• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.369-377
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• 2013

This paper deals with the state of charge(SOC) and life cycle evaluation algorithm for lead-acid battery, which is essential factor of the electric vehicle(EV) and the stabilization of renewable energy in the smart grid. In order to perform the effective operation of the lead-acid battery, SOC and life cycle evaluation algorithm is required. Specific gravity with the change of electrolyte temperature inside battery case should be obtained to evaluate the SOC of lead-acid battery, however it is difficult to measure the electrolyte temperature of sealed type lead-acid battery. To overcome this problem, this paper proposes the equation of thermal transmission to compensate internal temperature of the lead-acid battery. Also, it is difficult to exactly evaluate the life cycle of battery, depending on the operation conditions of lead-acid battery such as charging and discharging state, self discharging rate and environmental issue. In order to solve the problem, this paper presents the concept for gravity accumulation of charge and discharge cycle, which is the value converted at $20^{\circ}C$. By using the proposed algorithm, this paper propose the test device based on the Labview software. The simulation results show that it is a practical tool for the maintenance of lead-acid battery in the field of industry.

• Applied Chemistry for Engineering
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• v.7 no.3
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• pp.588-596
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• 1996

The optimum conditions of the 1st and 2nd distillation had been investigated to obtaine a high quality monomeric MDI and fire reactive polymeric MDI by purification of crude MDI. Effect of additives on the monomeric MDI's color change, dimerization and the reactivity of polymeric MDI with standard polyol system has been tested. When the monomeric MDI yield is approximately 32%, 4,4'-MDI content is above 98% in the monomeric MDI at the 1st distillation. When the separation ratio of initial portion and residue percentage, reflux ratio are set at respectively, approximately 20wt%, 9wt%, above 2 in order to minimize the content of 2,4'-MDI in monomeric MDI, the freezing point of final distilled monomeric MDI is above $38.4^{\circ}C$. Since the monomeric MDI is inherently unstable in the room condition, monomeric MDI easily changes it's color and conducts self-polymerization reaction. To increase the stability of monomeric MDI, the composition of antioxidant, which is composed of phenolic 1st antioxidant, phosphorus 2nd antioxidant, UV absorbent and Hindered amine light stabilizer are used, and benzoyl chloride as antipolymerization agent test are that APHA color is less than 20, dimer content is remained less than 0.36wt% after 45 days storage of monomeric MDI.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1942_1943
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• 2009

무선통신 시스템의 소형화와 저가격, 고품질, 다기능 재료 및 첨단 가공 기술과 연계된 필터설계 및 제작 기술에 대한 연구가 활발히 진행 중이다. 그러나 무선통신 시스템은 주파수라는 한정된 자원을 사용하기 때문에 주파수 자원의 효율적 관리를 위한 규제나 방안이 필요하고. 이에 따라서 여러 가지 대책과 방안이 필요로 하고 있다. 그래서 필터의 성능개선을 위한 연구가 본질 적으로 중요하게 되었다. 본 논문은 체비세프(Chebyshev)필터와 버터워스(Butterworth)필터를 이용한 대역통과(band pass) 필터를 제안한다. 이 필터는 안정화된 통과대역과 빠른 주파수 응답을 얻기위해 6차 체비세프필터와 8차 버터워스필터를 결합 하였다. 측정된 대역통과 필터는, 차단 영역을 구분하는 스커트(skirt)특성은 날카롭게(sharp) 되었고 통과대역의 평탄도 또한 개선되어짐을 볼 수 있다. 제안된 필터의 중심주파수는 2.5GHz, 대역폭은 200MHz이고, 대역내 평탄도는 0.5dB, 경사도는 오차가 60dB일때 체비세프는 210MHz, 버터워스는 340MHz, 체비세프-버터워스는 290MHz가 되어 버터워스 보다 좋게 되었으며 극점의 배치도 안정적인 결과를 얻었다.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.115-132
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• 2012

The purpose of this study is to examine the current status of user-contributed reviews for the Next Generation Library Catalogs, and the potential impact of user reviews available from the external sources, including Amazon.com and GoodReads.com. During the period of February 16th through April 4th, 2012, the number of holding libraries and user-contributed reviews, tags and reading lists of ten selected books were examined from the WorldCat. Also the user-contributed reviews for the same books available from Amazon.com and GoodReads.com were examined, and a case of reviews for one book was analyzed. The result shows that only a few users participated in the WorldCat, and user-contributed reviews were rarely used, when compared with tags or reading lists. Several hundred to thousand user-contributed reviews for the same books were available from Amazon.com and GoodReads.com directly linked with bibliographic records. A case of one book from Amazon.com reveals the possibility of distorting the function of user-contribution. With the introduction of the function of user-contribution, it is expected that its growth rate should be carefully observed and its potential impact on users should be thoroughly and systematically analyzed in the near future.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.9 no.4
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• pp.301-308
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• 2015

The purpose of this study was to compare core muscle activity and thickness in the abdomen (internal Oblique, IO; External Oblique, EO; Transverse Abdominis, TrA) according to walking training methods. Tests were performed on 20 healthy men who randomly assigned to two groups, divided by Nordic walking (n=10) or Power walking group (n=10). They were performed Nordic walking or Power walking training for 2 weeks that is consistent with each of the assigned groups. Results demonstrated that Nordic walking was more effective than Power walking in improving IO and EO activities. Nordic walking is believed to be useful method for a variety of therapeutic exercise as a stable balance with the stick in addition to normal gait and trunk stability.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.1960_1961
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• 2009

본 논문에서는 PID, PWM, HSC, 컴퓨터와의 호스트 통신, 외부 DAC 인터페이스를 FPGA만을 이용하여 하나의 Chip에 구현하고 DC 서보 모터의 속도를 설정한 제어 상태로 안정화시킬 수 있는 시스템을 구현하고자 한다. 컴퓨터에서 설정한 설정치(SV)와 P, I, D의 이득 값을 호스트 통신으로 데이터 블록은 해당 블록으로 전달하며 DC 서보 모터의 엔코더에서 나오는 $90^{\circ}$ 위상차가 있는 2채널의 펄스는 HSC 블록을 거쳐 프로세스치(PV)를 생성 고 이로부터 얻어진 SV와 PV의 편차(E)를 산출한 후 PID 제어 동작을 수행한다. 그 결과인 조작치(MV)를 PWM 블록에 제공하여 실질적으로 DC 서보 모터를 구동하는 H-bridge 회로를 구동한다. 또한 FPGA 내부의 SV, PV, E, MV를 오실로스코프로 계측하기 위해 DAC 인터페이스 블록을 첨가 하여 외부 디지털 아날로그 변환기(DAC)를 제어 하였다.

• 한국연소학회:학술대회논문집
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• 2007.05a
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• pp.133-138
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• 2007

Influence of changing combustor pressure on flame stabilization and emission index in the swirl-stabilized flame was investigated The combustor pressure was controlled by suction fan at combustor exit. Pressure index ($P^{\ast}=P_{abs}/P_{atm}$), where $P_{abs}$ and $P_{atm}$ indicated the absolute pressure and atmosphere pressure, respectively, was controlled in the range of $0.7{\sim}1.3$ for each equivalence ratio conditions. The flammable limits of swirl flames were largely influenced by changing combustor pressure and they showed similar tendency with laminar flames. $NO_x$ emission index decreased with decreasing pressure index for overall equivalence ratio conditions. R.m.s. of pressure fluctuations is increased with decreasing combustor pressure. This flame fluctuation caused incomplete combustion , hence CO emission index increased. These oscillating flames were measured by simultaneous $CH{\ast}$ chemiluminescence time-series visualization and pressure fluctuation measurement.

• Electronics and Telecommunications Trends
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• v.19 no.2 s.86
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• pp.9-17
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• 2004

지속적인 경제성장을 위한 기술정책방향은 다음과 같은 두 가지 경제적 환경변화를 고려해야 한다. 첫째, 신기술을 중심으로 하는 새로운 차세대성장산업을 창조함으로써, 지속적으로 우리나라 경제성장을 견인하는 “신기술중심의 경제성장정책기조”이다. 둘째, 신무역질서에서 우리나라 경제를 안정화시켜야 하는 정책기조와, 더 나아가 세계경제발전에 기여하는 “세계경제질서에서 대한민국경제위상확보정책기조”이다. 본 논고에서는 신기술발전과 신무역질서라는 연관관계에서 어떤 신성장 기술정책방향이 바람직한 것인지 알아보자. 이 연관분석을 위하여 우리나라 주요 교역국가를 중심으로 우리나라 신기술발전이 다른 무역대상국가에 어떤 경제적 영향을 미치며, 다른 주요 교역국가인 미국과 일본의 기술발전이 우리나라에 어떤 경제적 영향을 미치는지를 정량적으로 분석하였다. 본 연구결과를 바탕으로 간단한 국제무역환경을 고려한 기술정책방향에 대하여 제언하였다.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.693-697
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• 2005

We researched in the optimization of unit process and the stabilization of discharged water quality through the treatment of the occurrence of wastewater classified by place of production which has high COD load and non degradable COD load in paper industry. As the result, using polymer, inorganic flocculants and alum at the same time is effective to advance the COD value through the colloid material removal with SS in the first treatment process. Moreover, it is determined to keep optimum of $FeCl_2/H_2O_2$ in the concentration of 1000 ppm in the ratio of 1/1. Because It is confirmed that to input excess chemicals using Fenton oxidation method gives adverse effect to water quality.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.49 no.2
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• pp.97-106
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• 2023

In this study, we would like to study the stabilization of the high content of ceramide formulation by containing cyclodextrin. Ceramide, which constitutes the intercellular lipid, a human skin barrier, is a very important ingredient in moisturizing maintenance by protecting moisture in the skin and strengthening the skin barrier. However, since ceramide is poorly soluble, even if it is included in the cosmetic formulation, it has a problem that it is slowly gelled or crystallized and deposited over time, making it difficult to containing a high amount of ceramide. Cyclodextrin is a cyclic oligosaccharide connected with glucose molecules and has a cylindrical structure with hydrophilic outer surface and hydrophobic inner surface, which is known to improve the physicochemical properties of drugs such as improving solubility and absorption of poorly soluble drugs. We demonstrated the stability of the formulation containing high amount of ceramide by measuring hardness and observing emulsion drops with polarized microscope. This study also demonstrated that the high-content ceramide formulation containing cyclodextrin has the effect of preventing gelation or crystallization of ceramide, thus having excellent environmental conditions stability and skin moisturization.