• IEMEK Journal of Embedded Systems and Applications
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• 제6권5호
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• pp.281-286
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• 2011

FMCW Radar sensor is commonly used for an automobile collision avoidance system for rider's safe. Systems using FMCW radar, however, would be one of expensive solutions for just simple rear obstacle detection purpose due to its high cost. In this letter, a short range rear obstacle detector using novel 24GHz AM radar sensor is presented. It can be implemented at significantly lower cost than FMCW radar for practical commercialization. The proposed AM radar sensor module is fabricated in a single aluminum housing to reduce the overall size while using single power supply voltage of 12V with 1200mA current for automotive applications. The measured detection range is up to 210cm with 10cm of distance resolution, which is suitable for a parking assistance system for automobiles.

• Physical Therapy Korea
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• 제20권3호
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• pp.89-99
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• 2013

The purposes of this study were: 1) to show the item difficulty hierarchy of walking/moving construct of the International Classification of Functioning, Disability and Health-Activity Measure (ICF-AM), 2) to evaluate the item-level psychometrics for model fit, 3) to describe the relevant physical activity defined by level of activity intensity expressed as Metabolic Equivalent of Tasks (MET), and 4) to explore what extent the empirical activity hierarchy of the ICF-AM is linked to the conceptual model based on the level of energy expenditure described as MET. One hundred and eight participants with lower extremity impairments were examined for the present study. A newly created activity measure, the ICF-AM using an item response theory (IRT) model and computer adaptive testing (CAT) method, has a construct on walking/moving construct. Based on the ICF category of walking and moving, the instrument comprised items corresponding to: walking short distances, walking long distances, walking on different surfaces, walking around objects, climbing, and running. The item difficulty hierarchy was created using Winstep software for 20 items. The Rasch analyses (1-parameter IRT model) were performed on participants with lower extremity injuries who completed the paper and pencil version of walking/moving construct of the ICF-AM. The classification of physical activity can also be performed by the use of METs that is often preferred to determine the level of physical activity. The empirical item hierarchy of walking, climbing, running activities of the ICF-AM instrument was similar to the conceptual activity hierarchy based on the METs. The empirically derived item difficulty hierarchy of the ICF-AM may be useful in developing MET-based activity measure questionnaires. In addition to convenience of applying items to questionnaires, implications of the finding could lead to the use of CAT method without sacrificing the objectivity of physiologic measures.

• Mycobiology
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• 제33권1호
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• pp.41-50
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• 2005

Results from an innovative approach to improve remediation in the rhizosphere by encouraging healthy plant growth and thus enhancing microbial activity are reported. The effect of arbuscular mycorrhizal fungi (Am) on remediation efficacy of wheat, mungbean and eggplant grown in soil spiked with polyaromatic hydrocarbons (PAH) was assessed in a pot experiment. The results of this study showed that Am inoculation enhanced dissipation amount of PAHs in planted soil, plant uptake PAHs, dissipation amount of PAHs in planted versus unplanted spiked soil and loss of PAHs by the plant-promoted biodegradation. A number of parameters were monitored including plant shoot and root dry weight, plant tissue water content, plant chlorophyll, root lipid content, oxido-reductase enzyme activities in plant and soil rhizosphere and total microbial count in the rhizospheric soil. The observed physiological data indicate that plant growth and tolerance increased with Am, but reduced by PAH. This was reflected by levels of mycorrhizal root colonization which were higher for mungbean, moderate for wheat and low for eggplant. Levels of Am colonization increased on mungbean > wheat > eggplant. This is consistent with the efficacy of plant in dissipation of PAHs in spiked soil. Highly significant positive correlations were shown between of arbuscular formation in root segments (A)) and plant water content, root lipids, peroxidase, catalase polyphenol oxidase and total microbial count in soil rhizosphere as well as PAH dissipation in spiked soil. As consequence of the treatment with Am, the plants provide a greater sink for the contaminants since they are better able to survive and grow.

• Journal of Korea Foundry Society
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• 제18권4호
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• pp.364-372
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• 1998

Effects of Si and Ca additions on the mechanical properties of AM60 based Mg alloys have been investigated. Hardness of the AM60 based Mg alloys reached a maximum value after aging for approximately 33 hours but the amount of hardness increase was negligible. The poor age hardening response of the alloys was due to low Al content, which implies that Al content must be >6 wt.% to observe age hardening effect. The tensile and yield strength increased with increasing Al, Si, and Ca content but elongation decreased with increasing Al and Si content. The best mechanical properties obtained in AM 40-2.5Si-0.2Ca alloy after T4 heat treatment were as follows; tensile strength 193.4 MPa, yield strength 79.2 MPa, and elongation 11.2%. High temperature property obtained from creep test was also improved by introducing $Mg_2Si$ which has high hardness, high melting temperature and low thermal expansion coefficient.

• Korean Journal of Microbiology
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• 제29권6호
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• pp.387-391
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• 1991

Methylobacterium extorquens AM1 growing on methanol as a sole source of carbon and energy was found to grow most rapidly (t$t_{d}$ =6h) at 30.deg.C in a mineral medium (pH 7.0) containing 0.5% (v/v) methanol which was agitated at 200 rpm (optimal cultivation condition). Cells grown under the optimal cultivation condition contained more spermidine, but less putrescine, than the cells grown on 2.5%(v/v) ( $t_{d}$ =8h ) or at 20.deg.C ( $t_{d}$ =8h ). Cells cultivated under the optimal condition was found to contain more spermidine than the cells grown at pH 6.0 (( $t_{d}$ =7h ) and pH 8.0 ($t_{d}$ =7.3h). the cells growing at the stationary phase under the optimal condition accumulated more spermine or putrescine than the cells growing at the same phase on 2.5%(v/v) methanol or at pH 6.0 and pH 8.0, respectively. M. extorquens AM1 grown in a medium agitated at 100 rpm ( $t_{d}$ =8.8h ) contained less spermidine and spermine than the cells grown under the optimal cultivation condition.

• Journal of Pharmaceutical Investigation
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• 제36권5호
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• pp.309-314
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• 2006

The multicellular layers(MCL) of human cancer cells is a three dimensional(3D) in vitro model for human solid tumors which has been used primarily for the assessment of avascular penetration of anti-cancer drugs. For anti-cancer drugs with penetration problem, MCL represents a good experimental model that can provide clinically relevant data. Calcein-AM is a fluorescent dye that demonstrates the cellular vitality in a graded manner in cancer cell culture system. In the present study, we evaluated the use of calcein-AM for determination of anti-proliferative activity of anti-cancer agents in MCL model of DLD-1 human colorectal cancer cells. Optical sectioning of confocal imaging was compromised with photonic attenuation and penetration barrier in the deep layers of MCL. By contrast, fluorescent measurement on the cryo-sections provided a feasible alternative. Cold pre-incubation did not enhance the calcein-AM distribution to a significant degree in MCL of DLD-1 cells. However, the simultaneous determination of drug penetration and cellular vitality appeared to be possible in drug treated MCL. In conclusion, these data suggest that calcein-AM can be used for the simultaneous determination of drug-induced anti-proliferative effect and drug penetration in MCL model.

• The Journal of Korean Institute of Communications and Information Sciences
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• 제21권9호
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• pp.2470-2480
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• 1996

The energy efficiency and bandwidth efficiency are two important criterion in designing a modulation scheme Especially the constant envelope property must be considered as in the non-linear channel tht exit, for example in the nonlinear amplifiers for satellite repeater. The Q$^{2}$AM(Quadrature Quadrature Amplitude Modulation) is a new modulation scheme which combines the Q$^{2}$PSK(Quadrature Quadrature Phase Shift Keying) scheme which increases the signal space dimension and the QAM scheme which increases the bandwidth efficiency using the multi-level signal. The Q$^{2}$AM scheme has by far superior spectrum efficiency compared with the existing modulation schemes. Applying this scheme in the non-linear communication system increses the bandwidth efficiency but cannot envelop property. In this paper, a new system architecture is suggested which satisfies the large spectrum efficiency and constant envelope property by implementing the linear block coding prior to the Q$^{2}$AM modulation. the system has improved in performance by gaining the constant envelope and the additional coding gain. We able to observe the performance improvement of the suggested system(at BER=10$^{-5}$ ) of 4.4 dB for the 16-QAM and 0.7 dB for the Q$^{2}$PSK under the exact spectrum efficiency.

• Journal of the Korea Institute of Information and Communication Engineering
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• 제23권6호
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• pp.726-732
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• 2019

In this study, we proposed an asymmetric differential inductor to improve the linearity of differential power amplifiers. Considering the phase error between differential signals of the differential amplifier, the location of the center tap of the differential inductor was modified to minimize the error. As a result, the center tap was positioned asymmetrically inside the differential inductor. With the asymmetric differential inductor, the AM-to-AM and AM-to-PM distortions of the amplifier were suppressed. To confirm the feasibility of the inductor, we designed a 2.4 GHz differential CMOS PA for IEEE 802.11n WLAN applications with a 64-quadrature amplitude modulation (QAM), 9.6 dB peak-to-average power ratio (PAPR), and a bandwidth of 20 MHz. The designed power amplifier was fabricated using the 180-nm RF CMOS process. The measured maximum linear output power was 17 dBm, whereas EVM was 5%.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제42권2호
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• pp.75-80
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• 2005

In this paper, 2-stage power amplifier has been designed for 5.8GHz wireless LAN application. The power amplifier PldB output power has 21.6dBm at 5.8GHz frequency. Also the power amplifier shows 17.6dB gain and -17.8dB input return loss at 5.725GHz to 5.825GHz. The OFDM modulation and transmission block have been modeled in order to analyse the relationship between the power amplifier distortion and output ACPR for the IEEE 802.11a wireless LAN. The nonlinear characteristic of the power amplifier has been modeled as AM-to-AM and AM-to-PM using the behavioral model, and the output spectrum is analysed with the phase distortion variation. Also, amplifier back-off value from PldB to satisfy the required IEEE 802.11a standard spectrum mask has been simulated with phase distortion, and the simulation data have been compared to the measurement result collected by using the pre-distortion technique.

• Korean Journal of Veterinary Service
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• 제30권3호
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• pp.329-338
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• 2007

Samples collected from 15 broiler farms(47 flocks, 920 1-day-old chicks) during March to December, 2006, To survey serum antibody titers of NDV, IBDV and MG/MS, the antibodies of ND viruses were detected by HI test and ELISA, against antibodies of IBD viruses and MG/MS by ELISA. The antibody titers of NDV showed 6.4, HI and 6,968, ELISA, respectively. The rate to below protective antibody levels(${\ge}5$, HI and ${\ge}1,000$, ELISA) were 8%, HI, 5%, ELISA, specially, Baeksemi were 22%, HI, 14%, ELISA. The rate of positive by ELISA showed 99%(914/920). The ELISA titer of IBDV showed mean titer 3,890. The rate of positive were 93% (857/920), specially, Baeksemi were 84%. The ELISA titers of MG/MS showed mean titer 5,666. The rate of positive were 78% (715/920) and 100%, Abor-Acre, 97%, Baeksemi, respectively. The antibodies not detected from 18%, ELISA titers was varied from 500 to 20,000. At antimicrobial susceptibility of E coli, Staphylococcus spp and Salmonella spp isolated from 1-day-old chicks, E coli were susceptible to AmC, AM, NOR, SXT, ENR, CIP, Staphylococcus spp were susceptible to AmC, SXT, AM, ENR and Salmonella spp were susceptible to AM, AmC, SXT and P.