• Journal of Mechanical Science and Technology
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• v.20 no.4
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• pp.554-560
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• 2006

This paper describes the demonstration of successful fabrication and initial characterization of micromachined pressure sensors and micromachined jets (microjets) fabricated for use in macro flow control and other applications. In this work, the microfabrication technology was investigated to create a micromachined fluidic control system with a goal of application in practical fluids problems, such as UAV (Unmanned Aerial Vehicle)-scale aerodynamic control. Approaches of this work include: (1) the development of suitable micromachined synthetic jets (microjets) as actuators, which obviate the need to physically extend micromachined structures into an external flow; and (2) a non-silicon alternative micromachining fabrication technology based on metallic substrates and lamination (in addition to traditional MEMS technologies) which will allow the realization of larger scale, more robust structures and larger array active areas for fluidic systems. As an initial study, an array of MEMS pressure sensors and an array of MEMS modulators for orifice-based control of microjets have been fabricated, and characterized. Both pressure sensors and modulators have been built using stainless steel as a substrate and a combination of lamination and traditional micromachining processes as fabrication technologies.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.12
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• pp.1104-1111
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• 2011

This paper investigates the filtered velocity feedback(FVF) controller for the reduction of the acoustic power radiated from a clamped beam. The instability problem due to the non-collocated sensor/actuator configuration when using PZT actuator should be sorted out. The roll-off property of the FVF controller at high frequency helps to alleviate the instability. The dynamics of clamped beams under forces and moments pair and the FVF controller are first formulated. The formulation of the sound radiated power is followed. The open loop transfer function(OLTF) synthesized with 100 modes is used to determine the stability of the control system. The control performance is finally estimated. The levels of the vibration and the sound radiated power are reduced in the wide bandbelow the tuning mode of the FVF controller.

• ETRI Journal
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• v.27 no.3
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• pp.243-249
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• 2005

A mobile antenna for multimedia communications with Ku-band geostationary satellite KOREASAT-3 and JSAT-2A is presented. The forward link of the satellite communication is 11.7 to 12.75 GHz, and the return link is 14.0 to 14.5 GHz. The mobile antenna is designed to be a stair structure using 24 active phased array elements in order to provide a low profile, and to be at a non-periodic array distance using the genetic algorithm. Also, the designed antenna uses the double beam forming method for stable satellite tracking. The fabricated mobile antenna is examined using various experiments to confirm its capability for practical application. From the measured results, the fabricated mobile antenna system is confirmed to have a good performance.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.2260-2265
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• 2005

In this paper, an active vibration control of a tensioned elastic axially moving string is investigated. The dynamics of the translating string are described by a non-linear partial differential equation coupled with an ordinary differential equation. A time varying control in the form of right boundary transverse motions is proposed in stabilizing the transverse vibrations of the translating continuum. A control law based on Lyapunov's second method is derived. Exponential stability of the closed-loop system is verified. The effectiveness of the proposed controller is shown through simulations.

• Tuberculosis and Respiratory Diseases
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• v.38 no.3
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• pp.228-235
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• 1991

Pulmonary surfactant is a lipoprotein complex composed primarily of phospholipid and lungspecific apoproteins that reduces surface tension in the alveolus and maintains alveolar stability at low lung volume. Three families of lung-specific apoproteins have been described: SP-A, a glycoprotein with a reduced molecular weight of 28~36 KDa. SP-B a hydrophobic protein with a nonreduced molecular weight of 18 KDa, and SP-C a hydrophobic protein with a non-reduced molecular weight of 5~8 KDa. Surfactant proteins have important roles in regulating surfactant metabolism as well as in determining its physical properties. The synthesis of the active surfactant peptides appears to be modulated by system with considerable complexity, including numerous levels of regulation such as cell-specific, hormonal and developmental controls. Endotoxin appears to alter surfactant protein mRNAs differentially. It is hoped that the elucidation of the factors controlling the synthesis and metabolism of the surfactant proteins will aid in understanding the pathogenesis of hyaline membrane disease and offer new avenues for the therapy and diagnosis of ther pulmonary disorders as well.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.5
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• pp.261-268
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• 2018

Phase Change Memory(PCM) with low power consumption and high integration attracts attention as a next generation nonvolatile memory replacing DRAM. However, there is a problem that PCM has long latency and high energy consumption due to the writing operation. The PCM & DRAM hybrid memory structure is a fruitful structure that can overcome the disadvantages of such PCM. However, the page replacement algorithm is important, because these structures use two memory of different characteristics. The purpose of this document is to effectively manage pages that can be referenced in memory, taking into account the characteristics of DRAM and PCM. In order to manage these pages, this paper proposes an page replacement algorithm based on frequently accessed and recently paged. According to our simulation, the proposed algorithm for the DRAM&PCM hybrid can reduce the energy-delay product by around 10%, compared with Clock-DWF and CLOCK-HM.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.5B no.4
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• pp.374-381
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• 2005

The ability to provide quality power has become a significant issue in power systems. The main causes of poor power quality are harmonic currents, poor power factor, supply-voltage variations, etc. A technique of achieving both active current distortion compensation, power factor correction and also mitigating the supply-voltage variation (sag or swell) at the load side is presented in this paper. The operation and rating issues of the proposed Single-phase Unified Power Quality Conditioner are also highlighted. To reduce the total cost while simultaneously increasing the performance, the system is fully digitally controlled using the fixed-point TMS320F240 digital signal processor. The performances of the UPQC, which is composed by shunt and series PWM controlled-converters, have been verified on a laboratory prototype.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.377-383
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• 2011

This paper reports the filtered velocity feedback (FVF) controller to reduce the acoustic power from clamped beams. The instability problem due to the non-collocated sensor/actuator configuration when using PZT actuator should be resolved. The roll-off property of the FVF controller at high frequency helps to alleviate the instability. The dynamics of clamped beams under forces and moments pair and the FVF controller are first formulated. The formulation of the sound radiated power is followed. The open loop transfer function (OLTF) synthesized with 100 modes is used to determine the stability of the control system. The control performance is finally estimated. The levels of the vibration and the sound radiated power are reduced in the wide band below the tuning mode of the FVF controller.

• Korean Journal of Organic Agriculture
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• v.21 no.3
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• pp.351-362
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• 2013

The Purpose of this paper is to suggest sustainable strategies of the project for developing large-scale environment-friendly agricultural districts (LSEAD). This study used assessment 3 indicators, efficiency, impact and sustainability of environment-friendly agricultural certification area and farmers, management situations of crop-livestock circulation center, educations for environment-friendly farming, changes of farmer's income and so on. This project has contributed to develop environment- friendly agriculture and model of LSEAD. And for sustainable development of LSEAD, it is necessary to renovate crop-livestock circulation centers, promote organic farming of resource-circulation type, converse to non-pesticide or organic farming of low pesticide one, do active marketing activities, establish a governance system of business projects and so forth.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.53-55
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• 2005

The surface potential variations are measured, according to the enhanced measuring speed and voltage sensitivity, using an active device, such as a field effect transistor $(FET)^{1-3}$. In this study, the surface potential was mapped in the patterned $SiO_2$ medium at room temperature. An improved FET-tip cantilever, which has a source, a drain, and an n- channel, was used in this study. The potential images were analyzed both in the contact mode and the non-contact mode, using only a pre-amplifier system instead of a lock-in the amplifier.