• Progress in Superconductivity and Cryogenics
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• v.12 no.3
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• pp.34-38
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• 2010

Until now some countries including South Korea have made big progress and many efforts in the development of high temperature superconductor (HTS) power equipments. Especially, HTS Cable and superconducting fault current limiter (SFCL) are the strongest candidates among them from the viewpoint of applying to real grid. In South Korea, HTS cable and SFCL have been installed in test fields and tested successfully at Gochang PT Center of KEPCO. In order to meet practical requirements and be feasible in real grid, a demonstration project for HTS cable and SFCL systems, called GENI(green superconducting electric power network at Icheon substation) project, has been initiated to install 23kV HTS cable and SFCL systems in a utility network in South Korea since 2008. Namely, it says the first demonstration project for the application HTS system to real smart grid in South Korea. This paper presents the design and the application plan of the 22.9kV HTS cable and SFCL in 154kV Icheon substation in South Korea with the viewpoint of applying in Smat Grid.

• Journal of Korea Society of Digital Industry and Information Management
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• v.10 no.3
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• pp.207-221
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• 2014

Education environment of modern society is rapidly changing along the usage of various device and development of contents. Learners of diverse age groups and genders are exposed in smart education environment. Thus in order to investigate effective smart education contents production, this study classified interactive types that affect learning satisfaction into CAI (Computer Assisted Instruction) based , NCS (Network Communication System) based , and NTS (New Technology System) based . Then we investigated how each interactive types affect immersion, utility, self-efficacy, practicality, and stimulation. The effects were measured according to the learner's gender and age. As the result, interactive types do affect smart education, where male had higher learning satisfaction for CAI based, game type, and wiki type while female had higher satisfaction for relationship establishment type and experience type. Also, for age group, the 10s preferred NTS based, 20~30s NCS based, and 40s and over CAI based interactive type. Thus, if satisfaction levels according to gender and age are considered when producing smart education contents, it may be possible to create educative contents that meet the dispositions of the learners.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.9
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• pp.3151-3168
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• 2021

Internet of Things (IoT) connects several objects with embedded sensors and they are capable of exchanging information between devices to create a smart environment. IoT smart devices have limited resources, such as batteries, computing power, and bandwidth, but comprehensive sensing causes severe energy restrictions, lowering data quality. The main objective of the proposal is to build a hybrid protocol which provides high data quality and reduced energy consumption in IoT sensor network. The hybrid protocol gives a flexible and complete solution for sensor selection problem. It selects a subset of active sensor nodes in the network which will increase the data quality and optimize the energy consumption. Since the unused sensor nodes switch off during the sensing phase, the energy consumption is greatly reduced. The hybrid protocol uses Dijkstra's algorithm for determining the shortest path for sensing data and Ant colony inspired variable path selection algorithm for selecting active nodes in the network. The missing data due to inactive sensor nodes is reconstructed using enhanced belief propagation algorithm. The proposed hybrid method is evaluated using real sensor data and the demonstrated results show significant improvement in energy consumption, data utility and data reconstruction rate compared to other existing methods.

• KEPCO Journal on Electric Power and Energy
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• v.3 no.2
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• pp.73-78
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• 2017

Recently, a number of foreign electric power companies including domestic Korea Electric Power Corporation (KEPCO) have actively engaged in the construction of a power grid with the concept of a smart grid. The Smart grid is a technology that increases the efficiency of the power by converging the information network with the power grid. It can maximize the energy efficiency through the two-way communication between the utility and the consumer. However, as the power grid converges with the information and communication network, security threats are increasing more than existing power grids. Due to the nature of the power grid, the damage caused by security threats is not only personal privacy but also economic loss of society. So smart grid becomes the target of hackers. In this paper, we discuss security vulnerabilities of Advanced Metering Infrastructure (AMI), which is a core technology of smart grid construction, and the corresponding security technologies to prevent security damage of smart grid.

• Journal of Advanced Navigation Technology
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• v.15 no.4
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• pp.585-590
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• 2011

In the past few years, M2M (Machine-to-Machine) applications have become a hot topic in the wireless industry. While M2M applications can be used for many purposes (smart homes, smart metering/electricity meter reading, fleet management, mobile workforce, automobile insurance, vending machines, etc), and in many sectors (healthcare, agriculture, commercial, industrial, retail, utility, etc.), smart metering applications or smart grids present the biggest growth potential in the M2M market today. M2M platform is the future ubiquitous network technologies which provide the integrated service with the networks and devices. The promising technologies to tackle these problems are the Semantic technologies, for interoperability, and the Agent technologies for management of complex systems. In this paper the information communication technique based on the disaster prevention system's for the M2M, concepts and its requirement technology and application are studied.

• JSTS:Journal of Semiconductor Technology and Science
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• v.13 no.4
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• pp.272-281
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• 2013

This paper presents low power frequency shift keying (FSK) transmitter using all digital PLL (ADPLL) for smart utility network (SUN). In order to operate at low-power and to integrate a small die area, the ADPLL is adopted in transmitter. The phase noise of the ADPLL is improved by using a fine resolution time to digital converter (TDC) and digitally controlled oscillator (DCO). The FSK transmitter is implemented in $0.18{\mu}m$ 1-poly 6-metal CMOS technology. The die area of the transmitter including ADPLL is $3.5mm^2$. The power consumption of the ADPLL is 12.43 mW. And, the power consumptions of the transmitter are 35.36 mW and 65.57 mW when the output power levels are -1.6 dBm and +12 dBm, respectively. Both of them are supplied by 1.8 V voltage source. The frequency resolution of the TDC is 2.7 ps. The effective DCO frequency resolution with the differential MOS varactor and sigma-delta modulator is 2.5 Hz. The phase noise of the ADPLL output at 1.8 GHz is -121.17 dBc/Hz with a 1 MHz offset.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.1
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• pp.11-23
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• 2014

Wireless Mesh Network(WMN) has drawn much attention due to easy deployment and good scalability. Recently, major power utilities have been focusing on R&D to apply WMN technology in Smart Grid Network. Smart Grid is an intelligent electrical power network that can maximize energy efficiency through bidirectional communication between utility providers and customers with ICT(Information Communication Technology). It is necessary to guarantee QoS of some important data in Smart Grid system such as real-time data delivery. In this paper, we suggest QoS enhancement method for WMN based Smart Grid system using IEEE 802.11s. We analyze Smart Grid Application characteristics and apply IEEE 802.11s WMN scheme for Smart Grid in domestic power communication system. Performance evaluation is progressed using NS-2 simulator implementing IEEE 802.11s. The simulation results show that the QoS enhancement scheme can guarantee stable bandwidth irrespective of traffic condition due to IEEE 802.11s reservation mechanism.

• Journal of Information Technology Services
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• v.11 no.3
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• pp.17-38
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• 2012

Social network service(SNS), provided by social network sites such as Facebook, Twitter and Cyworld is rapidly growing in online business. Furthermore, many companies have growing interests in finding effective ways to use SNSs for their innovations, marketing and advertisement. In fact, firms have recognized the utility value of the SNS for their business. In this aspect, this study attempts to identify key factors influencing the intention to continuous use of SNSs. Based on the UTAUT(the Unified Theory of Acceptance and Usage of Technology)model, this study proposes the research model, including the effects of social network service characteristics(social relationship support, information sharing, image expression) and individual characteristics(self-disclosure, extroversion, familiarity) on performance expectancy as well as the moderating effect of perceived information security among UTAUT variables. The 412T sets of data collected in a survey were tested against the modeling using SEM using SmartPLS. Results indicated that social network service and individual characteristics had significant effect on performance expectancy with exception of self-disclosure. In addition, the moderating effect of perceived information security had significant effect. The results had important implications for firms providing SNSs hoping to develop a successful business model.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.1
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• pp.11-27
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• 2017

The road network system of major domestic urban areas such as city of Seoul was rapidly developed and regionally expanded. In addition, many kinds of life-lines such as electrical cables, telephone cables, water&sewerage lines, heat&cold conduits and gas lines were needed in order for urban residents to live comfortably. Therefore, most of the life-lines were individually buried in underground and individually managed. The utility tunnel is defined as the urban planning facilities for commonly installing life-lines in the National Land Planning Act. Expectation effectiveness of urban utility tunnels is reducing repeated excavation of roads, improvement of urban landscape; road pavement durability; driving performance and traffic flow. It can also be expected that ensuring disaster safety for earthquakes and sinkholes, smart-grind and electric vehicle supply, rapid response to changes in future living environment and etc. Therefore, necessity of urban utility tunnels has recently increased. However, all of the constructed utility tunnels are cut-and-cover tunnels domestically, which is included in development of new-town areas. Since urban areas can not accommodate all buried life-lines, it is necessary to study the feasibility assessment system for utility tunnel by urban patterns and capacity optimization for urban utility tunnels. In this study, we break away from the new-town utility tunnels and suggest a quantitative assessment model based on the evaluation index for urban areas. In addition, we also develop a program that can implement a quantitative evaluation system by subdividing the feasibility assessment system of urban patterns. Ultimately, this study can contribute to be activated the urban utility tunnel.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.566-571
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• 2011

As Plug-in Hybrid Vehicle and Electric Vehicle (PHEV/EV) take a greater share in the personal automobile market, their high penetration levels may bring potential challenges to electric utility especially at the distribution level. Thus, there is a need for the flexible charging management strategy to compromise the benefits of both PHEV/EV owners and power grid side. There are many different management methods that depend on the objective function and the constraints caused by the system. In this paper, the schema and dispatching schedule of centralized PHEV/EV charging spot network are analyzed. Also, we proposed and compared three power allocation strategies for centralized charging spot. The first strategy aims to maximize state of vehicles at plug-out time, the rest methods are equalized allocation and prioritized allocation based on vehicles SoC. The simulation results show that each run of the optimized algorithms can produce the satisfactory solutions to response properly the requirement from PHEV/EV customers.