• 대한전기학회논문지
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• 제45권1호
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• pp.60-66
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• 1996

Brushless DC(BLDC) motor have been increasingly used in machine tools and robotics applications due to the reliability and the efficiency. In control of BLDC motor, it is important to construct the controller which is robust to parameter variations and external disturbances. Variable structure controller(VSC) has been known as a powerful tool in robust control of time varying systems. In practical systems, however, VSC has a high frequency chattering which deteriorates system performances. In this paper, a binary controller(BC) which takes the form of VSC and MRAC combined is presented to solve this problem. BC consists of the primary loop controller and the external loop controller to change the gain of primary loop controller smoothly. So it can generate the continuous control input and is insensitive to parameter variations in the given domain. To confirm the validity, various investigations of control characteristics for various design parameters in a position control system of BLDC motor are carried out. (author). 11 refs., 18 figs., 1 tab.

• 상하수도학회지
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• 제20권6호
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• pp.829-836
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• 2006

The reaction rate of denitrification is primarily affected by the utilization of organics that are usually limited in the anoxic period in a sequencing batch reactor. It is necessary to add an extemal carbon source for sufficient denitrification. An adaptive model of state-space based on the extended Kalman filter is applied to manipulate the dosage rate of extemal carbon automatically. Control strategies for denitrification have been studied to improve control performance through simulations. The normal control strategy of the constant set-point results in the overdosage of external carbon and deterioration of water quality. To prevent the overdosage of external carbon, improved control strategies such as the constrained control action, variable set-point, and variable set-point after dissolved oxygen depletion are required. More stable control is obtained through the application of the variable set-point after dissolved oxygen depletion. The converging value of the estimated denitrification coefficient reflects conditions in the reactor.

• 한방안이비인후피부과학회지
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• 제27권1호
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• pp.1-16
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• 2014

Objectives : The aim of this study is to examine the effect of external application containing herbal extracts (Betula platyphyllae Cortex, Viticis Fructus, Agrimoniae herba) to patients with atopic dermatitis. Methods : Twenty patients (experiment group) were treated with the external application containing herbal extracts (Betula platyphyllae Cortex, Viticis Fructus, Agrimoniae herba) and other twenty patients (control group) were treated with normal external application that doesn't contain herbal extracts for 2weeks. We observed comparisons between experiment and control group after 1week, 2weeks. Degrees of severity of atopic dermatitis were measured by SCORAD index (Scoring of Atopic Dermatitis Index). Statistical significance was achieved if the probability was less than 5% (p<0.05). Results : 1. After 1week of external application treatment, SCORAD Index in experiment group was significantly decreased comparing with control group, which is a marginally significant result between two groups. But after 2weeks the experiment group showed no statistically significant result. 2. After 1week of external application treatment, Intensity Criteria (Erythema, Edema/papulation, Total) in experiment group was significantly decreased comparing with control group, which is a statistically significant result between two groups. But after 2weeks the experiment group showed no statistically significant result. 3. After 1week and 2weeks of external application treatment, comparison of changes in Subjective Symptoms (Pruritus, Insomnia) indicated that the experiment group showed no statistically significant result. 4. After 1week of external application treatment, Total Quality of life through Skindex-29 in experiment group was significantly decreased comparing with control group, which is a marginally significant result between two groups. But after 2weeks the experiment group showed no statistically significant result. Conclusions : As a result of applying the external application containing herbal extracts to patients with atopic dermatitis and watching the progress, we can speculate that the external application containing herbal extracts has especially short-term therapeutical effects in mitigating the symptoms of Atopic Dermatitis. Thus, it is concluded and considered that the external application containing herbal extracts can be used by atopic patients effectively with almost no side-effect.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1996년도 Proceedings of the Korea Automatic Control Conference, 11th (KACC); Pohang, Korea; 24-26 Oct. 1996
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• pp.111-114
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• 1996

This paper proposes a robust control method using Universal Learning Network(U.L.N.) and second order derivatives of U.L.N.. Robust control considered here is defined as follows. Even if external input (equal to reference input in this paper) to the system at control stage changes awfully from that at learning stage, the system can be controlled so as to maintain a good performance. In order to realize such a robust control, a new term concerning the perturbation is added to a usual criterion function. And parameter variables are adjusted so as to minimize the above mentioned criterion function using the second order derivative of the criterion function with respect to the parameters.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.76-81
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• 2004

Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

• Journal of Mechanical Science and Technology
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• 제18권8호
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• pp.1388-1400
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• 2004

Problems with the control, oscillatory motion and compliance of pneumatic systems have prevented their widespread use in advanced robotics. However, their compactness, power/weight ratio, ease of maintenance and inherent safety are factors that could be potentially exploited in sophisticated dexterous manipulator designs. These advantages have led to the development of novel actuators such as the McKibben Muscle, Rubber Actuator and Pneumatic Artificial Muscle Manipulators. However, some limitations still exist, such as a deterioration of the performance of transient response due to the changes in the external inertia load in the pneumatic artificial muscle manipulator. To overcome this problem, a switching algorithm of the control parameter using a learning vector quantization neural network (LVQNN) is newly proposed. This estimates the external inertia load of the pneumatic artificial muscle manipulator. The effectiveness of the proposed control algorithm is demonstrated through experiments with different external inertia loads.

• 수면정신생리
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• 제5권1호
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• pp.34-44
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• 1998

Living organisms are influenced by many external rhythms and they have adapted their physiology to periodically changing conditions. These adaptive strategies are controlled by endogenous innate programs of behavior and physiology which are determined by external signals ("Zeitgeber"). There are many biological rhythms, each with its own characteristic functional adaptation. Among them, the presence of endogenous time control of feeding and drinking becomes obvious. There are increasing evidences that the control of food intake, food selection, and drinking are regulated by the endogenous rhythms including a circadian rhythm. However, there have been many restrictions in understanding the endogenous control of food intake itself and its mechanism. To broaden our know ledges of the endogenous time control of feeding and drinking, the author reviwed the characteristics of the endogenous timing for food intake, the influence of circadian pacemakers and food-entrainable oscillators, the interaction between the circadian control and the external and internal conditions in the control of food intake, the conseqences of feeding, the circadian control of food selection, and the biological cycles in energy balance.

• 제어로봇시스템학회논문지
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• 제11권2호
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• pp.103-108
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• 2005

Loading/Unloading task in the real industry is performed by crane, but most of the loading/unloading task with the weight of 5kg∼30kg is done by human workers and this kind of work causes industrial disaster of workers. Therefore it is necessary to develop low cost loading/unloading manipulator system to prevent this kind of industrial accidents. This paper is concerned with the design and fabrication of 2 axis pneumatic manipulators using on/off solenoid valves and accurate position control without respect to the external load and low damping in the pneumatic rotary actuator. To overcome the change of external load, switching of control parameter using LVQNN (Learning Vector Quantization Neural Network) is newly applied, which estimates the external loads in the pneumatic cylinder. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied to the switching control system. The effectiveness of the proposed control algorithms are demonstrated through experiments of pneumatic cylinder with various loads.

• Safety and Health at Work
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• 제10권2호
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• pp.205-212
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• 2019

Background: Workforce health is one of the primary and most challenging issues, particularly in industrialized countries. This article aims at modeling the major factors affecting accidents in the workplace, including general health, work-family conflict, effort-reward imbalance, and internal and external locus of control. Methods: A cross-sectional study was conducted in Esfahan Steel Company in Iran. A total of 450 participants were divided into two groups-control and case-and the questionnaires were distributed among them. Data were collected through a 7-part questionnaire. Finally, the results were analyzed using SPSS 22.0 and Amos software. Results: All the studied variables had a significant relationship with the accident proneness. In the case group, general health with a coefficient of -0.37, worke-family conflict with 0.10, effort-reward imbalance with 0.10, internal locus of control with -0.07, and external locus of control with 0.40 had a direct effect on occupational stress. Occupational stress also had a positive direct effect on accident proneness with a coefficient of 0.47. In addition, fitness indices of control group showed general health (-0.35), worke-family conflict (0.36), effort-reward imbalance (0.13), internal locus of control (-0.15), and external locus of control (0.12) have a direct effect on occupational stress. Besides, occupational stress with a coefficient of 0.09 had a direct effect on accident proneness. Conclusion: It can be concluded that although previous studies and the present study showed the effect of stress on accident and accident proneness, some hidden and external factors such as work-family conflict, effort-reward imbalance, and external locus of control that affect stress should also be considered. It helps industries face less occupational stress and, consequently, less occurrence rates of accidents.

• 대한지역사회영양학회지
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• 제29권2호
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• pp.114-128
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• 2024

Objectives: The purpose of this study was to investigate the perception of nutrition teachers and the factors influencing their intention toward sustainable dietary education utilizing the theory of planned behavior (TPB). Methods: The self-administered online survey was completed by nutrition teachers in Jeollanam-do, South Korea. A total of 151 valid questionnaires were analyzed. Factor analysis and multiple regressions were employed to test the research model. Results: The study findings demonstrated that all TPB variables significantly influenced the sustainable dietary educational intention, with the degree of influence ranking as follows: external perceived behavioral control (β = 0.417), attitude (β = 0.240), internal perceived behavioral control (β = 0.207), and subjective norms (β = 0.181). For external perceived behavioral control, nutrition teachers and elementary schools exhibited higher levels compared to dietitians and middle/high schools, respectively. The participants in sustainable dietary education training programs exhibited a higher level of internal perceived behavioral control compared to those who did not participate. The highest perception levels were reported for attitude (4.26), followed by subjective norms (4.02), internal perceived behavioral control (3.67), and external perceived behavioral control (3.20). Conclusions: This study affirmed that the TPB variables elucidated the sustainable dietary educational intentions of nutrition teachers. The significant impacts of external and internal perceived behavioral control, attitude, and subjective norms on educational intentions were confirmed. Consequently, proactive support from schools and governments is essential to enhance the facilitating factors and mitigate the barriers toward sustainable dietary education in schools.