• The Korean Journal of Mycology
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• v.20 no.3
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• pp.234-239
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• 1992

The experiment was performed to find out the possibilities to detect virus infection in oyster mushrooms, Pleurotus species by analysis of doublestranded ribonucleic acid (ds RNA). Ds RNA segments were extracted from virus infected isolates which grew abnormally. But virus free isolates didn't show any ds RNA segments. The ds RNA was consisted of one large segment of 8100 base pairs (bp) and 4 smaller segments with 2170, 2120, 1980 and 1984 bp. Whereas, cell free virus particles showed only one larger ds RNA segment. The ds RNA was dissolved by RNase A in low salt, 0.1 M SSC and melted at $85^{\circ}C$. It was possible to use the ds RNA analysis for detecting virus infection directly from the host cells.

• 전자공학회논문지 IE
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• v.43 no.2
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• pp.70-74
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• 2006

The performance of conventional direct sequence code division multiple access (DS-CDMA) systems is decreased under environments such as additive white Gaussian noise (AWGN), channel distortion and interference noise due to multiple access user. By means of this parameter, auto correlation value of pseudo noise spreading sequence is decreased at receiver. This techniques which are based on correlation of between signature waveform signal. In this paper, to improve correlation property, we proposed the binary chirp DS-CDMA techniques which combine the DS-CDMA and chirp modulation. The proposed system which is based on binary chirp symbol has a good correlation value. Thus, we called BC DS-CDMA. To evaluate the system's performance, we compare the performance of the proposed systems with DS-CDMA systems under AWGN channel and halogen noise which exists on the powerline. The simulation results show that the proposed method has better performance than conventional technique.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.3
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• pp.178-185
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• 2014

Purpose: The use of dietary supplements (DS) has increased in most nations. We investigated the amount of DS intake in the Korean population by analyzing a national survey, to support the preparation of a national institutional strategy regarding DS intake and marketing. Methods: The data of the fifth Korea National Health and Nutrition Examination Survey (a year between 2010 and 2012) were investigated, analyzing the rate of DS intake, and the characteristics of the intake group and non-intake group in Korean preschool children. Results: The intake rate of DS was 49.0-54.2% (1,313,874-1,491,240) and 19.6-30.3% (250,603-421,922) in children from 1 to 6 years old and in those less than 1 year, respectively, from 2010 to 2012. The highest intake rate was observed in the age group of five. The mean age was significantly higher in the DS intake group than in the non-intake group. Intake of essential nutrients, minerals, and vitamins were also higher in the DS intake group. The level of family income was significantly associated with the intake rate (p<0.001). In children less than 1 year, probiotics accounted for the highest intake of DS. Conclusion: Korean preschool children have high consumption of DS. Therefore, problems may arise from the waste of money purchasing unnecessary DS, and from the overuse of DS in preschoolers who do not require DS intake. We hope these results can be used to produce an appropriate national institutional strategy regarding DS intake and marketing.

• Korean Journal of Microbiology
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• v.33 no.2
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• pp.105-110
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• 1997

Ustilago maydis strains (A-series and SH-series) containg virus or viral dsRNAs were artificially mated in corn seedling to generate 6 progeny strains, designated A23, A45, A21l, A31O, SH24 and SH61O. The dsRNA patterns of progeny strains were identical to those of the parental strains and there was no molecular exclusion mechanism among dsRNAs of parental strains. Virus particles were purified from 6 progeny strains and viral dsRNAs were analyzed on 5% PAGE. There was no mixed encapsidation between virus or dsRNAs of parental strains. Progeny strain SH6l4 produced toxin which inhibits the growth of SH9, SHIO and SH11. Likewise, toxins from A310 and SH24 inhibited growth of the SH11 strains. These results indicate that the presence of different types of dsRNA does not interfere the expression of toxin gene.

• Microbiology and Biotechnology Letters
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• v.30 no.4
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• pp.346-351
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• 2002

A bacterium producing the neutral pretense was isolated from soil, and was identified as Bacillus sp. DS-1 by 16S rRNA sequence comparison and biochemical determinations. The production of protease from Bacillus sp. DS-1 was increased 20% and 30% by the additions of 1% glucose and 1% yeast extract, respectively. The optimum pH and temperature for the protease activity were pH 7.0 and 55$^{\circ}C$. Bacillus sp. DS-1 produced a metalloprotease as a major protease in culture medium, since the pretense activity in culture supernatant was inhibited by the presence of 1 mM EDTA significantly.

• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.5
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• pp.23-33
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• 2008

In this paper, we verify the performance of LDPC coded OFDM/DS system by Monte-Carlo simulation of BER on Eb/No. The simulation results show that LDPC coded OFDM/DS has a strong anti-jamming characteristic over pulse-noise jammer and partial-band noise jammer. The performance of LDPC coded OFDM/DS system is evaluated on both faded waveforms and non-faded waveforms. For non-faded waveforms, high coding gain is attained due to LDPC, even when waveforms have short PN sequence and JSR is only 5dB. Especially, the increase in the repeated number of LDPC decoding enhances coding gain. However, faded waveforms cannot achieve sufficient average effect when PN sequence is short. High coding gain of faded waveforms can be achieved by extending length of PN sequence. In addition, we compare LDPC coded OFDM/DS system with Convolutional coded OFDM/DS system. The simulation results illustrate that when LDPC coded OFDM/DS system with short PN sequence has sufficient average effects, the system shows lower BER than Convolutional coded OFDM/DS system with long PN sequence.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.10 no.6
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• pp.835-846
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• 1999

In this experiment I have made FM-DS/SS system replacing 170.120 MHz by utilizing FM transmitter and receiver. In the transmitter, the result shows that the modulated FM-DS/SS signal is a typical $(sin \chi/\chi)^2$ spectrum by using the clock(1.329 MHz) of PN divided from FM carrier. In the receiver, SO(Synchronous Oscillator) was applied to despread. Like figure 1, 2, and 4 when I applied SO, which consists of sliding correlator, to synchronous a favorable properties could be obtained in the receiver of FM-DS/SS system. In this paper, I used SO in order to take synchronous in the construction of FM-DS/SS system, and to support it I presented the result of the experiment on synchronous curve and properties of OS.

• Information and Communications Magazine
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• v.13 no.11
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• pp.181-191
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• 1996

In this paper we discuss narrow-band interference rejection schemes for spectrum overlay communications where direct sequence spread spectrum (DS/SS) communication system and narrow-band communication systems share the same frequency band. In this case, it is essential to reject the narrow-band signals to guarantee the performance of DS/SS system, while it is not necessarily required to reject the DS/SS signal to recover the narrow-band signal. We discuss several schemes such as time domain processing, frequency domain processing and exploiting the device characteristics to reduce the effect of narrow-band signal on DS/SS communication systems. Furthermore, we suggest a structure of tunable notch filter using gyrator that can easily be customized to ASIC.

• The KIPS Transactions:PartC
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• v.12C no.2 s.98
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• pp.223-228
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• 2005

The existing mobile communication system called DS/CDMA system, which is serviced widely nowadays, has some problems such as the severe ISI and multiple access interferences under the multi-path fading channel when applied to high-speed data transmission like multimedia transmission. To compensate these problems, we propose a sub-code multi-code hybrid DS/FH (Frequency Hopping) SS (Spread Spectrum) System by combining the multi-code system that restrains the multiple access interference with the hybrid DS/FH SS technique that reduces ISI(Intersymbol Interference) effect for high-speed transmission. Moreover, we implement and propose the sub-code technique to remedy the problems of the generic multi-code system. To verify the performance of the proposed system, the computer simulations are executed under the various channel environments.

• Safety and Health at Work
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• v.14 no.4
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• pp.431-437
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• 2023

Background: Depressive symptoms (DS) can erode physical and mental health; social support (SS) is considered a buffer for DS and a promoter for improving coping and recovery abilities. However, there is almost no research on the mediating role of negative coping (NC) in SS and DS, especially among firefighters. Methods: A cross-sectional survey was conducted among firefighters in Chongqing, China, and the valid data of 407 firefighters were collected through questionnaires distributed on the WeChat platform in 2020. Statistical Product and Service Solutions (SPSS) 26.0 is used for descriptive statistics and correlation analysis. Structural equation modeling was adopted to analyze the association among SS, NC, and DS. The mediation effect is also evaluated. Results: Firefighters' detection rate of DS is 23.3%, and when they receive more SS were less likely to develop DS. NC was positively correlated with DS (β = 0.54, p < 0.001) after controlling for SS. Besides, the results of structural equation modeling showed that NC partially mediates the relationship between SS and DS (standard error = 0.039, indirect effects = 0.109, 95% confidence interval: 0.047-0.200 p < 0.001). Conclusion: NC has a partial indirect effect between SS and DS among firefighters. SS could not only affect DS directly but also indirect work on it by affecting NC. This discovery will be a novel and meaningful part of the research on the firefighter population.