• Journal of Power Electronics
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• 제17권6호
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• pp.1563-1576
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• 2017

This paper presents a novel switching pattern current control (SP-CC) scheme, which is applied in three-phase voltage-source converters (VSCs). This scheme can select the optimal output switching pattern (SP) by referring the basic principle of space vector modulation (SVM). Moreover, SP-CC is a method without a carrier wave. Thus, the implementation process is concise and easy. When compared with the conventional hysteresis current control (C-HCC) and the space vector-based hysteresis current control (SV-HCC), the SP-CC has the performances of faster dynamic response of C-HCC and less switching number (SN) of SV-HCC. In addition, it has less harmonic contents in the three-phase current, along with a lower switching loss and a higher efficiency. Moreover, the hysteresis bandwidth and Clarke conversion are not required in the SP-CC. The effectiveness of the presented SP-CC is verified by simulation and experimental test results. In addition, the advantages of the SP-CC, when compared with the C-HCC and SV-HCC, are verified as well.

• 한국운동역학회지
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• 제27권3호
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• pp.211-217
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• 2017

Objective: The purpose of this study was to investigate the effect of a 12-week professional body massage program (PMP) on forward head posture, neck pain, and plantar foot pressure balance in men in their 20s. Method: A total of 20 men with musculoskeletal diseases were recruited for this study. The participants were asked to take part in a PMP twice a week for 12 weeks. The cranial vertical angle (CVA) for forward head posture and visual analogue scale (VSC) for neck pain and right/left foot plantar pressure balances were extracted to compare between pre- and post-program differences. Results: CVAs before ($56.86{\pm}4.55^{\circ}$) and after ($62.72{\pm}4.57^{\circ}$) and VSCs before ($6.95{\pm}1.70$) and after ($1.70{\pm}1.56$) PMP revealed statistically significant differences. The right foot, after PMP, showed a significant increase in the plantar pressure balance from $46.17{\pm}2.95$ to $49.44{\pm}1.29%$, while the left foot decreased significantly from $53.83{\pm}2.95%$ to $50.56{\pm}1.29%$. Therefore, based on these results, it may be said that the foot pressure balance abilities were improved after PMP because the ideal foot pressure ratio is 50%. Conclusion: Consequently, it was suggested that a 12-week PMP could be utilized for improvement of forward head posture, neck pain, and foot plantar pressure balance in men in the 20s with musculoskeletal diseases.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.391-400
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• 2008

Multi-pulse topology of converters using elementary six-pulse GTO - VSC (gate turn off based voltage source converter) operated under fundamental frequency switching (FFS) control is widely adopted in high power rating static synchronous compensators (STATCOM). Practically, a 48-pulse ($6{\times}8$ pulse) configuration is used with the phase angle control algorithm employing proportional and integral (PI) control methodology. These kinds of controllers, for example the ${\pm}80MVAR$ compensator at Inuyama switching station, KEPCO, Japan, employs two stages of magnetics viz. intermediate transformers (as many as VSCs) and a main coupling transformer to minimize harmonics distortion in the line and to achieve a desired operational efficiency. The magnetic circuit needs altogether nine transformers of which eight are phase shifting transformers (PST) used in the intermediate stage, each rating equal to or more than one eighth of the compensator rating, and the other one is the main coupling transformer having a power rating equal to that of the compensator. In this paper, a two-level 48-pulse ${\pm}100MVAR$ STATCOM is proposed where eight, six-pulse GTO-VSC are employed and magnetics is simplified to single-stage using four transformers of which three are PSTs and the other is a normal transformer. Thus, it reduces the magnetics to half of the value needed in the commercially available compensator. By adopting the simple PI-controllers, the model is simulated in a MATLAB environment by SimPowerSystems toolbox for voltage regulation in the transmission system. The simulation results show that the THD levels in line voltage and current are well below the limiting values specified in the IEEE Std 519-1992 for harmonic control in electrical power systems. The controller performance is observed reasonably well during capacitive and inductive modes of operation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(1)
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• pp.77-81
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• 2004

In this paper a novel line interactive UPS (Uninterruptible Power Supply) using the two 4-leg VSCs and AC line reactor is proposed. The 4-leg Voltage Source Converter(VSC) can use the DC link voltage effectively by the 3-D SVPWM method. Hence the DC battery voltage can be reduced by $15\%$ in comparison to that of the conventional line-interactive UPS system. One VSC is in parallel with the AC line reactor of the power source side, and the other is in series with the load. The parallel 4-leg voltage source inverter controls three-phase line voltage independently in order to control the line reactor current indirectly. It eliminates the neutral line current and the active ripple power of the source side using the pqr theory so that unity power factor and the sinusoidal source current can be achieved even though both the source and the load voltages have zero sequence components. The series 4-leg voltage source inverter compensates the line voltage and allows the load voltage to be balanced and harmonic-free. Both of parallel and series 4-leg voltage source inverters always act as independently controllable voltage sources, so that three-phase output voltage shows a seamless transition to the backup mode. The feasibility of the proposed UPS system has been investigated and verified through computer simulation results.

• Journal of Oral Medicine and Pain
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• 제39권2호
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• pp.63-68
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• 2014

Purpose: This study was designed to evaluate the sex and age differences in the Korean oral malodor patients. Methods: Subjects were the patients with oral malodor (male, 2,239; female, 3,496) visited the Department of Oral Medicine, Kyung Hee University Dental Hospital from January 2007 to December 2012 were recruited to this study and measured the volatile sulfur compounds (VSCs) in the oral cavity with Halimeter. Results: There were slightly more female than male (female : male=3 : 2), and the mean values of Halimeter result were 65.79 ppb (female) and 79.94 ppb (male), which was more higher in male. Total patients showed normal age distribution in both gender, and the peak was the age of 26-35 in female, the age of 36-45 in male. The percentages of pseudo-halitosis were 74.7% in female and 69.3% in male, which was more higher in female. Conclusions: Therefore, it was revealed that women are more likely to have oral malodor than men, and there was a difference in the largest age group between men and women. Also women had more pseudo-halitosis patient than men.

• Journal of Ginseng Research
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• 제34권2호
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• pp.122-131
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• 2010

This clinical study was performed to evaluate whether supplementation of proton pump inhibitor (PPI)-based triple therapy with Korean red ginseng can enhance Helicobacter pylori (H. pylori) eradication and reduce levels of halitosis-associated volatile sulfur compounds (VSCs) in the stomach. Seventy-six patients were randomized into an eradication regimen-only group (n=45) or an eradication regimen plus 10 weeks of Korean red ginseng supplementation group (n=31). The eradication regimen consisted of PPI b.i.d., clarithromycin 500 mg b.i.d., and amoxicillin 1 g b.i.d.. for seven days. Korean red ginseng supplementation commenced on the last day of the eradication regimen. $^{13}C$-urea breath test and halimeter measurements were performed prior to protocol repetition. By intention-to-treat analysis, the H. pylori eradication rate in the Korean red ginseng group (77.4%, 24 of 31) was higher than that in the control group (45.0%, 26 of 45). However, by per protocol analysis, the eradication rate in the Korean red ginseng group was significantly higher than that in the control group (92.3%, 24/26 vs. 69.4%, 26/38; p<0.05). H. pylori infection was significantly associated with increased VSC levels. However, VSC levels decreased significantly in the Korean red ginseng group (p<0.05). In conclusion, supplementation of triple therapy with Korean red ginseng increased the H. pylori eradication rate and led to significant reductions in VSC levels, suggesting the usefulness of this substance in combating H. pylori infection.

• Journal of Microbiology and Biotechnology
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• 제29권2호
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• pp.311-320
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• 2019

Fusobacterium nucleatum is a morbific agent in periodontitis and halitosis. Egg yolk antibody (IgY) was obtained from egg yolks from chickens stimulated with F. nucleatum. This study was to assess the effectiveness of IgY on periodontitis and halitosis caused by F. nucleatum in vitro and in vivo. The growth of F. nucleatum was inhibited (p <0.05) by different concentrations of IgY in vitro and the results of a Halimeter show volatile sulfur compounds (VSCs) were reduced to $904{\pm}57ppb$ at a concentration 40 mg/ml of IgY. The changes of fatty acids of F. nucleatum were determined using GC-MS. The scores for odor index of rat saliva were decreased. The major constituent of volatile organic compounds (VOCs) including short-chain acids decreased 46.2% in 10 mg/ml IgY, ammonia decreased 70% in 40 mg/ml IgY, while aldehydes and olefine ketones were almost unchanged. The ELISA assay revealed that IL-6 and TNF-${\alpha}$ were decreased after 4 weeks' IgY treatment. Morphometric (X-ray) and histological analyses (HE) showed that IgY reduced alveolar bone loss and collagen fibers became orderly in rat models. As a result, IgY may have the potential to treat periodontitis and halitosis.

• 대한화장품학회지
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• 제40권2호
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• pp.187-193
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• 2014

충치는 사람의 구강질환 중 가장 흔한 질환으로 Streptococcus mutans (S. mutans)균이 초기 충치를 형성하는데 매우 중요한 역할을 담당한다. Porphyromonas gingivalis (P. gingivalis)는 대표적인 구취 유발균으로 구취 형성에 중요한 휘발성 황화합물을 생성하는데 관여한다. 치주질환은 치은결체조직과 치조골의 파괴를 유발하여 치아의 상실을 초래할 수 있는 만성 염증성 질환으로 Prevotella intermedia (P. intermedia)가 원인균이다. 이번 연구에서는 cetylpyridinium chloride (CPC), sodium fluoride (NaF), 녹차 추출액, 솔잎 추출액을 유효성분으로 하는 마우스워시 제품을 사용하여 S. mutans 균을 포함, 구강질환 균으로 널리 알려진 P. gingivalis, P. intermedia 대해 항균 효과를 확인하고자 하였다. 그 결과 시험군의 경우 S. mutans, P. gingivalis 에 대해 30 s 내에 4.00 Log, 4.68 Log의 사멸력을 확인하였고, P. intermedia의 경우 30 s 2.40 Log, 60 s 2.70 Log 사멸력을 확인하였다. 또한 Dentocult SM Strip mutans (SM Strip) 염색방법을 적용하여 S. mutans 균의 감소여부를 시각적 자료로 쉽게 확인할 수 있었다. 이와 같은 결과를 통해 CPC, NaF, 녹차 추출액, 솔잎 추출액을 포함한 마우스워시 제품은 구강균 사멸을 통해 충치 및 구취와 같은 구강질환 예방에 효과가 있을 것으로 기대한다.

• 생명과학회지
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• 제23권3호
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• pp.443-447
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• 2013

본 연구는 오미자 추출물의 구강병원균에 대한 항균활성과 항구취 효과를 조사하기 위해 수행되었다. 오미자 MeOH 추출물이 열수추출물에 비해 구강병원균에 대한 항균활성이 더 뛰어난 것으로 나타났다. 특히 MeOH 추출물의 EA 분획물은 Streptococcus mutans, S. sanguinis, S. salivaris subsp. thermophols 그리고 Porphyromons gingivalis에 대한 활성이 뛰어난 것으로 조사되었다. 오미자 2% MeOH 추출물의 항구취 효과를 oral chroma를 이용한 실제실험에서 측정한 결과, 황화수소, 메틸머캅탄 그리고 황화디메틸을 각각 91.15, 78.72 그리고 71.58% 감소시키는 것으로 측정되었다. 본 연구 결과, 오미자 추출물은 몇몇의 구강병원균에 대한 항균활성을 보였고 휘발성 화합물을 억제하는 효과가 뛰어난 것으로 나타났다. 그러므로 오미자의 추출물은 항균용 합성약품과 구강위생용품을 대체할 수 있는 소재로 판단된다.