• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.241-244
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• 2002

Using ab initio method, we have studied the structural stabilities, the electronic structures and properties between the two isomers with $C_{2h}$ and $C_{2v}$ symmetry of AlN four-membered-ring single precursors $[Me_2AlNHR]_2$ (R = Me, $^iPr$, and $^iBu$). In the viewpoint of bond lengths in optimized structures, the N-C bonds are considerably affected by the change of the R groups bonded to nitrogen, but the bonding characters of the Al-N and Al-C bonds are little affected. Also the structural stabilities between the two isomers with $C_{2h}$ and $C_{2v}$ symmetry by using Hartree-Fock (HF) and the second order Moeller-Pleset (MP2) calculations agree well with the experimental results for the relative stability of bis(dimethyl- m-isopropylamido-aluminum) (BDPA) and bis(dimethyl- m-t-butylamido-aluminum) (BDBA), while the semiempirical AM1 and PM3 calculations for BDPA were reverse. Thus, our results may aid in designing an optimum precursor for a given process by explaining the experimental results through the elimination of the R groups bonded to nitrogen.

• 한국컴퓨터정보학회논문지
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• 제17권10호
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• pp.35-41
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• 2012

본 논문에서는 과분할 방지와 복잡한 현미경 세포영상의 자동 분할을 위한 새로운 마커 기반의 워터쉐드 알고리즘을 제안한다. 워터쉐드 방식은 접촉 또는 겹침으로 인한 복잡한 대상들을 분할하기 위해 효과적이며 보다 성공적인 적용을 위해 정확한 마커 추출이 선행되어야 한다. 세포 영상의 정확한 마커 추출을 위해 본 논문에서는 방사형 대칭성을 이용한 반복 보팅 알고리즘을 이용하였다. 합성 영상과 실제 영상에서도 기존의 다른 방식들에 비해 양호한 분할 결과를 보였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제14권3호
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• pp.1167-1187
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• 2020

With the development of medical imaging technology, image registration has been widely used in the field of disease diagnosis. The registration between different modal images of brain magnetic resonance (MR) is particularly important for the diagnosis of brain diseases. However, previous registration methods don't take advantage of the prior knowledge of bilateral brain symmetry. Moreover, the difference in gray scale information of different modal images increases the difficulty of registration. In this paper, a multimodal medical image registration method based on image segmentation and symmetric self-similarity is proposed. This method uses modal independent self-similar information and modal consistency information to register images. More particularly, we propose two novel symmetric self-similarity constraint operators to constrain the segmented medical images and convert each modal medical image into a unified modal for multimodal image registration. The experimental results show that the proposed method can effectively reduce the error rate of brain MR multimodal medical image registration with rotation and translation transformations (average 0.43mm and 0.60mm) respectively, whose accuracy is better compared to state-of-the-art image registration methods.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.259-260
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• 2006

The ESPI(Electronic Speckle Pattern Interferometry) is a real time, full-field, non-destructive optical measurement technique. In this study, ESPI is proposed for the purpose of vibration analysis for new material, composite material. Composite materials have various complicated characteristics according to the ply materials, ply orientations, ply stacking sequences and boundary conditions. Therefore, it is difficult to analysis composite materials. For efficient use of composite materials in engineering applications the dynamic behavior, that is, natural frequencies, nodal patterns should be informed. If use Time-Average ESPI, can analyze vibration characteristic of composite material by real time easily. This study manufactured laminated composite of symmetry, asymmetry two kinds that is consisted of CFRP(Carbon Fiber Reinforced Plastics) and shape of test piece is rectangular form.

• 대한공간정보학회지
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• 제10권3호
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• pp.79-87
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• 2002

항공사진에 포함된 사진 지표의 방사 및 기하 특성을 이용하여 지표의 중심 위치를 자동으로 인식하기 위한 접근 방법을 제안한다. 방사 특성에 기반을 둔 전략에 근거하여, 입력된 영상을 이진화한 다음 형태 연산자를 적용시켜 사진 지표가 있는 후보 영역을 추출한다. 기하 특성에 기반을 둔 전략에 근거하여 ${\bigtriangledown}^G$ 필터링과 대칭성 강조 필터링을 적용시킨 후, 대칭이 가장 강하게 나타나는 위치인 지표의 중심 위치를 구한다. 사진 지표를 포함하고 있는 66매의 영상에 대한 평가 결과 중심 위치가 수동으로 관측한 결과와 비교할 때 1 화소 정도의 차이로 얻어질 수 있었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1607-1612
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• 2004

Numerical simulations are performed to investigate the characteristics of flow past a sphere in uniform shear. The Reynolds numbers considered are Re=300, 425 and 480 based on the inlet center velocity and sphere diameter. The non-dimensional shear rate K of the inlet uniform shear is varied from 0 to 0.15. At Re=300, the head of the hairpin vortex loop always locates on the high-velocity side in uniform shear, and the flow maintains the planar symmetry. At Re=425 and 480, the irregularity in the location and strength of the hairpin vortex appearing in uniform inlet flow is much reduced in uniform shear, but the flows still keep the asymmetry for most inlet shear rates. However, in the cases of K=0.075 and 0.1 at Re=425, the flows become planar symmetric and their characteristics of the evolution of the hairpin vortex loops are different from those of asymmetric flows. A hysteresis phenomenon switching from the planar symmetry to the asymmetry (or vice versa) depending on the initial condition is also observed at Re=425.

• 대한물리치료과학회지
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• 제31권1호
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• pp.46-52
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• 2024

Background: This study aims to investigate compensatory strategy in a dog with glenoid dysplasia using kinetic gait analysis before and after reconstruction of medial patellar luxation. Design: Case report Method: On the platform, gait analysis was evaluated for a dog with congenital luxation and bilateral medial patellar luxation (MPL). A dog was evaluated for maximal vertical force (MVF), body load distribution (BLD), and symmetry index (SI), including the left forelimb with congenital luxation before MPL surgery, 15 days of surgery, and 40 days of surgery. Result:: In the comparison between the preoperative and the 15 days of surgery, the MVF of the bilateral forelimbs, especially in the non-affected forelimbs, increased, and the SI also increased. For BLD, the maximum load distribution increased, but the total load distribution decreased. In the comparison of 15 days and 40 days of surgery, MVF and BLD increased, and SI decreased on 40days of surgery. Conclusions: In a dog, the shift in weight load to the non-affected side occurs all the limbs, affecting the peak vertical force, weight load distribution, and symmetry index.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.733-736
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• 2005

This paper presents the design of two antennas for the Dual-channel Radiometers for Earth and Atmosphere Monitoring (DREAM) the main payload, will be launched at NARO space center in Korea in 2007. The antennas are designed to meet stringent requirements of a very high beam efficiency, good pattern symmetry, and low VSWR, at 23.8 GHz and 37 GHz bands. Corrugated horn antennas are used. The simulation results of the electrical performance are presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 정기총회 및 추계학술대회 논문집 학회본부
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• pp.188-191
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• 1993

Silicon flow sensor which can detect the magnitude and direction of two dimensional air flow was designed and fabricated by CMOS process and bulk micromachining technique. The flow sensor consists of three-layered dielectric diaphragm a heater at the center of the diaphragm and four thermopiles surrounding the heater at each side of diaphragm as sensing elements. This diaphragm structure contributes to improve the sensitivity due to excellent thermal isolation property of dielectric materials and its tiny thickness. The flow sensor has good axial symmetry to sense 2-D air flow with the optimized sensing position in the given structure. Measured sensitivity of our sensor is $18.7mV/(m/s)^{1/2}$.

• 한국자동차공학회논문집
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• 제17권1호
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• pp.1-11
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• 2009

This paper proposes an algorithm capable of detecting vehicles in front or in rear using a monocular camera installed in a vehicle. The vehicle detection has been regarded as an important part of intelligent vehicle technologies. The proposed algorithm is mainly composed of two parts: 1)hypothesis generation of vehicles, and 2)hypothesis verification. The hypotheses of vehicles are generated by the analysis of vertical and horizontal edges and the detection of symmetry axis. The hypothesis verification, which determines vehicles among hypotheses, is done by the AdaBoost algorithm. The proposed algorithm is proven to be effective through experiments performed on various images captured on the roads.