• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 춘계학술대회
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• pp.513-514
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• 2016

최근 뇌파에 대한 연구가 아주 활발하게 진행되고 있다. 이러한 뇌파를 분석하기 위해서는 뇌파센서를 이용하여 뇌파를 수집하고 뇌파의 주파수 분석 등을 이용하여 뇌파를 분석할 수 있다. 이러한 분석을 위하여 본 논문에서는 NeuroSky 사의 mindwave mobile 뇌파 센서를 이용하여 뇌파를 수집하고 수집된 뇌파의 주파수 분석을 이용하여 delta, theta, alpha, SMR, beta 파를 분석하고 이러한 주파수별 뇌파가 집중도와 어떤 상관관계를 갖고 있는지 분석하고자 한다. 이러한 분석을 통하여 일반적으로 알려진 집중도와 beta파의 밀접한 관계뿐만 아니라 다른 주파수 성분과의 상관관계도 분석할 수 있을 것이다. 이러한 기초연구를 통하여 보다 발전된 형태의 뇌파를 연구할 수 있을 것이다.

• 한국산림과학회지
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• 제98권1호
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• pp.88-93
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• 2009

자연을 비롯한 산림 경관은 인간의 심리적 안정에 큰 역할을 한다고 알려져 왔다. 본 연구는 산림 경관의 심리적 안정 효과를 실증적으로 밝혀내고자 수행되었다. 자료의 수집을 위하여 도시, 산림, 산림과 물에 해당되는 각 9개의 경관이 선정되었다. 이들 3 종류의 총 27개 경관사진이 30명의 피험자에게 심리적 생리적 영향이 미치는지를 조사하였다. 심리적 안정을 나타내는 뇌파(${\alpha}$파)와 PRS(Perceived Restorativeness Scale), PANAS(Positive and Negative Affect Schedule)점수가 각각 생리적, 그리고 심리적 연구변수로 측정되었다. 자료의 분석결과 산림과 물, 산림, 그리고 도시 경관 순으로 생리적 심리적 안정에 영향을 주는 것으로 나타났다.

• 한국안전학회지
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• 제28권3호
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• pp.107-113
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• 2013

Problem solving and/or decision making process usually encountered in human living consists of a sequence of human behaviors based upon his/her knowledge. Thus, Rasmussen introduced Skill-Rule-Knowledge paradigm to countermeasure human errors that can occur in Nuclear Power Plants. Unfortunately however, it was not so easy as expected since objective evidence have not been obtainable with conventional research techniques. With the help of EEG band pawer ratio techniques, this study tried to get psycho-physiological symptoms of human errors, if any, while human beings perform knowledge-based behaviors such as simple arithmetic computations with different difficulty level. A set of simulated works was carried out with a computer station. Four kinds of arithmetic computation tasks were given to 10 health male under-graduate students on different day individually, and during the experiment, EEG and ECG was measured continuously for objective psycho-physiological analysis. According to the results, ${\alpha}$/(${\alpha}+{\beta}$) as well as ${\alpha}/{\beta}$ band power ratio were sensitive to task difficulty level which consistently decreased both. However, any one of them failed to reveal the influence of tasks with different difficulty level in the aspect of task duration time. On the contrary, Heart Rate Variability was more suggestive than expected. To make a conclusion, it can be said that band power of EEG waves will be helpful in not only assessment of work difficulty level but also assessment of workers' skill development if supported by cardiac function such as HRV.

• 천문학회보
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• 제40권1호
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• pp.83.4-84
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• 2015

We report that a strong downflow event caused three-minute oscillations in the solar atmosphere. Our observations were carried out by using the Fast Imaging Solar Spectrograph (FISS) of the 1.6 meter New Solar Telescope (NST) and the Interface Region Imaging Spectrograph (IRIS). Our main findings are as follows: (1) The strong downflow was seen at the $H{\alpha}$ absorption line at first, and then appeared at the Si IV and C II emission lines. It seems that the characteristics of the downflow are consistent with a coronal rain event. (2) After the event, oscillations of velocity were identified in the chromospheric lines and transition region lines. (3) The amplitudes of oscillations were 2km/s at Mg II line and 3km/s at C II and Si IV lines and decreased with time. (4) The period of the oscillation was 2.67 minutes at first, but gradually increased with time. Our findings are in agreement with Chae & Goode (2015)'s theory that of acoustic waves generated by a disturbance in a gravitationally-stratified medium.

• 한국조경학회지
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• 제26권1호
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• pp.36-43
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• 1998

We compared the electroencephalogram, blood pressure, and sensory evaluation inspectioni several color of Petunia hybrida to analyze the physiopsychological effects of a plant. Considering occipital is related to visuosensory field, green color is thought as mild visual stimulator unlike to pink color. The results are coincident with the well-known facts that green color is less stimulating color. It is also accorded with the sensory evaluation results that green color showed te feeling of blue and stable. In case of green color is showed the feeling of blue and stable. In case of green color the generatioin of alpha waves increased according to the increase color area. Therefore it is thought that green color helps decrease of visual stimulation and increase in visual stability. However it is thought that pink has less physiopsychological effects on human beings depending on area sizes than green has.

• Structural Engineering and Mechanics
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• 제16권1호
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• pp.35-46
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• 2003

The histories and distributions of dynamic stresses in an orthotropic hollow cylinder under sinusoidal impact load are obtained by making use of eigenfunction expansion method in this paper. Dynamic equations for axially symmetric orthotropic problem are founded and results are carried out for a practical example in which an orthotropic hollow cylinder is in initially at rest and subjected to a dynamic interior pressure $p(t)=-{\sigma}_0(sin{\alpha}t+1)$. The features of the solution appear the propagation of the cylindrical waves. The other hand, a dynamic finite element solution for the same problem is also got by making use of structural software (ABAQUS) program. Comparing theoretical solution with finite element solution, it can be found that two kinds of results obtained by two different solving methods are suitably approached. Thus, it is further concluded that the method and computing process of the theoretical solution are effective and accurate.

• Journal of Astronomy and Space Sciences
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• 제33권3호
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• pp.167-172
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• 2016

We used the 4 m Discovery Channel Telescope (DCT) at Lowell observatory in 2014 to observe the Guitar Nebula, an Hα bow-shock nebula around the high-velocity radio pulsar B2224+65. Since the nebula's discovery in 1992, the structure of the bow-shock has undergone significant dynamical changes. We have observed the limb structure, targeting the "body" and "neck" of the guitar. Comparing the DCT observations to 1995 observations with the Palomar 200-inch Hale telescope, we found changes in both spatial structure and surface brightness in the tip, head, and body of the nebula.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.521-521
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• 2013

Collective Thomson scattering (CTS) system is being developed in KAERI based on high power gyrotrons. CTS is a promising diagnostic method to measure fast ion distributions and potentially the fusion product alpha particles in magnetically confined plasmas. By utilizing millimeter-waves from high power gyrotrons as a probing beam, spatially and temporally resolved 1-D ion velocity distributions can be obtained from the scattered radiation with less scattering geometrical constraints. The pulse modulation of gyrotrons enables to separate scattering signal from ECE background noises. The feasibility was assessed with the calculation of spectral density functions under the condition of KSTAR plasmas. Further CTS system requirements are also discussed.

• 교육시설 논문지
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• 제21권6호
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• pp.33-42
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• 2014

The objective of this study is to investigate learning factors (stability, attention and activation) in school by electroencephalogram (theta, alpha and beta waves) analysis during relaxed or concentrated. In order to measure electroencephalograms, MP 150 by Biopac and ECI Electro-Cap are employed. Three types of color temperatures (3000K, 5000K, 7000K) are used and 13 undergraduate and 12 graduate students are selected as experimental subjects. When subjects are relaxed during contemplation or concentrated during mental arithmetic, we compare with stability, attention and activation indices. The test results show that subjects were stable when color temperature is 5000K. Subjects gave best attention when color temperature is 7000K. Subjects activated well when color temperature is 3000K during relaxed attention. However, subjects activated rigorous when color temperature is 7000K during constrained attention.

• 한국해안해양공학회지
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• 제18권4호
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• pp.321-328
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• 2006

본 연구에서는 범용난류유동수치모형인 FLUENT를 이용하여 다양한 유공벽의 두깨와 흐름 조건에 대한 수치실험을 실시하고, 그 결과를 이용하여 유공벽의 두께가 고려된 새로운 에너지 손실계수 산정식을 얻었다. 그 결과 유공벽의 두께가 두꺼워질수록 에너지손실계수 ${\alpha}$가 감소하여 기존의 예연오리피스 감식에 의한 값의 최대 40%정도까지 감소함을 할 수 있었다. 새로운 공식의 타당성을 검토하기 위해 본 연구에서 계시한 공식을 이용하여 파 반사율을 구하고 기존의 공식에 의한 반사율 및 수리실험을 통해 측정된 결과와 비교하였으며, 새로운 공식의 우수성이 확인되었다.