• Analytical Science and Technology
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• v.22 no.5
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• pp.376-385
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• 2009

In our study, the accuracy for measurement of seventeen 2,3,7,8-substituted PCDDs/PCDFs in certified reference material (CRM) which is the sample of homogeneous sediment matrix taken from an area known to have significant chemical contamination, particularly PCBs (polychlorinated biphenyls), was evaluated. Though the methodology in this study followed the official method of unintentionally produced persistent organic pollutants (UPOPs) announced by the Ministry of Environment of the Republic of Korea in 2007, there were slight changes using additional purification step by activated carbon column because the interferences of sample were not sufficiently removed when only multi-silica column and alumina column have been used for purification. The |En| number proposed by the Korea Research Institute of Standards and Science was used for a valuation basis of the accuracy. The |En| numbers of seventeen 2,3,7,8-substituted PCDDs/PCDFs have been indicated as 1 and below, they were decided "Pass" in this test, when DB-5MS column and SP-2331 column were used together. Because 1,2,3,7,8-PeCDD and #169-HxCB were not separated on DB-5MS column, the ions of 1,2,3,7,8-PeCDD were selected at M/M+2 instead of M+2/M+4 suggested by EPA 1613. It is possible to distinguish them in HRGC/HRMS analysis.

• Analytical Science and Technology
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• v.21 no.6
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• pp.518-525
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• 2008

Mandipropamid is a new mandelamide-type fungicide to control foliar Oomycete pathogens in some vegetables. An analytical method was developed to determine mandipropamid residues in agricultural commodities using high-performance liquid chromatography (HPLC) and liquid chromatography/mass spectrometry (LC/MS). Mandipropamid was extracted with methanol from grape, tomato, green pepper, Chinese cabbage and potato samples. The extract was diluted with saturated sodium chloride solution and distilled water, and dichloromethane partition was followed to recover the mandipropamid from the aqueous phase. Florisil column chromatography was employed to further remove interfering co-extractives prior to HPLC analysis. Reverse-phased HPLC was successfully applied to determine mandipropamid in sample extracts with the detection at its ${\lambda}_{max}$ (223 nm). Overall recoveries of mandipropamid from fortified samples averaged $99.8{\pm}1.7$ (n=6), $89.3{\pm}5.3$ (n=6), $98.7{\pm}2.2$ (n=6), $99.7{\pm}6.8$ (n=6) and $91.1{\pm}3.1$ (n=6) for grape, tomato, green pepper, Chinese cabbage and potato, respectively. Limit of quantification of the method was 0.02~0.04 mg/kg for all samples. A LC/mass spectrometry with selected-ion monitoring was also provided to confirm the suspected residue. The proposed method was reproducible and sensitive enough to determine the terminal residue of mandipropamid in agricultural commodities.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.2B
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• pp.199-213
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• 2008

The goal of this research is to develop and apply the integrational operation method (IOM) for the modeling of the monthly pan evaporation (PE) and the alfalfa reference evapotranspiration ($ET_r$). Since the observed data of the alfalfa $ET_r$ using lysimeter have not been measured for a long time in Republic of Korea, Penman-Monteith (PM) method is used to estimate the observed alfalfa $ET_r$. The IOM consists of the application of the stochastic and neural networks models, respectively. The stochastic model is applied to generate the training dataset for the monthly PE and the alfalfa $ET_r$, and the neural networks models are applied to calculate the observed test dataset reasonably. Among the considered six training patterns, 1,000/PARMA(1,1)/GRNNM-GA training pattern can evaluate the suggested climatic variables very well and also construct the reliable data for the monthly PE and the alfalfa $ET_r$. Uncertainty analysis is used to eliminate the climatic variables of input nodes from 1,000/PARMA(1,1)/GRNNM-GA training pattern. The sensitive and insensitive climatic variables are chosen from the uncertainty analysis of the input nodes. Finally, it can be to model the monthly PE and the alfalfa $ET_r$ simultaneously with the least cost and endeavor using the IOM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.6D
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• pp.577-585
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• 2010

Traffic accidents are caused by several factors such as drivers, vehicles, and road environment. It is necessary to investigate and analyze them in advance to prevent similar and repetitive traffic accidents. Especially, the human factor is most significant element and traffic accidents by drinking-driving caused from human factor have become social problem to be paid attention to. The study analyzes traffic accidents resulting from drinking-driving and the effects of driver's attributes and environmental factors on them. The study is composed as two parts. First, the log-linear model is applied to analyze that accidents by drinking or non-drinking driving associate with road geometry, weather condition and personal characteristics. Probability is tested for drinking-driving accidents relative to non-drinking drive accidents. The study analyzes probability differences between genders, between ages, and between kinds of vehicles through odds multipliers. Second, traffic accidents related to drinking are classified into property damage, minor injury, heavy injury, and death according to their severity. Heavy injury is more serious than minor one and death is more serious than heavy injury. The ordinal regression models are established to find effecting factors on traffic accident severity.

• Journal of the Daesoon Academy of Sciences
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• v.22
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• pp.87-131
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• 2014

한국은 백 년 이래로 군사적 침략과 경제적 대변혁을 맞았으며, 또한 종교와 문화적 측면에서 전통의 중흥기와 서학의 유입에 대한 문제를 경험하게 되었다. 이런 점에서 한국의 역사적 경험은 주변 국가의 국민들이 배울 만한 의미가 있다고 생각된다. 이와 연관하여 대순진리회가 역사를 계승하고 창신을 이루어나가는 측면의 문제는 정리해볼 만한 가치가 있다. 대순진리회의 종지는 '음양합덕, 신인조화, 해원상생, 도통진경'이다. 특히 대순진리회는 해원상생 사상으로 조화정신을 집중적으로 잘 나타내고 있다. 대순진리회의 해원은 고대 단주로부터의 원을 푸는 것에서 시작되며, 인류가 근본적으로 여러 세대에 걸친 원한을 풀어야만 행복하고 안락한 시대에 진입할 수 있다는 역사관을 보여주고 있다. 대순진리회가 해원을 푸는 방책으로 제시하는 상생은 당시의 갑오동학혁명이나 역사상 많은 종교에서 원한을 해결하는 방법과 구별되는 것이다. 과거에 있어서는 상극의 방법으로 원한을 해결하여 왔으나, 상극의 방식은 오히려 새로운 원한을 더욱 만들어 낼 수 있기 때문에, 현대에 있어 원한을 제거할 수 있는 방법은 악을 선으로써 대하는 것이라고 한다. 증산 성사 및 그 후학들은 사회의 질서를 새롭게 세우는 문제와 전통사회에서 인간 간의 조화를 방해하고 원한을 용인하는 구습을 개조하고 원을 소멸하는 문제에 주의를 기울였다. 이러한 변혁은 평등의 관념을 나타내고 있다. 증산께서는 전 세계적인 관점에서 민족과 국가 그리고 종교 간의 조화를 실현해야 할 것을 강조하셨다. 당시 동아시아 국가는 매우 폐쇄적인 상황에서 서양 국가의 침략을 받던 시기였는데, 증산 성사께서 미래의 세계는 마땅히 화합을 이루고 서로의 장점을 배우는 세계가 될 것임을 예견하셨다는 것은 그의 위대함을 보여주는 대목이다. 증산의 후천개벽사상 역시 조화의 정신을 나타내고 있다. 후천개벽사상은 전통적 참위를 현대적으로 개조한 것으로 민중을 적극적으로 인도하기 위한 것이다. 다음으로, 증산께서는 각 종교에 대해 관용적인 태도를 표하셨고, 또한 매우 진지한 태도로 타 종교로부터 자신이 주창하는 사상과 관련한 자원을 흡수하셨다. 동양의 전통적인 유불선 삼교를 가장 중요한 종교와 문화형태로 인정하시고, 그 삼교의 내용을 두로 포용하셨으며, 심지어 예수교와 서양문화까지 모두 아우르는 태도를 보여주셨다. 서양의 문화 역시 증산께서 추구하시는 신세계의 한 부분이었기 때문이다. 이러한 사실은 증산께서 당시 세계의 역사적 방향에 대해 통찰하고 있었고 이 통찰 속에서 종교 간의 관계가 조화롭게 되어야 함을 주창했음을 말해 준다. 대순사상에는 민간 무교의 내용 역시 풍부하게 들어있다. 부뚜막신, 사명, 아표신, 마장군, 백의군왕, 황천신 등 민간에서 유행했던 다양한 신령숭배의 내용을 흡수했을 뿐만 아니라, 주문과 부를 태우는 법술로 신명과 관련된 내용을 표현하고 있으며, 칠성과 관우의 신앙까지 수용하고 있다. 또한 증산 성사는 동학과 같은 신종교까지 받아들이셨다. 증산께서는 동학혁명의 비참한 최후를 완화시켰던 위대한 역사적 공적을 이루셨으며, 신종교 운동의 사회적 형태를 변화시켰을 뿐 아니라, 서로 다른 내력을 지닌 교도들간의 관계를 조화롭게 하였다. 이로 볼 때 결국 증산께서 주창한 대순사상은 사람들 간의 충돌과 모순을 소멸시키고, 조화와 상생의 사회 환경을 창조하고자 하는 것이었다고 할 수 있다.

• Journal of the Korean Institute of Gas
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• v.27 no.3
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• pp.27-34
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• 2023

Using ammonia as fuel for solid oxide fuel (SOFC) cells has become an attractive topic nowadays due to its high efficiency, environmental friendliness, and ease of storage and transportation. Several configurations of ammonia-fed SOFC systems have been proposed and investigated, demonstrating high electrical efficiency. However, to further enhance efficiency, it is crucial to understand the inefficient components of the system. The exergy concept is well-suited for this purpose, making exergetic analysis essential for ammonia-fed SOFC systems. This study conducts an exergetic analysis for three selected systems: a simple fuel cell system (FC), an anode off-gas recirculation system (RC-FC), and a recirculation system with water removal (RC-WR-FC). The results reveal that the exergetic efficiencies of the FC, RC-FC, and RC-WR-FC are 48.7%, 51.6%, and 58.4%, respectively. In all three systems, the SOFC stack is the main source of exergy destruction. However, other components with relatively low exergetic efficiency, such as the burner, air heat exchanger, and cooler/condenser, offer greater opportunities for improvement.

• Journal of Advanced Navigation Technology
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• v.26 no.6
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• pp.427-433
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• 2022

Obstacle detection, collision recognition, and avoidance technologies are required the collision avoidance technology for UAVs. In this paper, considering collinear multiple static obstacle, we propose an obstacle detection algorithm using LiDAR and a collision recognition and avoidance algorithm based on CPA. Preprocessing is performed to remove the ground from the LiDAR measurement data before obstacle detection. And we detect and classify obstacles in the preprocessed data using the K-means clustering algorithm. Also, we estimate the absolute positions of detected obstacles using relative navigation and correct the estimated positions using a low-pass filter. For collision avoidance with the detected multiple static obstacle, we use a collision recognition and avoidance algorithm based on CPA. Information of obstacles to be avoided is updated using distance between each obstacle, and collision recognition and avoidance are performed through the updated obstacles information. Finally, through obstacle location estimation, collision recognition, and collision avoidance result analysis in the Gazebo simulation environment, we verified that collision avoidance is performed successfully.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.43 no.6
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• pp.883-896
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• 2023

As human activities in Korea are spread throughout the mountains, forest fires often affect residential areas, infrastructure, and other facilities. Hence, it is necessary to detect fire-damaged areas quickly to enable support and recovery. Remote sensing is the most efficient tool for this purpose. Fire damage detection experiments were conducted on the east coast of Korea. Because this area comprises a mixture of forest and artificial land cover, data with low resolution are not suitable. We used Sentinel-2 multispectral instrument (MSI) data, which provide adequate temporal and spatial resolution, and the k-nearest neighbor (kNN) algorithm in this study. Six bands of Sentinel-2 MSI and two indices of normalized difference vegetation index (NDVI) and normalized burn ratio (NBR) were used as features for kNN classification. The kNN classifier was trained using 2,000 randomly selected samples in the fire-damaged and undamaged areas. Outliers were removed and a forest type map was used to improve classification performance. Numerous experiments for various neighbors for kNN and feature combinations have been conducted using bi-temporal and uni-temporal approaches. The bi-temporal classification performed better than the uni-temporal classification. However, the uni-temporal classification was able to detect severely damaged areas.

• Korean Journal of Organic Agriculture
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• v.31 no.4
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• pp.413-426
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• 2023

These experiments were conducted for 3 years from 2021 to 2023 to develop a method that can be safely used to prevent the leakage of Golden apple snails (Pomacea canaliculata) from eco-friendly rice plantations. In the southern part of Jeollanam-do, after planting rice, the young golden apple snails placed in the rice field become adults around mid-July and begin spawning. These individuals can overwinter in drains that do not dry out, but individuals hatched after mid-July will not mature enough to overwinter. The size of golden apple snails overwintered in the drainage canal was more than 2.5cm in shell height. Installing a net at the inlet could block 95% of the inflow of snails, and 99% of outflow was blocked by installing an improved water trap and net at the drain. During the mid-drying period and pre-harvest drying period, a water path was created with a power paddy pottery machine. 59.5% of snails were attracted to the waterway, and it took 130 minutes to build the waterway and collect the snails. Based on these results, seasonal paddy management tips for the safe use of giant snails in rice fields were suggested.

• Smart Media Journal
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• v.12 no.11
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• pp.185-197
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• 2023

This study was conducted using text mining and network theory to extract useful information for application for occupancy and performance of permit tasks contained in the permit contents from the permit register, which is used only for the simple purpose of recording occupancy permit information. Based on text mining, we analyzed and compared the frequency of vocabulary occurrence and topic modeling in five regions, including Seoul, Gyeonggi, Gyeongsang, Jeolla, Chungcheong, and Gangwon, as well as normalization processes such as stopword removal and morpheme analysis. By applying four types of centrality algorithms, including stage, proximity, mediation, and eigenvector, which are widely used in network theory, we looked at keywords that are in a central position or act as an intermediary in the network. Through a comprehensive analysis of vocabulary appearance frequency, topic modeling, and network centrality, it was found that the 'installation' keyword was the most influential in all regions. This is believed to be the result of the Ministry of Environment's permit management office issuing many permits for constructing facilities or installing structures. In addition, it was found that keywords related to road facilities, flood control facilities, underground facilities, power/communication facilities, sports/park facilities, etc. were at a central position or played a role as an intermediary in topic modeling and networks. Most of the keywords appeared to have a Zipf's law statistical distribution with low frequency of occurrence and low distribution ratio.