• 한국산업융합학회 논문집
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• 제23권5호
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• pp.727-733
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• 2020

Recently, reciprocating cryogenic pumps are mainly developed for small-and-mid sized fuel supply systems. Centrifugal type pumps are not actively developed. Most cryogenic submerged pumps are imported. For transportation, cryogenic liquefied natural gas requires the liquid pump technology that can works in extreme evironments. In order to transport liquefied natural gas, it is necessary to apply pump technology. This is the fundamental research for developing the submerged pump technology applicable to the transportation and storage system equipment of cryogenic liquefied system. It tries to secure basic design materials through reverse-engineering in the cryogenic submerged pump development. Regarding materials, STS-304 and STS-431 which are stainless materials widely used in the cryogenic area are applied. Aluminum alloy is applied to impeller and upper manifolder and the pump rotates at the high speed of 6,000rpm.

• 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.

• 한국소음진동공학회논문집
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• 제13권11호
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• pp.852-859
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• 2003

In order to meet the growing demands for higher storage density as well as lower noise level, the spindles in hard disk drives are to be supported by hydrodynamic bearings in place of conventional ball-type ones. However, the existing models are inappropriate to apply to accurate prediction of vibration characteristics because the HDD spindle tends to take quite a complex shape to secure its performance and cost-effectiveness. In this context, this paper treats analysis of free and forced vibrations of such-designed HDD spindles based on more sophisticated models and validations via experiments. Remarkably, to this end all the components in the system are modeled as elastic adopting the finite element method.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.1000-1003
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• 2002

For high density optical storage, there should be a high NA objective lens and a shorter wavelength laser diode. To secure the disc tilt margin related to the coma aberration, moreover, it's difficult to apply the tilt compensation mechanism into the portable PC. In this paper, we proposed the 3-axis asymmetry pickup actuator with high efficiency symmetric magnetic circuit, which consisted of the top cover type inner yoke for high magnetic flux density, the coil stack unit for the 3-axis independent operation and vertically polarized magnets. This newly suggested actuator features DVD-RAM recording, we achieved the high focus & track AC sensitivity and the greatly stabilized system.

• 한국멀티미디어학회:학술대회논문집
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• 한국멀티미디어학회 2012년도 춘계학술발표대회논문집
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• pp.343-344
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• 2012

With the increase of sensitive data and their secure transmission and storage, the use of encryption techniques has become widespread. The performance of encoding majorly depends on the computational time, so a system with less computational time suits more appropriate as compared to its contrary part. Double Random Phase Encoding (DRPE) is an algorithm with many sub functions which consumes more time when executed serially; the computation time can be significantly reduced by implementing important functions in a parallel fashion on Graphics Processing Unit (GPU). Computing convolution using Fast Fourier transform in DRPE is the most important part of the algorithm and it is shown in the paper that by performing this portion in GPU reduced the execution time of the process by substantial amount and can be compared with MATALB for performance analysis. NVIDIA graphic card GeForce 310 is used with CUDA C as a programming language.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2007년도 춘계학술발표대회
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• pp.103-106
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• 2007

디지털 콘텐츠가 나타나면서 시대별 유통 방법이 제안되고 발전돼왔다. 초창기 저용량의 디지털 콘텐츠에서 현재 대용량의 DVD급 화질의 콘텐츠가 유통되고 있다. 아날로그 콘텐츠와는 달리 디지털 콘텐츠가 불법복제 되면 콘텐츠의 저작권자는 더욱 큰 물질적인 손해를 입게 된다. 그래서 DRM(Digital Rights Management)기술이 디지털 콘텐츠에 적용되어 콘텐츠를 보호하게 되었다. 하지만 표준화되지 못한 DRM 기술은 여러개의 전용 클라이언트 프로그램이 필요하게 되었고, 콘텐츠의 유통흐름을 원활하게 못하고 있는 실정이다. 제안된 시스템은 디지털 콘텐츠와 플레이어의 일체화된 구조로서 디지털콘텐츠를 1차 패키징 하고, 플레이어의 Secure Storage에 2차 패키징 하여 콘텐츠와 플레이어가 하나의 파일로 배포되어진다. 2차 패키징 된 결과물은 PackPlayer라 명칭한다. 콘텐츠와 플레이어가 하나의 파일로 배포되어지면 사용자가 쉽게 콘텐츠를 볼 수 있으며, 원활한 콘텐츠의 유통과 다양한 상품서비스를 가능하게 해줄 수 있을 것이다.

• 한국컴퓨터정보학회논문지
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• 제12권6호
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• pp.193-200
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• 2007

기존의 바코드(Bar code) 시스템에 비하여 RFID(Radio Frequency Identification) 시스템은 저장능력이 뛰어나고 사물에 비접촉성을 갖는 장점이 있다. 그러나 RF(Radio Frequency) 신호를 이용하여 통신을 하기 때문에 전송되는 정보를 누구나 손쉽게 수신할 수 있어 시스템 보안과 개인의 프라이버시를 침해하는 문제점을 갖고 있다. 본 논문에서는 도청, 재전송, 스푸핑(Spoofing) 그리고 위치추적과 같은 공격에 안전하며 리더(Reader)와 태그(Tag) 간에 상호 인증을 효율적으로 할 수 있는 RFID 시스템을 제안한다. 제안한 시스템은 앞으로 유비쿼터스(Ubiquitous) 환경에서 다양한 분야에 활용될 수 있을 것이다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문초록집
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• pp.397.1-397
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• 2002

For high density optical storage, there should be a high NA objective lens and a shorter wavelength laser diode. To secure the disc tilt margin related to the coma aberration, moreover, it's difficult to apply the tilt compensation mechanism into the portable PC. In this paper, we proposed the 3-axis asymmetry pickup actuator with high efficiency symmetric magnetic circuit, which consisted of the top cover type inner yoke for high magnetic flux density, the coil stack unit for the 3-axis independent operation and vertically polarized magnets. (omitted)

• 한국식품조리과학회지
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• 제18권3호
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• pp.309-318
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• 2002

The purposes of this study were to estimate the microbial and physicochemical quality of vegetable dishes without heat treatment such as sengchae, a traditional Korean vegetable dish, and to suggest a safer method of preparation. Platycodon sengchae and vegetable salad were monitored from the ingredient to final product before serving while storing at different temperature (4, 10$^{\circ}C$) and period (1, 2, 4, 7 days) at foodservice establishments. The results showed that the storage temperature pH, Aw, moisture content, and microbial loads are the important factors affecting the quality of vegetable dishes without heat treatment, and a thorough hygienic management from the purchase to the preparation of the dishes is needed to secure the quality of prepared foods in the foodservice establishments.

• 한국정밀공학회지
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• 제23권4호
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• pp.162-167
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• 2006

Hot embossing lithography(HEL) has the production advantage of comparatively few process step, simple operation, a relatively low cost for embossing tools(Si), and high replication accuracy for small features. In this paper, we considered the nano-molding characteristic according to molding parameters(temperature, pressure, times, etc) and induced a optimal molding condition using HEL. High precision nano-patter master with various shapes were designed and manufactured using the DRIE(Deep Reactive ion Etching), LPCVD(Low Pressure Chemical Vapor Deposition) and thermal oxidation process, and we investigated the molding characteristic of DVD and Blu-ray nickel stamp. We induced flow behaviors of polymer, rheology by shapes and sizes of the pattern through various molding experiments. Finally, with achieving nano-structure molding with high aspect ratio, we will secure a basic technology about the molding of large-area nano-pattern media.