• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.27 no.1
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• pp.94-99
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• 2017

Breaking the rigid connection between the two faces of the wall can significantly improve the sound transmission loss of the wall. This is usually achieved by resiliently mounting the gypsum board on one of the two faces of the wall using resilient channel. Resilient channel with less stiffness than that of air cavity could move the resonance frequency of the light-weight wall. So we can get higher sound transmission loss at low frequencies for light-weight wall using resilient channel. It's sound transmission loss is 17 dB higher than that of single stud wall, and 5 dB higher than that of double stud wall.

• ETRI Journal
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• v.29 no.4
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• pp.524-526
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• 2007

In this letter, we study the multicast protection problem in sparse-splitting wavelength-division multiplexing (WDM) optical network, and propose a novel multicast protection algorithm called the shared source-leaf path-based protection (SLPP) algorithm. Unlike the proposals in previous studies, the backup paths derived by SLPP can share wavelength with the primary tree in sparse-splitting WDM networks. Simulations are used to evaluate the effectiveness of the SLPP algorithm.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.710-714
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• 2002

Whenever a noise problem of a product is concerned, a first step is to identify the energy transmission path whether it is an air-borne or a structure-borne. Depending on the characteristic of the noise path, tools on the noise reduction are different. In this paper. an important aspect of the “mass law” in a noise transmission has been investigated. Since an air-borne has 20 dB/Decade, and a structure-borne 10 dB/Decade of a sound transmission loss due to a mass, an engineer who aims to have a light product design should have an enough knowledge on the mass law, especially, the sensitivity of the weight itself. A honeycomb plate is examined as a sample of a light structure to implement a mass law.

• Proceedings of the KIPE Conference
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• 2005.07a
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• pp.143-145
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• 2005

This paper describes the transmission method of an information using communication networks between RTU(Remote Terminal Unit) and PCU(Protection and Control System) of the DC switchgear for Light Railway Vehicle. Also the test result carried out in the laboratory was represented. In this test, transmission signal waveform, polling time, response time and request/response frame between RTU and PCU were measured. The field test including the measurements of analog signal and status of the digital logic operation of PCU was conducted in Gyeongsan Test Track.

• Journal of the Korean Institute of Telematics and Electronics
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• v.24 no.5
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• pp.868-873
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• 1987

Holographic diffraction gratings which are the core element of the optical instruments such as a spectrophotometer have been fabricated using the photoresist as a recording material. A 488nm line from an argon laser is used in making the gratings. Transmission type surface-relief phase grating and reflection type which is fabsricated by coating the aluminum on the transmission type with thickness 2000\ulcornerare fabricated, the spatical frequency of which are 1200 lines/mm. Diffraction efficiency, scattered light and wave-front aberratin are measured to test the performance of the developed gratings. A marimum diffraction efficiency is given when light is incident at the Bragg angle. Theoretical efficiency is about 80%, but measured efficiency of the transmission type and reflection type is 50% and 45%, respectively.

• Journal of IKEEE
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• v.13 no.4
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• pp.70-74
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• 2009

In this paper, We propose the visible light communication(VLC) link based on white light emitting diode (LED) and Photo detector(PD). The proposed architecture is demonstrated experimentally and its performance is verified through the experimental results of quality-factor(Q-factor) and eye pattern of 10Mb/s PRBS signal. The ambient light effect from a typical type fluorescent lamp source was also analyzed. when the distance between the LED and the PD is about 1m, error free wireless transmission of the LED was achieved up to 10Mb/s data rate. Under the condition with ambient light, low BER, data transmission of the VLC link is achieved up to 5Mb/s data rate at 1m. Also, when the PD is placed away from the center, low BER data transmission of the VLC link is achieved up to 1Mb/s at 10cm and 10Mb/s at 5cm.

• Journal of the Optical Society of Korea
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• v.19 no.4
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• pp.371-375
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• 2015

The impact of equivalent optical bandwidth on the performance of a system using a reflective electroabsorption modulator (R-EAM) based optical source has been experimentally evaluated with signals operating at 2.5 Gb/s and beyond. The equivalent optical bandwidth of our source with a broadband seed light was simply adjusted by using a bandwidth tunable optical filter. From the measurements, we have estimated the required equivalent optical bandwidth of our source for an error-free transmission (@ bit-error-rate of $10^{-12}$) and a forward error correction (FEC) threshold of $2{\times}10^{-4}$.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.07a
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• pp.300-303
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• 2003

The design rule for 8.5kV LTT was discussed here. An inherent integrated breakover diode (BOD) for self -protection function and multi-amplified gate (AG) for improved di/dt capability of LTT was introduced in principle. The trade-off between light triggering input source and high dV/dt limitation has been treated via narrow grooved P-base for gate design. Key process technology for LTT was given, too.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.33-33
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• 2000

In this paper a new distributive control system for BA(Building Automation ) lighting control used on general microprocessors is presented. For optimal lighting control and saving energy, The system have to control the group and pattern lighting control as well as individual light control at one time. Tn this paper, This functions are accomplished with low-cost and simple microprocessor. A plurality of modulated light control terminals are connected to the central control unit through a pair of power line. This power line provide both power and signal to the each terminal and the data is transmitted through cyclic time division multiplex transmission. With this structure a low-cost distributive control system for lighting applications has been achieved, allowing energy and maintenance saving and reliability increase of the light control system.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.383-384
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• 2008

$SnO_2$ oxides are considerable interest for the development of transparent electrode, thin film resistor and gas sensors. Electrospinning is a class of nanofiber forming processes by which electrostatic forces are employed to control the production of nanofibers. In this study, antimony doped tin oxide thin films were prepared by electrospinning process. Effects of ATO doping concentration and applied voltage on electrical and light transmission properties were investigated.