• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.10a
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• pp.493-496
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• 2007

As the ubiquitous society period has set in recently, which resulted from both mass distribution of portable devices such as PDA, PMP, Smart Phones, the demand for more optional features of system and multimedia functions has been increasing. In compliance with thoses needs, the amount of information increased in a system and greater power capacities are needed more than ever. Therefore, in portable device which uses battery as a limited source of power, the power management has become a key factor in the system. This paper concentrates on the Power management solution for Smart device for the prevention of missing child. And ARM9 Core was used as CPU and Windows CE 5.0 was ported to the smart device.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.10
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• pp.1795-1803
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• 2011

Advanced Metering Infrastructure (AMI) is one of the important components to form a smart-gird, which is an advanced power system by combining the power system with the communication systems. This AMI makes it possible to exchange information between operators and consumers for the efficient and reliable operation of the power system through a smart meter or a In-Home Display. However, according to the increase of the demanded information such as the power quality, the accurate load-profile, and the billing data to help customers manage their power consumption, it is necessary to gather more accurate analytical data from each house appliances and transfer it to the smart meter for synthesizing the information and controlling each loads. In this paper, the development of the wireless data acquisition device for the individual load data metering, which is connected with the smart meter for advanced functions, is proposed. AVR, a kind of microcontroller, and Bluetooth are used and integrated into the proposed the wireless data acquisition device to transmit the detailed power data (voltage and current) to the smart meter. To verify the effectiveness of the proposed system, a hardware experiment is carried out including the confirmation of the possibility for providing the more various information by applying analysis algorithms to the obtained data. Also, the application structure of the wireless data acquisition device to gather the data from the various house appliances is presented.

• Journal of the Korea Society of Computer and Information
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• v.22 no.6
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• pp.123-129
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• 2017

In this paper, we proposed a smart multiple-tap system which a remote user with smartphone can control multiple-taps in order to reduce standby-power consumption more conveniently when plugged-in electric appliances are turned-off. Recently, several researches of smart multiple-tap using IoT technology has reported. However, in these researches, an additional device like as a server computer is necessary, or multiple-taps could be only remotely controlled by smartphone and not directly controlled by on/off switch. The proposed smart multiple-tap system does not need any additional device only if it has a WiFi router, and it can be used for user as well as remote control using smartphone application and physically direct control using contact switches like existing multiple-taps. Our approach is to develop a smart multiple-tap device capable of WiFi communication can each serve as a server or a client, and can be operated by the hybrid switch combining the on/off contact switch and the relay switch. We implemented the prototype of the proposed system composed of the smart multiple-tap device and the smartphone application, and the test of the prototype validates the proposed system.

• Journal of Information Technology Services
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• v.11 no.sup
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• pp.41-50
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• 2012

With the recent advances in smart grid technologies and the increasing dissemination of smart meters, the power usage of each time unit can be detected in modern smart building environments. Thus, the utility company can adopt different price of electricity at each time slot considering the peak time. Korea government also announces the smart-grid roadmap that includes a law for realtime price of electricity. In this paper, we propose an efficient power scheduling scheme for smart buildings that adopt smart meters and real-time pricing of electricity. Our scheme dynamically changes the power mode of each consumer device according to the change of power rates. Specifically, we analyze the electricity demands and prices at each time, and then perform real-time power scheduling of consumer devices based on collaboration of each device. Experimental results show that the proposed scheme reduces the electricity charge of a smart building by up to 36.4%.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.10
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• pp.117-124
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• 2017

A Smart Grid is a system that can efficiently use energy by exchanging real-time information in both directions between a consumer and a power supplier using ICT technology on an existing power network. DR(Demand response) is an arrangement in which electricity users can sell the electricity they save to the electricity market when the price of electricity is high or the power system is crisis. In this study, we developed a power meter data transmission device and power IT system that measure the demand information in real-time using a smart meter and transmit it to a cloud server. The power meter data transmission device developed in this study uses alight sensor connected to a Raspberry Pi 3 to measure the number of blinking lamps on the KEPCO meter per unit of power, in order to provide reliable data without any measurement errors with respect to the KEPCO power data. The power measurement data transmission device uses the standard communication protocol, OpenADR 2.0b. The measured data is transmitted to the power IT system, which consists of the VEN, VTN, and calculation program, via the LTE WiFi communication network and stored in its MySQL DB. The developed power measurement data transmission device issues a power supply instruction and performs a peak reduction DR when a power system crisis occurs. The developed power meter data transmission device has the advantage of allowing the user to adjust it every 1 minute, where as the existing smart metering time is fixed at once every 15 minutes.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.11 no.2
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• pp.1250-1264
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• 2017

This paper presents the architecture design, implement, experimental validation of a bistatic backscatter wireless communication system in Wi-Fi network. The operating principle is to communicate a tag's data by detecting the power level of the power modulated Wi-Fi packets to be reflected or absorbed by backscatter tag, in interconnecting with Wi-Fi device and Wi-Fi AP. This system is able to provide the identification and sensor data of tag on the internet connectivity without requiring extra device for reading data, because this uses an existing Wi-Fi AP infrastructure. The backscatter tag consists of Wi-Fi energy harvesting part and a backscatter transmitter/a power-detecting receiver part. This tag can operate by harvesting and generating energy from Wi-Fi signal power. Wi-Fi device decodes information of the tag data by recognizing the power level of the backscattered Wi-Fi packets. Wi-Fi device receives the backscattered Wi-Fi packets and generates the tag's data pattern in the time-series of channel state information (CSI) values. We believe that this system can be achieved wireless connectivity for ultra- low-power IoT and wearable device.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.3
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• pp.35-41
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• 2018

Smart device has become an affordable main computing resource for robotic ap-plications in accordance with a fast growth of mobile internet environment. Since the computing power of smart device has been increased, smart device based ro-bot system attempts to replace traditional robot applications with laptop-based system. Methodologies for acquisition of remote sensory information and control of various types of robots using smart device have been proposed recently. In this paper, we propose a robot control system using a monitoring program and a communication protocol. The proposed system is a combination of an educa-tional programming oriented robot named EPOR-S. as small service robot plat-form and a smart device. Through a simulation study using image processing, the feasibility of combination of the proposed robot monitoring program and control system was verified.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.3
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• pp.133-141
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• 2018

There are increasing interests on smart home systems. However, most of the existing works focus on the functionality itself. In this paper, we propose an extensible smart home system based on low power networking such as CoAP, 6LoWPAN, and Zigbee. The proposed home IoT system consists of Home APP, Home Server, Home Broker, and Power Devices. Each component of the system is connected by the low-power network technologies aforementioned. As the end device, Power Device senses the current consumption of the attached appliance and controls the power to it. Power Device reports the sensing data to Home Server via Home Broker. The Home Broker enhances the scalability of the system. Home Broker extends the service area and the user's services, and it manages the connection of the underlying devices and processes, and transmits data to Home Server from Power Devices. Through the experimental evaluation, we show that the proposed system achieves the design goals such as extensibility and low power networking.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.367-368
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• 2014

This paper investigates characteristics of high power semiconductor device losses in 5MW-class Permanent Magnet Synchronous Generator (PMSG) Medium Voltage (MV) wind turbines. High power semiconductor device of press-pack type IGCT of 6.5kV is considered in this paper. Analysis is performed based on neutral point clamped (NPC) 3-level back-to-back type voltage source converter (VSC) supplied from grid voltage of 4160V. This paper describes total loss distribution at worst case under inverter and rectifier operating mode for the power semiconductor switches. The loss analysis is confirmed through PLECS simulations. In addition, the loss factors due to di/dt snubber and ac input filter are presented. The investigation result shows that IGCT type semiconductor devices generate the total efficiency of 97.74% under the rated condition.

• International Journal of Internet, Broadcasting and Communication
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• v.10 no.2
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• pp.7-12
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• 2018

The spread of IoT (Internet of Things) technology that connects objects based on wired / wireless networks is accelerating, and IoT-based smart home technology that constitutes a super connected network connecting sensors and home appliances existing inside and outside the home is getting popular. In addition, demand for alternative energy technologies such as photovoltaic power generation is rapidly increasing due to rapid increase of consumption of energy resources. Recently, small solar power systems for general households as well as large solar power systems for installation in large buildings are being introduced, but they are effectively implemented due to limitations of small solar panels and lack of power management technology. In this paper, we have studied smart home structure and IoT / IoL device discovery algorithm for energy harvesting system based on photovoltaic power generation, It is possible to construct an efficient smart home system for device control.