• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.9
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• pp.1013-1022
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• 2010

In this paper, we propose a C-band radiometer for remote sensing of land surface temperature and present its experiment results using asphalt as target. Total power type is selected for high sensitivity and low power consumption, super-heterodyne type is selected for stable high gain. A radiometer designed at 5.1 GHz to have operating bandwidth of 110 MHz has system gain of 59 dB, noise figure of 2.7 dB and receiving sensitivity of 0.45 K. We have measured surface temperature on asphalt by using implemented system and thermometer. Analysis data of each measurement results show that a radiometer operates linearly with output voltage variation rate of 6 $mV/^{\circ}C$. As a result, we verified validity of a developed C-band radiometer for remote sensing of land surface temperature.

• Transactions of the Korean Society of Mechanical Engineers
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• v.17 no.6
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• pp.1381-1388
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• 1993

This paper presents a method for the simultaneous optimal design of structural and control systems. Sensitivities of performance index with respect to structural design variables are analyzed. The structural design variables are optimized to minimize the performance index by use of conjugate gradient method. The method is applied to a half model of an active vehicle suspension system with elastic body moving on a randomly profiled road. The suspension control force of an optimally controlled system in the presence of measurement errors are calculated by use of linear quadratic Gaussian control theory and Kalman filter theory. The performance index contains ride comfort, road holding and working space of suspension. The structural design variables taken are stiffness, daming properties and the position of the suspension system. The random road profile considered as colored noise is shaped from white noise by use of shaping filter. The performance of an optimal simultaneous structure/control system is compared with that of an optimal controlled system.

• Fire Science and Engineering
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• v.26 no.3
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• pp.79-84
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• 2012

In this study thermal characteristics of heat-responsive element considering conduction, convection and rate of change of element using Response Time Index (RTI) applied to sensitivity test of sprinkler head at home and aborad are theoretically investigated. Analytic solution of temperature distributions with radial direction and time is obtained form energy transport equations, non-homogeneous 2th order partial differential equation, applying to constant wall temperature and symmetric condition in order to analyze thermal characteristics of heat-responsive element for circular cylindrical geometry. Base on the results, the analytic method of this study is fundamental data to practical use for sensitivity test of sprinkler head and design of heat-responsive element.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.145-150
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• 2023

Non-uniform optical taper waveguides have been widely used as devices for high-efficiency mode coupling, as they are integrated with single-mode optical fibers or photonic crystal waveguides. In this paper, we present a new platform for chemical sensing and bio-sensing using optical taper waveguides with these characteristics. The principle of operation is based on the coupling efficiency and interference properties of optical directional coupler (DC) and multi-mode interference coupler (MMIC). First, the curvature characteristics of taper sections of DC and MMIC is explained, and the design specifications of optimized taper waveguide to increase waveguide sensitivity is selected. Next, the sensor response to the change in refractive index of sensing analyte is numerically analyzed. Numerical results show that as the length of couplers increases, the effective index per change in refractive index unit (RIU) of analyte increases, and that sensitivity can be tuned using taper DC and MMIC design techniques.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.505-511
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• 2018

Purpose : This study investigated the visual functions of drivers aged over 65 year olds and drivers aged 50~65 year olds. In addition, difference of visual functions between professional drivers and normal drivers were investigated. Methods : Forty Driver aged over 65 year olds and 67 drivers aged less than 67 year olds were participated. All participants had more than 5 years of driving experiences and had no ocular pathology. Demographic data(gender, job, age, body condition) and visual functions such as contrast sensitivity(CS), stereopsis, glare recovery time and discomfort glare index were measured. Results : Constrast sensivity under photopic condition was higher with bus driver group. In addition, difference of CS at 12cpd and 18cpd were signifcantly different between normal drivers(1.57) and bus drivers(1.70) (p<0.05). There was no significant difference for glare recovery time, despite of trend of longer recovery time with age. Discomfort glare index was significantly different that normal drivers with more than 65 year olds had 3, taxi and truck driver presented almost 5 index score (p<0.05). Conclusion : Analysis of visual function of elderly drivers, it was confirmed that their visual functions decreased with age. Therefore, visual function tests such as CS, discomfort glare index and stereopsis in addition to current available test may need to be considered for drivers aged over 65.

• The Journal of the Petrological Society of Korea
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• v.10 no.3
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• pp.172-178
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• 2001

K-Ar dating system of Korea Basic Science Institute (KBSI) was installed in 1997 and has been used since then. The system consists of high temperature graphite furnace, gas purification system, and mass spectrometer with data acquisition system. K-Ar age is determined by the measurement of the concentrations of Ar and K through isotope dilution method using $^{38}Ar$ as spike and flame spectroscopy, respectively. The accuracy and reliability for the K-Ar age are checked using the several K-Ar standard materials. Although the exact age determination for young samples of less than 1 Ma is hampered by small fluctuations of sensitivity and mass discrimination, the present system yields the reliable K-Ar age compared to the standard materials of Tertiary and Mesozoic age. The measurements for the SORI93 biotite with the recommended K-Ar age of $92.6\pm$0.6 Ma and Bern4M muscovite of $18.5\pm$0.6 Ma yield the reliable age of $92.1\pm$1.1 Ma and $17.8\pm$0.2 Ma, respectively.

• Journal of Sensor Science and Technology
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• v.11 no.4
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• pp.247-253
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• 2002

For fabrication of the pyroelectric IR sensor $(Pb,La)TiO_3(PLT)$/$LiTaO_3$/(LTO)/PLT ferroelectric thin films was deposited by rf magnetron sputtering followed by rapid thermal annealing and the crystallinity as a function of annealing temperature and time was investigated. Permittivity and dielectric loss factor of ferroelectric thin films as a function of c-axis preffered orientation was measured. Also pyroelectric coefficient of ferroelectric thin films with largest c-axis preffered orientation was measured and obtain figure of merit of voltage response($F_V$) and detectivity($F_D$). In this case $F_V$, $F_D$ was $5.63{\times}10^{-10}\;C{\cdot}cm/J$, $1.98{\times}10^{-8}\;C{\cdot}cm/J$, respectively.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.14 no.2
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• pp.148-156
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• 2003

This paper describes the RF performance issues of UE for W-CDMA system based on 3 GPP specifications. The parameters of transmitter and receiver are derived from the viewpoint of RF performance. In order for UE to achieve high performance, the transceiver performance requirements such as ACLR, EVM, Peak Code Domain Error, spectrum emission mask, frequency error stability and TX power control dynamic range for transmitter and reference sensitivity level, blocking characteristics, noise figure, ACS, AGC dynamic range for receiver are considered. On the basis of the required parameters, the UE RF transceiver is implemented and then the evaluation of RF performance is accomplished through practical test scenarios.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.603-607
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• 2006

최근 산불발생이 증가하고, 그에 따른 피해가 증가하고 있다. 또한 산불 발생지역의 토양침식으로 인한 2차적인 재해위험이 예상됨에 따라 산불 지역의 토양침식과 영향인자들에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 낙산사 산불지역의 산지사면에 10개의 소규모 조사구를 설치하고 강우에 따른 토사유출량을 조사하였다. 토양침식 매개변수를 강우인자(강우량, 강우강도, 강우에너지), 지형인자(면적, 사면경사, 사면길이, 길이경사인자), 식생인자(전체피복도, 식생지수), 토양인자(투수계수, 유효입경, 유기물함량, 토심)로 구분하여 각각의 토양침식에 대한 관계를 분석하고, 시간경과에 따른 토양침식의 관계도 분석하였다. 강우강도와 강우량이 커짐에 따라 토양침식민감도에 대한 식생피복도의 영향이 더욱 가중되며, 식생 회복이 빠른 지역과 그렇지 않은 지역에서의 시간경과에 따른 누적 토양침식량의 변화는 크게 차이를 보였다. 낙산사 산불지역에서의 강우에 따른 토양침식은 강우에너지와 식생피복도의 관계가 가장 높았다.

• Journal of IKEEE
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• v.19 no.3
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• pp.371-377
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• 2015

This paper is about the RF transceiver designed and implementation for common data link. The trasmitter is configured as a frequency up-converter, a power amplifier and a duplexer. The receiver is configured as a duplxer, a frequency down-converter and a low noise amplifier. The maximum transmission distance, the reception sensitivity is designed to meet the electrical and temperature characteristics and the like. Using a modeling and simulation in order to meet the requirements of the RF transceiver has been designed and implemented. Transmitting output power and Noise Figure has been measured with 38.58dBm and 5.5dB, respectively. All of the electrical and temperature specifications was meet. Was confirmed all of the requirement specification by electrical characteristics test and temperature characteristics test.