• Korean Journal of Optics and Photonics
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• v.22 no.5
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• pp.207-213
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• 2011

We propose a new method to measure the phase errors of an AWG(arrayed waveguide grating) through Monte-Carlo analysis. In the frequency domain method, we used the Monte-Carlo method to fit the theory to the experimental results. The phase and amplitude values are obtained from the fitted theory. To verify our method, we carried out a simulation. Some phase errors were included to make a virtual interferogram and we measured the actual AWG phase errors from it by our method. The results show that our method gives good results if the laser tuning range is larger than 1.7 times of the AWG FSR(free spectral range) and if the phase errors are within ${\pm}50^{\circ}$.

• Journal of Satellite, Information and Communications
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• v.9 no.4
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• pp.104-110
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• 2014

This paper considers two reconstruction schemes of structured-sparse signals, turbo inference and Markov chain Monte Carlo (MCMC) inference, in compressed sensing(CS) technique that is recently getting an important issue for an efficient video wireless transmission system using multi-copter as an unmanned aerial vehicle. Proposed reconstruction algorithms are setting importance on reduction of image data sizes, fast reconstruction speed and errorless reconstruction. As a result of experimentation with twenty kinds of images, we can find turbo reconstruction algorithm based on loopy belief propagation(BP) has more excellent performances than MCMC algorithm based on Gibbs sampling as aspects of average reconstruction computation time, normalized mean squared error(NMSE) values.

• Journal of the Korean Chemical Society
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• v.56 no.6
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• pp.768-771
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• 2012

• Proceeding of EDISON Challenge
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• 2017.03a
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• pp.64-74
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• 2017

본 연구에서는 동역학 격자기반 대정준 Monte Carlo (Kinetic Lattice Grand Canonical Monte Carlo, KLGCMC) 모의실험 방법과 Poisson-Nernst-Planck (PNP) 계산 방법을 이용하여 이온채널의 전하분포, 채널 반지름, 그리고 이온의 농도와 이온의 크기가 이온전류와 이온전도도에 미치는 영향과, 이온 간 상관관계 (correlation)가 이온전류와 이온전도도에 미치는 영향을 조사하였다. 이로부터 이온 간 상호작용에 의해 이온 이동에 제약이 가해지는 이온 간 상관관계 효과는 채널 내 이온 수가 증가할수록 커지는 것을 알 수 있었다. 또한, 평균장 이론에 기반한 PNP 이론은 이온 간 상관관계 효과를 적절하게 기술하지 못하며, 이온 간 상관관계 효과가 중요해지는 이온 채널 관련 결맞음 공명 (coherence resonance) 등 특이 현상을 연구하기 위해서는 이온 간 상관관계를 기술할 수 있는 KLGCMC 모의실험 방법이 필요함을 알 수 있었다.

• Journal of radiological science and technology
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• v.28 no.2
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• pp.117-122
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• 2005

According to the Para. 5 of Art 2 of the Korean Nuclear Safety Regulations, which was revised in 1999, internal dose assessment as well as external one should be performed by law for employees at a nuclear power plant from 2003, and their estimate errors should also be within 50%. Thus, more accurate internal dosimetry becomes important. Corresponding to such regulation revision, we are developing a more accurate thyroid-uptake internal dosimetric system and have developed a Monte Carlo simulation code, the so-called CALEFF, to calculate the detection efficiency of the dosimetric system. In this paper, we calculated detection efficiencies with various test conditions by using the CALEFF code and discussed their characteristics. We may use the detection efficiency calculated by the code in calibrating the thyroid internal dose from measured data.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.7
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• pp.51-60
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• 2002

The Monte-Carlo simulation of statistical analysis is used to investigate the final conditions of states as well as the footprint boundaries resulting from the atmospheric re-entry dispersions. The re-entry dispersions in this paper are specified by a $7\times7$ covariance matrix of latitude, longitude, altitude, bank angle, flight path angle, heading error, and range at entry velocity. The error sources that affect these at re-entry for a deboost are the uncertainties associated with atmospheric density and temperature, initial errors, wind, and estimation error of aerodynamic coefficients. Using $3{\sigma}_n$ deviations of these errors and a nominal flight trajectory, the covariance matrix of state variables can be determined by performing a trajectory error analysis. Major considerations in the application of the Monte-Carlo method are the simulation of perturbed trajectories, bank reversal, and determination of the impact points for each of these trajectories. This paper analyzes the results of uncertainties from the viewpoint of aero-coefficients and bank reversal.

• Journal of Korea Water Resources Association
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• v.36 no.2
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• pp.315-324
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• 2003

Stream flow data was analyzed for determining the lowflow which is the standard for river maintenance flow. Lowflow quantiles were estimated based on the parametric and nonparametric methods and two methods were compared by Monte Carlo simulation study. As the results of the parametric method, three probability distributions such as gamma-2, lognormal-2 and Weibull-2, are selected as appropriate models for stream flow data of 13 stations in Han River Basins. According to simulation results, relative bias (RBIAS) and relative root mean square error (RRMSE) of the lowflow quantiles are the smallest when the applied and population models are the same. The fame statistical properties from the nonparametric models are good within the interpolation range. Among 7 bandwidth selectors used in this study, the RRMSEs of the Park and Marron method (PM) are the smallest while those of the Shoaler and Jones method (SJ) are the largest.

• Communications for Statistical Applications and Methods
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• v.18 no.2
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• pp.219-227
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• 2011

In this paper, we proposed a generalized bivariate negative binomial distribution allowing heterogeneous dispersions on two dependent variables based on a trivariate reduction technique. In this model, we propose the score and LR tests for testing the equality of dispersions and compare the efficiencies of the proposed tests using a Monte Carlo study. The Monte Carlo study shows that the proposed score and LR tests prove to be an efficient test for the equality of dispersions in the view of the significance level and power. However, the score test is easier to compute than the LR test and it shows a slightly better performance than the LR test from the Monte Carlo study, we suggest the use of score tests for testing the equality of dispersions on two dependent variables. In addition, an empirical example is provided to illustrate the results.

• The Korean Journal of Applied Statistics
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• v.13 no.2
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• pp.541-562
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• 2000

The generalized linear mixed model framework is for handling count-type categorical data as well as for clustered or overdispersed non-Gaussian data, or for non-linear model data. In this study, we review its general formulation and estimation methods, based on quasi-likelihood and Monte-Carlo techniques. The current research areas and topics for further development are also mentioned.

• Journal of Astronomy and Space Sciences
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• v.15 no.2
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• pp.341-358
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• 1998

The X-ray astronomy team of the Korea Astronomy Observatory(KAO) is planning to develop a multi-cell proportional counter, adopting an anti-coincidence method to reduce its internal background. We have developed a Monte Carlo code to determine the X-ray detection efficiency of the counter. As a check of our code, we successfully reproduced the detection efficiency of Ginga/LAC. In this paper, we report the simulation results for the counter being considered in KAO.