hindfoot (p<.05). In Pes Cavus group wearing a neck-tractor, the CT-hindfoot increased (p<.05). Conclusion: There was a significant change in the plantar pressure change by foot type after neck traction. When walking with a neck-tractor, the heel impact was alleviated in the Pes Planus, and the Pes Cavus showed the smooth and effective propulsion in the push-off. Overall, weight acceptance was effectively performed when walking with neck-traction. It was also found that the neck-tractor corrects the alignment of the neck, thereby creating a more stable gait pattern.

• Korean Journal of Applied Biomechanics
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• v.16 no.3
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• pp.105-115
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• 2006

The purpose of this study is to elucidate the mechanical characteristics of lower extremity joint movements at different walking speeds in obese people and suggest the very suitable exercise for obese person's own body weight and basic data for clinical application leading to medical treatment of obesity. This experimental subjects are all males between the ages of 20 and 30, who are classified into two groups according to Body Mass Index(BMI): one group is 15 people with normal body weight and the other 15 obese people. Walking speed is analysed at 3 different speeds ($1.5^m/s$, $1.8^m/s$, $2.1^m/s$) which is increased by $0.3^m/s$ from the standard speed of $1.5^m/s$. We calculated joint moments of lower extremity during stance phase through video recording and platform force measurement.Two-way ANOVA(Analysis of Variance, Mix) is applied to get the difference of moments according to walking speeds between normal and obese groups. Pearson's Correlation Analysis is applied to look into correlation between walking speeds and joint moments in both groups. Significance level of each experiment is set as ${\alpha}=.05$. As walking speed increases maximum ankle plantar flexion moment in the stance phase is smaller in obese group than in normal group, which is suggestive of weak toe push-off during terminal stance in obese group, and the highest maximum ankle plantar flexion moment in obese group during the middle speed walking($1.8^m/s.$). Maximum ankle dorsal flexion moment in obese group is relatively higher than in normal group and this is regarded as a kind of compensatory mechanism to decrease the impact on ankle when heel contacts the floor. Maximum knee flexion and extension moments are both higher in normal group with an increase tendency proportional to walking speed and maximum hip flexion and extension moments higher in obese group. In summary, maximum ankle plantar flexion moment between groups(p<.025), maximum knee moment not in flexion but in extension(p<.001) within each group according to increasing walking speed, and maximum hip flexion and extension moment(p<.001 and p<.004, respectively according to increasing walking speed are statistically significant but knee and hip moments between groups are not. Pearson correlation are different: high correlation coefficients in maximum knee flexion and extension moments, in maximum hip extension moment but not hip flexion, and in maximum ankle dorsal flexion moment but not ankle plantar flexion, in each group. We suspect that equilibrium imbalance develops when the subject increases walking speed and the time is around which he takes his foot off the floor.

• Korean Journal of Applied Biomechanics
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• v.13 no.3
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• pp.81-98
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• 2003

The purpose of this study is to closely examine kinematic characteristics by jump phase of Li Xiaopeng motion in horse vaulting and provide the training data. In doing so, as a result of analyzing kinematic variables through 3-dimensional cinematographic using the high-speed video camera to Li Xiaopeng motion first performed at the men's vault competition at the 14th Busan Asian Games, the following conclusion was obtained. 1. It was indicated that at the post-flight, the increase of flight time and height and twisting rotational velocity has a decisive effect on the increase of twist displacement. And Li Xiaopeng motion showed longer flight time and higher flight height than Ropez motion with the same twist displacement of entire movement. Also the rotational displacement of the trunk at peak of COG was much short of $360^{\circ}$(one rotation) but twist displacement showed $606^{\circ}$. Likewise, Li Xiaopeng motion was indicated to concentrate on twist movement in the early flight. 2. It was indicated that at the landing, Li Xiaopeng motion gets the hip to move back, the trunk to stand up and the horizontal velocity of COG to slow down. This is thought to be the performance of sufficient landing, resulting from large security of rotational displacement of airborne and twist displacement. 3. It was indicated that at the board contact, Li Xiaopeng motion made a rapid rotation uprighting the trunk to recover slowing velocity caused by jumping with the horse in the back, and has already twisted the trunk nearly close to $40^{\circ}$ at board contact. Under the premise that elasticity is generated without the change of the feet contacting the board, it will give an aid to the rotation and twist of pre-flight. Thus, in the round-oH phase, the tap of waist according to the fraction and extension of hip joint and arm push is thought to be very important. 4. It was indicated that at the pre-flight, Li Xiaopeng motion showed bigger movement than the techniques of precedented studies rushing to the horse, and overcomes the concern of relatively low power of jump through the rapid rotation of the trunk. Li Xiaopeng motion secured much twist distance, increased rotational distance with the trunk bent forward, resulting in the effect of rushing to the horse. 5. At horse contact, Li Xiaopeng motion makes a short-time contact, and maintains horse take-off angle close to vertical, contributing to the increase of post-flight time and height. This is thought to be resulted from rapid move toward movement direction along with the rotational velocity of trunk rapidly earned prior to horse contact, and little shave of rotation axis according to twist motion because of effective twist in the same direction.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.1
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• pp.133-143
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• 2002

The textile industry is petting increased effort to manufacture the value-added products that gives the differentiated characters at every level of fiber and fabric production. The color is an important element to be used strategically in order to push up the value-added design. The colors of apparel products have a close relationship with the skin colors of consumers and their preference colors. This study was carried out to cluster the skin colors of the Korean women into several similar skin colors and to analyze their preference colors by the classified groups. We measured the skin colors of 354 Korean women. With color spectrometer, JX-777, we measured 4 points of the body; cheek with removing cosmetics off, forehead, rear neck and arm on the interior part near elbow. All subjects had been shown with 40 color chips and answered the preference colors and preference colors of apparel. Data were analysed to classify skin colors using K-means Cluster Analysis and Duncan test, Frequency and Chi square test on the preference colors about the clustered 3 groups. In doing so, we used in SPSS Win 10 statistical package. Findings were as fellows: 1) The skin colors of the Korean women were clustered into YR, R, and Y skin colors. The majority of the subjects, 324 observations had YR skin colors and the subjects were classified into 3 kinds of skin color groups who had YR skin colors. 2) The average skin colors of total 324 subjects was 5.23YR 6.49/4.09 in Munsell Color System(MCS), 66.56 in L value, 10.53 in a value, and 20.67 in b value. 3) The average skin color of Type 1 was 7.98YR 6.24/4.14 in MCS, 64.10 in L value, 15.05 in a value, and 24.0 in b value. For Type 2 was 7.30 YR 6.56/3.28 in MCS, 67.24 in L value, 6.89 in a value, and 18.4 in b value, and Type 3 was 7.01 YR 7.20/4.38 in MCS, 73.53 in L value, L 16.04 in a value, and 24.87 in b value. 4) The average face color of total 324 subjects was 7.31YR 6.65/3.56 in MCS, 68.13 in L value, 9.53 in a value, and 20.18 in b value. 5) The average face color of Type 1 was 4.19 YR 6.92/5.05 in MCS, 70.78 in L value, 13.2 in a value, and 25.32 in b value. For Type 2 was 5.24YR 6.33/3.79 in MCS, 64.94 in L value, 9.84 in a value, and 19.08 in b value. Type 3 was 5.4YR 6.85/4.68 in MCS, 70.1 in L value, 11.73 in a value, and 23.92 in b value. 6) The difference of mean values between the clustered 3 skin color groups showed significantly different except the a value of neck and H value of cheeks and H value of foreheads. 7) All 3 groups showed that the most preference colors and the most preference colors of apparel was 5R 4/14. and their preference colors were much more than the preference colors of apparel.

• The Journal of the Korean bone and joint tumor society
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• v.18 no.2
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• pp.51-58
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• 2012

Purpose: This study attempts to know functional results and gait analysis usefulness in patients with bone tumor around knee joint tumors who underwent prosthesis knee joint reconstruction. Materials and Methods: Retrospective study was conducted with 7 patients out of 30 patients who underwent prosthesis knee joint reconstruction after wide marginal excision for bone tumor around knee in orthopedics of this hospital from 2001 to 2010. Functional assessment and gait analysis were perforemed. Results: For the SF-36 score, while 'role physical' and 'role emotional' items showed 100% (100 points) high scores individually, general health, physical function, vitality, and social function showed low scores. The mean score of MSTS was 88.1% (23.8 points [17-27]), indicating a relatively high score. For the gait analysis, mean gait velocity was 97.2 m/s, mean cadence was 105.6 step/min, mean stride length was 111.3 m, mean step length was 61.5 cm, swing phase was 39.8%cycle, stance phase was 60.1%cycle, mean single limb support was 37.1%cycle, mean double limb support was 13.0%cycle, and mean push off was 60.7%cycle. Conclusion: It is expected that prosthesis reconstruction after wide marginal excision for bone tumor around knee has relatively good functional results. Gait analysis was considered one of method which showed gait phase and assessed functional ability objectively by quantitative assessment post operative patient condition. It might help treatment and post operative rehabilitation planning with the functional assessment.

• Journal of the Korea Concrete Institute
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• v.28 no.2
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• pp.167-176
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• 2016

Shear friction strength model of concrete was proposed to explain the direct friction mechanism at the concrete interfaces intersecting two structural elements. The model was derived from a mechanism analysis based on the upper-bound theorem of concrete plasticity considering the effect of transverse reinforcement and applied axial loads on the shear strength at concrete interfaces. Concrete was modelled as a rigid-perfectly plastic material obeying modified Coulomb failure criteria. To allow the influence of concrete type and maximum aggregate size on the effectiveness strength of concrete, the stress-strain models proposed by Yang et al. and Hordijk were employed in compression and tension, respectively. From the conversion of these stress-strain models into rigidly perfect materials, the effectiveness factor for compression, ratio of effective tensile strength to compressive strength and angle of concrete friction were then mathematically generalized. The proposed shear friction strength model was compared with 91 push-off specimens compiled from the available literature. Unlike the existing equations or code equations, the proposed model possessed an application of diversity against various parameters. As a result, the mean and standard deviation of the ratios between experiments and predictions using the present model are 0.95 and 0.15, respectively, indicating a better accuracy and less variation than the other equations, regardless of concrete type, the amount of transverse reinforcement, and the magnitude of applied axial stresses.

• The Korean Journal of Air & Space Law and Policy
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• v.35 no.1
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• pp.153-180
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• 2020

This study is meaningful in finding out what legal and policy issues need to be improved in order to foster the aircraft industry, which is relatively underdeveloped compared to the fact that some heavy industries, such as the automobile industry and shipbuilding industry, have achieved a high level of production and technology globally. Korea's aircraft industry has been growing at a slower pace than other industries, largely due to the country's economic growth and the lack of a market structure to properly use variables such as the level of development in related industries, aircraft technology and demand for aircraft manufacturing. While most industries are privately led by the market structure of the competition system, heavy industries such as the aircraft industry generally grow under the market structure of the incomplete competition system, because only by securing huge initial investment costs, high technology, and sufficient demand, they can maintain minimum economic feasibility. The Korean aircraft industry was focused on developing and mass-producing military aircraft focusing on military demand, but it sought to turn the tide by signing the BASA (Bileral Aviation Safety Agreement) with the U.S. A preliminary feasibility study was conducted in 2010 to develop next-generation medium-sized aircraft, but was cancelled due to differences in position with Canada's Bombardier, which is subject to the concourse, and Korea Aerospace Industries (KAI) is pushing for the production of Bombardier's Q400 license on its own. Compared to the mid-to-large sized civil aircraft that are facing difficulties in development, KAI and KARI are successfully developing technologies to unmanned aerial vehicles and civil helicopters. In addition, the unmanned aerial vehicle sector is not yet suitable for manufacturers that have an exclusive global influence, so we believe that it is necessary to pursue government-led research and development projects with a focus on the areas of commercial helicopters and unmanned aerial vehicles in order to foster the aircraft industry in the future. In addition, since military aircraft such as KT-1 and T-50 are currently being exported smoothly, and it cannot be overlooked that the biggest demand for aircraft manufacturing in the Korea is the military, it is necessary to push forward national R&D projects and defense R&D program simultaneously to enable both civilian-military development. However, there are many differences between the two projects in the way they are implemented, the department in charge and the royalty system. Through this study, we learned about the technology ownership and implementation rights of national R&D projects and defense R&D programs, as well as the royalty system. In addition, problems with the system were identified and improvement measures were derived.

• (The) Research of the performance art and culture
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• no.37
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• pp.5-31
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• 2018

The mask dance drama Goseong Ogwangdae's first act, Mundung Bukchum. The story is about a man who was born to the upper class but contracted leprosy, an incurable disease, due to his ancestors' accumulated sin. Although he is suffering, he is able to triumph over the disease through sinmyeong (catharsis) that is expressed through the wordless act of Mundung Bukchum. This thesis focuses on Goseong Ogwangdae's Mundung Bukchum, particularly the meaning, costume, accompanying music, and process of pedagogical transmission. The chronological characteristics of Goseong Ogwangdae's Mundung Bukchum are as follows. First, as time goes on, the number of dance motions in Mundung Bukchum has increased and the motions used have become reified. Second, I address the small barrel drum used in Mundung Bukchum and check how, through the drum, the changed expression of Mundung is shown.In a 1965 video introduced Mundung is grasping the drum and stick and the dance appears to be made up only of humorous motions. Also in a 1969 video, "Mundung Gwangdae," from the start Mundung is grasping the drum and stick. In 1988 in a video we can see the same scene as today, with the drum and stick sitting in the center of the stage at the start of the dance. We can also confirm that the same fourteen dance motions used today are present. Third, we can also confirm the changes in Goseong Ogwangdae's signature motion, baegimsae as time goes on. Observing the video from 1965, baegimsae does not appear in Mundung Bukchum. In 2000 we can clearly see the baegimsae performed once to the left and to the right while Mundung is squatting. Comparing 1969 to 1988, there is no symmetry in the motions, baegimsae is not done to both left and right, but only in one direction. Watching the record from 2000, the baegimsae motion is performed just as it is now, with the body thrown forward with a sharp push off the ground. Fourth I confirmed how the music used to accompany Goseong Ogwangdae's Mundung Bukchum has changed over time. In 1965 according to records of Mundung Bukchum's appearance, the dance was accompanied by the taryeong rhythmic pattern played on the usual four percussion instruments (barrel drum, hourglass drum, large gong, small gong). In the 1969 records of Mundung Bukchum the accompanying music is gutgeori rhythmic pattern performed on the usual four percussion instruments-an obvious difference. In 1988 the music with Mundung Bukchum is gutgeori rhythmic pattern transitioning into jajinmori rhythmic pattern. In 2000 the music with Mundung Bukchum includes the percussion instruments as well as taepyeongso (double reed oboe) playing gutgeori and jajinmori rhythmic patterns.