• 한국조경학회지
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• 제13권2호
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• pp.37-70
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• 1985

The purpose of this study is to present objective basic data for environmental design by the quantitative analysis of visual quality emboded in physical environment. For this, as for the front garden of high schools, the spatial image was measured by the S.D. Scale Method, Factor Analysis was proceeded by the principal component analysis and the visual preference was investigated by the Paired Comparision Method. The scale values of plain and unpleasant road surface and external appearance of buildings, which are related to emotions of simpleness fell from straightness and stability, were found to be high. But, except for the road surface of Kyunggi High School, scale values of variables explaining the variation of the quality of materials, level of floor and rythm were generally low. For all green spaces, scale values of variables explaining the degree of pleasantness was found to be generally high. And, those explaining tidiness and characteristics of green spaces were not in the same tendency. But, the green spaces of Youngdong High school can be considered to the space with plenty of visual absorption uniqueness were high. As for the correlation between variables, variables for green spaces(12 and 26) and those for overall view of front garden( 1 and 4) revealed high positive correlation. Also, "order - disorder" and "convenient- incovenient" included in road surface variable can be regarded to have the same meaning since the correlation coefficient between them is very high, 0.7045. Image variables including road surface, external appearance of buildings, green spaces and overall view of front garden showed 91.21~61.08% of total variance. Thus, the remains can be considered to be the error valiance or specific variance. In Fctor I, II and III, main components explaining the road surface image of front gardens are order, hardness, texture, color, gradient and rythm. As for the external appearance of b wilding, variables of color, hardness, stability, peculiality and shape revealed high values of factor load. For all variables, communality was drastically high and ellen values and common variance were found to be very high in Factor I. As for the front gardens, variables explaining volume and peculiarity were found to be the main components of Factor I. In Factor II and III, variables of factor load were tidiness, pleasantness.

• 한국의학물리학회지:의학물리
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• 제19권4호
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• pp.269-275
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• 2008

슬관절 퇴행성 질환을 진단하기 위하여 자기공명영상(magnetic resonance imaging: MRI)이 많이 사용되지만 간혹 슬관절 병후 및 예후를 잘못 진단하는 경우가 종종 발생한다. 본 연구에서는 슬관절 질환의 진단에 도움을 주기 위하여 자화전이(magnetization transfer: MT) 영상법을 소개하고자 한다. 슬관절 환자 7명으로부터 스핀 에코(SE) T2 강조 영상(3,400-3,500/90-100 ms)과 슬관절 환자 7명으로부터 FSE T2 강조 영상(4,500-5,000/100-108 ms)과 또한 슬관절 환자 3명으로부터 gradient echo (GRE) T2 강조 영상들(9/4.56 ms, 50 flip angle, NEX 1)을 획득하였다. 6명의 슬관절 환자에서 지방 억제가능 T2 강조 STIR 펄스시퀀스(TR/TE=2894-3215 ms/70 ms, NEX 3, ETL 9)를 사용하였다. 지방 포화도에 있어서 위상감도 방법은 Larmor frequency 차이에 따른 위상 차이를 이용하므로, 각각의 픽셀에 대한 자화전이율(magnetization transfer ratio: MTR)의 측정은 포화된 영상과 포화되지 않은 영상의 비율에 따라 산출하였다. 따라서 각 입력된 영상들은 동차원성을 가지고, 시각적으로 신호강도 정도가 회색의 명암도만으로 평가될 수 있기 때문에 생리학적, 정량적 진단을 위하여 3차원 등방성 체적영상과 자기공명 삼원색을 매핑하였고 정량적 특정은 자화전이율 지도로서 표현하였다. 자화전이율 영상은 병변 부위에서 높은 대조도를 나타내어 환자의 병태를 추적하는데 도움을 주었고 정량화하였다. 자화전이율 영상들과 기존의 MRI 사이에 명암도 차이는 회색상으로 표현되며, 자화전이율 영상화의 효과에 대해 프로파일 그래프는 자화전이 펄스로 인하여 신호강도에 있어서 정량적 측정값이 상대적으로 감소하였다. 슬관절의 정확한 병리상태를 진단하기 위해 프로파일 그래프의 측정값을 영상과 함께 표현하였다. 본 연구에서 수행한 예비적 데이터들을 통하여 슬관절의 자화전이율 영상들이 매우 임상학적으로 유용함을 확인하였다. 자화전이율 영상에 대한 물리적 변화를 관찰함으로써 자화전이율 영상에 대한 물리적, 기술적 기반에 대한 더 많은 통찰력을 제공할 수 있다. 무릎 질환 환자의 자화전이율 영상들을 이용하여 매우 높은 대조도를 확보할 수 있으므로 슬관절 질환의 정밀 진단에 매우 도움을 줄 수 있다.

• Journal of applied mathematics & informatics
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• 제25권1_2호
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• pp.435-443
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• 2007

Computing the interior spectrum of large sparse generalized eigenvalue problems $Ax\;=\;{\lambda}Bx$, where A and b are large sparse and SPD(Symmetric Positive Definite), is often required in areas such as structural mechanics and quantum chemistry, to name a few. Recently, CG-type methods have been found useful and hence, very amenable to parallel computation for very large problems. Also, as in the case of linear systems proper choice of preconditioning is known to accelerate the rate of convergence. After the smallest eigenpair is found we use the orthogonal deflation technique to find the next m-1 eigenvalues, which is also suitable for parallelization. This offers advantages over Jacobi-Davidson methods with partial shifts, which requires re-computation of preconditioner matrx with new shifts. We consider as preconditioners Incomplete LU(ILU)(0) in two variants, ever-relaxation(SOR), and Point-symmetric SOR(SSOR). We set m to be 5. We conducted our experiments on matrices from discretizations of partial differential equations by finite difference method. The generated matrices has dimensions up to 4 million and total number of processors are 32. MPI(Message Passing Interface) library was used for interprocessor communications. Our results show that in general the Multi-Color ILU(0) gives the best performance.

• 한국전산유체공학회지
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• 제15권2호
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• pp.28-34
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• 2010

Conductive and radiative thermal model configurations of an imager of a geostationary satellite are presented. A two-plane method is introduced for three dimensional conductive coupling which is not able to be treated by thin shell plate thermal modeling technique. Especially the two-plane method is applied to massive matters and PIP(Payload Interface Plate) in the imager model. Some massive matters in the thermal model are modified by adequate correction factors or equivalent thickness in order to obtain the numerical results of thermal modeling to be consistent with the analytic model. More detailed nodal breakdown is specially employed to the object which has the rapid temperature gradient expected by a rule of thumb. This detailed thermal model of the imager is supposed to be used for analyses and test predictions, and be correlated with the thermal vacuum test results before final in-flight predictions.

• 한국컴퓨터그래픽스학회논문지
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• 제24권3호
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• pp.43-48
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• 2018

본 연구는 핸드폰과 같은 모바일 기기로 촬영한 문서 이미지에서 조명 조건들로 인해 발생한 부드러운 그림자를 제거하는 방법을 제안한다. 본 방법은 기존의 피라미드 기반 방법이나, 경계법 방법에 비해 더 좋은 결과를 만들어 낸다. 방법의 기본아이디어는 촬영된 문서 이미지로부터 이미지 지역 통계를 활용하여 글자나 그림 등의 흥미로운 내용이 있는 부분을 분리하고, 이 분리된 부분에 대해 적응적인 밝기 및 대조 조정과 레벨 변환을 수행하여 이미지를 더욱 선명하게 하는 것이다. 또한 내용이 없는 부분에 대해서는 부드러운 채움을 위해 이미지 변형량 기반의 빈 곳 메우기 방법을 이용한다.

• 한국멀티미디어학회논문지
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• 제11권5호
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• pp.623-632
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• 2008

본 논문에서는 영상 볼륨 데이터의 내부 3차원 객체들을 표현하기 위하여 색상 전이함수와 불투명도 전이함수를 사용하였다. 대체로 전이함수에서 경계부분이 만나는 지점의 값 설정이 모호하므로 볼륨 렌더링의 대상이 되는 시각 객체를 구분하기 위하여 영상이 가지는 특징들과 각 객체들 사이의 분할방법으로 객체 경계의 특징값 추출에 역점을 두었다. 따라서 공간상의 영상 기울기 특징 값을 추출하였으며 GPU의 효율을 증대시켜서 다차원 전이함수를 생성하였다. 그러므로 이 함수들을 그래픽 하드웨어 기반에 3차원 질감사상의 객체 경계 가시화 방법을 수행함으로써 좋은 연구결과를 얻게 되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 심포지엄 논문집 정보 및 제어부문
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• pp.120-121
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• 2006

In this paper, We have designed a face recognition system based on the embedded Linux. This paper has an aim in embedded system to recognize the face more exactly. At first, the contrast of the face image is adjusted with lightening compensation method, the skin and lip color is founded based on YCbCr values from the compensated image. To take advantage of the method based on feature and appearance, these methods are applied to the eyes which has the most highly recognition rate of all the part of the human face. For eyes detecting, which is the most important component of the face recognition, we calculate the horizontal gradient of the face image and the maximum value. This part of the face is resized for fitting the eye image. The image, which is resized for fit to the eye image stored to be compared, is extracted to be the feature vectors using the continuous wavelet transform and these vectors are decided to be whether the same person or not with PNN, to miminize the error rate, the accuracy is analyzed due to the rotation or movement of the face. Also last part of this paper we represent many cases to prove the algorithm contains the feature vector extraction and accuracy of the comparison method.

• 천문학회지
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• 제45권3호
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• pp.71-84
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• 2012

We present a photometric study of the globular clusters (GCs) in the Virgo giant elliptical galaxy M86 based on Washington $CT_1$ images. The colors of the GCs in M86 show a bimodal distribution with a blue peak at ($C-T_1$) = 1.30 and a red peak at ($C-T_1$) = 1.72. The spatial distribution of the red GCs is elongated similar to that of the stellar halo, while that of the blue GCs is roughly circular. The radial number density profile of the blue GCs is more extended than that of the red GCs. The radial number density profile of the red GCs is consistent with the surface brightness profile of the M86 stellar halo. The GC system has a negative radial color gradient, which is mainly due to the number ratio of the blue GCs to the red GCs increasing as galactocentric radius increases. The bright blue GCs in the outer region of M86 show a blue tilt: the brighter they are, the redder their mean colors get. These results are discussed in comparison with other Virgo giant elliptical galaxies.

• Bulletin of the Korean Chemical Society
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• 제24권10호
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• pp.1433-1436
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• 2003

A new method for the simultaneous determination of heavy metal ions in cigarette material by microwave digestion and reversed-phase high-performance liquid chromatography (RP-HPLC) has been developed. The cigarette material was digested by microwave digestion. Lead, cadmium, mercury, nickel and tin ions in the digested samples were pre-column derivatized with tetra-(2-chlorophenyl)-porphyrin ($T_2$-CPP) to form color chelates, which were then enriched by solid phase extraction with a $C_{18}$ cartridge. The chelates were separated on a Waters Xterra$^{TM}RP_{18}$ column by gradient elution with methanol (containing 0.05 mol/L pyrrolidine-aceticacid buffer salt, pH = 10.0) and acetone (containin0.05 mol/L pyrrolidine-acetic acid buffer salt, pH = 10.0)as mobile phase at a flow rate of 0.5mL/min and analyzed with a photodiode array detector from 350-600 nm. The detection limits of lead, cadmium, mercury, nickel and tin were 4,3,3,8 and 5 ng/L, respectively, in the original samples. This method was afforded good results.

• 한국재료학회지
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• 제30권11호
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• pp.627-635
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• 2020

3D printing technology is a processing technology in which 3D structures are formed by fabricating multiple 2D layers of materials based on 3D designed digital data and stacking them layer by layer. Although layers are stacked using inkjet printing to release various materials, it is still rare for research to successfully form a product as an additive manufacture of multi-materials. In this study, dispersion conditions are optimized by adding a dispersant to an acrylic monomer suitable for inkjet printing using Co₃O₄ and Al₂O₃. 3D structures having continuous composition composed of a different ceramic material are manufactured by printing using two UV curable ceramic inks whose optimization is advanced. After the heat treatment, the produced structure is checked for the formation and color of the desired crystals by comparing the crystalline analysis according to the characteristics of each part of the structure with ceramic pigments made by solid phase synthesis method.