• 정보과학회 논문지
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• 제45권3호
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• pp.288-293
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• 2018

최근 공개되는 데이터에 적용하는 다양한 프라이버시 보호 기법들이 연구가 되어왔다. 그 중 차분 프라이버시는 본래의 데이터에 확률적인 노이즈를 더하여 공격자의 사전 지식에 상관없이 개인 정보를 보호한다. 기존 차분 프라이버시를 만족하는 k-평균 클러스터링은 데이터로부터 차분 프라이버시를 만족하는 히스토그램 형태로 바꾼 뒤. k-평균 클러스터링 알고리즘을 수행한다. 하지만 이는 데이터의 분포와 상관없이 등간격으로 히스토그램을 만들기 때문에 노이즈가 삽입되는 버킷이 많아지는 단점이 있다. 이를 해결하기 위해 본 논문에서는 데이터의 분포를 더 적은 버킷으로 나타낼 수 있는 쿼드 트리를 이용하여 히스토그램을 만든 뒤 k-평균을 찾는 알고리즘을 제안한다. 또한, 실험을 통해 기존의 알고리즘보다 더 좋은 성능을 가지는 것을 보인다.

• 한국자동차공학회논문집
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• 제22권3호
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• pp.81-89
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• 2014

This study researched on the effect of HP/LP-EGR system to improve fuel consumption of Low Temperature Combustion Engine. Firstly, low temperature combustion engine with HP/LP-EGR system was established using 6.0L wastegate turbocharger HDDI engine. And suppliable EGR rate of the engine was proven to be enough to realize stable low temperature combustion. Then, optimum operating strategy was founded to develop fuel consumption of the engine. Control parameters were HP/LP-EGR valve and IPCV(Intake Pressure Control Valve) duty. Experiments method was that characteristics of the engine were measured and analyzed according to HP/LP-EGR strategies while EGR rate was fixed. Operating range for the strategy were divided into three parts, low load for low temperature combustion, high load for conventional diesel combustion, and transient condition. Finally, with the above strategy of this study, BSFC of the engine was improved about 2% compared to the base engine, and emission level, NOx and PM, met Tier4Final emission regulation.

• Progress in Superconductivity
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• 제9권2호
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• pp.167-172
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• 2008

We fabricated $YBa_2Cu_3O_{7-x}$(YBCO) films on (00l) $LaAlO_3$ substrates prepared by metal organic deposition(MOD) method using trifluoroacetate(TFA) solution. The films with various thicknesses were prepared by repeating the dip-coating and calcining processes. The effects of film thickness on phase formation, microstructures, and critical properties were evaluated by X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The microstructure and resultant critical current($I_C$) and critical current density($J_C$) varied remarkably with film thickness: The ($I_C$) value increased from 39 to 160 A/cm-width as the number of coatings increased from one to four, while the corresponding $J_C$ was measured to be in the range of $0.84-1.21\;MA/cm^2$. Both the $I_C$ and $J_C$ decreased when an additional coating was applied due to microstructural degradation, indicating that the optimum thickness is in the range of $1.1-1.8\;{\mu}m$. The possible cause for the decrease in the $I_C$ and $J_C$ value for film thicker than $1.8\;{\mu}m$ include non-uniform thickness, increased surface roughness, and the poor formability of the YBCO phase and texture arising from the insufficient heat treatment time with respect to the increased thickness.

• 한국균학회지
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• 제16권3호
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• pp.162-174
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• 1988

구름버섯 배양균사체와 야생 구름버섯 자실체로부터 얻은 protein-bound polysaccharide의 당과 단백질 함량을 비교하였을 때 배양균사체인 경우보다 야생 자실체의 경우가 당 함량이 더 높게 나타났으며 단백질 함량은 더 적게 나타났다. 구름버섯에서 부터 얻은 시료를 methanolysis시킨 후 HPLC로 분석하였을 때 배양균사체인 경우 4종류의 단당이 경출되었고 그중 mannose가 가장 함량이 많은 반면 야생 자실체인 경우 3종류의 단당이 경출되었으며 그중 glucose가 가장 많이 존재하였다. 구름버섯에서부터 얻은 시료에 lactose가 혼합되었을 경우 HPLC로 구별할 수 있었다. 구름버섯에서 얻은 시료의 구성 아미노산을 분석하였을 때 시료 모두에서동일한 17종의 아미노산이 검출되었다.

• Food Science and Biotechnology
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• 제18권1호
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• pp.108-112
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• 2009

Antioxidant and anticancer effects of methanolic extracts from the flesh (WFME) and peel (WPME) of white onion, the flesh (YFME) and peel (YPME) of yellow onion, the flesh (RFME) and peel (RPME) of red onion were studied. The content of total phenolics in WFME, WPME, YPME, YFME, RPME, and RFME were $0.260{\pm}0.01$, $4.480{\pm}0.23$, $0.319{\pm}0.02$, $719.12{\pm}37.36$, $0.248{\pm}0.01$, and $806.21{\pm}26.38\;mg/g$, respectively. The quercetin content of WFME, WPME, YFME, YPME, RFME, and RPME were $12.56{\pm}0.19$, $3.57{\pm}0.14$, $15.24{\pm}0.65$, $755.29{\pm}22.24$, $5.70{\pm}0.23$, and $774.03{\pm}29.48\;mg$/100 g, respectively. Like total phenolics, the highest 2,2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities were found in RPME. However, inhibitory effects on lipid oxidation of RPME were similar to those of WPME and YPME. In addition, inhibitory effect of WPME, YPME, and RPME for human breast cancer cell (MCF-7) growth were 78.43, 81.90, and 96.52% while those on human prostate cancer cell (LNcap) were 71.58, 77.93, and 98.47% at $100{\mu}g/mL$, respectively. Total phenolics, quercetin content, antioxidant, and anticancer activities exhibited significant variation among the 3 onion varieties in this experiment. Therefore, it is assumed that antioxidant and anticancer activities were affected by the total phenolics and quercetin level of onion.

• 대한한의학회지
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• 제19권2호
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• pp.59-74
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• 1998

Clinical observation was done on 272 cases of patients who were diagnosed as CVA with brain CT, TCD, MRI scan and clinical observation. They were hospitalized in the oriental medical hospital of Kyung-Won University from 1st January to 31st December in 1997. 1. The cases were classified into the following kinds: cerebral infarction, cerebral hemorrhage. and transient ischemic attack. The most case of them was the cerebral infarction. 2. There is no significant difference in the frequency of strokes in male and female. And the frequency of strokes was highest in the aged over 50. 3. In cerebral infarction the most frequent lesion was the territory of middle cerebral artery, and in cerebral hemorrhage the most frequent lesion was the basal ganglia. 4. The most ordinary preceding disease was hypertension. and the next was diabetes. 5. The rate of recurrence was high in cerebral infarction. 6. The cerebral infarction occurred usually in resting and sleeping, and the cerebral hemorrhage in acting. 7. The common symptoms were motor disability and verbal disturbance. 8 The average time to start physical therapy was 1l.3rd day after stroke in cerebral infarction and it was 15.2th day after stroke in cerebral hemorrhage. 9. The common complications were urinary tract infection, pneumonia, myocardial infarction. 10. Hypercholesterolemia and hypertriglyceridemia are usually found more frequently in cerebral infarction than in hemorrhage. 11. In acute or subacute stage, the methods of smoothening the flow of ki(順氣), dispelling phlegm(祛痰), clearing away heat(淸熱) or purgation(瀉下) were frequently used. and in recovering stage, the methods of replenishing ki(補氣), tonifying the blood(補血) or tranquilization(安神) were frequently used.

• 한국미생물·생명공학회지
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• 제35권3호
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• pp.191-195
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• 2007

탄닌 분해균 선발배지를 이용하여 탄닌 분해활성 보유 유산균을 발효 침채류로부터 분리하는 과정에서 오이소박이, 파김치, 총각김치로부터 다당류로 추정되는 점질물질을 생산하는 균주 4종을 선발하였다. 이들 균주의 165 rDNA 염기서열에 의한 계통유전학적 동정 결과, CK31은 Enterobacter cowanii, CK32는 Escherichia senegalensis, YK5는 Enterobacter asburiae, GK23은 Enterobacter ludwigii와 99% 이상의 매우 높은 상동성을 나타내었다. 가장 많은 양의 점질 물질을 세포 외로 생성하는 CK3l 균주는 rhamnose, fucose, arabinose, mannose, galactose, glucose의 중성당 조성을 가지고 있는 분자량 약 420 kDa heteropolysaccharide를 생산하는 것으로 나타났다.

• Journal of Microbiology and Biotechnology
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• 제24권11호
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• pp.1559-1565
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• 2014

Cellulase and xylanase are main hydrolysis enzymes for the degradation of cellulosic and hemicellulosic biomass, respectively. In this study, our aim was to develop and test the efficacy of a rapid, high-throughput method to screen hydrolytic-enzyme-producing microbes. To accomplish this, we modified the 3,5-dinitrosalicylic acid (DNS) method for microwell plate-based screening. Targeted microbial samples were initially cultured on agar plates with both cellulose and xylan as substrates. Then, isolated colonies were subcultured in broth media containing yeast extract and either cellulose or xylan. The supernatants of the culture broth were tested with our modified DNS screening method in a 96-microwell plate, with a $200{\mu}l$ total reaction volume. In addition, the stability and reliability of glucose and xylose standards, which were used to determine the enzymatic activity, were studied at $100^{\circ}C$ for different time intervals in a dry oven. It was concluded that the minimum incubation time required for stable color development of the standard solution is 20 min. With this technique, we successfully screened 21 and 31 cellulase- and xylanase-producing strains, respectively, in a single experimental trial. Among the identified strains, 19 showed both cellulose and xylan hydrolyzing activities. These microbes can be applied to bioethanol production from cellulosic and hemicellulosic biomass.

• Bulletin of the Korean Chemical Society
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• 제31권6호
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• pp.1583-1588
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• 2010

A single step fabrication process of carbon nanotube/Prussian Blue (CNT/PB) paste electrodes based on screen printing technology has been studied as an amperometric sensor for the determination of hydrogen peroxide and free chlorine. Compared to the classical carbon paste (CP) electrode, the CNT paste electrode greatly enhanced the response in the presence of hydrogen peroxide due to the electrocatalytic activity of the CNT. Based on the CNT/binder paste, PB was also incorporated into a network of CNT paste and characterized. The best electroanalytical properties of PB-mixed sensors to hydrogen peroxide were obtained with PB ratio of 10 wt % composition, which showed fast response time ($t_{90}{\leq}5$ s; 0.2 - 0.3 mM), low detection limit of 1.0 ${\mu}M$, good linear response in the range from $5.0{\times}10^{-5}$ - $1.0{\times}10^{-3}$ mol $L^{-1}$ ($r^2$ = 0.9998), and high sensitivity of -8.21 ${\mu}AmM^{-1}$. In order to confirm the enhanced electrochemical properties of CNT/PB electrode, the sensor was further applied for the determination of chlorine in water, which exhibited a linear response behavior in the range of 50 - 2000 ppb for chlorine with a slope of 1.10 ${\mu}Appm^{-1}$ ($r^2$ = 9971).

• Bulletin of the Korean Chemical Society
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• 제34권8호
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• pp.2394-2398
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• 2013

Nicotine is the main component of environmental tobacco smoke, and its presence in indoor air is widely used as a secondhand-smoke indicator. Environmental tobacco smoke is a major source of indoor air pollution, but sufficient investigation of the uncertainty of its measurement, which mirrors the reliability of nicotine measurement, has not been performed. We calculated the uncertainty of measurement of indoor air nicotine concentration at low, medium, and high concentrations of 11.3798, 10.1977, $98.3768{\mu}g/m^3$, respectively, and we employed the Guide to the Expression of Uncertainty in Measurements (GUM), proposed by the International Organization for Standardization (ISO). The factors considered in determining the uncertainty were uncertainty of the calibration curve (calibration curve and repeated measurements), desorption efficiency, extraction volume, and sampling airflow (accuracy and acceptable limits of flowmeter). The measurement uncertainty was highest at low concentrations; the expanded measurement uncertainty is $0.9435{\mu}g/m^3$ and is represented as a relative uncertainty of 63.38%. At medium and high (concentrations, the relative uncertainty was 13.1% and 9.1%, respectively. The uncertainty of the calibration curve was largest for low indoor nicotine concentrations. To increase reliability of measurement in assessing the effect of secondhand smoke, measures such as increasing the sample injection rate ($1{\mu}L$ or more), increasing sampling volume to increase collected nicotine, and using gas chromatography-mass spectrometry (GC/MS) or GC/MS/MS, which has a lower quantitation threshold, rather than gas chromatography with nitrogen phosphorous detector, should be considered.