• Communications for Statistical Applications and Methods
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• 제10권3호
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• pp.835-844
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• 2003

A difficulty in spatial data analysis is to choose a suitable theoretical variogram. Generally mean squares error(MSE) is used as a criterion of selection. However researchers encounter the case that the values of MSE are almost the same whereas the estimates of parameters are different. In this case, the selection criterion based on MSE should take into account the parameter estimates. In this paper we study on the method of selecting a variogram using spatial correlation.

• Journal of Mechanical Science and Technology
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• 제14권7호
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• pp.705-714
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• 2000

The formulation of Smoothed Particle Hydrodynamics (SPH) and a shortcoming of traditional SPH in contact simulation are presented. A contact algorithm is proposed to treat contact phenomenon between two objects. We describe the boundary of the objects with non-mass artificial particles and set vectors normal to the contact surface. Contact criterion using non-mass particles is established in this study. In order to verify the contact algorithm, an algorithm is implemented in to an in-house program; elastic wave propagation is an analysed under low velocity axial impact of two rods. The results show that the contact algorithm eliminates the undesirable phenomena at the contact surface; numerical result with the contact algorithm is compared with theoretical one.

• 한국수학교육학회지시리즈B:순수및응용수학
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• 제6권2호
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• pp.79-86
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• 1999

A Boolean function generates a binary sequence which is frequently used in a stream cipher. There are number of critical concepts which a Boolean function, as a key stream generator in a stream cipher, satisfies. These are nonlinearity, correlation immunity, balancedness, SAC (strictly avalanche criterion), PC (propagation criterion) and so on. In this paper we construct an algorithm for finding the correlation immune order of a Boolean function, and check how long to find the correlation immune order of a given Boolean function in our algorithm.

• Nuclear Engineering and Technology
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• 제53권1호
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• pp.103-110
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• 2021

In the development of a Risk Monitor probabilistic safety assessment (PSA) model from the basic PSA model of a nuclear power plant, the modeling of common-cause failure (CCF) is very important. At present, some approximate modeling methods are widely used, but there lacks criterion of modeling accuracy and error analysis. In this paper, aiming at ensuring the accuracy of risk assessment and minimizing the Risk Monitor PSA models size, we present three basic issues of CCF model resulted from the changes of a nuclear power plant configuration, put forward corresponding modeling methods, and derive accuracy criteria of CCF modeling based on minimum cut sets and risk indicators according to the requirements of risk monitoring. Finally, a nuclear power plant Risk Monitor PSA model is taken as an example to demonstrate the effectiveness of the proposed modeling method and accuracy criteria, and the application scope of the idea of this paper is also discussed.

• 인터넷정보학회논문지
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• 제13권1호
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• pp.27-36
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• 2012

본 연구는 방송 통신 서비스의 경품 및 요금 감면 행위의 위법성 판단 기준과 규제 기관의 위법 행위 적발 및 시정조치 등을 분석함으로써 규제의 실효성 여부를 알아보고 효과적 규제 방안을 제안하고자 하는 연구목적을 지니고 있다. 연구 결과, 최근 들어 이용자에게 제공되는 경품과 요금 감면액의 차이가 급속히 증가하고 있음을 알 수 있었다. 또한 공정거래위원회는 부당성 판단 기준을 비용 이하로 요금을 책정하는 경우에만 부당염매로 판단하고 있지만 방송통신위원회는 '가입자 1인당 평균 예상이익'으로 적용하고 있는데, 모든 사업자의 평균값을 기준으로 함으로써 기업이 제공하는 서비스품질의 차이나 선발기업과 후발기업 간 비용 구조 차이를 고려하지 않아 후발 기업의 마케팅 비용을 상대적으로 높게 허용해주는 결과를 낳고 있다. 이용자 차별금지를 통해 후발 기업의 가입자 증가와 영업이익의 증가를 지원하는 결과를 가져오지만, 이는 직접적인 규제 목적이 아니며 적극적으로 정보를 추구하는 정보이용자의 후생이 감소하는 결과가 나타나고 있어 부당성 판단 기준에 대한 재고찰이 필요함을 제안하였다.

• Journal of Electrical Engineering and Technology
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• 제12권1호
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• pp.363-372
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• 2017

This paper presents a novel face recognition algorithm based on the deep convolution neural network and key point detection jointed local binary pattern methodology to enhance the accuracy of face recognition. We firstly propose the modified face key feature point location detection method to enhance the traditional localization algorithm to better pre-process the original face images. We put forward the grey information and the color information with combination of a composite model of local information. Then, we optimize the multi-layer network structure deep learning algorithm using the Fisher criterion as reference to adjust the network structure more accurately. Furthermore, we modify the local binary pattern texture description operator and combine it with the neural network to overcome drawbacks that deep neural network could not learn to face image and the local characteristics. Simulation results demonstrate that the proposed algorithm obtains stronger robustness and feasibility compared with the other state-of-the-art algorithms. The proposed algorithm also provides the novel paradigm for the application of deep learning in the field of face recognition which sets the milestone for further research.

• Geomechanics and Engineering
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• 제8권3호
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• pp.461-476
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• 2015

Rankine's theory of earth pressure cannot be directly employed to c-${\phi}$ soils backfill with a sloping ground subjected to complex loadings. In this paper, an analytical solution for active earth pressures on retaining structures of cohesive backfill with an inclined surface subjected to surcharge, pore water pressure and seismic loadings, are derived on the basis of the lower-bound theorem of limit analysis combined with Rankine's earth pressure theory and the Mohr-Coulomb yield criterion. The generalized active earth pressure coefficients (dimensionless total active thrusts) are presented for use in comprehensive design charts which eliminate the need for tedious and cumbersome graphical diagram process. Charts are developed for rigid earth retaining structures under complex environmental loadings such as the surcharge, pore water pressure and seismic inertia force. An example is presented to illustrate the practical application for the proposed coefficient charts.

• Geomechanics and Engineering
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• 제7권3호
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• pp.317-333
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• 2014

The study of the mechanical behavior of rockfill materials under three-dimensional loading conditions is a current research focus area. This paper presents a microscale numerical study of rockfill deformation and strength characteristics using the Combined Finite-Discrete Element Method (FDEM). Two features unique to this study are the consideration of irregular particle shapes and particle crushability. A polydisperse assembly of irregular polyhedra was prepared to reproduce the mechanical behavior of rockfill materials subjected to axial compression at a constant mean stress for a range of intermediate principal stress ratios in the interval [0, 1]. The simulation results, including the stress-strain characteristics, relationship between principal strains, and principal deviator strains are discussed. The stress-dilatancy behavior is described using a linear dilatancy equation with its material constants varying with the intermediate principal stress ratio. The failure surface in the principal stress space and its traces in the deviatoric and meridian plane are also presented. The modified Lade-Duncan criterion most closely describes the stress points at failure.

• 한국광학회지
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• 제12권2호
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• pp.71-76
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• 2001

자연의 법칙이 보장해 주는 완벽한 보안이 가능한 양자암호화 통신을 위해서는 아주 약한 빛을 사용해 한 펄스에서 두 개 이상의 광자가 발견될 확률을 아주 작게 해야한다. 그러나 잡음과 검출기의 양자효율 등을 고려하면 현실적으로는 실험적 상황에서 발생되는 신호왜곡과 도청에 의한 신호왜곡을 구별해 낼수 있는 조건을 찾아내야 한다. 검출기에 걸어주는 전압의 크기와 신호검출시의 문턱전압을 변화시켜가며 여러 세기의 빛에 대한 양자암호화 키 전송가능성을 실험적으로 확인하였다. 암호화 키전송 방식은 잘 알려진 두 가지 선형편광과 두가지 원형편광 상태를 이용한 4-state 암호화 키 전송방식을 사용하였다.

• 한국항공운항학회지
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• 제12권2호
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• pp.29-42
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• 2004

This paper performs a historical review on aviation threats through a statistical survey. The impact factor, as a criterion to measure the seriousness of the threats occurred, is introduced and evaluated based on annual totals of hijacking and fatalities against aircraft 1948 through 2004. Also, the paper suggests processes of evaluating the level of threats and key functions for an effective management of the aviation security.