• Proceedings of the Korea Water Resources Association Conference
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• 1999.05a
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• pp.93-98
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• 1999

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1996.06c
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• pp.648-657
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• 1996

Autonomous speedsprayer operation in an orchard was conducted using a fuzzy logic controller (FLC). Orchard image analysis and signals of ultrasonic sensors were processed in real time. The speedsprayer was modified to be steered by two hydraulic cylinders. The FLC has two inputs of direction of running and distance from obstacles. Operation time of the hydraulic cylinders were inferred as output of the FLC. Field test results showed that the speedsprayer could be autonomously operated by the FLC along with the image processing and the ultrasonic sensors. The ultrasonic sensors didn't contribute to the improvement of guidance performance, but the speedsprayer could avoid trees or obstacles in emergent situations with them.

• Journal of Mechanical Science and Technology
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• v.15 no.5
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• pp.671-680
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• 2001

Boundary condition is one of the major factors to influence the numerical stability and solution accuracy in numerical analysis. One of the most important physical boundary conditions in the flowfield analysis is the wall boundary condition imposed on the body surface. To solve a two-dimensional Euler equation, totally four numerical wall boundary conditions should be prescribed. Two of them are supplied by the flow tangency condition. The other two conditions, therefore, should be prepared additionally in a suitable way. In this paper, four different sets of wall boundary conditions are proposed and then applied to solve high-speed flowfields around a quarter circle geometry. A two-dimensional compressible Euler solver is prepared based on the finite volume method. This solver hires three different upwind schemes; Steger-Warmings flux vector splitting, Roes flux difference splitting, and Lious advection upstream splitting method. It is found that the way to specify the additional numerical wall boundary conditions strongly affects the overall stability and accuracy of the upwind schemes in high-speed flow calculation. The optimal wall boundary conditions should be also chosen very carefully depending on the numerical schemes used to solve the problem.

• Journal of Biosystems Engineering
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• v.28 no.2
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• pp.137-142
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• 2003

The water conditioning experiments of brown rice were performed to analyze the variation of the milled rice recovery using a continuous type conditioner at Jin-ju, Yeo-ju, and Yong-in RPC(Rice Processing Complex). About 8,000 kgf, 6,000 kgf and 10,000 kgf of the brown rice of 13-14 %(wb) initial moisture contents were used as experimental materials at Jin-ju, Yeo-ju, and Yong-in respectively. The broken rice and rice bran were collected and weighted to calculate the milled rice recovery. The amounts of broken rice with water conditioned occurred lower than that of broken rice without water conditioned. And the milled rice recovery of water conditioned ones were increased as 1.22%, 0.87%, and 1.00% compared with those of the non water conditioned ones at Jin-ju, Yeo-ju. and Yong-in respectively. Especially, the result of the experiments of Jin-ju RPC showed that about 33% and 35% of total increased milled rice recovery were the portion of the moisture content increment and the broken rice reduction respectively.

• 제어로봇시스템학회:학술대회논문집
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• 2003.10a
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• pp.909-914
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• 2003

• Magazine of the Korea Concrete Institute
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• v.10 no.2
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• pp.9-19
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• 1998

• Journal of the Korean Statistical Society
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• v.6 no.1
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• pp.21-24
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• 1977

The cumulants of the sample variance are obtained in terms of the population cumulants using ALMAP (Algebraic Manipulation Package) and these results extend those of Fisher who gave the first six cumulants of the sample variance.

• Proceedings of the Korea Society of Design Studies Conference
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• 2001.10a
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• pp.66.1-66
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• 2001

• Journal of the Korean Statistical Society
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• v.7 no.2
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• pp.99-100
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• 1978

This note is to demonstrate that the extention of Theorem 4.15 of Graybill on the independence of quadratic forms is possible. For the self-contained exposition, Theorem 4.15 is rewritten.

• Water Engineering Research
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• v.3 no.2
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• pp.135-142
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• 2002

This study investigates the effects of sediment on the flow characteristics such as velocity distribution, friction velocity, turbulent intensities, Reynolds stress, etc. Particle tracking velocimetry (PTY) is used to measure the vertical flow field. Results show that flow over the high bed-load concentration region has larger values of mean velocity and friction velocity and smaller values of turbulence intensities, compared to those for flow over the low bed-load concentration region.