• Tribology and Lubricants
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• v.13 no.2
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• pp.27-38
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• 1997

ER clutch is a device using ER fluid, so called "intelligent material" and is a power transmission system controlled with electric field strength. This device responses very rapidly when controlled by rapid and continuous electrical signal and can form a servosystem. Wear, noise and vibration during operation is very low level. This study was undertaken to investigate substitutive possibilities of this ER clutch for existing power transmission mechanism. An analytic relationships using rheological model (so called, 'Bingham plastic model') of ER fluid were developed, and operation constraints and optimum design concepts were constructed. With this relationships, typical responses of ER clutch and effects of changing geometric, kinetic parameters of ER clutch and ER fluid properties were described. In conclusion, compared with existing mechanisms, an excellent performance of ER clutch was confirmed.confirmed.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.805-808
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• 2005

In this study, the design of advanced LVDS(Low Voltage Differential Signaling) I/O interface circuit with new structural low triggering ESD(Electro-Static Discharge) protection circuit was investigated. Due to the differential transmission technique and low power consumption at same time. maximum transmission data ratio of designed LVDS transmitter was simulated to 5Gbps, Also, the LIGCSCR(Latch-up Immune Gate Coupled SCR)was designed. It consists of PLVTSCR (P-type Low Voltage Trigger SCR), control NMOS and RC network. The triggering voltage was simulated to 3.6V. And the latch-up characteristics were improved. Finally, we performed the layout high speed I/O interlace circuit with the low triggered ESD protection device in one-chip.

• The Magazine of the IEIE
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• v.37 no.8
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• pp.50-59
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• 2010

$0.18-{\mu}m$ high voltage technology 13.5V high voltage well-based symmetric EDMOS isolated by MTI was designed and fabricated. Using calibrated process and device model parameters, the characteristics of the symmetric and asymmetric EDMOS have been simulated. The asymmetric EDMOS has higher performance, better $R_{sp}$ / BVDSS figure-of-merit, short-channel immunity and smaller pitch size than the symmetric EDMOS. The asymmetric EDMOST is a good candidate for low-power and smaller source driver chips. The low voltage logic well-based EDMOS process has advantages over high voltage well-based EDMOS in process cost by eliminating the process steps of high-voltage well/drift implant, high-temperature long-time thermal steps, etc. The specific on-resistance of our well-designed logic well-based EDMOSTs is compatible with the smallest one published. TCAD simulation and measurement results show that the improved logic well-based nEDMOS has better electrical characteristics than those of the conventional one. The improved EDMOS proposed in this paper is an excellent candidate to be integrated with low voltage logic devices for high-performance low-power low-cost chips.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.11 no.4
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• pp.109-116
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• 1997

This paper describes the surge protective device combined with varistor and LC low pass filter on AC power circuits. Up to now varistors alone have been used as a surge protective device on AC power circuits, but it gives negative effects on the equipments to be protected due to the steep rise and high remnant voltage. Therefore in this work, for the purpose of improving the cutoff performance of surge protective device on AC power circuits, the hybrid-type surge protective device with varistor and LC filter was designed and prepared. And the experiments for operational characteristics and clamping performance of the surge protective device were carried out with an 1.2/50[$\mu$s] impulse generator. As a result, the proposed surge protective device with the combination of varistors and LC filter can limit the surge voltage to lower value and reduce the value of dV /dt to very small values. Also the attenuation of high-frequency voltages across the output port is effectively provided by LC filter. Therefore this result may be all the more helpful avoiding both damage and upset of electronic systems.

• Journal of IKEEE
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• v.17 no.3
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• pp.365-370
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• 2013

Power MOSFET is developed in power savings, high efficiency, small size, high reliability, fast switching, and low noise. Power MOSFET can be used in high-speed switching transistors devices. Recently attention given to the motor and the application of various technologies. Power MOSFET is a voltage-driven approach switching device and designed to handle on large power, power supplies, converters, motor controllers. In this paper, the 400 V Planar type, and the trench type for realization of low on-resistance are designed. Trench Gate Power MOSFET Vth : 3.25 V BV : 484 V Ron : 0.0395 Ohm has been optimized.

• KIEE International Transactions on Electrophysics and Applications
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• v.4C no.3
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• pp.101-105
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• 2004

The efficient power MOSFET inverter applied for a simple and low cost power supply is proposed for driving the dielectric barrier discharge (DBD) lamp load. For decades, the DBD phenomenon has been used for ozone gas production in industry. In this research, the ultraviolet and visible light sources utilizing the DBD lamp is considered as the load for solid-state high frequency power supply. It is found that the simple voltage-source single-ended quasi-resonant ZVS inverter with only one active power switch could effectively drive this load with the output power up to 700 W. The pulse density modulation based control scheme for the single-ended quasi-resonant ZVS inverter using a low voltage and high current power MOSFET switching device is proposed to provide a linear power regulation characteristic in the wide range 0-100％ of the full power as compared with the conventional control based Royer type parallel resonant inverter type power supplies.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.12
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• pp.1654-1661
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• 2020

Internet of Things(IoT) technology can remotely collect and control a sensing information of device by attaching a small communication device to equipment that does not support communication. Low-Power Wide-Area Network (LPWAN), a low-power, long-distance communication technology, was proposed to support IoT technology, and Long Range(LoRa) is representative. Various systems, including network device, can collect and control the status information of device in real time through remote access. However, when a network failure occurs, remote access and status monitoring are impossible unless there is a separate additional network. To overcome this problem, in this paper, we propose an independent remote device management system that can be easily attached to device, which monitors and controls equipment remotely using an independent network. We will design and implement the proposed system, via which we will show its practicality and expandability.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.17 no.1
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• pp.213-218
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• 2017

High-voltage power systems operate in order to generate and transmit electric power at power stations. Compared to low-power systems, high-power systems are complex in structure, large-scale, and expensive. When high-power cable accidents occur, most facilities are incapacitated-including low-power systems-causing huge economic losses. Great care must therefore be taken in designing, installing and managing power systems. Although dependent on installation circumstances and usage conditions, in some cases the cross-sectional areas of cables fall short of the critical area due to the expansion of and improper design and installation of power facilities. In this situation, the exceeded ampacity (allowable current) above the critical value caused by the operating current initiates the deterioration processes of power cables. In order to systematically monitor power cables operating at power stations, we have developed the first device of its kind in Korea. In this paper, we present the analyzed characteristics of expected temperatures of cables based on the load current of high-voltage cables operating at Korean Western Power Co. Ltd. We can predict the lifetime of cables by analyzing the temperature obtained from our device.

• Journal of Biosystems Engineering
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• v.28 no.4
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• pp.295-304
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• 2003

In this study, a rotary equipped with devices for preventing alien substance from being wound and for preventing soil adherence were developed and their performances are evaluated in the field. The former device was effective in the paddy field with low moisture content, but power requirement of rotary tilling was increased in the field with high moisture content. In the field test of rotaries equipped with device to prevent the power requirements were measured to be 52.18, 52.44, 49.01 and 46.34 PS for general, stainless steel, rubber and PE rotaries, and the quantities of the soil adhered to rotaries, on the average, were to be 5.6, 5.7, 3.1 and 2.7 kg for general, stainless steel, rubber and PE rotaries, respectively. The PE rotary cover reduced the power requirement and soil adherence by 11 and 52%, respectively.