• Journal of Institute of Control, Robotics and Systems
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• v.7 no.4
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• pp.288-294
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• 2001

In this study, a new PWM method considering the actuation delay of high speed solenoid valves is proposed to improve the response characteristics of electro hydraulic servo systems controlled by high speed solenoid valves. In addition, the decision method for the system gain, the basic period of PWM, and the sampling time is proposed, Since the conventional system controlled by high speed solenoid valves is too slow to apply this method, a high speed driving circuit(Quick-Drive) which enables rapid switching of the high speed solenoid valve at a high speed sampling mode is applied to realize this method. The experimental result shows that it is possible to achieve precision and quiet control without occurrence of limit cycle and wide range dead band.

• Journal of Power System Engineering
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• v.6 no.2
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• pp.82-87
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• 2002

For the dynamic behavior evaluation of a semi-active vibration control system, it is very important to use an accurate mathematical model for the hydraulic damper applied to the control system. In this study, a mathematical model for a symmetric type hydraulic damper was suggested. In this model, the effects of gas volume and oil temperature variation on the bulk modulus of oil were considered. The dynamic behavior of the damper was investigated by experiments and simulations. It was confirmed that the pressure variation, damping force, and mean pressure variation could be estimated with comparatively good precision by the suggested mathematical model. Moreover, it was shown that excessive pressure rise can be generated by the oil expansion due to the heat energy transformed from the exciting energy of the damper for a short period of the damper operation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.48 no.1
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• pp.17-19
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• 2003

The purpose of this study was to evaluate the effect of pesticides on insect pest control of Rhophalosiphum nymphaeae, growth characteristies and dry root yield from the cultivated after early maturing rice cropping. All pesticides treated had no effect on the growh period, flowering rate of Alisma plantago. The major pesticides were methomyl-Lf, 24.1 %, imidacloprid-Wp, 10%, carbosulfan-Wp, 20%, and methomyl-Wp, 45%. Dry yield of root were increased largely with imidacloprid-Wp, 10% (10g/20$\ell$), pesticide than the other pesticides and control. All pesticides were had no injury with recommended concentration. On the other hand all pesticides were slightly harmful in the double dosage level for the Alisma plantago.

• Journal of Ginseng Research
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• v.16 no.2
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• pp.146-150
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• 1992

Life history, ginseng damage, and chemical control of the snail Acusta despecta sieboldiana Pfeiffer were investigated in the field and laboratory conditions from 1987 to 1990. Eggs of the snail were whitish globular and 1.,93${\pm}$ 0.09 mm in diameter which were deposited as egg mass composed of 28.4${\pm}$ 15.4 eggs. Egg period was 11.8${\pm}$ 1.6 days under the laboratory condition. Most eggs were laid during mid July in the field. The snail had a life cycle of a year and hibernated from November to April. Significant ginseng damages by the snail (over 10% to the total number of plants) were observed only in the three to five year old ginseng fields with rice straw mulching. Based on the dates that the first ginseng damages were observed and on the questionary examination, ginseng damages seemed to occur from May to July. Metaldehyde (6%) bait showed reliable control effects on the snail.

• International Journal of Fuzzy Logic and Intelligent Systems
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• v.14 no.1
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• pp.26-33
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• 2014

This study addresses the control problem of an unmanned aerial vehicle (UAV) during the transition period when the flying mode changes from hovering to translational motion in the horizontal plane. First, we introduce a compensation algorithm that improves height stabilization and reduces altitude drop. The main principle is to incorporate pitch and roll measurements into the feedforward term of the altitude controller to provide a larger thrust force. To further improve altitude control, we propose the fuzzy logic controller that improves system behavior. Simulation results presented in the paper highlight the effectiveness of the proposed controllers.

• Korean journal of applied entomology
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• v.2
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• pp.12-15
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• 1963

1. The trials were planned to test seven different fungicides for the control of Early blight of potato during the period of 1962 and 1963. 2. All of fungicides tested in the trials were considerably effective to control the disease, as the result of 4 applications which was done in one week intervals from early of June in 1963. All treatments were effective enough to make significant differences from the untreated. Especially, Dithyane M45, Difolatan and Dithane M22 showed satisfactory control even though no significant differences were obtained among them. Besides the three treatments, Bordeaux Mixture were relatively effective.

• International Journal of Control, Automation, and Systems
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• v.6 no.1
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• pp.44-53
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• 2008

An interacting multiple model (IMM) estimation algorithm based on the mixing of the predicted state estimates is proposed in this paper for a right continuous jump-linear system model different from the left-continuous system model used to develop the existing IMM algorithm. The difference lies in the modeling of the mode switching time. Performance of the proposed algorithm is compared numerically with that of the existing IMM algorithm for noisy system identification. Based on the numerical analysis, the proposed algorithm is applied to target tracking with a large sampling period for performance comparison with the existing IMM.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.39-40
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• 2017

This study aims to evaluate the humidity control performance of low-priced generic ceramic panels that are used to control humidity. Temperature and humidity are monitored by using 'Living Lab' and the change of indoor relative humidity is measured and analyzed. According to the results of the study, the indoor relative humidity of rooms installed with ceramic panels was found to be low compared to that of living rooms by 2.2%RH (test period) and 3.2%RH (daily). In the case of maximum relative humidity, rooms installed with ceramic panels were found to be low by 6.9%RH. The results are attributable to the humidity absorption of ceramic panels. Accordingly, future ceramic panels need the improvement of performance and an appropriate construction area should be derived depending on indoor space.

• Journal of Electrical Engineering and Technology
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• v.3 no.2
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• pp.285-291
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• 2008

Active Queue Management(AQM) has been widely used for congestion avoidance in Transmission Control Protocol(TCP) networks. Although numerous AQM schemes have been proposed to regulate a queue size close to a reference level, most of them are incapable of adequately adapting to TCP network dynamics due to TCP's non-linearity and time-varying stochastic properties. To alleviate these problems, we introduce an AQM technique based on a dynamic neural network using the Back-Propagation(BP) algorithm. The dynamic neural network is designed to perform as a robust adaptive feedback controller for TCP dynamics after an adequate training period. We evaluate the performances of the proposed neural network AQM approach using simulation experiments. The proposed approach yields superior performance with faster transient time, larger throughput, and higher link utilization compared to two existing schemes: Random Early Detection(RED) and Proportional-Integral(PI)-based AQM. The neural AQM outperformed PI control and RED, especially in transient state and TCP dynamics variation.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.4
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• pp.272-281
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• 2000

This paper deals with the parallel operation of several numbers of PWM converters for a high speed railway train application. Several considerations are made to reduce the transformer interaction which can cause a current control problem in severe case. Also, in this paper, novel control strategy is proposed to achieve a harmonic free primary-side current control under a light load condition using one current sensor independent of the number of converters. In addition, the modified predictive current controller, which is suitable to a digital current controller with a relatively large sampling period, is used. Finally, to verify the system validity, digital control system with TMS320C44 micro-processor and small scale simulator are made and tested.