• Journal of the Korea Institute of Information Security & Cryptology
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• v.21 no.3
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• pp.11-25
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• 2011

The Miller algorithm is employed in the typical pairing computation such as Weil, Tate and Ate for implementing ID based cryptosystem. By analyzing the Mrabet's attack that is one of fault attacks against the Miller algorithm, this paper presents au efficient fault attack in Affine coordinate system, it is the most basic coordinates for construction of elliptic curve. The proposed attack is the effective model of a count check fault attack, it is verified to work well by practical fault injection experiments and can omit the probabilistic analysis that is required in the previous counter fault model.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.1-8
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• 2003

Scheduling technology is one of the most important elements required to support the Quality of service (QoS) in the Internet and a lot of scheduling algorithms have been developed. However, most of these algorithms ire not flexible to distribute the excess bandwidth. In order to provide flexibility for distributing the excess bandwidth, we proposed excess bandwidth fair queueing (EBFQ) algorithm with relatively low complexity. In this paper, we propose the new extension to this EBFQ algorithm for the hierarchical fair queueing system. This extension can be naturally applied to the existing hierarchical algorithm and simultaneously provide the same level of fairness. Through the simulation and analysis, we verify it.

• 기계와재료
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• v.22 no.1
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• pp.6-13
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• 2010

스마트 폰을 비롯한 고성능/다기능/소형 모바일 기기를 중심으로 고밀도/다층/차세대 FPCB의 적용이 지속적으로 확대되고 있다. 이러한 고부가 FPCB의 생산 공정에서 드릴링, 절단, 트리밍, 리페어 등의 고정에 적용하기 위한 UV 레이저 기반 초정밀/초고속 드릴링 및 복합/유연 공정 및 장비 기술의 개발을 목표로 하는 청정제조기반 산업원천기술개발 과제가 한국기계연구원의 총괄로 2009년 6월 출범하였다. 본 고에서는 본 과제에 대해 간략하게 설명하고, 관련 국내외 시장의 최신 동향을 살펴보고자 한다.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.4
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• pp.527-535
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• 2019

Hanger in a rail-launched missile protrudes in general and causes to increase significant drag force. One method to avoid the significant increase of drag force is to apply fairings on the hanger. In this paper, sloping shaped fairing parameters of height, width, and length are optimized to minimize the drag force under subsonic speed region by examining three configurations of fairings : front-fairing only, rear-faring only, and the both front and rear fairing. We use Latin Hypercube Sampling method to determine the experimental points, and computational fluid dynamics with incompressible RANS solver was applied to acquire the data at sampling points. Then, we construct a meta model by kriging method. We find the best choice among three configurations examined : both front and rear fairing reduce the drag force by 63 % without the constraint of fairing mass, and front fairing reduced the drag force by 52 % with the constraint of hanger mass.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.192.1-192.1
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• 2012

영상레이더 (SAR: Synthetic Aperture Radar) 혹은 통신 안테나/탑재체를 장착한 위성은 원하는 주파수 대역의 운용을 위해 대형 안테나 구조물 장착이 필수적이다. 이러한 대형 구조물은 일체형으로 제작되어 위성체에 접속되었을 때, 요구 무게 및 점유하는 부피가 매우 큰 특징을 지닌다. 따라서, 대형 안테나 구조물의 중량으로 인해 발사비 증가가 불가피하며, 페어링 내부의 허용된 공간에 안테나 크기는 큰 제약적 요인이 된다. 그리고, 전개식이어도, 전개후 질량 관성이 큰 구조물이 된다. 위성체의 발사 비용과 직결되는 안테나의 경량화를 위한 많은 기술이 연구되고 있다. 특히, 접이식 팽창형 안테나는 반사체의 유연한 메쉬 구조 및 경량 지지구조물로 안테나의 무게를 줄이고 수납 효율을 향상시킨다. 또한, 전개 후 안테나의 목적한 기능을 충분히 보장함과 동시에 질량 관성이 작은 구조물에 의한 위성의 기동성을 극대화할 수 있다. 국내에서도 전천후 지상관측감시 및 통신 안테나의 필요성 증대에 따라 초경량 전개형 안테나 개발의 필요성이 크게 대두되고 있으나, 현재까지는 관련 기술개발 사례가 전무한 실정으로 국내 독자적 기술 확보가 시급한 실정이다.

• KIEAE Journal
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• v.17 no.3
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• pp.119-124
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• 2017

Purpose: Groundwater heat pump (GWHP) system has high coefficient of performance than conventional air-source heat pump system and closed-loop type geothermal system. However, there is problem in long-term operation that groundwater raise at the diffusion well and reduced at the supply well. Therefore, it is necessary to accurately predict the groundwater flow, groundwater movement and control the groundwater level in the wells. In this research, in consideration of hydrogeological characteristic, groundwater level and groundwater movement were conducted analysis in order to develop the optimal design method of the two-well system using the pairing pipe. Method: For the optimum design of the two-well system, this research focused on the design method of the pairing pipe in the simulation model. Especially, in order to control the groundwater level in wells, pairing pipe between the supply well and diffusion well was developed and the groundwater level during the system operation was analyzed by the numerical simulation. Result: As the result of simulation, the groundwater level increased to -2.65m even in the condition of low hydraulic conductivity and high pumping flow rate. Consequently, it was found that the developed system can be operated stably.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.96-101
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• 2015

This paper describes a design and implementation of the NFC bridge chip which performs interface between kinds of devices and mobile phones including NFC controller through NFC communication. The NFC bridge chip consists of the digital part and the analog part which are based on NFC Forum standard. Therefore the chip treats RF signals and then transforms the signal to digital data, so it can interface kinds of devices with the digital data. Especially the chip is able to detect RF signals and then wake up the host processor of a device. The wakeup function dramatically decreases the power consumption of the device. The carrier frequency is 13.56MHz, and the data rate is up to 424kbps. The chip has been fabricated with SMIC 180nm mixed-mode technology. Additionally an NFC bridge chip application to the blood glucose measurement system is described for an application example.

• Proceedings of the Korean Information Science Society Conference
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• 2010.06d
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• pp.95-100
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• 2010

높은 이동성 및 휴대성을 갖는 모바일 디바이스의 기술적 발전은 사용자로 하여금 보다 높은 수준의 통합된 편의 기능 제공이 요구되고 있다. 이러한 예로 기존 물리적 지갑에 보관하던 플라스틱 신용카드, 멤버쉽 카드, 신분증 등의 개인정보를 모바일 디바이스 안에 저장 관리하는 모바일 지갑 서비스가 현실화되고 있다. 모바일 지갑을 통한 상거래 서비스를 이용할 시 디바이스에 저장된 각종 개인정보가 근거리 무선통신 기술을 통해 다른 모바일 기기나 지불서버에 전달되는 데, 이 무선전송 구간은 근원적으로 많은 보안 취약점을 갖고 있다. 따라서 본 논문에서는 모바일 지갑 응용 서비스에 모바일 기기간 안전한 키 설정 시 공개키 인증서를 활용하지 않고 두 기기간 공유키 검증을 할 수 있는 세션 키 검증 기술들을 분석하고, 해당기술들을 구현하여 모바일 지갑 결제 테스트베드에 포팅한 실험 결과를 통한 성능분석 결과를 제시한다. 본 성능평가를 통해 향후 다양한 모바일 기기 특성에 따른 최적의 세션 키 공유 키 검증 방법 선택 시 유용한 근거자료로 활용할 수 있을 것으로 기대된다.

• Aerospace Engineering and Technology
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• v.7 no.2
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• pp.117-122
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• 2008

Acoustic test was performed to verify the ability of KSLV-I PLF acoustic protection system (Acoustic blanket) to reduce the acoustic load. The test results showed that the acoustic protection system has +3 dB safety margin compared with design requirement. This paper also illustrates the increase of insertion loss by the acoustic protection system by comparing that of the bare PLF structure.

• Aerospace Engineering and Technology
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• v.6 no.2
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• pp.60-65
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• 2007

Acoustic chamber was developed for verifying the performance of a satellite under the launch condition on the Space environment test department. As the size of a satellite is increased the extension of existing facility is required. This paper encompasses the following items; redesign of components in acoustic chamber, product procedures of them and review of the test for the components of satellite in the upgraded acoustic chamber.