• 제목/요약/키워드: HUBER

검색결과 78건 처리시간 0.02초

A Comparision on CERES & Robust-CERES

  • 오광식;도수희;김대학
    • 한국데이터정보과학회:학술대회논문집
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    • 한국데이터정보과학회 2003년도 추계학술대회
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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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충격성 잡음에 강인한 가변 망각인자 칼만 시변 주파수 추정기법 (Kalman based time-varying Spectral estimation using Variable Forgetting Factor robust to impulsive noise)

  • 김한수
    • 한국음향학회:학술대회논문집
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    • 한국음향학회 1998년도 학술발표대회 논문집 제17권 2호
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    • pp.165-168
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    • 1998
  • 본 논문에서는 충격성 잡음에 강인하기 위한 시변 주파수 추정 기법을 제안하였다 충격성 잡음에 강인하기 위해서는 충격성 잡음에 의한 추정 변수의 동요를 제한하고 추정된 오차가 향후 추정시 영향을 미치는 오차의 전파현상을 제한하여야 한다. 충격성 잡음에 의한 추정오차의 전파를 제한하기 위해서는 망각인자의 도입이 필요함을 증명하였고 보다 효과적으로 사용하기 위해서 가변 망각인자를 도입하였다. 가변 망각인자의 도입으로 충격성 잡음에 의한 오차의 전파를 선택적으로 제한할 수 있으며 충격성 잡음에 의한 추정계수의 변동은 영향함수 측면에서 Huber함수를 이용하여 제한하였다. 제안된 알고리듬은 Huber함수와 가변망각인자의 도입으로 충격성 잡음에 의해 생기는 오차의 크기와 오차의 영향이 전파되는 것을 적응적으로 제한하기 때문에 모의실험을 통해 기존의 칼만 알고리듬보다 나은 성능을 보임을 알 수 있었다.

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공정평균을 관리하기 위한 로버스트 관리도 (Robust Control Chart for the Control of the Process Mean)

  • 이병근;정현석;남호수
    • 산업경영시스템학회지
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    • 제21권48호
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    • pp.65-71
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    • 1998
  • Control chart is a very extensively used tool in testing whether a process is in a state of statistical control or not. In this paper, a robust control chart for variables is proposed, which is based on the Huber's M-estimator. The Huber's M-estimator is a well-known robust estimator in sense of distributional robustness. In the proposed chart, the estimation of the process deviation is modified to have a stable level and high power. To compare the performances of the proposed control chart with the classical (equation omitted), some Monte Carlo simulations are performed. The simulation results show that the robust control chart has good performance.

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On an Analytical Quick Game to Investigate the Battle Effectiveness of Forward Defence Concepts

  • Huber, Reiner K.;Steiger, Karl;Wobith, Bernt
    • 한국경영과학회지
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    • 제6권1호
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    • pp.33-55
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    • 1981
  • The so-called “Quick Game”-models resemble a central element within the Compound Gaming approach of military systems analysis proposed by Huber [1, 2]. This paper introduces such an analytical model designed to investigate the battle-effectiveness of alternative army structures. The nature of its results is discussed from numerical experiments covering the (German) Army Structure 4, Loser's Area Coverage Defence Concept, and Afheldt's Area Defence Concept. It turns out that Loser's concept promises to have a comparatively high potential to stabilize the early conventional forward defence, hence being an interesting alternative for further analysis in depth.

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Hybrid L1/L2 를 이용한 주파수 영역 탄성파 파형역산 (Robust seismic waveform inversion using backpropagation algorithm)

  • 정우근;하태영;신창수
    • 한국지구물리탐사학회:학술대회논문집
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    • 한국지구물리탐사학회 2007년도 공동학술대회 논문집
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    • pp.124-129
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    • 2007
  • For seismic imaging and inversion, the inverted image depends on how we define the objective function. ${\ell}^1$-norm is more robust than ${\ell}^2$-norm. However, it is difficult to apply the Newton-type algorithm directly because the partial derivative for ${\ell^1$-norm has a singularity. In our paper, to overcome the difficulties of singularities, Huber function given by hybrid ${\ell}^1/{\ell}^2$-norm is used. We tested the robustness of our new object function with several noisy data set. Numerical results show that the new objective function is more robust to band limited spiky noise than the conventional object function.

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소실점 정보의 Loss 함수를 이용한 특징선 기반 SLAM (Line-Based SLAM Using Vanishing Point Measurements Loss Function)

  • 임현준;명현
    • 로봇학회논문지
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    • 제18권3호
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    • pp.330-336
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    • 2023
  • In this paper, a novel line-based simultaneous localization and mapping (SLAM) using a loss function of vanishing point measurements is proposed. In general, the Huber norm is used as a loss function for point and line features in feature-based SLAM. The proposed loss function of vanishing point measurements is based on the unit sphere model. Because the point and line feature measurements define the reprojection error in the image plane as a residual, linear loss functions such as the Huber norm is used. However, the typical loss functions are not suitable for vanishing point measurements with unbounded problems. To tackle this problem, we propose a loss function for vanishing point measurements. The proposed loss function is based on unit sphere model. Finally, we prove the validity of the loss function for vanishing point through experiments on a public dataset.

Extracts of Centaurea bornmuelleri and Centaurea huber-morathii inhibit the growth of colon cancer cells in vitro

  • Sarker, Satyajit Dey;Shoeb, Mohammad;Celik, Sezgin;Jaspars, Marcel;Nahar, Lutfun;Kong-Thoo-Lin, Paul;MacManus, Stephen M
    • Advances in Traditional Medicine
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    • 제7권4호
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    • pp.336-340
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    • 2007
  • Plants from the genus Centaurea (C.) (Family: Asteraceae alt. Compositae), widely distributed in Asia, Europe and North America, have traditionally been used in the treatment of various ailments. As a part of our on-going studies on the plants from the genus C. for their phytochemistry and biological activities, extracts of the seeds of Turkish endemic C. species, C. bornmuelleri and C. huber-morathii, were tested for their cytotoxicity towards the CaCo2 colon cancer cell line as well as for the toxicity towards the brine shrimps, using the MTT and the brine shrimp lethality assays, respectively. Among the extracts, the MeOH extract of these plants showed significant toxicity towards the brine shrimps ($LD_{50}=55.2{\times}10^{-2}\;and\;42.4{\times}10^{-2}mg/ml$, respectively). The MeOH extract of both C. species also inhibited the growth of CaCo2 colon cancer cells in the MTT assay ($IC_{50}$=29.9 and 33.0 g/ml, respectively). As the most prominent activities in both assays were observed with the MeOH extracts, it can be assumed that the compound(s) responsible for these activities are polar in nature.

Antibacterial and antioxidant activities of three Turkish species of the genus Centaurea

  • Sarker, Satyajit Dey;Kumarasamy, Yashodharan;Shoeb, Mohammad;Celik, Sezgin;Eucel, Ersin;Middleton, Moira;Nahar, Lutfun
    • Advances in Traditional Medicine
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    • 제5권3호
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    • pp.246-250
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    • 2005
  • A number of species of the genus Centaurea (Family: Asteraceae), distributed in various parts of Asia, Europe and North America, have been used in traditional plant-based medicine and reported to possess various medicinal properties. As part of our continuing evaluation of plants from the genus Centaurea for their phytochemistry and biological activities, the dichloromethane (DCM) and methanol (MeOH) extracts of the seeds of Turkish Centaurea species, C. bornmuelleri, C. huber-morathii and C. schiskinii, were screened for antioxidant and antibacterial activities. Among the three species, C. huber-morathii displayed the most prominent antibacterial activity. Both the MeOH and DCM extracts of this plant showed activity against Citrobacter freundii, Enterococcus faecalis and Salmonella goldcoast with the MIC values within the range of $1\;{\times}\;10^{-2}\;to\;1\;{\times}\;10^{-3}\;mg/ml$. The MeOH extract of C schiskinii showed activity $(MIC\;=\;1\;{\times}\;10^{-1}\;mg/ml)$ against Citrobacter freundii and Staphylococcus aureus. While the DCM extract of C. bornmuelleri was only active against Staphylococcus aureus $(MIC\;=1\;{\times}\;10^{-2}\;mg/ml)$, the MeOH extract did not show any inhibitory activity at test concentrations. The DCM and MeOH extracts of all three species demonstrated good degree of antioxidant property in the DPPH assay with the $RC_{50}$ values ranging from $72\;{\times}\;10^{-2}\;to\;31{\times}\;10^{-3}\;mg/ml$. Among these extracts, the MeOH extract of C. hubermorathii was the most active antioxidant extract $(MlC\;=\;31\;{\times}\;10^{-3}\;mg/ml)$.