• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 전력전자학술대회 논문집
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• pp.411-412
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• 2014

In this paper, the switching losses and performances of Silicon Carbide(SiC) and Silicon based on the MOSFETs have been compared. To do this experiment, the buck converter using both SiC and Si devices have been built and tested. As a result, it has been confirmed that the converter with SiC devices shows better efficiency and performance compared with the converter using Si devices.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.589-590
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• 2013

The fast development of electronic devices towards wireless, portable and multi-functionality desperately needs the self-powered and low maintenance power sources. The possibility to coupling the nanogenerator to wearable and portable electronic device facilitates the self powered device with independent and self sustained power source. Nanogenerator has ability to convert the low frequency mechanical vibration to electrical energy which is utilized to drive the electronic device [1]. The self powered power source has the ability to generate the power from environment and human activity has attracted much interest because of place and time independent. The human body motion based energy harvesting has created huge impact for future self powered electronics device applications. The power generated from the human body motion is enough to operate the future electronic devices. The energy harvesting from human body motion based on triboelectric effect has simple, cost-effective method [2, 3] and meet the required power density of devices. However, its output is still insufficient to driving electronic devices in continues manner so new technology and new device architecture required to meet required power. In the present work, we have fabricated the triboelectric nanogenerator using PDMS polymer. We have studied detail about the power output of the device with respect to different polymer thickness and varied separation distance.

• 전기학회논문지
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• 제58권1호
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• pp.63-68
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• 2009

As the complexity of the power system becomes higher, tests of the new devices, such as exciter and PCS(Power Conversion System) of the distributed generation sources, in the real operating condition are more important. However tests of the unverified devices in the real power system may cause hazardous malfunction of the system. In order to avoid this problem, power devices may be tested with the real-time simulators instead of the real power system. This paper presents an real-time multi machine power system simulator using PCs(Personal Computer) and Fast Ethernet. Developed real-time simulator performs the electro-mechanical dynamic simulation of multi-machine power system by the network distributed computing technique. Because the simulator consists of usual PCs and Fast Ethernet, it is possible to make up a simulation system very cheaper than the conventional real-time simulator which consists of dedicated expensive hardware devices. The performance of the developed simulator is tested and verified with the scaled model excitation system. The test which adjust the control parameters of the exciter is performed with the well-known New England 10 generator 39 bus sample power system.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권7호
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• pp.3351-3369
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• 2017

In recent years, datacenters, network devices and computers have proliferated. The power consumed by information and communication technology (ICT) devices has inflated in an extraordinary manner. Green communication has emerged as a new approach to reduce and optimize power consumption in ICT sector. Many methods and protocols have been proposed and implemented to achieve green communication. Nevertheless, the increase of power consumption remains a problem. In this work, we attempt to reduce and optimize power consumption of network devices in datacenters environment utilizing software defined network (SDN) paradigm. To gain more insight of the power consumption requirements of network switches, a power measurement system is constructed to measure power consumption levels of network devices. Subsequently, we propose a duplication resolver algorithm (DRA) to power off/on switches reactively. DRA algorithm reduces the required time by switches to construct their flow tables after rebooting. To this end, DRA-based external circuit has been constructed utilizing Ethernet module and an Arduino kit to control power supplies of network devices. To facilitate our work, a testbed has been constructed utilizing Ryu SDN controller, HP2920-24G switches and Arduino kits. Our results show that DRA algorithm can reduce both the power usage and start-up time delay of network switches after failures.

• 한국전기전자재료학회논문지
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• 제26권3호
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• pp.190-193
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• 2013

Power MOSFET and Power IGBT is develop in power savings, high efficiency, small size, high reliability, fast switching, low noise. Power MOSFET can be used high-speed switching transistors devices. Power MOSFET is devices the voltage-driven approach switching devices are design to handle on large power, power supplies, converters. In this paper, design the 80V MOSFET Planar Gate type, and design the Trench Gate type for realization of low on-resistance. For both structures, by comparing and analyzing the results of the simulation and characterization.

• Journal of Information Processing Systems
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• 제15권3호
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• pp.593-603
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• 2019

In wearable healthcare systems, sensor devices can be deployed in places around the human body such as the stomach, back, arms, and legs. The sensors use tiny batteries, which have limited resources, and old sensor batteries must be replaced with new batteries. It is difficult to deploy sensor devices directly into the human body. Therefore, instead of replacing sensor batteries, increasing the lifetime of sensor devices is more efficient. A transmission power control (TPC) algorithm is a representative technique to increase the lifetime of sensor devices. Sensor devices using a TPC algorithm control their transmission power level (TPL) to reduce battery energy consumption. The TPC algorithm operates on a closed-loop mechanism that consists of two parts, such as sensor and sink devices. Most previous research considered only the sink part of devices in the closed-loop. If we consider both the sensor and sink parts of a closed-loop mechanism, sensor devices reduce energy consumption more than previous systems that only consider the sensor part. In this paper, we propose a new approach to consider both the sensor and sink as part of a closed-loop mechanism for efficient energy management of sensor devices. Our proposed approach judges the current channel condition based on the values of various body sensors. If the current channel is not optimal, sensor devices maintain their current TPL without communication to save the sensor's batteries. Otherwise, they find an optimal TPL. To compare performance with other TPC algorithms, we implemented a TPC algorithm and embedded it into sensor devices. Our experimental results show that our new algorithm is better than other TPC algorithms, such as linear, binary, hybrid, and ATPC.

• 디지털융복합연구
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• 제18권12호
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• pp.543-548
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• 2020

본 연구는 다중의 동력장치를 이용하여 다수의 객체를 움직이는 키네틱 디자인작품을 제작하면서 다수의 객체를 소수의 동력장치를 이용하여 다수의 동력장치를 이용한 것 같은 다양한 움직임을 구현할 수 있게 하는 것이 목적이다. 다수의 객체를 다양하게 움직이기 위해선 다수의 동력장치를 사용하여 움직임을 나타내는 것이 일반적인 방법이나 이렇게 하면 객체만큼의 많은 동력장치를 이용해야 하며 과다한 동력장치 사용으로 비용의 상승과 작품무게가 증가하게 된다. 많은 동력장치를 움직이기 위한 많은 전력 소모를 하게 된다. 이에 소수의 동력장치로 다수의 객체를 다양한 움직임을 통해 제어할 수 있는 메커니즘을 작품에 적용하여 실험하였다. 메커니즘을 이용해 다수의 객체를 움직이면 작품의 무게와 전력 소모량을 현저하게 줄일 수 있었다. 또한, 캠의 위치와 모양을 변경한 캠샤프트 구조의 이용과 베벨기어의 이용을 통해 객체의 행과 열을 늘려 다양한 움직임을 표현할 수 있었다. 본 연구를 통해 키네틱 디자인 작품을 제작하는 많은 디자이너에게 다수의 객체를 제어하는 하나의 또 다른 방법을 제시하게 된다.

• 한국정보통신학회논문지
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• 제9권2호
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• pp.289-294
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• 2005

본 논문은 변전소내 정보기기에 나타나는 서지전압 전류의 측정 결과에 대해 기술하였다. 서지전압 전류 관측을 위한 전력분석기는 전력용 변압기와 개폐기 주변의 신호선에 설치하였으며, 전력분석기의 시간분해능은 4 MS/s이다. 측정된 서지전압.전류의 크기는 각각 500~1,300v와 500~3,100k 이었으며, 측정기간 동안 평균 5~10회/일 이상의 서지가 기록되었다. 따라서 고전압 전력설비 주변에 설치되는 정보기기는 설치환경에 나타나는 서지의 크기를 고려하여 설계되어야 할 것이다.

• Journal of Power Electronics
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• 제13권2호
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• pp.313-321
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• 2013

This paper describes the operation analysis results of a communication-based DC micro-grid using a hardware simulator developed in the lab. The developed hardware simulator is composed of distributed generation devices such as wind power, photovoltaic power and fuel cells, and energy storage devices such as super-capacitors and batteries. Whole system monitoring and control was implemented using a personal computer. The power management scheme was implemented in a main controller based on a TMS320F28335 chip. The main controller is connected with the local controller in each of the distributed generator and energy storage devices through the communication link based on a CAN or an IEC61850. The operation analysis results using the developed hardware simulator confirm the ability of the DC micro-grid to supply the electric power to end users.

• Journal of Information Processing Systems
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• 제9권1호
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• pp.41-52
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• 2013

One of the obstacles preventing the Zigbee protocol from being widely used is the excessive power consumption of Zigbee devices in low bandwidth and low power requirement applications. This paper proposes a protocol that resolves the power efficiency problem. The proposed protocol reduces the power consumption of Zigbee devices in beacon-enabled networks without increasing the time taken by Zigbee peripherals to communicate with their coordinator. The proposed protocol utilizes a beacon control mechanism called a "sleep pattern," which is updated based on the previous event statistics. It determines exactly when Zigbee peripherals wake up or sleep. A simulation of the proposed protocol using realistic parameters and an experiment using commercial products yielded similar results, demonstrating that the protocol may be a solution to reduce the power consumption of Zigbee devices.