• Journal of the Korean Geophysical Society
• /
• v.3 no.4
• /
• pp.251-260
• /
• 2000

Applicabilities of two numerical methods, the 2-dimensional and the 3-dimensional method, are evaluated to inverse test results obtained from the underwater SASW(Spectral -Analysis-of-Surface-Waves) method. As a result of this study, it has been found that the 2-dimensional method can supposed to be applicable for the cases where stiffness of soil layer increases gradually with depth, and the stiffness is relatively low. For the other cases, however, it has been concluded that the 3-dimensional method needs to be applied to determine realistic theoretical dispersion curves. An example is also shown that in situ soil profile underwater is estimated from experimental dispersion curves using the 3-dimensional method. As a results, it can be concluded that the underwater SASW method can be effectively applied to explore the underwater soil condition.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.17 no.7 s.110
• /
• pp.684-693
• /
• 2006

In this paper, the SA (Specific Absorption) distribution in a human head, exposed to wideband pulse EMF, has been analyzed by taking into account the dispersion characteristics of biological tissues. The dispersive properties of biological tissues are characterized by the 4th Cole-Cole model. Currently, there is no dispersive FDTD algorithm to implement the 4th Cole-Cole model accurately. Thus, in this paper the FDTD methods with the dispersive algorithm for the 1st-order Cole-Cole model and the 3rd-order Debye model were used for SA analysis. The validity of each model has been investigated first, and then the effects of dispersion on SA distribution have been studied.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.52-56
• /
• 2010

본 연구에서는 지진해일의 전파 과정을 모의함에 있어 선형 천수방정식의 수치분산을 이용하는 기법이 아닌 선형 Boussinesq 방정식을 직접 차분하는 유한차분기법을 제안하였다. 지배방적식과 차분식의 일치성을 해석하기 위해 이산화 오차를 확인하고, 수치해의 안정적 수렴여부를 판단하기 위해 Von neumann 안정성 해석을 수행하였다. 또한 기법의 정확성을 검증하기 위하여 Gauss 분포의 초기 자유수면변위를 갖는 문제에 적용하여 선형 Boussinesq 방정식의 해석해와 비교하였다. 그 결과 기존의 선형 천수방정식을 차분화한 수치모형에 비하여 정확한 결과를 제공하였고 분산보정기법을 이용한 수치모형과 동일한 정확도를 보였으나 본 수치모형을 이용했을 때 비교적 넓은 범위의 조건에서 정확도 높은 결과를 제공하였다.

• Electric Engineers Magazine
• /
• s.309
• /
• pp.24-28
• /
• 2008

이번호에서는 태양광발전시스템에 적용하고 있는 분산형 전원 배전계통 연계기술기준을 소개하기로 한다. 지금까지 국내 분산형 전원 배전계통 기술기준은 한국전력공사에서 마련한 기준을 중심으로 적용하고 있다. 참고로 이웃 일본의 경우 정부에서 정한 전기설비기술기준 해석에서 정하여 객관적이며 균형 있게 적용하면서 국가적으로 발전적인 부분을 담고 있다는 점을 강조하고 싶다.

• Aerospace Engineering and Technology
• /
• v.13 no.1
• /
• pp.70-75
• /
• 2014

Programs of energy balance, mode analysis and transient analysis for a liquid rocket engine have been introduced. The analysis methods have been verified through comparison between the present results, and the results of the other program and experimental data. An energy balance analysis is used for engine system design at the early development phase. A mode analysis is used for decision of engine operation conditions and test conditions, and studying deviation of an engine performance. A transient analysis can predict a propellant flow rate, thrust, impulse at transient phase. It is essential to establish a startup/shut down sequence. The analysis programs will be used to develop the engines of KSLV-II.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2012.05a
• /
• pp.80-82
• /
• 2012

In this paper, we present electromagnetic modeling to design unclonable PUFs with frequency-dependant materials corresponding to Debye dispersion. To demonstrate FDTD calculations consider that 1-D problem of pulsed plane wave traveling in free space normally incident on air-silicon material interface. The pulse traveling wave at a vacuum-medium interface were reflected, and transmitted wave were dissipated. As a result, 1-D PUF with Debye dispersion material structure can be applied and FDTD calculation for PUF modeling is a good approximation.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.16 no.6
• /
• pp.1141-1147
• /
• 2012

Electromagnetic analysis to design unclonable PUFs with frequency-dependant materials with Debye dispersion was considered. To simulate FDTD calculations consider that 1-D problem of pulsed plane wave traveling in free space normally incident on air-silicon material interface on dielectric substrate. The pulse traveling wave at a vacuum-medium interface was reflected, and transmitted wave was dissipated. As a result, 1-D PUF modeling with Debye dispersion on dielectric substrate structure can be applied and FDTD calculation for PUF modeling is a good approximation.

• Environmental and Resource Economics Review
• /
• v.5 no.2
• /
• pp.185-202
• /
• 1996

일반적으로 국민경제의 상태를 평가할 때, 경제성장, 물가상승률, 고용사정 및 국제수지 등 각 부문의 성과를 종합적으로 고려한다. 이들 각 부문의 성과는 개선되거나 악화되는데 있어서 동일한 추세를 보이기도 하지만 서로 상반된 움직임을 보이기도 한다. 또한 각 부문간에는 상충관계가 존재하기도 하므로, 부문간의 조화를 달성하기가 매우 어렵다는 사실도 잘 알려져 있다. 본 논문은 평균 분산 개념을 이용하여, 국민경제의 전체적 상황 및 부문간 격치를 반영하면서 직관적으로도 이해하기 쉬운 경제성과지수를 제시하고 이를 이용하여 석유파동 등이 각국경제에 미친 영향을 파악한다. 먼저 경제 각 부문별로 성과를 나타내는 경제지표로부터 시계열 평균과 분산을 계산하고 이를 이용하여 각 부문의 연도별 성과를 지수화한다. 이와같이 계산된 각 부문 지수들의 연도별 평균을 구하고 이를 해당연도의 평균적 경제성과로 해석한다. 또한 연도별로 부문별 지수간의 분산을 계산하여 이를 각 연도별 경제부문간 편차로 해석한다. 평균지수가 높을수록, 그리고 분산지수가 낮을수록 경제성과가 우수하다고 할 수 있다. 본 논문에서 제시된 방법에 따라 한국, 미국, 일본, 대만의 평균 분산 지수를 도출하여 비교 분석한 결과, 동지수가 각국의 경제실상을 잘 나타내고 있으며 두차례의 석유파동이 각국에 미친 영향을 비교하는데 유용하게 활용될 수 있음을 확인하였다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.17 no.8
• /
• pp.1755-1760
• /
• 2013

In this paper, when the pulses propagate on a uniform microstrip line, the distortion of pulse signal caused by dispersion is investigated in time domain. We analyzed dispersion characteristics according to dielectric constant and structure of transmission line, and compared propagating characteristics for square and gaussian pulse according to pulse width, pulse amplitude, and propagation velocity. The results of this paper are compatible to the trade-off determination of relative permittivity, substrate height, strip width and pulse width of signal pulse when a design of MIC and MMIC is necessary.

• Journal of the Korean Geotechnical Society
• /
• v.21 no.4
• /
• pp.155-165
• /
• 2005

Love wave and Rayleigh wave are the major elastic waves belonging to the category of the surface wave. Those waves are used to determine the ground stiffness profile using their dispersion characteristics. The fact that Love wave is not contaminated by P-wave makes Love wave superior to Rayleigh wave and other body waves. Therefore, the information that Love wave carries is more distinct and clearer than that of others. Based on theoretical research, the joint inversion analysis that uses the dispersion information of both Love and Rayleigh wave was proposed. Numerical analysis, theoretical model test, and field test were performed to verify the joint inversion analysis. Results from 2D, 3D finite element analysis were compared with those from the transfer matrix method in the numerical analysis. On the other hand, the difference of results from each inversion analysis was investigated in the theoretical model analysis. Finally, practical applicability of the joint inversion analysis was verified by performing field test. As a result, it is confirmed that considering dispersion information of each wave simultaneously prevents excessive divergence and improves accuracy.