• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04a
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• pp.139-142
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• 2000

Influence of frequency and duty ratio on electro-optical characteristics are experimentally investigated in surface AC plasma display panels(AC-PDPs) by using the VDS(Versitile Driving Simulator)., in which electrode gap and width are 100 ${\mu}m$ and 260 ${\mu}m$, respectively. The filling gas is Ne-Xe gas mixture, and total pressure 400 Torr. It is found that the response time gets to be fast from 450 ns to 150 ns as pulse-off time of the sustain pulse decreases from 2 ${\mu}s$ to 0.2 ${\mu}s$. Also it is found that the IR(Infra Red) intensity and the luminous decreases as pulse-off time of the sustain pulse increases from 0.2 ${\mu}s$ to 2 ${\mu}s$.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.1
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• pp.197-204
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• 2010

This paper proposes a new body-effect compensated switch configuration for low voltage and low distortion switched-capacitor (SC) applications. The proposed circuit allows rail-to-rail switching operation for low voltage SC circuits and has better total harmonic distortion than the conventional bootstrapped circuit by 19 dB. A 2-1 cascaded sigma-delta modulator is provided for performing the high-resolution analog-to-digital conversion on audio codec in a communication transceiver. An experimental prototype for a single-stage folded-cascode operational amplifier (opamp) and a 2-1 cascaded sigma-delta modulator has been implemented m a 0.25 micron double-poly, triple-metal standard CMOS process with 2.7 V of supply voltage. The 1% settling time of the opamp is measured to be 560 ns with load capacitance of 16 pF. The experimental testing of the sigma-delta modulator with bit-stream inspection and analog spectrum analyzing plot is performed. The die size is $1.9{\times}1.5\;mm$.

• Journal of Chest Surgery
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• v.32 no.3
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• pp.294-298
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• 1999

Background: Video-assisted thoracoscopic surgery(VATS) has been established as a new method for treatment of spontaneous pneumothorax. We compared the clinical results of VATS with those of thoracotomy performed during the recent 5 years. Material and Method: We analyzed 126 patients whose medical records were available among the 154 patients who underwent operations for spontaneous pneumothorax from 1992 to 1996. The mean age was 27.1 years(15 to 75 years). 87 patients were operated on by VATS(Group A) and the other 39 by thoracotomy(Group B). The mean follow-up period was 14.7 months. Result: The operation time was shorter in group A than in group B(90.6${\pm}$38.6minutes: 117.2${\pm}$58.9minutes, p<0.05). The duration of postoperative hospital stay was shorter in group A than in group B(6.7${\pm}$4.2: 9.4${\pm}$3.3 days, p<0.05). The amount of analgesics(nalbuphin HCl, ketoprofen) used postoperatively were 2.4${\pm}$2.8 ampules in group A, which is less than the 6.5${\pm}$5.6 ampules in group B(p<0.05). The number of staples used in group A was smaller(2.7${\pm}$1.3 in group A, 1.76${\pm}$1.1 in group B, p<0.05). The duration of chest tube indwelling(4.3${\pm}$4.0 days in group A, and 5.6${\pm}$3.0 days in group B, NS), the recurrence rate(13.8% in group A, 2.6% in group B, NS), and the duration of air leakage(1.3${\pm}$3.3 days in group A, and 1.0${\pm}$2.5days in group B, NS) were not statistically different between the two groups. Conclusion: The application of VATS for the treatment of spontaneous pneumothorax has brought in better clinical results(shorter operation time, shorter hospital stay, less pain, and better cosmetic merits) than the thoracotomy without increasing any morbidity. However no advantages in recurrence rates and duration of postoperative air leakages are revealed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.2B
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• pp.203-209
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• 2004

In OBS networks, the burst dropping due to contention significantly affects the performance of TCP, but existing drop policies have not considered this problem and researches related to TCP have been mainly studied on burst assembling. We propose the drop policy considering retransmission of TCP to improve the performance of TCP in OBS networks. The proposed drop policy is the Retransmission Count-based DP that regards retransmission count of bursts as priority when it selects dropping burst. This paper evaluates the performance of RC-based DP model and general DP model using ns-2. The metrics of performance evaluation are TCP throughput, maximum sequence number of received TCP packets and drop rate of packet as simulation time increases.

• Journal of information and communication convergence engineering
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• v.11 no.3
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• pp.147-152
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• 2013

A novel balun being the structure of a Wilkinson power divider is suggested and fabricated. One of the power dividing paths in the suggested balun uses a conventional ${\lambda}/4$ transmission line for $-90^{\circ}$ phase shifting, and the other path uses a composite right/left-handed -${\lambda}/4$ transmission line for $+90^{\circ}$ phase shifting with four series capacitors and three parallel inductors. In addition, the suggested balun uses two $50-{\Omega}$ resistors and a conventional $50-{\Omega}$ transmission line of ${\lambda}/2$ electrical length between the two output ports, achieving good isolation and reflection values of two balanced ports. The suggested balun is simulated by the advanced design system simulation program and fabricated on TLX-9 20-mil substrate. The fabricated balun has a very good values of $S_{11}$ = -27.46 dB, $S_{21}$ = -3.40 dB, and $S_{31}$ = -3.28 dB, a phase difference of $-179.5^{\circ}$, a magnitude difference of 0.12 dB, and a delay difference of 0.1 ns, with $S_{22}$ = -36.28 dB, $S_{33}$ = -27.19 dB, and $S_{32}$ = -25.2 dB at 1 GHz, respectively.

• Journal of Korean Public Health Nursing
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• v.15 no.2
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• pp.239-248
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• 2001

The purpose of this study was to analyze risk factors for nosocomial pneumonia in patients admitted to NS ICU, and to provide a basic data to decrease respiratory nosocomial infection rate engendered from medical environments in NS ICU. The study site was the NS ICU at a university hospital located in Seoul, Korea. The subjects were 31 patients diagnosed with nosocomial pneumonia, who were selected from the initial list of 300 potential subjects who had been a) admitted between September 1999 and January 2000, and September 2000 and January 2001, b) resided at the NS ICU over 72 hours. The diagnostic standard of nosocomial pneumonia was based on the nosocomial infection guides of C university hospital. The data were analyzed using frequencies and logistic regression analysis. The sputums obtained from the subjects were cultivated and causal viruses were separated. The results were as follows: 1. The nosocomial pneumonia rate was $10.3\%$. There were 7 types of causal viruses separated from the sputum. and the most prevalent type of virus was MRSA as $62.2\%$. 2. The factors significantly influencing the incidence of nosocomial pneumonia included age, the residential duration at the NS ICU, GCS scores, diabetes mellitus, insertion of tracheal tube and its duration, tracheostomy and its length of insertion, the use of artificial ventilator and the length of its use, and the insertion of naso-gastic tube. The most significant risk factor among these was the insertion of tracheal tube (odds ratio=18.684. $95\%$ CI=6.849-50.974), followed by the use of tracheostomy (odds ratio=15.419, $95\%$ CI=6.615-35.942), the insertion of naso-gastric tube (odds ratio=14.875, $95\%$ CI=6.396-34.595), and the use of artificial ventilator (odds ratio=13.000. $95\%$ CI=5.633­30.001). 3. Regarding the use of the mechanical aids, the insertion of tracheal tube resulted in 12.968 times increase of the nosocomial pneumonia rate, and the use of artificial ventilator lead 6.714 times increase of the nosocomial pneumonia rate. One point increase of the GCS score resulted in the 1.210 times increase of the nosocomial pneumonia rate. For patients who had tracheal tube, tracheostomy, and artificial ventilator, one day increase of their residential duration at NS ICU lead 1.073 times increase of the nosocomial pneumonia rate. 4. In terms of duration of the mechanical aid usage, one day increase in the use of artificial ventilator engendered 1.080 times increase in the nosocomial pneumonia rate. One day increase of the residential duration at the NS ICU lead 1.604 times increase in the nosocomial pneumonia rate. As one point of the GCS score increased, 0.876 times decrease of the nosocomial pneumonia rate was reported. These study findings show that the risk factors significantly influencing the incidence of nosocomial pneumonia include the use of tracheal tube, tracheostomy, naso-gastic tube, and artificial ventilator. It is recommended that nurses working at NS ICU should pay more attention to the patients with these factors as the risky group for the nosocomial pneumonia, and thus make more active efforts to provide nosocomial pneumonia prevention strategies for them. In further studies patients admitted to the different types of ICUs such as internal medicine or surgery unit ICU will be also included, and more wide investigation of nosocomial pneumonia risk factors will be conducted through one-year longitudinal follow up.

• Journal of Embryo Transfer
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• v.31 no.4
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• pp.367-374
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• 2016

This study was conducted to evaluate the effect of transfer temperature of epididymis on survival rate of semen and development ability of B6D2F1 mice embryos. No significant differences were noted in the survival rate of semen ($59.0%{\pm}0.1$ vs. $47.6%{\pm}0.1$), in vitro fertilization rate ($90.7%{\pm}0.1$ vs. $90.7%{\pm}0.1$), developmental rate ($90.0%{\pm}0.1$ vs. $90.0%{\pm}0.1$), and blastocysts formation rate ($53.1%{\pm}0.2$ vs. $52.3%{\pm}0.2$) between groups. (NS; P>0.05). However, the zona hatched rate was significantly higher in the $4^{\circ}C$ group compared to those of the $37^{\circ}C$ group ($47.8%{\pm}0.1$ vs. $25.6%{\pm}0.2$; p<0.05). When it comes to cell numbers of blastocysts, the % ICM (/total cells) was significantly higher in the group of $4^{\circ}C$ compared to the $37^{\circ}C$ ($27.0%{\pm}0.1$ vs. $18.3%{\pm}0.1$; p<0.05). However there were no differences in total cell numbers ($72.7{\pm}31.6$ vs. $62.0{\pm}36.6$), ICM cell numbers ($17.0{\pm}7.8$ vs. $14.6{\pm}8.6$), TE cell numbers ($55.8{\pm}29.8$ vs. $64.0{\pm}24.4$), the ratio of ICM:TE ($1:4.2{\pm}4.1$ vs. $1:6.4{\pm}7.2$) between two groups (NS; P>0.05). Taken altogether, it is expected to achieve the best developmental ability of B6D2F1 mice embryos in the transfer temperature of epididymis. Also these results can provide fundamental data to maximize culture condition for in vitro fertilization on B6D2F1 mice. In future, therefore, it is expected that results herein might be applied for in vitro culture of human embryos.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.5 s.347
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• pp.162-168
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• 2006

Understanding of propagation characteristics is very important for the wireless communication system design and wireless communication service construction. In this paper, propagation characteristics is measured and analyzed at 2.45Ghz frequency band under curved subway tunnel environment. We constituted channel measurement system with sliding correlation and five different kind of antennas. The purpose of five different type of antennas is to compare propagation characteristics according to beam shape of antennas. The path loss under tunnel environment is average $4.38^{\sim}14.41dB$ lower than free space and circular polarization antenna marked smallest path loss. Also, path loss is smallest when the receiver antenna located outside of tunnel in th curved section. 90% of delay components of all antennas measured within 20ns and directional antenna has more wide coherence bandwidth than omni-directional antenna. According to measured result, when we consider path loss and delay characteristics, circular polarization antenna is most suitable under tunnel environment.

• Korean Journal of Poultry Science
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• v.45 no.3
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• pp.209-217
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• 2018

The innate immune recognition is based on the detection of microbial products. Toll-like receptors (TLRs) located on the cell surface and the endosome senses microbial components and nucleic acids, respectively. Chicken TLRs mediate immune responses by sensing ligands from pathogens, have been studied as immune adjuvants to increase the efficacy of vaccines. Single nucleotide polymorphisms (SNPs) of TLR3 and TLR4 genes in chicken were associated with resistance and susceptibility to viral infection. In this study, SNPs of chTLR3 and chTLR4 genes were retrieved from public database and annotated with chicken reference genome. Three-dimensional models of the chTLR3 and chTLR4 proteins were built using a Swiss modeler. We identified 35 and 13 nsSNPs in chTLR3 and chTLR4 genes respectively. Sorting Intolerant from Tolerant (SIFT) and Polymorphism Phenotyping v2 (Polyphen-2) analyses, suggested that, out of 35 and 13 nsSNPs, 4 and 2 SNPs were identified to be deleterious in chTLR3 and chTLR4 gene respectively. In chTLR3, 1 deleterious SNP was located in ectodomain and 3 were located in the Toll / IL-1 receptor (TIR) domain. Further structural model of chTLR3-TIR domain suggested that 1 deleterious SNP be present in the B-B loop region, which is important for TIR-TIR domain interactions in the downstream signaling. In chTLR4, the deleterious SNPs were located both in the ectodomain and TIR domain. SNPs predicted for chTLR3 and chTLR4 in this study, might be related to resistance or susceptible to viral infection in chickens. Results from this study will be useful to develop the effective measures in chicken against infectious diseases.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.8
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• pp.663-671
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• 2013

Recently, the Wi-Fi Direct standard based on WLAN is getting more attention as a new technology for enabling D2D(Devide-to-Device) communications on mobile devices. However, due to limited power resource of mobile devices and, an energy inefficiency problem can be an issue. In order to solve this problem, the Wi-Fi Direct defines two power management schemes: Opportunistic scheme and Notice of Absence(NoA) scheme. However, there is no concrete description of which power management scheme would be better for when. In this paper, via comprehensive simulation studies using ns-3, we show that each scheme presents obviously different performance and energy efficiency according to data traffic patterns. We then propose more energy efficient way of dynamically switching the two power management schemes.