• Journal of the Korean Society of Visualization
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• v.9 no.1
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• pp.17-19
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• 2011

The bubble oscillations play an important role in ultrasonic cleaning processes. In the ultrasonic cleaning of semiconductor wafers, the cleaning process often damages micro/nano scale patterns while removing contaminant particles. However, the understanding of how patterns in semiconductor wafers are damaged during ultrasonic cleaning is far from complete yet. Here, we report the observations of the motion of bubbles that induce solid wall damage under 26 kHz continuous ultrasonic waves. We classified the motions into the four types, i.e. volume motion, shape motion, splitting or jetting motion and chaotic motion. Our experimental results show that bubble oscillations get unstable and nonlinear as the ultrasonic amplitude increases, which may exert a large stress on a solid surface raising the possibility of damaging microstructures.

• Proceedings of the KIEE Conference
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• 1997.07c
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• pp.897-899
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• 1997

The analysis of distribution line faults is essential to the proper protections of the power system. A high impedance fault does not make enough current to cause conventional protective devices. It is well known that undesirable operating conditions and certain types of faults on electric distribution feeders cannot be detected by using conventional protection system. This paper describes an algorithm using back-propagation neural network for pattern recognition and detection of high impedance faults. Fractal dimensions are estimated for distinction between random noise and chaotic behavior in the power system. The fractal dimension of the line current is also used as a indication of the high impedance fault.

• Steel and Composite Structures
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• v.22 no.6
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• pp.1261-1280
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• 2016

We study chaotic motion in a nonlinear laminated composite plate under subsonic fluid flow and a simultaneous external load in this paper. We derive equations of motion of the plate using the von-$K{\acute{a}}rm{\acute{a}}n^{\prime}s$ hypothesis and the Hamilton's principle. Galerkin's approach is adopted as the solution method. We then conduct a divergence analysis to obtain critical velocities of the transient flow. Melnikov's integral approach is used to find the critical parameters in which chaos takes place. Effects of different parameters including the aspect ratio, plate material and the ply angle in laminates on the critical flow speed are investigated. In a parametric study, we show that how the linear and nonlinear stiffness of the plate and the load frequency and amplitude would influence the chaotic behavior of the plate.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.4
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• pp.759-765
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• 2000

A diagnosis system that provides early warnings regarding machine malfunction is very important for rolling mill so as to avoid great losses resulting from unexpected shutdown of the production line. But it is very difficult to provide early warnings in rolling mill. Because dynamics of rolling mill is non-linear. This paper shows a chaotic behavior of vibration signal in rolling mill using embedding method. Not only phase plane and Poincare map are implemented but also FH and histogram of vibration signal in rolling mill is presented by embedding method.

• Journal of Korea Water Resources Association
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• v.41 no.9
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• pp.959-967
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• 2008

Disaggregation techniques are widely used to transform observed daily rainfall values into hourly ones, which serve as important inputs for flood forecasting purposes. However, an important limitation with most of the existing disaggregation techniques is that they treat the rainfall process as a realization of a stochastic process, thus raising questions on the lack of connection between the structure of the models on one hand and the underlying physics of the rainfall process on the other. The present study introduces a nonlinear deterministic (and specifically chaotic) framework to study the dynamic characteristics of rainfall distributions across different temporal scales (i.e. weights between scales), and thus the possibility of rainfall disaggregation. Rainfall data from the Seoul station (recorded by the Korea Meteorological Administration) are considered for the present investigation, and weights between only successively doubled resolutions (i.e., 24-hr to 12-hr, 12-hr to 6-hr, 6-hr to 3-hr) are analyzed. The correlation dimension method is employed to investigate the presence of chaotic behavior in the time series of weights, and a local approximation technique is employed for rainfall disaggregation. The results indicate the presence of chaotic behavior in the dynamics of weights between the successively doubled scales studied. The modeled (disaggregated) rainfall values are found to be in good agreement with the observed ones in their overall matching (e.g. correlation coefficient and low mean square error). While the general trend (rainfall amount and time of occurrence) is clearly captured, an underestimation of the maximum values are found.

• Journal of the Korean Institute of Intelligent Systems
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• v.25 no.4
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• pp.313-318
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• 2015

Recently, it is emphasized importance of family. The new husband and wife are created by caused marriage, they organize new family including wife's home and husband's home. As a result, they conflict or accomplish peace with new family. Such a researchers mainly have been studied in the social science side. Because there is no mathematical modeling which is one of the natural science, for family relationship, it is not provide to reveal the behavioral phenomena between families fundamentally. In this paper, one of the nonlinear research for social subject, we modify love model of Romeo and Juliet. Then we propose novel family relationship model for parent-in-law and daughter (or son)-in-law relation. We also confirm chaotic behavior or nonlinear behavior by time series and phase portrait.

• Journal of the Korean Institute of Intelligent Systems
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• v.26 no.1
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• pp.37-43
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• 2016

Recently, it is emphasized importance of family. The new family organize including husband and wife are created by caused marriage, they organize new family including wife's home and husband's home. As a result, they may experience about conflict or peace between new family and previous family. The research of family mainly have been studied in the social science side. However, because researchers of social science deals with linguistic emotion status, there is no mathematical modeling for family relationship. In this paper, one of the nonlinear research for social subject, we modify love model of Romeo and Juliet. Then we propose novel family relationship model for parent-in-law and daughter (or son)-in- law relation. We also confirm chaotic behavior or nonlinear behavior by time series and phase portrait.

• Korean Journal of Human Ecology
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• v.23 no.6
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• pp.1071-1087
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• 2014

The purpose of this study was to examine children's self-regulation and their problem behavior according to family interaction types. The subjects were 227 children and their mothers, and 14 teachers in Jeonbuk. To obtain family interaction types, self-questionnaires of FACES III are given to mothers. Also, self-questionnaires of children's self-regulation and problem behavior were given to teachers. The data were analyzed by computing t-test, ANOVA, Duncan post test, and multiple liner regression. The results were as follows. First, There was a difference in the children's self regulation and problem behavior, but not in family cohesion and adaptability, according to the children's sex, age, and family variables. Second, it was found that there was a difference in self-regulation and problem behavior according to family interaction types. It showed that self-regulation was higher and problem behavior was lower in the most 'enmeshed' families in cohesion and the most 'chaotic' families in adaptability. Third, considering the relative strength of each variable on children's problem behavior, it was shown that children's sex and age had the greatest influence on problem behavior, followed by self-regulation and family's cohesion. In conclusion, it is suggested that the efforts to improve family cohesion as a psychological environment should be made in order to increase the children's self regulation and to decrease the children's problem behavior.

• Journal of the Korean Institute of Intelligent Systems
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• v.24 no.3
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• pp.245-250
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• 2014

Addiction can be largely divided into two categories. One is called medium addiction in which medium itself causes an addiction. Another is called cause addiction that brings addiction through combination of sensitive self and latent personal action. The medium addiction involves addiction phenomena directly caused by illegal drugs, alcohol and various other chemicals. The cause addiction is dependent on personal sensitivities as a sensitive problem of personal and includes cyber addictions such as shopping, work, game, internet, TV, and gambling. In this paper we propose two-dimensional addiction model that are equivalent to using an R-L-C series circuit of Electrical circuit and a Spring-Damper-mass of mechanical system. We also organize a Duffing equation that is added a nonlinear term in the proposed two-dimensional addiction model. We represent periodic motion and chaotic motion as time series and phase portrait according to parameter's variation. We confirm that among parameters chaotic motion had addicted state and periodic motion caused by change in control coefficient had pre-addiction state.

• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1714-1724
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• 2003

Feedback strategies of a qualitative competitive game between two players can be designed such as to influence parameters of a mechanical system to induce chaotic behavior. The purpose is to reduce the options and effects of the opponent's strategy. We show it on a case with dynamics specified by a nonautonomous Duffing equation with the players represented by damping and external forcing, respectively. It seems however that the conclusions can be made valid generally.