• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.263-263
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• 2000

Electromagnetic Suspension(EMS) System produces no noise, friction and heat through non-contacting operation Therefore, the applicable device using EMS system has a lot of attraction in case of the high-speed and non-contacting transmission EMS with nonlinear properties requires a precise airgap position control and stable kinematics characteristics under the disturbances, In this study, the nonlinear system was linearized by a Nonlinear Feedback Lineariztion(NFL) method. The NFL method requires that the modelling should be exact, and the state variables should be measured and a rapidly operating controller be necessary on account of a heavy data calculating In the experiments. the ideal control characteristics of the NFL was acquired through simulation at first. then the characteristics of the actual system were compared with those of simulation. In addition, the results by NFL were examined and analysed considering the characteristics of the PID control. The Control by NFL shows much stable control characteristics than the PID control. Whereas, the steady state errors occur for various disturbances. hence a robust control design is remained for a further study.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.6
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• pp.192-201
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• 1997

The feedback control scheme of the pressure control system of the rear wheel steering gear which has relatively large volume and sprung load was built up in order to improve th response characteristic of the system. The control algorithm chosen was a feedback compensator joined by a feedfoward compensator and the model matching method was used in the process of control system design. The structures and properties of the reference models were inspected and the parameters of the controller were decided. The improvement of the response characteristic of the pressure control valve by means of the feedback control is affirmed. Particularly, when the order of the system model is higher than the 2nd order, the effectiveness of the feedback control on the improvement of the response characteristic of the valve is distinct. And the convenience of the model matching method is the process of control system design is confirmed as well.

• Journal of Power Electronics
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• v.9 no.4
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• pp.604-611
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• 2009

A dP/dV feedback-controlled MPPT (Maximum Power Point Tracking) method for photovoltaic power systems using II-SEPIC (Isolated Inverse-SEPIC; Single Ended Primary Inductance Converter) is presented and a current-mode dP/dV feedback-controlled MPPT method is devised to apply for the PV power converter system. A control strategy for the current-mode dP/dV feedback control system is developed in this paper and the proposed MPPT shows relatively satisfactory dynamics against rapidly changing insolation conditions. In order to verify the validity and effectiveness of the proposed method, simulations and experiments of the PV power system using II-SEPlC converter are performed. These simulation and experiment results show that the proposed method enables the PV power system to extract maximum power from the photovoltaic module against the solar insolation variation.

• 제어로봇시스템학회:학술대회논문집
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• 2005.06a
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• pp.1632-1636
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• 2005

This paper presents synchronization of two identical Modified Chua's circuits using two strategies of error feedback coupling. In the first method the synchronization is achieved by linear unidirectional and in the second one by linear bidirectional error feedback coupling. Both proposed methods can make the states of the Modified Chua's circuits globally asymptotically synchronized. Numerical results are provided to show the effectiveness of the proposed approaches and to compare them together based on different criteria.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.202-202
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• 2000

In this paper, the synchronous generator model which is derived from the swing equation and the Park's equation is transformed to an adequate form for feedback linearization. And the single controller is designed in order to play the role of both PSS and AVR. The result of the simulations shows that the stability of the system is guaranteed in the wide range of operating points.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2378-2387
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• 2017

Violinists learn to make better sounds by hearing and evaluating their own playing though numerous practice. This study proposes a new method of auditory feedback, which mimics this violinists' step and verifies its efficiency using experiments. Making the desired sound quality of a violin is difficult without auditory feedback even though an expert violinist plays. An algorithm for controlling a robot arm of violin playing robot is determined based on correlations with bowing speed, bowing force, and sound point that determine the sound quality of a violin. The bowing speed is estimated by the control command of the robot arm, where the bowing force and the sound point are recognized by using a two-axis load cell and a photo interrupter, respectively. To improve the sound quality of a violin playing robot, the sounds information is obtained by auditory feedback system applied Short Time Fourier Transform (STFT) to the sounds from a violin. This study suggests Gaussian-Harmonic-Quality (GHQ) uses sounds' clarity, accuracy, and harmonic structure in order to decide sound quality, objectively. Through the experiments, the auditory feedback system improved the performance quality by the robot accordingly, changing the bowing speed, bowing force, and sound point and determining the quality of robot sounds by GHQ sound quality evaluation system.

• KIPS Transactions on Software and Data Engineering
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• v.6 no.7
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• pp.361-370
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• 2017

This paper proposes the architecture of test case generator that can generate test cases, considering feedback signals from subsystems controlled by an embedded system. In general, a closed system decides the next test input to its subsystem under its control referencing feedback signals from its subsystem. In such systems, it is hard to use the typical test cases generated without referencing feedback. The architecture proposed in this paper re-produces test cases in real time using feedback signals. The architecture is implemented and its effectiveness is verified through experimenting a demo system.

• The Journal of Korean Association of Computer Education
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• v.7 no.1
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• pp.89-96
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• 2004

Formative evaluation is an evaluation activity performed in the process of teaching and learning. The general purpose of formative evaluation is to provide the feedback and correct identified problems in the process of teaching and learning. In this paper, we propose a system which provides each student with individualized feedback in formative evaluation. The evaluation questionnaire in the system are produced on the basis of the section criteria such as knowledge, comprehension, and application. The evaluation result is categorized and evaluated according to the given criteria. Then different feedback is provided for each student advising where he or she should make up for weak areas. Moreover our system offers instructors the itemized correct answer ratio data as well as sets of individualized feedback delivered to students. It gives an additional benefit to ensure the improvement of teaching methods.

• ETRI Journal
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• v.38 no.2
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• pp.280-290
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• 2016

To implement high-order multiuser multiple input and multiple output (MU-MIMO) for massive MIMO systems, there must be a feedback scheme that can warrant its performance with a limited signaling overhead. The interference-to-noise ratio can be a basis for a novel form of Codebook (CB)-based MU-MIMO feedback scheme. The objective of this paper is to verify such a scheme's performance under a practical system configuration with a 3D channel model in various radio environments. We evaluate the performance of various CB-based feedback schemes with different types of overhead reduction approaches, providing an experimental ground with which to optimize a CB-based MU-MIMO feedback scheme while identifying the design constraints for a massive MIMO system.

• International Journal of Control, Automation, and Systems
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• v.3 no.1
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• pp.109-116
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• 2005

The design of reconfiguring a class of second-order dynamic systems via proportional plus derivative (P-D) feedback is considered. The aim is to resynthesize a P-D feedback controller such that the eigenvalues of the reconfigured closed-loop system can completely recover those of the original close-loop system, and make the corresponding eigenvectors of the former as close to those of the latter as possible. Based on a parametric result of P-D feedback eigenstructure assignment in second-order dynamic systems, parametric expressions for all the P-D feedback gains and all the closed-loop eigenvector matrices are established and a parametric algorithm for this reconfiguration design is proposed. The parametric algorithm offers all the degrees of design freedom, which can be further utilized to satisfy some additional performances in control system designs. This algorithm involves manipulations only on the original second-order system matrices, thus it is simple and convenient to use. An illustrative example and the simulation results show the simplicity and effect of the proposed parametric method.