• Proceedings of the SAREK Conference
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• 2007.11a
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• pp.82-87
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• 2007

In the present study, the simulation on the annual performance evaluation of a renewable energy systems with fuel cell driven compound source hybrid heat pump systems is applied to the heating and cooling of large community building. The large community building has the economical advantage to apply heat pump cooling and heating systems the long period operation. If air and ground source hybrid heat pump systems are combined, COP of the system can be increased largely. Fuel cell driven compound source hybrid heat pump system can reduced the fuel cost as well as thermal storage tank sharply.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.04a
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• pp.56-59
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• 2012

최근 신재생 에너지 분야 가운데 풍력발전에 대한 관심이 높아지면서 관련 산업 분야의 연구 또한 활발히 수행되고 있다. 풍력발전기의 경우 초기 설치에 고가의 비용이 필요하며, 고장 발생 시 일반적으로 풍력발전기의 동작을 멈추게 한다. 본 논문에서는 풍력발전기의 Nacelle에서 발생하는 다양한 센서데이터를 수집하는 Bottom에서의 제어시스템을 다중화하여 고장 발생 시에도 풍력발전기의 중단 없이 지속적으로 에너지 생산이 가능하게 하는 고가용성 데이터베이스 시스템에 관한 것이다. 본 논문을 통해 개발된 고가용성 시스템을 통해 풍력 발전기의 높은 안정성을 보장하며, 수집된 데이터를 분석함으로서 고장에 대한 예측이 가능하다.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.43 no.9 s.351
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• pp.105-119
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• 2006

The car navigation system to be accompanied to the car on-board equipment system or the development of mobile communication technique, the demand in information communication which connects an interior and the car outside is coming to be high, As applications, ETC/VISC/AHS classes get deceived supply are advanced. The research of DSRC radio systems actively, with medium of communication between the automobile and road, is advanced. DSRC radio systems are appropriate in massive data transfer, in the case which the traffic accident evasion is urgent, the notarization of the preferential control function which is necessary to a medium of communication, guarantee and security are suitable in the high-speed network. Accompanied to the cellular phone which is to be supplied recently suddenly, By complementing and coexisting each other, and it will be developed simultaneously. However, in a connection of this kind of communication system and high-speed DSRC radio system, Hand-over technique (network, radio transmission hand-over), there is a technical subject of the high-speed transmission techniques against the mobile devices and the realization is expected to be difficult in near, until 2010 year is becoming the plan of putting to practical use. Also as the next generation DSRC with 5.8GHz built-on board equipment and the road-side equipment are expected in near. In this paper DSRC systems which will be developed are discussed.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.4
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• pp.738-745
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• 2001

In this paper, when the moving object move to the three-dimentional space, the tracking system track the moving object using the fuzzy reasoning. The joint angle el of the manipulator rotate from $0^{\circ}\; to\; 360^{\circ}$ , and the joint angle $\theta_2$rotate from$0^{\circ}\; to\; 360^{\circ}$. The fuzzy singleton is used for fuzzification and the control rule is twenty five and the fuzzy inference method is simplified Mamdani's reasoning and the defuzzification is the SCOG(Simplified Center Of Gravity) of the fuzzy controller To measure of the performance of the designed system, the fuzzy controller is compared with the CTM(Computed Torque Method) controller at the same condition. when the disturbance torque is ON, the both of CTM and fuzzy controller tracked object without error, However, the disturbance torque changed 0.4N, the CTM controller is 10 times greater than fuzzy controller at the sum of absolute error difference. The designed system is showed it's robustness against with disturbance.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.6
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• pp.625-632
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• 2012

The objective of this paper is to demonstrate the cathode channel flooding effects at different stoichiometries in proton exchange membrane (PEM) fuel cells by using visualization techniques. The phenomena of liquid water formation and removal caused by current variations were also examined experimentally. Tests were conducted at cathode stoichiometries of 1.5 and 2.0, and the anode stoichiometry was fixed at 1.5. It is found that at an air-side stoichiometry of 2.0, liquid water begins to form and the flooding occurs faster than at an air-side stoichiometry of 1.5. Also, when the air-side stoichiometry of 1.5 is maintained, the dry-out phenomena is observed in the dry-out area 7.8 A following the field of flooding. Thus, a stoichiometry of 1.5 produced better performance in terms of membrane electrode assembly (MEA) durability and hydrogen ion conductivity than did a stoichiometry of 2.0, in which dry-out occurs beyond 8A.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.12
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• pp.1113-1122
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• 2009

In order to find the way to solve the problem of sewage sludge discharge into the ocean, the sludge solubilization by ultrasonic and the improvement methods of wastewater treatment process were studied. In the membrane bioreactor the sludge retention time was stepwise increased from 5.1 day to 442 days where the biomass average concentration has been increased from $c_B$=3.4 $gTSSL^{-1}$ to $c_B$=14.5 $gTSSL^{-1}$ respectively. At the same time, the biomass yield coefficients were reduced from 0.5-0.7 at SRT=5.1 day to 0.005-0.007 at SRT=442 days which means the reduction of sludge production. Oxygen mass transfer coefficients and ${\alpha}$-factor were investigated with changing stirrer speed to find the relation between the high biomass concentration and aeration efficiency in the propeller loop reactor. As a result of sludge solubilization, the solubilization of sludge by ultrasound was increased with increasing energy input and it led to improved anaerobic digestion rate with more biogas production than that of nonsolubilized sewage sludge.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.634-637
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• 2008

Ground source heat pumps are clean, energy-efficient and environment-friendly systems cooling and heating. Although the initial cost of ground source heat pump system is higher than that of air source heat pump, it is now widely accepted as an economical system since the installation cost can be returned within an short period of time due to its high efficiency. In the present study, performances of ground source compound hybrid heat pump system applied to a large community building are simulated. The system design and operation process appropriate for the surrounding circumstance guarantee the high benefit of the heat pump system applied to a large community building. If among several renewable energy sources, ground, river, sea, waste water source are chosen as available alternative energies are combined, COP of the system can be increased largely and hybrid heat pump system can reduced the fuel cost.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.21 no.6
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• pp.355-366
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• 2009

In the present study, fuel cell driven ground source heat pump system is applied to a large community building and performance of the heat pump system is computationally analyzed. Conduction heat transfer between brine pipe and ground is analyzed by TEACH code to predict the performance of heat pump system. Predicted COP of the heat pump system and the energy cost were compared with variation of the location of the objective building the water saturation rate of soil and the driven powers of heat pump system. Significant reduction of energy cost can be accomplished by employing the fuel cell driven heat pump system in comparison with the late-night electricity driven system. It is due to the low electricity production cost of fuel cell system and the application of recovered waste heat generated during electricity production process to the heating of large community building.

• YAKHAK HOEJI
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• v.51 no.1
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• pp.51-55
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• 2007

Among pteridophytes, Selaginella involvens Spring and Equisetum orvense L. are used in folk medicine in Eastern Asian countries including Korea. The water extracts from Selaginella involvens spring (SW) and from Equistum arvense L (EW) did not affect viability of human umbilical vein endothelial cells (HUVECs). However, SW dose-dependently inhibited tube formation and migration of HUVECs, whereas EW did not. These results suggest that the water extract from Selaginella involvens Spring may have anti-angiogenic activity.

• Proceedings of the Korea Information Processing Society Conference
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• 2011.04a
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• pp.3-6
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• 2011

IT 기술의 발전에 따른 전력 사용량 증가로 인해서 친환경 재생 에너지에 대한 관심이 집중되고 있는 상황으로 다양한 재생 에너지자원 가운데 풍력에너지 개발이 전 세계적으로 급속히 증가하고 있다. 그러나 풍력발전기를 제어하는 제어기의 소프트웨어·하드웨어적인 문제로 인해 불규칙한 에너지 생산과 유지보수를 위한 비용이 증가함에 따라 최근에는 풍력제어기의 고장분석 및 고장 감내 제어에 대한 연구가 활발히 진행되고 있는 상황이다. 본 논문에서는 이와 같은 풍력발전기가 지속적으로 일정한 에너지 생산과 유지보수 절감이 가능하도록 하기 위해 풍력제어시스템 차원에서의 고장에 대해서 감내 가능한 고가용성의 미들웨어에 대한 구조를 제안한다. 풍력제어시스템의 고 가용성 미들웨어는 가상 운영체제를 기반으로 이중화 구조를 가지고 있으며, 주 운영체제에서 소프트웨어적인 고장이 발생 시 다음 우선순위의 가상 운영체제에서 지속적인 서비스를 제공할 수 있도록 각각의 가상 운영체제 환경을 관리한다.