• Structural Engineering and Mechanics
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• 제56권4호
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• pp.667-694
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• 2015

The suspended dome system is a new structural form that has become popular in the construction of long-span roof structures. Suspended dome is a kind of new pre-stressed space grid structure that has complex mechanical characteristics. In this paper, an optimum topology design algorithm is performed using the enhanced colliding bodies optimization (ECBO) method. The length of the strut, the cable initial strain, the cross-sectional area of the cables and the cross-sectional size of steel elements are adopted as design variables and the minimum volume of each dome is taken as the objective function. The topology optimization on lamella dome is performed by considering the type of the joint connections to determine the optimum number of rings, the optimum number of joints in each ring, the optimum height of crown and tubular sections of these domes. A simple procedure is provided to determine the configuration of the dome. This procedure includes calculating the joint coordinates and steel elements and cables constructions. The design constraints are implemented according to the provision of LRFD-AISC (Load and Resistance Factor Design-American Institute of Steel Constitution). This paper explores the efficiency of lamella dome with pin-joint and rigid-joint connections and compares them to investigate the performance of these domes under wind (according to the ASCE 7-05), dead and snow loading conditions. Then, a suspended dome with pin-joint single-layer reticulated shell and a suspended dome with rigid-joint single-layer reticulated shell are discussed. Optimization is performed via ECBO algorithm to demonstrate the effectiveness and robustness of the ECBO in creating optimal design for suspended domes.

• 한국콘텐츠학회논문지
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• 제10권2호
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• pp.268-276
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• 2010

본 연구의 목적은 경사로를 오르는 동안 슬관절 굴곡각도와 족저압의 차이를 각각 다른 경사도에 따라 분석하고자 하는 것이다. 24명의 건강한 성인 참가자들에게 각각의 경사도($0^{\circ},\;3^{\circ},\;6{\circ},\;9^{\circ}$)를 걷게 한 후, Parotec system을 이용하여 족저압을 측정하였으며, 걷는 모습을 캠코더로 녹화 한 후 Dartfish system을 이용하여 슬관절 각도를 분석하였으며, 수집된 데이터는 SPSS/PC 통계 프로그램을 이용하여 일원배치분산분석으로 분석하였다. 결과는 각 경사로에 따라 슬관절 굴곡 각도는 통계학적으로 유의한 차이가 나타났으며, 족저압은 좌측 하지의 발뒤꿈치 외측 부위(1번 감지기), 중족부 내측 부위(9번 감지기), 전족부 내측 부위(15번, 16번 감지기), 그리고 우측 하지에서는 발뒤꿈치 외측 부위(3번 감지기)에서 통계학적으로 유의한 차이를 보였다. 슬관절 각도가 $10{\sim}20^{\circ}$ 사이에서 발뒤꿈치 외측 부위 및 내측 부위의 족저압이 통계학적으로 유의하게 높게 나타났다.

• 한국철도학회논문집
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• 제13권5호
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• pp.521-527
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• 2010

포장궤도는 토공구간, 교량구간, 터널구간, 분기기구간 등 모든 구간에서 유지보수를 절감할 목적으로 적용한다. 토공구간에 포장궤도를 적용할 경우, 내구성에 가장 큰 영향을 미치는 것은 시공이음매부로서 구조적인 문제는 없으나 슬래브의 불연속으로 인한 단차가 발생하여 장기적인 사용성에 영향을 미칠 가능성이 있다. 따라서 이에 대한 검토를 위하여 실물의 포장궤도를 제작하여 시공이음매부와 연속부에서 가속실험을 실시하였다. 가속실험에서는 각 재하하중별 변위와 토압에 대한 경향을 비교함으로써 시공이음매부에서의 취약도를 평가하고자 하였다.

• 터널과지하공간
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• 제24권1호
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• pp.55-66
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• 2014

본 연구에서는 절리구조의 기하학적 특성을 분석하기 위해 사진측량기법을 효율적으로 현장에 적용하기 위한 절리조사 시스템을 개발하였다. 개발된 시스템은 하드웨어와 해석 소프트웨어로 구성된다. 하드웨어는 암반 절리구조의 영상촬영을 위한 영상 촬영 시스템, 카메라의 촬영방향과 높이를 제어하는 촬영방향 제어 시스템, 그리고 카메라 매개변수 중 회전각 성분을 측정하기 위한 디지털 컴퍼스로 구성되었다. 해석 소프트웨어는 사진촬영을 통해 얻어진 이미지 자료로부터 절리의 방향성, 밀도 및 평균 길이를 분석하기 위해 개발하였으며 JointeXtractor로 명명하였다. 개발된 시스템을 암반 상부와 수목이나 낙석방지 울타리의 설치로 인해 접근이 어려운 지역 등 수작업 조사자가 측정할 수 없는 경우의 현장에 적용한 결과 절리의 방향성 및 밀도, 평균 길이를 정량적으로 분석할 수 있었다.

• Journal of Welding and Joining
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• 제17권3호
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• pp.79-89
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• 1999

The study was carried out to examine in more detail metallurgical and mechanical properties of brazed joints of diamond cutting wheel. In this work, shank(mild steel) and sintered bronze-base tips were brazed with three different filler materials(W-40, BAgl and BAg3S). The machine used in this work was a high frequency induction brazing equipment. The joint thickness, porosities and microstructure of brazed joints with brazing variables(brazing temperature, holding time) were evaluated with OLM, SEM, EDS and XRD. Bending(torque) test was also performed to evaluate strength of brazed joints. Further wetting test was performed in a vacuum furnace in order to evaluate the wettability of filler metals on base metals9shank and tips). The brazing temperature had a strong influence on the joint strength and the optimum brazing temperature range was about $700~850^{\circ}C$ for the bronze/steel combinations. The strength of the brazed joint was found to be influenced by the three factors : degree of reaction region, porosity content, joint thickness. The reaction region was formed in the bronze-base tip adjacent to the joint. The reaction region resulted in a bad influence on the strength due to the formation of Cu5.6Sn, CuZn4, $\beta(CuZn)$ and CdAg, etc. Porosities increased as brazing variables(brazing temperature, holding time) increased, and the brazed joints with porosities of less than about 3-5% had an optimum strength for the bronze-base tip.

• Journal of Biosystems Engineering
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• 제40권3호
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• pp.289-295
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• 2015

Purpose: From the perspective of biomechanics, joint moments quantitatively show a subject's ability to perform actions. In this study, the effect of normalization in the fast and asymmetric motions of a golf swing was investigated by applying three different normalization methods to the raw joint moment. Methods: The study included 13 subjects with no previous history of musculoskeletal diseases. Golf swing analyses were performed with six infrared cameras and two force plates. The majority of the raw peak joint moments showed a significant correlation at p < 0.05. Additionally, the resulting effects after applying body weight (BW), body weight multiplied by height (BWH), and body weight multiplied by leg length (BWL) normalization methods were analyzed through correlation and regression analysis. Results: The BW, BWH, and BWL normalization methods normalized 8, 10, and 11 peak joint moments out of 18, respectively. The best method for normalizing the golf swing was found to be the BWL method, which showed significant statistical differences. Several raw peak joint moments showed no significant correlation with measured anthropometrics, which was considered to be related to the muscle coordination that occurs in the swing of skilled professional golfers. Conclusions: The results of this study show that the BWL normalization method can effectively remove differences due to physical characteristics in the golf swing analysis.

• 대한의용생체공학회:의공학회지
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• 제24권3호
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• pp.209-215
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• 2003

본 연구에서는 지면반발력에 저항하는 족부관절의 기구학적 특성과 운동학적 특성 사이의 관계를 고찰하는 것을 목적으로 하였다. 관절의 수동탄성모멘트와 각변위는 3대의 카메라와 지면반발력 측정기를 이용한 실험을 통하여 얻어졌다. 최소자승법을 이용하여 관절의 각변위와 모멘트의 상관 관계를 수학적으로 모델링 하였다. 관절의 운동 범위(range of motion)는 중족지절관절(metatarsophalangeal joint)을 제외하고는 5$^{\circ}$~7$^{\circ}$ 값을 보였다. 이 모델을 이용하여 지금까지 일반적인 모션 분석으로부터 측정할 수 없었던 족부관절의 기구학적 데이터를 얻을 수 있다. 더 나아가 이러한 수학적은 보행을 시뮬레이션 하는 생체 역학적 모델과 임상적 평가에도 적용 가능하다.

• 사상체질의학회지
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• 제19권2호
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• pp.195-203
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• 2007

1. Objectives The purpose of this study is to evaluate the effects of Gihwangbaekho-tang which is based on the Sasang Constitutional Medicine for the patient who has suffered from hip joint pain. 2. Methods The subject is about 86-year-old patient suffering from hip joint pain who was diagnosed as Soyangin interior over heated disease based on his Nature & Emotion, physical characteristics, symptoms, and we have prescribed Gihwangbaekho-tang. We used Visual analogue scale(VAS) for the assessment of Hip joint pain. 3. Results and Conclusions The patient was treated with Gihwangbaekho-tang and hip joint pain, thirst, redness of the face, constipation and general condition were improved. This study describes tile improvement of Hip joint pain and the change of symptoms by using Gihwangbaekho-tang. In this study, we applied Gihwangbaekho-tang to 86-year-old patient for about forty days, and Gihwangbaekho-tang didn't cause any serious side effect on the patient.

• 대한물리치료과학회지
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• 제1권2호
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• pp.289-299
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• 1994

This study was researched the general characteristics, the elbow-knee joint form, the varus and valgus angle and the both knee joint distance of the 215 persons form July 1, 1994 to July 15, 1994. The results were as follows : 1. The form of elbow joint was significant statistically in the sex group(p<0.05). 2. The angle of elbow joint was very significant statistically in the age group and sex. B.M.I. group(p<0.001, p<0.01, p<0.01), and the average angle was $9^{\circ}.51{\pm}4^{\circ}.79$(n=215). 3. The angle of Cubitus valgus was very significant statistically in the age group(p<0.001), and the average angle of Cubitus valgus was $10^{\circ}.85{\pm}3^{\circ}.76$(n=187). 4. The angle of Knee joint was significant statistically in the age group(p<0.05), and the its average angle was $7^{\circ}.63{\pm}4^{\circ}.52$(n=215). 5. The angle of Genu varus was significant statistically in the age and sex group(p<0.05, p<0.05), and the its average was $6^{\circ}.92{\pm}2^{\circ}.36$(n=27). 6. The angle of Genu valgus was very significant statistically in the age group(p<0.001), and the its average angle was $9^{\circ}.75{\pm}2^{\circ}.94$(n=149). 7. The distance of both Knee joint was significant statistically in the age group and B. M. I. group (p<0.001, p<0.05), and the its average distance was $2.55{\pm}1.45cm$(n=135).

• 대한조선학회논문집
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• 제38권3호
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• pp.93-106
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• 2001

선체 구조에서 피로 손상을 받기 쉬운 용접 부위인 T형 이음부(T-joint) 및 호퍼 너클 이음부(hopper knuckle joint) 모델의 피로실험 및 선형탄성 파괴역학을 이용한 피로균열 진전해석을 수행하였다. 집중 응력(hot spot stress)을 적용하여 정의된 균열 개시수명(균열 깊이 1mm)을 기준으로 하는 통합된 S-N선도를 작성하였으며, 잔류응력을 고려한 피로균열 진전해석을 통하여 피로균열 진전수명을 정확히 예측할 수 있었다. 또한, 임의의 형상을 가지는 용접 이음부(weld joint)의 피로균열 진전수명에 대한 정량화의 가능성을 확인하였다.