• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2020.11a
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• pp.58-60
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• 2020

겨울철 온대저기압은 그 세력이 강하여 해양사고의 주요 원인이 되는 등 선박의 안전 운항에 있어서 매우 중요하다. 이 연구에서는 겨울철(2019년 12월~2020년 2월)의 기상 데이터를 이용하여 제1태평양 한대전선대 부근의 온대저기압에 대하여 분석하였다. 분석 결과는 다음과 같다. 3개월 동안에 제1태평양 한대전선대 부근에서 발생한 온대저기압은 41개이고, 그 중 8개가 현저히 발달하였다. 발생 위치 별 온대저기압은 일본 동쪽 태평양이 가장 많았고(16개), 그 다음은 우리나라 주변, 동중국해, 일본 남쪽 해상 순이었다. 이동경로는 크게 5개로 구분할 수 있는데, 공통적으로 북동진하는 패턴을 보였다.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.936-943
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• 2009

In this study, a risk assessment model based on the ETA (Event Tree Analysis) and FTA (Fault Tree Analysis) is developed according to the procedure of hazard analysis and risk assessment in order to estimate the risk quantitatively. The FTA technique is applied to estimate the branch probability (frequency) and the ETA technique is applied to estimate the consequence for each branch path on the ET (Event Tree). A risk assessment model is developed by the combination of those ETA and FTA. In addition, the reliability and the validity of the risk assessment model are verified by comparing the risk estimated through the developed model with the actual equivalent fatality.

• Proceedings of the Korean Society for Food Science of Animal Resources Conference
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• 2005.05a
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• pp.191-194
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• 2005

본 연구는 polymerase chain reaction(PCR)기법을 이용하여 SRY 및 ZFY의 성 결정 유전자의 특정 염기서열을 포함하는 primer를 이용하여 Y-염색체 특이적인 쇠고기 성판별 기술을 개발하기 위해 수행하였다. 성 결정 유전자의 영역에 특정 염기서열을 포함하는 primer를 설계 합성하고 이들 primer를 이용하여 PCR 증폭을 실시한 다음, 각각의 증폭산물을 1.5% agarose gel에 전기영동 하여 웅성 특이적 DNA band의 증폭여부를 확인하였다. SRY 유전자에서 웅성개체 쇠고기는 1,348 bp 크기의 단편을 가진 DNA band가 검출되었으나, 자성개체의 경우 DNA band가 전혀 검출되지 않은 것을 확인 할 수 있었다. 또한, ZFY 유전자에서 웅성개체의 쇠고기는 979 bp 크기의 단편을 가진 DNA band가 모두 검출되었으나, 자성개체의 쇠고기에서는 역시 DNA band가 전혀 검출되지 않았다. 즉,SRY 및 ZFY 유전자는 모두 수소에서 유래한 쇠고기에서 웅성 특이적인 DNA band가 정확히 검출된 반면 암소에서 유래한 쇠고기에서는 웅성 특이적 DNA band가 전혀 검출되지 않았다. 따라서, 본 연구에서 개발한 SRY 또는 ZFY의 웅성 특이적 성 결정유전자를 이용하는 쇠고기 성 감별기술은 시중에서 유통 판매되고 있는 쇠고기의 암수 성감별을 위한 유용한 DNA marker(DNA 표지인자)로 활용할 수 있을 것이다.

• Economic and Environmental Geology
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• v.34 no.3
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• pp.307-313
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• 2001

Reactive medium including zero-valent metals such as zero-valent iron ($Fe^0$) degrades chlorinated solvents as a contaminant plume flows through the treatment medium. Although the Feo based reactive barrier has been demonstnlted to be a cost effective for trichloroethenc (TCE)-contaminaled plume remediation, current approach is limited by low process eftlciency and uncertain, effective life of the medium. The objective of this study is to develop an enhanced treatment method of TeE-contaminated groundwater using Feo and direct current. The bench-scale test using flow-through $Fe^0$ reactor column confirmed that the application of direct current with $Fe^0$ is highly effective in enhancing the rate of TeE dechlorination. The dechlorination mechanism appears to be reductive, with the electrons supplied by the iron oxidation and external power supply serving as the additional source of electrons.

• KSBB Journal
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• v.15 no.2
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• pp.201-207
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• 2000

The traditional ripening method of clay was analyzed. An advanced refining method of clay using enrichment cultures of iron r reducing bacteria was developed. After the traditional ripening, the whiteness of the clay was increased due to removal of | iron impurities by inhabitant dissilmaltien with iron reducing bacteria. Other characteristics of the refined clay such as v viscosity, plasticity, and strength were also improved by iron reducing bacteria. An advanced method of clay refinement with a anaerobic enrichment cultivation of iron reducing bacteria supplemented with an extra carbon source such as glucose was s suggested. When the clay was treated by the advanced method. the refinement time could be reduced to 1/6 of that r required by the traditional method. The physical properties of the refined clay by the advanced method were better than t those of the traditionally refined clay.

• Economic and Environmental Geology
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• v.36 no.5
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• pp.381-385
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• 2003

We investigated possible application of waste ferrite in treating Cd and Pb in wastewater. Adsorption of Cd and Pb on Mn-Ferrite are influenced by several controlling factors such as contact time, heavy metal concentrations, pH and temperature. Both Cd and Pb achieved adsorption equilibrium within 5 minutes. Based upon this kinetic data, 24 hours of contact time was allowed for other experiment. The adsorption of Cd and Pb was high at high pH and high ion concentrations. The reaction was also affected by temperature. Adsorption isotherms fits well with the Freundlich isotherm equation. pH is the main controlling factor in Cd, Pb adsorption on the Mn-ferrite. Cd showed S type adsorption curve while Pb showed sorption edges, depending on the Pb concentrations.

• Journal of Korean Association for Spatial Structures
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• v.6 no.4 s.22
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• pp.73-80
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• 2006

It is an object of the present paper to investigate a electrochemical properties of Mg-based sacrificial anodes and the effect of calcium added from calcium chloride into magnesium on the melt protection during the melting. Electrochemical data will be correlated with processing control variables, and the microstructural change by the addition of CaCl2. Small addition of calcium into magnesium from CaCl2 imparts beneficial effect in electrochemical properties of Mg alloys, primarily, through microstructural modifications. In addition, the protection effect of the melts surface of Ca with low melting point modification is obtained by adding Ca not more than 0.6%.

• KIPS Transactions on Software and Data Engineering
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• v.5 no.9
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• pp.433-440
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• 2016

Railway point machines act as actuators that provide different routes to trains by driving switchblades from the current position to the opposite one. Since point failure can significantly affect railway operations with potentially disastrous consequences, early stress detection of point machine is critical for monitoring and managing the condition of rail infrastructure. In this paper, we propose a stress detection method for point machine in railway condition monitoring systems using sound data. The system enables extracting sound feature vector subset from audio data with reduced feature dimensions using feature subset selection, and employs support vector machines (SVMs) for early detection of stress anomalies. Experimental results show that the system enables cost-effective detection of stress using a low-cost microphone, with accuracy exceeding 98%.

• Journal of the Korean Society for Railway
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• v.18 no.5
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• pp.502-511
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• 2015

The purpose of this study is to prioritize the importance of urban railway service quality through statistical analysis. This was done to maximize customer satisfaction by providing customers of urban railway services (including LRT), operated by the local government, with a better customized service quality. It was hoped that this project would boost the need for public transportation by increasing customer satisfaction, which would eventually lead to more profitable revenue. The results of validity certification of expectations and perceptions before and after the use of government funded urban railway and private sector invested urban railways show that there are gaps for 18 items for the government funded urban rail projects (p<.01), while there is no significant difference for 2 items between expectation and perception (p>.05); private sector invested urban railway projects show differences for all 20 items (p<.001). Therefore, IPA analysis is conducted to improve the service quality; this should lead to a remedy that focuses on service quality. The findings of this study will contribute to providing management strategies for boosting customer satisfaction and creating revenue through customized service quality in the urban railway operating industry (including LRT), which is currently suffering from chronic deficits.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.1
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• pp.73-81
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• 2000

The removal of ferrous iron (Fe(II)) in groundwater is generally achieved by simple aeration or the addition of oxidizing agent. Aeration followed by solid-liquid separation is the most commonly used as physico-chemical treatment method for iron removal. In general aeration has been shown to be very efficient in insolubilizing ferrous iron at the pH level greater than 6.5. In this study pH was maintained over 6.5 using limestone granules under constant aeration to oxidize ferrous iron. In batch experiments, oxidation rate of ferrous iron was investigated under different conditions including limestone granule size. initial concentration of the ferrous iron, pH, temperature and ionic strength in groundwater. The pH in groundwater was presumed as the most important factor determining oxidation rate of ferrous iron. According as the size of the limestone granules decreased, the pH of the iron contaminated water increased quickly and oxidation of the ferrous iron was achieved immediately too. The oxidation rate of the ferrous iron was found to be proportion to initial concentration of the iron contaminated water, temperature and ionic strength, respectively.