• Structural Engineering and Mechanics
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• 제14권1호
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• pp.21-38
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• 2002

A control algorithm combining viscous and non-linear Reid damping mechanisms has been recently proposed by the authors to command active friction dampers. In this paper, friction dampers and the proposed algorithm are applied to control the seismic responses of a nonlinear 20-story building. Piezoelectric stack actuators are used to implement the control algorithm. The capacity of each damper is determined by the practical size of piezoelectric actuators and the availability of power supply. The saturation effect of the actuators on the building responses is investigated. To minimize the peak story drift ratio or floor acceleration of the building structure, a practical sequential procedure is developed to sub-optimally place the dampers on various floors. The effectiveness of active friction dampers and the efficiency of the proposed sequential procedure are verified by subjecting the building structure to four earthquakes of various intensities. The performance of 80 dampers and 137 dampers installed on the structure is evaluated according to 5 criteria. Numerical simulations indicated that the proposed control algorithm effectively reduces the seismic responses of the uncontrolled 20-story building, such as inelastic deformation. The sub-optimal placement of dampers based on peak acceleration outperforms that based on peak drift ratio for structures subjected to near-fault ground motions. Saturation of piezoelectric actuators has adverse effect on floor acceleration.

• Journal of Power Electronics
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• 제11권2호
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• pp.156-162
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• 2011

The control loop time delay caused by sampling, the zero-order-holder effect and calculations is inevitable in the digital control of dc-dc switching converters. The time delay will limit the bandwidth of the control loop and therefore degrade the transient performance of digital systems. In this paper, the quantization time delay effects with different time delay values based on a generic second-order system are analyzed. The conclusion that the bandwidth of digital control is reduced by about 20% with a one cycle delay and by 50% with two cycles of delay in comparison with no time delay is obtained. To compensate the time delay and to increase the control loop bandwidth, a duty ratio predictive control scheme based on linear extrapolation is proposed. The compensation effect and a comparison of the load variation transient response characteristics with analogy control, conventional digital control and duty ratio predictive control with different time delay values are performed on a point-of-load Buck converter by simulations and experiments. It is shown that, using the proposed technique, the control loop bandwidth can be increased by 50% for a one cycle delay and 48.2% for two cycles of delay when compared to conventional digital control. Simulations and experimental results prove the validity of the conclusion of the quantization effects of the time delay and the proposed control scheme.

• 한국소음진동공학회논문집
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• 제21권6호
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• pp.506-513
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• 2011

This paper is concerned with a study on the control effect of the MR damper using the cutout piston. The MR damper has passive damping force by the oil pressure and controllable damping force by the magnetic effect. As the velocity of the MR damper's piston increases the passive damping force increases and the ratio of the controllable damping force to the total damping force is decreased. Consequently, the control performance of the MR damper is reduced according to the increase of the velocity. In this paper, the cutout piston concept is applied to the MR damper to improve MR damper's control performance by reducing the passive damping effect. The MR damper with the cutout piston has been designed and manufactured and its hydraulic and electromagnetic analysis has been performed to predict its performance. The control performances of the MR damper with the cutout piston are verified through the comparison of experiment results and simulation results.

• 한국약용작물학회지
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• 제23권6호
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• pp.473-479
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• 2015

Background : To control ginseng gray mold, farmers have mainly used inorganic chemical based fungicides. The recent emergence of fungicide resistance has reduced the effectiveness of such control methods. Such pesticides also carry additional problems, such as diffuse pollution. Methods and Results : Six treatments of organic agricultural materials were tested for control of ginseng gray mold, CAPW (Chrysophanic acid + Phytoncide + Wood vinegar), EmEWV (Emodin + Ethanol + Wood vinegar), CEWV (Curcumin + Eugenol + Wood vinegar), Bacillus subtilis, soybean oil and sulfur. The control effect for gray mold by a single application of the agrochemical fungicide industrial Fenhexamid wettable powder (WP) was 84.4%. The control effect by CAPW, EmEWV and CEWV varied between 52.7 - 64.9%. The control effect by B. subtilis, soybean oil, and sulfur were 32.9 - 59.2%. Conclusions : In the field tests, CAPW showed the highest control effects when used before, and at first stage of disease incidence, against ginseng gray mold.

• 대한간호학회지
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• 제35권1호
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• pp.56-64
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• 2005

Purpose: The purpose of this study was to verify the effect of aromatherapy massage on constipation in the elderly. Method: This study for 10 day, employed a randomized control group pretest-posttest design. The experimental group received abdominal massage using essential oils with Rosemary, Lemon, and Peppermint, and the control group received a placebo massage. To evaluate the effect of aromatherapy, the degree of constipation was measured using the CAS (constipation assessment scale) and the number of bowel movements per week. Data was analyzed by repeated measures of ANOVA using the SPSS program. Result: The score of CAS of the experimental group was significantly lower than that of the control group. In addition the average number of bowel movements in the experimental group was higher than that of the control group. The effect of aromatherapy lasted 2 weeks after treatment, while the placebo effect lasted 7~10 days after treatment. Conclusion: The finding of this study showed that aromatherapy helps relieve constipation in the elderly.

• 유통과학연구
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• 제15권1호
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• pp.105-114
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• 2017

Purpose - Recently, domestic pharmaceutical market is growing steadily, but top-tier companies are concentrating on sales growth. In this market, SMEs, which account for more than 80% of the entire market, suffer from the problem of lower margins and increasing inventory costs. According to the government's policy changes related to pharmaceuticals, it is pointed out that the management of existing customers and the control of salespeople are important issues for pharmaceutical companies. This study investigates the effect of the control system on the salesperson in domestic pharmaceutical distribution channel on customer-oriented selling behaviors and sales performance. Research design, data, and methodology - To verify the proposed research model and test hypotheses, the authors selected 244 MR(medical representatives)'s responses which have currently relationship with doctors or pharmacists. This study carefully investigated the reliability, content validity, convergent validity, and discriminant validity of the proposed model. Results - The authors find out the following results: capacity control, activity control, and self control have positive effects on customer-oriented selling behaviors and customer-oriented selling behaviors have a positive effect on sales performance. In addition, we present alternative model to check the direct effect between the control systems and the sales performance, but control system factors except self control have no direct influence. Conclusions - First of all, competency control and activity control increases the customer-oriented selling behavior of the salesperson. This means that the salesperson's sales skill, negotiation skill, customer access skill, presentation ability, monitoring, direction and evaluation are important and it is also important to control activities to check the number of visits to customers, report preparation, and customer service etiquette. Second, the fact that self-control of salesperson affects the customer-oriented selling behavior suggests that self-control is not controlled by external factors but rather establishes short/long-term goals. Therefore, it is important for sales organization to create an environment in which members can induce persistent incentives for self-control. Finally, output control did not affect customer-oriented sales behavior, which is less likely to form confidence or motivation to MRs when output control is perceived as a means of monitoring, supervising, or controlling rather than providing information to salespeople.

• 아동학회지
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• 제38권3호
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• pp.19-32
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• 2017

Objective: This study examined whether the effects of fathering on school children's effortful control would be moderated by fathers' and mothers' own effortful control. Methods: The sample included 371 fourth grade children (47% boys) and their parents. Father's positive and negative parenting behaviors, parents' own effortful control and children's effortful control were assessed. Data were analyzed using hierarchical multiple regression in SPSS 18.0. Results: Parents' effortful control appeared to moderate the effect of fathering on children's effortful control. More specifically, parents' high levels of effortful control increased the effects of positive fathering on children's effortful control. Conclusion: Findings indicated that parents' effortful control tended to increase the effects of positive fathering (and lower the effects of negative fathering). This supports the importance of parents' effortful control in the development of school children's effortful control.

• 대한물리의학회지
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• 제7권4호
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• pp.443-450
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• 2012

PURPOSE: This study was investigated to find the validity of active movement control test for low back pain patients with or without hamstring shortening. METHODS: The subjects of this study were 28 subjects and all of them agreed to participate in the study. All subjects were classified according to 4groups. Group1 was no LBP, no hamstring shortening. Group2 was no LBP, hamstring shortening. Group3 was LBP, no hamstring shortening. Group4 was LBP, hamstring shortening. We measured to see their low back pain and hamstring shortening with VAS, Goniometer for active movement control test. We analyzed the data using Cochran Q test and crosstabulation for agreement index. RESULTS: The results of this study were as follows : 1) Low back pain had effect on active movement control by Group1 and Group2. 2) Hamstring had effect on active movement control by Group1 and Group2 3)Low back pain with or without hamstring shortening had effect on active movement control by Group4 CONCLUSION: According the results of this study, active movement control test were significantly influenced on low back pain and hamstring interaction.

• 대한기계학회논문집A
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• 제28권8호
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• pp.1075-1086
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• 2004

In this paper, Time Delay Control(TDC) for robot manipulators is analyzed and its problems are founded. In order to remedy the problems, the enhanced controller is proposed and analyzed. The effect of friction associated with TDC is reported and its cause is presented. Through the analysis, simulation and experiment, it is shown that the friction effect causes serious degradation in control performance and that it is a result of the error of Time Delay Estimation(TDE) in TDC. In order to remedy the problems, TDC combined with Internal Model Control(IMC) concept is proposed. The proposed compensator is effective enough to handle the bad effect of friction, and is so simple and efficient as to match positive attribute of TDC. The simulation and experimental results show the effectiveness of proposed controller against the friction of the robot manipulators.

• 한국환경과학회지
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• 제30권12호
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• pp.993-1003
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• 2021

It is known that the effect of traditional agricultural techniques of burning farmland such as paddy fields and fields gradually declines and affects both the fauna and flora of the rice paddy as well as pests. Therefore, in this study, a study was conducted to investigate the effects of burning rice paddy fields and rice paddy fields levee on the control effect of winter pests inhabiting agricultural land and the amount of pests generated and damaged during the growing season. As a result of this study, the pest control effect of incineration reduces not only the density of pests, but also beneficial insects (natural enemies) and non-reptiles. It is judged that burning has a very low insect control effect. It is expected to be used as basic data to create a sustainable agricultural environment, such as minimizing various negative effects such as pest control effects, wildfires, and air pollution caused by incineration, and suppressing unnecessary incineration and fine dust generation.