• International Journal of CAD/CAM
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• 제8권1호
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• pp.11-20
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• 2009

The conventional methods of boundary-conformed 2D surfaces generation usually yield some problems. This paper deals with two boundary-conformed 2D surface generation methods, one conventional approach, the linear Coons method, and a new method, boundary-conformed interpolation. In this new method, unidirectional 2D surface has been generated using some of the geometric properties of the given boundary curves. A method of simultaneous displacement of the interpolated curves from the opposite boundaries has been adopted. The geometric properties considered for displacements include weighted combination of angle bisector and linear displacement vectors at all the data-points of the two opposite generating curves. The algorithm has one adjustable parameter that controls the characteristics of transformation of one set of curves from its parents. This unidirectional process has been extended to bi-directional parameterization by superimposing two sets of unidirectional curves generated from both boundary pairs. Case studies show that this algorithm gives reasonably smooth transformation of the boundaries. This algorithm is more robust than the linear Coons method and capable of resolving the 2D boundary-conformed parameterization problems.

• 정보처리학회논문지B
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• 제17B권5호
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• pp.375-380
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• 2010

객체 윤곽을 추출하는 대부분의 기존 방법들은 단일객체의 윤곽검출에 대해 연구하였다. 그러나, 실 세계에서는 복수객체가 일반적이다. 본 논문에서 제안한 복수객체 윤곽추출 알고리즘은 2 단계로 구성된다. 첫 번째 단계는 외적 및 내적을 사용하여 초기에 복수객체를 포함한 윤곽을 고속으로 분리하고 연결하여 각각이 윤곽이 단일 개체만을 포함하는 방법을 제안한다. 두 번째 단계는 각각의 윤곽에 포함된 단일 객체의 윤곽을 추출하는 개선된 능동윤곽모델 알고리즘을 설명한다. 여러 실험영상에 대한 실험결과는 다른 방법과 비교하여 속도가 빠르며 정확하게 윤곽을 추출한다.

• 한국정밀공학회지
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• 제12권2호
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• pp.112-122
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• 1995

While many surfaces such as automobile outer panels, ship hulls and airfoils are characterized by their smooth, free-form shapes, a far larger class of functional surfaces are characterized by highly irregular, multi-featured shapes consisting of pockets, channels, ribs, etc. In constaract to the design of aesthetic, free-form surfaces, functional surface design can perhaps best be viewed as a process of assembling a collection of known component surfaces to form a single compound surface. In this paper, we presents a feature-based functional surface modeling method. A single feature involves a secondary surface, which we must join to a primary surface with a smooth transition between two boundary courves. Through recursive blending of a secondary surface with the primary surface, the mullti-featured surface is represented. After constructing a compound surface, we generate the Z-map for NC machining of the surface. Offsetting the Z-map using the inverse offsetting technique, we get CL tool paths with out gouging.

• 대한의용생체공학회:의공학회지
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• 제33권4호
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• pp.169-176
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• 2012

Tumor cell morphology is closely related to its migratory behaviors. An active tumor cell has a highly irregular shape, whereas a spherical cell is inactive. Thus, quantitative analysis of cell features is crucial to determine tumor malignancy or to test the efficacy of anticancer treatment. We use 3D time-lapse phase-contrast microscopy to analyze single cell morphology because it enables to observe long-term activity of living cells without photobleaching and phototoxicity, which is common in other fluorescence-labeled microscopy. Despite this advantage, there are image-level drawbacks to phase-contrast microscopy, such as local light effect and contrast interference ring. Therefore, we first corrected for non-uniform illumination artifacts and then we use intensity distribution information to detect cell boundary. In phase contrast microscopy image, cell is normally appeared as dark region surrounded by bright halo ring. Due to halo artifact is minimal around the cell body and has non-symmetric diffusion pattern, we calculate cross sectional plane which intersects center of each cell and orthogonal to first principal axis. Then, we extract dark cell region by analyzing intensity profile curve considering local bright peak as halo area. Finally, we calculated the Fourier descriptor that morphological characteristics of cell to classify tumor cells into active and inactive groups. We validated classification accuracy by comparing our findings with manually obtained results.

• 한국전자파학회논문지
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• 제10권3호
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• pp.419-429
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• 1999

전파의 유효 수신 신호 도달영역을 정확히 식별하는 것은 기지국 최적화를 이룩하는데 있어 가장 중요한 요소중 하나이다. 서울 도심 지역과 같이 고층건물이 밀집되어 있고, 넓은 도로와 좁은 도로가 불규칙적으로 배치되어 있으며, 고개와 강 등이 혼재된 지역에서도 높은 정확도를 갖는 전파손실 예측모델을 소개한다. 이 모델은 기 측정된 필드데이터로 훈련된 신경회로망을 기반으로 한다. 전파손실에 영향을 주는 가장 기본적인 변수들은 3차원 DEM 데이터와 벡터 데이터로부터 추출하여 신경회로망의 입력으로 사용한다. 학습이 완료된 신경회로망은 전파손실 모델의 근사함수이며, 학습에 사용된 필드 측정데이터에 포함되지 않은 타지역에서도 정확한 예측이 가능한 일반화 능력을 갖는다. 서울 도심 지역의 실제 서비스 환경에 대한 비교 실험결과를 통해 제안하는 모델의 우수성을 보인다.

• 자원환경지질
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• 제30권6호
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• pp.553-566
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• 1997

Origin, behavior and enrichment of environmental toxic elements from the Deokpyeong area were investigated on the basis of major, trace and rare earth element geochemistry. Coaly metapelites of the Deokpyeong area are subdivided into grey phyllite, dark grey phyllite, coaly slate and black slate, which are interbedded along the Ogcheon Supergroup. The coaly slate had been mined for coal, but mining is closed. The coaly and black slates are lower contents of $SiO_2$ and $Al_2O_3$, and higher contents of LOI, CaO, $Na_2O$ and BaO as compared with the phyllitic rocks. Rare earth elements are highly enriched in the coaly and black slate. Average compositions (ppm) of minor and/or environmental toxic elements in the coaly and black slate are revealed as As=127, Ba=30,163, Cd=18, Cr=740, Cu=84, Mo=378, Pb=43, Sb=12, Se=44, U=144, V=8,147 and Zn=292, which are extremely high concentrations than those in the NASC compositions. Major elements (average enrichment index; 5.34) in the coaly metapelites are mostly depleted, excepting $P_2O_5$ and BaO, normalized by NASC. Rare earth elements (average enrichment index; 1.48) are enriched in the coaly slate. On the basis of NASC, minor and/or environmental toxic elements in the coaly metapelites were strongly enriched of all the elements with the exception of Co, Cs, Ni and Sr. Average enrichment index of trace elements in coaly metapelite is 31.51 (coaly slate; 51.94 and black slate; 15.46). Especially, enrichment index of potentially toxic elements (As, Ba, Cr, Cu, Mo, Ni, Sb, Se, U, V and Zn) of the rock is 46.10 (grey phyllite; 7.15, dark grey phyllite; 4.77, coaly slate; 88.96 and black slate; 22.11). These coal formations were deposited in basin of boundary between terrestrial and marine environments deduced to carbon, sulfur (C/S=2.2 to 275.7), trace and rare earth elements characteristics. Irregular behavior and dispersion between major, minor and rare earth elements of those metapelites indicates a variable source materials, incomplete mixing of differential source and/or reequilibrium of diagenesis and metamorphism.