• 한국약용작물학회지
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• 제24권4호
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• pp.277-283
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• 2016

Background: The photosynthetic efficiency cool-season, semi-shade ginseng is normal at low morning temperatures, but drops at high afternoon temperatures. Therefore, optimal plant performance would be ensured if it were possible to control daily light transmission rates (LTR). Methods and Results: Plants were grown in a controlled light environment that replicated 11 AM conditions and comparatively analyzed against plant grown under normal conditions. Growth in the controlled light environment resulted in a 2.81 fold increase in photosynthetic efficiency with no change in chlorophyll content, although LTR were high due to low morning temperatures. Increased aerial plant growth was observed in the ginseng plants adapted to the controlled light environment, which in turn influenced root weight. An 81% increase in fresh root weight (33.3 g per plant on average) was observed in 4-year-old ginseng plants grown in controlled light environment compared to the plants grown following conventional practices (18.4 g per plant on average). With regard to the inorganic composition of leaves of 4-year-old ginseng plants grown in controlled light environment, an increased in Fe content was observed, while Mn and Zn content decreased, and total ginsenoside content of roots increased 2.37 fold. Conclusions: Growth of ginseng under a favorable light environment, such as the condition which exist naturally at 11 AM and are suitable for the plant's photosynthetic activity creates the possibility of large scale production, excellent-quality ginseng.

• 대한전기학회논문지:시스템및제어부문D
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• 제53권9호
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• pp.644-649
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• 2004

To control a greenhouse is to control environmental parameters in greenhouse. Controlled environments may be as simple as saran-covered shade houses or as complex as growth chambers. Although greenhouses are probably the most common example of a controlled environment used in agricultural/horticultural production, the type of controlled environment or system that is needed depends upon the climate, time of year, crops being produced and the environmental parameters that must be controlled. In this contribution puts emphasis on construction of automatic-controlled greenhouse system by personal computer.

• 정보관리연구
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• 제26권2호
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• pp.61-79
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• 1995

정보검색의 성공여부는 적절한 검색어의 선정에 달려있다고 해도 과언이 아니다. 특히 CD-ROM이나 온라인목록시스템에서 주제검색시 분류표, 주제명과 같은 통제어와 자연어 등 비통제어의 비교 우위 문제는 아직도 논란이 되고 있다. 본고는 두 시스템의 검색효율성을 비교하기 위하여 특히 다언어 환경하에서의 검색어 사용에 중점을 두고 다양한 형태의 검색어휘를 조사 분석하였다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권6호
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• pp.456-459
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• 2000

A pilot scale experiment was performed for a year to develop a two-phase anaerobic process for piggery wastewater treatment (COD: 6,000mg/L, BOD: 4,000mg/L, SS: 500mg/L, pH 8.4, alkalinity 6,000mg/L). The acidogenic reactor had a total volume of 3㎥, and the methanogenic reactor, an anaerobic up-flow sludge filter, combining a filter and a sludge bed, was also of total volume 3㎥(1.5㎥ of upper packing material). Temperatures of the acidogenic and methanogenic reactors kept at 20$^{\circ}C$ and 35$^{\circ}C$, respectively. When the pH of the acidogenic reactor was controlled at 6.0-7.0 with HCl, the COD removal efficiency increased from 50 to 80% over a period of six months, and as a result, the COD of the final effluent fell in the range of 1,000-1,500 mg/L. BOD removal efficiency over the same period was above 90%, and 300 to 400 mg/L was maintained in the final effluent. The average SS in the final effluent was 270 mg/L. The methane production was 0.32㎥ CH$_4$/kg COD(sub)removed and methane content of the methanogenic reactor was high value at 80-90%. When the pH of the acidogenic reactor was not controlled over the final two months, the pH reached 8.2 and acid conversion decreased compared with that of pH controlled, while COD removal was similar to the pH controlled operation. Without pH control, the methane content in the gas from methanogenic reactor improved to 90%, compared to 80% with pH control.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2002년도 추계종합학술대회
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• pp.457-461
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• 2002

위해환경에서 동작되는 화상로봇에 대한 개발에 관하여 서술하였다. 개발된 로봇은 크게 로봇 제어부와 Host PC 에서의 Visual I/F program으로 구성되어 있다 개발된 로봇의 구동부와 Camera의 구동부는 2자유도를 갖고 있으며 유저 친화적으로 개발된 Joystick으로 원격조종된다. 외부 상황은 비젼 시스템과 초음파 센서로 인식되며, 화상 및 센서 데이터, 명령어 등을 각각 900MHz와 447MHz RF로 통신된다. 개발된 시스템의 효율성을 100m범위의 야외 시험장에서 운용되어 검사되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2688-2690
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• 1999

This paper presents the modeling method of $3{\Phi}$ phase-controlled rectifier considering the overlap interval for the drive of DC motor in the Matlab environment. The model is constructed by the module-based method and therefore it is appropriate in the research of the closed-loop controlled power electronic system in the Matlab/Simulink environment. The model of SCR is used as the element for the power transformation. The simulation results show that the overlap interval from the effect of the input inductance is accurate.

• 조명전기설비학회논문지
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• 제14권3호
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• pp.15-21
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• 2000

본 논문에서는 MATLAB/SIMULINKK를 이용한 DC 전동기 구동용 3상 워상제어 정류기 시스템의 모델링 기법을 제안하였다. 이 기법은 회로 시뮬레이터의 장점을 시스템 시뮬레이터에 도입한 것으로써 수식적인 전개가 필요없어 새로운 시스템과의 결합야 간단하다. 제안된 시스템의 전체 모델은 3상 위상제어 정류기와 DC 전동기, 속도/전류 제어기 블록으로 구성된다. 이와 같이 MATLAB/SIMULINKK 환경에서 정류기와 전동기, 제어기시스템을 통합하여 구성하고 이를 시뮬레이션한 결과, 시스템의 각부 파형이 실제 시스템과 거의 일치하고 제어기의 경우도 제어가 원활히 수행됨을 얄 수 있었다. 따라서 이 방식은 폐루프 제어되는 전력전자 시스템의 특성해석 분야에 적합하다는 것을 알 수 있다.

• 로봇학회논문지
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• 제16권2호
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• pp.147-154
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• 2021

One of the most challenging issues when robots interact with the environment is to establish contact quickly and avoid high impact force at the same time. The proposed method implements the passive suspension system using the redundancy of the torque-controlled robot. Instead of utilizing the actual mechanical compliance, the distal joints near the end-effector are controlled to act as a virtual spring-damper system with low feedback gains. The proximal joints are precisely controlled to push the mid-link, which is defined as the boundary link between the proximal and distal joints, towards the environment with high feedback gains. Compared to the active compliance methods, the contact force measurements or estimates are not required for contact establishment and the control time delay problems do not occur correspondingly. The proposed method was applied to the landing foot control of the 12-DoF biped robot DYROS-RED in the simulations. In the results, the impact force during landing was significantly reduced at the same collision speed.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 한국자동제어학술회의논문집(국내학술편); 포항공과대학교, 포항; 24-26 Oct. 1996
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• pp.636-639
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• 1996

We have developed a part of hydraulic stroke sensing cylinder using magnetic sensor that can detect each position under severe construction fields. In this paper, for evaluating the developed cylinder under various environment condition, thermal control systems and two hydraulic systems to be coupled consist of. The former is composed of an heater case, temperature sensor, and interface circuits which include SCR(silicon controlled rectifier) for the control of the voltage's phase. The latter is composed of an hydraulic cylinder for position control with solenoid valve (ON/OFF motion) and a load cylinder with proportional reducing valve. To obtain the various performance evaluation, it is carried out under high temperature condition in thermal system controlled by using Ziegler-Nichols PID tuning method and artificial disturbances such as impulse or constant force. The results show that the developed cylinder has good performance under the various environment condition.

• Tribology and Lubricants
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• 제11권5호
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• pp.66-70
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• 1995

In this investigation, a controlled-environment tribological test device has been used to study the friction coefficients of several grades of commercially-available coated and uncoated cemented carbide cutting tools in a dry air environment at different environmental chamber pressures. Tests were run in the block-on-ring configuration. The results suggest that the friction coefficient is sensitive to the level of air present, with a noticeable rise in friction coefficient with decreasing pressure or increasing vacuum level. The uncoated cemented carbide sufaces resulted in the highest friction values, whereas the coated grades yielded somewhat lower values even after the coating was removed. The results suggest the importance of friction control in the design of coatings for metal removal processes.