• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.6
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• pp.1602-1609
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• 1998

In this paper, the design and implementation of the novel RF front end circuit for CDMA based PCS phone is described. This novel scheme is realized by building the power amplifier module combined with duplexer. The dielectric filters which are parts of duplexer are broken up and relocated into the module. Electromagnetic analysis for via holes and coupling between narrow transmissio lines is icluded to design a circuit. The combined moule has been minimaturized to be as small as 1.5CC. It has satisfied IS-95 requirements for linearity performances of CDMA signal at 24-dBm output power as well as played apart as a duplexer. The operating current of about 95mA has been saved owing to both rearranging dielectric filters and limiting operating point to class-B by considering real working power range of CDMA phones.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.7
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• pp.1347-1353
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• 2015

We implemented a 10 Gb/s 4-channel vertical cavity surface emission lasers (VCSEL) driver array in a $0.13{\mu}m$ CMOS process technology. To enhance high current resolution, power dissipation, and chip space area, digital APC/AMC with time division sensing technology is primarily adopted. The measured -3 dB frequency bandwidth is 9.2 GHz; the small signal gain is 10.5 dB; the current resolution is 0.01 mA/step, suitable for the wavelength operation up to 10 Gb/s over a wide temperature range. The proposed APC and AMC demonstrate 5 to 20 mA of bias current control and 5 to 20 mA of modulation current control. The whole chip consumes 371 mW of low power under the maximum modulation and bias currents. The active chip size is $3.71{\times}1.3mm^2$.

• Journal of Auto-vehicle Safety Association
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• v.7 no.1
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• pp.7-12
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• 2015

NCAP(New Car Assessment Program) makes vehicle manufacturer improve safety performance through free competition and customers guarantee vehicle selection by providing information of vehicle safety. That's why it is important not only to meet the regulation, but also to cope with NCAP. EuroNCAP(European New Car Assessment Program) side tests have conducted by using Progressive MDB and Euro SID II in order to reproduce crash test between two vehicles over 10 years. However various researches report that Progressive MDB and Euro SID II do not reflect evolving vehicle design, impact performance and biofidelity of human. Therefore EuroNCAP has the plan to conduct AE-MDB side crash test using WorldSID which is more evolved from 2015 by replacing Progressive MDB and EuroSID II. Automobile manufacturers need to develop safety performance for new test closely. This paper is to find test set-up parameters which affect into dummy injury instead of restraint system and to research on its tendency. It is processed with mini and small car to know influence as changing vehicle size and also analyzed by DFSS(Design for six sigma) which is one of optimization tools. DFSS is vaildated by simulating CAE with L18 orthogonal array of 6 control factors adjustable as EuroNCAP requirement.

• Journal of the Korean Chemical Society
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• v.32 no.6
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• pp.543-548
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• 1988

The metal-support interaction was studied in 1∼5wt% copper supported on $\gamma-alumina$ and titania systems by temperature programmed reduction (TPR) and EPR. When the samples were treated with oxygen at $500^{\circ}C$, the relative area of H2-TPR peak at higher temperature increased with copper content for titania system whereas that of lower temperature increased for ${\gamma}$-alumina system. After oxygen treatment at $500^{\circ}C,\;{\gamma}$-alumina system showed a TPR peak at $300^{\circ}C$ while two peaks at 120 and $180^{\circ}C$ were found in titania system. A typical $Cu^{2+}$ EPR signal was observed on ${\gamma}$-alumina but very broad and small one on titania. From the results, it was suggested that the metal-support interaction increases in the order of silica < titania < ${\gamma}$-alumina and copper oxide has different loading characteristics depending on the supports.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.22 no.6
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• pp.641-647
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• 2011

This paper describes a design and fabrication of SDLVA. The SDLVA operates 0.5~2.0 GHz with -70~0 dBm dynamic range. The SDLVA is consisted of 5-stage RF block, 2-stage detector block and summation circuit using clamping op-amp to improve video linearity. The result of measure, SDLVA of RF path has over 73 dB small-signal gain and 10.1~12.2 dBm saturation power. The video path has 25 mV/ dB${\pm}$1.0 mV and under ${\pm}$1.5 dB video linearity.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.59-68
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• 2008

In this paper, we propose a method for selecting meaningful event packets from which can receive before anything else from seismograph according to allotted priority and estimate epicenter using selected packets. Event packets which received from each station will be evaluated with their onset time, signal period and SNR by statistical method and will be selected packets related with real earthquake's P-wave. And estimated epicenters using by 'Application of epicenter estimation using first P arrivals'. With local earthquakes occurred in 2007 were announced by KMA, collected event packets on earthquake happened date and selected p-wave related packets and estimated epicenter. After result of experiment, if an earthquake occurred within seismic networks, can estimate epicenter with small misfits just after event packets arrived from above 4 stations. Considering average distance of each station, in case of using all stations' data include other organization, can estimate and alert rapidly. It show this method is useful when construct a local earthquake early warning system later.

• Geophysics and Geophysical Exploration
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• v.15 no.4
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• pp.199-208
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• 2012

High-amplitude swell noises (HASN) are very difficult to eliminate from the marine seismic data. In this paper, we applied F-X filter and median filter in order to suppress HASN. Test data have been acquired on the northern offshore of the South Shetland Islands in December, 2010. Parts of data have been contaminated by HASN caused by bad weather during the cruise. We applied F-X filter and median filter to test data with HASN. After F-X filtering, most of non-coherent noises and small-amplitude swell noises are eliminated effectively but HASN are still remained significantly. With median filter, HASN was suppressed better than F-X filter, however some of non-coherent noises are still remains. We applied a cascade of two filters and results show HASN and non-coherent noises are suppressed effectively. After the cascade of two filtering, it is possible to define reflection layers clearly on the velocity spectrum and to produce better stacked section with a good signal-to-noise ratio.

• Journal of Ginseng Research
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• v.40 no.3
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• pp.285-291
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• 2016

Background: Ginsenosides have been shown to exert beneficial pharmacological effects on the central nervous, cardiovascular, and endocrine systems. We sought to determine whether total ginsenosides (TG) inhibit monocrotaline (MCT)-induced pulmonary hypertension and to elucidate the underlying mechanism. Methods: MCT-intoxicated rats were treated with gradient doses of TG, with or without $N^G$-nitro-$\small{L}$-arginine methyl ester. The levels of molecules involving the regulation of nitric oxide and mitogen-activated protein kinase pathways were determined. Results: TG ameliorated MCT-induced pulmonary hypertension in a dose-dependent manner, as assessed by the right ventricular systolic pressure, the right ventricular hypertrophy index, and pulmonary arterial remodeling. Furthermore, TG increased the levels of pulmonary nitric oxide, endothelial nitric oxide synthase, and cyclic guanosine monophosphate. Lastly, TG increased mitogen-activated protein kinase phosphatase-1 expression and promoted the dephosphorylation of extracellular signal-regulated protein kinases 1/2, p38 mitogen-activated protein kinase, and c-Jun NH2-terminal kinase 1/2. Conclusion: TG attenuates MCT-induced pulmonary hypertension, which may involve in part the regulation of nitric oxide and mitogen-activated protein kinase pathways.

• Korean Journal of Optics and Photonics
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• v.8 no.6
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• pp.500-505
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• 1997

Experimental amorphous photodiode is fabricated on CMOS IC using a-Si:H p-i-n structure. Amorphous photodiode is scuccessfully integrated on CMOS IC using amorphous Si produced by PECVD system. The PECVD system can deposit a-Si:H at low temperature so that photodiode can be integrated with CMOS IC structure without any process incompatibility. The fabricated amorphous photodiode has a breakdown voltage of below -20 V, a leakage current of about 1 $\mu\textrm{A}$, and turn-on voltage of 0.6~0.8 V. It is demonstrated that the photocurrent of optical signal can be turned on and off by a small voltage and the fabricated amorphous p-i-n photodiode can be used as an optical switch.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.25 no.9
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• pp.1400-1409
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• 2001

This paper describes a fiber optic sensor suitable for non-contact detection of ultrasonic waves. This sensor is based on a fiber optic Sagnac interferometer. Quadrature phase bias between two interfering laser beams in Sagnac loop is introduced by a polarization controller. A stable quadrature phase bias can be confirmed by observing the interferometer output versus phase bias. This method eliminates a digital signal processing for detection of ultrasonic waves using Sagnac interferometer. Interference intensity is affected by the frequency of ultrasonic waves and the time delay of Sagnac loop. Collimator is attached to the end of the probing fiber to focus the light beam onto the specimen surface and to collect the reflected light back into the fiber probe. Ultrasonic waves produced by conventional ultrasonic transducers are detected. This fiber optic sensor based on Sagnac interferometer is very effective for detection of small displacement with high frequency such as ultrasonic waves used in conventional non-destructive testing.