• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.3
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• pp.369-374
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• 2010

Linear motors are easily affected by load disturbances, force ripples, friction, and parameter variations because there are no mechanical transmissions that can reduce the effects of model uncertainties and external disturbance. In this study, a nonlinear adaptive controller to achieve high-speed/high-accuracy position control of a two-axis linear motor is designed. The operation of this controller is based on a cross-coupling algorithm. Nonlinear effects such as friction and force ripples are estimated and compensated for. An enhanced cross-coupling algorithm is proposed for effectively improving the biaxial contour accuracy while achieving closed-loop stability. The proposed controller is evaluated by performing computer simulations.

• The Journal of Natural Sciences
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• v.14 no.1
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• pp.39-50
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• 2004

T7 RNA polymerase is a single subunit RNA polymerase able to accomplish whole transcription process without auxiliary factors. In order to study transcription elongation mechanism of phage T7 RNA polymerse, stepwise walking of RNA polymerase was established by immobilizing biotinylated DNA template with streptavidin bead, series of active and stable elongation complexes were obtained, Transcripts were radio isotope labeled at the 16thm 17th and 18th nucleotide residues so stable elongation transcription complex of T7 RNA polymerase containing 22-40 nucleotide residues could be identified. We identified the positions of stablely formed transcription elongation complexes of termination site in intrinsic hairpin-independent PTH terminator sequence through the established stepwise walking of wild-type of mutant R173C T7 RNA polymerases. The results suggest that stable elongation transcription complexes were at the site of passing PTH terminator signal by mutant R173C RNA polymerase.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.9
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• pp.62-71
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• 2002

An intergral C-V converter is proposed to solve the nonlinearity problem of capacitive pressure sensors. The integral C-V converter consists of a switched-capacitor integrator and a switched-capacitor differential amplifier. It converts the sensor capacitance change which is inversely proportional to an applied pressure into a linear voltage output. Various PSPICE simulations prove that the convertor has excellent characteristics, such as low nonlinearity less than 0.01%/FS and low sensitivity to parallel offset capacitance and parasitic capacitance for the displacement range of sensor diaphragm set to 0 ${\sim}$ 90% of the initial distance between the electrodes in the simulation. We also show that the offset compensation and the gain trimming are easily achieved with the integral C-V converter.

• The Journal of Korean Association of Computer Education
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• v.20 no.2
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• pp.57-65
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• 2017

The world's senior population is on the rise. In particular, unlike the past seniors who were in the digital insensitivity class, the smart seniors who want to continue to use smart devices and the Internet are emerging. Although the definition of senior is merely defined as a senior group, research on the characteristics of seniors has been done in psychology studies, but research using data based senior cognitive response is only at an early stage. In order to provide contents according to the cognitive characteristics of Smart Senior, there is a need to classify the cognitive characteristics of Smart Senior well. Therefore, this paper suggests a data - driven senior cognitive response modeling method that helps the enjoyment of culture for seniors through classification of cognitive responses to smart seniors.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.1
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• pp.53-62
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• 2016

Extreme wind speeds at four sites including Mokpo, Gunsan, Incheon and Jeju near the Western Coast have been estimated with a tool of Monte Carlo simulation and typhoon data. Results of sensitivity analysis show that closeness between distance to the eye and the radius to maximum wind is most sensitive. While location angle and pressure deficit are sensitive too, but translation velocity is not. A standard typhoon, which results in extreme wind speeds having various return period, can be constructed by combination of parameter informations of each site. Then, with a numerical modelling of the typhoon, extreme surge heights having the same return period can also be obtained. To be added, by analysing the data which only including those based on navigable semicircle, it is possible to produce a standard typhoon which could result in setting-down of sea level.

• Nuclear Engineering and Technology
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• v.15 no.4
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• pp.236-247
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• 1983

Analyzed are the the DNBR(Departure from Nucleate Boiling Ratio) sensitivities to variations in various PWR operating parameters utilizing the Korea Nuclear Unit 1(KNU-1) design and operating data. Studied parameters in the analysis are core power level, system pressure, core inlet flow rate, core inlet temperature, enthalpy rise hot channel factor, and axial power peaking factor and axial offset. The calculations are performed using the steady state and transient thermal-hydraulics computer program, COBRA-IV-K, which is the revised version of COBRA-IV-i that has been adapted, partially modified and verified at KAERI. A reference case is established based on the design and operating condition of the KNU-1 reactor core, and this provides a basis for the subsequent sensitivity analysis. From the calculation results it is concluded that the most sensitive parameter in the DNBR thermal design is the coolant core inlet temperature while the axial power peaking factor is the least sensitive.

• Korean Journal of Optics and Photonics
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• v.18 no.3
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• pp.216-220
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• 2007

A widely tunable add/drop filter composed of double ring resonators is implemented with high-index-contrast polymer waveguide. To enhance the productivity, directional couplers are designed to have good fabrication tolerance. The refractive indices of the core and cladding in the 1550 nm wavelength are 1.51 and 1.378, respectively. Drop response in comparison with neighborhood peak gets enhanced by more than 2.9 dB at the wavelength where both rings resonate. This filter can be used to build widely tunable laser diode through hybrid-integration with reflective SOA.

• Journal of the Korea Society for Simulation
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• v.27 no.3
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• pp.117-129
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• 2018

In this paper we will discuss two different layout concepts which can be applied to rail-vehicle assembly factory. The existing system is based on the traditional flow line, and the suggested system is based on the fixed position layout. The main factors which affect on the system performances are the variation of process time, shortage rate of part and the shortage period. Simulation experiments indicate that the fixed position layout is better with respect to the throughput, mean flow time per vehicle and the mean flow time per fleet. Furthermore, the fixed position layout is more robust than the flow line because performance measures are insensitive to the variations of factors.

• Journal of the Korean Magnetics Society
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• v.14 no.4
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• pp.120-126
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• 2004

In order to understand the temperature dependence of magnetic properties of $F_{84}Nb_{16}$(wt.%) thin films, ferromagnetic resonance experiments have been carried out. The ferromagnetic resonance spectra for all temperatures consist of several volume modes and one (or two) surface modes. It is suggested that both surface of the film have a perpendicular hard axis to the film plane (negative surface magnetic anisotropy). Saturation magnetization coincides with the Block's T$\^$2/3/ and spectroscopic splitting factor is almost constant in the temperature range from 113 K to 293 K. The surface magnetic anisotropy constant K$\_$s2/ of the film-substrate interface increased with decreasing temperature in the temperature range from 233 K to 293 K. The surface magnetic anisotropy constant K$\_$s1/ of the air-substrate interface decreased from -0.322 erg/$\textrm{cm}^2$ to -0.394 erg/$\textrm{cm}^2$ as the temperature decreased to 253 K and was almost constant below 233 K.233 K.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1350-1354
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• 2010

SWAT 모형에서는 토양수량을 고려하여 유출곡선지수법에 따라 지표유출량과 침투량을 계산하고, 계산된 침투량이 토양수대가 받을 수 있는 최대용량인 토양수 최대보수용량(soil water capacity)을 초과할 경우에는 그 초과분을 강제적으로 토양수량에 더해지도록 처리하고 있다. 즉, 초과침투량이 연직 아래로만 유입되는 것으로 간주하고 있다. 이러한 방식은 경사가 매우 완만한 경우에는 적합하다고 할 수 있으나, 국내 유역에서와 같이 비교적 유역 경사가 급한 경우에는 지표유출량이 작게 계산될 수 있으며 특히 집중호우시 강우에 대한 유출 응답이 둔감하게 모의되어 홍수기 큰 강우로 인해 급격하게 증가하는 유출량을 잘 모사하지 못하게 되는 경우가 발생한다. 따라서 본 연구에서는 홍수기 큰 강우에 대해서 유출량이 민감하게 반응할 수 있도록 초과침투량 재분배 모듈($\underline{R}$edistributing $\underline{EX}$cessive $\underline{INF}$iltration module, 이하 SWAT-REXINF)을 개발하였다. 이 모듈은 토양층의 보수능을 초과하는 침투량 처리 방식을 개선한 것으로 지표유출의 집중시간과 토양수의 침루 유하시간의 상대적인 크기에 따라 초과침투량을 분배하여 지표유출량과 침투량에 할당하는 방식을 취하고 있다. 개발 모듈 SWAT-REXINF을 기 개발한 시간가중평균 유출곡선지수법에 의한 지표유출계산법과 접합-분리 방식의 토양층 구조화 기법 등의 유출계산 개선 기법과 접목하여 그 효과를 충주댐 유역에 대해 분석하였다. 시간가중평균 유출곡선지수법에 의한 지표유출계산법과 접합-분리 방식의 토양층 구조화 기법 등 다른 유출 개선 기법과 혼용하여 적용할 경우에는 지표유출량이 약 2배 증가, 첨두유량은 20~50% 증가하는 등 개선 효과가 매우 크게 나타났다. 모형 개선으로 인해서 강우량에 대한 유출량의 응답 민감도를 증가시켜 유출수문곡선의 증감을 보다 용이하게 모의할 수 있고 정확도 또한 높일 수 있을 것으로 판단된다.