• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.288-291
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• 2003

The technology and performance of the world-largest 54-inch LCD TV using PVA mode have been introduced from two points of view: one is to manufacture large-size panels, the other is to improve electro-optical performance required for multimedia applications. Current ongoing research activities that have been explored include new stitching design, one drop filling with column spacer, response time less than one frame rate, color performance and light efficiency enhancement.

• Steel and Composite Structures
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• v.23 no.5
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• pp.585-596
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• 2017

Tubular joints have been widely used in offshore platforms and space structures due to their merits such as easy fabrication, aesthetic appearance and better static strength. For existing tubular joints, a grouted sleeve reinforced method was proposed in this paper. Experimental tests on five tubular T-joints reinforced with the grouted sleeve and two conventional tubular T-joints were conducted to investigate their mechanical behaviour. A constant axial compressive force was applied to the chord end to simulate the compressive state of the chord member during the tests. Then an axial compressive force was applied to the top end of the brace member until the collapse of the joint specimens occurred. The parameters investigated herein were the grout thickness, the sleeve length coefficient and the sleeve construction method. The failure mode, ultimate load, initial stiffness and deformability of these joint specimens were discussed. It was found that: (1) The grouted sleeve could change the failure mode of tubular T-joints. (2) The grouted sleeve was observed to provide strength enhancement up to 154.3%~172.7% for the corresponding un-reinforced joint. (3) The initial stiffness and deformability were also greatly improved by the grouted sleeve. (4) The sleeve length coefficient was a key parameter for the improved effect of the grouted sleeve reinforced method.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.8 s.350
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• pp.97-102
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• 2006

This paper presents a novel technique of efficiency enhancement for dual mode transmitter. The future dual mode transmitter incorporates an amplifier which generates different level of output for different applications. For WiBro, the output is 1W at 2.3GHz, and for wireless LAN, the output is less than 100mW at 2.4GHz. Simple bias switching is proposed to get the higher efficiency at both of the applications. Without the bias switching the amplifier shows 10% PAE at 20dBm output for wireless LAN, but using a preselected lower bias, the efficiency improves up to 35%. This technique becomes more useful as the need of many function convergence terminals is increasing.

• Journal of the Korean Institute of Telematics and Electronics
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• v.21 no.6
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• pp.1-6
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• 1984

This paper describes that the compensation of frequency dependent attenuation (F.D.A.) and faithful envelope detection using the analytic signal magnitude (A.S.M.) improve the range resolut ion in an acoustic medium. It is shown that a mean of computing the magnitude of. analytic signal is better than that of conventional A-mode. In addition, this proposed method is much easier than the above methods to detect two closely spaced interfaces on the A-mode. As the result of experiment, we obtained range resolution of 0.5 mm with transducer of 3.5 MHz. This method can be applied to medical experiment, diagonostic and nondestructive testing.

• Journal of Sensor Science and Technology
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• v.25 no.2
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• pp.143-147
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• 2016

Characteristics of the conventional gold (Au) surface plasmon resonance (SPR) chip, bi-metallic(Au/silver (Ag)) SPR chip, and tri-metallic(Au/Ag/Au) SPR chip were investigated and compared in the intensity measurement mode for the enhancement of SPR image sensor reactivity. Reflectance curves of the Au, bi- and tri-metallic SPR chips were acquired in phosphate-buffered saline (PBS) solution and were compared. The line width of the reflectance curve of the bi-metallic chip was the narrowest among the three different types of the chips. Also, the tangential slope of the bi-metallic chip was steeper than those of the other chips. Various concentrations of bovine serum albumin (BSA) were utilized in the SPR experiment. As a result, among the above three chips reflectance variation value of the bi-metallic chip was the largest.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.7
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• pp.667-675
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• 2012

A damage estimation method for support structure of offshore wind turbine using modal parameters is presented for effective structural health monitoring. Natural frequencies and mode shapes for a support structure with monopile of an offshore wind turbine were calculated considering soil condition and added mass. A neural network was learned based on training patterns generated by the changes of natural frequency and mode shape due to various damages. Natural frequencies and mode shapes for 10 prospective damage cases were input to the trained neural network for damage estimation. The identified damage locations and severities agreed reasonably well with the accurate damages. Multi-damage cases could also be successfully estimated. Enhancement of estimation result using another parameters as input to neural network will be carried out by further study. Proposed method could be applied to other type of support structure of offshore wind turbine for structural health monitoring.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.111-117
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• 2008

In this paper, we propose an approach to improve the performance of voiced/unvoiced (V/UV) decision under background noise environments for the selectable mode vocoder (SMV) of 3GPP2. We first present an effective analysis of the features and the classification method adopted in the SMV. And then feature vectors which are applied to the GMM are selected from relevant parameters of the SMV for the efficient voiced/unvoiced classification. For the purpose of evaluating the performance of the proposed algorithm, different experiments were carried out under various noise environments and yields better results compared with the conventional scheme of the SMV.

• Structural Engineering and Mechanics
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• v.44 no.6
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• pp.705-733
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• 2012

In this work, an experimental examination was carried out to study interfacial stresses developed at the junction zones between carbon fiber reinforced plastic (CFRP) fabrics (~1 mm thickness) and tensile concrete portion in CFRP retrofitted RC beams. In this respect, initially six similar RC beams of $150{\times}150{\times}1000mm$ dimensions were prepared. Three of which were strengthened with CFRP fabrics at the tensile side of the beams. Furthermore, a notch was cut at the center of the bottom surface for all of the studied beams. The notch was 15 mm deep and ran across the full width of tension side of the beams. The mentioned interfacial stresses could be calculated from strains measured using strain gauges mounted on the interface zone of the tensile concrete and the CFRP sheet. Based on the results obtained, it is shown that interfacial stresses developed between CFRP fabrics and RC beam had a noticeable effect on debonding failure mode of the latter. The load carrying capacity of CFRP strengthened RC specimens increased ~75% compared to that of the control RC beams. This was attributed to the enhancement of flexural mode of the former. Finally, finite element analysis was also utilized to verify the measured experimental results.

• Journal of IKEEE
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• v.15 no.4
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• pp.313-318
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• 2011

The effects of external continuous wave optical injection on spectral comb of a 10 GHz harmonically mode-locked semiconductor fiber ring laser have been studied. Greater than 40 dB spectral deeps in the spectral comb and greater than 30 dB reduction of supermode beating noise are achieved by injecting coherent light with ~ 100 KHz spectral width. To examine the possibility of using a low-cost seed source, we replace the seed source by a DFB laser with ~ 10 MHz spectral width. It shows similar spectral deeps, however supermode beating noise enhancement, rather than reduction, is observed.

• Journal of Sensor Science and Technology
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• v.24 no.6
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• pp.423-428
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• 2015

A bimetallic chip made of gold and silver was investigated in intensity interrogation mode to confirm enhancement of the SPR sensor resolution. Both reflectance curves of the bimetallic chip and the conventional gold chip was acquired and compared. The line width of the reflectance curve of the bimetallic chip was narrower than that of the conventional Au chip, resulting in steeper tangential slope. The reflectance was monitored at the angle related to the steepest tangential slope. The change in reflectance of the bimetallic chip was larger than that of the Au chip. The critical angle was analyzed by differentiating the reflectance with respect to incident angle twice. Acquiring the critical angle regarding to the sample informs the refractive index of the sample. Using various concentration of Bovine Serum Albumin, we confirmed that refractive index was linearly related to variation of reflectance of the bimetallic chip.