• Proceedings of the Korea Multimedia Society Conference
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• 2004.05a
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• pp.421-424
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• 2004

음성 중심의 기존 2G CDMA/PCS 시스템과 달리 CDMA2000 및 1xEV-DO와 같은 차세대 이동통신 시스템에서 패킷 데이터 서비스가 부각됨에 따라 효율적인 망의 설계 및 디멘져닝을 위해서는 무엇보다도 데이터 트래픽의 주요 특성인 버스트(Burst)와 자기유사성(Self-similarity)이 반영된 모델이 요구된다. 본 논문에서는 차세대 이동통신 시스템에서 자기유사 특성을 갖는 트래픽의 큐잉 성능을 시뮬레이션 하였고, 그 결과를 해석적 모델과 비교하였다. 또한 Crossover point의 변화와 출력링크의 변화도 분석하였다.

• Journal of Ginseng Research
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• v.38 no.3
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• pp.173-179
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• 2014

Background: Ginsenosides are the major components responsible for the biochemical and pharmacological actions of ginseng, and have been shown to have various biological activities. In this study, we investigated the antiviral activities of seven ginsenosides [protopanaxatriol (PT) type: Re, Rf, and Rg2; protopanaxadiol (PD) type: Rb1, Rb2, Rc, and Rd)] against coxsackievirus B3 (CVB3), enterovirus 71 (EV71), and human rhinovirus 3 (HRV3). Methods: Assays of antiviral activity and cytotoxicity were evaluated by the sulforhodamine B method using the cytopathic effect (CPE) reduction assay. Results: The antiviral assays demonstrated that, of the seven ginsenosides, the PT-type ginsenosides (Re, Rf, and Rg2) possess significant antiviral activities against CVB3 and HRV3 at a concentration of $100{\mu}g/mL$. Among the PT-type ginsenosides, only ginsenoside Rg2 showed significant anti-EV71 activity with no cytotoxicity to cells at $100{\mu}g/mL$. The PD-type ginsenosides (Rb1, Rb2, Rc, and Rd), by contrast, did not show any significant antiviral activity against CVB3, EV71, and HRV3, and exhibited cytotoxic effects to virus-infected cells. Notably, the antiviral efficacies of PT-type ginsenosides were comparable to those of ribavirin, a commonly used antiviral drug. Conclusion: Collectively, our findings suggest that the ginsenosides Re, Rf, and Rg2 have the potential to be effective in the treatment of CVB3, EV71, and HRV3 infection.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.1
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• pp.63-70
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• 2024

Lithium-ion batteries (LIB) are widely used in various sectors, such as transportation (e.g., electric vehicles (EV)) and energy (e.g., energy storage facilities) due to their high energy density, broad operating temperature (-20 ℃ ~ 60 ℃), and high capacities. LIBs are powerful but fragile on external factors, including pressure, physical damage, overheating, and overcharging, that cause thermal runaway causing fires and explosions. During a LIB fire, a large amount of oxygen is generated from the decomposition of ionogenic materials. A water fire extinguisher that helps with cooling and suffocating must be essentially required at the same time. In fact, however, it is difficult to suppress LIB fires in the case of EVs because a LIB is installed with a battery pack housing that interrupts direct extinguishing by water. Thus, this study aims to investigate effective fire extinguishing measurements for LIB fires by using an EV. Relevant documents, including research articles and reports, were reviewed to identify effective ways of LIBs fire extinguishing. A real-scale fire experiment generating thermal runaway was carried out to figure out the combustion characteristics of EVs. This study revealed that the most effective fire extinguishing measurements for LIB fires are applying fire blankets and water tanks. However, there is still a lack of adequate regulation and guidelines for LIB fire extinguishment. Taking this into account, developing functional fire extinguishment measurements and available regulatory instruments is an urgent issue to secure the safety of firefighters and citizens.

• Clinical and Experimental Reproductive Medicine
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• v.48 no.3
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• pp.245-254
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• 2021

Objective: In humans, polycystic ovary syndrome (PCOS) is an androgen-dependent ovarian disorder. Aberrant gene expression in folliculogenesis can arrest the transition of preantral to antral follicles, leading to PCOS. We explored the possible role of altered gene expression in preantral follicles of estradiol valerate (EV) induced polycystic ovaries (PCO) in a mouse model. Methods: Twenty female balb/c mice (8 weeks, 20.0±1.5 g) were grouped into control and PCO groups. PCO was induced by intramuscular EV injection. After 8 weeks, the animals were killed by cervical dislocation. Blood serum (for hormonal assessments using the enzyme-linked immunosorbent assay technique) was aspirated, and ovaries (the right ovary for histological examinations and the left for quantitative real-time polymerase) were dissected. Results: Compared to the control group, the PCO group showed significantly lower values for the mean body weight, number of preantral and antral follicles, serum levels of estradiol, luteinizing hormone, testosterone, and follicle-stimulating hormone, and gene expression of TGFB1, GDF9 and BMPR2 (p<0.05). Serum progesterone levels were significantly higher in the PCO animals than in the control group (p<0.05). No significant between-group differences (p>0.05) were found in BMP6 or BMP15 expression. Conclusion: In animals with EV-induced PCO, the preantral follicles did not develop into antral follicles. In this mouse model, the gene expression of TGFB1, GDF9, and BMPR2 was lower in preantral follicles, which is probably related to the pathologic conditions of PCO. Hypoandrogenism was also detected in this EV-induced murine PCO model.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.4
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• pp.401-406
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• 2017

In this study, using the VITEK 2 system, 74 samples (22.6%) out of 327 specimens were identified by the growth of Enterococcosel media (EV6 agar) supplemented with $6{\mu}g/mL$ of vancomycin. Enterococcus faecium was identified as 55 strains (74.3%), Enterococcus casseliflavus as 2 strains (2.7%), Enterococcus avium as 1 strain (1.4%), and Enterococcus gallinarum as 16 strains (21.6%). Among the 55 phenotypes of Enterococcus faecium, 42 (76.4%), 9 (16.4%), and 4 strains (7.3%) showed the vanA, vanB, and vanC phenotype, respectively. The 16 strains of Enterococcus gallinarum and 2 strains of Enterococcus casseliflavus showed the vanC phenotype and the 1 strain of Enterococcus avium had the vanB phenotype. The one strain of Enterococcus faecium propagated only in EV4 and was susceptible to both vancomycin and teicoplanin according to the antimicrobial susceptibility test using the VITEK 2 system. The vancomycin resistance phenotype gene was not detected by PCR. A total of 327 specimens were cultured in Enterococcosel broth supplemented with $6{\mu}g/mL$ of vancomycin (EV6 broth), and 120 strains (36.7%) were isolated. These 120 strains were subjected to vancomycin resistant genotyping by a multiplex real-time polymerase chain reaction and 51 strains (42.5%) showed vanA; 5 strains (4.2%) showed vanA and vanC; and 18 strains (15%) showed vanC. Vancomycin resistance genotypes were not detected in the remaining 46 strains (38.3%).

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.3
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• pp.60-74
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• 2008

Purpose: This study was designed to investigate the effects of Gwibi-Tang(GBT) on the polycystic ovary(PCO) induced by estradiol valerate(EV) in rats. Methods: PCO was induced by single intramuscular injection with EV(4mg) in female rats. Normal group(n=8) were injected with sesame oil and orally administrated distilled water for eight weeks. PCO control group(n=8) were injected with EV and orally administrated distilled water for eight weeks. GBT treated group(n=8) were injected with EV and orally administrated GBT for eight weeks. Then we measured weight of body, ovaries, adrenal glands, and uterus of rats. The histopathology changes of ovaries were also evaluated. The expression of nerve growth factor(NGF) was analyzed in the central nervous system, adrenal glands and ovaries by immunohistochemistry. And also CRF expression in median eminance of Rats were analyzed. Results: 1. The weight(g) of rats in GBT treated group($275{\pm}14$) was significantly increased(p<0.01) compared with control group($253{\pm}8$), 2. The weight(mg) of ovaries in GBT treated group($75.8{\pm}16.7$) was significantly increased(p<0.001) compared with control group($37.4{\pm}6.7$). 3. The number of mature follicles in GBT treated group($3.6{\pm}1.2$) was significantly increased(p<0.01) compared with control group($1.5{\pm}1.5$. 4. The number of atretic follicles in GBT treated group($8.0{\pm}3.1$) was significantly decreased(p<0.01) compared with control group($18.6{\pm}6.0$). 5. The number of cystic follicles in GBT treated group($0.5{\pm}0.5$) was significantly increased(p<0.01) compared with control group($2.3{\pm}1.3$). 6. The number of corpora lutea in GBT treated group($6.1{\pm}3.9$) was significantly increased(p<0.01) compared with control group($1.6{\pm}2.3$). 7. The expression of NGF-immunoreactive cells in the ovarian granulosa cells in GBT treated group was lesser observed than control group. Conclusion: From the above results, we concluded that Gwibi-Tang has inhibitory effect on the development of EV-induced polycystic ovary. And it's effect may be related with decreased NGF activities in the ovary.

• The Transactions of the Korean Institute of Power Electronics
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• v.24 no.6
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• pp.438-444
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• 2019

In this paper, bidirectional LLC resonant DC/DC converters with the primary auxiliary windings in transformers of resonant circuits are proposed. Although the resonant capacitors are used on both the primary and secondary sides, regardless of the direction of power flow, the main feature of the proposed converters exhibits high gain characteristics without any mutual coupling between the resonant capacitors. For one of the proposed converters, an investigation of the operating characteristics in each mode has been carried out. A prototype of a 3.3 kW bidirectional LLC resonant converter for interfacing 750 V DC buses has been built and tested to verify the validity and applicability of the proposed converter.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.7-8
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• 2011

최근 하이브리드 및 전기자동차의 집약적인 발전과 함께 충전기술이 대두 되고 있다. 본 논문은 충전기능만을 고려한 단방향 충전시스템에서 양방향 배터리 충/방전 시스템에 대하여 서술한다. 양방향 시스템은 주차 된 차량의 배터리를 저장 매체로 활용하여 V2G(Vehicle to Grid)기술로 활용할 수 있어 잉여전력에 대해서 계통으로 전력을 전송할 수 있다. 용량은 가정용으로써 3.3kW 탑재형 단상 양방향 충/방전기에 대한 시뮬레이션과 실험을 통해 결과를 도출했다.

• Proceedings of the KIEE Conference
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• 1992.07b
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• pp.1182-1184
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• 1992

In case of chopper control is used for the d.c motor In the electric vehicle(EV) in general step down chopper is used for the driving and the step-up chopper is used for the regeneration. Bilateral variable ratio chopper system(BVRCS) formed by parallel combination of upper two chopper methods step-down, step-up and step-up/down chopper operations by duty cycle, circuit element and driving condition. In this paper, BVRCS is proposed for the simulated and experimented control of d.c motor in the EV. By the result of simulation BVRCS represents same driving power compared to the step-down and excellent breaking power compared to the step-up chopper system because of the greater motor current.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.757-758
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• 2006

The research is being made on the oncoming generation hybrid EV and FECV in view of energy efficiency and environment. In the future the research will be addressed on the automobile electromotive compression motor and driver which have important competitive points. In this paper, a new method that can presume location of the BLDC Moto rotor of electromotive compressor was proposed, the driver of BLDC motor was made and the possibility that it can be used in the air compressor of EV was proved.