• 제목/요약/키워드: covariance function

검색결과 178건 처리시간 0.027초

기동하는 표적의 추적을 위한 연합형 가변차원 입력추정필터 (Federated Variable Dimension Kalman Filters with Input Estimation for Maneuvering Target Tracking)

  • 황보승욱;홍금식;최성린;최재원
    • 제어로봇시스템학회논문지
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    • 제5권6호
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    • pp.764-776
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    • 1999
  • In this paper, a tracking algorithm for a maneuvering single target in the presence of multiple data from multiple sensors is investigated. Allowing individual sensors to function by themselves, the estimates from individual sensors on the same target are fused for the purpose of improving the state estimate. The filtering method adopted in the local sensors is the variable dimensional filter with input estimatio technique, which consists of a constant velocity model and a constant acceleration model. A posteriori probability for the maneuvering hypothesis is newly derived. It is shown that the relation function of the a posteriori probability is a function of only the covariance of the fused estimates. Simulation results are provided.

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PCA와 입자 군집 최적화 알고리즘을 이용한 얼굴이미지에서 특징선택에 관한 연구 (A Study on Feature Selection in Face Image Using Principal Component Analysis and Particle Swarm Optimization Algorithm)

  • 김웅기;오성권;김현기
    • 전기학회논문지
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    • 제58권12호
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    • pp.2511-2519
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    • 2009
  • In this paper, we introduce the methodological system design via feature selection using Principal Component Analysis and Particle Swarm Optimization algorithms. The overall methodological system design comes from three kinds of modules such as preprocessing module, feature extraction module, and recognition module. First, Histogram equalization enhance the quality of image by exploiting contrast effect based on the normalized function generated from histogram distribution values of 2D face image. Secondly, PCA extracts feature vectors to be used for face recognition by using eigenvalues and eigenvectors obtained from covariance matrix. Finally the feature selection for face recognition among the entire feature vectors is considered by means of the Particle Swarm Optimization. The optimized Polynomial-based Radial Basis Function Neural Networks are used to evaluate the face recognition performance. This study shows that the proposed methodological system design is effective to the analysis of preferred face recognition.

시뮬레이션과 RSM을 이용한 시스템 최적화 과정에서 공통난수 활용에 따른 분산 분석 (Analysis of Variance for Using Common Random Numbers When Optimizing a System by Simulation and RSM)

  • 박진원
    • 한국시뮬레이션학회논문지
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    • 제10권4호
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    • pp.41-50
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    • 2001
  • When optimizing a complex system by determining the optimum condition of the system parameters of interest, we often employ the process of estimating the unknown objective function, which is assumed to be a second order spline function. In doing so, we normally use common random numbers for different set of the controllable factors resulting in more accurate parameter estimation for the objective function. In this paper, we will show some mathematical result for the analysis of variance when using common random numbers in terms of the regression error, the residual error and the pure error terms. In fact, if we can realize the special structure of the covariance matrix of the error terms, we can use the result of analysis of variance for the uncorrelated experiments only by applying minor changes.

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Assessment of speckle image through particle size and image sharpness

  • Qian, Boxing;Liang, Jin;Gong, Chunyuan
    • Smart Structures and Systems
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    • 제24권5호
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    • pp.659-668
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    • 2019
  • In digital image correlation, speckle image is closely related to the measurement accuracy. A practical global evaluation criterion for speckle image is presented. Firstly, based on the essential factors of the texture image, both the average particle size and image sharpness are used for the assessment of speckle image. The former is calculated by a simplified auto-covariance function and Gaussian fitting, and the latter by focusing function. Secondly, the computation of the average particle size and image sharpness is verified by numerical simulation. The influence of these two evaluation parameters on mean deviation and standard deviation is discussed. Then, a physical model from speckle projection to image acquisition is established. The two evaluation parameters can be mapped to the physical devices, which demonstrate that the proposed evaluation method is reasonable. Finally, the engineering application of the evaluation method is pointed out.

Prediction Intervals for LS-SVM Regression using the Bootstrap

  • Shim, Joo-Yong;Hwang, Chang-Ha
    • Journal of the Korean Data and Information Science Society
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    • 제14권2호
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    • pp.337-343
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    • 2003
  • In this paper we present the prediction interval estimation method using bootstrap method for least squares support vector machine(LS-SVM) regression, which allows us to perform even nonlinear regression by constructing a linear regression function in a high dimensional feature space. The bootstrap method is applied to generate the bootstrap sample for estimation of the covariance of the regression parameters consisting of the optimal bias and Lagrange multipliers. Experimental results are then presented which indicate the performance of this algorithm.

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An Alternative Proof of the Asymptotic Behavior of GLSE in Polynomial MEM

  • Myung-Sang Moon
    • Communications for Statistical Applications and Methods
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    • 제3권3호
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    • pp.75-81
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    • 1996
  • Polynomial measurement error model(MEM) with one predictor is considered. It is briefly mentioned that Chan and Mak's generalized least squares estimator(GLSE) can be derived more easily if Hermite polynomial concept is applied. It is proved that GLSE derived using new procedure is equivalent to the estimator obtained from corrected score function. Finally, much simpler proof of the asymptotic behavior of GLSE than that of Chan and Mak is provided. Much simpler formula of asymptotic covariance matrix of GLSE is a part of that proof.

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시공간 베이지안 계층모형-미국 연기온 편차자료에 적용-

  • 이의규;문명상
    • 한국통계학회:학술대회논문집
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    • 한국통계학회 2002년도 추계 학술발표회 논문집
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    • pp.163-168
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    • 2002
  • 전형적인 시공간모형은 시공간 변이도(semivariogram) 또는 공분산 함수(covariance function)를 필요로 한다. 본 논문에서는 계산하기 어렵고 현실적이지 못한 결합 공분산함수를 통한 고전적 모형 대신, 일련의 독립적인 조건분포를 이용하는 보다 현실적인 베이지안 계층모형을 이용한다. 미국 전 지역에 산재해 있는 138개 기온 관측소로부터 얻어진 61년(1920-1980) 동안의 연기온편차 자료에 시공간 베이지안 계층모형을 적용하고 순수시계열모형에서의 적합값과 제안된 모형의 적합값을 비교분석한다.

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A Note on Possibilistic Correlation

  • Hong, Dug-Hun
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • 제9권1호
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    • pp.1-3
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    • 2009
  • Recently, Carlsson, Full\acute{e}$r and Majlender [1] presented the concept of possibilitic correlation representing an average degree of interaction between marginal distribution of a joint possibility distribution as compared to their respective dispersions. They also formulated the weak and strong forms of the possibilistic Cauchy-Schwarz inequality. In this paper, we define a new probability measure. Then the weak and strong forms of the Cauchy-Schwarz inequality are immediate consequence of probabilistic Cauchy-Schwarz inequality with respect to the new probability measure.

Sequential Confidence Set of the Mean Vector of a Multivariate Distribution

  • Kim, Sung Lai
    • 충청수학회지
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    • 제5권1호
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    • pp.87-97
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    • 1992
  • Sequential procedure with ${\beta}$-protection for the mean vector ${\mu}(\theta)$ of a p(> 1)-variate multivariate distribution $P_{\theta}$, ${\theta}{\in}{\Theta}$, with covariance matrix ${\sum}(\theta)$ is considered when the only nuisance parameters is ${\sum}(\theta)$. We obtain a confidence set for ${\mu}(\theta)$ with coverage probability condition and ${\beta}$-protection at ${\mu}-{\delta}(\mu)$ for some imprecision function ${\delta}:\mathbb{R}^p{\rightarrow}\mathbb{R}^p$.

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시변 측정잡음 모델을 고려한 실시간 시선각 변화율 추정필터 (A Practical Real-Time LOS Rate Estimator with Time-Varying Measurement Noise Variance)

  • 나원상;이진익
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2003년도 하계학술대회 논문집 D
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    • pp.2082-2084
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    • 2003
  • A practical real-time LOS rate estimator is proposed to handle the time-varying measurement noise statistics. To calculate the optimal Kalman gain, the algebraic transformation method is taken into account. By using the algebraic transformation, the differential algebraic Riccati equation(DARE) regarding estimation error covariance is replaced by the simple algebraic Riccati equation(ARE). The proposed LOS estimation filter gain is only a function of relative range. Consequently, the proposed method is computationally very efficient and suitable for embedded environment.

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