• The Journal of the Acoustical Society of Korea
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• v.28 no.4
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• pp.356-362
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• 2009

In modern society, most people of the world are densely populated in cities so that the traffic sound has a very significant meaning. people tend to classify traffic sound as a noise pollution while they are likely to categorize most nature sound as positive. In this paper, we applied various forms of FFT filters into white noise belonged in nature sound to find frequency characteristics of white noise which preferred by people and confirm its correlation with nature sound. In addition, we conducted an analysis through the comparison of various traffic and nature sound waveforms and spectra. As a result of analysis, the traffic sound have characteristics which sound energy had concentrated on specific frequency bandwidth and point of time compared to nature sound. And we confirmed the fact that these characteristics had negative elements to which could affect to people. Lastly, by letting the subjects listen directly to both traffic and nature sound through brainwave experiment using electrode, the study measured the energy distribution of alpha waves and beta waves. As a result of experiments, it has been noted that urban sound created a noticeably larger amount of beta waves than nature sound; on the contrary, nature sound generated positive alpha waves. These results could directly confirm the negative effects of traffic sound and the positive effects of nature sound.

• Economic and Environmental Geology
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• v.32 no.4
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• pp.379-384
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• 1999

In order to know the characteristics of attenuation of coda wave in the Kyungsang Sedimetary Basin, quality faclity factor for coda wave (coda Q) is estimated from the earthquake data recorded in the KIGAM local seismic network. Thesingle scattering model for coda wave generation is adopted is adopted in estimating coda Q. In the present study, coda Q(Qc)is estimated in the range of $\alpha$=1.5~3.0, where $\alpha$ denotes the normalized time to S-wave travel time and expressed in terms of frequency (f). The deduced function in the range of 1 to 25 Hz is Qc=36.8283$f^{1.15095}$ which represents the strong dependence of coda Q on frequency. It is found that the difference of Qc between U-D, N-S, and E-W components is negligible. This fact suports the back scattering therory that coda wave originates from scattered waves by randomly distributed heterogenities in the crust On the other hand, it is observed that the coda Q increases with increasing epicentral distence. This observation suggests that QC increases with depth.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2000.04a
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• pp.99-103
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• 2000

There are two approaches in the study of emotion in the physiological psychology. The first is to clarify the brain mechanism of emotion, and the second is to evaluate objectively emotions using physiological responses along with our feeling experience. The method presented here belongs to the second one. Our method is based on the "level-crossing point detection" method. which involves the analysis of frequency fluctuations of EEG and is characterized by estimation of emotionality using coefficients of slopes in the log-power spectra of frequency fluctuation in alpha waves on both the left and right frontal lobe. In this paper we introduce a new theory of estimation on an individual's emotional state by using our non-invasive and easy measurement apparatus.

• Journal of the Korean Academy of Child and Adolescent Psychiatry
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• v.1 no.1
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• pp.40-54
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• 1990

The author studied EEG differences among normal, children, children with emotional behavioral problems determined by Rutter's questionnaire and children with attention-deficit hyperactivity disorder according to DSM-III-R. The results are as follows ; There were no differences in incidence and pattern of abnormal EEG between normal control children and children with emotional behavioral problems. But children with attention-deficit hyperactivity disorder tend to show lower average amplitude, and less wave percentage time of alpha wave in occipital area than normal did, furdermore wave percentage time of alpha wave appeared more in left occipital area than in right occipital area, These results demonstrated that emotional behavioral problems in elementary school children may not be related to EEG abnormality, Where as children with attention deficit hyperactivity disorder showed underdeveloped alpha waves as compared with normal control children.

• Journal of the Korean Society for Nondestructive Testing
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• v.18 no.1
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• pp.1-9
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• 1998

The attenuation of acoustic emission (AE) waves was evaluated for injection-molded short-fiber-reinforced thermoplastic composites employing simulated AE waves. Values of attenuation coefficient (${\alpha}$) decreased more with increasing fiber volume fraction ($V_f$) than that expected from a simple linear relation between ${\alpha}$ and $V_f$. The effect of wave attenuation was taken into account in a quantitative analysis of the AE peak amplitude distribution which was obtained from each zone partitioned in a specimen gage portion. The amplitude distribution compensated for the measured attenuation loss was exhibited almost similar in every zone of the specimen. Consequently, it was, shown that the AE amplitudes obtained from fiber/plastic composites were considerably affected by the attenuation.

• Korean Journal of Food Science and Technology
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• v.12 no.1
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• pp.41-44
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• 1980

The model compounds of Vitamin $B_1$ 3-benzyl-4-methylthiazolium bromide, (1), 3, 4-dimethylthiazolium iodide (2) and 2-($\alpha$-hydroxyethyl)-3-benzyl-4-methylthiazolium bromide (3) were prepared by the organic synthesis. Colorimetric determination with phosphotungstic acid showed an increase of $1.1{\sim}1.2$ folds with compound (1) and $1.5{\sim}1.9$ folds with compound (3) when readings were carried out after an overnight, compared with immediate readings. Colorimetry with 2.6-dibromoquinone chloroimide yielded the compound (1) being $2.2{\sim}2.5$ folds higher than the compound (3). The half wave potentials and diffusion currents of anodic and cathodic waves of polarography with the same concentration of the compounds (1), (2) and (3) also resulted in different values of their waves. Therefore, it was a firm conclusion that any values obtained from quantitative analysis with this model compounds (1), (2) and (3) were not directly applicable to those of $B_1$.

• Journal of Families and Better Life
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• v.26 no.4
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• pp.13-25
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• 2008

This study of a music therapy program for the 18 subjects residing in Jeollanam-do province was conducted two times per week during 4 months totalling 17 times in order to evaluate the reduction of the characteristics of patients suffering from stress disorder patients such as depression, and anxiety, Though the experiment for non-symmetric level the concentration and appearance of Alpha wave were determine to be stable but the findings from non-symmetric level according to the left-right brain activity were not significant for T-test, though its effective intermission of music therapy due to variation of the mean values was demonstrated, and the variation of the Alpha wave appearance rate was also significant for the statistics of the T-test for the effectiveness of the music therapy. And for the reduction of depression, emotion, and state-trait anxiety between groups divided into the control group and the experiment, pre-measurement and post-measurement comparisons through psychological tess, validated the effectiveness of music therapy for Posttraumatic stress disorder patients. First of all, this study was conducted in the situation of scarce study cases and program developments for the efficacy of music therapy for the patients suffering from Posttraumatic stress disorders without precedent studies of scientific identification through brain wave measurement. Because this study is insightful in the context of validating the efficacy of musical treatment, we expect that these kinds of studises will be continued.

• The Korean Journal of Physiology
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• v.25 no.2
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• pp.147-158
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• 1991

The effects of noradrenaline on the spontaneous contraction recorded from a strip of mucosa-free antral circular muscle were studied in the guinea-pig stomach, and the changes in slow waves and membrane resistance were analyzed in order to elucidate the mechanism for the excitatory response to noradrenaline. Electrical responses of circular muscle cells were recorded using glass microelectrodes filled with 3 M KCI. Electrotonic potentials were produced to estimate membrane resistance by the partition stimulating method. All experiments were performed in tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. The results obtained were as follows: 1) The spontaneous contractions were potentiated dose-dependently by the application of noradrenaline. 2) Through the experiments using adrenoceptor-blockers, the strong excitatory effect via $[\alpha}-adrenoceptors$ and the weak inhibitory efffect via ${\beta}-adrenoceptors$ were noted. 3) Noradrenaline produced hyperpolarization of membrane potential, and increases in the amplitude and the maximum rate of rise of slow waves. 4) In the presence of apamin, Ca-dependent K channel blocker, the characteristic hyperpolarization was not developed. However, the excitatory effect of noradrenaline on spontaneous contraction remained. 5) Membrane resistance was reduced during the hyperpolarized state by the application of noradrenaline, and the change of membrane resistance and the hyperpolarized state were completely abolished by apamin. From the above results, following conclusions could be made: Excitatory responses to noradrenaline result from the dominant ${\alpha}-excitatory$, and the weak ${\beta}-inhibitory$ action of noradrenaline. Hyperpolarization of membrane potential by noradrenaline is due to the activation of Ca-dependent K channel.

• Journal of Sensor Science and Technology
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• v.12 no.6
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• pp.289-297
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• 2003

In this paper, we propose accurate classification method of an EEG signals during a mental tasks. In the experimental task, subjects achieved through the process of responding to visual stimulus, understanding the given problem, controlling hand motions, and select a key. To recognize the subjects' selection time, we analyzed with 4 types feature from the filtered brain waves at frequency bands of $\alpha$, $\beta$, $\theta$, $\gamma$ waves. From the analysed features, we construct specific rules for each subject meta rules including common factors in all subjects. In this system, the architecture of the neural network is a three layered feedforward networks with one hidden layer which implements the error back propagation learning algorithm. Applying the algorithms to 4 subjects show 87% classification success rates. In this paper, the proposed detection method can be a basic technology for brain-computer-interface by combining with discrimination methods.

• Journal of Biomedical Engineering Research
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• v.39 no.1
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• pp.55-61
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• 2018

The purpose of this study was to investigate the effect of a pillow simulated with cranial sacral therapy (CST) on sleep induction using electroencephalography (EEG). This study included 12 voluntary participants divided into experimental group (CST group) and control group (Non-CST group) to observe EEG changes. The position of the electrode for EEG measurement consists of 8 channels electrodes (Fp1, Fp2, F3, F4, T3, T4, P3 and P4). In this study, we measured the fall asleep time, change of brain activity and sleep wave ratio using EEG wave (${\delta}$, ${\theta}$, ${\alpha}$, ${\beta}$ and ${\gamma}$). As a result, the mean fall asleep time of the experimental group was shorter than that of the control group significantly (p < 0.001). Also in comparison with the control group, both the delta (d) and theta (q) wave corresponding to the slow waves showed a larger increase and the alpha (a) wave showed a larger decrease significantly. The slow waves of experimental group showed a higher rate of significant increase than the control group (p < 0.001). Therefore this study showed that pillow based on CST had an effective in improving sleep induction and quality.