• JSTS:Journal of Semiconductor Technology and Science
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• 제13권5호
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• pp.511-515
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• 2013

A Monte Carlo (MC) simulation study has been done in order to investigate the effects of line-edge-roughness (LER) induced by either 1P1E (single-patterning and single-etching) or 2P2E (double-patterning and double-etching) on fully-depleted silicon-on-insulator (FDSOI) tri-gate metal-oxide-semiconductor field-effect transistors (MOSFETs). Three parameters for characterizing the LER profile [i.e., root-mean square deviation (${\sigma}$), correlation length (${\zeta}$), and fractal dimension (D)] are extracted from the image-processed scanning electron microscopy (SEM) image for each photolithography method. It is experimentally verified that two parameters (i.e., ${\sigma}$ and D) are almost the same in each case, but the correlation length in the 2P2E case is longer than that in the 1P1E case. The 2P2E-LER-induced $V_TH$ variation in FDSOI tri-gate MOSFETs is smaller than the 1P1E-LER-induced $V_TH$ variation. The total random variation in $V_TH$, however, is very dependent on the other major random variation sources, such as random dopant fluctuation (RDF) and work-function variation (WFV).

• 터널과지하공간
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• 제10권3호
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• pp.486-491
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• 2000

발파 진동은 보통 지반진동속도로 계측되며, 발파설계나 구조물의 피해 산정에 적절하게 사용된다. 그러나 발파 진동에 의한 인체의 반응이나 가축의 피해 산정 등의 문제에서는 현행 소음진동규제법에서 명시하는 바, 인체의 감각적 감응척도에 충실한 진동레벨을 주로 사용하므로 변환문제가 발생한다. 본 연구에서는 발파 진동 계측기기로 계측한 데이터를 디지털 필터로 처리하여, 진동레벨로 변환하는 프로그램을 개발하고, 이를 단순조화진동과 실제 발파계측결과에 적용하였다. 그 결과, 단순조화진동은 물론이고 국내에서 널리 사용되고 있는 Instantel Inc.의 Blastmate series에서 계측된 진동데이터도 정밀도 높은 진동레벨로 변환이 가능하였다. 비슷한 정밀도로 계측결과를 ASCII file로 송출할 수 있는 기종에서 계측된 자료도 같은 정도로 처리할 수 있을 것으로 판정되었다.

• 한국암반공학회:학술대회논문집
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• 한국암반공학회 2000년도 암반공학문제의 수치해석(Numerical Analysis in Rock Engineering Problems)
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• pp.241-246
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• 2000

발파 진동은 보통 지반진동속도로 계측되며, 발파설계나 구조물의 피해 산정에 적절하게 사용된다. 그러나 발파 진동에 의한 인체의 반응이나 가축의 피해 산정 등의 문제에서는 현행 소음진동규제법에서 명시하는 바, 인체의 감각적 감응척도에 충실한 진동레벨을 주로 사용하므로 변환문제가 발생한다. 본 연구에서는 발파 진동 계측기기로 계측한 데이터를 디지털 필터로 처리하여, 진동레벨로 변환하는 프로그램을 개발하고, 이를 단순조화진동과 실제 발파계측결과에 적용하였다. 그 결과, 단순조화진동은 물론이고 국내에서 널리 사용되고 있는 Instantel Inc.의 Blastmate series에서 계측된 진동데이터도 정밀도 높은 진동레벨로 변환이 가능하였다. 비슷한 정밀도로 계측결과를 ASCII file로 송출할 수 있는 기종에서 계측된 자료도 같은 정도로 처리할 수 있을 것으로 판정되었다

• 천문학회보
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• 제35권2호
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• pp.75.1-75.1
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• 2010

The nature and origin of the intergalactic magnetic field (IGMF) are an outstanding problem of cosmology, yet they are not well understood. Measuring Faraday rotation (RM) is one of a few promising methods to explore the IGMF. We have theoretically investigated RM using a model of the IGMF based on a MHD turbulence dynamo (Ryu et al. 2008; Cho et al. 2009). In the previous KAS meeting, we reported the results for the present-day local universe; for instance, the probability distribution function (PDF) of ${\mid}RM{\mid}$ follows the lognormal distribution, the root mean square (rms) value for filaments is ~1 rad m^{-2}, and the power spectrum peaks at ~1 h^{-1} Mpc scale. In this talk, we extend our study of RM; by stacking simulation data up to redshift z=5 and taking account of the redshift distribution of radio sources, we have reproduced an observable view of RM through filaments against background radio sources. Our findings are as follows. The inducement of RM is a random walk process, so that the rms of RM increases with increasing path length. The rms value of RM for filaments reaches several rad m^{-2}. The PDF still follows the lognormal distribution, and the power spectrum of RM peaks at less than degree scale. Our predictions of RM could be tested, for instance, with LOFAR, ASKAP, MEERKAT, and SKA.

• 전자공학회논문지A
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• 제32A권12호
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• pp.184-197
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• 1995

In this paper, high speed IC package-to-package interconnections are modeled as lossless multiconductor transmission lines operating in the TEM mode. And, three mathematical algorithms for computing electrical parameters of the lossless multiconductor transmission lines are described. A semi-analytic Green's function method is used in computing per unit length capacitance and inductance matrices, a matrix square root algorithm based on the QR algorithm is used in computing a characteristic impedance matrix, and a matrix algorithm based on the theory of M-matrix is used in computing a diagonally matched load impedance matrix. These algorithms are implemented in a computer program DIME (DIagonally Matched Load Impedance Extractor) which computes electrical parameters of the lossless multiconductor transmission lines. Also, to illustrate the concept of design database for high speed IC package-to-package interconnection, a database for the multi conductor strip transmission lines system is constructed. This database is constructed with a sufficiently small number of nodes using the multi-dimensional cubic spline interpolation algorithm. The maximum interpolation error for diagonally matched load impedance matrix extraction from the database is 1.3 %.

• 대기
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• 제22권3호
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• pp.287-298
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• 2012

The predictability of heavy precipitation over the Korean Peninsula is studied using THORPEX Interactive Grand Global Ensemble (TIGGE) data. The performance of the six ensemble models is compared through the inconsistency (or jumpiness) and Root Mean Square Error (RMSE) for MSLP, T850 and H500. Grand Ensemble (GE) of the three best ensemble models (ECMWF, UKMO and CMA) with equal weight and without bias correction is consisted. The jumpiness calculated in this study indicates that the GE is more consistent than each single ensemble model. Brier Score (BS) of precipitation also shows that the GE outperforms. The GE is used for a case study of a heavy rainfall event in Korean Peninsula on 9 July 2009. The probability forecast of precipitation using 90 members of the GE and the percentage of 90 members exceeding 90 percentile in climatological Probability Density Function (PDF) of observed precipitation are calculated. As the GE is excellent in possibility of potential detection of heavy rainfall, GE is more skillful than the single ensemble model and can lead to a heavy rainfall warning in medium-range. If the performance of each single ensemble model is also improved, GE can provide better performance.

• 한국토양비료학회지
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• 제46권4호
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• pp.245-252
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• 2013

Leaf area index (LAI) is important in explaining the ability of crops to intercept solar energy for biomass production, amount of plant transpiration, and in understanding the impact of crop management practices on crop growth. This paper describes a procedure for estimating LAI as a function of image-derived vegetation indices from temporal series of RapidEye imagery obtained from 2010 to 2012 using empirical models in a rice plain in Seosan, Chungcheongnam-do. Rice plants were sampled every two weeks to investigate LAI, fresh and dry biomass from late May to early October. RapidEye images were taken from June to September every year and corrected geometrically and atmospherically to calculate normalized difference vegetation index (NDVI). Linear, exponential, and expolinear models were developed to relate temporal satellite NDVIs to measured LAI. The expolinear model provided more accurate results to predict LAI than linear or exponential models based on root mean square error. The LAI distribution was in strong agreement with the field measurements in terms of geographical variation and relative numerical values when RapidEye imagery was applied to expolinear model. The spatial trend of LAI corresponded with the variation in the vegetation growth condition.

• 한국환경과학회지
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• 제24권4호
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• pp.515-524
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• 2015

The estimation of groundwater usage in Jeju island is important to understand hydrologic cycle system and to plan management of water resource because large amounts of groundwater have been used for agricultural and domestic purpose. The model has been developed to estimate agricultural groundwater usage for garlic at uplands and citrus at orchards raising outdoors using the soil water balance model from FAO 56, respectively. The total amount of water supplied for the crop evapotranspiration and the multipurpose function such as sprout promotion can be simulated by the model. However, due to the discrepancy of water use in initial stage between calculated and observed, the model was calibrated and verified using actual groundwater usage monitoring data for 3.5 years (2011.6 to 2014.12) at three uplands for garlic and three orchards for citrus. Consequently, it would be concluded that the model simulated efficiently actual water usage in that root mean square (RMS) and normalized RMS of the validation stage were less than 8.99 mm and 2.43%, respectively, in two different conditions.

• 대한조선학회논문집
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• 제47권6호
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• pp.813-820
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• 2010

The spread mooring system for FPSO is developed to explore deep sea area, in which swell is dominant. It is known that the tension response of mooring lines in this sea area shows bimodal spectrum. Assuming normal distribution of tension profile and Rayleigh distribution of tension amplitude, the power spectral density function (PSD) of the mooring tension under the bimodal stationary random process is applied for the calculation of spectrum fatigue. Three popular methods, which are simple summation method, combined spectrum method and Jioa-Moan method, are used to combine fatigue damages from bimodal spectrum characteristics. Each damage value is compared with damage using Rainflow Cycle Counting (RCC) method which is believed to be close to exact solution. Vanmarcke' parameter and RMS(Root Mean Square) ratio are employed to assess relative damage variations between from RCC method and from three combination methods. Finally the most reliable fatigue damage combining method for spread mooring system is suggested.

• 한국정보통신학회논문지
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• 제17권8호
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• pp.1891-1898
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• 2013

3차원 그래픽 API인 OpenGL과 Direct3D를 효율적으로 처리하기 위해 sine, cosine, 역수, 역제곱근, 지수 및 로그 연산을 처리하는 부동소수점 연산회로를 설계하였다. 고속 연산과 2 ulp 보다 작은 오차를 만족시키기 위해 2차 최대최소 근사 방식과 테이블 룩업 방식을 사용하였다. 설계된 회로는 65nm CMOS 표준 셀 조건에서 2.3-ns의 최대 지연시간을 갖고 있으며, 약 23,300 게이트로 구성된다. 최대 400 MFLOPS의 연산 성능과 높은 정밀도로, 설계한 연산회로는 3차원 모바일 그래픽 분야에 효율적으로 적용 가능하다.