• Journal of the Korean Data and Information Science Society
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• 제6권1호
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• pp.31-37
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• 1995

We consider density estimates of the usual type generated by a kernel function. By using the limit theorems for the maximum of normalized deviation of the estimate from its expected value, we propose to use data dependent bandwidth in the tests of goodness of fit based on these statistics. Also a small sample Monte Carlo simulation is conducted and proposed method is compared with Kolmogorov-Smirnov test.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.140-141
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• 2006

Most PM components are exposed to cyclic loading over long periods of time, yet, the fatigue performance is often at best characterized by a fully reversed bending strength. The effects of density, deviating loading modes, external notches or mean stresses must usually be estimated. The amount of available data is nowadays sufficient to come to fact-based estimates.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2005년도 ICCAS
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• pp.408-413
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• 2005

A new methodology for discrete non-Gaussian probability density estimation is investigated in this paper based on a dynamic Bayesian network (DBN) and kernel functions. The estimator consists of a DBN in which the transition distribution is represented with kernel functions. The estimator parameters are determined through a recursive learning algorithm according to the maximum likelihood (ML) scheme. A discrete-type Poisson distribution is generated in a simulation experiment to evaluate the proposed method. In addition, an unknown probability density generated by nonlinear transformation of a Poisson random variable is simulated. Computer simulations numerically demonstrate that the method successfully estimates the unknown probability distribution function (PDF).

• Communications for Statistical Applications and Methods
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• 제2권2호
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• pp.231-242
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• 1995

In this paper we consider kernel type estimator of the spectral density at a point in the analysis of stationary time series data. The kernel entails choice of smoothing parameter called bandwidth. A data-based bandwidth choice is proposed, and it is obtained by solving an equation similar to Sheather(1986) which relates to the probability density estimation. A Monte Carlo study is done. It reveals that the spectral density estimates using the data-based bandwidths show comparatively good performance.

• 대한전기학회논문지
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• 제45권2호
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• pp.325-328
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• 1996

In this paper, we proposed an estimation method of a posterior probability and PDF(Probability density function) using a feed forward neural network and code books of VQ(vector quantization). In this study, We estimates a posterior probability and probability density function, which compose a new parameter with well-known Mel cepstrum and verificate the performance for the five vowels taking from syllables by NN(neural network) and PNN(probabilistic neural network). In case of new parameter, showed the best result by probabilistic neural network and recognition rates are average 83.02%.

• 한국전자파학회논문지
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• 제20권1호
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• pp.100-106
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• 2009

본 논문에서는 직교 위상 수신기에서 발생하는 동상 성분 채널과 직교 성분 채널간의 이득과 위상 불평형의 추정문제를 다룬다. 즉, 자동 보정 기능을 가지는 직교 위상 수신기에서의 백색 Gaussian 잡음을 고려한 통계적인 특성 분석을 통하여 제안된 알고리즘에 의한 추정값이 점근적으로 비편향 최소 분산 추정(asymptotically minimum-variance unbiased estimate) 특성을 가짐을 보여준다. 이를 위하여 먼저 자동 보정 알고리즘에서 사용하는 샘플링 값들에 대한 통계적인 특성을 구하고, 이 샘플 값들의 함수의 형태로 구해지는 이득과 위상 불평형 추정값들의 통계적인 특성을 분석하기 위해 추정값들의 확률분포함수를 구한다. 이를 기반으로 평균 함수 및 분산 함수를 계산하여 추정값들이 비편향 최소 분산 추정 특성을 나타냄을 확인한다.

• 천문학회지
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• 제22권1호
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• pp.63-79
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• 1989

Current estimates, based on the same star-count analysis, of the distance to the globule Bamard 361 range from 300 pc to 650 pc. All the problems associated with the estimates have been fully rectified in this study, and a modification has been made to the classical Wolf diagram to improve the accuracy in the distance determination. A reference field was carefully selected close to the globule but well outside the globule boundary, and star counts for this field were performed on the blue POSS plate in order to set up the reference magnitude sequence appropriate to the general area of B 361. From the reference sequence, the stellar density function has been derived specifically for the direction toward the globule. Correction was made for the general interstellar extinction, and the luminosity function with the Wielen's dip was adopted. The resulting density function clearly reveals the existence of the local Cygnus-Orion arm in the direction of B 361 at about 700 pc away from the Sun. Analysis of the star-count data for the program field locates the globule at distance $600{\pm}50$ pc ; thus, the globule is an object located in the Cygnus-Orion arm, residing somewhat toward its leading edge.

• 한국인터넷방송통신학회논문지
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• 제8권4호
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• pp.75-88
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• 2008

본 논문은 입력 이미지 블록의 클래스 조건부 확률 밀도 함수의 커널 추정에 기반한 공간 영역에서의 다중초점 이미지 융합 기법을 제안한다. 이미지 융합 문제를 시험 패턴으로부터 추정된 유사 밀도 함수에 의해 사후 클래스 확률, P($w_{i}{\mid}B_{ikl}$),을 계산하는 분류 임무로 접근하였다. C개의 입력 이미지 $I_{i}$에 대하여 제안한 방법은 i 클래스 $w_{i}$를 정의하고 베이즈 결정 원리에 기초하여 판별 함수를 최대화하는 PxQ 블록 $B_{ikl}$의 집합에 의해 표현되는 결정 지도로 부터 융합 이미지 Z(k,l)를 형성한다. 출력 화질의 척도로서 RMSE 와 상호 정보량인 MI를 사용하여 제안한 기법의 성능이 평가되었다. 커널 함수의 폭 ${\sigma}$ 도 변화시키고, 다른 종류의 커널과 블록 크기를 변화시켜 가며 성능평가를 수행하였다. 제안한 가법은 C=2 와 C=3에 대하여 시험하였고 시험 결과는 좋은 성능을 보였다.

• 한국컴퓨터그래픽스학회논문지
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• 제30권3호
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• pp.141-147
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• 2024

점진적 광자 매핑 방식은 복잡한 전역 조명 효과를 효율적으로 렌더링할 수 있다. 그러나 샘플이 유한한 경우, 반경 축소비율 변수에 의해 분산과 편향 값이 크게 영향 받는다. 유한한 샘플을 사용한 렌더링 결과의 픽셀 오류 및 기울기를 추정하여 추정된 기울기를 기반으로 반경 축소비율을 결정하는 최적의 매개변수를 학습할 수 있다면, 렌더링 된 이미지의 오류를 줄일 수 있을 것이다. 본 논문에서는 점진적 광자 매핑 방식을 통한 렌더링과 매개변수 학습이 동시에 될 수 있도록 기울기를 추정하고 추정된 기울기를 유한 차분법을 통해 계산된 기울기와 비교하여 검증한다. 본 논문에서 추정된 기울기는 향후 점진적 광자 매핑 방식의 렌더링과 매개변수 추정을 동시에 수행하는 온라인 학습 알고리즘에 적용될 수 있을 것으로 기대된다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권13호
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• pp.5229-5232
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• 2014

Background: While many studies have concluded that local traffic density is positively associated with childhood leukemia, the results are inconsistent. We therefore performed a meta-analysis to assess the relationship between traffic density and the risk of childhood leukemia. Methods: A systematic literature review was carried out using PubMed, EMBASE, and the Cochrane Library from January 1979 to December 2013. We selected and assessed journal articles evaluating the relationship between local traffic density and the risk of leukemia in children. The analysis was carried out using STATA version 12.0. Results: A total of 11 articles, including 12 estimates of effect, were included in our meta-analysis. The summary effect size from the random-effects model, expressed as an odds ratio, was 1.03 (95% CI: 0.98-1.09, p=0.002). No significant association between traffic density and the risk of childhood leukemia was found. Similar conclusions were found on subgroup analysis. Conclusions: The results of our meta-analysis suggested no association between traffic density and the risk of childhood leukemia. This implies that living in close proximity to roads with heavy traffic may not increase the risk of childhood leukemia. However, further high-quality prospective trials are needed to support these results.