• Journal of Korea Multimedia Society
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• v.20 no.6
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• pp.853-864
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• 2017

HD padding area is essential redundancy in HD broadcasting. It is possible to use this padding area for the purpose of improving DTV broadcasting services. For utilization of this area, The bit of a service data was converted to black and white $8{\times}8$ block image. Converted block images are compressed with active video and are delivered to a receiver as only DC coefficients in a video stream. video quality is not effected by the proposed method, and service data was perfectly recovered in receiver without errors by using block average and threshold. The proposed utilization of HD essential padding area can possibly overcome the limited transmission stream rate with the bandwidth of HD broadcasting. If service data in transport or video stram were transferred using this padding area, it is possible to improve video quality with expanded video stream rate. Additionally, because the proposed methods are based on well-established standards, it is also useful for world-wide HD broadcasting systems such as ATSC, DVB, and IPTV.

• JSTS:Journal of Semiconductor Technology and Science
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• v.17 no.4
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• pp.499-504
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• 2017

A UHF CMOS variable gain low-noise amplifier (LNA) is designed for mobile digital TV tuners. The proposed LNA adopts a feedback topology to cover a wide frequency range from 474 to 868 MHz, and it supports the notch filter function for the interoperability with the GSM terminal. In order to handle harmonic distortion by strong interferers, the gain of the proposed LNA is step-controlled while keeping almost the same input impedance. The proposed LNA is implemented in a $0.11{\mu}m$ CMOS process and consumes 6 mA at a 1.5 V supply voltage. In the measurement, it shows the power gain of greater than 16 dB, NF of less than 1.7 dB, and IIP3 of greater than -1.7 dBm for the UHF band.

• Journal of Communications and Networks
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• v.15 no.5
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• pp.496-503
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• 2013

In an orthogonal frequency division multiplexing system, conventional interpolation techniques cannot correctly balance performance and overhead when estimating dynamic long-delay channels in single frequency networks (SFNs). In this study, classical filter analysis and design methods are employed to derive a complex interpolator for maximizing the resistible echo delay in a channel estimator on the basis of the correlation between frequency domain interpolating and time domain windowing. The coefficient computation of the complex interpolator requires a key parameter, i.e., channel length, which is obtained in the frequency domain with a tentative estimation scheme having low implementation complexity. The proposed complex adaptive interpolator is verified in a simulated digital video broadcasting for terrestrial/handheld receiver. The simulation results indicate that the designed channel estimator can not only handle SFN echoes with more than $200{\mu}s$ delay but also achieve a bit-error rate performance close to the optimum minimum mean square error method, which significantly outperforms conventional channel estimation methods, while preserving a low implementation cost in a short-delay channel.

• Journal of Life Science
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• v.15 no.1 s.68
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• pp.141-146
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• 2005

For a long time Rhus vemiciflua Stokes (RVS) has been traditionally used as a herbal plant in Asia. In this study, we have investigated the effect of acetone extract of Rhus verniciflua Stokes (RVSE) and fisetin, a component of RVSE, on DNA damage response in NIH3T3 cells. Exposure of cells to DVB light $(200 J/m^2)$ and postincubation in growth medium for 48 hr resulted in a decrease of cell viability to about $10-20\%$ of nontreated control. Addition of various concentrations of RVSE in the postincubation medium, however, significantly increased the cell viability as compared with the values expected. The genotoxicity-decreasing effect was also demonstrated in cells exposed to UVB light and incubated in medium containing fisetin. The genotoxicity-decreasing effect of RVSE and fisetin was further demonstrated by various analyses including cell morphology studies, trypan blue exclusion assay and DAPI staining. By Annexin V binding analysis, RVSE and fisetin were shown to decrease the early apoptosis induced by UVB exposure. These results suggest the RVSE contain components that either increase the DNA repair or decrease the apoptosis in UVB-exposed cells.

• Journal of the Korean Chemical Society
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• v.31 no.5
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• pp.457-463
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• 1987

The total synthesis of insulin A chain (1-21) with properly protected sulfhdryl groups of three cysteins for the correct intra and inter disulfide bond formation has been accomplished on 2-bromopropionylated 2% DVB-styreneresin support employing manually operated rotary vessel. The sulfhydryl groups of cysteins were protected with acetamidomethyl, benzyl, and benzhydryl respectively. Glutamine and asparagine were attached to the peptide chain by active ester coupling, all other amino acids were coupled with DCC/HOBT. The synthesized peptide was purified by DEAE Sephadex A-25 and gel filtration Sephadex LH-20. The final product was found to be homogeneous by HPLC, electrophoresis, and amino acid analysis. The overall yield of the pure isolated peptide was 6%.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.305-313
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• 1999

To demodulate the received OFDM signal, symbol timing detection which finds symbol start in the received sample stream is required in the system initialization. In this paper, we analyze the effect of symbol timing offset and propose a new symbol timing detection algorithm, which is using the guard interval. The proposed algorithm requires low computational process and small memory size, and dose not be affected by frequency offset and phase offset. In addition, We apply this algorithm to European digital TV broadcasting model based on OFDM to evaluate the performance in AWGN and multipath fading channel by the computer simulation.

• Journal of Environmental Health Sciences
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• v.32 no.5 s.92
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• pp.492-498
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• 2006

Ultraviolet(UV) radiation causes a variety of biological effects on the skin, including inflammation, pigmentation, photoaging and cancer. Free radicals are involved in inflammatory skin reactions induced by UVB radiation. In this study, we investigated the effects of antioxidants(Tea, Korean red ginseng, Ginkgo biloba extract) on UVB-induced skin damage. Tea, KRG and EGb 761 were topically treated to dorsal skin of ICR mouse. The mice were also treated soon after IMED ($1.4KJ/m^{2}$) of UVB irradiation. Skin pigmentation of irradiated mouse was observed by a chromameter after 2 weeks. Topical application of Tea, KRG and EGb 761 for 2 weeks decreased skin pigmentation compared to DVB control group(p<.05). Tea, KRG and EGb 761 also reduced UVB-induced infiltration of inflammatory cells. These results showed that Tea, KRG and EGb 761 as a topical application may have preventive effect against UVB-induced skin damage.

• Membrane and Water Treatment
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• v.8 no.6
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• pp.575-590
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• 2017

PolyHIPEs membrane prepared with styrene (St), divinylbenzene (DVB), and ethylhexyl acrylate (EHA) can yield a unique pore structure provided by large voids highly interconnected by many small window throats. With the advantageous pore structure, PolyHIPE presents a potential as a support for carrier facilitated transport membrane. Tricaprylmethylammonium chloride (Aliquat 336) can be efficiently incorporated into the PolyHIPE membrane by a two-step solvent-nonsolvent method to obtain an Aliquat 336-immobilized PolyHIPE membrane with good stability. The study of Cr (VI) transport through Aliquat 336-immobilized PolyHIPE membrane indicates that the membrane has high initial flux and maxima stripping flux ($J_f^o=15.01({\mu}mol/m^2s)$, $J_s^{max}=6.15({\mu}mol/m^2s)$). The reusability study shows that the Aliquat 336-immobilized PolyHIPE membrane can maintain high Cr(VI) recovery efficiency even after 15 cycles of operations. The developed membrane was also used in the separation of Cr (VI) from other anions (i.e., $SO_4{^{2-}}$ and $NO_3{^-}$) and other cations (i.e., Ni (II), Mg (II) and Cu (II)) with good selectivity.

• Journal of Satellite, Information and Communications
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• v.3 no.2
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• pp.48-53
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• 2008

In the future, satellite communication systems, such as ISDB in Japan and DVB in Europe, are required to support higher transmission date rate for providing multimedia services including HDTV, high rate data communication etc. Considering the effectiveness of OFDM technique in efficient usage of frequency bandwidth and its robustness to the multi-path fading, several OFDM based standards have been proposed for satellite communication. However, the problem of high Peak to Average Power Ratio is one of the main obstacles for the implementation of OFDM based system. Many PAPR reduction schemes have been proposed for OFDM systems. Among these, the partial transmit sequences (PTS) is attractive as they obtain better PAPR property by modifying OFDM signals without distortion. In this paper, considering the complexity issue, we present a simplified minimum maximum (minimax) criterion and Sub-Optimal PTS algorithm to optimize the phase factor. This algorithm can be dynamically made tradeoff`f between performance and complexity on demand. In addition, we integrate guided scrambling (GS) with this method. Simulation in multiple antenna based OFDM system proves that the proposed Hybrid schemes can get much more PAPR reduction and do not require transmission of side information (SI). Thus it is helpful when implementing OFDM technique in satellite communication system.

• Journal of environmental and Sanitary engineering
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• v.17 no.1
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• pp.63-68
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• 2002

Amount of styrene and divinylbenzene(DVB) was adjusted under injection of nitrogen, copolymer having crosslink of 1%, 2% and 5% was synthesized and zinc chloride was added to it. Put into benzene, swell it, add potassium iodide and 1-aza-15-crown-5 of 21.93g in toluene solution and functional resin which can adsorb heavy metal ions by stir reflex at $55^{\circ}C$ for 30 hours was synthesized. The content of divinylbenzene of this resin was increased as crosslink increase, macroporous gets smaller and the content of chlorine was reduced, which affects macrocyclic ligand in the process of substitution and content of nitrogen was also reduced. And the form of functional synthetic resin was distorted by substitution reaction of hydrogen and chlorine atoms.