• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.3
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• pp.263-269
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• 2017

This paper proposes a novel circulating current control method for an MMC-HVDC system based on Vector PI control. The method can suppress second-order harmonics of the circulating currents under balanced and unbalanced grid conditions. The proposed method is robust to grid frequency variation. The effectiveness of the proposed method is verified through frequency response and time domain simulation.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.336-344
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• 2017

This paper presents the three-port DC-DC converter modeling and controller design procedure, which is part of the solid-state transformer (SST) to interface medium voltage AC grid to bipolar DC distribution network. Due to the high primary side DC link voltage, the proposed converter employs the three-level neutral point clamped (NPC) topology at the primary side and 2-two level half bridge circuits for each DC distribution network. For the proposed converter particular structure, this paper conducts modeling the three winding transformer and the power transfer between each port. A decoupling method is adopted to simplify the power transfer model. The voltage controller design procedure is presented. In addition, the output current sharing controller is employed for current balancing between the parallel-connected secondary output ports. The proposed circuit and controller performance are verified by experimental results using a 30 kW prototype SST system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.2
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• pp.540-546
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• 2014

Recently a new government has announced an action plan known as the government 3.0, which aims to provide customized services for individual people, generate more jobs and support creative economy. Leading on from previous similar initiatives, the new scheme seeks to focus on open, share, communicate, and collaborate. In promoting Government 3.0, the crucial factor might be how to align the core services and policies of Government 3.0 with correspoding technologies. The paper describes the concepts and features of Government 3.0, identifies emerging Internet-based technologies and services toward the initiative, and finally provides improvement plans for Government 3.0. As a result, 10 issues to be brought together include: Smart Phone Applications and Service, Mobile Internet Computing and Application, Wireless and Sensor Network, Security & Privacy in Internet, Energy-efficient Computing & Smart Grid, Multimedia & Image Processing, Data Mining and Big Data, Software Engineering, Internet Business related Policy, and Management of Internet Application.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.810-813
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• 2012

차세대 전력망인 스마트그리드의 구축에 필수적인 AMI는 소비자의 전력 사용 관리를 위해 양방향 통신이 가능한 스마트 기기로 구성된다. 스마트 기기 간의 송수신 되는 소비자의 전력 사용 정보 흐름의 안전성 확보를 위해 제안하는 상호 인증 방안은 MDMS를 통한 지역적 인증이 가능하고, ID를 기반으로 스마트 기기 간 상호 인증을 제공한다. 이에 따라 스마트 기기 간의 안전한 통신 환경을 제공한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.11a
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• pp.287-289
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• 2011

짧아지고 있는 업무시간과 더불어 주5일제의 등장으로 인해 가정에서의 활동시간이 늘어남에 따라 현대 사회에 가정 내의 생활은 상당한 부분을 차지하고 있다. 그로 인해 좀 더 편리하며 안락한 홈 생활은 누구나 원하며 그 중요성은 더 커질 것이라 예상된다. 그렇기 때문에 본 논문에서는 스마트한 홈 환경구축과 전 세계적으로 문제가 대두 되고 있는 과도한 에너지사용을 막기 위해 전력량절감에 초점을 두어 향후 에너지절감과 스마트한 홈 생활에 중점을 두었다.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1340-1347
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• 2017

Utilization of Electric Vehicles (EVs) have been growing popularity in recent years due to increment in fuel price and lack of natural resources. Random unexpected charging by home EV charger in distribution is predicted in the future. The power quality problems such as fluctuation of power factor in a residential distribution network was explored with random EV chargers. This paper proposes a high-performance nonlinear sliding mode controller (SMC) for an EV charging system to compensate voltage distortions and to enhance the power factor against the unbalanced EV chargers. For the verification of the proposed scheme, MATLAB-Simulink simulations are performed on 22.9-kV grid. The results show that the proposed scheme can improve the power factor of a smart grid due to the EV chargers on the grid.

• Journal of Satellite, Information and Communications
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• v.8 no.4
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• pp.95-99
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• 2013

GPS service is generally being used in the navigation application such as the car navigation and the smart phone. Recently, GPS service continues to increase in the timing application such as the mobile telecommunication network, the smart grid, and the financial network. As GPS signals are sensitive to GPS jamming, it should be monitored and protected. In oder to prevent and minimize the damage caused by GPS jamming, many countries are developing and operating GPS jamming monitoring system. This paper presents the implementation and the test results of the GPS jamming equipment which provides the detection, the direction finding and the location of GPS jamming.

• International Journal of Computer Science & Network Security
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• v.24 no.4
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• pp.87-106
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• 2024

Vehicle-to-Home (V2H) and Home Centralized Photovoltaic (HCPV) systems can address various energy storage issues and enhance demand response programs. Renewable energy, such as solar energy and wind turbines, address the energy gap. However, no energy management system is currently available to regulate the uncertainty of renewable energy sources, electric vehicles, and appliance consumption within a smart microgrid. Therefore, this study investigated the impact of solar photovoltaic (PV) panels, electric vehicles, and Micro-Grid (MG) storage on maximum solar radiation hours. Several Deep Learning (DL) algorithms were applied to account for the uncertainty. Moreover, a Reinforcement Learning HCPV (RL-HCPV) algorithm was created for efficient real-time energy scheduling decisions. The proposed algorithm managed the energy demand between PV solar energy generation and vehicle energy storage. RL-HCPV was modeled according to several constraints to meet household electricity demands in sunny and cloudy weather. Simulations demonstrated how the proposed RL-HCPV system could efficiently handle the demand response and how V2H can help to smooth the appliance load profile and reduce power consumption costs with sustainable power generation. The results demonstrated the advantages of utilizing RL and V2H as potential storage technology for smart buildings.

• Journal of Advanced Navigation Technology
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• v.26 no.3
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• pp.172-178
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• 2022

In this paper, water meter AMR(automatic meter reading), one of the core technologies of smart water grid, using LoRa IoT network is studied. The main content of the research is to develop the network system and show the test results that one PC server receives the readings of water meters from multiple households through LoRa communication and stores them in the database, and at the same time sends the data to the web server database through internet. The system also allows users to monitor the meter readings using their smartphones. The hardware and firmware of the main board of the digital water meter are developed. For a PC server program, MDMS(meter data management system) is developed using Visual C#. The app program running on the user's smartphone is also developed using Android Studio. By connecting each developed parts, the total network system is mounted on a flow test bench in the laboratory and tested. For the fields test, 5 places around the university are selected and the transmission distances are tested. The test result show that the developed system can be applied into the real field. The developed system can be expanded to various social safety nets such as monitoring the living alone or elderly with dementia.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.11
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• pp.2196-2204
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• 2015

Location-based density information of mobile node could be used well in various, new and expanding areas such as location-based services, internet of things, smart grid technologies, and intelligent building. In general, receiving mobile nodes of a wireless mobile node depend on the maximum communication range of transmitting mobile node. In this paper, efficient computing method for mobile node using Delaunay triangulation is proposed, which is irrespective of mobile node's maximum communication range and reflect relative location in a given situation. Proposed method may be good used to find out the density of network constructed by various max communication range devices as Internet of Things. This method suggested in this paper could work well for location-based services, internet of things, smart grid technologies, and intelligent building.