• Journal of Astronomy and Space Sciences
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• v.16 no.2
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• pp.255-264
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• 1999

We calculate the theoretical line profiles in order to investigate the influence of various velocity parameters. Line profiles are calculated by using the exponential velocoty law with two acceleration regions for orbital phases $\phi$ = 0.07 and $\phi$ = 0.06. From this compttation we find that the influence of the wind velocity gradient on a giant star is more important in the region near the star than in the region away from the star. The observed lines show stronger emission than the calculated line profiles and we interpret the difference is caused by the inhomogeniety in the atmosphere of 32 Cyg.

• Publications of The Korean Astronomical Society
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• v.6 no.1
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• pp.16-26
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• 1991

스펙트럼선의 선폭증대 현상을 방출영역 내 기체입자들이 열운동에 의한 단순 도플러 효과로 가정하여 중심에서 어느 한쪽으로 심하게 치우친 스펙트럼 선윤곽를 해석한다. 본 연구에서는 태양활동영역에서 흔히 관측되는 좌우 비대칭의 선윤곽을 서로 다른 가우스속도분포의 기체성분들이 시선방향으로 중첩된 결과라 해석하고, 최소자승법을 이용한 비선형 선윤곽 맞춤질에 의해 스펙트럼 방출영역에서 떨어져 나가는 기채들의 온도 및 분출속도에 관련된 도플러선폭과 도플러이동량을 구하였다.

• The Transactions of the Korea Information Processing Society
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• v.5 no.11
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• pp.3010-3023
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• 1998

GA has a fast convergence speed in searching the one point around optimal value. But it's convergence time increase in searching the region around optimal value because it has no regional searching mechanism. BP has the tendency to converge the local minimum because it has global searching mechanism. To overcome these problems, a method in which a genetic algorithm and a back propagation are applied in turn is proposed in this paper. By using a genetic algorithm, we compute optimal synaptic strength and offset value. And then, these values are fed to the input of the back propagation. This proposed method is superior to each above method in improving the convergence speed.

• Geophysics and Geophysical Exploration
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• v.2 no.3
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• pp.154-158
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• 1999

This paper introduces a partial edge detection technique, that improves the processing time of an automatic change tracking system for multi-temporal images. In the conventional change tracking systems for multi-temporal images, the edge detection is performed over the whole image. In the proposed method, however, the necessary portions for the edge detection is selected first and the edge detection is performed over the selected parts only. As a consequence, the improvement in the processing time could be achieved. The proposed change tracking system is expected to be utilized as a very efficient tool to configure changes in large data set such as remotely sensed satellite imagery or geophysical time laps images.

• Proceedings of the Korea Multimedia Society Conference
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• 2003.05b
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• pp.460-463
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• 2003

본 논문은 프리미티브 모델을 바탕으로 윤곽선 추출하여 효율적으로 홀 채워서 결과 영상의 질과 속도를 향상시키는 알고리즘을 제시한다. 이 알고리즘은 입력 영상에서 뷰의 위치와 방향이 바뀌어 홀이 발생하면 그 홀을 동일 프리미티브의 윤곽선을 이용하여 프리미티브 내의 영상 정보만을 이용하므로 이질감이 작고 홀 주위의 모든 점들의 영상 정보를 이용하여 결과 영상의 질을 향상 시켰다.

• Journal of the Korea Society of Computer and Information
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• v.3 no.1
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• pp.81-94
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• 1998

In order to extract the contour of interesting object in the image, Kass suggested the Active Contour Model called "Snakes". Snakes is a model which defines the contour of image energy. It also can find the contour of object by minimizing these energy functions. The speed of this model is slow and this model is sensitive of initialization. In order to improve these problems, Gunn extracted the accurate contour by using two initialization. and operated to less sensitive of initialization. This method could extract more accurate contour than the existing method, but it had no effect in the speed and it was sensitive of noise. This paper applied to the Energy Minimization Algorithm about only the pixel within the window applying the window of 8$\times$8 size at each contour point consisting Snakes in order to solve these problems. The method offered in this paper is applied to extract the contour of original image and cup image added to gaussian noise. By tracking the face using this offered method, it is applied to virtual reality and motion tracking. tracking.

• Journal of Astronomy and Space Sciences
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• v.15 no.1
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• pp.101-110
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• 1998

We calculated line profiles of 32 Cyg with an assumed $str{\"{o}}mgren$ sphere at orbital phases 0.06 and 0.78. The wind models with $Alfv\'{e}n$ waves show diminished line profiles compared to those of the models using power velocity laws. The reduced density of absorbers in HII region produce weak profiles, but line profiles at ${\phi}=0.06$ do not show the differences except in the red edge of absorption. At ${\phi}=0.78$ however, we could reproduce the line profiles of Alfven waves model by the power law models with two velocity gradients. It suggests that the power law model with 2 acceleration regions could reduce the errors in the theoretical line formation with no consideration of wind acceleration mechanism.nism.

• Journal of Astronomy and Space Sciences
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• v.9 no.1
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• pp.120-125
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• 1992

The normalized line profiles of VV Cep have been calculated by integrating the equation of transfer. The Sobolev theory was adopted and the wind velocity distribution was assumed to be V(r) = V$\infty(1-R_c/r)^{1/2}$. The peaks of the line profiles for the phase 0.06 and 0.80 appear at near half maximum and zero velocity surface of the wind, respectively.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.153-163
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• 2004

This paper presents a video tracking method for a deformable moving object using an active contour model in the image sequences. It is quite important to decide the local convergence directions of the contour points for correctly extracting the boundary of the moving object with deformable shape. For this purpose, an energy function for the active contour model is newly proposed by adding a directional energy term using a frame difference map to tile Greedy algorithm. In addition, an updating rule of tile frame difference map is developed to encourage the stable convergence of the contour points. Experimental results on a set of synthetic and real image sequences showed that the proposed method can fully track the deformable object while extracting the boundary of the object elaborately in every frame.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.06a
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• pp.142-145
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• 2001

본 논문에서는 얼굴추출을 하는데 있어서 빠른 속도로 얼굴의 구성요소들을 분할하고 추출한다. 효율적인 분할과 추출물 위해서 3가지의 정보를 사용한다. 첫 번째는 얼굴의 색상정보로써 배경 속의 얼굴을 찾는데 이용한다. 두 번째는 얼굴의 윤곽선 정보로 얼굴의 구성요소를 추출해 내는데 사용한다. 세 번째는 얼굴의 구조적인 정보를 이용하여 색상 및 윤곽선 정보를 이용하여 추출된 요소에 대해 얼굴의 다른 구성요소를 추출하는데 이용한다.