• Journal of the Korean Data and Information Science Society
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• 제22권5호
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• pp.903-910
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• 2011

어류의 성장함수로는 동화작용과 이화작용의 차이가 성장을 결정하는 형태의 곡선이 사용 된다. 대부분의 어류는 일 년에 정해진 기간에 한번 산란하는 형태를 갖는다. 이러한 어류를 일시적 산란 어류라고 하고 이와는 다르게 일 년 동안 영양 상태에 따라 계속적으로 산란하는 멸치 등의 어류를 연속산란 어류라고 한다. 본 논문에서는 일시적 산란 어류에 비교하여 산란 시기가 성장에 영향을 많이 주는 연속 산란 어류의 성장곡선을 산란시기의 수온 함수로 성장식을 유도하였다.

• 전기전자학회논문지
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• 제2권2호
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• pp.263-269
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• 1998

릴레이 대신 포화함수를 이용하여 선형 플랜트의 극한 이득과 주기를 결정하였다. 포화함수를 사용함으로서 플랜트의 고주파 성분을 감소 시켜 묘사함수 사용에 의한 극한이득과 주기 결정의 정확도를 증가시켰다. 또한 적절한 포화함수를 사용할 수 있는 간단한 절차를 기술하였으며 진동이 발생하지 않는 플랜트에 대해서 지연요소를 이용한 자동동조 방법을 제시하였다.

• 제어로봇시스템학회논문지
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• 제21권3호
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• pp.237-242
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• 2015

This paper presents a method to enhance tracking performance of an input-constrained bilinear system using MPC (Model Predictive Control) when a feasible tracking control is known. Since the error dynamics induced by the known tracking control is asymptotically stable, there exists a Lyapunov function for the stable error dynamics. By defining a cost function including the Lyapunov function and describing tracking performance, an MPC law is derived. In simulation, the performance of the proposed MPC law is demonstrated by applying it to a converter model.

• 충청수학회지
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• 제25권3호
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• pp.475-489
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• 2012

A plateau in a Motzkin path is a sequence of three steps: an up step, a horizontal step, then a down step. We find three different forms for the bivariate generating function for plateaus in Motzkin paths, then generalize to longer plateaus. We conclude by describing a further generalization: a continued fraction form from which one can easily derive new multivariate generating functions for various kinds of path statistics. Several examples of generating functions are given using this technique.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2003년도 The Korea-Japan Joint Symposium
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• pp.114-114
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• 2003

Fiber bundles output from a draft operation have linear density irregularity. This study is dealing with modeling the dynamics of fiber bundle during roll drafting based on continuity, momentum balance, and a constitutive assumption. The simulation results from this model are compared with experimental results and analyzed by applying the concept of the Describing Function(DF). It can be confirmed that the simulation results agree well with experiments in a steady state, if the model parameters are good adjusted.

• Journal of Electrical Engineering and Technology
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• 제10권4호
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• pp.1843-1850
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• 2015

Controlling nonlinear systems with linear feedback control methods can lead to chaotic behaviors. Order increase in system dynamics due to integral control and control parameter variations in PID controlled nonlinear systems are studied for possible chaos regions in the closed-loop system dynamics. The Lur’e form of the feedback systems are analyzed with Routh’s stability criterion and describing function analysis for chaos prediction. Several novel chaotic systems are generated from second-order nonlinear systems including the simplest continuous-time chaotic system. Analytical and numerical results are provided to verify the existence of the chaotic dynamics.

• 대한수학회논문집
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• 제10권1호
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• pp.123-131
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• 1995

The notion of our non-associative algebra is obtained from the Lotka-Volterra system of differential equation describing competitiion between animals or vegetals species and also in the kinetic theory of gasses. For the structure of an algebra, the existence of idempotents is of particular interest. But also from the biological aspect the existence of such elements is of interest because the equilibria of a population which can be described by an algebra correspond to idempotents of this algebra. Thus we present some properties of the general natures for a Lotka-Volterra algebra associated to a weight function and idempotents elements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1989년도 추계학술대회 논문집 학회본부
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• pp.351-354
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• 1989

In a speed_controlled system with cascade control which shows an optimal performance in the linear case, limit cycles can occur due to backlash. The various effects observed can be explained with the aid of the describing function. With a first-order load torque observer these limit cycles can be avoided. Moreover the dynamic performance improves considerably and the range of application of cascade control is extended.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1991년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 22-24 Oct. 1991
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• pp.299-304
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• 1991

A novel approach based on a nonlinear compensator is proposed to prevent 'windup', which is caused by the saturation of the actuator and the integration action of the controller. The anti-windup compensator is located between the conventional linear controller, designed neglecting the saturation, and the actuator. It was proven based on the describing function method that, if the closed loop control systems are stable assuming no saturation, then there exist a range of compensator gain which prevents any limit-cycle and hence, guarantees the system stability. The computer simulation results show that the compensator proposed in the manuscript can eliminate unstable limit cycle and improve the transient response.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1989년도 한국자동제어학술회의논문집; Seoul, Korea; 27-28 Oct. 1989
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• pp.1091-1096
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• 1989

All mechanical systems have saturation nonlinearity in actuators or in final control elements. When controllers have integral action, reset windup can cause instability as well as make the system performance unsatisfactory. In this study, an intelligent limiter which needs no tuning of parameters is tested with the PDF controller used for control of a second order plant. This paper presents analysis of the stability of the system using the describing function method and the Nyquist stability theorem. The improvement of the system performance by the limiter is illustrated by computer simulations.