• 한국항해항만학회지
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• 제32권3호
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• pp.251-255
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• 2008

컨테이너 크레인은 강풍으로부터 보호를 받기 위한 차폐물이 없는 곳에 존재하기 때문에 이상 기후 조건에 취약성이 있는 구조물이다. 본 연구에서는 풍향변화에 따라 컨테이너 크레인에 작용되는 풍하중을 분석하기 위하여 수행되었다. 사용된 모델은 61톤 급 컨테이너 크레인으로 현재 항만시설에 많이 사용되는 모델이다. 유동장은 원통으로 모델링하였으며, 직경 500m, 높이 200m로 설정하였다. 본 연구에서는 건축물 하중기준의 풍하중 설계기준에 따라 풍하중을 적용하였으며 풍향에 따른 영향을 분석하기 위해서 유동장을 $10^{\circ}$ 간격으로 분할하였다. 이를 바탕으로 CFX-10을 사용하여 전산유동해석을 수행하고 이를 통하여 얻어진 결과와 풍력실험 결과를 비교 연구함으로써, 컨테이너 크레인의 구조설계에 필요한 풍하중을 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권8호
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• pp.3826-3851
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• 2016

With traditional data storage solutions becoming too expensive and cumbersome to support Big Data processing, enterprises are now starting to outsource their data requirements to third parties, such as cloud service providers. However, this outsourced initiative introduces a number of security and privacy concerns. In this paper, homomorphic encryption is suggested as a mechanism to protect the confidentiality and privacy of outsourced data, while at the same time allowing third parties to perform computation on encrypted data. This paper also discusses the challenges of Big Data processing protection and highlights its differences from traditional data protection. Existing works on homomorphic encryption are technically reviewed and compared in terms of their encryption scheme, homomorphism classification, algorithm design, noise management, and security assumption. Finally, this paper discusses the current implementation, challenges, and future direction towards a practical homomorphic encryption scheme for securing outsourced Big Data computation.

• 소성∙가공
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• 제19권3호
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• pp.185-190
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• 2010

Application of CAE analyses are wide spread in shaping processes and structural safety verification of plastic products. The importance of CAE analysis and its contributions are getting increase since the processibility and structural safety of product can be predicted. CAE analysis for complex shaped product need a lot of time for modeling and computation compare with simpler one. Therefore careful simulation modeling is required for complex shaped product. Structural analysis for plastic door handle of automobile has been performed and structural safety has been investigated for various load directions and modeling cases. Large stress occurred at the hinge in handle regardless of load direction and modeling case. Consequently hinge is considered structurally very weak among the parts in plastic door handle. It is concluded that simple modeling rather than total modeling with adequate boundary condition equivalent to real situation gives reasonable computational results with saving modeling effort and computation time.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 1999년도 추계종합학술대회 논문집
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• pp.1097-1100
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• 1999

Due to the significant computation of full search in motion estimation, extensive research in fast motion estimation algorithms has been carried out. However, most of the algorithms have the degradation in predicted images compared with the full search algorithm. To reduce an amount of significant computation while keeping the same prediction quality of the full search, we propose a fast block-matching algorithm based on gradient magnitude of reference block without any degradation of predicted image. By using Taylor series expansion, we show that the block matching errors between reference block and candidate block are proportional to the gradient magnitude of matching block. With the derived result, we propose fast full search algorithm with adaptively determined scan direction in the block matching. Experimentally, our proposed algorithm is very efficient in terms of computational speedup and has the smallest computation among all the conventional full search algorithms. Therefore, our algorithm is useful in VLSI implementation of video encoder requiring real-time application.

• 조명전기설비학회논문지
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• 제28권11호
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• pp.93-99
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• 2014

The method of moments is applied to numerically compute the electrostatic capacitance of a parallel-plate rectangular capacitor of finite area. Each plate is discretized into 900 patches per unit area to ensure a high accuracy of computation. To further enhance computational results, the impedance matrix elements are additionally evaluated in the case that the observation patch is located above or below the source patch in the vertical direction. To examine the fringing effect at the edges of the capacitor, the normalized capacitances are computed as a function of separation distance. After these results have been verified by Palmer's formula, this method is extended to the computation of capacitances between two different size plates.

• Coupled systems mechanics
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• 제8권2호
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• pp.111-127
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• 2019

In this paper, we present a 2D multi-scale coupling computation procedure for localized failure. When modeling the behavior of a structure by a multi-scale method, the macro-scale is used to describe the homogenized response of the structure, and the micro-scale to describe the details of the behavior on the smaller scale of the material where some inelastic mechanisms, like damage or plasticity, can be defined. The micro-scale mesh is defined for each multi-scale element in a way to fit entirely inside it. The two scales are coupled by imposing the constraint on the displacement field over their interface. An embedded discontinuity is implemented in the macro-scale element to capture the softening behavior happening on the micro-scale. The computation is performed using the operator split solution procedure on both scales.

• 정보처리학회논문지D
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• 제15D권3호
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• pp.399-410
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• 2008

본 논문은 기존 위치기반 서비스에서 최근접질의 및 한 지점에서의 방향성분을 고려한 최근접질의의 단점을 해소하고자 가중치 벡터합을 이용하는 새로운 검색방법을 제안한다. 검색반경으로 1차 필터링된 영역에서, 2차 필터링을 위해 이용자의 이동방향, 관심방향 및 검색각도를 조합한 방향정보를 이용한다. 이동방향은 일정구간내 존재하는 벡터들의 가중치 합으로 계산하며, 검색각도를 $0{\sim}360^{\circ}$까지 세분화하여 검색방향에 대한 범위를 조절 하도록 한다. 본 검색방법에 사용되는 데이터는 촬영위치가 기록된 정지영상 및 동영상, 업체나 관광지의 위치정보와 함께 소비자에게 제공되는 텍스트, 웹, 영상 등 각종 미디어 형태의 데이터가 될 수 있다. 제안하는 방법은 이동 중인 이용자가 현 위치를 기준으로 일정 반경 내에 있으면서 유사방향에 부합하는 미디어만을 검색하도록 함으로써, 이미 지났거나 혹은 관련 없는 방향의 미디어를 배제한 검색결과를 제공하기 때문에 기존의 위치만을 고려한 검색방법에 비해 보다 정확한 검색을 보장할 수 있으며, 방향성을 고려한 기존 최근접질의 에 비해서도 보다 유연하고 포괄적인 검색결과를 보장한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제13권10호
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• pp.4849-4864
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• 2019

Modern applications such as augmented reality, connected vehicles, video streaming and gaming have stringent requirements on latency, bandwidth and computation resources. The explosion in data generation by mobile devices has further exacerbated the situation. Mobile Edge Computing (MEC) is a recent addition to the edge computing paradigm that amalgamates the cloud computing capabilities with cellular communications. The concept of MEC is to relocate the cloud capabilities to the edge of the network for yielding ultra-low latency, high computation, high bandwidth, low burden on the core network, enhanced quality of experience (QoE), and efficient resource utilization. In this paper, we provide a comprehensive overview on different traits of MEC including its use cases, architecture, computation offloading, security, economic aspects, research challenges, and potential future directions.

• 설비공학논문집
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• 제21권5호
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• pp.282-290
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• 2009

A ceramic monolith heat exchanger is studied to find the performance of heat transfer and pressure drop by numerical computation and $\xi$-NTU method. The numerical computation was performed throughout the domain including fluid region in exhaust gas-side rectangular ducts, ceramic core and fluid region in air-side rectangular duct with the air and exhaust in cross flow direction. In addition, the heat exchanger was also analyzed to estimate the performance by conventional $\xi$-NTU method with several Nusselt number correlations for flow in rectangular duct from literature. By comparisons of both performances by the numerical computation and the $\xi$-NTU method, the effectiveness by $\xi$-NTU method was closest to the result by numerical computation within a relative error of 2.14% when Stephan's Nusselt number correlation was adopted to the $\xi$-NTU method among the several correlations.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2006년도 춘계학술대회 및 창립 30주년 심포지엄(논문집)
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• pp.349-354
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• 2006

본 연구는 풍하중이 컨테이너 크레인에 작용할 때, 풍향에 따라서 컨테이너 크레인의 유동장을 분석하였다. 본 연구를 위해 사용된 모델은 50ton급 컨테이너 크레인으로 현재 항만시설에 가장 많이 사용되는 모델이다. 유동장은 원통으로 모델링하였으며, 직경, 300m 높이 200m로 설정하였다. 본 연구는 멱급수를 적용하여 풍속 50m/s의 설계 기준에서 고도에 따라 풍속을 고려하였다. 또한 풍향은 $0^{\circ}{\sim}180^{\circ}$ 를 $30^{\circ}$ 간격으로 적용하였으며, CFX-10을 사용하여 전산유동해석을 수행하였다. 본 연구에서는 풍향에 따른 풍압력을 분석하였으며, 향후 유동 연성 해석을 통한 컨테이너 크레인의 구조 안정성 평가를 할 것이다.