• 지구물리
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• 제7권2호
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• pp.151-155
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• 2004

도시 수해 문제를 해결하기 위해서는 충분한 펌핑 시스템과 하천 유하능력을 확보하여야 하나 하천의 유하 능력을 넘어서는 유출이 발생하는 경우 각 소유역 별로 이들 유량을 일시적으로 저류 할 수 있는 유수체계의 설치가 필요할 것이다 그러나 이러한 유수체계의 설치에도 불구하고 강우 분포의 변화 및 유량의 이동 지체에 따라 오히려 첨두 유량이 증가하는 문제를 발생시킬 수도 있으므로 상류와 하류에 위치한 각 유수지의 저류량과 유출 펌핑량 간의 시간문제 등 상호 관련성을 고려한 유수체계의 설치 모형이 필요하므로 IDP(Incremental Dynamic Programming) 기법을 적용하여 강우 분포에 따른 유수지 상호간의 영향을 고려한 설계 모형을 제시하였다

• 전기전자학회논문지
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• 제23권3호
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• pp.1046-1053
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• 2019

멀티채널 단일 종단(single-ended) 환경에서 채널 사이의 상호인덕턴스 및 상호캐패시턴스에 의한 원단누화 현상(FEXT)은 결정적으로 채널의 대역폭 감소를 일으킨다. 원단누화에 의해 누화-유발 지터(CIJ)와 누화-유발 글리치(CIG)가 생기며 이들은 각각 타이밍 마진 감소와 전압 마진 감소를 일으킨다. 따라서 아이 오프닝 증가와 높은 데이터 전송속도를 얻기 위해서는 원단누화 현상을 보상해야 한다. 원단누화 보상은 송신단에서 타이밍 조절 또는 파형 변형을 통해 보상할 수 있다. 또한, 수신단에서 고역-필터를 사용하여 유사 원단누화 잡음을 만들어 보상하는 방법도 있다. 본 논문에서는 원단누화 보상의 최근 기술 동향을 소개하며, 이들의 장점과 단점을 논의한다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제12권8호
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• pp.3589-3605
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• 2018

In this paper, we investigate an individual channel estimation problem for multiple-input multiple-output (MIMO) two-way amplify-and-forward (AF) relay networks. To avoid self-interference during the estimation of the individual MIMO channels, a novel blind interference cancellation (BIC) approach is proposed based on an orthogonal preceding framework, where a pair of orthogonal precoding matrices is utilized at the source nodes. By designing an optimal decoding scheme, we propose to decompose the bidirectional transmission into a pair of unidirectional transmissions. Unlike most existing approaches, we make the practical assumption that the nonreciprocal MIMO channel and the mutual interference of multiple antennas are both taken into consideration. Under the precoding framework, we employ an orthogonal superimposed training strategy to obtain the individual MIMO channels. However, the AF strategy causes the noise at the terminal to be the sum of the local noise and the relay-propagated noise. To remove the relay-propagated noise during the estimation of the second-hop channel, a partial noise-nulling method is designed. We also derive a closed-form expression for the total mean square error (MSE) of the MIMO channel from which we compute the optimal power allocation. The simulation results demonstrate that the analytical and simulated curves match fully.

• ETRI Journal
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• 제26권6호
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• pp.605-614
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• 2004

In this paper, we investigate array calibration algorithms to derive a further improved version for correcting antenna array errors and RF transceiver errors in CDMA smart antenna systems. The structure of a multi-channel RF transceiver with a digital calibration apparatus and its calibration techniques are presented, where we propose a new RF receiver calibration scheme to minimize interference of the calibration signal on the user signals. The calibration signal is injected into a multi-channel receiver through a calibration signal injector whose array response vector is controlled in order to have a low correlation with the antenna response vector of the receive signals. We suggest a model-based antenna array calibration to remove the antenna array errors including mutual coupling errors or to predict the element patterns from the array manifold measured at a small number of angles. Computer simulations and experiment results are shown to verify the calibration algorithms.

• 대한한의학원전학회지
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• 제20권4호
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• pp.151-169
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• 2007

The "Tai Su(太素)" which was published by Yang Shang Shan(楊上善) during the Tang(唐) dynasty does not follow complicating hand down procedures allowing it to be preserved in a relatively satisfactory state, and the book is evaluated as a major article in the study of the "Yellow Emperor's Internal Classic(黃帝內經)" in the modern age. The book of "Tai Su explanation of channel diseases(太素 經脈病解)" offers the detailed description of disease symptoms found in the book of "Miraculous Pivot channels(靈樞 經脈)", and Yang Shang Shan(楊上善) provided relatively complete explanations from the perspective of the wane and wax of shadow and sunshine powers(陰陽消長). The present writing was projected to acknowledge the relationship between the books of "Tai Su explanation of channel diseases(太素 經脈病解)" and "Miraculous Pivot channels(靈樞 經脈)" and substantially attempted to understand the original text of the "Tai Su(太素)" by adopting the perspectives of Yang Shang Shan(楊上善) in explaining the disease symptoms as he attempted in the book of "Miraculous Pivot channels(靈樞 經脈)". Total 50 disease symptoms were explained in the book of "Tai Su explanation of channel diseases(太素 經脈病解)", and 33 of them are common to the symptoms described in the book of "Miraculous Pivot channels(靈樞 經脈)" by taking up about 66% of the book. The monthly attachment(月別配屬) of three shadow and three sunshine power(三陰三陽), which is described in the book of "Tai Su explanation of channel diseases(太素 經脈病解)" provides an important clue in understanding the exterior and interior(表裏) relationship, and the crucial perspective lies on the mutual intensity change of shadow and sunshine powers. Therefore, the monthly attachment of three shadow and three sunshine power provided by the present article helps to understand the meaning of the three shadow and three sunshine power along with the time attachment(時間配屬) described in the other chapter of the "Yellow Emperor's Internal Classic(黃帝內經)". In the method of explaining pathogenesis, the explanation was made by understanding the perspective of mutual intensity change of shadow and sunshine powers, and exterior and interior relationship along with the channel Path(經脈流注) have been used simultaneously. In the comment of the main article, Yang Shang Shan(楊上善) stated the channels of hands and feet(手足經脈) as the scope of the three shadow and three sunshine power, but the symptoms and signs are mainly focused on the channels of feet as in the book of "Miraculous Pivot channels(靈樞 經脈)".

• 한국전자파학회논문지
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• 제15권8호
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• pp.759-764
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• 2004

본 논문에서는 3D 광선추적법에 기반한 전파 예측 모델을 이용하여 MIMO 채널 특성을 해석적으로 분석하는 방법을 제시한다. 경로들의 위상차를 고려하여 채널간 discrete spatial correlation을 계산하고 이를 이용하여 젠센 부등식을 이용해 평균 MIMO채널 용량의 최대치를 추정한다. 본 해석 모델은 측정을 통한 통계적 접근이나 Monte-Carlo 시뮬레이션을 통한 확률적 접근을 하지 않는 결정적인 모델이므로 시간과 비용측면에서 큰 효율을 가진다. 또한 전파 이론에 기초한 방법이므로 채널 용량에 영향을 미칠 수 있는 안테나 패턴이나 편파, 상호간섭, 안테나 구조 등의 파라미터를 정량적으로 분석 할 수 있는 장점이 있다. 본 모델은 MIMO 시스템에 적합한 안테나 구조 등의 개발에 이용될 수 있을 것이다.

• 유통과학연구
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• 제19권1호
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• pp.105-113
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• 2021

Purpose: The rural market in India provides tremendous scope for FMCG consumer healthcare companies to market their products because of a significant increase of rural purchasing power. Many empirical studies in this area highlight the challenges and opportunities for marketers in the FMCG space. Research articles are not in abundance to understand intermediaries' expectations in the supply chain specific to consumer healthcare products. The existing literature did not significantly address the challenges of channel partners in the rural market. The present study aims to determine the retailer expectations from manufacturers and channel members' mutual expectations in the FMCG distribution channel. Research design and Methodology: The present study adopted a qualitative research methodology. Fifty respondents from each level of distribution channel such as super-stockist, distributors and retailers in central India were identified and an interview method was adopted to collect the data. Results: Nineteen factors were identified to influence the intermediaries for involvement in the business with any FMCG brand. Factors like Profit margin, reverse logistics, credit terms, return on investment, timely payments were crucial for managing the expectations of all intermediaries. This study provides academic as well as practical implications in terms of enabling the industry to align its channel management strategies accordingly.

• 한국정보통신학회논문지
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• 제8권6호
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• pp.1068-1075
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• 2004

2.4㎓ 대역 무선통신망을 통해 서비스되는 WLAN과 Bluetooth시스템은 서로 동일한 환경 하에서 상호 보완적인 서비스를 제공하고 있다. 이러한 두 시스템의 상호 패킷이 시간과 가우시안 거리의 불확실성에 존재할 경우 시스템간에 충돌이 발생하게 된다. 따라서 본 논문에서는 두 시스템간의 상호 공존의 방법을 도모하기 위해 상호 간섭의 영향을 분석하고자한다. 반송파 주파수 오프셋에 따른 신호대 잡음간섭신호에 의한 심볼 오차확률의 분석을 통해 두 시스템간의 간섭영향을 분석하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제5권9호
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• pp.1684-1697
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• 2011

We show that two protocols for RFID mutual authentication in pervasive computing environments, recently proposed by Kang et al, are vulnerable to several attacks. First, we show these protocols do not preserve the privacy of users' location. Once a tag is authenticated successfully, we show several scenarios where legitimate or illegitimate readers can trace the location of that tag without any further information about the tag's identifier or initial private key. Second, since the communication between readers and the database takes place over an insecure communication channel and in the plaintext form, we show scenarios where a compromised tag can gain access to confidential information that the tag is not supposed get access to. Finally, we show that these protocols are also vulnerable to the replay and denial-of-service attacks. While some of these attacks are due to simple flaws and can be easily fixed, others are more fundamental and are due to relaxing widely accepted assumptions in the literature. We examine this issue, apply countermeasures, and re-evaluate the protocols overhead after taking these countermeasures into account and compare them to other work in the literature.

• Journal of electromagnetic engineering and science
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• 제3권2호
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• pp.99-103
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• 2003

For mobile multimedia systems that equip transmit diversity for a forward channel, it is well known that the Tx diversity technique is appropriate for high rate mobile multimedia communications. In this paper, we propose a STTD (Space Time Transmit Diversity) receiver, which incorporates the design of the Tx diversity receiver without the mutual interference of antenna by using a CCI cancellation technique. The new STTD receiver is simulated and its performance is analyzed in a DS-CDMA/QPSK. Adopting the proposed STTD receiver at $10^{-2}$TEX>∼$10^{-4}$TEX> in bit error rate, SNR of 0.5 ㏈∼2 ㏈ performance improvement in AWGN and Rayleigh fading environments has been achieved.