• 대한치과보존학회:학술대회논문집
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• 대한치과보존학회 2001년도 추계학술대회(제116회) 및 13회 Workshop 제3회 한ㆍ일 치과보존학회 공동학술대회 초록집
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• pp.586.1-586
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• 2001

Large butt-joint box typed class II cavites with cervical margins 1mm below the cemento-enamel junction were cut into 70 extracted human molars. The cavities(7 groups, n=10) were filled using a closed/open sandwich restoration or total bond restoration technique with materials according to the manufacturer's recommandation using the single-component bonding agent for each system. Teeth were thermocycled 500 times between $5^{\circ}C$ and $55^{\circ}C$ with 30-second dwell times.(omitted)

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 학술회의 논문집 정보 및 제어부문 B
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• pp.629-632
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• 2003

Piezo actuators are mainly used in precision position control system because of their high position resolution. Although there have been many approaches in open loop control of this, those method turn out to be not effective in precision control due to hysteresis and creep. To overcome the problems, closed loop PI control method is used in commercial products. However, it is very difficult to obtain fast response with conventional PI control although piezo actuator has fast response. In this paper, we propose a fuzzy PI control method with the proposed fuzzy PI controller, we obtains faster settling response over the conventional PI controller. We verify the effectiveness of the proposed method with experimental results.

• 대한한방부인과학회지
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• 제26권4호
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• pp.30-47
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• 2013

목 적: 본 연구는 만성 스트레스로 인한 갱년기 우울증 모델에서 사물탕가향부자(SGH)의 항우울 효과를 검증하여 실험적 유의성을 확인하고자 시행되었다. 방 법: 난소적출 흰쥐에 4주간 만성 스트레스를 가하고 SGH(100 and 400 mg/kg/day)를 투여한 후 행동검사인 sucrose intake test(SIT), elevated plus maze(EPM), forced swimming test(FST) 및 Morris water maze test(MWMT) 등을 통한 우울행동 변화와 혈청 corticosterone(CORT), IL-$1{\beta}$ 및 IL-4 등의 변화를 측정하였고, 또한 뇌 내 hippocampus와 hypothalamus에서 5-HT의 변화를 측정하였다. 결 과: 1. SIT에서 SGH 400 mg/kg/day 투여군은 대조군에 비해서 자당 섭취가 유의하게 증가하였다(p<0.05). 2. EPM에서 SGH 400 mg/kg/day 투여군은 대조군에 비해서 open arms에 머무는 시간이 유의하게 증가하였고(p<0.01), open arms와 closed arms를 교차하는 횟수도 대조군에 비해서 유의하게 증가하였다(p<0.05). 3. FST에서 SGH 100 mg/kg/day, 400 mg/kg/day 투여군 모두 대조군에 비해서 immobility시간이 유의하게 줄어들었다(SGH 100 p<0.05, SGH 400 p<0.01). 4. MWMT에서 SGH 100 mg/kg/day, 400 mg/kg/day 투여군은 모두 대조군에 비해서 실험 4일째에서 acquisition trials 수행 시간이 유의하게 단축되었고(p<0.05), SGH 400 mg/kg/day 투여군은 대조군에 비해서 retention trials 수행 시간이 유의하게 증가하였다(p<0.05). 5. CORT와 IL-4 측정에서 대조군과 SGH 투여군 모두 유의한 변화가 없었고, IL-$1{\beta}$ 측정에서 대조군에서는 유의하게 증가하였지만 SGH 투여군에서는 대조군에 비해서 유의한 변화가 없었다. 6. Hippocampus에서의 5-HT 측정에서 SGH 400 mg/kg/day 투여군은 대조군에 비해서 유의하게 증가하였다(p<0.05). Hypothalamus에서의 5-HT수준은 SGH 투여군 모두 대조군에 비해서 유의하게 증가하였다(SGH 100 p<0.05, SGH 400 p<0.01). 결 론: 이상의 결과로 SGH는 만성 스트레스를 가한 난소적출 흰쥐에서 항우울 효과가 있음을 알 수 있었고, HPA axis, immune system 보다 5-HT system에 작용하는 것으로 사료된다.

• 대한정형도수물리치료학회지
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• 제12권2호
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• pp.52-65
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• 2006

Sling exercises therapy can speak as appliable comprehensive exercises therapy technique efficiently in general exercise field for injured worker's rehabilitation process and health improvement patient or athlete, injury or disease that have pain or dysfunction to neuromuscular system using that shake. At 1990 an early stage, because physical therapist and doctors of medical treatment developed country norway of north europe cooperate sling exercises therapy's concept trend spreading worldwide establishing theory newly based on scientific basic be. Musculoskeletal system, old man and young child's nervous system injurer's treatment and exercise and industry worker's rehabilitation process, athlete's rehabilitation etc. several fields introduced in early 2000s to Korea apply. Sling exercises therapy neuromuscular system disease continuous abatement as general concept of active exercise and treatment that use sling exercises equipment by purpose know can. This review article wishes to introduce about neuromuscular activation, "Neurac" technique that can speak as step developed more concept based on application principle etc, of basic sling exercises effort's change by suspension point's change that is concept, stability exercises principle, open kinetic chain exercises and closed kinetic chain exercises. Arranged about Plateau potential's characteristic and working mechanism and Neurac technique's application method that can say as Neurac technique's neuro-physiologic base, and presented treatment method of lumbar part disease and cervical part, shoulder joint part disease to application example. Because plateau potential forward player that induce using Neurac technique in part muscles that act role that keep spine surrounding stability in this article keeps muscle's contraction continuously, between global and local muscles, presented several study findings that can cause affirmative change in insufficient muscle adjustment state such as imbalance of muscles' action order. Expect that case studies that use this Neurac technique here after consist continuously.

• Journal of Biosystems Engineering
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• 제10권1호
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• pp.54-68
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• 1985

It is desirable to collect the solar thermal energy at relatively high temperature in order to minimize the size of thermal storage system and to enlarge the scope of solar thermal energy utilization. So far the concentrating solar collector has been developed to collect solar thermal energy at relatively high temperature, but it has some difficulties in maintaining the volumetric body of solar collector for long term utilization. On the other hand, the flat-plate solar collector has been developed to collect the solar thermal energy at low temperature, and it has advantages in maintaining the system for long term utilization, since it's thickness is thin and not volumetric. In this study, to develop a solar collector that has both advantages of collecting solar thermal energy at high temperature and fixing conveniently the collector system for long term period, a cylindrical parabolic concentrating solar collector was designed, which has two rows of parabolic reflectors and thin thickness such as the flat-plate solar collector, maintaining the optical form of concentrating solar collector. The characteristics of the concentrating parabolic solar collector newly designed was analysed and the results are summarized as follows; 1. The temperature of the air enclosed in solar collector was all the same as $50^{\circ}C$ in both cases of the open and closed loop, and when the heat transfer fluid was not circulated in tubular absorber, the maximum surface temperature of the absorber was $118-120^{\circ}C$, this results suggested that the heat transfer fluid could be heated up to $118^{\circ}C$. 2. In case of longitudinal installation of the solar collector, the temperature difference of heat transfer fluid between inlet and outlet was $4^{\circ}-6^{\circ}C$ at the flow rate of $110-130{\ell}/hr$, and the collected solar energy per unit area of collector was $300-465W/m^2$. 3. The collected solar energy per unit area for 7 hours was 1960 Kcal/$m^2$ for the open loop and 220 Kcal/$m^2$ for the closed loop. Therefore it is necessary to combine the open and closed loop of solar collectors to improve the thermal efficiency of solar collector. 4. The thermal efficiency of the solar collector (C.P.C.S.C.) was proportional to the density of solar radiation, indicating the maximum thermal efficiency ${\eta}_{max}=58%$ with longitudinal installation and ${\eta}_{max}=45%$ with lateral installation. 5. The thermal efficiency of the solar collector (C.P.C.S.C.) was increased in accordance with the increase of flow rate of heat transfer fluid, presenting the flow rate of $110{\ell}/hr$ was the value of turning point of the increasing rate of the collector efficiency, therefore the flow rate of $110{\ell}/hr$ was considered as optimum value for the test of the solar collector (C.P.C.S.C.) performance when the heat transfer fluid is a liquid. 6. In both cases of longitudinal and lateral installation of the solar collector (C.P.C.S.C.), the thermal efficiency was decreased linearly with an increase in the value of the term ($T_m-T_a$)/Ic and the increasing rate of the thermal efficiency was not effected by the installation method of solar collector.

• 한국지하수토양환경학회지:지하수토양환경
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• 제17권6호
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• pp.23-32
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• 2012

This study was conducted to monitor microbial species dynamics within the aquifer due to long term operation of geothermal heat pump system. The species were identified by molecular biological methods of 16S rDNA. Groundwater sample was collected from both open (S region) and closed geothermal recovery system (J region) along with the control. J measured and control as well as S measured found Ralstonia pickettii as dominant species at year 2010. In contrast, Rhodoferax ferrireducens was dominantly observed for the control of S. In 2011, Sediminibacterium sp. was universely identified as the dominant species regardless of the monitoring places and type of sample, i.e., measured or control. The difference in the dynamics between the measured and the control was not critically observed, but annual variation was more strikingly found. It reveals that possible environmental changes (e.g. ORP and DO) due to the operation of geothermal heat recovery system in aquifer could be more exceedingly preceded to differentiate annual variation of microbial species rather than positional differences.

• Journal of Electrical Engineering and Technology
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• 제3권2호
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• pp.224-234
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• 2008

Multi-phase machines can be used in variable speed drives. Their applications include electric ship propulsion, 'more-electric aircraft' and traction applications, electric vehicles, and hybrid electric vehicles. Multi-phase machines enable independent control of a few numbers of machines that are connected in series in a particular manner with their supply being fed from a single voltage source inverter(VSI). The idea was first implemented for a five-phase series-connected two-motor drive system, but is now applicable to any number of phases more than or equal to five-phase. The number of series-connected machines is a function of the phase number of VSI. Theoretical and simulation studies have already been reported for number of multi-phase multi-motor drive configurations of series-connection type. Variable speed induction motor drives without mechanical speed sensors at the motor shaft have the attractions of low cost and high reliability. To replace the sensor, information concerning the rotor speed is extracted from measured stator currents and voltages at motor terminals. Open-loop estimators or closed-loop observers are used for this purpose. They differ with respect to accuracy, robustness, and sensitivity against model parameter variations. This paper analyses operation of an MRAS estimator based sensorless control of a vector controlled series-connected two-motor five-phase drive system with current control in the stationary reference frame. Results, obtained with fixed-voltage, fixed-frequency supply, and hysteresis current control are presented for various operating conditions on the basis of simulation results. The purpose of this paper is to report the first ever simulation results on a sensorless control of a five-phase two-motor series-connected drive system. The operating principle is given followed by a description of the sensorless technique.

• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제9권3호
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• pp.109-122
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• 2020

최근 실감 미디어 콘텐츠에서 높은 관심을 모으고 있는 프로젝션 맵핑은 사용자의 몰입감을 높이는 기술로 손꼽히고 있다. 최근 관객의 참여를 유도하기 위하여 제스처 인식 기술과 결합된 프로젝션 맵핑 콘텐츠들이 선보이고 있다. 그러나 대부분의 기존 방법들은 정적인 물체를 대상으로 프로젝션 맵핑을 수행하고 있다. 이에 본 논문에서는 사용자의 움직임을 추적하여 사용자의 신체상에 미디어 콘텐츠를 동적으로 프로젝션 맵핑시키는 기술을 개발하였다. 프로젝션 되는 미디어 콘텐츠는 미리 정의된 사용자의 제스처를 인식하여 사용자가 맨손으로 제작할 수 있도록 하였다. 이러한 동적 프로젝션 맵핑 기술과 제스처 기반 드로잉 기술을 통합하여 인터랙티브한 실감미디어 시스템을 구현하였다. 제안된 실감 미디어 시스템에서는 사용자의 양손의 움직임과 개폐 상태를 인식하여 그림을 그리는데 필요한 기능을 선택하고, 임의의 물체 색상을 붓의 색으로 설정하는 등의 기능을 통해 자유롭게 그림을 그릴 수 있게 해준다. 또한 사용자가 그린 그림을 사용자의 몸에 동적으로 투사해 사용자가 실시간으로 자신의 티셔츠를 디자인하고 이를 착용해 보는 효과를 가질 수 있도록 하였다.

• 한국산업보건학회지
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• 제17권3호
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• pp.254-260
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• 2007

Trichloroethylene(TCE) is widely used as a degreasing solvent in workplaces. TCE is primarily toxic to the nervous system, however, systemic disorder like Stevens-Johnson syndrome has been recently reported in small-scale factories, where the government has had limited information of chemical use. A survey was performed to investigate the actual condition of using TCE and to provide practical information to occupational health service agencies and professionals. This survey was carried out on 103 factories out of 430 factories which were conducted periodic work environment measurement for TCE. Degreasing was the most popular reason for using TCE in Korea, which reached to 94%. TCE was also used as a solvent for rubber in the coating or molding process, and adhesives in the bonding process. Metal fabrication was the most common as 23%, followed by assembling automobile parts (17%), and machinery (12%). Workers exposed to TCE during full-shift were 52% while 48% were exposed during short period of the shift or intermittently. Manual or semi-automatic work occupied 87% while automatic work was just 13%. Though automatic work by a closed system was generally lower exposed to TCE, compared to manual work, it can cause a high exposure when the maintenance system is improper. Semi-automatic work especially like open-top degreasing process can cause a high exposure when local exhaust system with condensing and refrigerating coils in the degreaser does not work well. In conclusion, the survey showed nationwide status of TCE exposure in various aspects. It can be used to monitor workplaces and workers exposed to TCE to prevent occupational diseases.

• 한국추진공학회지
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• 제24권5호
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• pp.21-33
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• 2020

본 연구에서는 액체 수소를 연료로 사용하는 팽창기 사이클 로켓 엔진의 시스템 해석을 위한 프로그램을 개발하였다. 수소의 물성치는 온도에 따른 이성질체의 비율을 고려하였다. 팽창기 사이클 엔진의 개방형과 폐쇄형 형식에 따른 해석 절차를 수립하고 부품별 해석 방법을 제시하였다. 본 해석 프로그램의 검증을 위해 팽창기 사이클 엔진인 Vinci와 SE-21D를 대상으로 엔진 작동점의 성능 및 국외에서 수행된 해석 결과와 비교하였다. 해석 결과, 입력 정보가 부정확한 일부를 제외한 추진제의 질유량, 비추력, 동력과 같은 시스템의 주요 성능 인자는 1~2% 내외의 오차로 높은 정확도를 나타내었다.