• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.324-324
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• 2020

기후변화에 따른 기상 요소별 추세 변화는 유역유출량의 변동성을 증가시켜 안정적인 수자원 확보 및 홍수 대비에 어려움을 줄 수 있다. 따라서 기후변화에 따른 유역 유출량 변화를 평가하기 위한 많은 연구가 이루어져 왔다. 기존에는 기후변화 자료의 공간적 해상도의 한계로 인해 중대유역을 중심으로 연구가 다수 이루어져 왔으나, 최근 들어, 기후변화 자료의 공간적 상세화 기법이 발달함에 따라 소유역별 유역 유출량 평가에 관한 연구가 증가하고 있다. 특히, 소유역의 경우 유역 특성에 따라 기후변화에 따른 유출량 변화 민감도가 높을 수 있으며, 유출 성분별 변화가 상이할 수 있다. 하지만 기존의 연구에서는 소유역을 대상으로 기후변화에 따른 유출 성분별, 예를 들어 직접유출량과 기저유출량을 구분하여 변화를 평가하는 연구가 부족한 실정이다. 따라서 본 연구에서는 기후변화에 따른 소유역의 유출 성분별 특성을 분석하기 위하여, RCP 4.5, 8.5 시나리오별 기후모델 10개에 대하여 모의한 유출량을 직접유출량과 기저유출량으로 구분하고 결과를 비교 분석하였다. 본 연구의 대상지역은 유역면적이 112.9 ㎢이며, 토지이용이 단순하고, 농경지의 비율(약 50%)이 높은 농업 소유역을 대상으로 하였다. 유출량을 모의하기 위한 모형으로는 농업 소유역 유출량 모의 연구에 다수 사용된 바 있는 SWAT 모형을 이용하였으며, 직접유출량과 기저유출량의 분리는 Recursive Digital Filter 방법을 이용하였다. 기후변화 자료는 기후모델의 연산능력의 한계나 복잡한 자연조건의 불완전한 반영 등의 이유로 지역 기후변화 예측 과정에서 발생하는 불확실성을 지니고 있으므로 RCP 4.5, 8.5 시나리오별 각각 10개 기후모델의 결과를 이용하여 유출 특성 분석에 활용하였다. 본 연구의 결과는 향후 소유역의 미래 유량특성을 파악하기 위한 기초 자료로 활용될 수 있을 것으로 사료된다.

• Korean Journal of Food Science and Technology
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• v.51 no.6
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• pp.543-550
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• 2019

In this study, volatile compounds in 13 aged and 3 commercial rice-distilled soju samples were isolated by headspace solid phase microextraction (HS-SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 85 volatile components including 35 esters, 15 alcohols, 5 ketones, 3 aldehydes, 15 miscellaneous, and 14 unknowns were identified. Esters and alcohols were the largest groups among the quantified volatiles. Differences in volatile compounds among the distilled soju samples and possible sample groupings were examined by principal component analysis of the GC-MS datasets. The first and second principal components (PC1 and PC2, respectively) explained 51.94% of the total variation across the 16 samples. The samples aged in oak containers had higher concentrations of ketones, aldehydes, and miscellaneous compounds. In the positive direction of PC1, oak-aged samples were observed, while, pot-aged samples were observed on the far negative side. Furthermore, samples aged for longer periods, such as 18 months, were observed in the positive direction of PC2.

• Korean Journal of Food Science and Technology
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• v.49 no.1
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• pp.14-19
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• 2017

The objective of this study was to analyze the volatile changes occurring in retort pouches during heating using a mass spectrometry-based electronic nose. The data obtained by the electronic nose analysis was used to generate a discriminant function analysis plot. The plot showed that volatile compounds of the heated water in the retort pouch were increased by the interaction between container and water as the heating time increased. Conversely, volatile compounds of the container itself decreased when only the container was measured separately. This result means that volatile compounds from the packaging material migrated into the water. In the case of heated beef bone soup, volatile compounds were increased compared to the unheated beef bone soup after 20 min of heating. According to the results of GC/MS, nonanal and 3,5-di-tert-butyl-4-hydroxytoluene (BHT) were detected in the heated water and nonanal, heptanal, octanal, and BHT were detected in the heated beef bone soup.

• Korean journal of food and cookery science
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• v.3 no.1
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• pp.64-70
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• 1987

The effects of salting on the compositional and textural changes of Korean cabbage were studied. The optimum brining conditions were established ana the dietary fiber composition, mineral contents and moisture content of raw and salted Korean cabbage were determined. The cutting test of cabbage was made by Rheometer and the brittleness and chewiness were evaluated organoleptically. The optimum condition for brining was at 20% NaCl concentration for 6 hours. In the compositional changes of Korean cabbage by salting at 20% NaCl solution for one month, the content of hot water soluble pectin (HW-P) increased from 43.6% to 55.9% and that of hexametaphosphate soluble pectin (HM-P) decreased from 35.9% to 29.5%. The contents of cellulose and hemicellulose increased, but that of lignin decreased slightly by salting, showing no significant differences in raw and salted cabbage. The content of Na increased significantly and those of Ca, Mg and K decreased by salting. And also moisture content decreased from 91% to 79%. In the textural changes of Korean cabbage by salting, the maximum cutting force and cutting work increased five times and two and half times respectively. And organoleptic test did show significant increase in chewiness and decrease in brittleness. The maximum cutting force by Rheometer was well correlated with the sensory parameters. The results taken together showed that the changes in textural properties during salting are relevant to the changes in pectic substances, moisture content and mineral contents, but relatively irrelevant to the changes in cellulose, hemi-cellulose ana lignin. And it is considered that the maximum cutting force by cutting test is good means for the expression of texture of Korean cabbage.

• Journal of the Korean earth science society
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• v.38 no.4
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• pp.263-268
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• 2017

The determination algorithm of the location of a line source with strike and dip using the gravity gradient tensor on a single profile is proposed. We already proposed the determination of strike and dip in the previous paper and then, now we improved the algorithm to locate a line source after determining strike and dip. The strike and dip of the line source can be determined by rotating the gravity gradient tensor matrix as reducing 2 independent components. Using the ratio of remaining 2 components, the location can be determined by the least square manner of the pointing vectors on each observation point. A synthetic model is tested for proving the usefulness of the proposed algorithm.

• Korean Journal of Food Science and Technology
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• v.28 no.4
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• pp.772-778
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• 1996

In order to investigate changes of flavor during food sterilization in retortable pluches, a model food system consisting of 50% chicken breast meat, 1% salt and 49% chicken stock was analyzed before and after retorting using GC and GC-MS. In the analysis of the volatile components collected by the nitrogen purge and trap technique before and after retorting, a total of 53 peaks were observed on chromatograms and 42 peaks were identified. Among the 42 peaks identified were 17 caused by aldehydes, 9 by hydrocarbons, 8 by alcohols, 6 by ketones, 1 by furan and 1 by terpene. Analysis of the data obtained from our model food system strongly suggested that the compounds responsible for retort flavor are 2-heptanone, 2-pentyl furan and various ketones.

• Applied Biological Chemistry
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• v.40 no.6
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• pp.472-477
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• 1997

The effects of roasting Cassia tora L. were investigated for proximate composition, color, volatile flavor profile, microbial growth and alcohol fermentation. While moisture, protein and fat contents decreased with increasing roasting temperature, fiber and ash contents increased. The L, a and b values of Cassia tora L. extracts decreased with increasing temperature, and only a small difference in total color difference$({\Delta}E)$ was observed. A little difference in major flavor components between raw and roasted treatment was found during roasting. Furfuryl alcohol, a major component of coffee flavor, was separated from Cassia tora L. extracts extracted with ethyl ether. The yeast growth was the highest on the water-extract of Cassia tora L. roasted at $160^{\circ}C$. With increased levels of water-extract at $160^{\circ}C$, S. cerevisiae grew rapidly for 24 hr incubation and the growth rate was higher than the unroasted control group. The growth rate of Bacillus subtilis was the highest in a treatment of 0.5% concentration. Little differences in ${\alpha}-amylase$ produced from Bacillus subtilis were observed among the treatment groups. The total alcohol content increased with increasing roasting temperature during alcohol fermentation.

• KSBB Journal
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• v.22 no.5
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• pp.336-340
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• 2007

Supercritical carbon dioxide was used to remove coffee odors. The odor removal efficiency was tested with coffee drink prepared by the espresso extraction method. Five typical odors in coffee were analyzed with GC and these odors in deodorized coffee were compared to those in control. Supercritical carbon dioxide extraction conditions were optimized as 350 bar and 70$^{\circ}C$ because the solvating power of supercritical fluid is depend on the density which is determined by temperature and pressure. A modified head space method was applied to collect coffee odors in coffee drink prepared by the espresso extraction method. Odors generated in coffee drink made with deodorized coffee powder were reduced by 73% in total mass of typical five coffee odors.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.2
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• pp.146-146
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• 1995

본 논문은 유도전동기의 운전조작시에 발생되는 자계변화특성에 대하여 기술하였다. 본 측정시스템은 자기적분형 자계센서, 증폭기, 능동형 적분기로 이루어졌으며, 교정실험에 대한 측정계의 주파수대역과 감도는 각각 20[Hz]∼0.234[mV/μT]이다. 유도전동기의 기동과 정상운전중에 발생하는 자계성분을 측정하였으며, 고조파 성분을 고속 푸리에 변환기법으로 분석하였다. 유도전동기의 직입기동시에는 단일성 펄스자계가 강하게 발생하였으며, 이의 피크치는 정상상태의 값보다 5배이상 크게 나타났다. 이러한 긴 과도시간과 강한 자계의 세기는 전동기의 큰 인덕턴스와 동특성에 기인된다. 유도전동기의 정상운전시에는 유도전동기의 극수에 의존하는 기본파에 대한 분조파의 자계성분이 관측되었다. 또한, 자계의 분조파 성분은 전동기의 토크 변동으로 불균일한 회전토크로 인해 생기는 맥동전류와 전압플리커에 의해서 발생하는 것으로 생각된다. 인버터구동형 유도전동기에서는 직입기동에 비하여 많은 고조파 성분이 발생되고 있었으며, 특히 전동기의 구동주파수가 낮을수록 맥동토크에 의한 전류변화로 고조파 성분은 더욱 증가하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2016.06a
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• pp.99-102
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• 2016

교통표지판 검출 및 인식은 차량의 자율주행 및 ADAS (Advanced Driver Assistance System)의 필수적인 요소이다. 교통표지판의 각종 표식을 인식하기 위해서는 먼저 교통표지판 영역을 검출해야 하며, 이 작업은 통상적으로 교통표지판에 포함된 빨간색을 추출하는 컬러 필터링을 통해 이루어진다. 하지만 차량 영상에 나타나는 색상 성분은 태양광의 방향이나 날씨 등에 상당한 영향을 받으며 이러한 조도 환경은 차량이 주행하게 되면 시간적으로도 수시로 변화한다. 더군다나 사용하는 카메라의 내부적인 특성에 따라서도 색상 성분의 분포가 달라지기 때문에 컬러 필터링을 위한 임계값은 고정값을 사용하기 보다는 적응적으로 변화시킬 필요가 있다. 본 논문에서는 다양한 조도 환경과 다양한 카메라 종류에 따라서 영상 내 교통표지판의 빨간색 성분의 분포를 분석하고 이를 바탕으로 임계값을 가변적으로 설정하는 방법을 제안한다. 그리고 모의실험을 통해 제안 방법을 적용하면 고정된 임계값을 사용한 방법보다 조도변화에 강인하게 교통표지판 영역을 검출할 수 있음을 확인하였다.