• 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 Biomedical Engineering Research
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• v.15 no.4
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• pp.383-388
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• 1994

Chaotic analysis of EEG signal responding to auditory stimulus with various carrier frequency and constant triggering frequency is given in this paper. The EEG signal is obtained from the digital 12channel EEG system made in our laboratory. The carrier frequency is varied from 1 kHz to 3 kHz by 0.5 kHz step. Chaos analysis such as pseudo phase space portrait, Lyapunov exponent, and so on is done on the auditory stimulated evoked potential. This result is found to be quite consistent with the well known results from the psychological perception theory.

• Science of Emotion and Sensibility
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• v.1 no.1
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• pp.69-78
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• 1998

Sleep deprivation may affect the brain functions such as cognition and consequently, dynamics of the BEG. We examined the effects of sleep deprivation on chaoticity of the EEG. Five volunteers were sleep-deprived over a period of 24 hours They were checked by EEG during two days. thc first day of baseline period and the second day of total sleep deprivation period. EEGs were recorded from 16 channels for nonlinear analysis. We employed a method of minimum embedding dimension to calculate the first positive Lyapunov exponent. Fer limited noisy data, this algorithm was strikingly faster and more accurate than previous ones. Our results show that the sleep deprived volunteers had lower values of the first positive Lyapunov exponent at ten channels (Fp1, F4. F8. T4, T5. C3, C4. P3. P4. O1) compared with the values of baseline periods. These results suggested that sleep deprivation leads to decrease of chaotic activity in brain and impairment of the information processing in the brain. We suggested that nonlinear analysis of the EEG before and after sleep deprivation may offer fruitful perspectives for understanding the role if sleep and the effects of sleep deprivation on the brain function.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2002.11a
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• pp.461-467
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• 2002

Signals produced from the brain had been considered as a noise that is caused by the stochastic process until 1980. The recent non-linear dynamic theory researches, however, reported that these signals are meaningful and deterministic chaos signals in which they show how the brain deals with various information Since this report a wide range of researches has been carried out and still in progress. Thus, by using the correlational dimension, one of the non-linear analytical methods, the characteristics of the brain signals can be analyzed. In this thesis, the scent of lavender, which stimulates the olfactory sense, is introduced to measure EEG with the International 10-20 electrode system on 16 channels, and to analyze the interrelationship between the original signals before the stimulation and the changed signals after the stimulation. Finally, the effect of the scent stimulation to the brain is analyzed. The purpose of this thesis is to apply these analyzed results to the computerized mapping of the brain signals and possible ways of specifying the source of the brain signals through various medical applications.

• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.137-140
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• 2008

During CHAOS (2003, 2006) and SSGH projects (2007), acoustic investigation including hydroacoustic (HA), side-scan sonar (SSS) and highresolution sparker seismic (HSS) surveys was carried out on the northeastern Sakhalin slope ($53^{\circ}56'\;N$, $143^{\circ}52'\;E$ to $54^{\circ}40'\;N$, $144^{\circ}32'\;E$). More than 130 methane seeps with high backscatter intensity are identified on SSS mosaic, which are well accompanied with gas flares in the water column on HA profiles and subbottom gas chimneys on HSS profiles. It is likely that that some seeps align along a NW strike parallel to the Lavrentiev Fault.

• The Journal of the Korea Contents Association
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• v.5 no.6
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• pp.343-350
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• 2005

During the design of a successful digital watermarking systems, Pseudo-Noise(PN) sequences are widely used to modulate information bits into watermark signals. In this method, the number of bits that can be hidden within a small image by means of frequency domain watermarking is limited. In this paper, we show the possibility of introducing chaotic sequences into digital watermarking systems as potential substitutes to commonly used PN-sequences. And we propose a method that transforms the text to chaotic sequence. In our current implementation, we show how the sample text is expressed by an implied unit data(watermark) and the implied unit data is regenerated into the original left. Because we use this implied data as watermark for information hiding, we can insert much more watermark compared with previous method.

• Journal of Information Science Theory and Practice
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• v.4 no.1
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• pp.49-64
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• 2016

What government does/fails to do is conveyed to the public largely by records and information of various types in the public service, without which there will be no government. When records are poorly managed, much time is involved in sorting and locating needed information from large volumes of records. The rate of records misplaced or lost from which useful information for decision making is usually obtained makes it difficult to provide concise and up-to-date records of both past and present operations, raising the challenge of effective record-keeping. Thus this study examined records management practices in selected local government councils in Ogun State, Nigeria, adopting the descriptive survey research method using questionnaires for data collection. Its population comprised 415 records of personnel in the selected councils, of which 208 were sampled using simple random technique. From the 208 copies of the questionnaire administered on the registry personnel, 150 copies were useable, with a 72.12% response rate. Descriptive statistics were used for the analysis. The results indicated a prevalence of paper as the dominant medium for recording/conveying information in the councils with most of these being either in active state, semi-active, and vital and were kept and maintained in the registry, while in-active records were kept in the records store. Storage facilities for record-keeping were insufficient. Security measures against unauthorized access to records were by restrictions and subject users to managerial clearance. The study concluded that council records were in chaos and recommended the formulation of coherent records management policy, adequate budgetary provision, and adequate finance.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.42 no.1
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• pp.13-21
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• 2005

This paper presents a fuzzy model-based approach for synchronization of time-delay chaotic system with input saturation. Time-delay chaotic drive and response system is respectively represented by Takagi-Sugeno (T-S) fuzzy model. Specially, the response system contains input saturation. Using the unidirectional linear error feedback and the parallel distributed compensation (PDC) scheme, we design fuzzy chaotic synchronization system and analyze local stability for synchronization error dynamics. Since time-delay in the transmission channel always exists, we also take it into consideration. The sufficient condition for the local stability of the fuzzy synchronization system with input saturation and time-delay is derived by applying Lyapunov-Krasovskii theory and solving linear matrix inequalities (LMI's) problem. A numerical example is given to demonstrate the validity of the proposed approach.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.37 no.3
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• pp.55-62
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• 2000

This paper presents an analysis of the chaotic behavior in the discrete-time voltage mode chaotic generator fabricated using 0.8${\mu}{\textrm}{m}$ single poly CMOS technology. An approximated empirical equation is extracted from the measurement data of a nonlinear function block. Then the bifurcation diagram is simulated according to input variables and Lyapunov exponent λ which represent a dependence on an initial value is calculated. We show the interrelations among time waveforms, state transition, and power spectra for the state condition of chaotic circuit, such as equilibrium, periodic, and chaotic state. And results of experiments in the chaotic circuit with the $\pm$2.5V power supply and sampling clock frequency of 10KHz are shown and compared with the simulated results.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.8 no.6
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• pp.528-533
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• 2015

In the construction of USN environment, the implementation of a safe sensor network using wireless communications can be said to be the most important factor in the entire system. Although USN communication uses wireless communications to enhance accessability and non-contact capability, this results in the security vulnerability, thus endangering the system. In this regard, we propose a security protocol that can be effectively applied to USN, a multi-sensor network. The proposed protocol is a method using an individual chaotic system, and it is a security protocol to synchronize the main chaotic system mounted on each sensor and prepared key values into the initial values, and to communicate with the use of the synchronized values as symmetric keys. The communication protocol proposed in this paper is expected to yield good results as a new method to resolve security problems of USN and program capacity limitations of sensor nodes if subsequent studies continue to be carried out.