• Steel and Composite Structures
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• 제6권2호
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• pp.87-101
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• 2006

The deformation and dynamic behavior mechanism of submerged shell-like lattice structures with membranes are in principle of a non-conservative nature as circulatory system under hydrostatic pressure and disturbance forces of various types, existing in a marine environment. This paper deals with a characteristic analysis on quasi-periodic and chaotic behavior of a circular arch under follower forces with small disturbances. The stability region chart of the disturbed equilibrium in an excitation field was calculated numerically. Then, the periodic and chaotic behaviors of a circular arch were investigated by executing the time histories of motion, power spectrum, phase plane portraits and the Poincare section. According to the results of these studies, the state of a dynamic aspect scenario of a circular arch could be shifted from one of quasi-oscillatory motion to one of chaotic motion. Moreover, the correlation dimension of fractal dynamics was calculated corresponding to stochastic behaviors of a circular arch. This research indicates the possibility of making use of the correlation dimension as a stability index.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.219-222
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• 1997

Due to the unpredictability and irregularity, the behaviors of chaotic systems are considered as undesirable phenomena to be avoided or controlled. Thus in this paper, to control systems showing chaotic behaviors, a direct adaptive control method using a radial basis function network (RBFN) as an excellent alternative of multi-layered feed-forward networks is presented. Compared with an indirect scheme, a direct one does not need the estimation of the controlled process and gives fast control effects. Through simulations on the two representative continuous-time chaotic systems, Duffing and Lorenz systems, validity of the proposed control scheme is shown.

• 한국지능시스템학회논문지
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• 제8권4호
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• pp.8-17
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• 1998

자율 이동 로봇군은 분산된 자기 조직의 동일 규칙하에 주어진 과제를 수행하는로봇의 집단을 말한다. 본 논문에서는 협조 행동을 위한 수행 과제로서 등간격 원을 형성하게 하였다. 여기서, 이를 수행하기 위한 알고리듬을 고안하였고 여기에 퍼지 시스템을 사용하여 알고리듬을 보완하였다. 이 알고리듬을 가지고 사뮬레이션을 통해 다양한 협조 행동 양식이 나타남을 알수 있으며 특히 이동 속도롤 증가 시켰을 때 카오틱 현상이 일어남을 알 수 있다. 그리고 리아프노프 지수를 계산하여 이 카오스 현상의 특성을 증명하였다.

• 센서학회지
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• 제21권5호
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• pp.389-393
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• 2012

A chaotic oscillator with light controllability was designed. The proposed chaotic oscillator consists of a photo sensor, two phase clock driven MOS switches, nonlinear function blocks for chaotic signal generation. SPICE circuit analysis using a 0.35 um CMOS process parameters was performed for its chaotic dynamics. And we confirmed that chaotic behaviors of the circuit can be controlled according to light intensity. By SPICE simulation, chaotic dynamics by time waveforms, frequency analysis was analyzed. SPICE results showed that proposed circuit can make various light-controlled chaotic signals.

• 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.

• 한국광학회:학술대회논문집
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• 한국광학회 1989년도 제4회 파동 및 레이저 학술발표회 4th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.73-75
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• 1989

Chaotic states of a low-frequency modulating C.W .Co2 laser beam is observed. The output behaviors appear quasi-periodicity and chaotic states when the laser beam is modulated from 100Hz to 1000Hz by using an intracavity chopper. And the output characteristics of the laser beam show a route to chaos as increasing input power when the modulation speed is 500Hz.

• 디지털콘텐츠학회 논문지
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• 제18권1호
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• pp.217-224
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• 2017

최근에 카오스 이론을 사회과학의 한 분야의 사랑 모델에 적용하고자 하는 노력을 지속하고 있다. 로미오와 줄리엣으로 표현하는 미분 방정식에서 카오스 거동을 만들기 위해서 외력을 인가한다. 그러나 이 외력은 사람의 감정을 정확하게 표현하지 못하는 단점을 가진다. 본 논문에서는 이러한 단점을 해결하기 위하여, 로미오와 줄리엣의 사랑모델에서 외력을 사람의 말이나 행동에 가장 유사한 형태로 제공하기 위해 퍼지 소속 함수를 도입하고 이를 삼각 퍼지 소속 함수를 제시하였다. 또한 제시된 퍼지 소속 함수를 가진 로미오와 줄리엣의 사랑모델에서 카오스 거동을 확인하기 위하여, 시계열과 위상공간을 이용하였으며 이를 통하여 카오스 거동의 존재를 확인한다.

• Journal of the Korean Data and Information Science Society
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• 제28권6호
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• pp.1565-1571
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• 2017

The standard logistic map is an iterative function, which forms a discrete-time dynamic system. The chaotic logistic map is a kind of ergodic map defined over the unit interval. In this paper we study the limiting behaviors on the several processes induced by the chaotic logistic map. We derive the law of large numbers for the process induced by the chaotic logistic map. We also derive the uniform law of large numbers for this process. When deriving the uniform law of large numbers, we study the role of bracketing of the indexed class of functions associated with the process. Then we apply the idea of DeHardt (1971) associated with the bracketing method to the process induced by the logistic map. We finally illustrate an application to Monte Carlo integration.

• 대한기계학회논문집
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• 제19권2호
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• pp.495-508
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• 1995

The self-excited vibrations of airfoil is related to the classical flutter problems, and it has been studied as a system with linear stiffness and small damping. However, since the actual aircraft wing and the many mechanical elements of airfoil type have various design variables and parameters, some of these could have strong nonlinearities, and the nonlinearities could be unexpectedly strong as the parameters vary. This abrupt chaotic behavior undergoes ordered routes, and the behaviors after these routes are uncontrollable and unexpectable since it is extremely sensitive to initial conditions. In order to study the chaotic behavior of the system, three parameters are considered, i.e., free-stream velocity, elastic distance and zero-lift angle. If the chaotic parameter region can be identified from the mathematically modeled nonlinear differential equation system, the designs which avoid chaotic regions could be suggested. In this study, by using recently developed dynamically system methods, and chaotic regions on the parameter plane will be found and the safe design variables will be suggested.

• International Journal of Automotive Technology
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• 제8권4호
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• pp.467-476
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• 2007

This work verifies the chaotic motion of a steer-by-wire vehicle dynamic system, and then elucidates an application of dither smoothing to control the chaos of a vehicle model. The largest Lyapunov exponent is estimated from the synchronization to identify periodic and chaotic motions. Then, a bifurcation diagram reveals complex nonlinear behaviors over a range of parameter values. Finally, a method for controlling a chaotic vehicle dynamic system is proposed. This method involves applying another external input, called a dither signal, to the system. The designed controller is demonstrated to work quite well for nonlinear systems in achieving robust stability and protecting the vehicle from slip or spin. Some simulation results are presented to establish the feasibility of the proposed method.