• Journal of Environmental Impact Assessment
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• v.13 no.6
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• pp.277-284
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• 2004

The chemical composition and properties of soil were determined at selected sites, such as Loess plateau, Gobi and sand deserts in northern China, where most dust storms occur. Although the transport of this sort of dust storms to Korean peninsula is a well-documented phenomenon, there is not enough information about the very source regions. In this reason, this study tried to measure the chemical composition, including soil elements, anthropogenic elements and ions for soil samples so that certain properties of some major source regions of Asian Dust can be provided. Furthermore, the results are classified into four types of soil like Loess, Loess & sand, Gobi, and sand in order to identify the characteristics and difference among the types. $(X/Al)_{crust}$ values for each soil type were also calculated in this study and compared with those of other references including Asian Dust material(ADM). The results indicated that Ca contribution was higher than Al in all the soil types of this study including ADM and, compared with the values of urban area, contribution of anthropogenic elements such as Cr, Pb, Zn was quite low. However, it must be noted that there is such a variation in the result of soil composition, but it is also certain that the very source region soil composition resolved from this study could support the enhanced study on Asian Dust phenomenon in Korea.

• Journal of Environmental Impact Assessment
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• v.16 no.5
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• pp.351-361
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• 2007

To evaluate dominant synoptic classes which affect on $PM_{10}$ concentration in Seoul, 64 synoptic classes are classified from four seasons, 850hPa geopotential wind and lower level stability Index. In this study, we used air monitoring and meteorological data in Seoul for five years from 2001 to 2005. The results indicate that the highest occurrence frequency of synoptic class is under a strong westerly geopotential wind and stable lower atmosphere in spring. The highest $PM_{10}$ concentration of synoptic class is associated with a weak geopotential wind speed and high lower level stability. In that class, not only $PM_{10}$ but $SO_2$, $NO_2$ and CO concentrations are also higher than other classes. The analysis of spacial distribution of $PM_{10}$ concentration in each class are indicate that the influence of synoptic class are similar in the Metropolitan area in Korea. But $PM_{10}$ concentration in some areas in Kyoung-Gi are more higher than in Seoul. The relationship between $PM_{10}$ concentration and Meteorological indicator (relative humidity, temperature, surface wind speed) under same synoptic class is more correlative in Winter than other season.

• Korean Journal of Psychosomatic Medicine
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• v.5 no.1
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• pp.118-122
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• 1997

We experienced a case of 51-year-old female patient who showed symptoms of persecutory delusion, auditory hallucination and hallucinatory behavior, severe insomnia, psychomotor retardation and social withdrawal, along with some clinical signs of the deficiency of various hormones those gradually progressed after massive postpartum vaginal bleeding 13 years ago. She was admitted to a psychiatric ward under the impression of psychotic depression. However careful history taking and evaluation of clinical feature gave rise to the possibility of underlying medical condition. Laboratory work-up revealed panhypopituitarism, hypoglycemia and hyponatremia. After replacement of thyroid hormone and cortisol for 1 week, her clinical symptoms including psychiatric symptoms were improved. Taken together, these findings were compatible with the diagnosis of Sheehan's syndrome. On reporting this case, we would like to emphasize again the importance of differential diagnosis of medical problems causing psychiatric symptoms those are easily neglected in the clinical approach toward psychiatric patients.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.206-206
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• 2003

피클(pickles)은 구미 각국에서 널리 애용되는 침채류이다. 수확한 농산물의 신선도를 유지하면서 장기보관 하기 위해 만들어진 것으로 여러 가지 방법이 시도되어 왔고, 동양에서는 높은 습도로 인한 곰팡이 증식을 억제하기 위하여 소금 절임 방법이 발달되었으며, 건조한 기후의 유럽에서는 세균번식을 억제하기 위하여 식초절임이 발달하였다. 피클이란 채소 또는 과실류를 소금, 식초 또는 여기에 향신료 등을 넣은 것에 절인 것을 총칭하는 것으로, 주로 오이, 컬리플라워, 양파, 미숙 토마토 등을 원료로 사용한다. 본 연구에서는 피클의 특징인 아삭아삭함을 유지하면서, 피클의 신맛과 한국 전통식장아찌를 혼용한 염장피클로, 기능적 특성을 가진 허브를 첨가하여 현대인에게 오는 성인병의 예방과 기능성 식품에 부가 가치를 높이고자 하며, 또한 피클 제조를 위한 고추의 품종 선정을 위한 기초 실험을 하고자 함에 있다. 풋고추, 청양고추, 꽈리고추 등 품종을 달리하여 제조한 고추피클의 숙성기간 중 품질특성을 실험하였다. 염도변화는 모든 품종에서 숙성기간이 길어질수록 염도가 낮아졌으며, 숙성이 완료되는 시점인 25일경에는 풋고추 2.95%, 청양고추 2.68%의 염도 변화를 보였다. pH변화는 세 품종간에 차이는 없는 것으로 보여졌으며, 숙성기간에 따른 차이도 거의 없는 것으로 나타났다. 고형분함량은 풋고추와 꽈리고추가 비슷한 경향을 보였고, 청양고추가 다소 높았다. 적정산도의 변화는 세 품종간에 차이는 없었지만, 숙성이 진행될수록 증가하는 경향을 보였다. 탁도변화는 꽈리고추가 가장 낮았고, 청양고추가 가장 높았으며, 숙성이 진행될수록 모두 탁해지는 경향을 보였다. 또한 피클의 경도변화는 풋고추는 0일에 45.12g 청양고추는 56.68g, 꽈리 고추 42.12g의 경도를 보였으며, 숙성최종단계인 25일에는 풋고추 20.33g, 청양고추 25.12g, 꽈리고추는 17.81g으로 꽈리고추의 경도가 가장 낮았고, 청양고추는 세 품종 중에서 가장 높은 것으로 나타났으며, 세 품종 모두 숙성이 진행될수록 경도가 현저히 낮아지는 것으로 나타났다.

• Journal of the Korean Geotechnical Society
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• v.37 no.12
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• pp.89-105
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• 2021

In this paper, feasibility study was carried out to evaluate necessity of seismic design of earth retaining structures in a deep excavation. Dynamic behavior of retaining system was analyzed using FLAC, a finite difference analysis program. It was shown that maximum bending moments of retaining walls and axial forces of supports were increased up to 98% and 87% during earthquake, respectively, compared to final excavation step, which indicates that dynamic earth pressure has a large effect on a retaining system. The stability of retaining system designed according to current design specifications was evaluated using structural forces obtained by numerical analysis, and effect of earthquake loading on structural design was analyzed.

• Food Engineering Progress
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• v.15 no.3
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• pp.214-220
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• 2011

$\beta$-Glucosidase enzyme reaction under high hydrostatic pressure was investigated in terms of physical chemistry. A model substrate (p-nitrophenyl-${\beta}$-D-glucopyranoside(pNPG)) was used, and the pressure effects on the enzymatic hydrolysis (pNPG${\rightarrow}$pNP) at 25 MPa, 50 MPa, 75 MPa, and 100 MPa were analyzed. Two parts of the reaction such as kinetic and equilibrium stages were considered for mathematical modelling, and their physicochemical parameters such as forward and inverse reaction constants, equilibrium constant, volume change by pressure, etc. were mathematically modeled. The product concentration increased with pressure, and the two stages of reaction were observed. Prediction models were derived to numerically compute the product concentrations according to reaction time over kinetic to equilibrium stages under high pressure condition. Conclusively, the $\beta$-Glucosidase enzyme reaction could be activated by pressurization within 100 MPa, and the developed models were very successful in their prediction.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.4
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• pp.183-190
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• 2018

Predicting accurate electricity prices is an important task in the electricity trading market. To address the electricity price forecasting problem, various approaches have been proposed so far and it is known that linear regression-based approaches are the best. However, the use of such linear regression-based methods is limited due to low accuracy and performance. In traditional linear regression methods, it is not practical to find a nonlinear regression model that explains the training data well. If the training data is complex (i.e., small-sized individual data and large-sized features), it is difficult to find the polynomial function with n terms as the model that fits to the training data. On the other hand, as a linear regression model approximating a nonlinear regression model is used, the accuracy of the model drops considerably because it does not accurately reflect the characteristics of the training data. To cope with this problem, we propose a new electricity price forecasting method that divides the entire dataset to multiple split datasets and find the best linear regression models, each of which is the optimal model in each dataset. Meanwhile, to improve the performance of the proposed method, we modify the proposed localized linear regression method in the map and reduce way that is a framework for parallel processing data stored in a Hadoop distributed file system. Our experimental results show that the proposed model outperforms the existing linear regression model. Specifically, the accuracy of the proposed method is improved by 45% and the performance is faster 5 times than the existing linear regression-based model.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.6
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• pp.492-498
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• 2021

This study examined how the emissions of pollutants affect the volume of traffic of freight vehicles in the transport sector. Multiple regression analysis was conducted considering several variables, including population by region, area of urban district, GDP, and the number of businesses by industry, e.g., agriculture, forestry, fishery, manufacturing, wholesale, and retail. These variables differ according to the characteristics of the freight vehicles (industry, by the ton). Therefore, it is essential to fully consider the volume of traffic of the specific freight vehicles by region before implementing relevant programs and policies, such as specific restrictions on the operation of vehicles. Some specific areas, in which logistic centers are located have heavy freight traffic, and these centers deserve extra consideration. Thus, in this study, different regional factors that affect the traffic of freight vehicles should be considered before determining the areas that will be subject to restrictions on the operation of these vehicles.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.50 no.2
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• pp.83-92
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• 2022

This paper analyzes the performance of the IRA(Interferometric Radar Altimeter) by terrain type for estimating reliability of TRN(Terrain Referenced Navigation). The accuracy of the altitude is one of the key parameters of TRN's accuracy. When the antenna of the IRA has wide beamwidth, its altitude accuracy is directly affected by the configuration of the earth's surface. Hence, the accuracy and reliability of TRN can also be affected and may cause ambiguity in positioning. We present analysis data for estimating the reliability of TRN by modeling several topographies and analyzing the performance of the IRA. The results of the analysis are verified by comparison with test data.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.482-482
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• 2023

상수도관은 사용년수가 경과함에 따라 노후화가 진행되며, 노후화된 상수관은 내부적으로 부식, 이물질 퇴적, 균열 등의 현상이 발생하게 되고, 이는 결국 수질문제로 연결되어, 탁수사고 발생 확률증가의 주요 원인이 되고 있다. 국내 상수도관의 경우 매설년수의 증가로 인해 내구연한이 도래한 상수관망의 비중이 점차 증가하고 있으며, 2019년 서울시 문래동 수질사고, 2019년 인천 붉은 수돗물 사고, 2022년 안양 동안구 탁수사고, 2022년 여수시 웅천 탁수사고 등 관의 노후화로인한 탁수 사고가 빈번하게 발생되고 있어 수도 사용자에게 불편함을 끼치고 있다. 현재 정수장 및 상수관망에 설치된 탁도계를 통해 수질에 대한 감시를 진행하고 있지만, 경제적인 문제로 인해 모든 상수도관에 탁도계를 설치하기에는 현실적으로 불가능하며, 제한적인 탁도계의 개수를 통해 수질에 대한 감시 및 관리를 진행하고 있는 실정이다. 이러한 상황으로 인해 탁수사고 발생 시 발생 원인분석 및 최초 발생위치 결정이 쉽지 않으며, 보수 보강을 통한 상수도관의 정상화까지 오랜 시간이 걸리게 된다. 이에 본 연구에서는 상수관망에서 탁수 발생 시 최초 발생 위치를 결정할 수 있는 기법을 개발하였으며, 이를 실제 상수도관망에 적용하여 탁수발생 파이프를 탐지하였다. 탁수사고 발생 시 실측된 수질 데이터의 부족으로 인해 임의의 파이프에서 탁수가 발생하였다고 가상의 탁수 발생시나리오를 가정하였으며, 완전혼합농도식을 통해 관망에 설치된 탁도계의 NTU(Nethelometric Paultity Unit) 농도를 계산하여 가상의 탁수발생 시나리오를 상수도관망에 적용하였다. 이후, 역추적 계산기법을 통해 파이프의 초기 NTU 농도를 변화시켜주며 관망내 설치된 탁도계의 NTU 농도를 계산하였으며, 가상 시나리오를 적용하여 계산된 탁도계의 NTU 농도와 역추적 계산법을 적용하여 계산된 탁도계의 NTU 농도의 Percentage Error를 비교/분석하여 탁수 발생 파이프를 탐지하였다. 분석결과, 가상 시나리오의 최초 탁수발생 파이프와 역추적 계산법을 적용하여 탐지한 최초 탁수발생 파이프의 위치가 일치하는 것으로 나타났다. 본 연구에서 개발된 역추적계산을 통한 탁수발생 파이프 탐지기법을 실제 관로 교체사업에 활용한다면 파이프의 개선 우선순위를 보다 명확하게 판단할 수 있으며, 더 나아가 상수도 관망의 유지관리에 활용하여 경제적이고 효율적인 상수관망 시스템관리를 할 수 있을 것으로 판단된다.