• Title/Summary/Keyword: Second-order correlation function

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Moving Pixel Displacement Detection using Correlation Functions on CIS Image

  • Ryu, Kwang-Ryol;Kim, Young-Bin
    • Journal of information and communication convergence engineering
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    • v.8 no.4
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    • pp.349-354
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    • 2010
  • Moving pixel displacement detection algorithm using correlation functions for making panorama image on the continuous images is presented in this paper. The input images get from a CMOS image sensor (CIS). The camera is maintained by constant brightness and uniform sensing area in test input pattern. For simple navigation and capture image has to 70% overlapped region. A correlation rate in two image data is evaluated by using reference image with first captures, and compare image with next captures. The displacement of the two images are expressed to second order function of x, y and solved with finding the coefficient in second order function. That results in the change in the peak correlation displacement from the reference to the compare image, is moving to pixel length. The navigating error is reduced by varying the path because the error is shown in the difference of the positioning vector between the true pixel position and the navigated pixel position. The algorithm performance is evaluated to be different from the error vector to vary the navigating path grid.

2차원 음향 .광 변조기를 이용한 실시간 3차 상관기

  • 장경영;오재응
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.04a
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    • pp.208-212
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    • 1993
  • Third order correlation function is to be advantageous to detect unique features embedded in various random signals that are undtectable with second order correlation or power spectrum. In order paper, we will introduce a real time third order correlator which consists of a laser light source, an acousto-optical modulator with signal controlling circuitry, and a CCD camera connected to computer for image processing. With this correlator, the third order correlation pattern of a signal can be immediately obtained at the camera due to parallelnature of optical computing.

A Study on the Effective Hydraulic Conductivity of an Anisotropic Porous Medium

  • Seong, Kwanjae
    • Journal of Mechanical Science and Technology
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    • v.16 no.7
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    • pp.959-965
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    • 2002
  • Effective hydraulic conductivity of a statistically anisotropic heterogeneous medium is obtained for steady two-dimensional flows employing stochastic analysis. Flow equations are solved up to second order and the effective conductivity is obtained in a semi-analytic form depending only on the spatial correlation function and the anisotropy ratio of the hydraulic conductivity field, hence becoming a true intrinsic property independent of the flow field. Results are obtained using a statistically anisotropic Gaussian correlation function where the anisotropy is defined as the ratio of integral scales normal and parallel to the mean flow direction. Second order results indicate that the effective conductivity of an anisotropic medium is greater than that of an isotropic one when the anisotropy ratio is less than one and vice versa. It is also found that the effective conductivity has upper and lower bounds of the arithmetic and the harmonic mean conductivities.

The Effect of External Noise on Dynamic Behaviors of the Schlogl Model with the Second Order Transition for a Photochemical Reaction

  • 김경란;Lee, Dong J.;신국조
    • Bulletin of the Korean Chemical Society
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    • v.16 no.11
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    • pp.1119-1121
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    • 1995
  • The method for the Schlo"gl model with the first order transition is extended to the Scho;gl model with the second order transition for a photochemical reaction. We obtain the explicit results of the time-dependent average and the time correlation function at the unstable steady state of the model in the neighborhood of the Gaussian white noise and then discuss the effect of noise on the dynamic properties.

Edge Enhanced Error Diffusion based on Gradient Shaping of Original Image (원영상의 기울기 성형을 이용한 경계강조 오차확산법)

  • 강태하
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.25 no.10B
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    • pp.1832-1840
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    • 2000
  • The error diffusion algorithm is good for reproducing continuous images to binary images. However the reproduction of edge characteristics is weak in power spectrum an analysis of display error. In this paper an edge enhanced error diffusion method is proposed to improve the edge characteristic enhancement. Spatial gradient information in original image is adapted for edge enhance in threshold modulation of error diffusion. First the horizontal and vertical second order differential values are obtained from the gradient of peripheral pixels(3x3) in original image. second weighting function is composed by function including absolute value and sign of second order differential values. The proposed method presents a good visual results which edge characteristics is enhanced. The performance of the proposed method is compared with that of the conventional edge enhanced error diffusion by measuring the edge correlation and the local average accordance over a range of viewing distances and the RAPSD of display error.

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Acousto-Optical Third Order Correlator Using 2-D Ultrasonic Diffractor Cell (2차원 초음파 회절격자를 이용한 음향-광3차 상관기의 구성)

  • Jang, Gyeong-Yeong;Sato, Takuso
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.1
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    • pp.206-213
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    • 1996
  • Third order correlation funciton is to be advantageous to detect unique features embedded in various random signals that are undetectable with second order correlation or power spectrum. In this paper, we will introduce optical modulator which consists of a laser light source, 2-dimensional ultrasonic diffractor cell with signal controlling circuitry, and a CCD camera connected to personal computer for image processing. With this modulator, the third order correlaiton pattern of signal can be immediately obtained at the camera due to parallel nature of optical computing.

Free vibration analysis of rotating beams with random properties

  • Hosseini, S.A.A.;Khadem, S.E.
    • Structural Engineering and Mechanics
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    • v.20 no.3
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    • pp.293-312
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    • 2005
  • In this paper, free vibration of rotating beam with random properties is studied. The cross-sectional area, elasticity modulus, moment of inertia, shear modulus and density are modeled as random fields and the rotational speed as a random variable. To study uncertainty, stochastic finite element method based on second order perturbation method is applied. To discretize random fields, the three methods of midpoint, interpolation and local average are applied and compared. The effects of rotational speed, setting angle, random property variances, discretization scheme, number of elements, correlation of random fields, correlation function form and correlation length on "Coefficient of Variation" (C.O.V.) of first mode eigenvalue are investigated completely. To determine the significant random properties on the variation of first mode eigenvalue the sensitivity analysis is performed. The results are studied for both Timoshenko and Bernoulli-Euler rotating beam. It is shown that the C.O.V. of first mode eigenvalue of Timoshenko and Bernoulli-Euler rotating beams are approximately identical. Also, compared to uncorrelated random fields, the correlated case has larger C.O.V. value. Another important result is, where correlation length is small, the convergence rate is lower and more number of elements are necessary for convergence of final response.

Generalization of Recurrent Cascade Correlation Algorithm and Morse Signal Experiments using new Activation Functions (순환 케스케이드 코릴레이션 알고리즘의 일반화와 새로운 활성화함수를 사용한 모스 신호 실험)

  • Song Hae-Sang;Lee Sang-Wha
    • Journal of Intelligence and Information Systems
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    • v.10 no.2
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    • pp.53-63
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    • 2004
  • Recurrent-Cascade-Correlation(RCC) is a supervised teaming algorithm that automatically determines the size and topology of the network. RCC adds new hidden neurons one by one and creates a multi-layer structure in which each hidden layer has only one neuron. By second order RCC, new hidden neurons are added to only one hidden layer. These created neurons are not connected to each other. We present a generalization of the RCC Architecture by combining the standard RCC Architecture and the second order RCC Architecture. Whenever a hidden neuron has to be added, the new RCC teaming algorithm automatically determines whether the network topology grows vertically or horizontally. This new algorithm using sigmoid, tanh and new activation functions was tested with the morse-benchmark-problem. Therefore we recognized that the number of hidden neurons was decreased by the experiments of the RCC network generalization which used the activation functions.

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Statistical Characteristics of Pollutants in Sterm Flow (하천오염인자의 통계적 특성)

  • 황임구;윤태훈
    • Water for future
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    • v.14 no.4
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    • pp.19-26
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    • 1981
  • The auto-and cross-correlation function, power spectrum, coherence function and Markov model are applied to investigate the statistical characteristics of discharge and each factor of water quality and the interrelation-ship between the variation of discharge and water quality factors. The analysis of discharge, dissolved oxygen and electric conductivity, which were only obtainable data at the Indogyo gagining station in the downstream of the Han River, clearly showed that they hace distinct period of 12 months and three different periods of 6, 4 and 3 months weaker than the former. The cross-correlation between the discharge and water quality(DO, COND) is rather weak and the crosscorrelation function has its peak at lag one. It is considered therefrom that the variation of discharge behaves on water quality facotrs with one day's difference. In the examination of linear regression model for the serial generation and predictive measures, discharge series is fit to first and second order Markov model and DO, COND to first order Markov model.

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Identification of Volterra Kernels of Nonlinear Van de Vusse Reactor

  • Kashiwagi, Hiroshi;Rong, Li
    • 제어로봇시스템학회:학술대회논문집
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    • 2001.10a
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    • pp.26.3-26
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    • 2001
  • Van de Vusse reactor is known as a highly nonlinear chemical process and has been considered by a number of researchers as a benchmark problem for nonlinear chemical process. Various identification methods for nonlinear system are also verified by applying these methods to Van de Vusse reactor. From the point of view of identification, only the Volterra kernel of second order has been obtained until now. In this paper, the authors show that Volterra kernels of nonlinear Van de Vusse reactor of up to 3rd order are obtained by use of M-sequence correlation method. A pseudo-random M-sequence is applied to Van de Vusse reactor as an input and its output is measured. Taking the cross correlation function between the input and the output, we obtain up to 3rd order Volterra kernels, which is ...

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