• Proceedings of the KIEE Conference
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• 1998.07b
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• pp.486-489
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• 1998

In this paper, we introduced the neural network to reduce force ripple of current controller for a linear pulse motor. In general, conventional position controllers of linear pulse motor disregard the modeling error and load variations, which cause inaccuracy in position control. The proposed current controller based on neural network teaming modifies the current commands in order to reduce force ripple due to these factors. The experiment results show that the proposed controller works efficiently for accurate position control of linear pulse motor.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2818-2820
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• 2002

In this paper, we design neurofuzzy networks architecture by means of linear fuzzy inference. The proposed neurofuzzy networks are equivalent to linear fuzzy rules, and the structure of these networks is composed of two main substructures, namely premise part and consequence part. The premise part of neurofuzzy networks use fuzzy space partitioning in terms of all variables for considering correlation between input variables. The consequence part is networks constituted as first-order linear form. The consequence part of neurofuzzy networks in general structure(for instance ANFIS networks) consists of nodes with a function that is a linear combination of input variables. But that of the proposed neurofuzzy networks consists of not nodes but networks that are constructed by connection weight and itself correspond to a linear combination of input variables functionally. The connection weights in consequence part are learned by back-propagation algorithm. For the evaluation of proposed neurofuzzy networks. The experimental results include a well-known NASA dataset concerning software cost estimation.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10a
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• pp.48-51
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• 1996

This note considers the $H^{\infty}$ controller design problem for linear systems with time-varying delays in states. We obtain sufficient conditions for the existence of k-th order $H^{\infty}$ controllers in terms of three linear matrix ineualities(LMIs). These sufficient conditions are dependent on the maximum value of the time derivative of time-varying delay. Furthermore, we briefly explain how to construct such controllers from the positive definite solutions of their LMIs and give an example.e.

• ETRI Journal
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• v.30 no.1
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• pp.170-172
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• 2008

A substitution box (S-box) plays a central role in cryptographic algorithms. In this paper, an efficient method for designing S-boxes based on chaotic maps is proposed. The proposed method is based on the mixing property of piecewise linear chaotic maps. The S-box so constructed has very low differential and linear approximation probabilities. The proposed S-box is more secure against differential and linear cryptanalysis compared to recently proposed chaotic S-boxes.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.05b
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• pp.279-282
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• 2000

We have been designed and fabricated a bi-directional ultrasonic linear motor using piezoelectric ceramics. With the finite element method, we design and verify validity of the structure, and determine its optimal structure, size of design variables, material and boundary conditions for proper generation of the ultrasonic waves. Based on the design, a prototype of the ultrasonic linear motor has been fabricated and characterized, which thereby proves practical applicability of this new motor.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.11
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• pp.1-8
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• 1997

In this paper, we propose a new method for the improvement of linearizing and adaptive convergence charateristics of the feedforward linear power amplifier. In this circuit, errors at the signal cancellation stage can be compensated at the error cancellation stage and the overall linearizaton and adaptation characteristics of the linear amplifier are improved. The broadband characteristics and linearizing capability are improved without increasing the complexity of circuits and the signal processing structure.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1999.11a
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• pp.300-302
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• 1999

The standing waves of the fourth bending mode of vibration and first longitudinal mode of vibrator were utilized to construct a ultrasonic linear motor. The geometrical dimensions of the vibrator were determined by Euler-Bernoulli theoty. FEM(finite element method) employed to calculate the vibration mode of the metal-piezoceramic composite thin plate vibrator. ANSYS was used to design positions of the projections and calculate displacement of vibrator.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.13 no.12
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• pp.1025-1031
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• 2000

An ultrasonic linear motors consist of a slider and an ultrasonic vibrator which generates an elliptical oscillations. The ultrasonic linear motors mainly consist of an ultrasonic vibrator which generates elliptical oscillations. The ultrasonic linear motor fabricated in this paper was the use of the 1st longitudinal(L1) and 4th bending vibrations(B4). In order to low driving voltage and improve the life time of the ultrasonic motor, we used stacked piezoceramics. Stacked piezoceramics are adhered to aluminum elastic material. The finite element method was used to optimize dimension of ultrasonic vibrator and direction of vibratory displacement. As a result of estimating the characteristics of the ultrasonic linear motor, no-load velocity was 0.204[m/s] when applied voltage was 70[ $V_{rms}$] in resonance frequency.y.

• 제어로봇시스템학회:학술대회논문집
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• 1995.10a
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• pp.162-165
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• 1995

For an accurate on-line measurement of the ship's attitude the paper develops an intelligent sensing system which uses one servo-type accelerometer and two servo-type inclinometers appropriately located on the ship. By considering the dynamics of the servo-controlled rigid pendulums of the inclinometers, linear equations for the rolling and pitching of the ship are derived separately from each other. Moreover, one accelerometer is used for extracting the heaving signal. Through the introduction of linear dynamic models and the linear observation equations for the heaving, rolling and pitching, the on-line measurement of the three signals can be reduced to the state estimation of the linear dynamic systems. A bank of Kalman filters is adaptively used to achieve the on-line accurate state estimation and to overcome changes in parameters in the linear dynamic models.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.11a
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• pp.204-207
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• 2000

An ultrasonic linear motor was composed of a slider and a stator vibrator including piezoelectric material and elastic material. The ultrasonic linear motors mainly consist of an ultrasonic vibrator which generates elliptical oscillations. L$_1$-B$_4$ ultrasonic linear motor use longitudinal and bending multi-vibration. In order to low driving voltage and improve the life time of the ultrasonic oscillator, we used stacked piezoceramics. Stacked piezoceramics are adhered to aluminum elastic material. The finite element method was used to optimize dimension of ultrasonic vibrator and direction of vibratory displacement. As a result of estimating the characteristics of the ultrasonic linear motor, no-load velocity was 2.04[m/s] when applied voltage was 70[V$\sub$rms/] in resonance frequency.