• 한국운동역학회지
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• 제15권2호
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• pp.185-196
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance and it is very important to know the patterns of plantar pressure distribution for the better understanding of forehand stroke. Therefore, the purpose of this study was to investigate the change of plantar pressure distribution according to close, square and open stance patterns during forehand stroke in tennis. Three high school tennis players were recruited for the study and required to perform forehand stroke five consecutive trials in the condition of open, square and close stance. The forehand strokes were filmed with two digital video cameras and measured with pedar system for plantar pressure. The plantar regions under the foot were divided into 3 regions, which were forefoot, midfoot, and rear foot.. In conclusion, the first hypothesis, "The plantar pressure of close stance during forehand stroke would be distributed more largely to the left foot.", was rejected and the result showed that The plantar pressure of close stance during forehand stroke was distributed transferring from right foot to left foot similar to square stance. The second hypothesis, "The plantar pressure of square stance during forehand stroke would be distributed transferring from right foot to left foot." was accepted. The third hypothesis, "The plantar pressure of open stance during forehand stroke would be distributed more largely to the right foot.", was accepted.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2008년도 정보통신설비 학술대회
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• pp.425-428
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• 2008

A new type of cross-coupled planar microwave filter using coupled microstrip square open-loop resonators diplexer pro-posed. A method for the rigorous calculation of the coupling coefficients of basic four pole electric and magnetic coupling structures encountered. Simple empirical models are derived for estimation of the coupling coefficients. Experiments are performed to verify the theory. And a method for diplexer matching is conjugate matching that has characteristic better than open matching method.

• 대한전자공학회논문지SD
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• 제46권3호
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• pp.20-25
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• 2009

본 논문에서는 모바일 환경 기반의 3차원 그래픽 연산을 위한 조명처리 엔진 및 쉐이더 프로세서에 사용 가능한 제곱근과 역제곱근 연산기의 구조를 제안한다. 제안하는 구조는 Taylor 전개식을 기반으로 하여 참조 테이블 및 보정 유닛으로 구성되어 있어 참조 테이블의 크기를 줄였다. 연산 결과는 IEEE-754 표준의 단정도 32 bit 부동소수점 형식과 모바일 환경을 위하여 이를 축소한 24 bit 부동소수점 형식에 대해 OpenGL 1.x ES 에서 요구하는 $10^{-5}$의 정확도를 거의 만족한다. 제안된 구조에 따라 설계된 제곱근 및 역제곱근 연산기는 Verilog-HDL을 사용하여 설계되었으며 파라미터 변경을 통하여 24 bit와 32 bit 연산이 가능하도록 합성이 가능하고 1사이클의 잠복기를 갖는다. 설계된 연산기들의 동작은 FPGA를 이용한 검증시스템을 통하여 검증하였다.

• 한국운동역학회지
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• 제17권1호
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• pp.53-60
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• 2007

Recently tennis techniques has been changed in stance patterns. Stance is consist of square stance, open stance and semi-open stance. The purpose of this study was to analyze the kinematics variables of racket head velocity during forehand stroke by stance patterns. Eight high school tennis players were chosen for the study who use semi western grip right-handed person more than career 7 years. They performed horizontal swing and vertical swing that it was done each five consecutive trial in the condition of square, open and semi-open stance. The results showed that racket head velocity significant difference was not observed in stance types between swings at impact. Y and Z components of racket head velocity for horizontal and vertical swing at second prior to impact and at impact were that y components velocity was faster horizontal swing than vertical swing and z components velocity was later horizontal swing than vertical swing. Statistically significant variable to racket head velocity and Pearson's correlation were drawn as follows. 1. Z components of racket head velocity in square stance was significant correlation by right knee joint. 2. Y components of racket head velocity in semiopen stance was significant correlation by left hip joint. 3. Y components of racket head velocity in open stance was significant correlation by left ankle joint.

• 한국주거학회논문집
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• 제7권1호
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• pp.37-47
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• 1996

The middle and high residences of the Chosun Dynasty in North Kyungbuk Area are based on $\square$-typed plans. It is supposed that their basic type is developed from more simple type. This study compares $\square$-type and more simple types, that is = and ㄷ and open-$\square$-type. Maybe, building process of $\square$-typed plan is similar to the spatial and constructional characteristics of incompleted $\square$-types, Their theoretical bases are described by the comparison of plan and space and structure and roof's construction.

• Steel and Composite Structures
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• 제21권2호
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• pp.411-427
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• 2016

While the cyclic behaviour of fiber-reinforced polymer (FRP)-confined columns is studied rather extensively, the cyclic response especially the energy dissipation of FRP-confined damaged and undamaged square RC columns is not yet fully understood. In this paper, an experimental and numerical investigation was conducted to study the cyclic behavior of two different types of Carbon FRP (CFRP)-confined square RC columns: strengthened and repaired. The main variables investigated are initial damage, confinement of CFRP, longitudinal steel reinforcement ratio. The experimental results show that lower initial damage, added confinement with CFRP and longitudinal reinforcement enhance the ductility, energy dissipation capacity and strength of the columns, decrease the stiffness and strength degradation rates of all CFRP-confined square RC columns. Two hysteretic constitutive models were developed for confined damaged and undamaged concrete and cast into the non-linear beam-column fiber-based models in the software Open System for Earthquake Engineering Simulation (OpenSees) to analyze the cyclic behavior of CFRP-confined damaged and undamaged columns. The results of the numerical models are in good agreement with the experiments.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 전력전자학술대회 논문집
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• pp.479-482
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• 2001

This paper proposes a modified $\alpha$ conduction mode for controlling the output voltage magnitude of three-phase square-wave VSIs with an R-L load. From the viewpoint of both power capacity and switching losses, three-phase square-wave inverters are now used in most high power systems. When the square-wave VSI is driven with $\alpha$ conduction mode to control the magnitude of output voltages, interval over than half period is operated with $180^{\circ}$ conduction mode and the other interval with $120^{\circ}$ conduction mode. In $120^{\circ}$ conduction mode operation, two output terminals are connected to DC supply and the third one remains open. The potential of this open terminal will depend on the load characteristics and is unpredictable except the case of pure resistive loads. To cope this problem, we propose the modified α conduction mode.

• 한국건축시공학회지
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• 제24권1호
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• pp.133-144
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• 2024

OpenCV 기반 길이측정 알고리즘은 길이측정 검측업무를 보조함과 동시에 객관적인 검측결과를 제시할 수 있을 것으로 판돤된다, 그러나, 건설현장 내에서 체커보드의 유형과 촬영조건이 해당 알고리즘의 정확도에 어떠한 영향을 미치는지에 대한 연구는 미흡한 실정이다. 이에 본 연구에서는 디지털 기술을 활용한 검측업무 수행에 적합한 체커보드와 촬영방법을 제시하고자 OpenCV 기반 길이측정 알고리즘 정확도 측정 실험을 수행하였다. 실험결과 OpenCV 기반 길이측정 알고리즘을 통한 검측업무 시 촬영거리 4m 이내, 촬영각도 90°의 조건 하, 체커보드 크기와 Square size를 각각 A4 이상, 50mm 이상으로 설정하는 것이 적절할 것으로 판단된다. 본 연구의 결과는 디지털 기술을 통한 길이측정 검측업무 수행 시 가이드라인으로 활용될 수 있을 것으로 사료된다.

• 한국화재소방학회논문지
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• 제9권1호
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• pp.10-19
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• 1995

Study on combined natural convection-radiation In partially open square enclosures filled with absorbing-anisotropic scattering media is performed. A heater block located in the enclosure causes the natural circulation of the fluid in the enclosure which results In significant in-flow of the cold fluid through the partially open wall. Four different locations of the heater are considered to observe the effect of the heater locations on the resulting heat transfer. Results obtained from the combined convection-radiation analyses show much stronger circulation of t he fluid inside the enclosure as compared to those obtained from the pure convection analyses. As the ratio of the open area is Increased, the inflow of the cold fluid and the circulation of the fluid inside the enclosure is increased causing lower fluid temperature Inside the enclosure. It is shown that the location of the heater influences the circulation and heat transfer significantly by showing stronger circulations and more uniform temperature distributions for the cases where the heater is located on the bottom wall as compared to those for the cases where the heater is located on the upper part wall of the enclosure. For pure absorbing medium, the expected circulation in the fluid is relatively week as compared to those with absorbing-scattering medium due to the smaller wall heating as the radiant heat is used to heat the fluid instead. The forward anisotropic scattering phase function is shown to increase the fluid circulation further as compared to the isotropic scattering medium.

• 한국운동역학회지
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• 제15권4호
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• pp.105-115
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance. The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to open, close, and square stance patterns during forehand stroke in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head angle were defined. In conclusion, the first hypothesis, "In three dimensional maximum linear velocity of racket head would be significant difference among the stance patterns during forehand stroke in tennis" was rejected. The second hypothesis, "In three dimensional anatomical angular displacement of trunk would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that the internal-external rotation showed most important role among the three dimensional anatomical angular displacement of trunk The third hypothesis, "In three dimensional anatomical angular displacement of upperlimb would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that The three dimensional anatomical angular displacement of shoulder joint showed most important role in forehand stroke. Flexion-extension and internal-external rotation the open stance showed the largest angular displacement and is follwed by square stance and closed stance. The fourth hypothesis, "In three dimensional anatomical angular velocity of upperlimb would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that X-axis angular velocity and Z-axis angular velocity the square stance showed the largest angular velocity of the trunk and X-axis angular velocity and Y-axis angular velocity the closed stance showed the largest angular velocity of the shoulder joint.