• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.277-277
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• 2012

국립기상연구소(National Institute of Meteorological Research; NIMR)는 기상청 이중편파 레이더 현업운영에 대비하여 2009년 X-band 연구용 이중편파 레이더를 도입하였고, 편파변수의 산출과 대기수상체 분류를 포함한 강수추정 등의 효용 가능성에 대한 연구를 지난 2년간 수행하고 있다. 이중편파 레이더는 반사도( )뿐만 아니라 차등반사도($Z_R$), 비차등 위상($K_{DP}$), 상관계수($_v$)등의 편파 변수의 산출로 강우감쇠보정과 기상에코-비기상의 에코(ground clutter, insects, birds, chaff)의 구별이 가능하다. 이러한 장점들을 이용해 레이더 자료품질 개선과 정량적 강수추정의 상당한 개선에 도움이 된다. 본 연구에서는 강수추정 관계식 R-Z, 감쇠 보정된 R-Z, R-$K_{DP}$ 관계식을 이용하여 레이더 관측 반경 내에 존재 하는 81개의 지상 우량계 자료와 강수량 추정의 정확도 비교 검증을 실시하였다. 그리고 Fuzzy logic 기법을 이용한 대기수상체 분류 알고리즘을 사용하였고 관측사례는 2011년 수도권 관측을 통해 강설/강수 에코 구별과 우박에코 사례를 분석하였다. 본 연구를 통해 이중 편파 레이더에서 산출된 고품질의 레이더기상자료를 기반으로 현업 예보지원 및 정량적 강우예측 향상에도 기여할 것으로 사료된다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.1
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• pp.70-76
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• 2019

Ultra Wideband (UWB) Radar is a high-resolution radar for short distance detection which uses signals transmitted and received by each antennas in order to detect a target. It is possible to detect the respiration and heartbeat of a person without contact It is getting more and more often utilized since it is not affected by physical environment. In this paper, we implement an algorithm to detect human respiration and heartbeat rate using UWB radar signal. We process radar signals reflected from human body using Median filter, Kalman filter, Band Pass filter and so on. We also use CZT to extract breathing and heart rate. ECG (Electrocardiogram) was used for comparison of heartbeat data and we confirm that each data of ECG and UWB Radar were more than 98% identical each other.

• Bulletin of the Korean Chemical Society
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• v.31 no.2
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• pp.344-350
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• 2010

The improved photocatalytic performance of a carbon/$TiO_2$ composite was studied for the Bisphenol A (BPA) decomposition. Titanium tetraisopropoxide (TTIP) and a rice husk from Korea were heterogeneously mixed as the titanium and carbon sources, respectively, for 3 h at room temperature, and then thermally treated at $600^{\circ}C$ for 1 h in $H_2$ gas. The transmission electron microscopy (TEM) images revealed that the bulk carbon partially covered the $TiO_2$ particles, and the amount that was covered increased with the addition of the rice husk. The acquired carbon/$TiO_2$ composite exhibited an anatase structure and a novel peak at $2{\theta}=32^{\circ}$, which was assigned to bulk carbon. The specific surface area was significantly enhanced to 123~164 $m^2/g$ in the carbon/$TiO_2$ composite, compared to $32.43m^2/g$ for the pure $TiO_2$. The X-ray photoelectron spectroscopy (XPS) results showed that the Ti-O bond was weaker in the carbon/$TiO_2$ composite than in the pure $TiO_2$, resulting in an easier electron transition from the Ti valence band to the conduction band. The carbon/$TiO_2$ composite absorbed over the whole UV-visible range, whereas the absorption band in the pure$TiO_2$ was only observed in the UV range. These results agreed well with an electrostatic force microscopy (EFM) study that showed that the electrons were rapidly transferred to the surface of the carbon/$TiO_2$ composite compared to the pure $TiO_2$. The photocatalytic performance of the BPA removal was optimized at a Ti:C ratio of 9.5:0.5, and this photocatalytic composite completely decomposed 10.0 ppm BPA after 210 min, whereas the pure $TiO_2$ achieved no more than 50% decomposition under any conditions.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.39 no.9
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• pp.35-43
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• 2002

In this paper, microstrip ring with a narrow gap is characterized and used as a tunable microwave bandgap (MBG) structure. The center frequency of MBG is mainly determined by the mean circumference of the ring and coincides with odd mode resonance frequency of the ring resonator. The stop band formation by the proposed microstip MBG ring is due to the reflection of electromagnetic waves at the narrow gap introduced in the ring, and the reactive component mounted on the gap makes the stop band vary according to its value. The mounting of capacitor (inductor) is observed to decrease (increase) the center frequency of the stop band. The varactor-mounted microstrip MBG ring is expected to be useful in microwave switches and microwave amplifier circuits.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.11
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• pp.1414-1416
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• 2016

In this paper, a SWB (Super-WideBand) dipole antenna with self-complementary structure is proposed for signal intelligence. The proposed antenna consists of a self-complementary dipole antenna and a tapered balun for balanced feeding. The measured -10 dB reflection bandwidth of the proposed antenna is more than 28:1 (0.73-20 GHz) and 3 dB axial ratio bandwidth is 3.25:1 (1.91-6.22 GHz) with RHCP (Right Hand Circular Polarization) at +z direction. The measured radiation patterns are omni-directional in lower frequency band and bi-directional in higher frequency band. The measured peak gain within -10 dB reflection bandwidth varies from 2.83 dBi to 7.66 dBi.

• The Journal of the Korea institute of electronic communication sciences
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• v.12 no.4
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• pp.715-724
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• 2017

Today all kinds of smart devices are being developed with various researches on wearable devices that support smart computing on the human body. Skin diseases continue to rise including freckles, pimples, atopy, and scalp trouble due to the environmental and genetic factors, and people pay bigger medical bills to treat their skin diseases. There is thus a need to develop a smart-phone or table-based smart healthcare imaging system of high portability and diagnostic accuracy capable of analyzing and managing various skin problems related to skin care. This study proposed an integrated system combining the Smart Mi Band, a wearable device using moisture and UV sensors based on IoT, on the hardware part with the sensor information monitoring software.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.95-100
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• 2011

During the development of low band-gap organic materials(p-type semiconducting organic compounds) for organic solar cells, an oligomer consisting of 2,5-dioctyloxyphenylene(OP), 3-hexylthiophene(HT), and 2,3-dimethylthieno[ 3,4-b]pyrazine(TP) as repeat units, oligo(OP-HT-TP), was synthesized. The oligomer was amorphous in nature in the temperature range studied, and well soluble in common organic solvents such as chloroform. The maximum absorption wavelength was 716 nm in solid state. The band-gap and HOMO/LUMO energy levels of oligo(OP-HT-TP) were measured to be 1.20 eV and -5.27/4.04 eV, respectively. However, the absorbance of the oligomer at maximum absorption wavelength was less than one fifth of that of poly(3-hexylthiophene) which has been most frequently used in fabrication of organic solar cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.81-81
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• 2008

Applications of CdS films in this study are to exhibit a high conductivity when they are exposed at light with visible wavelength and sequentially to show a low conductivity in dark state. For this purpose, CdS films should have a high photosensitivity, still maintaining a high conductivity at a visible light. In this study, CdS films were prepared at room temperature on glass substrates by rf magnetron sputtering. In order to increase the photo-conductivity in visible light, various defect levels should be located within the CdS band gap. In order to nucleate the defect sites within the CdS band gap, CdS films were deposited on glass substrates at room temperature using various $H_2$/(Ar+$H_2$) flow ratios by an rf magnetron sputtering. Through the investigation of the structural and photoconductive properties of CdS films by an addition of hydrogen, the relationship between photo- and dark-resistance in CdS films was investigated in detail. 200-nm-thick CdS films for photoconductive sensor applications were prepared at various $H_2$/(Ar+$H_2$) flow ratios on glass substrates at room temperature by rf magnetron sputtering. Sulfur concentration in CdS films crystallized at room temperature with (002) preferred orientation depends directly on the hydrogen atmosphere and the surface roughness of the films gradually increases with increasing hydrogen atmosphere. Films deposited at 8% of $H_2$/(Ar+$H_2$) exhibit an abrupt decrease of dark- and photo-resistance, showing a low photo-sensitivity ($R_{dark}/R_{photo}$). Onthe other hand, films deposited at a hydrogen atmosphere of 42% exhibit a photo-sensitivity of $5\times10^3$, maintaining a photo-resistance of an approximately $2\times10^4\Omega$/square. The dark- and photo-resistance values of CdS films were related with a composition, surface roughness, and defect sites within the band gap.

• Plant Resources
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• v.2 no.1
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• pp.22-25
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• 1999

Molecular markers are useful to confirm the hybridity of F1 plant derived from cross of two homozygous parents with similar morphological traits. RAPD markers were used to test F1 hybrid plant obtained from cross of two homozygous soybean (Glycine max) parents. Fl plant for cross I was made from the mating of Hobbit87 (female) and L63-1889 (male) and Fl plant for cross II was obtained from the mating of H1053 (female) and L63-1889 (male). Selfing plant per each cross was also obtained. Among 20 Operon primers used, OPA04 and OPA09 show polymorphism between cross I and II parent. Band in size 1Kb of OPA04 and 2.1Kb of OPA09 primer was polymorphic band. This fragment identified Fl hybrid plant and selfing plant in cross I and II. Female parent Hobbit87 in cross I and H1053 in cross II has no this fragment (recessive allele). However, male parent L63-1889 and Fl hybrid plant in cross I and II has this size of polymorphic band (dominant allele). This indicated that Fl hybrid and selfing plants were detected by RAPD marker before phenotypic marker would be used to identify Fl hybridity. Amplification products of selfing plant for cross I and II were completely same to the those of female parent. When mature, flower color of Fl hybrid plant in cross I and II was purple and flower color of selfing plant in cross I and II was white. Purple flower is dominant trait. Fl hybridity was successfully detected at very early growth stage using RAPD marker. Therefore, RAPD marker can be used broadly to confirm Fl hybridity in many crops.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.11
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• pp.857-867
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• 2018

Active array radar is evolving into digital active array radar. Digital active array radar has many advantages for making several simultaneous radar beams from the digital receive data of each element. A digital-type transceiver(TR) module is suitable for this goal in radar. In this work, the design results of an L-band digital TR module are presented to verify the possibility of fabrication for a digital active array antenna. This L-band digital TR module consists of a gallium-nitride-type HPA to achieve a more than 350-W peak output power and one-chip transceivers that include a digital waveform generator and analog digital converter. The receiving gain was 47 dB, the noise figure was less than 2 dB, and the final output type of the four channel receiving paths was one optic signal.