• Proceedings of the Korean Society of Precision Engineering Conference
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• 2009.06a
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• pp.917-918
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• 2009

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.11a
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• pp.761-762
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• 2010

• Proceedings of the KIEE Conference
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• 1997.07f
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• pp.2177-2180
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• 1997

The solar cell has an optimum operating point to be able to got maximum power. To obtain maximum power from Photovoltaic array, hotovoltaic power system usually requres maximum power point c tracking controller. The output characteristics of solar cell are nonlinear, and these characteristics vary with load solar insolation, solar cell temperature. Therefore the tracking control of maximum power point is the com-plicated problem. This paper presents power characteristics of residential Photovoltaic system applying a buck-boost conversion system.

• Proceedings of the KIEE Conference
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• 1991.07a
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• pp.482-485
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• 1991

This paper discusses a maximum power point tracking controller (MPPTC) by using chopper with an adjustable input to output voltage. The MPPTC is determined by sensing only the actual voltage from solar cell array. It is simple and continuously tracks the solar cell array maximum power point regardless of the load type. Also, the system obtains protection circuit to protect overcharge and disovercharge against the battery.

• Journal of Biosystems Engineering
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• v.32 no.5
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• pp.284-291
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• 2007

This study was to investigate performance of position, basic controls and additional control for man-machine interface on a 3-point hitch of a tractor. The developed additional control was one-touchup, backup, turnup, liftarm limited, PTO on/off and an external control. As a result of experiment, maximum steady state error of response system was lower than $0.8^{\circ}$ and this result showed the function operated normally because the dead band of system set was ${\pm}1^{\circ}$. There was no abnormal situation by switch operation and sensor signal during the performance test. The results of experiment showed the characteristics of the response was sufficient to be used as the position and additional control system for tractors.

• Bulletin of the Korean Mathematical Society
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• v.46 no.2
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• pp.311-319
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• 2009

Let H be a Hilbert space which is the direct sum of five closed subspaces $X_0,\;X_1,\;X_2,\;X_3$ and $X_4$ with $X_1,\;X_2,\;X_3$ of finite dimension. Let J be a $C^{1,1}$ functional defined on H with J(0) = 0. We show the existence of at least four nontrivial critical points when the sublevels of J (the torus with three holes and sphere) link and the functional J satisfies sup-inf variational inequality on the linking subspaces, and the functional J satisfies $(P.S.)^*_c$ condition and $f|X_0{\otimes}X_4$ has no critical point with level c. For the proof of main theorem we use the nonsmooth version of the classical deformation lemma and the limit relative category theory.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.187-189
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• 2006

Compensators need to keep the voltage properly at the KEPCO system in a ruddle-long term point of view. Therefore, it is necessary to forecast the amount of compensators. In this paper, we analyze how much compensators are needed and what kind of effects is given on the KEPCO system in a middle-long term point of view. In addition, this analysis is based on the books named "The plan of Transmission and Substation at the KEPCO in 2005" and we used PSS/E program when we analyze the KEPCO system.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07b
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• pp.1536-1537
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• 2005

We have made point electron sources using carbon nanotubes (CNTs). For the fabrication of point electron sources, CNTs were dispersed in a solution and attached on electrochemically etched W tips using electrophoresis. In our study, we have utilized various CNTs such as single-walled CNT (SWCNT), multiwalled CNT (MWCNT), and thin-MWCNT and threshold current, turn-on voltage, filed enhancement factor of each emitter have been studied upon a tube/bundle diameter and length. In addition, fieldemitted electron energy distribution of various CNT emitters is characterized.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.227-228
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• 2006

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.909-914
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• 2001

After burner which is main part of inert gas generator(IGG) is studied for the development of IGG. The results of many experimental equations are applied to estimate characteristics of the spray nozzle and evaporation of spray, and selected the optimum design point of after burner. The selected design point of after burner are validated experimentally through the pilot plant of after burner. The flame stability is favorable at design point(150mm), that distance from stabilizer to nozzle. The emission of $NO_x$ and CO is lower than gas turbine combustor which was used in primary combustor.