• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.7
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• pp.16-23
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• 2018

Chaos is one of the most significant topics in nonlinear science, and has been intensively studied since the Lorenz system was introduced. One characteristic of a chaotic system is that the signals produced by it do not synchronize with any other system. It therefore seems impossible for two chaotic systems to synchronize with each other, but if the two systems exchange information in just the right way, they can synchronize. This paper addresses the problem of synchronization in a modified Lorenz chaotic system based on active control, sliding mode control, and the Lyapunov stability theory. The considered synchronization scheme consists of identical drive and response generalized systems coupled with linear state error variables. For this, a brief overview of the modified Lorenz chaotic system is given. Then, control rules are derived for chaos synchronization via active control and slide mode control theory, with a strategy for solving the chattering problem. The asymptotic stability of the overall feedback system is established using the Lyapunov stability theory. A set of computer simulation works is presented graphically to confirm the validity of the proposed method.

• Journal of Electrical Engineering and Technology
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• v.9 no.5
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• pp.1686-1693
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• 2014

In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

• Korean Institute of Interior Design Journal
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• v.13 no.2
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• pp.80-90
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• 2004

Scientism is a kind of paradigm since the birth of Modernism. Architectural design was also effected from scientism in the 1st Machine age, and being effected still In the End Machine age. But many architects in the 2nd Machine age express scientism in architectural design as a "science for kick" as SF. The design of Rem Koolhaas follows the line of Modernism which was effected from scientism in many ways. However he shows modified machine aesthetics as SF pataphysics mixed with literary imagination, and now shows new science paradigm in post-modern age. He expresses many new science theory like indeterminacy theory, chaos, catastrophe theory in his works. And those are expressed as indeterminate program that proceeds in non-linear way, rhizome in space, order out of chaos, topological metamorphosis as a catastrophe. This study analyzes the expression of scientism in architectural design of Rem Koolhaas since 1970s.nce 1970s.

• Proceedings of the KIEE Conference
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• 1997.11a
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• pp.228-230
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• 1997

Recently, as power systems become large and complicated, chaos theory has been introduced to analyze their nonlinear characteristics. In this paper, voltage collapse phenomenon is more accurately analyzed using bifurcation theory of chaos. Chaotic behaviors has been observed in computer simulation for a simple power system over a range of loading conditions. Besides existence of voltage collapse point in critical value, operation of power system in Hopf window can be the cause of voltage collapse.

• Archives of design research
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• v.13
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• pp.235-255
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• 1996

The world-view of a period or a society refers to the way it conceives of the order and governing principles of the universe. The ad and outcome of the crealive process of a designer reflect his or her world-view or value system. Contemporary students of design seem to find the traditional approach to art based upon the Euclidean logic rather redudive and confining and are trying to develop a new way of thinking and methodology, a new frame of reference. In this study, I am offering the chaos- and fractal theory, concepts drawn from science, as a new anchoring point for design. This approach makes use of the concept of chaos as the basis of a new, open system that enables a designer to find and generate numerous visual possibilities immanent in chaos. Likewise. fractal geometry is offering new concepts and vocabularies for the study of physical universe and design thinking, as well as bridging the gap between science and art. The number of structural possibilities fractal theory generates for environmental design seems to be virtually unlimiLl'd. In fine. this study places a great emphasis on the new approaches t() the environment we inhabit. which I hope will contribute to generating a greater number of creative possibililil:s for environmental design.

• Journal of Korean Society of Transportation
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• v.17 no.2
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• pp.115-126
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• 1999

Past nears many Studies have been described for present state and forecasted for the future phenomena in various areas. Many theories and methodologies in transportation have been developed and applied by researchers and planners. On the other hand, many theories and methodologies had disappeared caused by their critical limitations. One of this cause that was discovered of the Chaos in traffic flows. The occurrence of Chaos in traffic flows has affected to the traffic volume and decreased significancy of a simulation result of a specific traffic flow. According to this fact, long-term forecast of traffic flow is difficult, moreover a butterfly effect impedes development and establishment of transportation model. A methodology to solve Chaos character in traffic flow can be able to provide more effective transport planning. This study tackles to enhance and revise the existing theories for the traffic flow applying Chaos theory to estimating travel time.

• The Magazine of the IEIE
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• v.20 no.3
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• pp.43-52
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• 1993

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 1999.12a
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• pp.674-684
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• 1999

• Speech Sciences
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• v.3
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• pp.148-155
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• 1998

As an application of dimensional analysis in the theory of chaos and fractals, we studied and estimated the information dimension for various phonemes. By constructing phase-space vectors from the time-series speech signals, we calculated the natural measure and the Shannon's information from the trajectories. The information dimension was finally obtained as the slope of the plot of the information versus space division order. The information dimension showed that it is so sensitive to the waveform and time delay. By averaging over frames for various phonemes, we found the information dimension ranges from 1.2 to 1.4.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.05a
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• pp.187-190
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• 2000

Chua's circuit is a simple electronic network which exhibits a variety of bifurcation and attractors. The circuit consists of two capacitors, an inductor, a linear resistor, and a nonlinear resistor. In this paper, a transmitter and a receiver using two identical Chua's circuits are proposed and synchronizations of a power line are investigated. Since the synchronization of the power line system is impossible by coupled synchronization, theory having both the drive-response and the coupled synchronization is proposed. As a result, the chaos synchronization has delay characteristics in the power line transmission system caused by the line parameters L and C.