• Journal of Korea Multimedia Society
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• v.10 no.9
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• pp.1106-1116
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• 2007

Recently e-commerce trade on the web has grown rapidly in scale and complexity, just as web site designs and web servers have become more complicated. In view of these complexities, it is obviously difficult to analyse web user's data since they web users employ so many different web paths. The existing association rule investigation algorithms identify all items with a high correlation. However even though users often only want to find items in which they have interest, it is still difficult to find the rules they want out of all of the many association rules found by existing algorithms. In this paper, we propose a system linking each node with the sequence association rule, linking all routes after finding a path corresponding to a user with the association rule-one of the data mining techniques which identify user patterns in web user paths. The suggested system helps us construct individualized or customer-subdivided sites using the sequence association rule in order to harmonize the paths of web users with user characters.

• Journal of KIISE:Computer Systems and Theory
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• v.32 no.10
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• pp.530-540
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• 2005

Virtual colonoscopy is an easy and fast method to reconstruct the shape of colon and diagnose tumors inside the colon based on computed tomography images. This is a non-invasive method, which resolves weak points of previous invasive methods. The path for virtual colonoscopy should be generated rapidly and accurately for clinical examination. However, previous methods are computationally expensive because the data structure such as distance map should be constructed in the preprocessing and positions of all the points of the path needs to be calculated. In this paper, we propose the automatic path generation method based on visibility to decrease path generation time. The proposed method does not require preprocessing and generates small number of control points representing the Path instead of all points to generate the path rapidly. Also, our method generates the path based on visibility so that a virtual camera moves smoothly and a comfortable and accurate path is calculated for virtual navigation. Also, our method can be used for general virtual navigation of various kinds of pipes.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.722-740
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• 2005

본 논문은 최근의 석유탐사 및 개발사업 현장에서 사용되고 있는 최신의 측량기술 및 해양공사의 측량 기술 표준화 동향을 소개하고, 이에 기반하여 동해1 가스전 해저배관 공사에 적용한 사례를 기술하였다. 해저배관 시설공사를 수행하기 위한 사전측량 및 시공지원 측량은 다양한 탐사장비가 동원되며, 각 장비들의 운영, 자료처리, 해석, 도면화를 위하여 실시간지원이 가능한 시스템을 운영하는 기술이 요구된다. 이를 위하여 해저배관 시공단계별(Pre-Installation Survey, Touch-down Monitoring, As-laid As-Built Survey, Post-installation Survey) 요구되는 측량성과 및 이를 획득하기 위한 소해측량 시스템의 성능평가 및 정확도 분석을 수행하였다. 또한, 해저지형 탐사를 위해 동원된 소해측량시스템(Swath Sonar System)에서 취득되는 수심(Bathymetry) 및 후방산란 음압(Backscattered Amplitude) 자료를 맵핑하여 해저배관의 설치 경로를 측량하는 기법에 대하여 소개하고, 추후 해저배관 보호 및 관리시의 효율적인 모니터링 기법을 제시한다.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.499-500
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• 2018

최근 지반이 가라앉아 지면에 구멍이 발생하는 싱크홀(Sink Hole)의 발생이 빈번하게 발생하고 있으며, 이에 대한 피해사례도 증가하고 있다. 이를 예방하고 대응하기 위하여 국가적으로 대대적인 지반조사를 하고 있으며 해당 지반을 탐사하기 위하여 지표투과레이더와 내시경 등을 활용한 방법을 사용하고 있다. 본 논문에서는 현재까지 가장 효율적인 방법으로 알려진 지표투과레이더의 데이터를 그래프 형태로 표현하고 분석하여 효과적으로 탐사를 할 수 있는 시스템을 제안한다.

• Geophysics and Geophysical Exploration
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• v.22 no.3
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• pp.132-148
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• 2019

Recently, safety and environmental concerns have become major social issues. Especially, a special underground-safety law has been made and enacted to prevent ground subsidence around construction sites. For environmental problems, several researches have started or will start on characterization of contaminated sites, in-situ environmental remediation in subsurface, and monitoring of remediation results. As a part of the researches, geophysical surveys, which have been mainly applied to explore mineral resources, geological features or ground, are used to characterize not only contaminated areas but also fluid flow paths in subsurface environments. As a basic study for the application of geophysical surveys to detect contamination in subsurface, this paper analyzes previous researches to understand changes in geophysical properties of contaminated zones by various contaminants such as leachate, heavy metals, and non-adequate phase liquid (NAPL). Furthermore, this paper briefly introduces how geophysical surveys like direct-current electrical resistivity, induced polarization and ground penetration radar surveys can be applied to detect each contamination, before analyzing case studies of the applications in contaminated areas by NAPL, leachate, heavy metal or nitrogen oxides.

• Geophysics and Geophysical Exploration
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• v.14 no.2
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• pp.158-163
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• 2011

The small-loop electromagnetic (EM) survey is an effective method to delineate contamination areas and pathways of contaminant plumes from landfill. A multi-frequency small-loop EM survey was applied to find them at landfill area, located in delta region, and checked the results with in-situ surveys including 24 trench excavations and 12 drilling boreholes. The correlation between these two results indicates this survey would be suitable to investigate the contamination area. However, it would be difficult to analyze low resistivity less than 10 ohm-m below 10 m depth in delta area without drilling survey because of a limitation to expand the penetration depth lower than 10 m depth due to the separation of 1.66 m between the two coils of GEM-2.

• Korean Journal of Remote Sensing
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• v.11 no.3
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• pp.129-145
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• 1995

SeaBeam2000, a multibeam echo sounder, is a new generation seabed mapping system of which a single swath covers an angular range of -60.deg. to 60.deg. from the vertical direction with 121 beams. It provides high-density and high-quality bathymetric data along with sidescan acoustic data. The purpose of the research is to develop a system for processing multibeam underwater acoustic and bathymetric data using digital signal processing techniques. Recently obtained multibeam echo sounder data covering a survey area in the East Sea of Korea ($37{\circ}$.00'N to $37{\circ}$30'N and $129{\circ}$40'E to $130{\circ}$30'E) are preliminarily processed using the developed system and reproduced in the raster image format as well as three dimensionally visualized form.

• Journal of the Korean Geotechnical Society
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• v.38 no.11
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• pp.137-147
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• 2022

Various geophysical exploration methods are used to determine the exact location of underground utilities, and many studies have been performed to improve the accuracy. This study analyzed the feasibility of exploring underground utilities through a new exploration method using cosmic ray muon. A prototype of a portable muon detector was manufactured by combining a scintillator and a silicon photomultiplier. Further, a calibration operation was performed on the muon count rate. The ground thickness of the ground model was measured using the muon detector prototype, where the value could be estimated with an error of about 3%, close to the actual. In addition, the theoretical basis for tomography analysis technology was analyzed to utilize the muon detector for exploring underground utilities, and a zenith angle correction method was presented. This study revealed that the technology of exploration using muon can analyze density with high resolution and will be used for exploring underground utilities.

• Korean Journal of Remote Sensing
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• v.27 no.1
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• pp.59-68
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• 2011

The analysis of optimal infiltration path is one of the representative fields in which the GIS technology can be useful for the military purpose. Usually the analysis of the optimal path is done with network data. However, for military purpose, it often needs to be done with raster data. Because raster data needs far more computation than network data, it is difficult to apply the methods usually used in network data, such as Dijkstra algorithm. The genetic algorithm, which has shown great outcomes in optimization problems, was applied. It was used to minimize the detection probability of infiltration route. 2D binary array genes and its crossover and mutation were suggested to solve this problem with raster data. 30 tests were performed for each population size, 500, 1000, 2000, and 3000. With each generation, more adoptable routes survived and made their children routes. Results indicate that as the generations increased, average detection probability decreased and the routes converged to the optimal path. Also, as the population size increases, more optimal routes were found. The suggested genetic algorithm successfully finds the optimal infiltration route, and it shows better performance with larger population.

• The Journal of Engineering Geology
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• v.16 no.4 s.50
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• pp.455-463
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• 2006

The electrical resistivity prospecting method with dipole-dipole array was applied to the Mooreung landfill site in order to survey the existence of leachate around the landfill site. Moreover, if there is leachate within Mooreung landfill site, the analysis of potential pathways to exterior environments was tried. Within the landfill site, the over-all characteristics of the electrical resistivity anomalies suggest that the leachate induced from the landfill materials has infiltrated the basement rock and fill the pores of basement rock in some parts of the landfill site. The consistency of the anomaly locations (left part of each survey line), anomaly geometries, and absolute resistivity value of anomaly through the 3 survey lines suggests that the resistivity anomaly be connected from the upstream to the downstream and correspond to the leachate material. Finally, the result from the electrical resistivity survey line near the gateway of the landfill site suggests that some of the leachate induced from landfill material leaks to the exterior groundwater system. It is necessary that more surveys using both geochemical and geophysical methods should be performed to find out potential pathways and depths of the leachate more precisely.