자기동조 레귤레이터의 비선형성 보상을 위한 새로운 신경회로망 제어방식

엄기환,이용구,정성부,김진식 東國大學校 1996 東國論叢 Vol.35 No.-

In this paper, we propose a new controller design method that can get good control performance and reduce computation by loosing to small step size of conventional STR, owe to adding a neural network controller in STR with parallel for compensating for STR's nonlinearity. Through having tested the validity of the proposed controller by one link manipulator simulation and experiment, we compare with control performance for convention-al STR

EM Simulator를 이용한 Microstrip Interdigital Bandpass Filter 설계

엄기환,양승인 崇實大學校 2000 論文集 Vol.30 No.1

This paper presents how to design an Interdigital Bandpass Filter that often can be used in microwave band. This filter, made of a substrate(alumina) with □□ =9.8, h=1.27㎜, and t=0.035㎜, has a 400MHz bandwidth centered at 2GHz and 0.2dB ripple. The Interdigital Bandpass Filter is analyzed using the full-wave electromagnetic solver EM Sight in Applied Wave Research's Microwave Office 2000. The concept of tapping is applied to the filter's end section for the small size.

LUR'E 판별법과 Tzypkin 판별법의 유도

엄기환,박장환,이용구 동국대학교 산업기술연구원 1995 산업기술논문집 Vol.6 No.-

Lur'e 판별법으로부터 비선형소자 포화를 갖는 이산제어시스템의 안정도를 위한 Lyapunov 함수를 구성하고 이를 안정도 판별에 활용했다. 연속시스템에서의 Lur'e 판별법을 근거로 Popov 판별식이 유도되어지는 것과 같이, 이산 제어 시스템에서는 비선형소자 포화를 이산화함으로써 Zypkin 판별법이 유도되어 질 수 있었다. 시간영역과 주파수영역 사이의 안정도관계는 Lyapunov 함수의 존재를 근거로 하여, Kalman-Szego¨ 보조정리와 Zypkin 판별법을 유도하였다. In this paper, it is shown that the construction and application of Lyapunov-function for stability of non-linear discrete control system within on-linearity "saturation" from Lur'e-Criterion. The derivation of Popov-criterion is based on the Lur'e-criterion. In discrete control system, the derivation of Tzypkin-criterion is possible to discrization non-linearity element "saturation". Kalman-Szego¨-lemma and Tzypkin-criterion which the stability relationship between frequency domain and time domain representation, is derived based on the existence of Lyapunov-function.

역전파 신경회로망을 이용한 자기동조 적응제어

엄기환,손동설,박장환,이용구 동국대학교 산업기술연구원 1995 산업기술논문집 Vol.6 No.-

역전파 신경회로망을 추정기로 이용한 자기동조 적응제어방식을 제안하였다. 제안한 방식은 역전파 신경회로망을 이용하여 시스템함수를 추정하고 추정된 함수를 제어기에서 이용하는 자기동조 적응제어 기법이다. 제안한 방식의 유용성을 확인하기 위하여 가동코일형 선형 직류전동기를 제어대상으로 기존의 반복 최소 자승법을 이용한 자기동조 적응제어방식과 시뮬레이션 및 실험을 통하여 추종 특성을 비교 검토하였다. This paper proposes the self-tuning adaptive control method with back-propagation neural network using a identifier. A proposed method is self-tuning adaptive control method that estimates system functions using back-propagation neural network and estimated function is used to controller. In order to verify the usefulness of proposed method, tracking control characteristics are compared the general self-tuning adaptive control method using R.L.S by simulation and experiments.

컴퓨터 플로트에 의한 코클리아의 기저막속도 진폭 및 위상특성

嚴基煥 동국대학교 대학원 1985 大學院硏究論集-東國大學校 大學院 Vol.15 No.-

This study attempts the velocity characteristics of basilar mambrane in cochlea which performs the important function of hearing process. The velocity characteristics was obtained about 1-dimensional, 2-dimensional and 3-dimensional models by computer plot. The results obtained are as follows: 1) In the magnitude characteristics, the velocity gradually increases from the stapes, shows the maximum magnitude, and then rapidly decreases to the helicotrema. 2) In terms of phase characteristics, the velocity gradually decreases from the stapes and then rapidly decreases over the resonance toward helicotrema. 3) The characteristics of 3-dimensional model is located 1-and 2-dimensional models in the velocity magnitude and phase characteristics and the pattern of 2-dimensional model shows the different features from the 1-dimensional and 3-dimensional rectangular block model.

DSP를 이용한 간단한 Controller Board의 설계

嚴基煥,李鎔求 東國大學校 1994 東國論叢 Vol.33 No.-

This paper deals with a design of a DSP Board for solving real-time digital control problems. A DSP Board is composed of TMS320C31, AD1678, AD565A, and 8255A. A Designed DSP Board is suitable for accuracy control and is easy to make a control systems. A DSP Board is fabricated, which is demonstrated by the speed and position control of a DC Servo Motor using the Self-Tuning control algorithm.

Kalman-Szego-보조정리의 응용에 의한 제한된 제어입력을 위한 보상기 설계

박장환,이용구,엄기환 동국대학교 자연과학연구원 1995 자연과학연구 논문집 Vol.15 No.-

In this paper a method for design in order to use control input due to the saturation is proposed. This is done by designing a linear controller with the good property for reference input and control output without considering saturation or partially considering the saturation and is done by setting up a compensation loop which compensates for the lost portion of control input due to saturation. The Lyapunov function constructed by using the Kalman-Szego-Lemma was guaranteed for the stability problem arising due to the nonlinerarity of a compensation loop when a compensator is designed. Also, it is shown that this Lyapunov function was satisfied for Riccati equation.

경정맥 신우 조영술에서 검사 시간에 대한 연구

이선엽,엄기환 동국대학교 산업기술연구원 2007 산업기술논문집 Vol.16 No.2

Acute pyelonephritis is one of the most common causes of unexplained fever in children. It may lead to the development of progressive renal damage. However, the detection of acute pyelonephritis can be difficult, especially in infants. The objective of this study was to evaluate the diagnostic value of various lab tests and imaging studies for acute renal parenchymal changes in children with APN. We correlated the clinical and laboratory manifestations of acute pyelonephritis with the Imaging studies. With development of medical appliances, these methods which are an ultrasonograph, Computer Tomography, Magnetic Resonance Image and Angiography are frequently used the test of the urinary organs, but Intravenous Pyelography(IVP) is the examine method which is basic and important. Although IVP is used frequently, IVP's schedule to examine the urinary organ test is not being. In this paper, make a trial of the examination method which take a photograph with three method in the different time, each image quality was compared and examined the best effect expose time.

전방향 신경회로망을 이용한 블록암호화 기법

정경권,엄기환 동국대학교 산업기술연구원 1998 산업기술논문집 Vol.11 No.-

본 논문에서는 전방향 신경회로망으로 암호 함수를 구성하는 블록 암호 알고리즘 방법을 제안한다. 제안한 방법은 블록 암호 알고리즘에서 사용되는 암호화 함수 전체를 전방향 신경회로망으로 대치하는 방법과, DES 암호 알고리즘에서 S-box를 전방향 신경회로망으로 대치하는 방법이다. 신경회로망의 가중치를 키로 사용하여 암호화 및 복호화를 수행한다. 신경회로망의 비선형적인 특성과 각각의 층을 구성하고 있는 뉴런간의 방대한 연결로 복잡한 구조를 가지고 있다. 또한 은닉층의 구성에 따라 여러 형태의 설계가 가능하다. In this paper, we propose a block cipher algorithms composing cipher function using feedforward neural network. The proposed methods are that cipher function used in the block cipher algorithm is totally replaced with feedforward neural network, and also, S-box is replaced with feedforward neural network in DES algorithm. The weight of neural network is used as a key to perform an encryption and decryption. It has complex structure due to its nonlinear characteristic and the enormous connections among neurons which organize layers respectively. Also, various design shapes are applicable by different structures of hidden layers.

GRBFNN을 이용한 직접 적응제어기 설계

이용구,엄기환 동국대학교 산업기술연구원 1997 산업기술논문집 Vol.9 No.-

본 논문에서는 비선형 동적시스템의 적응제어를 위해 Generalized Radial Basis Function Neural Network을 직접 제어기로 이용하는 새로운 설계방식을 제안한다. 제안된 제어방식의 장점은 신경회로망의 학습력으로 인해 미지의 비선형 시스템을 위한 제어기 설계가 간단한 데 있다. 제안된 제어방식의 제어성능의 우수함을 입증하기 위하여 단일링크 매니퓰레이터를 시스템으로 많은 시뮬레이션을 통하여 적응퍼지제어방식과의 특성을 비교한다. In this paper, a new scheme, directly using a Generalized Radial Basis Function Neural Network as a controller, is proposed for the adaptive control of a class of nonlinear dynamical systems. The advantage of the proposed control method is simple to design a controller for unknown nonlinear systems because of learning ability. In order to verify excellent control performances of the proposed control method, we compared with a adaptive fuzzy control method. through a lot of simulations with one link manipulator.