• Journal of the Korean Data and Information Science Society
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• 제14권2호
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• pp.247-255
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• 2003

Hypothesis testing for the equality of two distributions were considered. Nonparametric kernel density estimates were used for testing equality of distributions. Cross-validatory choice of bandwidth was used in the kernel density estimation. Sampling distribution of considered test statistic were developed by resampling method, called the bootstrap. Small sample Monte Carlo simulation were conducted. Empirical power of considered tests were compared for variety distributions.

• Journal of the Korean Statistical Society
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• 제28권4호
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• pp.443-455
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• 1999

A simulation-based approach to estimating the probability of an arbitrary region under a multivariate normal distribution is developed. In specific, the probability is expressed as the ratio of the unrestricted and the restricted multivariate normal density functions, where the restriction is given by the region whose probability is of interest. The density function of the restricted distribution is then estimated by using a sample generated from the Gibbs sampling algorithm.

• 한국응용곤충학회지
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• 제48권1호
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• pp.45-51
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• 2009

본 연구의 목적은 쌀 저장창고에서 추출기를 이용하여 해충의 밀도를 추정하기 위한 축차추출법을 개발하는데 있다. 쌀 저장창고에서는 쌀을 주로 1톤의 톤백에 저장하는데, 현미로 저장되는 경우 어리쌀바구미 성충과 화랑곡나방 유충은 모두 부의 이항분포를 보였다. 축차추출법은 표본 추출 단위당 방제 시작 밀도를 0.1(현미 1 kg당 5마리), 비처리 밀도를 0.05(현미 1 kg당 2.5마리) 그리고 I($\alpha$), II형($\beta$) 오류를 0.3으로 설정하여 순차적 확률비 검정(sequential probability ratio test (SPRT))을 통해 개발하였다. 이러한 결과들은, SPRT법을 사용함으로써, 관리자들이 단지 20회의 표본 추출로도 잘못된 판단의 위험을 최소화하면서 의사결정을 할 수 있다는 것을 보여준다.

• 한국통신학회논문지
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• 제38C권10호
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• pp.852-857
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• 2013

본 논문은 오류 마루 영역에서 우수한 성능을 가지는 비이진 LDPC (low-density parity-check) 부호의 설계 방법을 제안하고 성능을 검증한다. 제안된 설계 방법은 비이진 LDPC 부호의 이진 최소 거리(binary minimum distance)를 최대화하도록 패리티 검사 행렬의 비이진 원소 값들을 결정한다. BPSK (binary phase-shift keying) 변조 방식 하에서 제안된 방법으로 설계된 비이진 LDPC 부호가 오류 마루(error floor) 영역에서 우수한 성능을 가지는 것을 Monte Carlo 시뮬레이션과 중요도 표본 추출(importance sampling) 기법을 사용하여 검증한다.

• 한국화재소방학회논문지
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• 제16권4호
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• pp.28-32
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• 2002

성능위주의 화재감지설비 설계시 공조설비 또는 실내 온도조절장치에 의한 실내기류 순환으로 연기기류가 정상해석에 의한 연기분포, 연기농도가 형성되지 못하여 화재감지지연이 예상되는 것을 실험 및 분석을 통하여 성능위주의 예방설비 구현을 위한 연구를 수행하였다. 실험연구는 공조설비가 가동하고 있는 통신기계실의 화재시 화재감지기의 작동을 예측하고자 천장부의 연기농도분포를 측정·분석하는 실험을 수행하였으며, 그 결과 기류순환에 의해 기존 Passive Type의 화재감지장치는 감지불가 또는 감지지연이 예상되었으며, 조기화재감지를 위하여 방호공간의 공기를 강제로 흡입·분석하여 화재를 감지하는 Active Type의 Air Sampling Smoke Detection system의 적용이 필요한 것으로 나타났다.

• Communications for Statistical Applications and Methods
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• 제26권2호
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• pp.217-238
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• 2019

With the advent of so-called "default" Bayesian hypothesis tests, scientists in applied fields have gained access to a powerful and principled method for testing hypotheses. However, such default tests usually come with a compromise, requiring the analyst to accept a one-size-fits-all approach to hypothesis testing. Further, such tests may not have the flexibility to test problems the scientist really cares about. In this tutorial, I demonstrate a flexible approach to generalizing one specific default test (the JZS t-test) (Rouder et al., Psychonomic Bulletin & Review, 16, 225-237, 2009) that is becoming increasingly popular in the social and behavioral sciences. The approach uses two results, the Savage-Dickey density ratio (Dickey and Lientz, 1980) and the technique of encompassing priors (Klugkist et al., Statistica Neerlandica, 59, 57-69, 2005) in combination with MCMC sampling via an easy-to-use probabilistic modeling package for R called Greta. Through a comprehensive mathematical description of the techniques as well as illustrative examples, the reader is presented with a general, flexible workflow that can be extended to solve problems relevant to his or her own work.

• Journal of Ecology and Environment
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• 제47권2호
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• pp.35-41
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• 2023

Background: Several species of amphibians in agricultural areas are often infected with ranaviruses; however, the biological or ecological factors that cause this infection are not well understood. In this study, we investigated whether local tadpole density, Gosner developmental stage, and weather conditions affected ranavirus infection in Dryophytes japonicus tadpoles in rice paddies over three months. Results: During the study, eight samplings were undertaken between June 6 and August 21, 2022. No die-off of tadpoles occurred, but 20 of 110 tadpoles (18.8%) were found to be infected with ranavirus. The tadpole density at the sampling site and Gosner stage of the sampled tadpoles were not related to the daily ranavirus infection rate. The mean daily highest temperature during the two weeks prior to the sampling date and the mean daily lowest and highest temperatures during the week prior to the sampling date were negatively related to the daily infection rate. Conclusions: Our results suggest that low and extreme temperatures caused by flooding and draining of paddy fields or climate change in summer could be a significant risk factor for ranavirus infection in summer-breeding frogs in agricultural areas.

• Structural Engineering and Mechanics
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• 제5권2호
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• pp.115-126
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• 1997

Importance sampling methods have been developed with the aim of reducing the computational costs inherent in Monte Carlo methods. This study proposes a new algorithm called the adaptive kernel method which combines and modifies some of the concepts from adaptive sampling and the simple kernel method to evaluate the structural reliability of time variant problems. The essence of the resulting algorithm is to select an appropriate starting point from which the importance sampling density can be generated efficiently. Numerical results show that the method is unbiased and substantially increases the efficiency over other methods.

• 수산해양기술연구
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• 제49권4호
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• pp.483-491
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• 2013

The sound-speed and density contrasts are important factors in estimating the target strength (TS) of moon jellyfish (Aurelia aurita). In this study, the sound-speed and density contrasts were measured using time-of-flight and neutral buoyancy methods, respectively. The sound-speed contrast of A. aurita was from 0.9966 to 1.0031 (mean${\pm}$SD, $0.9999{\pm}0.0017$) and no distinct differences in temperature or pulsation activity and weak were found. The density contrast was from 0.9994 to 1.0004 (mean${\pm}$SD, $1.0000{\pm}0.0002$). The density of A. aurita was substantially different but the density contrast of A. aurita was shown to be similar to that in the sampling location. The results can be used to estimate of TS of A. aurita by acoustic model.

• 대한전자공학회논문지
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• 제17권1호
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• pp.14-22
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• 1980

이차원 영상 재구성을 위해서는 Fouler convolution 알고리즘이 주로 사용되고 있다. 이때 사용되는 필터의 설계에는 몇가지 선택의 여지가 있다. 이 논문은 지금까지 제안된 영상 재구성 필터들을 sampling rate와 aliasing과 잡음의 견지에서 이론적으로 비교, 검토하고 이를 토대로 새로운 필터의 설계방법을 제안하였다. 또한 컴퓨터 simulation을 통해 기존의 재구성 필터와 제안된 필터의 이론적인 분석 결과를 확인, 검토하였다.