• International Journal of Control, Automation, and Systems
• /
• v.6 no.4
• /
• pp.620-625
• /
• 2008

The $H_{\infty}$ entropy in $H_{\infty}$ control theory is discussed based on investigating information transmission in continuous-time linear stochastic systems. It is proved that the stabilizing feedback does not change the time-average information transmission between system input and output, and the $H_{\infty}$ entropies of open- and closed-loop stable transfer functions are bounded by mutual information rate between input and output in the open-loop system. Furthermore, a new $H_2$ upper bound for $H_{\infty}$ entropy is introduced with a numerical example. Thus the $H_{\infty}$ entropy of a stable transfer function is sandwiched between $H_2$ norms of the original system and a static feedback system.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.4 no.1
• /
• pp.43-49
• /
• 1999

We propose a nonlinear feedback controller that can control the induction motors with high dynamic performance and high power efficiency by means of decoupling of motor speed and rotor flux. The nonlinear feedback controller needs the information on some motor parameters. New recursive adaptation algorithms for rotor resistance and mutual inductance which can be applied to our nonlinear feedback controller are also presented in this paper. The recursive adaptation algorithms make the estimated values of rotor resistance and mutual inductance track their real values. Some simulation and experimental results show that the adaptation algorithms are robust against the variation of stator resistance and stator inductance.

• 제어로봇시스템학회:학술대회논문집
• /
• 1996.10b
• /
• pp.1253-1256
• /
• 1996

In this paper, a new nonlinear feedback linearization control scheme for induction motors is developed. The control scheme employs a fuzzy nonlinear identification scheme based on fuzzy basis function expansion to adoptively compensate the parameter variations, i.e. rotor resistance, mutual and self inductance etc. An important feature of the proposed control scheme is to incorporate the sliding mode controller into the scheme to speed up convergence rate. Simulation tests show the robust behavior of the proposed controller in the presence of the parameter uncertainties of the machine.

• Journal of Engineering Education Research
• /
• v.25 no.5
• /
• pp.94-103
• /
• 2022

In this study, we examined the cases of online video classes conducted under the COVID-19 situation for 46 first-year students majoring in electrical engineering at a 3-year college in Gyeongnam. The research was carried out according to the course development process so that classes could be conducted efficiently, focusing on electromagnetism(1) course in the second semester of the first year. The online class consisted of uploading PPT recorded videos and lecture materials to the LMS and giving assignments. The contents of the study were in the scope of examining learners' perceptions through online learning contents, assignment submission, mutual feedback between instructors and learners, university-level lecture evaluation, and free opinions on online video-based electromagnetism(1) classes. As a result of the study, it was confirmed that online lecture review and problem-solving are particularly important for understanding lecture materials, and also given the nature of engineering subjects that require plenty of mathematical expressions, the detailed and immediate feedback provided by instructor enhances learners' class satisfaction and understanding. Based on these, the direction of online classes to be developed after the COVID-19 pandemic and teaching and learning methods suitable for the characteristics of subjects were discussed.

• Proceedings of the KIPE Conference
• /
• 1998.07a
• /
• pp.239-244
• /
• 1998

We propose a nonlinear feedback controller that can control the induction motors with high dynamic performance by means of decoupling of motor speed and rotor flux. A new recursive adaptation algorithm for rotor resistance which can be applied to our nonlinear feedback controller is also presented in this paper. Some simulation results show that the adaptation algorithm for rotor resistance is robust against the variation of stator resistance and mutual inductance. In addition, it is computationally simple and has small estimation errors.

• Proceedings of the KIPE Conference
• /
• 1998.10a
• /
• pp.23-28
• /
• 1998

We propose a nonlinear feedback controller that can control the induction motors with high dynamic performance by means of decoupling of motor speed and rotor flux. The nonlinear feedback controller needs the information on some motor parameters. Among them, rotor resistance varies greatly with machine temperature. A new recursive adaptation algorithm for rotor resistance which can be applied to our nonlinear feedback controller is also presented in this paper. The recursive adaptation algorithm makes the estimated value of rotor resistance track its real value. Some simulation results show that the adaptation algorithm for rotor resistance is robust against the variation of stator resistance and mutual inductance. In addition, it is computationally simple and has small estimation errors. To demonstrate the practical significance of our results, we present some experimental results.

• 제어로봇시스템학회:학술대회논문집
• /
• 2001.10a
• /
• pp.139.4-139
• /
• 2001

The thesis propose the sensorless vector control method that estimates the rotor speed using stator current. The estimated speed is used as feedback in a vector control system. The conventional MRAS structure has a problem the error output is decreasing as estimated speed error is increasing and the estimation performance is not robust when mutual inductance has been changed. In the proposed method, error output is proportional to estimated speed error. The described technique is less complex, robust to variations of mutual inductance. This new method can achieve much wider bandwidth speed control than that of the conventional MRAS structure.

• Convergence Security Journal
• /
• v.14 no.6_2
• /
• pp.63-72
• /
• 2014

The purpose of this study is to investigate the relationship between organizational culture, job characteristics and job continuance will among police officers. This study targets the police officers dispatched in the Seoul metropolitan area in 2012, and it uses judgment sampling method to analyze 187 samples. This study conducted the statistical analysis, including frequency analysis, factor analysis, reliability analysis and multiple regression analysis, by using SPSS WIN 18.0. The result is as follows. First, the organizational culture among police officers has effects on job characteristics. That is, the feedback increases as the organizational culture becomes more mutual development- or agreement-oriented, or as it becomes more hierarchical; on the other hand, the job importance increases as more hierarchical and rational a culture becomes. Also, self-determination increases as an organization becomes more mutual development- or agreement-oriented. Second, the organizational culture among police officers has effects on the job continuance will. That is, the expected satisfaction increases but intentional insincerity decreases as the organizational culture becomes more mutual development- or agreement-oriented. Also, risk-perceiving behavior increases as an organizational culture becomes more hierarchical. Third, police officers' job characteristics have effects on the job continuance will. That is, the feedback and job importance increases the expected satisfaction while reducing functional diversity. The feedback also reduces the contraction factor. The job importance increases intentional insincerity while reducing functional diversity. The functional diversity not only increase alternative expectation but also increases risk-perceiving factors.

• Journal of Mechanical Science and Technology
• /
• v.16 no.8
• /
• pp.1039-1052
• /
• 2002

This paper presents an application where a Fuzzy-Logic Controller (FLC) is used at a supervisory level to implement mutual coordination of the steering of the two front wheels of a motorcar. The two front wheels are steered by two independent discrete time state feedback controllers with a view to optimize the steering slip angles. The functions of the two controllers are tied together by way of a FLC. Because of the presence of unmodelled dynamics and disturbances acting on the two sides, it is difficult to achieve the desired performance using conventional control systems. This is the primary reason that FLC is emploged to solve the problem. The results show that the implemented system achieved desired coupling between the two independent systems and thereby reduces the difference between the two steered angles.

• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.6
• /
• pp.932-938
• /
• 2009

As a stringing troy wire is installed by manual operation, it is necessary to scheme the automatic system for stringing troy wire. To accomplish a task of this kind, in this paper an approach to designing controllers for the hybrid Position/Tension control of a stringing troy wire is presented. Position control system is designed based on equation of dc motor and motion equation of robot, it is controlled by feedback with a detected speed dc motor. Tension control system is designed based on equation of ac servomotor for generating torque and dynamic equation of a troy wire, it is controled by feedback with a detected tension. The control parameters is determined by simulation in independence operation of each system. To suppress a mutual interference that the disturbance occur in operating of two task at same time. Dynamic hybrid control is proposed by feed forward compensator with a disturbance accelerator and a step torque at start. The operation of proposed system is simulated and experimented, results is verified the utilities.