• 전기학회논문지
• /
• 제59권11호
• /
• pp.1964-1970
• /
• 2010

A new intelligent power network (Smart Grid) that grafts some new technologies, such as the extension of the new and reproducible energy, electric motors, and electric storages, onto the regulation of green house gases according to the recent convention on climate changes has been actively promoted. As establishing such an intelligent power network, it is possible to implement a real-time rate system according to the change from the conventional single directional information transmission to the bidirectional information transmission. Such a real-time rate system can provide power during the chip rate hour by avoiding the high rate hour although customers use the same level of power through providing such real-time rate information including power generation costs. In this study, the establishment of an operating system that makes an effective use of the real-time rate system and its operation method are to be proposed.

• 한국멀티미디어학회논문지
• /
• 제25권8호
• /
• pp.1075-1084
• /
• 2022

Internet of Things(IoT) has become a key available technology for efficiently implementing device to device(D2D) services in various domains such as smart home, healthcare, smart city, agriculture, energy, logistics, and transportation. A lightweight publish/subscribe(Pub/Sub) messaging protocol not only establishes data dissemination pattern but also supports connectivity between IoT devices and their applications. Also, a Pub/Sub broker is deployed to facilitate data exchange among IoT devices. A scalable edge-based publish/subscribe (Pub/Sub) broker overlay networks support latency-sensitive IoT applications. In this paper, we design a hypercube grid quorum(HGQ) for distributed Pub/Sub systems based IoT applications. In designing HGQ, the network of hypercube structures suitable for the publish/subscribe model is built in the edge layer, and the proposed HGQ is designed by embedding a mesh overlay network in the hypercube. As their applications, we propose an HGQ-based mechansim for dissemination of the data of sensors or the message/event of IoT devices in IoT environments. The performance of HGQ is evaluated by analytical models. As the results, the latency and load balancing of applications based on the distributed Pub/Sub system using HGQ are improved.

• 한국위성정보통신학회논문지
• /
• 제11권2호
• /
• pp.42-47
• /
• 2016

최근 태양광, 에너지 저장 시스템 등의 발전으로 인해 가정에서 에너지 관리 시스템을 구축하고 에너지 생산을 스스로 하고자 하는 에너지 자립형 스마트 홈 시스템에 대한 연구가 활발해 지고 있다. 특히, 일본의 경우 후쿠시마 원전 사태 이후 전력망의 불안정성으로 인해 태양광을 통해 발전하고 이를 전력 에너지 저장 시스템에 저장하고 사용하는 가정용 시스템이 상용화되었다. 북미나 유럽에서도 태양광과 에너지 저장 시스템을 결합하여 신재생에너지 보급사업을 통해 보조금을 지급하면서 설치 가정을 확대하고 있다. 본 논문에서는 댁내 홈 네트워크를 통해 태양광과 에너지 저장 시스템을 연결하고 실시간 요금제에 기반을 둔 에너지 자립형 스마트 홈 시스템 개발에 대해 기술한다. 사용자의 개입을 최소화하면서 자동화된 운전으로 전력망으로부터의 에너지 사용을 최적화하여 에너지 자립형 홈을 구현하였다.

• 한국콘텐츠학회논문지
• /
• 제12권11호
• /
• pp.511-518
• /
• 2012

본 연구는 녹색기술 분야의 지식지도를 구축하고 국내외 녹색기술 정보를 시계열로 비교 분석하여 녹색기술에 대한 연구동향을 파악하고 향후 녹색기술 분야에서 활발하게 연구될 영역을 확인하고자 하였다. 이를 위해 한국과학기술정보연구원에서 운영 중인 녹색기술정보포털 (www.gtnet.go.kr)에서 제공하고 있는 녹색기술 정보의 키워드를 대상으로 네트워크 분석을 수행하였다. 네트워크 분석은 키워드를 이용하여 수행하였으며, 이를 시기별로 나누어 연구주제의 변화를 확인하였다. 그 결과 전체 영문 키워드 중 상위 100대 키워드에 대한 네트워크 분석 결과 주로 태양광 에너지, 바이오매스 등 재생에너지 관련 분야의 중심성이 높은 것으로 나타났다. 또한 년도별 주요 키워드에 대한 추세를 살펴보았을 때, Solar Cell, Nanotechnology, Smart Grid, Fuel Cell 등의 중심성이 증가하고 있는 것으로 나타나, 재생 에너지의 생성 및 활용 분야에 대한 연구개발이 활발히 이루어지고 있는 것으로 나타났다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제16권12호
• /
• pp.3889-3903
• /
• 2022

To address the problem of low detection accuracy due to training noise caused by mislabeling when Tri-training for network intrusion detection (NID), we propose a Tri-training algorithm based on cross entropy and K-nearest neighbors (TCK) for network intrusion detection. The proposed algorithm uses cross-entropy to replace the classification error rate to better identify the difference between the practical and predicted distributions of the model and reduce the prediction bias of mislabeled data to unlabeled data; K-nearest neighbors are used to remove the mislabeled data and reduce the number of mislabeled data. In order to verify the effectiveness of the algorithm proposed in this paper, experiments were conducted on 12 UCI datasets and NSL-KDD network intrusion datasets, and four indexes including accuracy, recall, F-measure and precision were used for comparison. The experimental results revealed that the TCK has superior performance than the conventional Tri-training algorithms and the Tri-training algorithms using only cross-entropy or K-nearest neighbor strategy.

• IEIE Transactions on Smart Processing and Computing
• /
• 제5권1호
• /
• pp.35-42
• /
• 2016

Developments in power electronics have enabled the widespread application of Pulse Width Modulation (PWM) inverters, notably for connecting renewable systems to the grid. This study demonstrates that a high-quality power can be achieved using a stand-alone inverter, whereby the comparison between the power quality of the stand-alone inverter with battery storage (off-grid) and the power quality of the utility network is presented. Multi-loop control techniques for a single phase stand-alone inverter are used. A capacitor current control is used to give active damping and enhance the transient and steady state inverter performance. A capacitor current control is cheaper than the inductor current control, where a small current sensing resistor is used. The output voltage control is used to improve the system performance and also control the output voltage. The inner control loop uses a proportional gain current controller and the outer loop is implemented using internal model control proportional-integral-derivative to ensure stability. The optimal controls are achieved by using the Sisotool tool in MATLAB/Simulink. The outcome of the control scheme of the numerical model of the stand-alone inverter has a smooth and good dynamic performance, but also a strong robustness to load variations. The numerical model of the stand-alone inverter and its power quality are presented, and the power quality is shown to meet the IEEE 519-2014. Furthermore, the power quality of the off-grid system is measured experimentally and compared with the grid power, showing power quality of off-grid system to be better than that of the utility network.

• 디지털융복합연구
• /
• 제14권5호
• /
• pp.333-339
• /
• 2016

인터넷 기반 전력 수요 관리 망에서 소비자와 공급자간 전기에너지 공급과 사용을 최적화, 효율화하기 위한 기술은 스마트 그리드 망에서 핵심 요소 기술로 대두되고 있다. 현재 전력 수요 관리 망에서 수요 반응 신호를 전기에너지 공급자와 시스템 제공자 및 사용자까지 전달하는 개방형 자동수요반응 표준 프로토콜은 openADR 2.0b가 사용되고 있다. 본 논문은 가장 신뢰성 있고 전 세계적으로 확산되어 있는 EPRI 오픈 소스를 사용하여 개발한 VEN, VTN 시스템의 다양한 공격 취약성에 대한 분석을 목적으로 하고 있다. 공격용 시뮬레이터를 이용하여 EPRI 오픈 소스로 구현한 VEN, VTN 시스템을 다양한 방법으로 공격하여 분석을 수행하였고 분석 결과 VEN, VTN 시스템이 파라미터 변조 공격, 서비스 플로우 변조 공격에 대한 보안 취약성이 존재한다는 결과를 얻을 수 있었다. 개방형, 양방향 통신 환경의 스마트 그리드 망에서 openADR 2.0b 프로토콜을 구현할 때는 다양한 보안 취약성을 고려한 프로토콜에 특화된 보안 기술이 반드시 모색되어야 한다는 결론을 얻을 수 있었다.

• ETRI Journal
• /
• 제38권1호
• /
• pp.41-51
• /
• 2016

Smart metering systems have become widespread around the world. RF mesh communication systems have contributed to the creation of smarter and more reliable power systems. This paper presents an algorithm for positioning GPRS concentrators to attain delay constraints for a ZigBee-based mesh network. The proposed algorithm determines the number and placement of concentrators using integer linear programming and a queueing model for the given mesh network. The solutions given by the proposed algorithm are validated by verifying the communication network performance through simulations.

• 한국멀티미디어학회논문지
• /
• 제22권8호
• /
• pp.913-922
• /
• 2019

The Internet of Things (IoT) envisions smart objects collecting and sharing data at a massive scale via the Internet. One challenging issue is how to disseminate data to relevant data consuming objects efficiently. In such a massive IoT network, Mission critical data dissemination imposes constraints on the message transfer delay between objects. Due to the low power and communication range of IoT objects, data is relayed over multi-hops before arriving at the destination. In this paper, we propose a quorum-based adaptive dissemination algorithm (QADA) for the critical data in the monitoring-based applications of massive IoTs. To design QADA, we first design a new stepped-triangular grid structures (sT-grid) that support data dissemination, then construct a triangular grid overlay in the fog layer on the lower IoT layer and propose the data dissemination algorithm of the publish/subscribe model that adaptively uses triangle grid (T-grid) and sT-grid quorums depending on the mission critical in the overlay constructed to disseminate the critical data, and evaluate its performance as an analytical model.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2015년도 제46회 하계학술대회
• /
• pp.55-56
• /
• 2015

A smart meter is a kind of electronic meters that measures and records consumption of electric energy in intervals of an hour or less and transmits that information to the remote places. AMI provides two-way communication path between utilities and consumers and should be able to support smart grid's new functionalities such as demand-response actions and real time pricing. The main objective of this paper is to provide a new diagnosis method and system for testing of smart meters in AMI neighborhood area network.