• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.253-257
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• 2010

최근 들어 이상 강우 현상으로 인한 기록적인 집중 강우와 더불어 토지 이용 변화로 인해 탁수의 발생 빈도가 증가하고 있다. 강우 유출로 유입한 탁수는 저수지 내 장기간 체류하면서 하류 하천의 수질 및 수생태계 뿐만 아니라 저수지 내부의 영양단계에도 많은 영향을 준다. 특히, 성층화된 저수지의 경우 높은 영양염류 농도를 포함한 탁수는 밀도류 거동 특성을 보이면서 수평 및 수직 혼합 과정을 거치면서 국부적인 부영양화 현상과 조류의 수화 현상의 원인이 되고 있다. 따라서 대형 저수지의 수질관리에 있어 하천 유입 탁수의 밀도류 해석, 저수지의 수온 성층 구조 변화, 부유입자의 동력학적 해석이 중요한 요소로 부각되어 왔다. 본 연구에서는 소양호를 연구 대상 지역으로 선정하여 2005년과 2007년 수문 사상을 바탕으로 2차원 횡방향 수치 모형을 구축하였다. 수치모형을 통해 수온 성층 구조의 재현성을 확인하였으며, 다양한 탁수 거동 모형을 구축하여 적용성을 평가하였다. 유입수의 SS(Suspended Solid)를 단일 입경으로 가정한 TM-1 모형, SS의 입경분포에 따라 3개의 그룹(SSi)으로 구분한 TM-2 모형, 3개 그룹을 포함하면서 저수지내 탁수 장기화로 인한 탁수 저감 효과를 1차 반응상수로 매개 변수화(유기물 함량($a_0$) ${\times}$ 분해속도(${\lambda}_a$))하여 수정된 지배방정식을 적용한 TM-3 모형을 사용하였다. 각각의 탁수 거동 모형은 2005년과 2007년 수문 조건에서 수온 성층 구조를 잘 재현하였다. TM-1 모형과 TM-2 모형을 비교해보면, 탁수 중심축의 최고 탁도에 대한 예측 성능은 TM-2 모형이 우수한 결과를 나타냈었다. 하지만, 장기 탁수 모의 시 저수지 수중 잔류 SS가 지속적으로 높게 나타나 중층 탁도를 과대평가하는 경향을 보였다. TM-3 모형이 TM-2 모형에 비해 수심별 탁도 분포에 대한 중심축 탁도가 저평가되는 경향을 보였지만 저수지 내 잔류 탁도에 대한 영향 부분에서는 개선된 결과를 나타내었다. 본 연구 결과는 저수지 탁수 밀도류 해석 및 운영 시스템에 활용 될 수 있으며, 선택 취수 설비 등의 수리 구조물의 영향 평가에 활용할 수 있다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.05a
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• pp.142-143
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• 2019

Busan Port ranked 6th in the world with 21.67 million TEUs of container handling in 2018, but the ship supply industry has fallen short of that. Despite its technological prowess, Korea's ship supply industry lacks competitive edge in many aspects such as government support, integrated platform, and infrastructure compared to overseas ship supply industries. The use of code, which is not standardized, can be cited as a leading factor that undermines the competitiveness of Korea's ship supply industries. In the ship supply industry, the use of non-standardized codes can make it difficult to manage or analyze meaningful statistics, and, by extension, can lead to the loss of new business opportunities. Therefore, in this study, we intend to use local ship supply transaction data to study how to standardize item code to solve the problem.

• Journal of the Korean Society for information Management
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• v.21 no.3
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• pp.1-14
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• 2004

Visualization of documents will help users when they do search similar documents. and all research in information retrieval addresses itself to the problem of a user with an information need facing a data source containing an acceptable solution to that need. In various contexts. adequate solutions to this problem have included alphabetized cubbyholes housing papyrus rolls. microfilm registers. card catalogs and inverted files coded onto discs. Many information retrieval systems rely on the use of a document surrogate. Though they might be surprise to discover it. nearly every information seeker uses an array of document surrogates. Summaries. tables of contents. abstracts. reviews, and MARC recordsthese are all document surrogates. That is, they stand infor a document allowing a user to make some decision regarding it. whether to retrieve a book from the stacks, whether to read an entire article, etc. In this paper another type of document surrogate is investigated using a grouping method of term list. lising Multidimensional Scaling Method (MDS) those surrogates are visualized on two-dimensional graph. The distances between dots on the two-dimensional graph can be represented as the similarity of the documents. More close the distance. more similar the documents.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.152-161
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• 2023

In general, large-capacity hydrogen storage vessels, typically in the form of vertical cylindrical vessels, are constructed using steel materials. These vessels are anchored to foundation slabs that are specially designed to suit the environmental conditions. This anchoring method involves pre-installed anchors on top of the concrete foundation slab. However, it's important to note that such a design can result in concentrated stresses at the anchoring points when external forces, such as seismic events, are at play. This may lead to potential structural damage due to anchor and concrete damage. For this reason, in this study, it selected an vertical hydrogen storage vessel based on site observations and created a 3D finite element model. Artificial seismic motions made following the procedures specified in ICC-ES AC 156, as well as domestic recorded earthquakes with a magnitude greater than 5.0, were applied to analyze the structural behavior and performance of the target structures. Conducting experiments on a structure built to actual scale would be ideal, but due to practical constraints, it proved challenging to execute. Therefore, it opted for an analytical approach to assess the safety of the target structure. Regarding the structural response characteristics, the acceleration induced by seismic motion was observed to amplify by approximately ten times compared to the input seismic motions. Additionally, there was a tendency for a decrease in amplification as the response acceleration was transmitted to the point where the centre of gravity is located. For the vulnerable components, specifically the sub-system (support columns and anchorages), the stress levels were found to satisfy the allowable stress criteria. However, the concrete's tensile strength exhibited only about a 5% margin of safety compared to the allowable stress. This indicates the need for mitigation strategies in addressing these concerns. Based on the research findings presented in this paper, it is anticipated that predictable load information for the design of storage vessels required for future shaking table tests will be provided.

• Journal of KIISE:Databases
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• v.37 no.3
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• pp.127-136
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• 2010

With rapid growth of information and computer communication technologies, the numbers of digital documents including multimedia data have been recently exploded. In particular, news video database and news video mining have became the subject of extensive research, to develop effective and efficient tools for manipulation and analysis of news videos, because of their information richness. However, many research focus on browsing, retrieval and summarization of news videos. Up to date, it is a relatively early state to discover and to analyse the plentiful latent semantic knowledge from news videos. In this paper, we propose the news video mining system based on multi-modal approach and text mining, which uses the visual-textual information of news video clips and their scripts. The proposed system systematically constructs a taxonomy of news video stories in automatic manner with hierarchical clustering algorithm which is one of text mining methods. Then, it multilaterally analyzes the topics of news video stories by means of time-cluster trend graph, weighted cluster growth index, and network analysis. To clarify the validity of our approach, we analyzed the news videos on "The Second Summit of South and North Korea in 2007".

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.8
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• pp.3578-3585
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• 2012

The purpose of this study was to establish the critical limit at CCP (Critical Control Point) of HACCP (Hazard Analysis Critical Control Point) system for instant noodle and it was conducted at P company in Ichen(Gyeonggi-do), Korea. According to the CCP, Fried process were experimented to removal and decrease of microbiological and chemical hazards by measuring of each temperature and times. As a result, the standard plate count and pathogenic microorganism were not detected by fried processing (Temperature : $145{\pm}10^{\circ}C$, Time : $75{\pm}30$ sec). The acid value of chemical hazards produced by fried processing was able to manage, showed lower (0.2) than the legal limit (0.6). Air-borne bacterial examination results detected(3 CFU/mL, 3 CFU/mL) in the Frying Room and Steam Room. Therefore, the CCP-BC of fried process would be a great alternative to prevent and remove hazard analysis, such as general and pathogenic microorganism (E. coli O157:H7, B. cereus, Listeria monocytogenes, Salmonella spp, Sthaph. aureus etc), chemical hazard analysis. In conclusion, it suggested that HACCP plan was necessary for management standard and systematic approach in establishement of critical limit, solving the problem, method of verification, education and records management by fried processing.

• Economic and Environmental Geology
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• v.56 no.4
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• pp.435-445
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• 2023

A delta is a depositional landform that is formed when sediment transported by a river is deposited in a relatively low-energy environment, such as a lake, sea, or a main channel. Among these, a delta formed at the confluence of rivers has a great importance in river management and research because it has a significant impact on the hydraulic and sedimentological characteristics of the river. Recently, the equilibrium state of the confluence area has been disrupted by large-scale dredging and construction of levees in the Nakdong River. However, due to the natural recovery of the river, the confluence area is returning to its pre-dredging natural state through ongoing sedimentation. The time-series data show that the confluence delta has been steadily growing since the dredging, but once it reaches a certain size, it repeats growth and retreat, and the overall size does not change significantly. In this study, we developed a model to explain the sedimentation-erosion processes in the confluence area based on the assumption that the confluence delta reaches a dynamic equilibrium. The model is based on two fundamental principles: sedimentation due to supply from the tributary and erosion due to the main channel. The erosion coefficient that represents the Nakdong River confluence areas, was obtained using data from the tributaries of the Nakdong River. Sensitivity analyses were conducted using the developed model to understand how the confluence delta responds to changes in the sediment and water discharges of the tributary and the main channel, respectively. We then used annual average discharge of the Nakdong River's tributaries to predict the dynamic equilibrium positions of the confluence deltas. Finally, we conducted a simulation experiment on the development of the Gamcheon-Nakdong River delta using recorded daily discharge. The results showed that even though it is a simple model, it accurately predicted the dynamic equilibrium positions of the confluence deltas in the Nakdong River, including the areas where the delta had not formed, and those where the delta had already formed and predicted the trend of the response of the Gamcheon-Nakdong River delta. However, the actual retreat in the Gamcheon-Nakdong River delta was not captured fully due to errors and limitations in the simplification process. The insights through this study provide basic information on the sediment supply of the Nakdong River through the confluence areas, which can be implemented as a basic model for river maintenance and management.

• Korean Journal of Environmental Biology
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• v.35 no.4
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• pp.549-556
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• 2017

Rivers continuously transport terrestrial organic carbon matter to the estuary and the ocean, and they play a critical role in productivity and biodiversity in the marine ecosystem as well as the global carbon cycle. The amount of terrestrial organic carbon transporting from the rivers to ocean is an essential piece of information, not only for the marine ecosystem management but also the carbon budget within catchment. However, this phenomenon is still not well understood. Most large rivers in Korea have a well-established national monitoring system of the river flow and the TOC (Total Organic Carbon) concentration from the mountain to the river mouth, which are fundamental for estimating the amount of the TOC flux. We estimated the flux of the total terrestrial organic carbon of five large rivers which flow out to the Yellow Sea, using the data of the national monitoring system (the monthly mean TOC concentration and the monthly runoff of river flow). We quantified the annual TOC flux of the five rivers, showing their results in the following order: the Han River ($18.0{\times}10^9gC\;yr^{-1}$)>>Geum River ($5.9{\times}10^9gC\;yr^{-1}$)>Yeongsan River ($2.6{\times}10^9gC\;yr^{-1}$)>Sumjin River ($2.0{\times}10^9gC\;yr^{-1}$)>>Tamjin River ($0.2{\times}10^9gC\;yr^{-1}$). The amount of the Han River, which is the highest in the Korean rivers, corresponds to be 4% of the annual total TOC flux of in the Yellow River, and moreover, to be 0.6% of Yangtze River.

• Journal of the Korean Association of Geographic Information Studies
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• v.8 no.3
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• pp.96-106
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• 2005

The ability of remote sensing and GIS technique, which used to provide valuable informations in the time and space domain, has been known to be very useful in providing permanent records by mapping and monitoring flooded area. In 2000, floods were at the worst stage of devastation in Tonle Sap Lake, Mekong River Basin, for the second time in records during July and October. In this study, Landsat ETM+ and RADARSAT imagery were used to obtain the basic information on computation of the inundation area and volume using ISODATA classifier and segmentation technique. However, the extracted inundatton area showed only a small fraction than the actually inundated area because of clouds in the imagery and complex ground conditions. To overcome these limitations, the cost-distance method of GIS was used to estimate the inundated area at the peak level by integrating the inundated area from satellite imagery in corporation with digital elevation model (DEM). The estimated inundation area was simply converted with the inundation volume using GIS. The inundation volume was compared with the volume based on hydraulic modeling with MIKE 11. which is the most poppular among the dynamic river modeling system. The method is suitable for estimating inundation volume even when Landsat ETM+ has many clouds in the imagery.