• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.7 s.349
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• pp.29-37
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• 2006

This paper presents a new analytical model to suppress RLC resonance effects which inevitably occur in power/ground lines due to on-chip decoupling capacitor and other interconnect circuit parasitics (i.e., package inductance, on-chip decoupling capacitor, and output drivers, etc.). To characterize the resonance effects, the resonance frequency of the circuit is accurately estimated in an analytical manner. Thereby, a decoupling capacitor size to suppress the resonance for a suitable circuit operation is accurately determined by using the estimated resonance frequency. The developed novel design methodology is verified by using $0.18{\mu}m$ process-based-HSPICE simulation.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.503-510
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• 2012

Microwave radar can penetrate cloud cover regardless of weather conditions and can be used day and night. Especially a A ground-based polarimetric scatterometer operating at multiple frequencies can continuously monitor the crop conditions. We analyzed scattering characteristics of rice and soybean using pauli decomposition method. Surface scattering (${\alpha}$) is the dominant component over the entire stages for all bands and pauli decomposition value was the highest for L-band. Double bounce scattering (${\beta}$) and volume scattering (${\gamma}$) were approximately equal for C-band and volume scattering was higher than double bounce scattering for X-band in rice field. In soybean, double bounce scattering becomes higher than volume scattering during the R2 stage (DOY 224) and there was a significant difference between the two components after the R4 stage (DOY 242) for L-band. The maximum growth stage of soybean can also be detected using L-band double bounce scattering. The peak of double bounce effect coincides with the peak of growth biophysical variables on DOY 271. We found that pauli decomposition can provide insight on the relative magnitude of different scattering mechanisms during the rice and soybean growth cycle.

• Journal of the Korean GEO-environmental Society
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• v.12 no.3
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• pp.47-54
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• 2011

The rockfall protection fence installed to secure safety against rockfall occurring in cut slope has been designed under the condition with 50kJ of impact energy arising when the 400kg of rock block is falling from 12.5m height. However, in falling case of bigger rock block or from higher place, it is hard to be secure of safety with existing rockfall protection fence. Using the rockfall program, safety analysis for rockfall is conducted in this paper by changing slope height, separating distance from fence, and slope angle, according to rock block sizes. In the result of analysis, when a 400kg of rock block which is designed load is fallen, the existing rockfall protection fence with 2.5m height can secure most of rock fall except some cases for the slope having 20m or less hight, whereas for more than 20m height, the fallen rock is frequently splattered over the rockfall protection fence, as well as the impact energy of rockfall may exceed designed impact energy. Therefore, in the design of rock fence, it is considered appropriate to design that after conducting safety review for rockfall according to the ground conditions, evaluating the bounce height and impact energy of rock fall, and then installing appropriate rockfall protection fence would be applicable rather than just following standards based design drawing.

• Journal of electromagnetic engineering and science
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• v.5 no.4
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• pp.193-196
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• 2005

The DC power-bus for the PCB is loaded with metal walls on its selected sides and is characterized electromagnetically. This is a novel concept of approach to mitigate the spurious resonance and finally signal integrity problems. In particular, the peak at DC, which is always in the way to secure parallel-plates' EMC, can be completely removed by the proposed method. Through the findings of this study, the effect of metal-loading of the power-bus will be presented along with the impression that the suggested technique can tackle the headaches of signal integrity, ground bounce, EMIs.

• Proceedings of the Korea Electromagnetic Engineering Society Conference
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• 2002.11a
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• pp.340-343
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• 2002

Electromagnetic(EM) radiation problems and their possible solutions are addressed in this paper for the split power plane of high-speed digital systems. Stitching and decoupling capacitors are proved to be very effective fur reducing signal noise, ground bounce as well as electromagnetic radiation from the split power plane. Simulations based on 3D-Finite Difference Time Domain (FDTD) method are utilized for the analysis of practical high frequency multi-layered PC main board

• Journal of electromagnetic engineering and science
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• v.2 no.2
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• pp.75-80
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• 2002

Signal integrity problems and their possible solutions are addressed in this paper for split power plane of high-speed digital systems. Stitching and decoupling capacitors are proved to be very effective for reducing signal noise, ground bounce as well as electromagnetic radiation from the split power plane. Simulations based on 3D-Finite Difference Time Domain (FDTD) method are utilized for the analysis of practical high frequency multi-layered PC main board.

• Journal of the Microelectronics and Packaging Society
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• v.4 no.2
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• pp.25-32
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• 1997

대용량, 고속 정보처리가 요구되는 System의 모듈은 Data 처리의 고속성 및 회로의 고집적이 가능한 MCM의 형태로 구현되어 ATM, GPS 및 PCS 등의 분야에 광범위하게 응 용되고 있다. 위와 같은 High Speed 응용분야에서의 System 성능은 Interconnect Line의 전달지연, 임피던스 부정합에 의한 신호 반사 손실. 신호선 간의 Crosstalk, Ground Bounce 등의 현상에 대한 최적화 여부에 결정적인 영향을 받는다. 그러나 Interconnect의 특성상 정 형이 존재하지 않으므로 추상적인 Library를 구축하는 형식으로 접근할 수밖에 없으며 이를 위하여 여러기본 구조를 정의한후 각 Dimension을 변수로 두고 해석 결과를 합성하여 Database화하는 접근방식이다. 본 논문에서는 MCM-D 공정을 이용하여 Interconnect Line 특성을 분석하고 Database화 하기 위한 Test Pattern을 구현하고 Time Domain reflectometry(TDR)을 이용하여 그특성들을 측정 분석하였다. Test pattern 제작은 MCM-D 공정으로 최소선폭 27$\mu$m, Via Hole 75$\mu$m으로 형성하였고 2 Layer Signal과 GND로 총 3Layer를 구현하였다. 특성분석을 위해 TDR장비와 모데링 및 Simulation S/W인 IPA 510 을 사용하였다. 이를 통해 MCM-D를 이용한 공정에서 Interconcet Line의 고주파 특성을 측정하고 정량화하여 LIbrary를 제작할수 있었다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.18 no.2 s.117
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• pp.206-212
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• 2007

In this paper, a novel power/ground plane using the hybrid-cell electromagnetic band-gap(EBG) structure is proposed for the wide-band suppression of the ground bound noise(GBN) or simultaneous switching noise(SSN). The -30 dB stopband of the proposed structure starts from a few hundred MHz where the GBN/SSN energy is dominant. The distinctive features of this new structure are the thin spiral strip line and hybrid-cells. They realize the enhanced inductance and the shorter period of the EBG lattice. As a result, the lower cut-off frequency and bandwidth of the -30 dB stopband becomes lower and wider, respectively. In addition, the proposed structure has smaller number of resonance modes between power/ground planes and performs a low EMI behavior compared with the reference board.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.28 no.12
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• pp.982-992
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• 2017

In this paper, we introduce a method of selection for the optimal transmission polarization of a W-band seeker through the extraction of the one-dimensional scattering center of a ground tank target. We calculated the surface scattering and edge scattering using the shooting and bouncing ray tracing method of the CST A-solver. Based on 4-channel RCS data, using the one-dimensional RELAX algorithm, which is a kind of spectral estimation technique, scattering centers of ground targets were extracted. According to the changes in the polarization state and look angle, we compared and analyzed the scattering center results. Through simulation, we verified that the scattering center results can be applied when feature vectors are used for target recognition.

• International Journal of Automotive Technology
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• v.8 no.6
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• pp.731-744
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• 2007

A method for dynamic analysis and design calculation of a Powertrain Mounting System(PMS) including Hydraulic Engine Mounts(HEM) is developed with the aim of controlling powertrain motion and reducing low-frequency vibration in pitch and bounce modes. Here the pitch mode of the powertrain is defined as the mode rotating around the crankshaft of an engine for a transversely mounted powertrain. The powertrain is modeled as a rigid body connected to rigid ground by rubber mounts and/or HEMs. A mount is simplified as a three-dimensional spring with damping elements in its Local Coordinate System(LCS). The relation between force and displacement of each mount in its LCS is usually nonlinear and is simplified as piecewise linear in five ranges in this paper. An equation for estimating displacements of the powertrain center of gravity(C.G.) under static or quasi-static load is developed using Newton's second law, and an iterative algorithm is presented to calculate the displacements. Also an equation for analyzing the dynamic response of the powertrain under ground and engine shake excitations is derived using Newton's second law. Formulae for calculating reaction forces and displacements at each mount are presented. A generic PMS with four rubber mounts or two rubber mounts and two HEMs are used to validate the dynamic analysis and design calculation methods. Calculated displacements of the powertrain C.G. under static or quasi-static loads show that a powertrain motion can meet the displacement limits by properly selecting the stiffness and coordinates of the tuning points of each mount in its LCS using the calculation methods developed in this paper. Simulation results of the dynamic responses of a powertrain C.G. and the reaction forces at mounts demonstrate that resonance peaks can be reduced effectively with HEMs designed on the basis of the proposed methods.