• Journal of the Korea Institute of Military Science and Technology
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• v.12 no.2
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• pp.222-227
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• 2009

The bias characteristics due to the changes of temperature and temperature gradient of fiber coil are investigated in fiber-optic gyroscope. The bias performance is degraded with the changes of temperature and temperature gradient of fiber coil. The temperature compensation using both the temperature-dependent bias measurement and the temperature-induced error model of fiber-optic gyroscope improves the bias stability about 3 times as much as the uncompensated original case, which leads to very stable bias performance over the temperature range from $-35^{\circ}C$ to $+77^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1911-1913
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• 2001

전위차 측정형 바이오 센서는 기준전극에 대한 센서 전극의 전기화학적 전위를 정확하게 측정하여야 하므로 기준전극의 안정성이 매우 중요하다. 기준전극의 전위는 전해질 용액 내의 염소 음이온 농도에 영향을 받으나 다행히도 혈액 내의 염소 음이온 농도는 거의 변화가 없으므로 혈액 속에서의 은/염화은 기준전극의 전위도 거의 변화가 없다. 본 연구에서는, 사진석판 (Photolithography) 공정을 이용하여 실리콘 표면 및 다공질 실리콘 표면에 은/염화은 박막 기준전극을 제작하고 시료 용액에서의 drift, 안정성, 재현성 등에 대한 특성을 고찰하였고, SEM, AES, EDX 스펙트럼 등을 이용하여 전극의 표면을 분석하였다. 시료 용액의 염소 음이온 농도를 $10^{-4}$M에서 1M까지 변화시켜가며 기준 전극의 전위를 측정한 결과 약 50mV/pCl의 기울기를 얻었으며 이것은 Nernst식을 잘 따르는 결과이다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.322-322
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• 2010

In this paper, we propose a novel type valveless micro-pump that uses extensional vibration mode of traveling wave as a volume transporting means for solving some problems about check valves, essential parts of usual pumps. The proposed pump consists of two piezoelectric ceramic rings and a metal body located in the middle of them respectively. Because the drift of bended surface that results from the traveling wave excitation controls the fluid flow, check valves are not needed in this pump model. In accordance with the variation of the pump body dimension, we analyzed the vibration displacement characteristics of pump model, determined the optimal design condition, fabricated the prototype pump from the analysis results and evaluated its efficiency.

• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.41-44
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• 2004

This paper describes the electron transport characteristics in $SF_6$-He gas calculated for range of E/N values from 50${\sim}$700[Td] by the Monte Carlo simulation(MCS) and Boltzmann equation(BEq) method using a set of electron collision cross sections determined by the authors and the values of electron swarm parameters are obtained by TOF method. The results gained that the values of the electron swarm parameters such as the electron drift velocity. the electron ionization or attachment coefficients. longitudinal and transverse diffusion coefficients agree with the experimental and theoretical for a range of E/N.

• International Journal of Concrete Structures and Materials
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• v.7 no.2
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• pp.135-153
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• 2013

This study investigates the direct displacement based design (DDBD) approach for different types of reinforced concrete structural systems including single moment-resisting, dual wall-frame and dual steel-braced systems. In this methodology, the displacement profile is calculated and the equivalent single degree of freedom system is then modeled considering the damping characteristics of each member. Having calculated the effective period and secant stiffness of the structure, the base shear is obtained, based on which the design process can be carried out. For each system three frames are designed using DDBD approach. The frames are then analyzed using nonlinear time-history analysis with 7 earthquake accelerograms and the damage index is investigated through lateral drift profile of the models. Results of the analyses and comparison of the nonlinear time-history analysis results indicate efficiency of the DDBD approach for different reinforced concrete structural systems.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.453-457
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• 2001

One of the major limitations of productivity and quality in metal cutting is the machining accuracy of machine tools. The machining accuracy is affected by geometric and thermal errors of the machine tools. In this study, the compensation device is manufactured in order to compensate thermal error of machine tools under the real-time. This paper models of the thermal errors for error analysis and develops on-the-machine measurement system by which the volumetric error are measured and compensated. The thermal error is modeled by means of angularity errors of a column and thermal drift error of the spindle unit which are measured by the touch probe unit with a star type styluses, a designed spherical ball artifact, and five gap sensors. In order to compensate thermal characteristics under several operating conditions, experiments performed with five gap sensors and manufactured compensation device on the horizontal machining center.

• Earthquakes and Structures
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• v.7 no.4
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• pp.553-570
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• 2014

In this study, nonlinear dynamic analyses were performed in order to evaluate and compare the structural response of different type of moment resisting frame buildings equipped with conventional braces (CBs) and buckling restrained braces (BRBs) subjected to near-field ground motions. For this, the case study frames, namely, ordinary moment-resisting frame (OMRF) and special moment-resisting frame (SMRF) having two equal bays of 6 m and a total height of 20 m were utilized. Then, CBs and BRBs were inserted in the bays of the existing frames. As a brace pattern, diagonal type with different configurations were used for the braced frame structures. For the earthquake excitation, artificial pulses equivalent to Northridge and Kobe earthquake records were taken into account. The results in terms of the inter-story drift index, global damage index, base shear, top shear, damage index, and plastification were discussed. The analysis of the results indicated a considerable improvement in the structural performance of the existing frames with the inclusion of conventional and especially buckling-restrained braces.

• Journal of IKEEE
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• v.17 no.3
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• pp.360-364
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• 2013

The maximum breakdown voltage's characteristic within the Super Junction MOSFET structure comes from N-Drift and P-Pillar's charge balance. By developing P-Pillar from Planar MOSFET, it was confirmed that the breakdown voltage is improved through charge balance, and by setting the gate voltage at 10V, the characteristic comparisons of Planar MOSFET and Super Junction MOSFET are shown in picture 6. The results show that it had the same breakdown voltage as Planar MOSFET which increased temperature resistance by 87.4% at $.019{\Omega}cm^2$ which shows that by the temperature resistance increasing, the power module's power dissipation improved.

• 제어로봇시스템학회:학술대회논문집
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• 1992.10a
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• pp.692-697
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• 1992

This study concerns about the orbit prediction and orbit determination of Korean future communication satellite, called "Moogunghwa", which will be motioned in the geo-stationary orbit. Perturbation effect on the satellite orbit due to nonspherical geopotential term, lunar and solar gravity, drag force of the atmosphere and solar radiation pressure was investigated. Cowell's method is used for orbit prediction. Orbit determination was performed by using EKF which is suitable for real-time orbit determination. The result shows that the characteristics of the satellite orbit has drift. So the periodic control time and control value in the view of the periodic of error can be provided. The orbit determination demonstrated the effectiveness since the convergence performance on the position and velocity error , and state error standard deviation is reasonable.easonable.

• Proceedings of the IEEK Conference
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• 2000.06e
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• pp.113-116
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• 2000

In this paper presents the portable wireless ECG data detection and diagnosis system based on discreet wavelet transform. An algorithm based on wavelet transform suitable for real time implementation has been developed in order to detect ECG characteristics. In particular, QRS complex, S and T waves may be distinguished form noise, baseline drift or artifacts. Proposed telemetry system that a transmitting media using radio frequency(RF) for the middle range measurement of the physiological signals and receiving media using optical for electromagnetic interference problem. A standard hi-directional serial communication interface between the telemetry system and a personal computer or laptop, allows read-time controlling, diagnosing and monitoring of system. A portable telemetry system within a size. of 65${\times}$125${\times}$45mm consists of three parts: a digital signal processing part for physiological signal detect or diagnose, RF transmitter for data transfer and a optical receiver for command receive. Advantages of proposed telemetry system is wireless middle range(50m) FM transmission, reduce electromagnetic interference to a minimum. which enables a comfortable diagnosis system at home.