• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.547-552
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• 1996

확률론적 방법을 이용한 MCNP4A 전산코드를 이용하여 두꺼운 차폐체내에서 효과적인 분산감소기법에 대하여 가장 단순화된 모델을 이용하여 고찰하여 보았다. 등방점선원과 이를 둘러싼 반경 50cm의 납차폐체를 계산을 위한 모빌로 사용하여 차폐체 내부 각 영역과 외부에서의 평균선속을 계산하였다. 분산감소기법으로는 구역분할법과 Exponential transform을 적용하여 각 구역에서의 분산의 변화를 비교하였다. 계산결과 두꺼운 차폐체문제에서는 exponential transform이 가장 효과적인 분산감소기법으로 나타났고 이때 구역분할법을 통하여서는 상대오차의 크기를 더욱 줄일 수 있었다.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.820-823
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• 1996

In contrast to parts of relatively simple shapes, it is important to match their cross-sectional shapes during mating parts of complicated shapes. It requires the 2.pi. information along their matching boundary to figure out their relative geometrical shapes. In this paper, we propose a method measuring a misalignment at the interface during mating parts with the complicated shapes by using the omnidirectional image sensing system(OLSSA). Also we carried out experiments in order to prove the method, and the results show the feasibility.

• Proceedings of the IEEK Conference
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• 1998.06a
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• pp.457-460
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• 1998

단 채널 MOSFET 소자의 드레인 전압-드레인 전류 특성을 예측하기 위해서 caughey-thomas 이동도 모델을 수치적으로 구현하는 방법을 제안한다. 구현된 caughey-thomas 모델의 정확한 특성을 검증하기 위해서 0.5[.mu.m]의 설계규칙을 가즌 ASIC용 공정으로 n-MOSFET과 p-MOSFET을 제작하였다. 전자 및 정공의 포화속도 값이 각각 6.2*10/sup 6/[cm/sec] 과 1.034*10/sup 7/[cm/sec]인 경우에 채널길이가 0.5[.mu.m] 이상인 n-MOSFET과 p-MOSFET의 드레인 전압-드레인 전류특성의 모의실험 결과는 측정값에 비하여 10% 이내의 상대오차를 보였다.

• Proceedings of the IEEK Conference
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• 2001.06b
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• pp.157-160
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• 2001

소자 내부의 전위와 전자 및 정공 의사 페르미 준위에 따른 반송자의 정확한 농도를 얻기 위해 Fermi-Dirac통계를 구현하는 방법을 제시하였다. 또한 Fermi-Dirac통계를 고려하여 반도체 방정식을 이산화하는 방법을 제안한다. 제안된 방법을 검증하기 위해 전력 바이폴라 접합 트랜지스터를 제작하였으며 모의 실험 결과 컬렉터-에미터 전압 대 컬렉터 전류는 현재 업계에서 상용화된 소자의 실측치와 비교하여 최대 15%이내의 상대오차를 보였다.

• KCID journal
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• v.3 no.2
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• pp.44-52
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• 1996

To make a real hydraulic simulation model, Hazen-Williams' coefficient must be calibrated using the measured discharges and hydraulic head loss. In this paper, calibrating method of Hazen-Williams' coefficient was proposed for pipeline system. The calibra

• Journal of Korea Water Resources Association
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• v.39 no.8 s.169
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• pp.659-668
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• 2006

The uncertainty of the risk of failure of hydraulic structures can be determined by estimating the variance of the risk of failure based on the methods of moments, probability weighted moments, and maximum likelihood assuming that the underlying model is the Gumbel distribution. In this paper, the variance of the risk of failure was derived. Monte Carlo simulation was peformed to verify the characteristics of the derived formulas for various sample size, design life, nonexceedance probability, and variation coefficient. As the results, PWM showed the smallest relative bias and root mean square error than the others while ML showed the smallest ones for relatively large sample siBes regardless of design life and nonexceedance probability. Also, it was found that variation coefficient does not effect on the relative bias and relative root mean square error.

• Analytical Science and Technology
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• v.27 no.3
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• pp.140-146
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• 2014

An internal standard was used in PCID (post column isotope dilution) to improve the accuracy and precision in quantification of various chemical species. The error occurring in the column was the largest in HPLC-ICP/MS (high performance liquid chromatography-inductively coupled plasma/mass spectrometry) when PCID and other traditional quantification methods were compared with each other. Internal standard was effective in correcting the loss of sample in the column to improve accuracy and precision. When applied to SeMet, using MeSecys or $Se^{4+}$ as an internal standard, relative errors were reduced from 31% and 13% to less than 1%, while standard deviations were reduced from 5.1% and 6.9% to 1.5% and 0.2%, respectively. Positive aspects of using an internal standard in PCID were compared with other quantitative techniques and discussed in detail.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.2
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• pp.100-108
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• 2014

In this paper, we design SSD(simultaneous single band duplex) system using RF(radio frequency) cancellation and digital cancellation. we analyze characteristic of residual self-interference after RF Cancellation signal when error of phase shifter occur in RF cancellation. When phase shifter error of $0^{\circ}$, $0.5^{\circ}$, $1^{\circ}$ and $2^{\circ}$ occur in RF cancellation, residual self-interference signal power after RF cancellation is bigger than desired signal power of distant station. So, it is impossible to receive transmit data of distant station. but we confirm that it is possible to receive transmit data of distant station by digital cancellation with frame structure. Also, in digital cancellation with frame structure, if residual self-interference signal after RF cancellation is too large then LMS algorithm requires more time to estimate self-interference channel. That is, performance degradation occurs because self-interference channel estimation has not completed in estimation frame.

• Journal of Korea Water Resources Association
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• v.43 no.11
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• pp.977-984
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• 2010

In order to determine the optimal sediment discharge formula for Hyeongsan river, some statistical approaches have been applied to analyze the simulated results of long-term bed change by HEC-6. The field measurements have been conducted to obtain the data for model calibration and verification such as sediment discharge, bed material, and channel geometry. Several sediment discharge formulae have been verified according to the bias, RMSE, RRMSE, discrepancy ratio, and S/N ratio of bed change along the thalweg. Comparing the formulae, Laursen formula(modified by Copeland) have shown the best performance to simulate the long-term bed change of Hyeongsan river.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.5
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• pp.399-405
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• 2007

Providing a precise positioning information is the primary characteristics of GPS. The relative positioning technique which utilizes the common measurements between a GPS reference station and a user is generally used to do the generation of a precise positioning. But if user is far from a GPS reference site, the properties of medium penetrated by GPS signals will be different from each other, It is difficult to eliminate the error sources such as the ionosphere and the troposphere effectively by the double differencing method. In this study the additional error correction values with the ionosphere and the troposphere to the data processing have applied. As a result, the positioning accuracy of fourteen out of seventeen testing sites were improved by appling the error correction values. We also analysed the improved rate of the positioning accuracy by the baseline.