• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2009년도 정보 및 제어 심포지움 논문집
• /
• pp.145-147
• /
• 2009

This research measures EEG signals which are generating on head skin and extracts brain concentration level related with brain activity. We have developed concentration wireless transmission system by displaying this EEG signal on PDA mobile device. The front head was used for measuring EEG signal and INA128 with TL084 and analog elements was used for measuring EEG signal, amplifying and filtering the signal. Measured analog EEG signals changed into digital signals by using ADC of PIC24FJ192 with 10bit resolution and 500Ks/s sampling rate. So The changed digital signals have transmitted to the PDA by using bluetooth. LabView 8.5 was also used for FFT transformation, frequency and spectrum analysis of the transferred EEG signal. As a result, $\alpha$ wave, $\beta$ wave, $\theta$ wave and $\delta$ wave were classified. we extracted the concentration index by adapting concentration extraction algorithm. This concentration index was transferred into PDA by wireless module and displaying.

• KIEAE Journal
• /
• 제11권3호
• /
• pp.49-56
• /
• 2011

The effect of soundscape has been analyzed by questionnaire results. Nowadays, EEG is used to identify the human reponses due to exterior stimuli such as soundscape sound sources. So, it is very meaningful to know the EEG response to soundscape sound sources. In the present study, the sound sources of soundscape were heard to subjects in order to find out the relationship between questionnaire results and electroencephalogram results through lab test. And stimulated part of brain for evaluating words were sought in this experiment too. The results of the study are as follows : the sound source of bird+music causes more ${\alpha}$-wave rise than other sound sources and the ${\alpha}$-wave stimulated region of brain is occipitallobe. In case of ${\beta}$-wave, the left part of brain is excited. ${\delta}$-wave is on frontallobe and ${\Theta}$-wave is on right part of brain. The evaluating words for soundscape can be categorized into four groups. These results could be used for basic materials of soundscape effects analysis.

• Journal of Astronomy and Space Sciences
• /
• 제29권1호
• /
• pp.47-49
• /
• 2012

Massive binary stars lose mass by two mechanisms: jet-driven mass loss during periods of active mass transfer and by wind-driven mass loss. Beta Lyrae is an eclipsing, semi-detached binary whose state of active mass transfer provides a unique opportunity to study how the evolution of binary systems is affected by jet-driven mass loss. Roche lobe overflow from the primary star feeds the thick accretion disk which almost completely obscures the mass-gaining star. A hot spot predicted to be on the edge of the accretion disk may be the source of beta Lyrae's bipolar outflows. I present results from spectropolarimetric data taken with the University of Wisconsin's Half-Wave Spectropolarimeter and the Flower and Cook Observatory's photoelastic modulating polarimeter instrument which have implications for our current understanding of the system's disk geometry. Using broadband polarimetric analysis, I derive new information about the structure of the disk and the presence and location of a hot spot. These results place constraints on the geometrical distribution of material in beta Lyrae and can help quantify the amount of mass lost from massive interacting binary systems during phases of mass transfer and jet-driven mass loss.

• 한국지구과학회지
• /
• 제41권4호
• /
• pp.344-355
• /
• 2020

Tropical cyclone scale vortices and associated Rossby waves were investigated numerically using high-resolution barotropic models on the global domain. The equations of the barotropic model were discretized using the spectral transform method with the spherical harmonics function as orthogonal basis. The initial condition of the vortex was specified as an axisymmetric flow in the gradient wind balance, and four types of basic zonal states were employed. Vortex tracks showed similar patterns as those on the beta-plane but exhibited more eastward displacement as they moved northward. The zonal-mean flow appeared to control not only the west-east translation but also the meridional translation of the vortex. Such a meridional influence was revealed to be associated with the beta gyre and the Rossby wave, which are formed around the vortex due to the beta effect. In the case of the basic zonal state of climatological mean, the meridional translation speed reached the maximum value when the vortex underwent recurving.

• 한국안전학회지
• /
• 제26권3호
• /
• pp.83-90
• /
• 2011

It is well known that urgency resulted from time stress can be a great cause to industrial accidents. Therefore, time stress has been studied in the aspect of macroscopic view, namely industrial safety management, but has not been studied in microscopic view such as psychophysiological approach. Among diverse psychophysiological indices, Electroencephalogram(EEG) would be on of the most objective psychophysiological research technique on human errors though few research has been taken yet. This study aimed to get characteristics of human error while committing a simple arithmetic addition task by utilizing the power spectrum technique of EEG data. Each experiment was composed of 2 tasks under different condition - with and without time stress. As subjects, 5 young undergraduate students in their early twenties participated in this study. The results advocated a well-known fact that time stress downgrades the performance of human workers. However, correct answer rate and response time were not significantly influenced by time stress factor which might be explained by the constructural factor adopted in the present study. As in the previous studies, among various EEG-related measures, relative band power ratios of ${\alpha}$ and ${\beta}$ waves to sum of ${\alpha}$,${\beta}$,${\theta}$ wave powers, namely $P_{{\alpha}/({\alpha}+{\beta}+{\theta})}$ and $P_{{\beta}/({\alpha}+{\beta}+{\theta})}$ seemed to be the most effective measures to grasp variation of brain activities in time-stressed situation so that discussions were expanded about their variations.

• 동의신경정신과학회지
• /
• 제19권3호
• /
• pp.289-297
• /
• 2008

Attention Deficif and Hyperactivity Disorder(ADHD) is a behavioral disoerder characterized by inattentiveness, impulsivity and hyperactivity, This is the case of a ADHD child treated with Neurofeedback therapy. ADHD Diagnotic System(ADS), Conner;s parent rating scale, ADHD-Rating Scale (ARS), Korean Child Behavior Checklist(K-CBCL) were compared between before and after Neurofeedback theraphy. And the EEG(Theta wave, SMR wave and Beta wave) data of each ession was analysed. As a result, Neurofeedback therapy is efficient in the treatment of ADHD.

• 수산해양교육연구
• /
• 제19권3호
• /
• pp.502-509
• /
• 2007

This study evaluates thermal comfort by air conditioner temperature raising at the point of time that human body begins to adapt. Thermal comfort according to change of time enters by uncomfortable area gradually at general cold room temperature that magnetic pole is in human body. However, can know that keep continuous thermal comfort in case raise temperature in human body adaptation visual point. Experiments were performed in environmental chamber. Subjects were selected 4 men and 4 women whose life cycle were proved that are similar. The subjects stay in the pretesting room during the 30 minutes and enter the testing room under each experiment conditions. During the experiment, brain wave, electrocardiogram, blood pressure and thermal comfort and sensation responses were measured. In this study, physiological and psychological responses correspond under temperature raising at human body adaptation.

• Computational Structural Engineering : An International Journal
• /
• 제2권1호
• /
• pp.43-50
• /
• 2002

This paper presents a method to predict dynamic responses of floating bodies in the time domain. Because of the frequency-dependence of the radiation wave forces, the memory effect must be taken into account when the responses are evaluated in the time domain. Although the formulations firstly developed by Cummins (1962) have been well-known for this purpose, the effective numerical procedure has not been established yet. This study employs FFT (Fast Fourier Transform) algorithm to evaluate the memory effect function, and the equations of motion of an integro-differential type are solved by Newmark-β method. Numerical examples for a truncated circular cylinder have indicated the effectiveness of the proposed numerical procedure.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1996년도 춘계학술발표회논문집(4)
• /
• pp.443-448
• /
• 1996

In this paper, the 100 % non-inductive current drive scenarios are addressed for the steady-state operation on KT-2 tokamak, with the profile control using fast wave and lower hybrid wave as the external tools. Considering the stability, the well-aligned current profiles with a reversed-shear and $q_{min}$ > 2.0 has been favor-able in high ${\beta}_{p}$ plasma, together with a possibly higher bootstrap current fraction. Therefore, the effects of the auxiliary heating power profile on the control of MHD favorable current profile are evaluated in detail.

• 한국산학기술학회논문지
• /
• 제12권6호
• /
• pp.2588-2597
• /
• 2011

우울증이나 불안과 같은 정서적 특성이나 BIS/BAS 같은 행동성향 특성과 관련하여 전전두엽에서 뇌파 비대칭 연구는 주로 알파(${\alpha}$)파를 중심으로 이루어져 왔다. 하지만 알파(${\alpha}$)파 만으로 이러한 특성을 구분하는 것에 대한 한계점이 제기 되면서 베타(${\beta}$)파와 같은 다른 밴드를 중심으로 한 연구의 필요성이 제기되고 있다. 이에 따라 본 연구는 만4세 유아 44명을 대상으로 전전두엽에서 뇌파를 측정하여 알파(${\alpha}$)파 비대칭성과 베타(${\beta}$)파 비대칭성을 독립적으로 분리하여 BIS/BAS적 경향성과 비교 분석하였고, 이들 세 가지 특성을 조합하여 유아의 정서와 행동 성향을 8가지로 구분하는 방법을 제시하였다. 연구결과 N의 계수해석으로 BIS적 특성은 베타(${\beta}$)파 비대칭으로, BAS적 특성은 알파(${\alpha}$)파 비대칭 특성으로 판별하는 것이 확률적으로 높은 정확성을 보인다는 것을 발견하였다. 정서적 특성은 기존의 연구 결과와 같이 알파(${\alpha}$)파 비대칭으로 판단하였다. 이것은 뇌 발달 과정에서 만 4세 유아의 시냅스 형성이 좌뇌가 우뇌보다 활발하다는 연구 결과와 일치하는 것으로 판단된다.