• Journal of Drive and Control
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• v.11 no.4
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• pp.39-45
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• 2014

With recent oil price increases, the fuel efficiency of hydraulic excavators has become a serious issue. Researchers have considered weight lightening by high pressurization in order to improve the efficiency of the excavator and pump controlled actuation (PCA) and to reduce pressure loss of hybrid and valves using mechanical inertia. However, high pressurization is not very effective because the excavator operates at a low speed; a hybrid is inefficient because little accumulated inertial energy is accumulated; and PCA is ineffective because control precision and responsibility are low. In this study, a method to minimize air and gas in hydraulic oil has been presented as a simple and new way to increase hydraulic efficiency.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.444-444
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• 2008

EL은 LCD와 같은 수광 형태의 소자에 비해 응답속도가 빠르고, 자체 발광 형태의 디스플레이로 휘도가 우수하며 구조가 간단하여 제조가 용이하고 경량 박형의 장점을 가지고 있다. EL을 이용하여 세븐 세그먼트나 픽셀별 발광으로 표시소자를 제작하였다. EL 소자의 구조는 전극은 금, 유전체는 PMN과 PZT를 이용하였으며 형광체를 적층하고 ITO를 증착하여 제작하였다. 4*4mm로 크기의 픽셀이 49개가 들어간 소자를 제작하고 ITO와 하부 전극을 교차하여 매트릭스 타입으로 제작하였다. 픽셀 하나에 교류 전압 펄스를 변화하여 가했을 때의 픽셀의 광전특성과 주변 픽셀에 미치는 영향에 대해 오실로스코프, 광 프로브 등을 이용하여 특성을 살펴보았다.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1044-1046
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• 2009

Here we report the architecture for a non-volatile n-type memory paper field-effect transistor. The device is built using the hybrid integration of natural cellulose fibers (pine and eucalyptus fibers embedded in an ionic resin), which act simultaneously as substrate and gate dielectric, with amorphous GIZO and IZO oxides as gate and channel layers, respectively. This is complemented by the use of continuous patterned metal layers as source/drain electrodes.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1143-1145
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• 2000

In this paper, it presents the design and implementation of a Microstep control IC using Programmable Logic Device(PLD). A Microstep driver is implemented with a 5-phase hybrid stepping motor, which has a Pentagon winding, power MOSFETs, and some devices to improve the system characteristics. The Microstep driving method is used for high performance motion control, low vibration and low noise in motor control system. The improvement of the electrical and mechanical driving characteristic of a step motor is achieved by applying microstep driver.

• Proceedings of the Korean Society of Computer Information Conference
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• 2014.07a
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• pp.67-70
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• 2014

최근의 다양한 환경에서 악성코드나 의심 코드에 의한 피해가 날로 늘어나고 있는 추세이며 이를 종합적으로 대응할 수 있는 시스템에 대한 연구가 활발히 이루어지고 있는 상황이다. 이러한 악성코드는 사용자의 동의 없이도 PC에 설치되어 사용자가 인지하지 못하는 피해를 지속적으로 영산하고 있으며 그 심각성도 날로 심해지고 있는 실정이다. 또한 다양한 시스템으로부터 수집되는 방대한 양의 데이터를 실시간으로 처리하고 검증하는 기술 및 탐지 기법을 토대로 악성코드를 탐지하고 분석할 수 있는 대응기술로 고도화 되어야만 한다. 이러한 악성코드는 사용자의 PC에 설치되기 이전부터 검사 및 판단하여 사전 대응하는 것이 매우 중요하다. 본 논문에서는 이러한 악성코드가 실제 PC상에 설치되기 이전에 탐지할 수 있는 기법을 제시하며 이를 장치형태로 검증하였다. 본 논문에서 제시하는 기술을 토대로 악상코드 근절에 대한 근본적인 대안을 제시할 것이라 판단한다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.392-395
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• 2010

최소질량형 제진장치는 초고층건물의 풍진동 제어시 질량체의 관성력을 최대한 효율적으로 이용하여 이동질량의 크기를 최소화한 제진장치라 할 수 있다. 본 연구의 최종목표는 순수 국내기술에 의한 능동제어(active control)와 수동제어(passive control)의 특성이 결합된 하이브리드 제진장치(hybrid control device)의 콘트롤러 설계기술 개발이다. 이를 위한 1차적인 목표로 여기에서는 국내에 설치된 기존의 능동진동제어장치의 전체적인 설계과정을 살펴본다.

• Proceedings of the KIEE Conference
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• summer
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• pp.923-925
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• 2004

A lot of conventional automotive components driven by mechanical power source are being replaced with electrical ones to comply with the demands of market and customer, therefore the amount of electric energy used in a vehicle will be increased continuously. The increment of electric power demand causes interest on new higher power system such as 42V Power Net, and furthermore necessity for development of energy storage device is highlighted recently. This paper present the design of the BLDC motor for electric air-conditioner in 42V system and compare with the characteristics of several type BLDC motor.

• Proceedings of the KIEE Conference
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• 2003.07b
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• pp.798-800
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• 2003

Recently, in optical storage device technical trends, the size of optical drive is slimmer to adopt notebook computer and the power of actuator is higher to achieve the high transfer rate. However, these trends of optical disc drives tend to increase the temperature of the actuator part, it causes some problems on the performance of optical parts - the resonance frequency of the actuator is down to lower band and the objective lens, coil and magnet are easily damaged. In this study, to overcome these thermal problems, the numerical simulations of heat transfer were performed. As the result of simulations, the thermal characteristic of the hybrid actuator is better than the previous design. And, it shows the good dynamic performance in experiment.

• Proceedings of the KIEE Conference
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• 2009.04b
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• pp.94-96
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• 2009

This paper deals with the design considerations of electro-magnet (EM)-permanent magnet (PM) hybrid levitation and propulsion device for magnetically levitated (maglev) vehicles. Several design considerations such as machine structure, manufacturing, and control strategy are described. In order to verify the design scheme and feasibility of control strategy, dynamic test set is implemented and tested.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.580-583
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• 2006

A small-scale solar concentrating system was developed and demonstrated for supplying process heat required in solar thermo chemical reaction. The concentration system consists of a heliostat equipped with a solar tracking device and a dish concentrator. From the initial thermal test of the concentrating system it was found that the system works very well with around 500-600 concentration ratio capable of supplying about 3kW therml energy to the reactor. Once the concentration system was turned on, the reactor temperature rapidly increased over $1,000^{\circ}C$ and could be maintained high enough for solar chemical reaction.