• Proceedings of the KIEE Conference
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• 2005.10b
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• pp.264-266
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• 2005

Recently, on-line diagnosis methods through wired and wireless networks are widely adopted in the diagnosis of industrial Electric Facilities, such as generators, transformers and motors. Also smart sensors which includes sensors, signal conditioning circuits and micro-controller in one board are widely studied in the field of condition monitoring. This paper suggests an self-powered system suitable for condition-monitoring smart sensors, which uses parasitic vibrations of the facilities as energy source. First, vibration-driven noise patterns of the electric facilities are presented. And then, an electromagnetic generator which uses mechanical mass-spring vibration resonance are suggested and designed. Finally energy consumption of the presented smart sensor, which consists of MEMS vibration sensors, signal conditioning circuits, a low-power consumption micro-controller, and a ZIGBEE wireless tranceiver, are presented. The usefulness and limits of the presented electromagnetic generators in the field of electric facility monitoring are also suggested.

• Journal of the Korean Vacuum Society
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• v.18 no.5
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• pp.390-393
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• 2009

We report on a new patterning technique for organic functional materials applicable to organic photovoltacis (OPVs). The unconventioal patterning technique, $O_2$ plsama-etching selectively perfluoro-alkyl fluorosilanes, is used for producing a bulk-heterojunction active layer with poly(3-hexylthiophene) as the electron donor and [6,6]-phenyl-$C_{61}$ butyric acid methyl ester as the electron acceptor. The patterning with reduced leakage path and parasitic capacitance suggests a way for fabrication of OPVs with higher energy conversion efficiency.

• Journal of the Korean Institute of Telematics and Electronics
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• v.27 no.4
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• pp.534-540
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• 1990

In this paper the characteristics of submicron gate GaAs MESFET's have been studied using a particle model which takes into account the hot-electron transport phenomena, i.e., the velocity overshoot. \ulcornervalley(<000> direction), L valley (<111>direction), X valley (<100>direction) as the GaAs conduction energy band and optical phonon, acoustic phonon, equivalent intervalley, nonequivalent intervalley scattering as the scattering models, have been considered in this simulation. And the GaAs material and the device simulation have been done by determination of the free flight time, scattering mechanism and scattering angle according to Monte-Carlo algorithm which makes use of a particle model. As a result of the particle simulation, firstly the electron distribution, the potential energy distribution and the situation of electron displacement in 0.6 \ulcorner gate length device have been obtained. Secondly, the cutoff frequency, obtained by this method, is k47GHz which is in good agreement with the calculated result of theory. And the current-voltage characteristics curve which takes account of the buffer layer effect has been obtained. Lastly it has been verified that parasitic current at the buffer layer can be analyzed using channel depth modulation.

• Journal of Institute of Control, Robotics and Systems
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• v.22 no.6
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• pp.389-396
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• 2016

The sealing robot must be able to calculate the slope of a contact surface for complete adherence of the sealing on different concrete shapes. After the slope is obtained, the robot will track on the surface of the concrete, but this process contains an error in the actual purpose of the force command. The reason this a phenomenon occurs, the non-linearity of the contact surface and the end-effector, is due to parasitic coupling. Errors like make it difficult to measure accurately the respective factors. Therefore, it is regarded as a disturbance that occurs when it follows the work surface it. In this paper, we selected the friction coefficient of the surface as a control factor and designed a compensator to reduce effects of disturbance. Finally, in view of the non-linearity of the end-effector of a robot to contact surfaces directly, we propose a robust force tracking controller in the finite range for managing disturbances that occur during the sealing.

• Journal of Power Electronics
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• v.16 no.1
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• pp.153-162
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• 2016

Given their structural arrangement, photovoltaic (PV) modules exhibit parasitic capacitance, which creates a path for high-frequency current during zero-state switching of the converter in transformerless systems. This current has to be limited to ensure safety and electromagnetic compatibility. Many solutions that can minimize or completely avoid this phenomenon, are available. However, most of these solutions are patented because they rely on specific and often complex converter topologies. This study aims to solve this problem by introducing a solution based on a classic converter topology with an appropriate modulation technique and passive filtering. A 5.5 kW single-phase residential PV system that consists of DC-DC boost stage and DC-AC H-bridge converter is considered. Control schemes for both converter stages are presented. An overview of existing modulation techniques for H-bridge converter is provided, and a modification of hybrid modulation is proposed. A system prototype is built for the experimental verification. As shown in the study, with simple filtering and proper selection of switching states, achieving low leakage current level is possible while maintaining high converter efficiency and required energy quality.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1951-1953
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• 2004

In this study, we propose a small high voltage power supply which use a half-bridge ZCS resonant and Cockroft-Walton on circuit, for ESP (Electrostatic Precipitator). This power supply transfers energy from ZCS resonant inverter to step-up transformer and the transformer secondary is applied to the Cockroft-Walton circuit for generating high voltage as discharging source of electrodes. It is highly efficient because its amount of switching losses are reduced by virtue of the current resonant half-bridge inverter, and also due to the small size, low parasitic capacitance in the transformer stage owing to the low number of winding turns of the step up transformer secondary combined with the Cockroft-Walton circuit. From these results, the best operational condition is obtained at the switching frequency of 9 kHz and the duty ratio of 50 % in this ESP.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.344-345
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• 2011

스마트 그리드 산업으로 인하여 신재생에너지의 활용이 중시되고 있는 시점에서 신재생에너지원을 더욱 효율적이고 안정적으로 사용하기 위해서는 에너지 저장장치의 필요성이 부각되고 있다. 신재생 에너지원을 사용하기 위한 부스트 컨버터와 충방전기를 설계시 일반적으로 시뮬레이션을 통해 설계를 하게 된다. 이때, 인덕터와 커패시터를 이상적인 소자라고 생각하고 시뮬레이션 하거나, 실제 하드웨어와 같이 인덕터와 커패시터에 기생하는 저항을 포함시켜 시뮬레이션을 하게 된다. 본 논문에서는 신재생 에너지원을 계통에 사용할 수 있도록 저전압 상태에서의 신재생 에너지원 출력전압을 승압시켜 인버터를 사용할 수 있도록 만들어 주는 부스트 컨버터의 인덕터를 이상적인 경우와 기생저항이 포함된 경우 각각의 조건하에서 충방전기와 연결하였을 경우 충방전기의 설계에 어떠한 영향을 주는지를 알기 위해 부스트 컨버터의 출력 임피던스 수식을 통해 분석한 MATLAB과 PSIM을 통해 시뮬레이션을 하여 증명하였다.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.137-140
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• 2007

We consider the optimum air flow channel design for DMFC's in the present study. The effect of pressure drop across the inlet and outlet of a stack on the performance of a DMFC is the optimization of such geometric parameters is crucial to minimize the parasitic power usage by the auxiliary devices such as fuel pumps and blowers. In this paper, we present how the pressure drop control can optimize the driving point of a DMFC stack. Further, we show how the optimal fuel utilization ratio can be achieved, not degrading the performance of DMFC stacks. Overall, we discuss how the flow channel design affects the selection of balance of plant(BOP) components, the design of DMFC systems and the system efficiency.

• Parasites, Hosts and Diseases
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• v.48 no.4
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• pp.281-284
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• 2010

Due to the possible emergence of resistance and safety concerns on certain treatments, development of new drugs against parasites is essential for the effective control and subsequent eradication of parasitic infections. Several drug targets have been identified which are either genes or proteins essential for the parasite survival and distinct from the hosts. These include the phosphagen kinases (PKs) which are enzymes that playa key role in maintenance of homeostasis in cells exhibiting high or variable rates of energy turnover by catalizing the reversible transfer of a phosphate between ATP and naturally occurring guanidine compounds. PKs have been identified in a number of important human and animal parasites and were also shown to be significant in survival and adaptation to stress conditions. The potential of parasite PKs as novel chemotherapeutic targets remains to be explored.

• ETRI Journal
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• v.32 no.1
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• pp.166-168
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• 2010

We investigate the possibility of using adiabatic logic as a countermeasure against differential power analysis (DPA) style attacks to make use of its energy efficiency. Like other dual-rail logics, adiabatic logic exhibits a current dependence on input data, which makes the system vulnerable to DPA. To resolve this issue, we propose a symmetric adiabatic logic in which the discharge paths are symmetric for data-independent parasitic capacitance, and the charges are shared between the output nodes and between the internal nodes, respectively, to prevent the circuit from depending on the previous input data.