• Journal of KIISE
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• v.42 no.5
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• pp.652-663
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• 2015

Due to the popularity of location-based services, the amount of generated spatial data in daily life has been dramatically increasing. Therefore, spatial database outsourcing has become popular for data owners to reduce the spatial database management cost. The most important consideration in database outsourcing is meeting the privacy requirements and guarantying the integrity of the query result. However, most of existing database transformation techniques do not support both of the data privacy and integrity of the query result. To solve this problem, we propose a spatial data transformation scheme that utilizes the shearing transformation with rotation shifting. In addition, we described the attack models to measure the data privacy of database transformation schemes. Finally, we demonstrated through the experimental evaluations that our scheme provides high level of data protection against different kinds of attack models, compared to the existing schemes, while guaranteeing the integrity of the query result sets.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.167.2-167.2
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• 2012

경희대학교와 UC Berkeley, Imperial College London에서 공동으로 진행하는 TRIO-CINEMA Mission(TRiplet Ionosphere Observatory-Cubesat for Ion, Neutral, Electron and MAgnetic fields)은 총 3기의 초소형 위성으로 구성되어 있다. 3기의 위성은 고도 650~800km 상공의 태양동주기 궤도운동을 예상하고 있으며, 지구 근접공간의 입자 검출과 자기장 측정의 과학 임무를 맡게 된다. TRIO-CINEMA 비행 모델(Flight Model)의 환경시험은 진동시험과 열진공시험으로 진행되었다. 진동시험은 X, Y, Z 세 축에 대해 Sine 과 Random 모드로 진행되었다. TRIO-CINEMA가 탑재 될 러시아의 드네프르 로켓의 요구사항은 각 축에서 20Hz 이상의 고유진동수, Sine의 경우 최대 0.8G와 4oct/min Sweep Rate, Random의 경우 5.2Grms 와 35초의 지속시간에서의 안정성을 만족하는 것이다. 시험 결과 TRIO-CINEMA가 요구사항을 모두 만족시키는 것을 확인하였다. 또한, 열 주기 시험(Thermal Cycling Test)을 진행하여 우주공간에서 위성 시스템이 정상 동작하는지에 대한 신뢰성을 검증하였다. 열주기 시험은 미국 MIL표준 값을 참고하여 $10^{-6}Torr$에서 $-20{\sim}30^{\circ}C$의 온도를 주었으며, 시험을 진행하는 동안과 시험 후에 위성이 정상작동 함을 확인하였다. 이에 본 연구의 시험 방법과 그 결과를 기술하였다.

• Korean Journal of Remote Sensing
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• v.16 no.1
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• pp.87-98
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• 2000

Image merging techniques have been developed to integrate the advantage of different data type. The objective of this study is to present the optimal method for merging high spatial resolution panchromatic image, such as the latest commercial satellite data, and low spatial resolution mulitspectral images. For this study, a set of 2m resolution panchromatic and 8m resolution mulitspectral data were simulated by using airborne mulitspectral data. Five merging methods of MWD, IHS, PCA, HPF, and CN were applied to produce four bands of high spatial resolution mulitspectral data. Merging results were evaluated by visual interpretation, image statistics, semivariogram, and spectral characteristics. From the aspects of both spatial resolution and spectral information, the wavelet-based MWD merging method have shown very similar results compared with the original data used for the merging.

• Journal of Korean Tunnelling and Underground Space Association
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• v.16 no.3
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• pp.299-310
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• 2014

Nationally, tunnel and underground constructions are necessary for the environmental sustainability and the efficient use of land space. For the importance of eco-friendly circumstances, 2-arch or large road tunnel has been designed so far. However, such a 2-arch or large tunnel has problems in terms of cost, constructability, construction period, and maintenance. Therefore, in this study, tunnel behavior and stability of rock pillar according to the pillar width and cover depth for parallel tunnels are investigated by performing FE analysis and using empirical formula. According to the results, Rock pillar is reinforced for distributed vertical load by Tie-Bolt due to unpredicted ground deformation, and the reinforced rock pillar's behaviour from the FE analysis shows a quite good agreement with field measurement. According to ground conditions, if the pillar width of the parallel tunnels is reduced, it can be more efficient in use of the tunnel space compared to previous tunnels.

• The Southeast Asian review
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• v.23 no.1
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• pp.277-311
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• 2013

한류에 대한 기존 언론보도 및 연구 경향은 다음과 같이 요약된다. 중국 일본 및 서구에서의 한류 현상에 대한 편중된 관심과 한류 분석틀로서 문화근접성 이론에 대한 지나친 의존이다. 이러한 상황은 한류 현상에 대한 객관적인 인식과 경험적인 분석을 방해하고 있다. 이러한 문제의식에 기초한 본 연구는 동남아시아, 특히 싱가포르의 한류 현상에 대한 분석을 통해 보다 객관적이고 다각화된 한류 연구를 모색한다. 지리적으로 동남아시아에 위치하고 있지만 문화적으로 동북아시아적 요소를 포괄하고 있는 싱가포르는 아시아 내 초국적 대중문화 교통을 연구하는 데 있어 전략적으로 중요한 공간이다. 본 논문은 싱가포르의 한국 대중문화 수용자들에 대한 포커스그룹 인터뷰, 문헌조사와 참여관찰을 통해 한류 형성의 이유 및 한류 팬덤이라는 문화적 실천이 갖는 의미를 탐구한다. 수용자에 대한 분석은 그가 배치된 싱가포르 미디어 구조에 대한 역사적, 기술적, 정치경제적 맥락화를 통해 보다 체계화된다. 본 연구를 통해 동남아시아에서 발견되고 있는 "외래문화 수용의 진부화"(banalization of foreign cultural reception)라는 상황이 동남아시아 내 한류 전개에 중요한 영향을 끼쳤으며, 동남아시아 미디어산업의 저개발 상황이 한국 대중문화 수용에 우호적 조건으로 작용했음을 확인할 수 있었다. 마지막으로, 연구자는 동아시아 내 문화교통의 연속성 (continuum of cultural traffic within East Asia) 안에 한류 연구를 배치할 것을 제시한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.11
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• pp.3373-3383
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• 2009

The aim of the current study is to look at the mediating effects of structural features (i.e. decentralization, formalization, and specialization) on the relationship between product variety and the performance of product family. This study investigates the impact of decentralization and formalization for platform and derivative projects separately and in the context of the performance of the product family as a whole, as opposed to individual projects. In addition to relationships between people and groups, the current study considers physical element of an organization such as geographical location in which business tasks are conducted. The current study focuses on spatial differentiation which refers to the number of different sites or locations operated by an organization. Based on a cross-industry sample of 103 Korean manufacturers, this study examines the role of organizational structure features in which firms successfully increase product variety. The study examines that formalization in platform projects and decentralization in derivative projects enhance high variety firms' product family performance. The study finds significant mediating effect of spatial proximity on the relationship between product variety and product family performance.

• Journal of the Korean Association of Geographic Information Studies
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• v.24 no.3
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• pp.58-72
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• 2021

In July 2021, UNCTAD classified Korea as a developed country. After the Korean War in the 1950s, economic development was promoted despite difficult conditions, resulting in epoch-making national growth. However, in order to respond to the rapidly changing global economy, it is necessary to continuously study the domestic industrial ecosystem and prepare strategies for continuous change and growth. This study analyzed the industrial ecosystem of the automobile industry where it is possible to obtain transaction data between companies by applying complexity spatial network analysis. For data, 295 corporate data(node data) and 607 transaction data (link data) were used. As a result of checking the spatial distribution by geocoding the address of the company, the automobile industry-related companies were concentrated in the Seoul metropolitan area and the Southeastern(Dongnam) region. The node importance was measured through degree centrality, betweenness centrality, closeness centrality, and eigenvector centrality, and the network structure was confirmed by identifying density, distance, community detection, and assortativity and disassortivity. As a result, among the automakers, Hyundai Motor, Kia Motors, and GM Korea were included in the top 15 in 4 indicators of node centrality. In terms of company location, companies located in the Seoul metropolitan area were included in the top 15. In terms of company size, most of the large companies with more than 1,000 employees were included in the top 15 for degree centrality and betweenness centrality. Regarding closeness centrality and eigenvector centrality, most of the companies with 500 or less employees were included in the top 15, except for automakers. In the structure of the network, the density was 0.01390522 and the average distance was 3.422481. As a result of community detection using the fast greedy algorithm, 11 communities were finally derived.

• Journal of Korean Tunnelling and Underground Space Association
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• v.20 no.6
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• pp.1003-1022
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• 2018

In the current work, a series of three-dimensional finite element analyses were carried out to understand the behaviour of a pre-existing single pile to the changes of the tunnel face pressures when a shield TBM tunnel passes underneath the pile. The numerical modelling analysed the results by considering various face pressures (25~100% of the in-situ horizontal stress prior to tunnelling at the tunnel springline). In the numerical modelling, several key issues, such as the pile settlements, the axial pile forces, the shear stresses have been thoroughly analysed for different face pressures. The head settlements of the pile with the maximum face pressure decreased by about 44% compared to corresponding settlement with the minimum face pressure. Furthermore, the maximum axial force of the pile developed with the minimum face pressure. The tunnelling-induced axial pile force at the minimum face pressure was found to be about 21% larger than that with the maximum face pressure. It has been found that the ground settlements and the pile settlements are heavily affected by the face pressures. In addition, the influence of the piles and the ground was analysed by considering characteristics of the soil deformations. Also, the apparent safety factor of the piles are substantially reduced for all the analyses conducted in the current simulation, resulting in severe effects on the adjacent piles. Therefore, the behaviour of the piles, according to change the face pressures, has been extensively examined and analysed by considering the key features in great details.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.10a
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• pp.115-117
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• 1998

생물 발효 공정에 의해 생산된 부탄올 수용액은 농도가 희박하여 농축 공정이 필요하다. 기존의 농축 공정 중 투과증발공정은 공비혼합물이나 비점이 근접한 혼합물등을 분리하는데 에너지가 적게 들고, 분리 효과가 뛰어나며, 조업이 용이하고, 공정이 차지하는 공간이 적다는 장점을 가지고 있다. 산업적으로 관심을 갖는 5 wt% 이하의 부탄올 수용액을 효과적으로 농축시키기 위해 투과증발공정이 사용된다. 현재 투과증발공정에 사용되는 막에는 elastomeric membrane, plasma treated membrane, UV-grafted membrane, polymer blend membrane이 연구 개발되어 사용되고 있는데, 이중 플라즈마 처리방법을 통해 막을 제조 할 경우, 플라즈마 대상 물질의 선택 폭이 넓고, 분리물과 막간의 친화력을 향상 시키기 위해 분리물과 유사한 화학구조를 갖게 할 수 있으며, 형성된 코팅 층이 crosslinking되어 안정성을 갖는 장점이 있다. 따라서 본 연구에서는 플라즈마 처리법을 통해 투과증발막을 제조하고 제조된 막을 부탄올 농축에 사용하여 막의 성능을 조사하였고, 막의 성능과 접촉 각, sorption, heat of mixing간의 상관 관계에 대해 살펴 보았다.

• Proceedings of the Korea Information Processing Society Conference
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• 2019.05a
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• pp.709-710
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• 2019

제안 시스템은 모바일 사용자를 공공 인터넷 환경에서 사용 유형별로 분류 및 관리 가능한 서비스를 제공한다. 비콘을 이용하여 시스템 사용자의 위치와 서비스공간의 근접성을 확인한다. 또한 사용자의 서비스 사용 형태 및 성향에 따라 서비스 제공 장소에서 네트워크에 연결된 사물 인터넷 기기 및 기타 기기에 대한 접근 권한을 미리 정의하고 이를 제공할 수 있다. 본 연구는 이러한 시스템을 제안하고 구현된 결과를 바탕으로 시스템의 기능을 분석한다.