• 한국지구과학회지
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• 제26권2호
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• pp.114-128
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• 2005

Fuzzy information representation of multi-source spatial data is applied to landslide hazard mapping. Information representation based on frequency ratio and non-parametric density estimation is used to construct fuzzy membership functions. Of particular interest is the representation of continuous data for preventing loss of information. The non-parametric density estimation method applied here is a Parzen window estimation that can directly use continuous data without any categorization procedure. The effect of the new continuous data representation method on the final integrated result is evaluated by a validation procedure. To illustrate the proposed scheme, a case study from Jangheung, Korea for landslide hazard mapping is presented. Analysis of the results indicates that the proposed methodology considerably improves prediction capabilities, as compared with the case in traditional continuous data representation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.49.1-49
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• 2001

The skin color model is a very important concept in face detection, face recognition and face tracking. Usually, this model is obtained by estimating a probability density function of skin color distribution. In many cases, it is assumed that the underlying density function follows a Gaussian distribution. In this paper, a new method for non-parametric estimation of the probability density function, by using feed-forward neural network, is used to estimate the underlying skin color model. By using this method, the resulting skin color model is better than the Gaussian estimation and substantially approaches the real distribution. Applications to face detection and face ...

• 한국멀티미디어학회논문지
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• 제10권9호
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• pp.1185-1196
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• 2007

게임산업의 경쟁력을 강화하고 부가가치를 높이기 위하여 수요자가 요구하는 높은 만족도를 갖는 게임을 개발할 수 있도록 만족도를 정량적으로 평가하여 만족도 기준을 제시할 수 있는 연구 및 근거가 필요하다. 특히 만족도 요소들의 점수화와 모집단 분포의 추정은 중요한 과제로서 이를 통하여 어떤 게임이 다른 게임에 비하여 만족도가 높은지 낮은지를 알 수 있으며 만족도를 제고시키기 위하여 보완해야 할 요소들과 기술력을 예측할 수 있다. 본 연구에서는 게임 만족도 요소들의 접수분포를 정규화 하는 방법을 제 안하고 시뮬레이션을 통한 모수적 밀도함수 추정방법을 이용하여 모집단 분포를 추정하였다.

• Journal of the Korean Statistical Society
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• 제30권3호
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• pp.453-465
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• 2001

It is often the case that one wants to estimate parameters of the distribution which follows certain parametric model, while the dta are contaminated. it is well known that the maximum likelihood estimators are not robust to contamination. Basuet al.(1998) proposed a robust method called the minimum density power divergence estimation. In this paper, we investigate data-driven selection of the tuning parameter $\alpha$ in the minimum density power divergence estimation. A criterion is proposed and its performance is studied through the simulation. The simulation includes three cases of estimation problem.

• Communications for Statistical Applications and Methods
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• 제10권2호
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• pp.607-617
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• 2003

This paper offers a practical comparison of efficiency between local likelihood approach and conventional kernel approach in density estimation. The local likelihood estimation procedure maximizes a kernel smoothed log-likelihood function with respect to a polynomial approximation of the log likelihood function. We use two types of data driven bandwidths for each method and compare the mean integrated squares for several densities. Numerical results reveal that local log-linear approach with simple plug-in bandwidth shows better performance comparing to the standard kernel approach in heavy tailed distribution. For normal mixture density cases, standard kernel estimator with the bandwidth in Sheather and Jones(1991) dominates the others in moderately large sample size.

• 한국게임학회 논문지
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• 제8권3호
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• pp.23-30
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• 2008

게임 완성도 향상 및 수출 증가 등 게임산업 경쟁력 강화를 위해서 수요자들의 게임만족도가 일정한 수준에 도달해야 되며 이를 위하여 기존 또는 향후 개발되는 게임들의 만족도가 어느 정도 되는지를 평가할 수 있는 연구가 필요하다. 본 논문에서는 게임산업의 경쟁력과 부가가치를 높이기 위한 방안으로 게임만족도 요소들의 점수분포를 추정하는 방법을 연구하였다. 그리고 온라인 RPG 게임을 대상으로 얻은 설문자료에 근거하여 SAS/INSIGHT의 모수적 밀도함수 추정방법을 이용하여 만족도 요소들의 점수분포를 각각 정규분포로 추정하였다. 제안된 방법을 활용하여 기존 또는 향후 개발되는 게임들의 만족도 수준과 기준을 예측할 수 있는 기대효과를 얻을 수 있다.

• The Korean Journal of Physiology and Pharmacology
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• 제13권5호
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• pp.367-371
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• 2009

The estimation of 90% parametric confidence intervals (CIs) of mean AUC and Cmax ratios in bioequivalence (BE) tests are based upon the assumption that formulation effects in log-transformed data are normally distributed. To compare the parametric CIs with those obtained from nonparametric methods we performed repeated estimation of bootstrap-resampled datasets. The AUC and Cmax values from 3 archived datasets were used. BE tests on 1,000 resampled data sets from each archived dataset were performed using SAS (Enterprise Guide Ver.3). Bootstrap nonparametric 90% CIs of formulation effects were then compared with the parametric 90% CIs of the original datasets. The 90% CIs of formulation effects estimated from the 3 archived datasets were slightly different from nonparametric 90% CIs obtained from BE tests on resampled datasets. Histograms and density curves of formulation effects obtained from resampled datasets were similar to those of normal distribution. However, in 2 of 3 resampled log (AUC) datasets, the estimates of formulation effects did not follow the Gaussian distribution. Bias-corrected and accelerated (BCa) CIs, one of the nonparametric CIs of formulation effects, shifted outside the parametric 90% CIs of the archived datasets in these 2 non-normally distributed resampled log (AUC) datasets. Currently, the 80~125% rule based upon the parametric 90% CIs is widely accepted under the assumption of normally distributed formulation effects in log-transformed data. However, nonparametric CIs may be a better choice when data do not follow this assumption.

• 문화기술의 융합
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• 제8권1호
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• pp.531-536
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• 2022

본 논문은 꼬리가 두꺼운 분포의 꼬리부분에 대한 분포를 추정할 경우 모수적 방법과 비모수적 방법의 성능에 대해 비교하였다. 모수적 방법으로는 일반화 극단값 분포와 일반화 파레토 분포를 이용하였고, 비모수적 방법은 커널형 확률밀도함수 추정방법을 적용하였다. 두 접근법의 비교를 위해 2014년부터 2018년까지 서울시 관측소별 일일 미세먼지 공공데이터를 이용하여 블록 최댓값 모형과 분계점 초과치 모형을 적용하여 함수 추정한 결과를 함께 보이고 2년, 5년, 10년의 재현수준을 통해 고농도의 미세먼지가 일어날 지역을 예측하였다.

• Communications for Statistical Applications and Methods
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• 제8권2호
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• pp.483-497
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• 2001

When one fits a parametric density function to a data set, it is usually advisable to test the goodness of the postulated model. In this paper we study the nonparametric tests for testing the null hypothesis against general alternatives, when the null hypothesis specifies the density function up to unknown parameters. We modify the test statistic which was proposed by the first author and his colleagues. Asymptotic distribution of the modified statistic is derived and its performance is compared with some other tests through simulation.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1998년도 추계학술대회
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• pp.78-79
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• 1998

This paper describes a real time algorithm for blood flow estimation of LDF(laser Doppler flowmeter). Many algorithms for blood flow estimation are using power spectral density of Doppler signal by blood flow. In these research, the fast Fourier transformation is used to estimate power spectral density. This is a block processing procedure rather than real time processing. The algorithm in this paper used parametric spectral estimation. This has real time capability by estimation of AR(autoregressive) parameters sample by sample, and has smoothing power spectrum. Also, the frequency resolution is not limited by number of samples used to estimate AR parameter. Another advantage of this algorithm is that AR model enhance SNR.