• Journal of the Optical Society of Korea
• /
• 제18권6호
• /
• pp.706-713
• /
• 2014

An enhanced 360-degree integral-floating three-dimensional display system using a hexagonal lens array and a hidden point removal operator is proposed. Only the visible points of the chosen three-dimensional point cloud model are detected by the hidden point removal operator for each rotating step of the anamorphic optics system, and elemental image arrays are generated for the detected visible points from the corresponding viewpoint. Each elemental image of the elemental image array is generated by a hexagonal grid, due to being captured through a hexagonal lens array. The hidden point removal operator eliminates the overlap problem of points in front and behind, and the hexagonal lens array captures the elemental image arrays with more accurate approximation, so in the end the quality of the displayed image is improved. In an experiment, an anamorphic-optics-system-based 360-degree integral-floating display with improved image quality is demonstrated.

• 대한한의학원전학회지
• /
• 제22권1호
• /
• pp.121-130
• /
• 2009

Traditionally, Korean Medicine put emphasis on the treatment and health-preserve method that corresponds with circulation of nature. And acupuncture is no exception to this rule. In "Hwangjenaegyeong(黃帝內經)", some chapters present method that is changed according to the seasons. Among the chapters, there are some difference, but we can find a general theory. In spring, Yanggi(陽氣) is coming out but not strong and cannot diffuse. so the Yanggi(陽氣) hang up the middle of outer layer. Therefore, we can take some acupoints around the muscle interspace[分腠] or tiny branches of Meridian[孫絡]. In summer, Yanggi(陽氣) flourish and boil all around of the outer layer. So, we can take some acupunctural points from skin to the yang-meridian. In both fall and winter, five su point[五輸穴] make up almost of point. in fall, yanggi begin convergence. we can remove the Eum-pathogen[陰邪] and help the normal convergence by using Stream point[腧穴], River point[經穴] and Sea point[合穴]. In winter, Eum surround so solidly that the neo Yanggi(陽氣) cannot come out. So, we can break the yin by using Well point[井穴] and make be strong by Spring point[滎穴]. If we Study the method that correspond with the seasonal circulation more, we will be able to treat diseases more minutely.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
• /
• pp.617-621
• /
• 2001

This paper presents a maximum power point tracking algorithm for Photovoltaic array using only instantaneous output current information. The conventional Hill climbing method of peak power tracking has a disadvantage of oscillations about the maximum power point. To overcome this problem, we have developed a algorithm, that will estimate the duty ratio corresponding to maximum power operation of solar cell. The estimation of the optimal duty ratio involves, finding the duty ratio at which integral value of output current is maximum. For the estimation, we have used the well know Lagrange's interpolation method. This method can track maximum power point quickly even for changing solar insolations and avoids oscillations after reaching the maximum power point.

• Journal of applied mathematics & informatics
• /
• 제29권5_6호
• /
• pp.1167-1178
• /
• 2011

In this paper, we further investigate the local Hermitian and skew-Hermitian splitting (LHSS) iteration method and the modified LHSS (MLHSS) iteration method for solving generalized nonsymmetric saddle point problems with nonzero (2,2) blocks. When A is non-symmetric positive definite, the convergence conditions are obtained, which generalize some results of Jiang and Cao [M.-Q. Jiang and Y. Cao, On local Hermitian and Skew-Hermitian splitting iteration methods for generalized saddle point problems, J. Comput. Appl. Math., 2009(231): 973-982] for the generalized saddle point problems to generalized nonsymmetric saddle point problems with nonzero (2,2) blocks. Numerical experiments show the effectiveness of the iterative methods.

• International Journal of Precision Engineering and Manufacturing
• /
• 제1권1호
• /
• pp.15-21
• /
• 2000

This study presents a procedure for analyzing chip-tool friction and shear processes in 3-D cutting with a single point tool. The edge of a single point tool including a circular nose is modified to an equivalent straight edge, thereby reducing the 3-D cutting with a single point tool to the equivalent of oblique cutting. Then, by transforming the conventional coordinate systems and using the measurements of three cutting force components, the force components on the rake face and shear plane of the equivalent oblique cutting system can be obtained. As a result, the chip-tool friction and shear characteristics of 3-D cutting with a single point tool can be assessed.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.161-162
• /
• 2015

최근 세계적으로 전력계통의 대륙 간 연계나 신재생에너지, 분산전원의 계통 연계를 위해 HVDC(High voltage Direct Current)에 대한 연구가 활발히 진행되고 있다. 대용량, 장거리 송전이 필요한 경우 HVAC에서의 전력손실과 송전거리의 한계를 극복하기 위하여 HVDC가 새로운 대안으로 떠오르고 있으며, LCC(Line commutated Converter)와 VSC(Voltage Source Converter)의 기술발전이 비약적으로 이뤄지고 있다. 특히, DC Grid화를 위해서 유럽에서는 해상풍력을 연계한 Windfarm을 DC Grid화 하는 프로젝트가 활발히 진행되고 있다. 이러한 신재생 에너지의 계통 연계를 위해서 DC Grid가 본격적으로 논의가 되고 있고 관련분야에서는 기술개발을 앞다퉈 진행하고 있는 상황이다. DC Grid 구현을 위해 VSC HVDC가 최근 주목받고 있으며, VSC로 연계된 DC Grid의 AC 계통과의 연계를 위해 가장 필요한 것이 바로 DC 차단기라고 할 수 있겠다. 본 논문에서는 DC Grid의 고장분석을 위한 기초연구로써 MMC(Modular Multilevel Converter) VSC를 기반으로 한 Point-to-Point HVDC Grid에서의 DC 고장에 대한 분석을 실시하였으며 그 특징을 분석하였다.

• Journal of Power Electronics
• /
• 제2권3호
• /
• pp.155-161
• /
• 2002

This paper presents a maximum power point tracking algorithm for Photovoltaic array using only instantaneous output current information. The conventional Hill climbing method of peak power tracking has a disadvantage of oscillations about the maximum power point. To overcome this problem, we have developed an algorithm that will estimate the duty ratio corresponding to maximum power operation of solar cell. The estimation of the optimal duty ratio involves, finding the duty ratio at which integral value of output current is maximum. For the estimation, we have used the well know Lagrange's interpolation method. This method can track maximum power point quickly even for changing solar isolation and avoids oscillations after reaching the maximum power point.

• International Journal of Safety
• /
• 제9권2호
• /
• pp.6-10
• /
• 2010

The flash point of liquid solution is one of the most important flammability properties that used in hazard and risk assessments. Minimum flash point behaviour (MFPB) is showed when the flash point of a liquid mixture is below the flash points of the individual components. In this paper, the lower flash points for the flammable binary system, n-decane+n-octanol, were measured by Pensky-Martens closed cup tester. This binary mixture exhibited MFPB. The measured flash points were compared with the values calculated by the Raoult's law and the optimization method using van Laar and UNIQUAC equations. The optimization method were found to be better than those based on the Raoult's law, and successfully estimated MFPB. The opimization method based on the van Laar equation described the experimentally-derived data more effectively than was the case when the prediction model was based upon the UNIQUAC.

• 방송공학회논문지
• /
• 제25권5호
• /
• pp.798-807
• /
• 2020

디지털 카메라와 휴대폰 카메라의 발달로 인해 이미지를 기반으로 3차원 물체를 복원하는 기술이 크게 발전했다. 하지만 Structure-from-Motion(SfM)과 Multi-view Stereo(MVS)를 이용한 결과인 dense point cloud에는 여전히 듬성한 영역이 존재한다. 이는 깊이 정보를 추정하는데 있는 어려움과, 깊이 지도를 point cloud로 fusing할 때 이웃 영상과의 깊이 정보가 불일치할 경우 깊이 정보를 삭제하고 point를 생성하지 않았기 때문이다. 본 논문에선 평면을 모델링하여 삭제된 깊이 정보에 새로운 깊이 정보를 부여하고 point를 생성하여 기존 결과보다 dense한 point cloud를 생성하는 알고리즘을 제안한다. 실험 결과를 통해 제안하는 알고리즘이 효과적으로 기존의 방법보다 dense한 point cloud를 생성함을 확인할 수 있다.

• Korean Journal of Acupuncture
• /
• 제27권3호
• /
• pp.67-78
• /
• 2010

Objectives : The aim of the study is to draw a consensus in acupuncture point locations (APLs) which are frequently used in experimental animal studies. Well-documented APL is needed not only for human but also for rodents because stimulation of precise point is very important factor in acupuncture. Methods : We organized a committee with experts to reach a consensus on the APLs in rat. The subject points were limited to 22 points used in the papers published at international peer-review journals. To describe point locations, we adopted the syntax of sentence used in the WHO standard acupuncture point locations. Results : Locations of 22 acupuncture points such as ST36, LI4, PC6, and SP6 were described in English with photographic illustrations. Interestingly, we found that ST36 had been inserted into 2 different locations in rodent. Under consideration of practical use, the location of ST36 point was described in 2 different ways. Conclusion : We hope that newly developed APLs would be a good indicator of acupuncture experiments in rats and mice.