층상 반무한체에서의 확률론적 완전파형역산을 위한 Markov chain Monte Carlo (MCMC) 모사 기법을 정식화한다. Thin-layer method를 사용하여 조화 수직 하중이 작용하는 층상 반무한체의 지표면에서 추정된 동적 응답과 관측 데이터와의 차이 및 모델 변수 의 사전 정보와의 차이를 최소화하도록 목적함수와 모델 변수의 사후 확률밀도함수를 정의한다. 목적함수의 기울기에 기반하여 MCMC 표본을 제안하기 위한 분포함수와 이를 수락 또는 거절할지 결정하는 수락함수를 결정한다. 기본 진동모드 뿐만이 아니라 고 차 진동모드가 우세한 경우를 포함하여 다양한 층상 반무한체의 전단파 속도 추정에 제안된 MCMC 모사 기법을 적용하고 그 정확성 을 검증한다. 제안된 확률론적 완전파형역산을 위한 MCMC 모사 기법은 층상 반무한체의 전단파 속도와 같은 재료 특성의 확률적 특 성을 추정하는 데 적합함을 확인할 수 있다.

Considering the Fukushima nuclear accident and the marine discharge plan of contaminated (or treated) water, it is necessary a seafood monitoring system for radioactive material screening. Currently, radioactivity tests in seafood are conducting in Korea. Although current method using a HPGe detector can provide very low uncertainty in determining radioactivity, there is a limitation in that rapid inspection cannot be performed because of a time-consuming pretreatment process as well as long measurement time (typically 10,000 s). To overcome this limitation, we are developing an insitu inspection device, a kind of screening system, which can monitor the radioactivity in seafood in a near real-time basis. In this study, the actual seafood with a check source was measured to verify the reliability of the Monte Carlo simulation model. The detector used in the experiment was a 5-cm-thick polyvinyl toluene (PVT) plastic scintillator with a 0.5-cm-thick lead shield for background reduction. A Cs-137 check source was placed within seafood. The seafood used in the experiment was fishcake, raw oyster, and dried laver, which is the representative seafood of fish, shellfish, and seaweed. These three seafood products of the same size and shape as the manufacturing process were used to predict the performance realistically. We compared the energy spectrum of the Cs-137 check source obtained from measurements and simulations. The region of interest (ROI) around the Compton edge was set to reduce the influence of the background and electronic noise. The results showed that the measured and simulated spectrum were in good agreement.

The detector response was simulated to design a fork detection system for verifying the characteristics of spent fuel. The fork detection system currently used consists of two fission chamber and an ion chamber, and it is nuclear safeguard equipment that measures the gross neutrons and gross gamma rays emitted from the spent fuel assembly to identify the characteristics of the spent fuel and verify the authenticity of the operation history. In order to improve the current fork detection system, we are developing a system that applies CZT, a room temperature semiconductor detector, and a stilbene detector, which is an organic scintillator. Depletion calculations were performed using the ORIGEN code to determine the radiological characteristics emitted from spent nuclear fuel assembly. The flux of radiation emitted from the spent nuclear fuel assembly was calculated by changing the conditions such as initial enrichment, burnup, and cooling time, which are major variables of spent fuel assembly. The calculated result is used as the source term of the particle transport code. Considering the general operating conditions of the pressurized light water reactor, the conditions were changed in the range of 3-5% for initial enrichment and 30-72 GWD/MTU for burnup, and the cooling time was given within 10 years. MCNP 6.2, a Monte Carlo simulation code, was used to simulate the detector response to radiation emitted from spent nuclear fuel assembly. According to the shape, size, and position of the CZT detector, the gamma counts incident on the detector were calculated and derived the initial design of our fork detection system.

Sea trial tests are necessary to verify speed-power performance, and are an import contract between ship owners and shipyards. The International Organization for Standardization (ISO) published ISO 15016:2015, which specifies the correlation method between model and full-scale ships. The results of sea trials have been questioned because of the uncertainty of speed and power measurements, especially when sea conditions differ from ideal calm water conditions. In this paper, such uncertainties were investigated by utilizing the standard speed-power trial analysis procedure defined in ISO 15016:2015 through Monte Carlo simulations. It was found that the expanded uncertainty of the delivered power (PDid) at 95 % confidence interval (k = 2) was ±1.5 % under 75 % MCR conditions.

Dynamic modulus of Asphalt Concrete (|E*|) is one of the most important input parameters is used to design pavement structure according to mechanical-empirical Pavement design of the United State of America. Because of its importance, there has been a lot of research on predictive models of (|E*|) as well as sensitive analysis of input parameters influences dynamic modulus in order to find out which one is the most influence on (|E*|), basing on that, the most reasonable quality control and quality assurance can be applied to ensure quality of work is under control. This paper presents sensitive analysis of input parameters influence (|E*|) of dense asphalt concrete in Viet Nam according to some predictive models of dynamic modulus of the United State of America by applying Monte Carlo simulation method.

콘크리트 혼화제의 무수축 그라우트에서 산란체와 흡수체의 영향은 빛산란에 의해 파장에 대 한 산란세기로 설명된다. New Austria Tunnel Method의 수지에 대한 산란의 분자특성들은 연구하기 위해 Monte Carlo Simulation하였다. 이는 산란매질에서 광학적 파라미터들(μs, μa, μt)에 의해 조사 되어 그들의 영향을 알 수 있었다. 산란매질에서 광자에 대한 빛 분포에 의한 결과는 광원에서 검출기 까지 거리가 가까우면 무수축혼화제의 산란이 증가하여 산란세기가 크게 나타나는데 혼화제가 첨가함에 따라 무수축 성질이 크게 나타났다. 이는 강구조물의 내구성을 위한 코팅과 부식에서 좋은 모델을 디자 인하는데 도움이 될 것이다.

본 연구에서는 강풍 위험 모델과 강풍 취약도 모델을 개발하여 옥외 광고물의 강풍 위험도를 정량적으로 평가하였다. 강풍 위험 모델과 강풍 취약도 모델 모두 확률론적 접근법인 몬테카를로 모사 모형을 적용하여 개발되었으며, 강풍 위험도 모델은 평가된 강풍 위험과 강풍 취약도의 수학적 계산을 통해서 평가되었다. 강풍 위험은 국내 내륙과 해안지역의 대도시인 서울과 부산 지역에 대하여 평가되었으며, 강풍 취약도 모델은 현장 조사와 문헌 조사를 통하여 파악된 10종의 벽면 이용형, 8종의 돌출형 옥외 광고물을 대상으로 개발되었다. 강풍 위험도에 영향을 미치는 요인을 파악하기 위하여 지표조도구분, 옥외 광고물의 형태, 설치 지역, 설치 높이 등에 따른 강풍 위험도를 정량적으로 평가하였다. 본 연구에서 제안한 강풍 위험도 평가 방법은 강풍으로 인한 옥외 광고물의 손실 추정 및 피해 저감 대책 수립을 위하여 활용될 수 있을 것으로 판단된다.

Structural dynamic system involves random variables conditions such as material property, geometric parameters and applied loads. This uncertainties result from the structural parameter are carefully considered the dynamic structural response in displacement, stress, and natural frequencies. The random vibrational system must be designed to withstand a certain amount of the fluctuation with respect to the uncertainties. Harmonic response of a spring-mass system is mathematically modelled with the probabilistic finite element method using the Monte Carlo simulation. The aim of this paper is to find the optimal lowest frequency for the spring-mass system with random input variables and response parameters to the displacements. The probabilistic design is carried out using ANSYS probabilistic design module in a commercial application software and then the optimal design is sequentially solved. An efficient and practical optimal design evaluation method is proposed for the design of the harmonic system. The numerical results are obtained where the next highest frequency of the system and displacements treated as constraints.

국내 서해대교, 인천대교와 같은 장대교량은 대부분 빈번하게 태풍에 의해 영향을 받는 해안에 위치하였으며, 교량의 길이가 긴 만큼 풍하중에 의한 영향이 다른 하중에 비해 상대적으로 크기 때문에 내풍 안정성을 확보하기 위해 정확한 설계풍속을 산정하는 것이 매우 중요하다. 본 연구에서는 태풍의 기후학적 특성 인자로 중심기압깊이, 태풍이동속도, 태풍이동방향, 최단접근거리를 결정하였으며, 태풍의 기후학적 특성들의 확률 분포를 추정하고, 바람장 모형과 중심기압상승 모형을 적용하여 몬테카를로 시뮬레이션을 실시하였다. 분석결과, 대체적으로 제주도와 남해안 지역의 재현기간 풍속이 크게 나오며 고위도로 갈수록 작아지는 특징을 나타냈다. 이와 같은 특징이 나타난 가장 큰 원인은 고위도 분석지점 표본 태풍의 중심기압이 저위도 분석지점 표본 태풍의 중심기압보다 높기 때문으로 판단되며, 또한 우리나라에 해상에서 육지로 이동하면서 쇠퇴기를 겪어 점차 약해지기 때문인 것으로 분석되었다. 또한, 시뮬레이션 결과를 도로교 설계기준 100년 재현기간 풍속(10분 평균, 지상 10m, 지표조도 II)과 비교한 결과, 태풍시뮬레이션의 결과가 낮게 나타났으며, 이러한 점을 볼 때 도로교 설계기준의 기본 풍속이 높게 산정되어 있다고 판단되며, 기상자료 분석과 같은 추가적인 연구를 통해 기본풍속 조정에 대한 연구가 수행 되어야 할 것으로 사료된다.

In this paper, the numerical results concerning different orbits of a 3D axisymmetric non-rotating galactic potential are presented. We use Paczynski's gravitational potential with different birth velocity distributions for the isolated old Neutron Star (NS) population. We note some smooth non-constant segments corresponding to regular orbits as well as the characterization of their chaoticity. This is strongly related to the effect of different kick velocities due to supernovae mass-loss and natal kicks to the newly- formed NS. We further confirm that the dynamical motion of the isolated old NSs in the gravitational field becomes obvious, with some significant diffraction in the symmetry of their orbital characteristics.

Structural system involves random conditions such as material property, geometric parameters and applied loads. This is caused by either measurement inaccuracy or system complexity and must be designed to withstand the uncertainties, Random structures may be modelled by using the finite element method using Monte Carlo simulation. It can be applied easily to any structural system with random parameters. The aim of this paper is to find the shape optimal design for the cantilever beam with random input variables to the height and response parameters to the displacement and stresses. The probabilistic design is carried out using ANSYS probabilistic design module in a commercial application software and then the optimal design is sequentially solved. An efficient and practical shape optimal design evaluation method is proposed for the design of the cantilever beam shape. The numerical results are obtained where total volume of the beam, stresses and displacements in the beam treated as constraints