• Journal of Institute of Control, Robotics and Systems
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• v.6 no.9
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• pp.803-812
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• 2000

In this paper we introduce a model based centralized hierarchical controller for cooperative team of soccerplaying multiple mobile robots. The hierarchical controller is composed of high-level and low-level controllers. Using the coordinates information of objects from the vision are simple models of multiple mobile tobots on the playground. Subsequently, the high level controller selects and action model corresponding to the perceived state transition model and generates subgoal and goal-velocity, from which the low level controller generates trajectory of each wheel velocity of the robot. This two layered simplicity. The feasubility of the control strategy has been demonstrated in an implementation for real soccer games at a MiroSot league.

• Journal of Institute of Control, Robotics and Systems
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• v.14 no.2
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• pp.105-110
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• 2008

This paper presents a control method to maintain stable mold level for unsteady bulging in high speed casting. The stabilizing mold level is an important factor to get high quality products. But, for various reasons, there are several disturbance factors which make mold level unstable. Bulging is one of disturbance factors and considered for the current stage of study. We design a disturbance observer to attenuate the effect of bulging which is periodic mold level disturbance. Since the period of bulging varies with the casting speed, the parameters of disturbance observer are changed by the casting speed. Simulation is illustrated to demonstrate stable performance of the proposed method in comparison with a previous method in a variable operating frequency.

• Nuclear Engineering and Technology
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• v.44 no.8
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• pp.911-918
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• 2012

Steam generator level control at low power is difficult due to its adverse thermal hydraulic properties, and is usually conducted by an operator. The basic model predictive control (MPC) is similar to the action of an operator in that the operator knows the desired reference trajectory for a finite period of time and takes the necessary control actions needed to ensure the desired trajectory. An MPC is based on a model; the performance as well as the efficiency of the MPC depends heavily on the exactness of the model. In this study, steam generator models that can describe in detail its thermal hydraulic behaviors, particularly at low power, are used in the MPC design. The design scope is divided into two parts. First, the MPC feedwater controller of the feedwater station is determined, and then the MPC level controller for the overall system is designed. Because the dynamic properties of a steam generator change with the power levels, a realistic situation is simulated by changing the transfer functions of the steam generator at every time step. The resulting MPC controller shows good performance.

• Journal of Power Electronics
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• v.11 no.4
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• pp.583-590
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• 2011

Three-level NPC inverters have been put into practical use for years especially in high voltage high power grids. This paper researches three-level active power filters (APFs). In this paper a mathematical model in the d-q coordinates is presented for 3-phase 3-wire NPC APFs. The deadbeat control scheme is obtained by using state equations. Canceling the delay of one sampling period and providing the predictive value of the harmonic current is a key problem of the deadbeat control. Based on this deadbeat control, the predictive output current value is obtained by the state observer. The delay of one sampling period is remedied in this digital control system by the state observer. The predictive harmonic command current value is obtained by the repetitive predictor synchronously. The repetitive predictor can achieve a better prediction of the harmonic current with the same sampling frequency, thus improving the overall performance of the system. The experiment results indicate that the steady-state accuracy and the dynamic response are both satisfying when the proposed control scheme is implemented.

• Journal of the Korean Society of Food Culture
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• v.18 no.4
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• pp.396-405
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• 2003

The purpose of this study was to investigate the changes of obesity and depression level of obese children on body weight control program. The body weight control program included nutrition education, psychotherapy and exercise for weekly session during 9 months. The results from this study were as follows. A total of 27 obese children participated in this study. The average age of children was 11.7 years, 70% of children had regular exercise. Average exercise time was 1.2 hours and watching television time was 1.8 hours. Children's serum composition were within normal ranges. Rohrer index(RI) was significantly decreased to 163 from 167(p<0.001) and BMI was significantly decreased to 23.9 from 24.5(p<0.01) after body weight control program. There was not significant difference in depression score after body weight control program and there was not significant correlation between obesity and depression level. The response tendency of depression items indicated obese children had negative depression feelings and couldn't have hopeful mind to the future. But there were significant increase(p<0.05) in depression and hopeful mind in factor analysis. The suggestion and limitations of this study were discussed. These results suggest that body weight control program including nutrition education, exercise and psychotherapy may be effective for helping obese children.

• Proceedings of the IEEK Conference
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• 2000.09a
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• pp.533-536
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• 2000

We consider the design of quadrature amplitude modulation (QAM) transceivers f3r fixed wireless communications. The use of adaptive power control in the transmitter (Tx) can provide BER performance robust to fading and improved BER performance. The BER performance is evaluated by analytical and simulation results when multi-level QAM transceiver employing power control in the Tx is applied to fixed wireless channel with flat fading and frequency selective fading. The effect of power control parameters such as power control range and power control step size is investigated

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.1229-1232
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• 1996

This paper proposes the passive redundancy algorithm of multi-controller structure applicable to the steam generator level control system in the low power operating range. In the passive redundancy scheme of multi-controller structure, two suitable controllers exist if the plant is strongly stabilizable. One of the two controllers can be selected arbitrarily only if it is stable. In particular, this paper shows that the passive redundancy scheme can be efficiently used with PID and GPC control algorithms through simulation studies on the control of the steam generator.

• Journal of Biomedical Engineering Research
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• v.18 no.1
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• pp.79-86
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• 1997

This paper describes the development of portable arousal measurement and analysis system. Skin impedance change which responds to the change of arousal level was detected by the three elctrode constant current method and separated into two components(SIR, SIL). Relationship between Nz, IRI and arousal level was studied and criteria of arousal level control was decided by the sleep study. Measured data with and without warning signal were compared and analyzed.

• Korean Journal of Food Science and Technology
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• v.32 no.6
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• pp.1418-1425
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• 2000

Obesity and diabetes mellitus are associated with common pathogenic mechanism, and ${\beta}-glucan$ of Agaricus blazei Murill is potent inhibitor of intestinal ${\alpha}-glycosidase$ and inhibit the digestion of starch and sucrose in the small intestine. In this studies, there was observed the anti-hyperglycemic effect in obese diabetic mice(C57BLKsJ db/db), which were supplied Agaricus and Acarbose for 5 weeks. In db/db mice, food intake and body weight gain were decreased significantly in Agaricus groups(p<0.05). Also these group exhibited lower fasting serum glucose level compared with control group. HbA1c level, triglyceride level, total cholesterol level, HDL cholesterol level, LDL cholesterol level and VLDL cholesterol level were lowered in db/db mice. The activity of disaccharidases on proximal and distal segments of small intestine was decreased. In conclusion, it was assumed that ${\beta}-glucan$ of Agaricus blazei Murill has anti-hyperglycemic and anti-obesitic effects by reducing food intake and body weight gain, and also decreasing serum glucose and lipid level through inhibiting the activity of small intestinal disaccharidases.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.12
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• pp.1035-1042
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• 2016

By using commercial flight simulation game engine, X-Plane, we have studied QTG(Qualification Test Guide) generation that can satisfy FTD level 5. Flight model is SR-20 of Cirrus. In list of QTG, There are some items to measure control forces. therefore, we have installed CLS(Control Loading System) to flight control devices in order to make it possible to measure control forces. We made Autopilot function externally to make flight model in trim conditions because X-Plane don't provide internal trim routine function. In addition to develop an algorithm, it can automatically perform the test. To avoid the inconvenience to control as it was to be carried out in same conditions. In case of FTD level 5, it is possible to use alternative data sources not only real flight data. By using these alternative data sources, all test results satisfy a scope given by CFR Part 60.