• Title/Summary/Keyword: outliers

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Skew Normal Boxplot and Outliers

  • Huh, Myung-Hoe;Lee, Yong-Goo
    • Communications for Statistical Applications and Methods
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    • v.19 no.4
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    • pp.591-595
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    • 2012
  • We frequently use Tukey's boxplot to identify outliers in the batch of observations of the continuous variable. In doing so, we implicitly assume that the underlying distribution belongs to the family of normal distributions. Such a practice of data handling is often superficial and improper, since in reality too many variables manifest the skewness. In this short paper, we build a modified boxplot and set the outlier identification procedure by assuming that the observations are generated from the skew normal distribution (Azzalini, 1985), which is an extension of the normal distribution. Statistical performance of the proposed procedure is examined with simulated datasets.

Robust Estimation of Camera Parameters from Video Signals for Video Composition (영상합성을 위한 영상으로부터의 견실한 카메라피라미터 확정법)

  • 박종일;이충웅
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.32B no.10
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    • pp.1305-1313
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    • 1995
  • In this paper, we propose a robust estimation of camera parameters from image sequence for high quality video composition. We first establish correspondence of feature points between consecutive image fields. After the establishment, we formulate a nonlinear least-square data fitting problem. When the image sequence contains moving objects, and/or when the correspondence establishment is not successful for some feature points, we get bad observations, outliers. They should be properly eliminated for a good estimation. Thus, we propose an iterative algorithm for rejecting the outliers and fitting the camera parameters alternatively. We show the validity of the proposed method using computer generated data sets and real image sequeces.

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A Novel Battery State of Health Estimation Method Based on Outlier Detection Algorithm

  • Piao, Chang-hao;Hu, Zi-hao;Su, Ling;Zhao, Jian-fei
    • Journal of Electrical Engineering and Technology
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    • v.11 no.6
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    • pp.1802-1811
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    • 2016
  • A novel battery SOH estimation algorithm based on outlier detection has been presented. The Battery state of health (SOH) is one of the most important parameters that describes the usability state of the power battery system. Firstly, a battery system model with lifetime fading characteristic was established, and the battery characteristic parameters were acquired from the lifetime fading process. Then, the outlier detection method based on angular distribution was used to identify the outliers among the battery behaviors. Lastly, the functional relationship between battery SOH and the outlier distribution was obtained by polynomial fitting method. The experimental results show that the algorithm can identify the outliers accurately, and the absolute error between the SOH estimation value and true value is less than 3%.

A Comparision on CERES & Robust-CERES

  • Oh, Kwang-Sik;Do, Soo-Hee;Kim, Dae-Hak
    • 한국데이터정보과학회:학술대회논문집
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    • 2003.10a
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    • pp.93-100
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    • 2003
  • It is necessary to check the curvature of selected covariates in regression diagnostics. There are various graphical methods using residual plots based on least squares fitting. The sensitivity of LS fitting to outliers can distort their residuals, making the identification of the unknown function difficult to impossible. In this paper, we compare combining conditional expectation and residual plots(CERES Plots) between least square fit and robust fits using Huber M-estimator. Robust CERES will be far less distorted than their LS counterparts in the presence of outliers and hence, will be more useful in identifying the unknown function.

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Genetic Outlier Detection for a Robust Support Vector Machine

  • Lee, Heesung;Kim, Euntai
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.15 no.2
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    • pp.96-101
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    • 2015
  • Support vector machine (SVM) has a strong theoretical foundation and also achieved excellent empirical success. It has been widely used in a variety of pattern recognition applications. Unfortunately, SVM also has the drawback that it is sensitive to outliers and its performance is degraded by their presence. In this paper, a new outlier detection method based on genetic algorithm (GA) is proposed for a robust SVM. The proposed method parallels the GA-based feature selection method and removes the outliers that would be considered as support vectors by the previous soft margin SVM. The proposed algorithm is applied to various data sets in the UCI repository to demonstrate its performance.

Outliers Identification and Reliabilities in Geodetic Networks (돌출오차(突出誤差)의 검출(檢出)과 측지망(測地網)의 신뢰도(信賴度))

  • Lee, Suck Chan;Kho, Young Ho;Lee, Young Jin
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.7 no.1
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    • pp.1-9
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    • 1987
  • This paper is mainly concerned with the analysis of post-adjustment techniques for the outliers identification and reliabilities in geodetic networks. The proposed strategy which easily attached to a least squares adjustment program, is successfully used in a test network. It shows that their application can considerably improve the quality of the results, but the main advantage appears when their reliability is considered.

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Robust Fuzzy Varying Coefficient Regression Analysis with Crisp Inputs and Gaussian Fuzzy Output

  • Yang, Zhihui;Yin, Yunqiang;Chen, Yizeng
    • Journal of Computing Science and Engineering
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    • v.7 no.4
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    • pp.263-271
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    • 2013
  • This study presents a fuzzy varying coefficient regression model after deleting the outliers to improve the feasibility and effectiveness of the fuzzy regression model. The objective of our methodology is to allow the fuzzy regression coefficients to vary with a covariate, and simultaneously avoid the impact of data contaminated by outliers. In this paper, fuzzy regression coefficients are represented by Gaussian fuzzy numbers. We also formulate suitable goodness of fit to evaluate the performance of the proposed methodology. An example is given to demonstrate the effectiveness of our methodology.

Temporal matching prior network for vehicle license plate detection and recognition in videos

  • Yoo, Seok Bong;Han, Mikyong
    • ETRI Journal
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    • v.42 no.3
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    • pp.411-419
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    • 2020
  • In real-world intelligent transportation systems, accuracy in vehicle license plate detection and recognition is considered quite critical. Many algorithms have been proposed for still images, but their accuracy on actual videos is not satisfactory. This stems from several problematic conditions in videos, such as vehicle motion blur, variety in viewpoints, outliers, and the lack of publicly available video datasets. In this study, we focus on these challenges and propose a license plate detection and recognition scheme for videos based on a temporal matching prior network. Specifically, to improve the robustness of detection and recognition accuracy in the presence of motion blur and outliers, forward and bidirectional matching priors between consecutive frames are properly combined with layer structures specifically designed for plate detection. We also built our own video dataset for the deep training of the proposed network. During network training, we perform data augmentation based on image rotation to increase robustness regarding the various viewpoints in videos.

On the Efficiency of Outlier Cleaners in Spatial Data Analysis (공간통계분석에서 이상점 수정방법의 효율성비교)

  • 이진희;신기일
    • The Korean Journal of Applied Statistics
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    • v.17 no.2
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    • pp.327-336
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    • 2004
  • Many researchers have used the robust variogram to reduce the effect of outliers in spatial data analysis. Recently it is known that estimating the variogram after replacing outliers is more efficient. In this paper, we suggest a new data cleaner for geostatistic data analysis and compare the efficiency of outlier cleaners.

Power Spectrum Estimation of EEG Signal Using Robust Filter (로버스트 필터를 이용한 EEG 신호의 스펙트럼 추정)

  • 김택수;허재만
    • Journal of Biomedical Engineering Research
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    • v.13 no.2
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    • pp.125-132
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    • 1992
  • Background EEG signals can be represented as the sum of a conventional AR process and an innovation process. It Is know that conventional estimation techniques, such as least square estimates (LSE) or Gaussian maximum likelihood estimates (MLE-G ) are optimal when the innovation process satisfies the Gaussian or presumed distribution. When the data are contaminated by outliers, however, these assumptions are not met and the power spectrum estimated by conventional estimation techniques may be fatally biased. EEG signal may be affected by artifacts, which are outliers in the statistical term. So the robust filtering estimation technique is used against those artifacts and it performs well for the contaminated EEG signal.

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