• Title/Summary/Keyword: curvature estimation

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ACC/AEBS 시스템용 센서퓨전을 통한 주행경로 추정 알고리즘 (Development of the Driving path Estimation Algorithm for Adaptive Cruise Control System and Advanced Emergency Braking System Using Multi-sensor Fusion)

  • 이동우;이경수;이재완
    • 자동차안전학회지
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    • 제3권2호
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    • pp.28-33
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    • 2011
  • This paper presents driving path estimation algorithm for adaptive cruise control system and advanced emergency braking system using multi-sensor fusion. Through data collection, yaw rate filtering based road curvature and vision sensor road curvature characteristics are analyzed. Yaw rate filtering based road curvature and vision sensor road curvature are fused into the one curvature by weighting factor which are considering characteristics of each curvature data. The proposed driving path estimation algorithm has been investigated via simulation performed on a vehicle package Carsim and Matlab/Simulink. It has been shown via simulation that the proposed driving path estimation algorithm improves primary target detection rate.

Curvature Estimation을 이용한 3차원 사람얼굴 세그멘테이션 (3D Human Face Segmentation using Curvature Estimation)

  • Seongdong Kim;Seonga Chin;Moonwon Choo
    • 한국멀티미디어학회논문지
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    • 제6권6호
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    • pp.985-990
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    • 2003
  • 본 논문에서는 3차원 사람얼굴의 굴곡표면에 대하여 특징 값들을 추출하여 회전벡터를 이용하여 회전한 후 그들을 분석, 표현하는 방법을 제안한다. 또한 실험을 통하여 정확하게 추출된 굴곡표면의 특징 값들은 3차원 사람얼굴을 세그멘테이션 하는데 적용되었다 사람얼굴의 표면은 메쉬(mesh)모델을 사용하여 파라메타를 계산, 추출하였으며, 추출된 특징 값들은 얼굴표면을 Gaussian과 Mean 곡면 분류표(classification)를 사용하여 임계 값을 사용하지 않고 3D 얼굴표면을 세그멘테이션 하였다.

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IDRS 시스템에서 Curve Fitting이 적용된 NLS 비용함수를 이용한 방위/거리 추정 기법 (Bearing/Range Estimation Method using NLS Cost Function in IDRS System)

  • 정태진;김대경;권범수;윤경식;이균경
    • 한국군사과학기술학회지
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    • 제14권4호
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    • pp.590-597
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    • 2011
  • The IDRS provides detection, classification and bearing/range estimation by performing wavefront curvature analysis on an intercepted active transmission from target. Especially, a estimate of the target bearing/range that significantly affects the optimal operation of own submarine is required. Target bearing/range can be estimated by wavefront curvature ranging which use the difference of time arrival at sensors. But estimation ambiguity occur in bearing/range estimation due to a number of peaks caused by high center frequency and limited bandwidth of the intercepted active transmission and distortion caused by noise. As a result the bearing/range estimation performance is degraded. To estimate target bearing/range correctly, bearing/range estimation method that eliminate estimation ambiguity is required. In this paper, therefore, for wavefront curvature ranging, NLS cost function with curve fitting method is proposed, which provide robust bearing/range estimation performance by eliminating estimation ambiguity. Through simulation the performance of the proposed bearing/range estimation methods are verified.

Performance Evaluation of New Curvature Estimation Approaches (Performance evaluation of new curvature estimation approaches)

  • 손광훈
    • 한국통신학회논문지
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    • 제22권5호
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    • pp.881-888
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    • 1997
  • The existing method s for curvature estimation have a common problem in determining a unique smoothong factor. we previously proposed two approaches to overcome that problem: a constrained regularization approach and a mean field annealing approach. We consistently detected corners from the perprocessed smooth boundary obtained by either the constrained eglarization approach or the mean field annealing approach. Moreover, we defined corner sharpness to increase the robustness of both approaches. We evaluate the performance of those methods proposed in this paper. In addition, we show some matching results using a two-dimensional Hopfield neural network in the presence of occlusion as a demonstration of the power of our proposed methods.

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해저면 반사 환경에서 음파의 파면을 이용하는 음원의 거리 추정 (Estimation of a source range using acoustic wavefront in bottom reflection environment)

  • 박정수;박중용;손수욱;배호석
    • 한국음향학회지
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    • 제43권3호
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    • pp.324-334
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    • 2024
  • 파면곡률거리추정(Wavefront Curvature Ranging, WCR)은 음파의 파면곡률로부터 음원의 거리를 추정하는 방법이다. 기존의 파면곡률거리추정은 음속을 상수로 가정하고 삼각법으로 거리를 추정한다. 이 가정 때문에 해저면반사경로가 뚜렷하게 분리되는 해양환경에서는 거리 오차가 발생한다. 거리 오차를 줄이기 위해 해양의 음속구조를 적용하고 최대우도추정(Maximum Likelihood Estimation, MLE)방법으로 거리를 추정하는 정합 파면곡률거리추정(Matched Wavefront Curvature Ranging, MWCR) 을 제안하였다. 정합 파면곡률거리추정의 시뮬레이션 결과로부터 거리 오차의 감소를 확인하였다. 향후에 실측 신호로부터 거리 추정의 신뢰성을 확인하면 소나 시스템에 적용 가능할 것이다.

COMPARISON THEOREMS IN FINSLER GEOMETRY WITH WEIGHTED CURVATURE BOUNDS AND RELATED RESULTS

  • Wu, Bing-Ye
    • 대한수학회지
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    • 제52권3호
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    • pp.603-624
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    • 2015
  • We first extend the notions of weighted curvatures, including the weighted flag curvature and the weighted Ricci curvature, for a Finsler manifold with given volume form. Then we establish some basic comparison theorems for Finsler manifolds with various weighted curvature bounds. As applications, we obtain some McKean type theorems for the first eigenvalue of Finsler manifolds, some results on weighted curvature and fundamental group for Finsler manifolds, as well as an estimation of Gromov simplicial norms for reversible Finsler manifolds.

Effects of curvature on leverage in nonlinear regression

  • Kahng, Myung-Wook
    • Journal of the Korean Data and Information Science Society
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    • 제20권5호
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    • pp.913-917
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    • 2009
  • The measures of leverage in linear regression has been extended to nonlinear regression models. We consider several curvature measures of nonlinearity in an estimation situation. The relationship between measures of leverage and statistical curvature are explored in nonlinear regression models. The circumstances under which the Jacobian leverage reduces to a tangent plane leverage are discussed in connection with the effective residual curvature of the nonlinear model.

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L-curve를 이용한 광학 흐름 추정을 위한 정규화 매개변수 결정 (Regularization Parameter Determination for Optical Flow Estimation using L-curve)

  • 김종대;김종원
    • 정보처리학회논문지B
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    • 제14B권4호
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    • pp.241-248
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    • 2007
  • 본 논문은 광학 흐름을 추정하는데 있어서 최적 정규화 매개변수를 결정하기 위한 L-curve 모서리 검출 방법을 제안한다. 기존의 곡률법은 L-curve의 곡률 그래프에서 최대 위치를 찾는 반면, 제안한 방법은 바로 우측 음의 계곡과의 곡률 차가 최대가 되는 양의 봉우리의 위치를 찾아서 매개변수 값을 결정한다. 이 방법으로 선정한 매개변수로 광학 흐름을 추정하면, 평균적으로 최소 오차로부터 단지 0.02 pixel/frame 차이가 나는 것이 실험을 통하여 보여진다. 또한 제안한 방법으로 기존의 모서리 검출법인 곡률법이나 적응 제거법에 비해 최소 오차에 가장 가까운 광학 흐름을 구할 수 있었다.

인공신경망을 적용한 선상가열시 강판의 곡률변형 추정 (Application of Neural Network to the Estimation of Curvature Deformation of Steel Plates in Line Heating)

  • 전병재;김현준;양박달치
    • 한국해양공학회지
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    • 제20권4호
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    • pp.24-30
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    • 2006
  • Different methods exist for the estimation of thermaldeformation of plates in the line heating process. These are based on the assumption of residual strains in the heat-affected zone, known as the method of inherent strains, or simulated relations between heating conditions and residual deformations. The purpose of this paper is to develop a simulator of thermal deformation in the line heating, using the artificial neural network. Curvature deformations for the plate-forming are investigated, which can be used as a prime deformation parameter in the process. The curvature of plates are calculated using the approximation of plate surface by NURBS. Line heating experiments for 11 specimens of different thickness and heating conditions were performed. Two neural networks predicting the maximum temperature and curvature deformations at the heating line are studied. It was concluded that the thermal deformations predicted by the neural network can be used in a line heating simulator, which is considered an attractive and practical alternative to the existing methods.