• 산업기술연구
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• 제26권A호
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• pp.129-137
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• 2006

In this research, we made a one and two-dimensional analysis of numerical data collected from the bend curvature of a bended river section. According to the result from the numerical analysis, the inflow ＆ output angle caused a water level deviation which increased with an increase of the flood discharge. From the water level deviation of our two-dimensional numerical model, we obtained the maximum slope of 6,67% when the inflow and output angle was 105 degrees and the flood discharge was 500 CMS. As for the right side, the differences with the one-dimensional numerical model were reduced when the angle was more than $90^{\circ}$. As for the left side the differences were reduced when the angle was more than $105^{\circ}$. For a river with more than 90 degrees bend curvature, a hydraulic experiment would be more appropriate than a numerical analysis.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 D
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• pp.2457-2459
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• 2002

In this paper, we describe the way how to create a curvature trajectory where the dynamics of a mobile robot is considered. Synchro-drive motor is used in a mobile robot. And translational and rotational speeds are controlled independently. Using these two speeds, a mobile robot traces a smooth curvature trajectory that consists of circle trajectories to a target point. While trying to avoid obstacles, the robot can be goal-directed using curvature trajectory. Also, while the robot can navigate the trajectory, the maximum speed is controlled to trade off speed and safely.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1994년도 춘계학술대회 논문집
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• pp.34-37
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• 1994

.In this study, we measured Ic depending on a curvature radios of High Tc superconducting tapes which were made of a single wire, two and three WIT(wire in tube). Wires are manufactured by the process of press ins and sintering (150h, at 845$^{\circ}C$ ) for the growth of 2223 high Tc Bi superconducting phase. We know that Ic of a single wire decrease with reduction of a curvature radius. The maximum Ic of 2 WIT wire is 2.54 (A) and have a better characteristic than a single wire (0.89 A) at a curvature radius 75mm.

• 대한전자공학회논문지SP
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• 제40권6호
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• pp.114-123
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• 2003

본 논문에서는 다각형 기반 윤곽선 부호화를 위한 새로운 정점 선택 기법을 제안한다. 객체의 모양을 효율적으로 표현하기 위해서 정점 선택 과정에서 기존의 최대 거리 척도뿐만 아니라 곡률 정보를 이용한다. 제안된 기법은 두 단계 과정으로 구성되어 있다. 첫 번째 단계에서는 곡률이 큰 윤곽선 화소들을 CSS (curvature scale space)를 이용하여 키 정점(key vortices)으로 선택한다. 이 점들은 객체의 윤곽선을 여러 개의 부분 윤곽선(contour segment)들로 나누며, 각 부분 윤곽선은 양 끝점이 인접한 두 개의 키 정점인 하나의 열린 윤곽선으로 독립적으로 처리된다. 두 번째 단계에서는 각각의 부분 윤곽선에서 주어진 허용 오차(D/sub max//sup */)를 만족하면서 최소 개수의 정점을 선택하기 위해 순차적 정점 선택 기법을 이용하여 정점을 선택한다. 그리고 선택된 정점들은 오차 영역 면에서 최적의 위치를 찾기 위해 동적 프로그래밍(DP : dynamic programming) 기법을 사용하여 조정된다. 제안된 기법과 기존의 기법들의 근사 성능을 비교하기 위해 실험 결과를 제시한다.

• Imaging Science in Dentistry
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• 제45권4호
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• pp.221-226
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• 2015

Purpose: This study evaluated the prevalence of distolingual roots in mandibular molars among Koreans, the root canal system associated with distolingual roots, and the concurrent appearance of a distolingual root in the mandibular first molar and a C-shaped canal in the mandibular second molar. Materials and Methods: Cone-beam computed tomographic images of 264 patients were screened and examined. Axial sections of 1056 mandibular molars were evaluated to determine the number of roots. The interorifice distances from the distolingual canal to the distobuccal canal were also estimated. Using an image analysis program, the root canal curvature was calculated. Pearson's chi-square test, the paired t-test, one-way analysis of variance, and post-hoc analysis were performed. Results: Distolingual roots were observed in 26.1% of the subjects. In cases where a distolingual root was observed in the mandibular molar, a significant difference was observed in the root canal curvature between the buccolingual and mesiodistal orientations. The maximum root canal curvature was most commonly observed in the mesiodistal orientation in the coronal portion, but in the apical portion, maximum root canal curvature was most often observed in the buccolingual orientation. Conclusion: The canal curvature of distolingual roots was found to be very complex, with a different direction in each portion. No correlation was found between the presence of a distolingual root in the mandibular first molar and the presence of a C-shaped canal in the mandibular second molar.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.819-820
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• 2010

• 한방재활의학과학회지
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• 제27권1호
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• pp.37-51
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• 2017

Objectives This study was designed to identify the effect of acupuncture combined with wooden neck pillow self-exercise program (WSP). Methods 25 eligible subjects with chronic neck pain were recruited from September 2015 to August 2016. Subjects were treated by acupuncture twice a week for 4 weeks, also were educated WSP and exercised every day for 4 weeks. They were assessed using PI-NRS, NDI and the maximum muscle strength of deep cervical flexor muscles (DCF) before and after treatment. Also the Cobb's angle (C1-C7), Ishihara index, Park method were assessed for evaluating the radiographical changes. Variables were compared using paired t-test. And correlates analysis was used for analyzing relationship between differentials in the maximum muscle strength of DCF and differentials in cervical spine curvature measurement methods. Results Among the 25 subjects, 4 subjects were lost to follow-up or excluded in accordance with the criteria. Significant differences on NRS, NDI and the maximum muscle strength of DCF were seen after treatment (p<0.001). In radiological finding, cervical spine curvature measurement methods were significantly increased (p<0.001, p<0.05, p<0.05). Differentials in the maximum muscle strength of DCF significantly correlates to differentials in Ishihara index (R=0.479, p<0.05). Conclusions Acupuncture combined with WSP may decrease neck pain intensity and associated disability, and also increase the muscle strength of DCF and cervical lordosis, in patients with chronic neck pain. Especially, Improving the muscle strength of DCF has a relationship with improving Ishihara index. However, due to the design of this study, this treatment can not be compared with other treatments. Future randomized project should be needed.

• 한국측량학회지
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• 제32권1호
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• pp.55-62
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• 2014

본 연구에서는 2011년 우면산 산사태 지역에 대한 현장조사를 수행하여 발생지점에 대한 자료를 구축하였으며, 산사태 발생 전후의 항공사진과 항공LiDAR DEM을 이용하여 여러 가지 지형인자들에 대한 단위면적당 발생빈도를 분석하였다. 경사도는 Neighborhood 알고리즘과 Maximum Slope 알고리즘을 적용하여 비교하였으며, 경사방향, 고도뿐만 아니라 최대경사방향의 곡률과 그 수직인 면에 대한 곡률을 분석에 이용하였다. 그 결과 최대경사방향 경사도 $40^{\circ}-45^{\circ}$ 구간이 상대적으로 매우 위험한 것으로 나타났으며 최대경사방향에 수직으로 오목한 사면이 더 위험한 것으로 분석되었다.

• 한국산업융합학회 논문집
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• 제25권1호
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• pp.61-70
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• 2022

Fire damage time in high-rise buildings and wildland fire increasing every year. The use of high-pressure fire pumps is required to effectively extinguish fires. Reflecting the curvature effect of the fire hose occurring at the actual fire fighting site, this study provides a database of pressure drop, discharge velocity and maximum discharge height through C FD numerical analysis and it can provide using standards for fire extinguishing. Two Reynolds numbers of 200000 and 400000 were numerically analyzed at 0° -180° bending with water of 25℃ as a working fluid in hoses with a diameter of 65mm, a length of 15m, and a radius of curvature of 130mm. Realizable k-ε turbulence model was used and standard wall function was used. The pressure drop increases as the bending angle increases, and the maximum value at 90° and then decreases. The increasing rate is greater than the decrease. The velocity of the secondary flow also decreases after having the maximum value at 90°. The decreasing rate is greater than the increase. The turbulent kinetic energy increases to 120° and decreases with the maximum value. Pressure drop, velocity of the secondary flow, and turbulence kinetic energy are measured larger in the second bending region than in the first bending region.

• 대한수학회보
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• 제50권1호
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• pp.97-103
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• 2013

As a suitable application of the well known generalized maximum principle of Omori-Yau, we obtain rigidity results concerning to a complete hypersurface immersed with bounded mean curvature in the $(n+1)$-dimensional hyperbolic space $\mathbb{H}^{n+1}$. In our approach, we explore the existence of a natural duality between $\mathbb{H}^{n+1}$ and the half $\mathcal{H}^{n+1}$ of the de Sitter space $\mathbb{S}_1^{n+1}$, which models the so-called steady state space.