• 한국생산제조학회지
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• 제18권6호
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• pp.576-584
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• 2009

Up to now, it has been said that no satisfactory computer solution has been found for synthesizing four-bar linkage based on the prescribed coupler link curve. In our study, an algorithm has been developed to improve the design synthesis of four bar linkage based on the 5 precision points method. The suggested algorithm generates the desired coupler curve by using NURBS, and then the generated curve approximates as closely as possible to the desired curve representing coupler link trajectory. Also, when comparing each generated curve by constructing the control polygon, rapid comparison is easily achieved by applying convex hull of the control polygon. Finally, an optimization process using ADS is incorporated into the algorithm based on the 5 precision point method to reduce the total optimization process time. As for examples, two four bar linkages were tested and the result well demonstrated the effectiveness of the algorithm.

• 한국정밀공학회지
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• 제16권10호
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• pp.126-131
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• 1999

Up until now, it is said that no satisfactory computer solutions have been found for synthesizing four-bar linkage based on the prescribed coupler link curve. In our study, an algorithm has been developed to improve the design synthesis of four-bar linkage automatically generating prescribed path by using B-spline interpolation. The suggested algorithm generates the desired coupler curve by using B-spline interpolation, and hence the generated curve approximates as closely as to the desired curve representing coupler link trajectory. Also, when comparing each generated polygon with the control polygon, rapid comparison by applying convex hull concept. finally, optimization process using ADS is incorporated into the algorithm based on the 5 precision point method to reduce the total optimization process time. As for examples, three different four-bar linkages were tested and the results showed the effectiveness of the algorithm.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.339-340
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• 2013

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집B
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• pp.454-458
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• 2001

In this paper, contact between the coupler-roller and guide in elevator door mechanism is modeled and analyzed with DADS 3D program. The contact force of coupler-roller is an important factor for impact and noise reduction when doors of elevator are opened or closed. To minimize the maximum contact force, an optimal cam profile for the door guide is suggested. To find an optimal shape of the guide, several types of motion curve are tested with DADS contact module.

• 한국기계가공학회지
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• 제17권1호
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• pp.130-137
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• 2018

In long freight trains, there is a brake time delay in the neighboring freight cars that causes damage and fractures of couplers, especially the knuckle of them. If there is a problem for couplers in the cars, this could cause a derailment and lead to damage of human life and property damage. In this study, maximum forces on the couplers are studied when a long freight car brakes, with brake delay time and coupler gap. We have made a dynamic model of 50 freight cars and couplers, applying contact between couplers and a characteristic curve for expressing force and displacement of buffers with SIMPACK, a multi-body dynamics program. We use EN 14531-2 from the British Standards Institution, a standard of freight car brakes for the verification of the dynamic model. We also use a simplified method to analyze the dynamic model of 50 freight cars. With changing coupler gap and brake delay time, we do comparative analysis with AAR M-201 from the Association of American Railroads, a standard of AAR couplers. From this result, we find that the standard on fatigue limit is satisfied, such that the brake delay time is within 0.06 second if the coupler gap of the AAR coupler is within 20 millimeters.

• 한국광학회지
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• 제16권5호
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• pp.446-449
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• 2005

방향성 결합기의 각종 설계 구조변경에 대해 소멸비 특성의 변화를 직관적으로 예측하기 쉽지 않으므로 각 구조마다 매번 번거로운 특성 계산의 반복 작업이 수행되었다. 본 논문에서는 방향성 결합기의 설계구조 변수의 조절에 따른 소멸비 특성 변화를 체계적으로 계산하였고, 이 특성변화의 일반적인 경향을 파악하였다. 즉, 도파로 간격을 입력 도파로의 폭으로 규격화하면 이 변화 경향을 일반화하는 특성곡선을 얻을 수 있는 것으로 파악되었다. 이때, 정규화주파수 v와 도파간격비율 d가 큰 구조일수록 소멸비를 높일 수 있었고, d를 동일하게 유지한 여러 경우의 구조에 대해서는 v의 변화에 따른 소멸비 특성곡선이 일치하는 것을 보였다. 이러한 소멸비 특성의 일반화 경향은 높은 소멸비 특성을 유지하면서도 소자를 작게 설계하거나 파장분리기의 설계에 유용하게 활용될 수 있으므로 1310/1550 nm 파장 분리기의 설계와 제작에 적용하여 그 효용성을 확인하였다.

• 한국기계가공학회지
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• 제18권2호
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• pp.65-72
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• 2019

In long freight trains, there is a brake time delay in neighboring freight cars, which causes damage and fractures in the couplers, especially at their knuckle. A problem in the couplers of the cars can cause derailment and damages of human life and property. In this study, maximum forces on the couplers are studied when a long freight car brakes with the brake delay time and coupler gap. We make a dynamic model of 50 freight cars and couplers, applying contact between the couplers and a characteristic curve to express the force and displacement of the buffers using SIMPACK, which is a multi-body dynamics program. We use EN 14531-2, which is a standard of freight car brakes, to verify the dynamic model. Then, we compare the analyzed impact force with the coupler knuckle standard after applying the two carriages of a locomotive in the model based on the dispersed double head control system. The result shows that all coupler gap conditions satisfy the infinite lifetime of the material when the brake delay time is 0.1 second.

• Archives of Plastic Surgery
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• 제50권2호
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• pp.213-215
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• 2023

• 한국군사과학기술학회지
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• 제14권1호
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• pp.1-8
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• 2011

In this paper, dual-feed circularly polarized microstrip patch antenna for GPS L1, GPS L2, GLONASS L1 signal was fabricated by using stacked patch. It was fed by dual coaxial probe on the patch at 50ohm impedance, and was simulated to resonate at GPS L1, GPS L2, GLONASS L1. To realize characteristics of right hand circular polarization using dual-feed stacked patch antenna and hybrid coupler for $90^{\circ}$ phase difference. Output of hybrid coupler was contacted input of Low Noise Amplifier(LNA). The LNA using dual band pass filter was designed and fabricated. The measured results of the implemented antenna is VSWR < 1.5 : 1 and the gain of 32dB(Zenith) over at GPS L1, L2, GLONASS L1.

• 한국산학기술학회논문지
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• 제19권7호
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• pp.275-282
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• 2018

산악트램은 기존 산악 도로에 매립형 궤도를 설치하여 무가선으로 주행할 수 있는 친환경 교통 시스템으로서, 결빙시에도 운행할 수 있는 장점이 있으나, 산악 도로의 급곡선과 급경사 구간을 주행해야 하는 어려움이 따르게 된다. 본 연구에서는 산악트램이 도로에 설치된 급곡선 급경사 궤도를 주행할 때의 기술적인 문제를 정의하고, 이 문제를 해결하기 위한 대차와 차체 연결 구조의 설계 방안을 제시하였으며, 시작품 제작 및 성능 시험을 통해 설계 방안의 효용성을 입증하였다. 급곡선 구간에서 내외 레일의 주행거리 차이가 심하게 발생하여 주행이 곤란해질 수 있으므로 좌우 차륜이 별개의 속도로 회전하는 독립구동 차륜을 개발하여 적용하였다. 기존 2대차-1차체 차량에서 발생할 수 있는 곡선구간에서의 공격각 및 횡압 증가에 따른 탈선을 방지하기 위해 1대차-1차체 차량을 설계하여 실제 적용하였다. 독립 구동차륜과 1대차-1차체 구조의 시험 차량 시작품을 제작하였고, 소형 궤도에서 시험 운행을 실시하여 성능을 검증하였다. 산악트램이 곡선과 경사를 통과할 시에 차체 간에 발생하는 3방향 회전 대변형을 흡수하기 위해 연결기를 설계하여 축소 시작품을 제작하였으며, 작동 시험을 실시하여 성능을 검증하였다.