• Archives of Pharmacal Research
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• 제26권9호
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• pp.667-678
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• 2003

We examined the effect of p-substituents in p-substituted cinnamyl methyl ethers and 1-(p-substituted phenyl)allyl methyl ethers with CSI, and confirmed that the CSI reaction of allyl ethers (p-substituted ethers) is a competitive reaction of $S_Ni{\;}and{\;}S_N1$ mechanism according to the stability of the carbocation. And, the only terminal allylic amine was obtained through the migration reaction in thermodynamic reaction condition.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1286-1291
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• 2017

In this paper, we propose an indoor positioning system that makes use of the attenuation model for IEEE 802.11 Channel State Information (CSI) in order to determine its distance from an Access Point (AP) at a fixed position. With the use of CSI, we can mitigate the problems present in the use of Received Signal Strength Indicator (RSSI) data and increase the accuracy of the estimated mobile device's location. For the experiments we performed, we made use of the Intel 5300 Series Network Interface Card (NIC) in order to receive the channel frequency response. The Intel 5300 NIC differs from its counterparts in that it can obtain not only the RSSI but also the CSI between an access point and a mobile device. We can obtain the signal strengths and phases from subcarriers of a system which in turn means making use of this data in the estimation of a mobile device's position.

• 한국전자파학회논문지
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• 제21권3호
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• pp.229-235
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• 2010

고속의 멀티미디어 서비스를 요구하는 추세에 따라 대역폭 효율이 높은 다중 사용자 OFDM(Orthogonal Frequency Division Multiplexing) 시스템에서 자원 할당 방법에 관한 많은 연구가 이루어지고 있다. 본 논문에서는 다중 사용자 OFDM 시스템에서 제한된 자원을 이용하는 자원 할당 방식을 제안한다. 제안된 방식은 기존 알고리즘에 비하여 간략화된 채널 상태 정보(CSI: Channel State Information)를 사용하면서 전체 데이터 전송률을 최대화하는 부반송파 할당 알고리즘이다. 간략화된 CSI 구조를 사용하기 때문에 각 사용자의 정확한 정보를 알 수 없지만, 사용자의 최소 요구 데이터 전송률, 평균 채널 이득 정보를 이용하여 QoS를 만족시킬 수 있는 사용자의 후보를 정하여 부반송파를 할당한다. 결과적으로 기존의 방식에 비해 적은 채널 정보를 사용하여 더 많은 사용자에게 QoS를 만족시킬 수 있다.

• Journal of information and communication convergence engineering
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• 제15권1호
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• pp.14-20
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• 2017

In this paper, we discuss physical layer security techniques in downlink networks, including eavesdroppers. The main objective of using physical layer security is delivering a perfectly secure message from a transmitter to an intended receiver in the presence of passive or active eavesdroppers who are trying to wiretap the information or disturb the network stability. In downlink networks, based on the random feature of channels to terminals, opportunistic user scheduling can be exploited as an additional tool for enhancing physical layer security. We introduce user scheduling strategies and discuss the corresponding performances according to different levels of channel state information (CSI) at the base station (BS). We show that the availability of CSI of eavesdroppers significantly affects not only the beamforming strategy but also the user scheduling. Eventually, we provide intuitive information on the effect of CSI on the secrecy performance by considering three scenarios: perfect, imperfect, and absence of eavesdropper's CSI at the BS.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제7권11호
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• pp.2616-2635
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• 2013

In this paper, we propose an iterative transceiver design in a multi-relay multi-user multiple-input multiple-output (MIMO) system. The design criterion is to minimize sum mean squared error (SMSE) under relay sum power constraint (RSPC) where only local channel state information (CSI)s are available at relays. Local CSI at a relay is defined as the CSI of the channel between BS and the relay in the $1^{st}$ hop link, and the CSI of the channel between the relay and all users in the $2^{nd}$ hop link. Exploiting BS transmitter structure which is concatenated with block diagonalization (BD) precoder, each relay's precoder can be determined using local CSI at the relay. The proposed scheme is based on sequential iteration of two stages; stage 1 determines BS transmitter and relay precoders jointly with SMSE duality, and stage 2 determines user receivers. We verify that the proposed scheme outperforms simple amplify-and-forward (SAF), minimum mean squared error (MMSE) relay, and an existing good scheme of [13] in terms of both SMSE and sum-rate performances.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2005년도 제30회 춘계학술대회
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• pp.93-95
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• 2005

자기공명분광법은 극소의 체적내애서 핵자기공명에 의하여 생화학적 성질들을 고유한 주파수에 따라서 대사물질의 신호를 얻는다. 핵자기공명의 신호는 경사자장 혹은 주파수의 크기를 조절하여 체내의 조직성분을 충분히 포함하여 통과시킨다. 획득되어진 원래 데이터는 TE, TR 등의 물리적 상수값의 변화에 의해서 영향을 받는다. 최근의 펄스 시퀀스는 고해상도 3D CSI 및 SVS가 국소적인 체적내의 대사물질의 변화량을 정성적으로 감지하므로 임상데이터로 활용하기 위한 연구가 더욱 절실하다.

• Journal of Communications and Networks
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• 제18권1호
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• pp.95-104
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• 2016

Massive multiple-input multiple-output (MIMO) is a promising approach for cellular communication due to its energy efficiency and high achievable data rate. These advantages, however, can be realized only when channel state information (CSI) is available at the transmitter. Since there are many antennas, CSI is too large to feed back without compression. To compress CSI, prior work has applied compressive sensing (CS) techniques and the fact that CSI can be sparsified. The adopted sparsifying bases fail, however, to reflect the spatial correlation and channel conditions or to be feasible in practice. In this paper, we propose a new sparsifying basis that reflects the long-term characteristics of the channel, and needs no change as long as the spatial correlation model does not change. We propose a new reconstruction algorithm for CS, and also suggest dimensionality reduction as a compression method. To feed back compressed CSI in practice, we propose a new codebook for the compressed channel quantization assuming no other-cell interference. Numerical results confirm that the proposed channel feedback mechanisms show better performance in point-to-point (single-user) and point-to-multi-point (multi-user) scenarios.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 전기.전자공학 학술대회 논문집(I)
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• pp.791-793
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• 1987

• 한국항해항만학회지
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• 제31권2호
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• pp.151-157
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• 2007

After World Trade Center's Terror in 2001 and promulgating Maritime Transportation Security Act (MTSA, 2002) and Security and Accountability For Every Port Act (SAFE Port Act, 2006) in the United States, most of the attention on security of international transportation including marine carrier and facility has focused increasingly. Inspection stations in foreign seaport terminal including Busan, South Korea, have been installed by Container Security Initiative (CSI) and Customs Trade Partnership against Terrorism (C-TPAT). The inspection station, however, may directly and indirectly affect delay of truck turnaround time in the seaport, especially high and severe level of security. This paper was analysed a risk for the additional average delay of truck turnaround time incurring by the inspection station under the all level of security, C-TPAT and CSI. As a result of this risk analysis, the higher weighted inspection time based on raising security level, the less number of trucks to be inspected, which will derive high delay in the inspection station.

• 한국항해항만학회지
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• 제38권3호
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• pp.317-325
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• 2014

우리나라 정부는 글로벌 보안 추세와 전쟁 및 테러리즘에 대처하기 위해 컨테이너 보안조치(CSI, 24시간 규칙 포함), 종합인증 우수업체(AEO) 등 다양한 보안 제도 및 보안 조치를 도입했다. 하지만 수출입 과정의 다양한 구성원들은 CSI, 24시간 규칙, AEO의 목적과 기능에 여전히 부정적이다. 이것은 보안 리스크를 수출입 과정의 장애나 방해 요인으로 여기고 있기 때문이다. 따라서 본 연구의 목적은 이러한 리스크를 규명, 측정, 평가하고 적절한 관리 방안을 제시함에 있다. 이를 위한 리스크규명과 리스크관리에 따른 성과 측정을 위해 선행연구 및 현장조사를 바탕으로 설문조사를 진행했다. 설문조사를 통해 대상 리스크를 상대적인 값을 구분하여 Key Risk, Major Risk, Minor Risk로 나눌 수 있었으며 각 리스크를 대상으로 분산분석을 실시하여 집단별 관리정도의 차이를 알아낼 수 있었다. 마지막으로 회귀분석을 통해 리스크관리 정도별 물류성과 검증을 실시하여 CSI 리스크관리가 물류 재무적 성과에 유의미한 영향을 미치며, CSI 리스크관리와 AEO 인증 리스크관리는 물류 서비스 성과에 유의미한 영향을 미치는 것을 알아낼 수 있었다.