• 정보처리학회논문지C
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• 제13C권6호
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• pp.749-756
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• 2006

단일 안테나를 사용하는 사용자들 사이의 협력통신은 무선 매체의 전송 특성이나 경로 손실을 이용하여 안테나의 숫자를 증가하지 않고도 다중 안테나 시스템의 강력한 장점을 얻을 수 있다. 본 논문에서는 ML(Maximum Likelihood) 검파기의 구조를 간단하게 할 뿐만 아니라 에러확률을 최소화 할 수 있는 전송신호 증폭인자의 최적화를 통해 전파환경의 변화에 순응하는 협력통신의 방법에 대해 제안한다. 제안하는 협력통신에 대해 수학적인 해석에 의한 BER(Bit Error Ratio) 표현을 유도할 뿐만 아니라 모의 실험 결과를 통해 그 성능을 비교한다. 다양한 수학적 계산의 결과를 통해 주파수 비선택적 Rayleigh 페이딩 채널에 AWGN(Additive White Gaussian Noise)이 합쳐진 채널 환경에서 실험한 결과 협력통신이 비 협력통신 보다 현저히 성능이 좋음을 알 수 있다.

• 사상체질의학회지
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• 제24권2호
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• pp.47-53
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• 2012

1. Objectives : The aim of the present study was to describe the Korea Constitutional Multicenter Bank (KCMB), which was various clinical data bank for scientific advancement of constitutional diagnosis and treatment. 2. Methods and Results : The KCMB is based on the 28 multi-institute cooperative clinical research networks including domestic and international institute. Since the KCMB was founded in 2006, data have been accumulated from 10,412 subjects. The KCMB consists of three parts: The clinical constitutional data, the measurement data, and the biological data. The method of data entry is via web based electronic Case Report From (eCRF). The eCRF has been developed and programed to ensure the efficient entry of data. We also developed coding manual, ongoing quality control assessment to obtain high-quality data. 3. Conclusions : The KCMB with various data contribute to providing the scientification of Sasang Constitutional Medicine.

• 한국비블리아학회지
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• 제24권1호
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• pp.149-169
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• 2013

본 연구는 이용자의 요구에 필요한 자원을 확보하기 위해 지역사회 내의 작은도서관들이 연계 및 협력하는 네트워크의 특성을 탐색적으로 분석하였다. 이를 위해 부천지역 내의 60개의 작은도서관을 대상으로 협력네트워크에 관한 관계데이터를 수집하였다. 네트워크의 구조적인 특성을 분석하기 위해 사회연결망분석법을 사용하였다. 분석 결과 공립작은도서관 간에는 연계가 긴밀하게 이루어지고 있었다. 중심성에서도 공립작은도서관이 상위그룹을 형성하였고 지방자치단체 등 외부 행위자를 포함한 네트워크에서도 공공도서관과 공립작은도서관이 중심적인 역할을 수행하고 있는 것으로 나타났다. 반면에 사립작은도서관은 대부분 고립되어 있어 연계가 미약한 것으로 분석되었다.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제9권9호
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• pp.3432-3448
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• 2015

Interference can cause serious problems in our daily life. Traditional ways in localizing a target can't work well when it comes to the source of interference for it may take an uncooperative or even resistant attitude towards localization. To tackle this issue, we take the BPSN (Binary Proximity Sensor Networks) and consider a passive way in this paper. No cooperation is needed and it is based on simple sensor node suitable for large-scale deployment. By dividing the sensing field into different patches, when enough patches are formed, good localization accuracy can be achieved with high resolution. Then we analyze the relationship between sensing radius and localization error, we find that in a finite region where edge effect can't be ignored, the trend between sensing radius and localization error is not always consistent. Through theoretical analysis and simulation, we explore to determine the best sensing radius to achieve high localization accuracy.

• 한국군사과학기술학회지
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• 제14권3호
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• pp.501-508
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• 2011

In this paper, we propose a channel allocation algorithm of MSAP(Mobile Subscriber Access Point) and data delivery scheme exploiting the symbol level network coding. The network is comprised of TS(Tactical Switch) as a backbone node, MSAPs, and TMFTs(Tactical Multi-Function Terminal). The TS performs the channel allocation considering the communication range overlapping between the neighboring MSAPs and applies the symbol level network coding, if necessary, depending on the position of the TMFTs. Assuming the number of available antennas of TMFT and MSAP will be extended to two from one, we propose two schemes: single mode and dual mode. Through the simulation, we show that the proposed delivery scheme provides higher delivery ratio and lower delivery delay compared with the legacy store-and-forward scheme.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.591-593
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• 2016

Device-to-device (D2D) communications underlaid cellular infrastructure is an competitive local area services technology to promote spectrum usage for next generation cellular networks. These potential can only be tap through efficient interference coordination. Previous works only concentrated on interference from D2D pairs whiles interference from CUs to D2D pairs were neglected. This work focus on solving uplink interference problem emanating from multiple CUs sharing its resource with multiple D2D pairs. The base station (BS) acting as a supervisor selfishly institute a pricing scheme to manage the interference it experience from D2D pairs based on its Quality of service (QoS) requirement. D2D pairs following the supervisor make power allocation decisions considering the price from the BS in a non-cooperative game fashion. In order for the D2D pairs to also meet their QoS requirement, they suggest a price to the BS called discount price which reflects the interference they receive from the CUs. Finally, we analyze the proposed approach.

• Journal of Communications and Networks
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• 제18권2호
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• pp.261-269
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• 2016

In this paper, the impact of energy constraints on a two-hop network with a source, a relay and a destination under random medium access is studied. A collision channel with erasures is considered, and the source and the relay nodes have energy harvesting capabilities and an unlimited battery to store the harvested energy. Additionally, the source and the relay node have external traffic arrivals and the relay forwards a fraction of the source node's traffic to the destination; the cooperation is performed at the network level. An inner and an outer bound of the stability region for a given transmission probability vector are obtained. Then, the closure of the inner and the outer bound is obtained separately and they turn out to be identical. This work is not only a step in connecting information theory and networking, by studying the maximum stable throughput region metric but also it taps the relatively unexplored and important domain of energy harvesting and assesses the effect of that on this important measure.

• Journal of Communications and Networks
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• 제15권2호
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• pp.173-178
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• 2013

It is a concern that eco-driving vehicles, because their driving behavior differs from other vehicles due to e.g. e-start, may inhibit smooth traffic flow. Therefore, it is necessary to study the cooperative eco-driving done by a vehicle group, putting "vehicle-to-vehicle communication" and "road-to-vehicle communication" into perspective. Based on these factors, this study aimed to: 1) Analyze fuel consumption rates and driving behaviors of more than one vehicle following an Eco-Driving vehicle. 2) Examine the effect of information on the fuel consumption rate of the preceding vehicles on the following vehicles. As a result, the following findings were obtained: 1) By providing information to multiple following vehicles, the fuel consumption rate of the second vehicle was not lowered, while that of the third one was. 2) It is possible that, when information on fuel consumption of a preceding vehicle is provided to the following one, an inter-vehicular distance is shortened during deceleration to contribute to smooth traffic flow. From the above results, it is suggested that, when targeting a vehicle group, sharing the information on preceding vehicles is effective.

• 기술혁신학회지
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• 제9권4호
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• pp.776-795
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• 2006

본 연구는 기술추격론 및 산업혁신체제론에 의거해서 국내 IT SoC산업의 기술추격을 검토했다. 국내 IT SoC산업은 많은 중소벤처 팹리스업체들의 출현에 의한 다양성 창조 및 일부 팹리스업체의 급성장에 따른 선택의 과정을 거쳐 급속한 기술추격 과정을 밟아왔다. 이 과정에서 국내 팹리스업체들은 틈새시장을 중심으로 한 경로개척형 기술추격을 수행해 왔다. 현재 국내 IT SoC산업은 많은 문제점을 가지고 있지만, 산업혁신체제의 공진화를 달성하려면 무엇보다도 기업간 협력네트워크 구축이 선결과제이다 기업간 협력네트워크는 시장의 힘에 의해 자동적으로 해결되기 어려운 시스템실패의 한 형태이기 때문에 이를 해결하기 위한 정부정책이 요망된다.

• 한국정보통신학회논문지
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• 제12권2호
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• pp.336-342
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• 2008

Amplify and forward(AF)와 decode and forward(DF)의 두 가지 모드에 대하여 네트워크의 네트워크 수명을 극대화할 수 있는 단순한 구조의 전력할당 방식을 제안한다. 네트워크 수명을 극대화하기 위해서는 전송전력을 최소화하는 것뿐만 아니라 전력을 네트워크의 모든 노드에게 균등하게 할당하는 것이 중요하다. 제안된 전력할당기법에서 송신전력은 노드의 잔여전력에 비례하고 목적지 노드에서 요구되는 수신 SNR을 만족하도록 할당된다. 본 논문에서는 AF와 DF의 두 가지 모드에 대하여 할당전력을 계산하였고 시뮬레이션을 통하여 그 성능을 분석하였다. 시뮬레이션 결과 제안된 전력할당 방식은 균등할당방식에 비하여 네트워크 수명을 크게 증가시킬 수 있었다.