• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1120-1125
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• 2001

A new concept of piezoelectric smart panels for noise reduction in wide band frequencies is proposed and their possibility is experimentally investigated. Multi-mode damping is studied by using a newly proposed tuning method. The proposed panels are based on passive shunt damping methods. This method is based on electrical impedance model and maximizing the dissipated energy at the shunt circuit. four PZT are attached on smart panel for improving performance of transmission noise reduction. 0 prove the concept of piezoelectric smart panels, an acoustic measurement experiment was performed. The smart panels exhibit a good noise reduction in middle and high frequency ranges due to the mass effects of absorbing materials or/and the air gap. The use of piezoelectric smart panel renders noise reduction at resonance frequency. Noise reduction at multiple resonance frequencies is experimentally investigaed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.20 no.1
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• pp.110-115
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• 2021

A multi-band, compact, and complex vehicle roof antenna has become important in terms of car exterior design and multi-functions which include Radio, DAB/DMB, SXM, GNSS, Telematics, and V2X. In this paper, we propose a compact multi-band V2X pole-type roof antenna. Using impedance change characteristic, a single pole antenna which has multiband such as radio, DAB/DMB, telematics, and V2X band is proposed. With two patch antennas for GNSS and SXM, the dimension of a multiband roof antenna is 131x63x37mm only.

• Journal of Advanced Navigation Technology
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• v.18 no.6
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• pp.619-624
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• 2014

Nowadays there are various smart devices and development with the development of smart phones and that can be attached to the human body wearable computing device has been in the spotlight. In this paper, we proceeded developing wearable devices in watch type which can detect user's movement and developing a system which connects the wearable devices to smart TVs, or smart phones so that users can save and manage their physical information in those devices. Health care wearable devices already existing save information by connecting their systems to smart phones. And, smart TV health applications usually include motion detecting systems using cameras. However, there is a limit when connecting smart phone systems to different devices from various companies. Also, in case of smart TV, because some devices may not have cameras, there can be a limit for users who wants to connect their devices to smart TVs. Wearable device and user information collected by using the smart phone and when it is possible to exercise and manage anywhere. This information can also be confirmed by the smart TV applications. By using this system will be able to take advantage of the study of the behavior of the future work of the user more accurately be measured in recognition technology and other devices.

• ETRI Journal
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• v.40 no.2
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• pp.167-179
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• 2018

This paper proposes an IEEE 802.15.4m compliant TV white-space orthogonal frequency-division multiplexing (TVWS)-(OFDM) radio frequency (RF) transceiver that can be adopted in advanced metering infrastructures, universal remote controllers, smart factories, consumer electronics, and other areas. The proposed TVWS-OFDM RF transceiver consists of a receiver, a transmitter, a 25% duty-cycle local oscillator generator, and a delta-sigma fractional-N phase-locked loop. In the TV band from 470 MHz to 698 MHz, the highly linear RF transmitter protects the occupied TV signals, and the high-Q filtering RF receiver is tolerable to in-band interferers as strong as -20 dBm at a 3-MHz offset. The proposed TVWS-OFDM RF transceiver is fabricated using a $0.13-{\mu}m$ CMOS process, and consumes 47 mA in the Tx mode and 35 mA in the Rx mode. The fabricated chip shows a Tx average power of 0 dBm with an error-vector-magnitude of < 3%, and a sensitivity level of -103 dBm with a packet-error-rate of < 3%. Using the implemented TVWS-OFDM modules, a public demonstration of electricity metering was successfully carried out.

• Journal of Integrative Natural Science
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• v.5 no.4
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• pp.253-256
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• 2012

The rugate porous silicons containing multiple photonic band gaps have been generated by applying a composite waveform summed three computer-generated pseudo-sinusoidal current waveforms and exhibit three sharp photonic band gaps in the optical reflectivity spectrum. Generated multiple rugate porous silicons display three rugate peaks corresponding to the each of the sine components varied from 0.42, 0.36, and 0.30 Hz, with a spacing of 0.06 Hz between each sine component. The resulting rugate PSi films have been removed from the silicon substrate by applying an lift-off current and are then made into particles by ultrasono-method in a organic solution. The sensing experiments using these particles for organic solvents such as toluene, hexane, acetone, and methanol have been achieved. Condensing of organic vapors in the pores increases the refractive indices of entire particle which results a red shift in the photonic peaks.

• Proceedings of the Korean Society of Computer Information Conference
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• 2017.07a
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• pp.199-200
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• 2017

본 논문에서는 최근 황사 및 미세 먼지 등으로 늘어나는 환경적 오염으로부터 어린이들이 올바른 마스크 사용을 할 수 있도록 스마트 기능이 포함된 마스크를 제안하는 것이다. 제 4차 산업혁명으로 인하여 사물인터넷이나 스마트 제품은 날로 급증하고 있는 추세이다. 따라서, 어린이들이 많이 사용하는 마스크 제품에 스마트한 기능을 넣고자 한다. 스마트 밴드를 통해 미세먼제 오염도를 측정할 수 있고, 호흡 상태를 파악하고 분비물의 상태를 분석할 수가 있다. 따라서 의료기관을 방문하기 전까지 어린이들의 건강상태를 보다 즉각적으로 파악할 수가 있다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.441-442
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• 2022

현재 고령화 시대에 접어들며 대한민국 고령화 노인 비율이 2022년 기준 17%에 도달했다. 그만큼 대한민국의 고령화 시대가 급격하게 진행되고 있다. 노약자 수가 증가함에 따라 안전사고 발생 빈도가 증가했다. 본 논문은 노약자들이 심박, 체온 센서의 측정값을 그래프로 표현한 후 검사결과를 토대로 의사와 원격진료가 가능하여 병원을 방문하지 않고 의사와 상담 및 진료가 가능하다. 또한, 낙상 상황 발생 시에는 낙상 상황 발생 후 일정 시간 동안 움직임이 감지되지 않으면 보호자에게 위치 및 안전문자가 전송되어 안전사고 문제를 예방할 수 있다.

• ETRI Journal
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• v.42 no.4
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• pp.585-595
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• 2020

Integration of multiple communication technologies in a smart grid (SG) enables employing cognitive radio (CR) technology for improving reliability and security with low latency by adaptively and effectively allocating spectral resources. The versatile features of the CR enable the smart meter to select either the unlicensed or the licensed band for transmitting data to the utility company, thus reducing communication outage. Demand response management is regarded as the control unit of the SG that balances the load by regulating the real-time price that benefits both the utility company and consumers. In this study, joint allocation of the transmission power to the smart meter and consumer's demand is formulated as a two stage multi-armed bandit game in which the players select their optimal strategies noncooperatively without having any prior information about the media. Furthermore, based on historical rewards of the player, a real-time pricing adaptation method is proposed. The latter is validated through numerical results.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2003.04a
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• pp.382-387
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• 2003

Many type of smart materials and control laws are available to actively adjust the structure from various external disturbances. Usually, a certain type of control law to activate a specific smart material is tell established, but the effectiveness of the control scheme is limited by the choice of the smart materials and the responses of the structure. ER fluid is adequate to provide small but arbitrary control forces at any point along the structure. It was found that active vibration control of the structure embedded with ER fluids fluidly to suppress the vibration excited with broad band frequency due to the limited change of the structure characteristics. To compensate this limited effect of the control scheme with ER fluid alone, PPF control using PZT as an actuator is added to construct a hybrid controller.

• Journal of Integrative Natural Science
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• v.3 no.2
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• pp.84-88
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• 2010

Photonic crystals containing rugate structures from a single crystalline silicon wafer was obtained by using a sinoidal alternating current during an electrochemical etch procedure. Photonic crystals were isolated from the silicon substrate by applying an electropolishing current and were then made into particles by using an ultrasonic fracture in an ethanol solution to give a smart dust. Smart dusts exhibited their unique nanostructures and optical characteristics. They exhibited sharp photonic band gaps in the optical reflectivity spectrum. The size of smart dust obtained was in the range of 10-20 nm.