• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.10
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• pp.33-46
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• 2015

In this paper, we predicts the analog and digital circuit performance of FinFETs that are scaled down following the ITRS(International technology roadmap for semiconductors). For accurate prediction of the circuit performance of scaled down devices, accurate parasitic resistance and capacitance analytical models are developed and their accuracies are within 2 % compared to 3D TCAD simulation results. The parasitic capacitance models are developed using conformal mapping, and the parasitic resistance models are enhanced to include the fin extension length($L_{ext}$) with respect to the default parasitic resistance model of BSIM-CMG. A new algorithm is developed to fit the DC characteristics of BSIM-CMG to the reference DC data. The proposed capacitance and resistance models are implemented inside BSIM-CMG to replace the default parasitic model, and SPICE simulations are performed to predict circuit performances such as $f_T$, $f_{MAX}$, ring oscillators and common source amplifier. Using the proposed parasitic capacitance and resistance model, the device and circuit performances are quantitatively predicted down to 5 nm FinFET transistors. As the FinFET technology scales, due to the improvement in both DC characteristics and the parasitic elements, the circuit performance will improve.

• Journal of the KSME
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• v.57 no.6
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• pp.32-36
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• 2017

이 글에서는 전산모사를 이용하여 나노스케일 소재의 역학적 특성을 이해하고자 하는 연구 분야를 소개하고자 한다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.64-64
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• 2003

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.04a
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• pp.56-57
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• 2006

• Journal of the KSME
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• v.57 no.10
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• pp.38-42
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• 2017

이 글에서는 나노 스케일의 채널이 갖는 특성으로부터 기인하는 이온 및 물질의 전달현상을 이해하기 위한 수치 해석적 연구를 소개하고자 한다.

• Science of Emotion and Sensibility
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• v.8 no.4
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• pp.415-422
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• 2005

The purpose of the present study was to investigate the differences of nonlinear characteristics of electroencephalogram (EEG) depending on different sensitivities of behavioral activation system (BAS) and behavioral inhibition system (BIS) of young and elderly groups. The EEGs from Fpl and Fp2 electrodes were recorded during resting condition. The young and elderly groups consisted of 19 and 31 healthy right-handed volunteers, respectively. We estimated 1/f scaling exponent which reflects the nonlinear dynamical complexity of EEG. As results, we found the differences of 1/f scaling exponent between young ant elderly BAS sensitive groups. The 1/f scaling exponent of young BAS sensitive group showed significantly higher values than those of elderly BAS sensitive group at the left prefrontal area (Fpl). The young BAS sensitive group had also a tendency to higher 1/f scaling exponent at the right prefrontal area (Fp2). Decrease of the 1/f scaling exponent indicates the increase of complexity and the decrease of the amount of information related to the statistical distribution. Therefore, the elderly BAS sensitive group has higher complexity than young BAS sensitive group, though they were all classified as BAS sensitive group by BAS/BIS scale. Our results suggest the possibility of correlation between BAS sensitivity an4 age.

• Journal of the Korean Geographical Society
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• v.48 no.6
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• pp.879-896
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• 2013

The assessed land values and housing prices have been widely utilized as a basic information for the land and house trades and for evaluating governmental and local taxes. However, there exists a price difference in actual markets between the assessment level and assessed land values or housing prices. This paper emphasizes the spatial mismatch between the assessed land values and housing market prices and particularly addresses the following two aspects by focusing on spatial effects of the modifiable areal units, which would substantially affect the estimation of the assessed land values and housing prices. First, we examine the spatial distributions of the assessed land values and housing market prices, and the gap between those prices, on the basis of the aggregated spatial units(i.e., aggregation districts). Second, we explore the scale effect of the MAUP(modifiable areal unit problem) generally embedded in estimating the prices of the sampled standard lands and houses, and calibrating the correction index for the land values and housing prices for the individuals. For the application, we analysed the land values and housing prices in Seoul utilizing GIS and statistical software. As a result, some spatial clusters that the housing market prices are significantly higher than the assessed land values were identified at a finer geographic level. Also, it was empirically revealed that the statistical results from the regression of regional variables on the assessed land values for the individuals are significantly affected by the aggregation levels of the spatial units.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.31 no.3
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• pp.133-140
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• 2018

This paper is concerned with the 2-D micostructure generation for $Ni-A{\ell}_2O_3$ dual-phase composite materials and the numerical analysis of mechanical characteristic of hierarchical models of microstructure which are defined in terms of the scale of microstructure. The microstructures of dual-phase composite materials were generated by applying the mathematical RMDF(random morphology description functions) technique to a 2-D RVE of composite materials. And, the hierarchical models of microstructure were defined by the number of Gaussian points. Meanwhile, the volume fractions of metal and ceramic particles were set by adjusting the level of RMD functions. The microstructures which were generated by RMDF technique are definitely random even though the total number of Gaussian points is the same. The randomly generated microstructures were applied to a 2-D beam model, and the variation of normal and shear stresses to the scale of microstructure was numerically investigated. In addition, through the crack analyses, the influence of RMDF randomness and Gauss point number on the crack-tip stress is investigated.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.463-473
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• 2005

In this paper, we propose Adaptive GOP Structure to enhance the coding performance of scalable video coding in JVT. Adaptive GOP Structure considers temporal variances of video sequence. In general, SVC encodes a video sequence with fixed GOP size. The coding performance is varying according to the temporal variance of a video sequence. Thus, Adaptive GOP Structure method is proposed. It selects GOP size adaptively by considering temporal variance of video sequence. In the experiments, the propose method showed the enhanced coding performance in most sequences. The PSNR gain of Crew sequence is up to 0.63 dB.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.36.1-36.1
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• 2011

1차원 양자 구속 효과로 인해 우수한 전하 전송 특성을 갖는 나노선을 차세대 전자소자에 응용하기 위한 일환으로, 실리콘 기판 상에 동일한 실리콘 나노선을 성장하고 이의 미세구조 특징을 분석하였다. 실리콘 나노선은 Au 시드층을 형성한 후 화학기상증착법을 이용한 VLS (vapor-liquid-solid) 공법으로 성장시켰으며, 시드층의 크기에 따른 나노선의 구조 특성을 이미지 프로세싱을 통해 통계분석하였다. 성장된 실리콘 나노선의 결정구조와 성분을 고해상도 투과전자현미경과 EDAX를 이용하여 분석하였으며, 성장 온도 조건에 따른 나노선의 morphology 특성도 실시하였다. 그 결과 Au 시드층의 성분이 나노선과 기판의 계면에서 상당 부분 잔류함과, 성장된 나노선에는 쌍정 결함(twin defect) 등의 결정구조 변화가 수반됨을 알 수 있었다. 또한 금속 시드층의 평균 입도와 성장 온도 및 소스 가스 유량 조절함으로써 실리콘 나노선의 직경과 길이를 최적화 할 수 있었다. 이를 통해 향후 공정 스케일 다운의 한계 상황에 도달하고 있는 반도체 트랜지스터 소자를 대체할 수 있는 나노선 반도체 소자에 대한 공정기술 개발과 이를 이용한 다양한 응용 분야도 동시에 제시할 수 있게 되었다.