• 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 Biosystems Engineering
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• v.27 no.4
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• pp.349-354
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• 2002

In this study, we proposed a web-based teleoperation system to enhance the productivity and flexibility of the greenhouse since basically, internet-based teleoperation enables cheap, expandable system to be implemented. Platform independent language, Java-based control system can overcome the platform dependency which most of conventional control systems have. One of the merits of the proposed system is the flexibility of the data based system from which some valuable analysis can be implemented on-line. Some basic experiments show the stability and field applicability of the proposed remote control system.

• Journal of Biosystems Engineering
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• v.26 no.4
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• pp.363-370
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• 2001

This study intended to estimate the willingness-to-pay amount by farmers for the automatic guidance technology of Combine. Contingent Valuation Method was employed for this estimation using survey data from 65 Combine using farmers. Based on the dichotomous choice model, farmers’willingness-to-pay for the automatic guidance technology was ranged from ￦4,772,000(median) to ￦5,268,000(mean). The estimated willingness-to-pay by the for the new technology was approximately one quarter of the average value based on the willingness-to-pay for the new technology was approximately one quarter of the average value of Combine in sample farms. This implies that there is an economic rationals for developing the new technology as long as it will be available with the cost less than the amount of estimated willingness-to-pay.

• Journal of Biosystems Engineering
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• v.25 no.5
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• pp.341-350
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• 2000

This study was conducted to develop a control unit for a tying device of a variable chamber round baler. The work process of the tying device was thoroughly analyzed and the control sequence was established according to the work process. Based on this control sequence, a control unit using an 8 bit microprocessor AT 89C52 as a CPU was developed. The driving circuit to control the actuator motion was developed and the PWM method was used to regulate the velocity of the actuator. On the front panel of the control unit, indicators were also installed to show the operations being conducted. A prototype of the developed control unit was manufactured and tested. A total of 50 complete cycles of the control sequence was repeated and no failure was observed. It was evaluated that the developed control unit has an excellent performance and can be used practically for variable chamber round balers.

• Communications for Statistical Applications and Methods
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• v.6 no.3
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• pp.849-860
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• 1999

This paper addresses the issue of estimating regression function with errors in variables using wavelets. We adopt a nonparametric approach in assuming that the regression function has no specific parametric form, To account for errors in covariates deconvolution is involved in the construction of a new class of linear wavelet estimators. using the wavelet characterization of Besov spaces the question of regression estimation with Besov constraint can be reduced to a problem in a space of sequences. Rates of convergence are studied over Besov function classes $B_{spq}$ using $L_2$ error measure. It is shown that the rates of convergence depend on the smoothness s of the regression function and the decay rate of characteristic function of the contaminating error.

• Communications for Statistical Applications and Methods
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• v.6 no.3
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• pp.957-966
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• 1999

We evaluate the accuacy and precision of maximum likelihood estimation procedures for infectivity of HIV in partner studies. This is achieved by applying the oricedyre typothetical samples generated by computer. One hundred samples were generated with various combinations of parameters. The estimation procedure was found to be quite accurate. in addition it was found that the power of the test for equality of infectivities for two types of contact depends on sample size and length of observation period but not on the number of observations made on each subject. Tests based on a model for the infectivity had higher power than standard methods for comparing proportions.

• Journal of the Korean Statistical Society
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• v.9 no.1
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• pp.79-94
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• 1980

This paper illustrates the application of the Box-Jenkins techniques for analyzing the monthly data of money supply from January 196 to December 1977 of Korea.

• Journal of Home Health Care Nursing
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• v.14 no.2
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• pp.106-114
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• 2007

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.17 no.2
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• pp.125-134
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• 2014

• The Journal of the Korean dental association
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• v.23 no.1 s.188
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• pp.59-66
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• 1985