• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1734-1741
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• 2023

This work presents the synthesis and preparation of a new glass system described by the equation of (70-x) B₂O₃-5TeO₂ -20SrCO₃-5ZnO -xBi₂O₃, x = 0, 1, 5, 10, and 15 mol. %, using the melt quenching technique at a melting temperature of 1100 ℃. The photon-shielding characteristics mainly the linear attenuation coefficient (LAC) of the prepared glass samples were evaluated using Monte Carlo (MC) simulation N-particle transport code (MCNP-5) at gamma-ray energy extended from 59 keV to 1408 keV emitted by the radioisotopes Am-241, Ba-133, Cs-137, Co-60, Na-22, and Eu-152. Furthermore, we observed that the Bi₂O₃ content of the glasses had a significantly stronger impact on the LAC at 59 and 356 keV. The study of the lead equivalent thickness shows that the performance of fabricated glass sample with 15 mol.% of Bi₂O₃ is four times less than the performance of pure lead at low gamma photon energy while it is enhanced and became two times lower the perforce of pure lead at high energy. Therefore, the fabricated glasses special sample with 15 mol.% of Bi₂O₃ has good shielding properties in low, intermediate, and high energy intervals.

• The Korean Journal of Applied Statistics
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• v.19 no.3
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• pp.555-564
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• 2006

Friedman rank-sum multiple comparison procedure is often applied to nonparametric multiple comparison method under randomized block design. Since this method does not use between-block information, we propose, in this paper, nonparametric multiple comparison procedures employing aligned method suggested by Hedges and Lehmann(1962) under randomized block design. The proposed procedure and Friedman procedure are compared by Monte Carlo simulation study.

• Annual Conference on Human and Language Technology
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• 2018.10a
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• pp.580-583
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• 2018

본 논문에서는 SeqGAN 모델을 사용하여 한국어 시를 자동 생성해 보았다. SeqGAN 모델은 문장 생성을 위해 재귀 신경망과 강화 학습 알고리즘의 하나인 정책 그라디언트(Policy Gradient)와 몬테카를로 검색(Monte Carlo Search, MC) 기법을 생성기에 적용하였다. 시 문장을 자동 생성하기 위한 학습 데이터로는 사랑을 주제로 작성된 시를 사용하였다. SeqGAN 모델을 사용하여 자동 생성된 시는 동일한 구절이 여러번 반복되는 문제를 보였지만 한국어 텍스트 생성에 있어 SeqGAN 모델이 적용 가능함을 확인하였다.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.421-424
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• 1998

In this paper are presented a newly proposed 3D monte carlo (MC) damage model for the dynamic simulation in order to more accurately and consistently predict the implant-induced point defect distributions of the various ions in crystalline silicon. This model was applied to phosphorus implants for the ULSI CMOS technology developement. In additon, a newly applied 3D-trajectory split method has been implemented into our model to reduce the statistical fluctuations of the implanted impurity and the defect profiles in the relatively large implanted area as compared to 1D or 2D simulations. Also, an empirical electronic energy loss model is proposed for phosphorus and silicon implants. The 3D formations of the amorphous region and the ultra-shallow junction around the implanted region could be predicted by using our model, TRICSI(Transport ions into crystal-silicon).

• Journal of the Korean Statistical Society
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• v.36 no.1
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• pp.129-148
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• 2007

Frailty estimates from the proportional hazards frailty model often lead us to conjecture the heterogeneity in frailty such that the variance of the frailty varies over different covariate groups (e.g. male group versus female group). For such systematic heterogeneity in frailty, we consider a regression model for the variance components in the proportional hazards frailty model, denoted by the MLFM. However, in many cases, the observed data do not show any statistically significant preference between the homogeneous frailty model and the heterogeneous frailty model. In this paper, we propose a Bayesian model averaging procedure with the reversible jump Markov chain Monte Carlo which selects the appropriate model automatically. The resulting regression coefficient estimate ignores the model uncertainty from the frailty distribution in view of Bayesian model averaging (Hoeting et al., 1999). Finally, the proposed model and the estimation procedure are illustrated through the analysis of the kidney infection data in McGilchrist and Aisbett (1991) and a simulation study is implemented.

• Communications for Statistical Applications and Methods
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• v.21 no.2
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• pp.147-160
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• 2014

In this paper, we introduce the exponentiated Weibull-geometric (EWG) distribution which generalizes two-parameter exponentiated Weibull (EW) distribution introduced by Mudholkar et al. (1995). This proposed distribution is obtained by compounding the exponentiated Weibull with geometric distribution. We derive its cumulative distribution function (CDF), hazard function and the density of the order statistics and calculate expressions for its moments and the moments of the order statistics. The hazard function of the EWG distribution can be decreasing, increasing or bathtub-shaped among others. Also, we give expressions for the Renyi and Shannon entropies. The maximum likelihood estimation is obtained by using EM-algorithm (Dempster et al., 1977; McLachlan and Krishnan, 1997). We can obtain the Bayesian estimation by using Gibbs sampler with Metropolis-Hastings algorithm. Also, we give application with real data set to show the flexibility of the EWG distribution. Finally, summary and discussion are mentioned.

• Solar Energy
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• v.20 no.3
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• pp.61-73
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• 2000

Heat losses from receivers for a dish-type solar energy collecting system are numerically investigated. The analytical method for predicting conductive heat loss from a cavity receiver is used. The Stine and McDonald Model is used to estimate convective heat loss. Two kinds of techniques for the radiation analysis are used. The Net Radiation Method that is based on the radiation heat balance on the surface is used to calculate the radiation heat transfer rate from the inside surface of the cavity receiver to the environment. The Monte-Carlo Method that is the statistical approach is adopted to predict the radiation heat transfer rate from the reflector to the receiver. Based on the heat loss analysis, the performance of two different receivers for multifaceted parabolic solar collectors with several flat facets can be estimated, and the optimal facet size is obtained.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.3
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• pp.374-380
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• 2015

As semiconductor devices are being scaled down, random variation becomes a critical issue, especially in the case of static random access memory (SRAM). Thus, there is an urgent need for statistical methodologies to analyze the impact of random variations on the SRAM. In this paper, we propose a novel sampling method based on the concept of a confidence ellipse. Results show that the proposed method estimates the SRAM margin metrics in high-sigma regimes more efficiently than the standard Monte Carlo (MC) method.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.33-38
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• 2004

Molecular modeling of gas permeation through zeolite membranes with/without intercrystalline region was carried out. Molecular dynamics (MD) and Monte Carlo (MC) simulations were performed to estimate the diffusion coefficient and adsorption parameters respectively, and our proposed combined method of molecular simulation techniques with a permeation theory (CMP) was used to estimate gas permeability. The calculated permeability of gases (Ar, He, Ne, $N_2$, $0_2$, $CH_4$) at 301 K for the single crystal membrane model was about one order of magnitude larger than the experiential values, although the dependence on the molecular weight of the permeating species agreed with experiments. On the other hand, the estimated permeability using the diffusivity and adsorption parameters of the intercrystalline region model was in good agreement with the experiments. The consistency between experiments and the estimated values means the importance of considering the intercrystalline region and the validity of CMP method to predict the performance of zeolite membranes.

• 한국벤처창업학회:학술대회논문집
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• 2019.11a
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• pp.135-141
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• 2019

최근 대표적 글로벌 유통기업인 미국의 아마존과 중국의 알리바바가 전 세계적으로 가장 큰 시장점유가 있으며 두 기업의 국내진입 시 국내 유통산업에 큰 영향을 미칠 것으로 예상한다. 두 기업은 온라인 기업이 오프라인 기업을 흡수 합병함으로써 새로운 가치를 창출해내는 O2O (Online to Offline) 추세가 국제적으로 진행되고 있다. 아마존과 알리바바와 같은 글로벌 유통업체들은 일본, 인도와 같은 타 국가로의 세계 진출을 적극적으로 하는 추세이다. 본 연구에서는 아마존, 알리바바와 같은 글로벌 유통업체가 세계 진출의 일환으로 국내 유통시장 진입 시, 노출된 글로벌 경쟁 속에서 국내 유통기업들의 사업전망을 예측해보고, 해당 예측에 기반하여 기업 차원의 전략적 대응방안 및 정부 차원의 정책 지원방안을 마련하는 데 그 목적이 있다. 시장 현황분석을 기반으로 하여, 미래 시장예측 방법으로써 무작위로 추출된 난수(Random Number)를 이용하여 원하는 방정식의 값을 확률적으로 구하기 위한 알고리즘(Algorithm) 및 시뮬레이션(Simulation)의 방법인 몬테카를로(Monte Carlo, MC) 방법론을 사용하여 국내 유통시장의 변화를 예측하여 본 연구를 진행하였다.