• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.6
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• pp.573-576
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• 2009

We present a passive flow-rate regulator, capable to compensate inlet pressure variation and to maintain a constant flow-rate for precise liquid control. Deflection of the parallel membrane valves in the passive flowrate regulator adjusts fluidic resistance according to inlet fluid pressure without any external energy. Compared to previous passive flow-rate regulators, the present device achieves precision flow regulation functions at the lower threshold compensation pressure of 20kPa with the simpler structure. In the experimental study, the fabricated device achieves the constant flow-rate of $6.09{\pm}0.32{\mu}l/s$ over the inlet pressure range of $20{\sim}50$ kPa. The present flow-rate regulator having simple structure and lower compensation pressure level demonstrates potentials for use in integrated micropump systems.

• The Journal of Korea Robotics Society
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• v.8 no.3
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• pp.186-196
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• 2013

Since its introduction (e.g., [4, 6]), virtual coupling technique has been de facto way to connect a haptic device with a virtual proxy for haptic rendering and control. However, because of the single dependence on spring-damper feedback action, this virtual coupling suffers from the degraded transparency particularly during contact tasks when large device/proxy-forces are involved. In this paper, we propose a novel virtual coupling technique, which, by utilizing passive decomposition, reduces device-proxy position deviation even during the contact tasks while also scaling down (or up) the apparent inertia of the coordinated device-proxy. By doing so, we can significantly improve transparency between multiple degree of freedom (possibly nonlinear) haptic device and virtual proxy. In other to use passive decomposition, disturbance observer of [3] is adopted to estimate human force with some dead-zone modification to avoid "winding-up" force estimation in the presence of device torque saturation. Some preliminary experimental results are also given to illustrate efficacy of the proposed technique.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.23 no.1
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• pp.27-35
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• 2010

This paper presents the vibration control performance of the smart passive control system to suppress the undesired vibration of the structure subjected to the earthquake loadings. Smart passive control system is the MR damper-based control system augmented with electromagnetic induction(EMI) device which consists of permanent magnets and solenoid coils. According to the Faraday's law of electromagnetic induction, an EMI device produces electrical energy from the mechanical energy due to the reciprocal motions of the structure and provide it to the MR damper. The smart passive control system can be the simple and easy to implement and maintain control system by replacing the feedback control system including sensors, controllers and external power sources of the conventional MR damper-based semiactive control system with the EMI device. The control performance of the smart passive control system is evaluated through the set of shaking table test considering the various historical earthquake loadings.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2868-2872
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• 2007

In this study, a passive control using a boat-tail device is conducted for a three-dimensional car model in ground proximity. We consider various boat-tails and investigate the mechanism of drag reduction by them. By varying the length and slant angle of boat-tail, we obtain drag reductions up to 40%. From the oil-surface flow visualization and hot-wire measurement, the drag reduction by the boat-tail is characterized by the shear-layer instability and reattachment on the boat-tail, forming a small separation bubble at the upstream part of boat-tail surface, resulting in the delay of main separation and drag reduction. At high slant angles, the flow fully separates and drag is nearly same as that of no control.

• Journal of Power Electronics
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• v.2 no.3
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• pp.171-180
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• 2002

New 42-volt automotive electrical systems can provide significant improvements in vehicle performance and fuel economy. It is crucial to provide protection against load dump and other overvoltage transients in 42-volt systems. While advanced active control techniques are generally considered capable of providing such protection, the use of passive transient voltage suppression (TVS) devices as a secondary or supplementary protection means can significantly improve design flexibility and reduce system costs. This paper examines the needs and options for passive TVS devices for 42-volt applications. The limitations of the commonly available automotive TVS devices, such as Zener diodes and metal oxide varistors (MOV), are analyzed and reviewed. A new TVS device concept, based on power MOSFET and thin-film polycrystalline silicon back-to-back diode technology, is proposed to provide a better control on the clamp voltage and meet the new 42-volt specification. Both experimental and modeling results are presented. Issues related to the temperature dependence and energy absorbing capability of the new TVS device are discussed in detail. It is concluded that the proposed TVS device provides a cost-effective solution for load dump protection in 42-volt systems.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.12
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• pp.2805-2810
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• 2010

The Passive Device called SAW Device of the ID Tag or a small sensor that can replace all of MEMS technology Micro Device. When using SAW Device will be able to replace that sensor control the power needed or separate space. Enlarge the scope of this advantage to use as a platform for various SAW Device is required. However, the current SAW Sensor development has many, but SAW Sensor that can leverage the platform's development is sketchy. Therefore, this paper implements SAW Reader can be measured in SAW Device Using an FPGA more simple and efficient Reader platform.

• Journal of the Korean Society of Safety
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• v.32 no.6
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• pp.81-88
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• 2017

This study deals with the optimal design of a hybrid control system composed of a combination of active control system and passive control system for effective seismic performance improvement of two adjacent structures. The proposed hybrid control system adopts a configuration of installing an active control device in one building and connecting two adjacent structures with a passive control device so that the one-side active control force can be bi-directionally applied to both buildings through the passive connecting devices. In order to derive the optimal performance of the proposed system, the design parameters of the passive and active control systems were searched using the genetic algorithm. Numerical simulations of 10-story and 8-story buildings have been performed to verify the effectiveness of the proposed technique. For the purpose of comparison, the conventional independent control system with two identical active control systems being installed separately for each structure was also optimally designed and its seismic response has been evaluated as well. From the comparative results of the two control systems, it is demonstrated that the proposed hybrid control system requires larger control force for its one-side active control device than the conventional independent control system does for each of both-side active devices, but quite less than the total control force required for both-side devices of the independent control system, while maintaining similar seismic performance. Therefore, the proposed system is more economical and reliable than the conventional independent control system with two identical active devices.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11b
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• pp.312-315
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• 2001

Recently organic electroluminescent devices have been intensively investigated for using in full-color flat-panel display. Since the quantum efficiency of electrophosphorescent device decrease rapidly as the luminance increase, it is desirable to operate the electrophosphorescent display with active matrix rather than passive matrix. Here we report the study of driving electrophosphorescent diode with all organic thin film transistor(OTFT). The structure of electrophosphorescent diode is ITO/TPD/BCP:Ir(ppy)$_3$/BCP/Alq$_3$/Li:Al/Al. In OTFT. polymer is used as an insulator and pentacene as an active layer. Detailed performance of the integrated device will be discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.11a
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• pp.312-315
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• 2001

Recently organic electroluminescent devices have been intensively investigated for using in full-color flat-panel display. Since the quantum efficiency of electrophosphorescent device decrease rapidly as the luminance increase, it is desirable to operate the electrophosphorescent display with active matrix rather than passive matrix. Here we report the study of driving electrophosphorescent diode with all organic thin film transistor(OTFT). The structure of electrophosphorescent diode is ITO/TPD/BCP:Ir(ppy)$_3$/BCP/Alq$_3$/Li:Al/Al. In OTFT, Polymer is used as an insulator and pentacene as an active layer. Detailed performance of the integrated device will be discussed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.05a
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• pp.447-450
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• 2010

SAW Device 라는 Passive 소자는 ID Tag나 소형센서들을 대체할 수 있는 MEMS 기술의 초소형 Device 다. 이 SAW Device를 이용하면 독립된 공간이나 전원이 필요한 센서 제어 등을 대신할 수 있을 것이다. 이렇게 활용범위가 확대됨에 따라 다양한 SAW Device를 사용하기 위한 플랫폼이 요구된다. 하지만 현재 SAW Sensor는 많은 발전을 해왔지만 SAW Sensor를 활용할 수 있는 플랫폼의 발전은 미흡하기 때문에 본 논문에서는 이러한 SAW Device를 측정할 수 있는 SAW Reader를 FPGA를 이용하여 좀 더 간단하고 효율적인 Reader platform을 구현해 보고자 한다.