• The Journal of Korea Robotics Society
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• v.10 no.2
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• pp.119-132
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• 2015

Two novel parallel mechanisms (PMs) employing two or three PaPaRR subchains are suggested. Each of those two PMs has translational 3-DOF motion and employs only revolute joints such that they could be adequate for haptic devices requiring minimal frictions. The position analyses of those two PMs are conducted. The mobility analysis, the kinematic modeling, and singularity analysis of each of two PMs are performed employing the screw theory. Then through optimal kinematic design, each of two PMs has excellent kinematic characteristics as well as useful workspace size adequate for haptic applications. In particular, by applying an additional redundantly actuated joint to the 2-PaPaRR type PM which has a closed-form position solution, it is shown that all of its parallel singularities within reachable workspace are completely removed and that its kinematic characteristics are improved.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.4
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• pp.325-332
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• 2017

The engine cooling system is a device that maintains the temperature in the engine room at an appropriate level by driving a cooling fan when the temperature in the engine room generated during the vehicle operation occurs over a certain temperature. In recent years, the vehicle cooling system has changed to an electronic system. Therefore, in this paper, we design and develop a hall sensor based electronic engine cooling system. In this paper, a hall sensor module and an actuator module for engine cooling control system are designed. In order to verify the performance of the designed module, the magnetic field control was verified through the simulation of the diameter and the head of the coil.

• 제어로봇시스템학회:학술대회논문집
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• 1994.10a
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• pp.334-339
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• 1994

In this work, we propose a planar three degree-of-freedom parallel mechanism as another type of assembly device which utilized joint compliances. These joint compliances can be adjusted either by properly replacing the joint compliances or by actively controlling stiffness at joints, in order to generate the desired operational compliance characteristics at RCC point, The operational compliance matrix for this mechanism is explicitly obtained by symbolic manipulation and its operational compliance characteristics are examined, it is found that the RCC point exists at the center of the workspace when the mechanism maintains symmetric configurations. Compliance characteristic and its sensitivity of this mechanism is analyzed with respect to the magnitude of the diagonal compliance components and two different matrix norms measuring compliance sensitivity. It is expected that the analysis results provide the designer with a helpful information to determine a set of optimal parameters of this RCC mechanism.

• Publications of The Korean Astronomical Society
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• v.16 no.1
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• pp.43-47
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• 2001

We developed a CCD camera that can observe wide fields on the sky. We tested the field of views using various lenses. For cooling the CCD chip, we used a thermoelectric cooling device and tested the cooling efficiency. This camera will continuously observe a part of the sky. The data from the camera will be used to decide the current weather condition by the real-time star counting program (SCount) which will be developed later.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2011.05a
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• pp.116-118
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• 2011

현재 차량 내부의 통신 장비는 CAN 통신 방식이 주류를 이루고 있다. 그러나 미래의 자동차 내부의 통신 방식은 보다 고속이고 이중화를 지원하는 FlexRay 방식으로 발전될 것으로 예상되다. 본 논문에서는 차량 내부의 백본으로 사용할 수 있고, 차량 내부의 정보를 FlexRay 기반으로 정보를 전달하고 기록할 수 있는 장치를 개발하여 차량 내부의 정보를 보다 고속이고 안정적으로 정보를 전달할 수 있는 보다 지능화된 시스템을 제시하고 한다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.5
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• pp.53-59
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• 2020

This paper describes the design of a remote control device that can control the ON/OFF state of multiple air compressors using wireless communication. The main remote controller and air compressor remote controller were designed using a microprocessor (ATmega128), and the circuit diagram was configured to wirelessly communicate using A Zigbee module between the two remote controllers. The result of the measurement of wireless communication distance between the two remote controllers was more than 1.1 km.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.552-553
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• 2012

현재의 발전소 내부에 가동 중인 열교환기 배관 라인의 Clinker Monitoring System은 초고온의 열교환기 내부의 벽면 및 배관라인의 클링커 상태를 감시하는 시스템을 요구하고 있다. 이러한 열교환기 내부의 상태를 감시하기 위하여 초고온에 견딜 수 있고 회전이 가능한 장치를 열교환기 내부에 투입하여 회전 가능한 장치를 통하여 원격으로 영상을 전송하도록 하여 클링커 상태를 영상으로 모니터링 하여 열교환기 내부의 상태를 감시 관찰 분석할 수 있는 시스템을 구성하였다. 본 논문에서는 발전설비의 열교환기 내부의 클링커 상태를 모니터링 할 수 있도록 회전 가능한 렌즈 튜브와 보호용 냉각 시스템을 추가된 통합 모니터링 시스템을 제기하고자 한다.

• Journal of Korean Foot and Ankle Society
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• v.1 no.2
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• pp.81-88
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• 1997

The arthroscopic ankle arthrodesis is one of the good method of the ankle arthrodesis. Mechanical distraction of tibiotalar joint is an absolute necessity for adequate visualization and operative instrumentation. However, there are several disadvantages. Thus we performed arthroscopic ankle arthrodesis using calcaneal traction in three cases and achieved following results. 1. The procedure is easy and the operation time is shorter than the other arthroscopic ankle arthrodesis. 2. The risk of neurovascular damage and infection is reduced by using calcaneal traction. 3. It does not require the expensive distraction device. 4. The adequate visualization for operative instrumentation is obtained.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2525-2527
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• 2000

The analysis of distribution line faults is essential to the proper protection of power system. A high impedance fault(HIF) dose not make enough current to cause conventional protective device operating, so it is well known that undesirable operating conditions and certain types of faults on electric distribution feeders cannot be detected by using conventional protection system. In this paper, we prove that the nature of the high impedance faults is indeed a deterministic chaos, not a random motion. Algorithms for estimating Lyapunov spectrum and the largest Lyapunov exponent are applied to various fault currents detections in order to evaluate the orbital instability peculiar to deterministic chaos dynamically, and fractal dimensions of fault currents which represent geometrical self-similarity are calculated. Wavelet transform analysis is applied the time-scale information to fault signal. Time-scale representation of high impedance faults can detect easily and localize correctly the fault waveform.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.311-311
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• 2013

The resistance switching memory devices have several advantages to take breakthrough for the limitation of operation speed, retention, and device scale. Especially, the metal-oxide materials such as ZnO are able to fabricate on the flexible and visible transparent plastic substrate. Also, the quantum dots (QDs) embedded in dielectric layer could be improve the ratio between the low and the high resistance becauseof their Coulomb blockade, carrier trap and induced filament path formation. In this study, we irradiated 0.2-MeV-electron beam on the ZnO/QDs/ZnO structure to control the defect and oxygen vacancy of ZnO layer. The metal-oxide QDs embedded in ZnO layer on Pt/glass substrate were fabricated for a memory device and evaluated electrical properties after 0.2-MeV-electron beam irradiations. To formation bottom electrode, the Pt layer (200 nm) was deposited on the glass substrate by direct current sputter. The ZnO layer (100 nm) was deposited by ultra-high vacuum radio frequency sputter at base pressure $1{\times}10^{-10}$ Torr. And then, the metal-oxide QDs on the ZnO layer were created by thermal annealing. Finally, the ZnO layer (100 nm) also was deposited by ultra-high vacuum sputter. Before the formation top electrode, 0.2 MeV liner accelerated electron beams with flux of $1{\times}10^{13}$ and $10^{14}$ electrons/$cm^2$ were irradiated. We will discuss the electrical properties and the physical relationships among the irradiation condition, the dislocation density and mechanism of resistive switching in the hybrid memory device.