• Title/Summary/Keyword: 차분형식

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Probabilistic Risk Assessment of Coastal Structures using LHS-based Reliability Analysis Method (LHS기반 신뢰성해석 기법을 이용한 해안구조물의 확률론적 위험도평가)

  • Huh, Jung-Won;Jung, Hong-Woo;Ahn, Jin-Hee;An, Sung-Wook
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.6
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    • pp.72-79
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    • 2015
  • An efficient and practical reliability evaluation method is proposed for the coastal structures in this paper. It is capable of evaluating reliability of real complicated coastal structures considering uncertainties in various sources of design parameters, such as wave and current loads, resistance-related design variables including Young's modulus and compressive strength of the reinforced concrete, soil parameters, and boundary conditions. It is developed by intelligently integrating the Latin Hypercube sampling (LHS), Monte Carlo simulation (MCS) and the finite element method (FEM). The LHS-based MCS is used to significantly reduce the computational effort by limiting the number of simulation cycles required for the reliability evaluation. The applicability and efficiency of the proposed method were verified using a caisson-type breakwater structure in the numerical example.

DMD based modal analysis and prediction of Kirchhoff-Love plate (DMD기반 Kirchhoff-Love 판의 모드 분석과 수치해 예측)

  • Shin, Seong-Yoon;Jo, Gwanghyun;Bae, Seok-Chan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.26 no.11
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    • pp.1586-1591
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    • 2022
  • Kirchhoff-Love plate (KLP) equation is a well established theory for a description of a deformation of a thin plate under certain outer source. Meanwhile, analysis of a vibrating plate in a frequency domain is important in terms of obtaining the main frequency/eigenfunctions and predicting the vibration of plate. Among various modal analysis methods, dynamic mode decomposition (DMD) is one of the efficient data-driven methods. In this work, we carry out DMD based modal analysis for KLP where thin plate is under effects of sine-type outer force. We first construct discrete time series of KLP solutions based on a finite difference method (FDM). Over 720,000 number of FDM-generated solutions, we select only 500 number of solutions for the DMD implementation. We report the resulting DMD-modes for KLP. Also, we show how DMD can be used to predict KLP solutions in an efficient way.

Experimental Design of S box and G function strong with attacks in SEED-type cipher (SEED 형식 암호에서 공격에 강한 S 박스와 G 함수의 실험적 설계)

  • 박창수;송홍복;조경연
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.1
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    • pp.123-136
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    • 2004
  • In this paper, complexity and regularity of polynomial multiplication over $GF({2^n})$ are defined by using Hamming weight of rows and columns of the matrix ever GF(2) which represents polynomial multiplication. It is shown experimentally that in order to construct the block cipher robust against differential cryptanalysis, polynomial multiplication of substitution layer and the permutation layer should have high complexity and high regularity. With result of the experiment, a way of constituting S box and G function is suggested in the block cipher whose structure is similar to SEED, which is KOREA standard of 128-bit block cipher. S box can be formed with a nonlinear function and an affine transform. Nonlinear function must be strong with differential attack and linear attack, and it consists of an inverse number over $GF({2^8})$ which has neither a fixed pout, whose input and output are the same except 0 and 1, nor an opposite fixed number, whose output is one`s complement of the input. Affine transform can be constituted so that the input/output correlation can be the lowest and there can be no fixed point or opposite fixed point. G function undergoes linear transform with 4 S-box outputs using the matrix of 4${\times}$4 over $GF({2^8})$. The components in the matrix of linear transformation have high complexity and high regularity. Furthermore, G function can be constituted so that MDS(Maximum Distance Separable) code can be formed, SAC(Strict Avalanche Criterion) can be met, and there can be no weak input where a fixed point an opposite fixed point, and output can be two`s complement of input. The primitive polynomials of nonlinear function affine transform and linear transformation are different each other. The S box and G function suggested in this paper can be used as a constituent of the block cipher with high security, in that they are strong with differential attack and linear attack with no weak input and they are excellent at diffusion.

Real Life Emotions in Koreeda Hirokazu's Still Walking (사실적인 감정의 미학 : 고레에다 히로카즈의 <걸어도 걸어도>를 중심으로)

  • Min, Hwan-Ki;Nam, Yeon-Kyoung
    • Cartoon and Animation Studies
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    • s.27
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    • pp.199-219
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    • 2012
  • An innovative narrative film-making always came out of conflict and negotiation between reality and film form. A lesson we learn from their film-making is a certain reality is no more possible to be dealt with by conventional narrative. A dialectic between a real life and a representation drives a certain film-makers to make films. Kore-eda Hirokazu is internationally known as developing his own method of meshing of so-called real life and the artifice of film. As He began his career as a documentary film-maker, made several documentaries for TV and then turned to his feature film-making, documentary film-making defines the basic stance in all of his film-making. He in particular emphasized that he considered the fundamental ethical standpoint of documentary to be filming from the standpoint that one does not - or cannot - know the person one is filming. And therefore even in his fiction films he avoids subjective cinematic structures that offer easy access to the internal states of his characters. He makes his audience observe the internal states of his characters from the outside with his narrative strategy. This article will analyse two documentary films of Koreeda Hirokazu in such a way that his documentaries meshes a real life and the artifice of film and then explores such a fiction film like that changes its documentary methods into narrative strategy for the same effect on the audience.

Applicability evaluation of aerodynamic approaches for evaporation estimation using pan evaporation data (증발접시 증발량자료를 이용한 공기동력학적 증발량 산정 방법의 적용성 평가)

  • Rim, Chang-Soo
    • Journal of Korea Water Resources Association
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    • v.50 no.11
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    • pp.781-793
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    • 2017
  • In this study, applicabilities of aerodynamic approaches for the estimation of pan evaporation were evaluated on 56 study stations in South Korea. To accomplish this study purpose, previous researchers' evaporation estimation equations based on aerodynamic approaches were grouped into seven generalized evaporation models. Furthermore, four multiple linear regression (MLR) models were developed and tested. The independent variables of MLR models are meteorological variables such as wind speed, vapor pressure deficit, air temperature, and atmospheric pressure. These meteorological variables are required for the application of aerodynamic approaches. In order to consider the effect of autocorrelation, MLR models were developed after differencing variables. The applicability of MLR models with differenced variables was compared with that of MLR models with undifferenced variables and the comparison results showed no significant difference between the two methods. The study results have indicated that there is strong correlation between estimated pan evaporation (using aerodynamic models and MLR models) and measured pan evaporation. However, pan evaporation are overestimated during August, September, October, November, and December. Most of meteorological variables that are used for MLR models show statistical significance in the estimation of pan evaporation. Vapor pressure deficit was turned out to be the most significant meteorological variable. The second most significant variable was air temperature; wind speed was the third most significant variable, followed by atmospheric pressure.