• 한국전자통신학회논문지
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• 제5권2호
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• pp.193-204
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• 2010

무선 멀티미디어 센서 네트워크(Wireless Multimedia Sensor Network : WMSN)는 기존 스칼라 데이터 뿐만 아니라 음성, 이미지, 동영상 등 다양한 멀티미디어 정보를 전달해야 하므로 다양한 특성을 가진 트래픽을 효율적으로 처리하기 위한 서비스 품질(Quality of Service : QoS)를 지원할 수 있는 메커니즘이 필요하다. 본 논문은 WMSN 에서의 트래픽 유형을 주기적 모니터링 트래픽, 이벤트 트래픽, 멀티미디어 트래픽, 쿼리 기반 트래픽으로 분류하고, 각 트래픽 유형에 따라 지연, 에너지 효율성 및 신뢰성에 대해 차별화된 QoS를 제공할 수 있는 마킹 알고리즘과 큐 관리 메커니즘을 제안한고, 시뮬레이션을 통해 성능을 분석한다.

• Journal of Communications and Networks
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• 제13권5호
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• pp.494-498
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• 2011

Satellite digital multimedia broadcasting (S-DMB) systems use gap fillers (GFs) to provide wireless multimedia services to non-line-of-sight locations. GFs act as repeaters, and S-DMB systems require GF networks in order to guarantee mobile reception. Each GF covers a cell or sector. In order to provide contiguous coverage of an area comprising two or more cells or sectors, multiple GFs are needed. However, when multiple GFs are situated close to each other, interference is likely to occur. As a result, in this study, we have investigated system-level environments for planning the design of interference-free GF networks in S-DMB systems. Our investigations revealed that S-DMB services are unavailable because of quality deterioration caused by interference when the delay attributable to a GF and the satellite signals exceeds ${\pm}$256 chips and the distance between the GF and its reception terminal is greater than 4.6 km. On the basis of this analysis, we conducted a field test that confirmed that the above-mentioned time delay can be controlled in such a way as to ensure high quality S-DMB services.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제10권12호
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• pp.5286-5306
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• 2016

Emerging applications in automation, medical imaging, traffic monitoring and surveillance need real-time data transmission over Wireless Sensor Networks (WSNs). Guaranteeing Quality of Service (QoS) for real-time traffic over WSNs creates new challenges. Rapid penetration of smart devices, standardization of Machine Type Communications (MTC) in next generation 5G wireless networks have added new dimensions in these challenges. In order to satisfy such precise QoS constraints, in this paper, we propose a new cross-layer QoS-provisioning strategy in Wireless Multimedia Sensor Networks (WMSNs). The network layer performs statistical estimation of sensory QoS parameters. Identifying QoS-routing problem with multiple objectives as NP-complete, it discovers near-optimal QoS-routes by using evolutionary genetic algorithms. Subsequently, the Medium Access Control (MAC) layer classifies the packets, automatically adapts the contention window, based on QoS requirements and transmits the data by using routing information obtained by the network layer. Performance analysis is carried out to get an estimate of the overall system. Through the simulation results, it is manifested that the proposed strategy is able to achieve better throughput and significant lower delay, at the expense of negligible energy consumption, in comparison to existing WMSN QoS protocols.

• 한국통신학회논문지
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• 제39C권3호
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• pp.247-254
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• 2014

무선 멀티미디어 센서 네트워크는 이미지 센서나 마이크 센서에 의해 주기적으로 생성된 멀티미디어 데이터를 효율적으로 전송하기 위해서 가장 적합한 채널을 선택하는 것이 중요하다. 대부분의 기존 연구에서는 무선 센서 네트워크가 사용할 채널을 미리 고정하는 경우가 많았지만, 주파수 부족 문제가 심각한 현실에서는 특정 채널을 고정적으로 사용한다는 것이 다양한 환경을 지원하는데 큰 제약이 될 수 있다. 본 논문에서는 이를 개선하기 위해서 기존 무선 인지 라디오 네트워크(Cognitive radio network)에서 사용하는 공통 제어 채널 없이 두 노드가 서로 사용 가능한 채널을 찾기 위한 방식을 도입하였다. 또한 기존 방식의 문제점으로 사용하는 채널수가 늘어날수록 성능이 크게 저하됨을 보이고, 이를 개선하기 위해 새로운 방식을 제안하였다. 따라서 제안 방식은 네트워크의 노드 밀도가 증가할수록 다른 방식에 비해 30% 이상 빠르게 링크를 설정할 수 있다.

• 통합자연과학논문집
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• 제5권3호
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• pp.182-185
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• 2012

In this paper, For 4th generation wireless communication systems, we propose a method to predict FH patterns in FH-OFDMA systems. OFDM is recognized as a promising modulation technique. Multi-user allocation in OFDM system can use FH that provides the spectrum-spread techniques. If one can generate more predictable FH sequences, then performance of the system can be easily improved. Current random FH and simple adaptive FH methods, however, are not considering predicting FH sequences. In this paper we show that the sampling of the wireless faded signal is not realized as a certain probability nature. With this regard, the proposed predictive FH allocation method is designed to embed the unknown probability models. Simulation study shows that the predictive FH method is more accurately predict FH sequences than the random or simple adaptive FH methods. We will further improve this proposed method to apply QoS control and MAC function development in OFDMA based wireless physical structures, especially maritime wireless data communications.

• 한국경영과학회지
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• 제34권1호
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• pp.39-59
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• 2009

Game theory is adapted to a variety of domains such as economics, biology, engineering, political science, computer science, and philosophy in order to analyze economic behaviors. This research is an application of game theory to wireless communication. In particular, in terms of bargaining game we dealt with a multimedia resource allocation problem in wireless communication, which is rapidly spreading such as Wibro, WCDML, IPTV, etc. The algorithm is assumed to allocate multimedia resources to users who can choose and access differentiated media services. For this purpose, 3 utility function of users is devised to reflect quality of service (QoS) and price. We illustrated experimental results with synthesis data which were made to mimic real multimedia data, and analyzed differentiated service providing and the effect of the utility function.

• 한국경영과학회:학술대회논문집
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• 한국경영과학회 2008년도 추계학술대회 및 정기총회
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• pp.164-178
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• 2008

Game theory is adapted to a variety of domains such as economics, biology, engineering, political science, computer science, and philosophy in order to analyze economic behaviors. This research is an application of game theory to wireless communication. In particular, in terms of bargaining game we dealt with a multimedia resource allocation algorithm in wireless communication, which is rapidly spreading such as Wibro, WCDML, IPTV, etc. The algorithm is assumed to allocate multimedia resources to users who can choose and access differentiated media services. For this purpose, a utility function of users is devised to reflect quality of service (QoS) and price. We illustrated experimental results with synthesis data which were made to mimic real multimedia data, and analyzed differentiated service providing and the effect of the utility function.

• 한국콘텐츠학회:학술대회논문집
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• 한국콘텐츠학회 2005년도 추계 종합학술대회 논문집
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• pp.340-344
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• 2005

차세대 무선 망 시스템에서는 멀티미디어 서비스가 당연히 요구되며 그리고 경제적인 패킷 데이터 전송은 필수적이다. 이러한 점에서, OFDMA (WiBro) 시스템에서는 다양한 트래픽 클라스를 최적하게 제어할 수 있는 적응적 자원관리 방법이 요구된다. 본 논문은 과거의 서브 채널 상태정보를 기반으로 최근 서브 채널 상태를 예측하는 알고리즘을 개발하였고 이 방법을 이용하여 또한 다운링크의 멀티미디어 트래픽을 효과적으로 제어하는 스케줄링 알고리즘을 개발하였다.

• 한국멀티미디어학회논문지
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• 제18권8호
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• pp.909-914
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• 2015

In wireless sensor networks, sensor nodes have a short transmission range and data is transferred from source to destination node using the multi-hop transmission. Sensor nodes are powered by battery and the link qualities are different, and the routing protocol in the wireless sensor network is one of the important technical issues. Multipath routing was proposed to reduce the data congestion and increase data throughput. In the multipath routing, however, each path can be interfered by the other path, and it can aggravate network performance. In this paper, we propose the multipath routing scheme for multi-rate wireless sensor networks. The multipath routing selects transmission paths to minimize transmission delay and path interference.

• 한국멀티미디어학회논문지
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• 제17권6호
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• pp.687-696
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• 2014

An integrated ship area network has functionality of remote control and autonomous management of various sensors and instruments embedded or boarded in a ship. For such environment, an wireless bridge is essential to transmit control and/or managing information to sensors or instruments from a central integrated ship area network station. In this paper, one of reliable schemes of WiMedia based wireless bridge using relay cooperative transmission using WiMedia distributed MAC protocol is proposed to increase a communication reliability between cluster headers, irrespective of channel variation. Simulation results show that the proposed wireless bridge using relay cooperative transmission scheme increases communication reliability.