• Journal of the Optical Society of Korea
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• 제15권2호
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• pp.152-154
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• 2011

We propose a novel method which detects convex and concave corners using radial projection. The sum of two neighbors' differences at the local maxima or minima of the radial projection is compared with the angle threshold for detecting corners. In addition, the use of oriented bounding box trees and partial circles makes it possible to detect the corners of complex shapes. The experimental results show that the proposed method can separately detect the convex and concave corners, and that this method is scale invariant.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2012년도 제45차 동계학술발표논문집 20권1호
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• pp.189-192
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• 2012

게임 인공지능에서 경로 찾기는 매우 중요한 분야이다. 캐릭터나 NPC(Non Player Charater)가 목적지까지의 경로를 탐색하기 위해서는 복잡하게 구성된 게임 맵에서 오브젝트나 벽 등의 장애물을 회피하면서 가능한 최단 경로를 찾아야 한다. 기존의 일반적인 경로 찾기 알고리즘은 캐릭터의 움직임이 자유로운 간단한 게임 맵에서는 전역 최소해 탐색이 가능하다. 그러나 다양한 오브젝트 등이 배치된 큰 규모의 게임 맵에서는 캐릭터가 목적지까지의 경로를 탐색하는 과정에서 지역 최소해(Local Minima)로의 수렴이 발생함으로써 이를 탈피하는 것이 어렵고, 결국에는 목적지까지 도달하지 못하는 상황이 발생하게 된다. 본 논문에서는 이러한 기존 경로 찾기 알고리즘의 단점을 해결하기 위해 시뮬레이티드 어닐링 알고리즘을 제안하였다.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2001년도 춘계학술대회논문집:21세기 신지식정보의 창출
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• pp.318-324
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• 2001

In this paper we propose the adaptive scheme to place more search points as long as the operation tapability of the motion estimator in the video codec permits. And the proposed algorithm takes advantage of the intuitive fact that the quality of the decoded video is more degraded as the spatial frequency of the corresponding block is increased due to the augmentation of local minima per unit area. Thererore, we propose the scheme to enhance the quality by locating relatively more search points in the block with high frequency components by analyzing the spatial frequencies of the video sequence. As a result, the proposed scheme can adaptively place more search points possibly permitted by the motion estimator and guarantees better quality compared to the TSS and FS.

• 한국자동차공학회논문집
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• 제12권6호
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• pp.135-142
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• 2004

The severe frontal crash tests are NCAP with belted occupant at 35mph and FMVSS 208 with unbelted occupant at 25mph, This paper describes the design process of occupant protection systems, airbag and seat belt, under the two tests. In this study, NCAP simulations are performed by Monte Carlo search method and cluster analysis. The Monte Carlo search method is a global optimization technique and requires execution of a series of deterministic analyses, The procedure is as follows. 1) Define the region of interest 2) Perform Monte Carlo simulation with uniform distribution 3) Transform output to obtain points grouped around the local minima 4) Perform cluster analysis to obtain groups that are close to each other 5) Define the several feasible design ranges. The several feasible designs are acquired and checked under FMVSS 208 simulation with unbelted occupant at 25mph.

• Journal of Astronomy and Space Sciences
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• 제10권1호
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• pp.44-85
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• 1993

EA형이며 준분리형에 속하는 19개의 식쌍성에 대한 공전주기 변화를 조사하였다. 그런데 각 식쌍성의 주기 변화각 갑작스러운 주기 변화를 보이는 일차항의 광도요소를 갖는다는 가정하에 주기 변화를 분석하였다. 이러한 분석을 통하여 각 식쌍성의 주기 변화와 그 별의 물리량과의 상관관계를 조사하였다.

• Journal of Astronomy and Space Sciences
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• 제14권1호
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• pp.33-43
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• 1997

소백산 천문대의 61cm 망원경을 사용하여 1995년 10월부터 12월 사이의 10일 동안 CCD 측광관측에 의하여 EB형 식쌍성 V388 Cyg의 3색 (B, V&R)의 광도곡선을 얻었다. 새로운ㄴ 3색의 광도곡선을 Wilson-Devinney model에 동시에 적용하여 이 별의 궤도요소를 얻었다. 그 결과 현재로서는 V388 Cyg이 접촉형인지 준분리형인지를 판단하지 못하였다. 한편, 지금까지 발표된 이 별의 극심시각을 수집하여 주기변화를 조사하였으며, 그 결과 일정한 주기 감소를 나타내는 $-4.83{\times}10^{-10}$의 2차 함수를 포함하는 새로운 광도요소를 계산하였다.

• 전자공학회논문지A
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• 제31A권6호
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• pp.34-44
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• 1994

In this paper, an iterative inversion method in angular spectral domain is presented for microwave imaging of a perfectly conducting cylinder. Angular spectra are calculated from measured far-field scattered fields. And then both the propagating modes and the evanescent modes are defined. The center and initial shape of an unknown conductor may be obtained by the characteristics of angular spectra and the total scattering cross section (TSCS). Finally, the orignal shape is reconstructed by the modified Newton algorithm. By using well estimated initial shape the local minima can be avoided, which might appear when the nonlinear equation is solved with Newton algorithm. It is shown to be robust to noise in scattered fields via numerical examples by keeping only the propagating modes and filtering out the evanescent modes.

• 전자공학회논문지S
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• 제34S권8호
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• pp.84-91
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• 1997

The range image is divided into surface regions which are homogeneous in their intrinsic properties. In this paper, we use cooperative relaxational algorithm between curvatures to escape local minima and choose optimal possibility to reserve edge. Cooperative relaxational algorithm between curvatures is relaxation process in which weights of center pixel;s and neighbor pixel's possiblility are determined adaptively by using deviation of curvatures. Experimental resutls show that the proposed method segments and classifies the range images more accurately compared to the other relational algorithms.

• 천문학회보
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• 제41권1호
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• pp.78.3-78.3
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• 2016

The Kepler mission of NASA has enabled to discover a lot of new W UMa-type binaries with continuous light curves measured with unprecedented accuracy. Interestingly, their eclipsing time variation (hereafter ETV) diagrams show anti-correlation between primary and secondary minima, presumably occurred by continuous spot variation (Tran et al. 2013; Balaji et al. 2014). Two active Kepler binaries (KIC06118779 & KIC08682849), reported as showing the anti-correlation in ETV diagram, were investigated to see that the anti-correlations are correlated with time-variable O'connell effects appeared in their light curves. As a result, it was found that the O'connell effects for two binary stars have varied in quasi-sinusoidal ways similar to the patterns of their anti-correlation variations. In addition, our light curve syntheses of two binary stars with the latest version of the Wilson-Devinney code (Wilson & devinney 1971) show that they are very deep-contact binary system with extremely low mass ratios.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제13권4호
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• pp.254-268
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• 2013

For real-world clustering tasks, the input data is typically not easily separable due to the highly complex data structure or when clusters vary in size, density and shape. Kernel-based clustering has proven to be an effective approach to partition such data. In this paper, we provide an overview of several fuzzy kernel clustering algorithms. We focus on methods that optimize an fuzzy C-mean-type objective function. We highlight the advantages and disadvantages of each method. In addition to the completely unsupervised algorithms, we also provide an overview of some semi-supervised fuzzy kernel clustering algorithms. These algorithms use partial supervision information to guide the optimization process and avoid local minima. We also provide an overview of the different approaches that have been used to extend kernel clustering to handle very large data sets.