• 한국통신학회논문지
• /
• 제39A권10호
• /
• pp.622-624
• /
• 2014

본 논문은 OFDMA 셀룰러 네트워크 기반 최적 D2D 통신을 위한 모드 선택 및 자원할당 기법을 제안한다. 제안하는 기법은 단말의 채널 정보를 바탕으로 QoS를 만족하는 D2D-모드 가능 영역을 판별하고, Primal-Dual 알고리즘을 이용하여 최적의 해를 구한다. 시뮬레이션을 통해 제안하는 기법이 기존 기법대비 시스템 수율을 크게 개선함을 확인하였다.

• International Journal of Internet, Broadcasting and Communication
• /
• 제14권4호
• /
• pp.80-87
• /
• 2022

Lack of sufficient battery capacity is one of the most important challenges impeding the development of wireless sensor networks (WSNs). Recent innovations in the areas of wireless energy transfer and rechargeable batteries have made it possible to advance WSNs. Therefore, in this article, we propose an energy-efficient charging of sensors in a WSN scenario. First, we have formulated the problem as an integer linear programming (ILP) problem. Then a utility function-based greedy algorithm named UGreedy/UF1 is proposed for solving the problem. Finally, the performance of UGreedy/UF1 is analyzed along with other baseline algorithms: UGreedy/UF2, 2-opt TSP, and Greedy TSP. The simulation results show that UGreedy/UF1 performs better than others both in terms of the deadline missing ratio of sensors and the total energy consumption of UAVs.

• 한국통신학회:학술대회논문집
• /
• 한국통신학회 2006년도 하계종합학술발표회 논문 초록집
• /
• pp.530-530
• /
• 2006

• 한국전자통신학회논문지
• /
• 제9권1호
• /
• pp.131-136
• /
• 2014

본 논문에서는 패션 상품 수요 예측을 위하여 ARIMA 모형과 웨이블렛 신경회로망 모형을 결합한 상품 수요 예측 알고리즘을 개발하였다. 제시된 방법을 검증하기 위하여 2008년에서 2012년까지의 H사의 패션 상품 데이터를 바탕으로 다양한 알고리즘을 축하고 제안한 방법의 정확도를 분석하였다. 실험 결과 ARIMA 모형은 MAPE가 5.179%, 웨이블렛 신경회로망은 4.553%, 제안한 ARIMA + 웨이블렛 신경회로망 모형은 4.448%로 나타나 성능이 우수한 것으로 나타났다. 따라서 제안된 방법을 사용할 경우 패션 상품 수요 예측을 위해 유용하게 활용할 수 있음을 보였다.

• 한국전자통신학회논문지
• /
• 제6권1호
• /
• pp.1-6
• /
• 2011

본 연구는 재난안전 무선통신망 구축 활용을 위한 사업 중단으로 재난 관련 기관들의 무선통신망 미확보 및 장비노후화에 따라 인명 및 재산피해가 확산될 우려가 증대되고 있는 시점에서 연구 하에 예방책을 제시하고자 한다.

• 한국지능시스템학회논문지
• /
• 제14권5호
• /
• pp.660-665
• /
• 2004

In this study, a new architecture and comprehensive design methodology of genetically optimized Multi-layer Fuzzy Neural Networks (gMFNN) are introduced and a series of numeric experiments are carried out. The gMFNN architecture results from a synergistic usage of the hybrid system generated by combining Fuzzy Neural Networks (FNN) with Polynomial Neural Networks (PNN). FNN contributes to the formation of the premise part of the overall network structure of the gMFNN. The consequence part of the gMFNN is designed using PNN. The optimization of the FNN is realized with the aid of a standard back-propagation learning algorithm and genetic optimization. The development of the PNN dwells on the extended Group Method of Data Handling (GMDH) method and Genetic Algorithms (GAs). To evaluate the performance of the gMFNN, the models are experimented with the use of a numerical example.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2008년도 하계종합학술대회
• /
• pp.169-170
• /
• 2008

To achieve secure communication in current ZigBee networks, encrypted messages using security keys need to be shared among devices. A link key shared by two devices is used for unicast communications, where the master key is the starting point for establishing a link key. The ZigBee protocol has some limitations in end-to-end key establishment, which are discussed and an improved end-to-end key establishment scheme is presented.

• 한국정보전자통신기술학회논문지
• /
• 제9권5호
• /
• pp.445-450
• /
• 2016

In this paper we study the effect of chaos in nonuniform instability with optical fiber based IoT networks. The transient response of optically controlled fiber has also described. Nonlinear optical fiber effects especially fiber scattering in networks has emerged as the essential means active optical devices. The paradigm instability in fiber Internet serves as a test for fundamental study of chaos and its suppression and exploitation in practical application in optical communication. This paper attempts to present a survey and some of our research findings on the nature of chaotic effect on Internet based optical communication. The transient response in optical fiber has been evaluated theoretically by calculating the variation of the scattering function. The lines has used under open ended termination containing optically induced region. The scattered optical waves in a fiber used in optic communications are temporally unstable above certain threshold intensity.

• 한국정보전자통신기술학회논문지
• /
• 제8권5호
• /
• pp.405-411
• /
• 2015

본 논문에서 우리는 모바일 싱크노드를 가지는 모바일 센서 네트워크를 위한 경로배정 프로토콜을 제안합니다. 제안된 논문은 모바일 싱크를 도입하는 것에 의해 확장됩니다. 모바일 싱크는 그 주변의 클러스터 헤드로부터 센싱 데이터를 수집하는 가장 많은 멤버수를 가진 클러스터 헤드로 이동합니다. 이러한 이동은 싱크에 패킷을 보내는데 필요한 에너지소모를 감소시킵니다. 모의실험 결과는 제안된 프로토콜이 에너지 효율면에서 LEACH-ME를 능가하는 것을 보여줍니다.

• Journal of Communications and Networks
• /
• 제6권2호
• /
• pp.156-162
• /
• 2004

In recent years, mobile ad-hoc networks have received a great deal of attention in both academia and industry to provide anytime-anywhere networking services. As wireless networks are rapidly deployed, the security of wireless environment will be mandatory. In this paper, we describe a group key management architecture and key agreement protocols for secure communication in mobile ad-hoc wireless networks (MANETs) overseen by unmanned aerial vehicles (UAVs). We use implicitly certified public keys method, which alleviates the certificate overhead and improves computational efficiency. The architecture uses a two-layered key management approach where the group of nodes is divided into: 1) Cell groups consisting of ground nodes and 2) control groups consisting of cell group managers. The chief benefit of this approach is that the effects of a membership change are restricted to the single cell group.