• Korean Journal of Applied Biomechanics
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• v.15 no.2
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• pp.11-20
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• 2005

This study has a purpose on contributing to apprehend safe and right way to stop to the inline skate beginners and to the instructors who teaches line skating on the basis for the result of the kinematical analysis on Heel brake stop movement of the inline skate, focusing on the displacement on COG, angle displacement of ankle joint, angle displacement of knee joint, angle displacement of hip joint, using a 3D image method by DLT. To achieve this goal, we analysed the kinematical factor of the 3 well-trained inline skating instructors and obtained the following results. 1. During the movement of heel-brake stop, when strong power was given to a stable and balanced stop and the lower limbs, if the physical centroid is lowered the stability increases, and if it is placed high from the base surface, as the stability decreases compared to the case of low physical centroid, we should make a stop by placing a physical centroid in the base surface and lowering the hight of physical centroid. 2. To make a stable and balanced stop and to provide a strong power to the lower limbs, it is advisable to make a stop by decreasing an angle displacement of ankle joint during a "down" movement. In case of the left ankle joint, in all events and phases the dorsiflexion angle showed a decrease. Nevertheless, in the case of the right ankle joint, the dorsiflexion angle shows an increase after a slight decrease. The dorsiflexion angle displacement of ankle joint can be diminished because of the brake pad of the rear axis frame of the right side inline skate by raising a toe, but cannot be more decreased if certain degree of an angle is made by a brake pad touching a ground surface. To provide a power to a brake pad, it is recommended to place a power by lowering a posture making the dorsiflexion angle of the left ankle joint relatively smaller than that of the right ankle. 3. To make a stable and balanced stop and to add a power to a brake pad, the power must be given to the lower limbs in lowering the hight of physical centroid. For this, it is recommended to make a down movement by decreasing the flexion angle of a knee joint and it is necessary to make a down movement by a regular decrease of the angle displacement of knee joint rather than a swift down movement in every event and phase. 4. The right angle displacement of hip joint is made by lowering vertically the hight of physical centroid as leaning slightly forward. If too narrow angle displacement of hip joint is made by leaning forward too much, the balance is lost during the stop by placing the center in front. To make a stable and balance stop and to place a strong power to the lower limbs, it is recommendable to make a narrow angle by lower the hip joint angle. However, excessive leaning of the upper body to make the angle too narrow, can cause an instable stop and loss of physical centroid. After this study, it is considered to assist the kinematical understanding during the heel brake stop movement of the inline skate, and, to present basic data in learning a method of stable and balanced stop for the inline skating beginners or for the inline skate instructors in the present situation of the complete absence of the study in inline skating.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2008.10a
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• pp.104-112
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• 2008

In modern war information system development makes battlefield materialize, and combat factors can maximize combat power exhibition as that apply synchronization. Information system is the core of combat power operation under NCW(Network centric Warfare). This paper proposed a new MOE(Measure of Effectiveness) that can assess the combat power synergistic effect of information system at the theater joint fire operation in NCW environment. This methodology applied the rule of Newton's second law $F=(m{\Delta}{\upsilon})/t{\Rightarrow}(M{\upsilon}I)/T$) Details factor in combat power evaluation is as following. (1) M : Network power; (2) v : Movement velocity; (3) I : Information superiority; (4) T : C2(command and control) time. We applied this methodology to the "JFOS-K(Joint Fire Operating System-Korea) in Joint Chief of Staff" in the real military affair section.

• Journal of Biomedical Engineering Research
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• v.45 no.2
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• pp.57-65
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• 2024

Recently, several studies have been conducted to lower the cost of transport of human by adding external joint stiffness elements. However, it has not been clearly elucidated whether adaptation time is required for human subjects to adapt to the added external joint stiffness. In this study, carbon plates in the form of shoe midsoles were added to the metatarsophalangeal joint, and the lower limb joint torque and mechanical energy consumption were compared before and after a total of 5 sessions (2.5 weeks) of running. A total of 11 young healthy participants exhibited higher elastic energy storage in carbon plates in the fifth session compared to the first session, and lower power in the ankle joint. This suggests that a single training session may be insufficient to validate the efficiency effect of added joint stiffness, and the human body seems to increase the elastic energy stored in the assistive joint stiffness and its reutilization.

• Journal of Digital Convergence
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• v.14 no.6
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• pp.513-518
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• 2016

The Mechanisms of whole body vibration on the human body is not clearly presented despite of the research result and there is not enough research that shows the effects of vibration on the kinetic changes of the lower joint. Therefore, this study focuses on finding out which lower joint is related with kinetic vertical jump ability. Five male and five female who didn't have orthopedic history were selected as the subjects. The subjects carried out three squat jumps before and after 5minutes of 30Hz whole body vibration. We have utilized a 3D motion analysis system to analyze the kinetic changes of the lower joint in the vertical jump. The height of subjects squat jump was improved after whole body vibration treatment. Also, the lower joint moment and power increased. However, there were no statistically significant changes in GRF, hip joint moment and power after the whole body vibration proved to have positive effect on the ankle and knee joints but showed negative effect on the hip joint.

• Korean Journal of Applied Biomechanics
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• v.29 no.4
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• pp.255-261
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• 2019

Objective: The purpose of this study was to investigate differences of shock attenuation strategies between double-leg and single-leg landing on sagittal plane using statistical parametric mapping. Method: Nine healthy female professional soccer players (age: 24.0±2.5 yrs, height: 164.9±3.3 cm, weight: 55.7±6.6 kg, career: 11.2±1.4 yrs) were participated in this study. The subjects performed 10 times of double-leg and single-leg landing from the box of 30 cm height onto force plates respectively. The ground reaction force, angle, moment, angular velocity, and power of the ankle, knee, and hip joint on sagittal plane was calculated from initial contact to maximum knee flexion during landing phase. Statistical parametric mapping was used to compare the biomechanical variables of double-leg and single-leg landing of the dominant leg throughout the landing phase. Each mean difference of variables was analyzed using a paired t-test and alpha level was set to 0.05. Results: For the biomechanical variables, significantly increased vertical ground reaction force, plantarflexion moment of the ankle joint, negative ankle joint power and extension moment of the hip joint were found in single-leg landing compared to double-leg landing (p<.05). In addition, the flexion angle and angular velocity of the knee and hip joint in double-leg landing were observed significantly greater than single-leg landing, respectively (p<.05). Conclusion: These findings suggested that negative joint power and plantarflexion moment of the ankle joint can contribute to shock absorption during single-leg landing and may be the factors for preventing the musculoskeletal injuries of the lower extremity by an external force.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.63 no.2
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• pp.113-118
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• 2014

Tidal power is one of new and renewable energy sources. Tidal power is generated by using the gap in the water level between the water outside and inside the embankment. All tidal power plant in Korea were being operated by import of turn-key from abroad. The know-how and technology which are the most important to build predictive control system has become increasingly difficult to obtain from advanced countries because most of them avoid to transfer, which the domestic development of the control system is needed. In this paper, a study on start stop system at water turbine-generator for tidal power plant at the beginning of development was presented. For improvement the efficiency and develope of core technology of the start stop system, the technique and characteristics of tidal power, modeling, maximum generation calculation method, and optimal control of joint control system in Sihwa tidal power plant were studied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.6
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• pp.2691-2697
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• 2011

The purpose of the dissertation is to offer basic data available for being conducive to application of a training program by comparatively analyzing the players' physical strength, the knee joint, a hip joint, power of the trunk joint and muscle power in order to study isokinetic strength and muscle power between short distance athletes and Taekwondo players. This study measured peak power, %Body weight peak power, always power, and %Body weight peak power targeting 8 male athletes and 8 male Taekwondo players who warmed up 10 minutes before from the test to reduce repulsion and unfamiliarity at the instrument. The power of the knee joint($60^{\circ}$/sec), muscle power($180^{\circ}$/sec), were measured by using HUNOM(U.S.A). As a result of the physical strength, statistically, short distance athletes were indicated to be better in muscle strength, muscular endurance than Taekwondo players, and there was no significant difference between flexibility, power, and muscular endurance. Although the short distance athletes were indicated to be better in right and left muscle strength of knee joint than Taekwondo player, there was no significant difference and Taekwonde players were indicated to be higher at the right and left muscle power than short distance athletes.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.765-766
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• 2012

• Korean Journal of Acupuncture
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• v.20 no.4
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• pp.85-98
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• 2003

Objective : This study is designed to find out the effects of Rainbow Power therapy on knee joint with osteoarthritis. Methods : Patient with the osteoarthritis of knee joints are divided into Rainbow Power therapy group(20 people) and none-Rainbow Power therapy group(20 people). After treatment, we evaluated the effect per each group. Results : 1. Fifty and Sixty aged patients were the most in the Rainbow Power group(30% each) and sixty aged patients were the most in the None-Rainbow Power group(45%). 2. In the both groups, 1-3 years duration of disease was the most(40%, 45% each). 3. In the none-Rainbow Power group, patients improved (Lysholm score : $49.20{\pm}11.54{\rightarrow}63.90{\pm}9.54$, p<0.05), but, did not improved in the part of squatting and dystrophy. In the Rainbow Power group, patients improved(Lysholm score : $46.55{\pm}9.89{\rightarrow}80.90{\pm}13.78$, p<0.05), but, did not improved only in the part of dystrophy. 4. The effects of treatment by VNRS were follow : After treatment, $4.10{\pm}1.22$ in Rainbow Power Group and $4.55{\pm}1.15$ in none-Rainbow Power group. 5. The effects of treatment by nine points scale were follow : In the Rainbow Power group, the Excellent was 7 cases(35%), the Good was 9 cases(45%), the Fair was 4 cases(20%) and there was no Poor. The Excellent was 6 cases(30%), the Good was 8 cases(40%), the Fair was 6 cases(30%) and there was no Poor.

• KEPCO Journal on Electric Power and Energy
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• v.1 no.1
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• pp.39-46
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• 2015

A outdoor termination installed at the outdoor substation is required to connect undergroud cables and overhead transmission lines. The joint box for AC transmission system is already developed and widely used to interconnect overhead and undergroud systems. But the development of the joint box for DC transmission system was only introduced from China and Japan, but theire developemnt staus and core technologies were not fully reported. In order to implement HVDC systems connecting ovehead transmission lines and undergroud cables, a outdoor termination should be developed, but the detailed specifications and information of this device were not reported. It is estimated that the development of the joint box for DC environment has some technical obstacles including insulating materials, electric field mitigation, thermal temperature rise, and space charge accumuations. Among this, the most important one is the DC elctrical insualtion design. Therefore, in order to investigate the DC elctrical insualton design of outdoor termination, the design of AC slip-on type outdoor termination is reffered, and DC electric field analysis performed to verify the possiblity of application of AC joint box into DC joint box. Especially for DC electric field analysis, temperature rise of insualting materials of a joint box was considered, because the conductivity of materials could be changed due to temperature rise. Furthermore, DC electric field analysis considering transinet state, and polarity reversal state were also investigated to verify which state is the most severe condition for the DC joint box. From the simualtion resulsts, it was shown that the value and the position of maximum electric field was obtained comparing AC state, DC state without temperaure rise, and DC state with temperaure rise. And it was confimred that severe DC electric field was observed considing temperaure rise. Finally, in order to reduce DC eletric field intensifation, different configuration of the joint box was applied and it was not possible to obtain satisfactory results. It means that the slight change of configuration of AC joint box was not the suitable soluton for DC joint box. It is essential to establish novel DC insulaton design skills and method for DC joint box to commercialze this product in the near future.