• 대한교통학회지
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• 제34권6호
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• pp.560-569
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• 2016

운전자의 정신부하는 교통사고를 감소하는데 중요한 역할을 하는 것으로 선행연구에서 나타나고 있다. 본 연구에서는 도로 및 환경요소 뿐만 아니라 운전자의 알파파, 베타파, 감마파를 측정할 수 있는 운전시뮬레이터를 활용하여 분석자료를 확보하였다. 운전자의 운전부하와 감마파의 연관성을 분석하기 위한 방법으로 로지스틱모형을 적용하였다. 분석결과, 도로의 커브가 많을수록 운전자의 베타 영역은 증가하는 반면 알파와 감마 영역은 감소되는 것으로 나타났다. 그리고, 운전부하는 감마영역과 음의 상관관계를 지닌 것으로 나타났다. 결론적으로, 직선구간에서의 도로주행이 운전자의 스트레스를 줄이고 행복감을 높일 수 있을 것으로 판단된다.

• 생물정신의학
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• 제23권3호
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• pp.102-107
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• 2016

This review will summarize EEG studies of learning and memory based on frequency bands including theta waves (4-7 Hz), gamma waves (> 30 Hz) and alpha waves (7-12 Hz). Authors searched and reviewed EEG papers especially focusing on learning and memory from PubMed. Theta waves are associated with acquisition of new information from stimuli. Gamma waves are connected with comparing and binding old information in preexisting memory and new information from stimuli. Alpha waves are linked with attention. Eventually it mediates the learning and memory process. Although EEG studies of learning and memory still have controversial issues, the future EEG studies will facilitate clinical benefits by virtue of more developed and encouraging prospects.

• 지구물리
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• 제5권1호
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• pp.1-8
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• 2002

한반도 남동지역에서의 Lg 감쇠 연구는 산업 지역에 놓인 활성단층으로 여겨지는 양산단층의 존재로 매우 중요하다. 두 관측점법에 의한 Lg 감쇠를 해석한 결과, 0.87 - 10 Hz 구간이 $${＼gamma}=(0.009±0.0005)＼;f^{0.06+0.03}$$이다. ${＼gamma}$값에서 변환된 ${Q_{Lg}}^{-1}$값은 동일한 지역에서 측정된 S파의 값보다 매우 높고, 10Hz 가까운 영역에서는 세계에서도 가장 높은 수준이 검출되었다. 이 높은 값은 동해에 의한 Lg 차단 효과이거나, 조사지역의 지각두께 변화와 연관이 된 것으로 보인다.

• 천문학회보
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• 제35권1호
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• pp.83.2-83.2
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• 2010

During the formation of cosmic web, collisionless shock waves are produced around and inside the substructures. In these shock waves electrons and ions are accelerated to such high energies that they can produce gamma rays in several ways. Many authors have studied the contribution of shock-induced radiation to the cosmic gamma-ray background. However not all the important physical processes are included in their calculation. By considering more complete physical process, we re-investigate the problem. In our model, the energy distribution of the cosmic rays (CRs) are calculated by widely accepted diffusive shock acceleration model, both primary and secondary CR electrons are included, both inverse Compton scattering and bremsstrahlung process are considered. The difference of the results are discussed.

• 천문학회지
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• 제29권spc1호
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• pp.99-102
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• 1996

I discuss implications of gamma-ray emission from blazars based on electron acceleration by shock waves in a relativistic jet. The number spectrum of electrons turns out to be a broken power law; while at low energies the power law index has a universal value of 2, at high energies it steepens to an index of 3 because of strong radiative cooling. This spectrum can basically reproduce the observed spectral break between X-rays and gamma-rays. I show that energetics of relativistic jets can be well explained by this model. I estimate physical quantities of the relativistic jets by comparing the prediction with observations. The results show that the jets are particle dominated and are comprised of electron-positron pairs. A connection between gamma-ray emission and radiation drag is also discussed.

• 한국콘텐츠학회논문지
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• 제17권3호
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• pp.571-577
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• 2017

2015 개정 교육과정을 통해 소프트웨어 교육의 일환으로 프로그래밍 교육이 초등학교 정규교과에 도입된다. 프로그래밍 교육이 문제해결력에 미치는 영향에 대한 분석을 통해 효과적인 교수 학습 방법이 제시될 수 있다. 본 논문에서는 학생들의 학업 성취도에 따라 두 그룹으로 나누고 엔트리와 엔트리용 센서보드를 활용한 5차시 분량의 학습 프로그램을 개발하고 그것을 적용한 수업을 실시하였다. 수업 전 후에 문제해결 검사 도구를 활용하여 학생들의 감마파와 뇌파집중 지표의 변화를 측정하고 분석하였다. 그 결과 학업 성취도가 우수한 그룹의 학생들은 프로그래밍 수업을 통해 감마파와 집중지표가 향상되는 경향을 보였고, 학업 성취도가 우수하지 못한 그룹의 학생들은 감마파와 집중지표의 변화에 일정한 경향성을 보이지 않았다. 이를 통해 학습자의 학업 능력을 고려한 수준별 프로그래밍 교육의 필요성을 제안하였다.

• 한국전자통신학회논문지
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• 제15권3호
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• pp.527-532
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• 2020

본 논문에서는 개인인증 시 활용 가능한 EEG 신호의 주파수 대역을 확인하기 위하여 뇌파 측정을 통해 분석한 결과를 제시하였다. 시각 과제의 유무에 따라 개안 상태와 폐안 상태로 구분하여 뇌파를 측정하였으며, 이를 델타파, 세타파, 알파파, SMR파, 중간베타파, 베타파 및 감마파의 7종류의 주파수 대역으로 나누어 시간에 따른 파워의 변동이 가장 작은 주파수 대역을 관찰하였다. 본 논문의 결과에서는 개안 상태와 폐안 상태에서는 유의한 차이가 나타나지 않았으나, 인간의 집중과 관련한 SMR파 및 중간베타파가 시간에 따른 파워의 변동이 가장 작게 관찰되었기에 재현성이 높은 주파수 대역인 것으로 나타났다.

• Nuclear Engineering and Technology
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• 제49권4호
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• pp.792-800
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• 2017

The essential requirement of a material to be used for engineering purposes at nuclear establishments is its ability to attenuate the most penetrating ionizing radiations, gamma $({\gamma})-rays$. Mostly, high-Z materials such as heavy concrete, lead, mercury, and their mixtures or alloys have been used in the construction of nuclear establishments and thus termed as nuclear engineering materials (NEM). The NEM are classified into two categories, namely opaque and transparent, depending on their behavior towards the visible spectrum of EM waves. The majority of NEM are opaque. By contrast, various types of glass, which are transparent to visible light, are necessary at certain places in the nuclear establishments. In the present study, ${\gamma}-ray$ shielding behaviors (GSB) of six glass samples (transparent NEM) were evaluated and compared with some opaque NEM in a wide range of energy (15 keV-15 MeV) and optical thickness (OT). The study was performed by computing various ${\gamma}-ray$ shielding parameters (GSP) such as the mass attenuation coefficient, equivalent atomic number, and buildup factor. A self-designed and validated computer-program, the buildup factor-tool, was used for various computations. It has been established that some glass samples show good GSB, thus can safely be used in the construction of nuclear establishments in conjunction with the opaque NEM as well.

• 천문학회지
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• 제37권5호
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• pp.465-470
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• 2004

I address the issue of nonthermal processes in the large scale structure of the universe. After reviewing the properties of cosmic shocks and their role as particle accelerators, I discuss the main observational results, from radio to $\gamma$-ray and describe the processes that are thought be responsible for the observed nonthermal emissions. Finally, I emphasize the important role of $\gamma$-ray astronomy for the progress in the field. Non detections at these photon energies have already allowed us important conclusions. Future observations will tell us more about the physics of the intracluster medium, shocks dissipation and CR acceleration.

• Biomolecules & Therapeutics
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• 제7권3호
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• pp.242-248
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• 1999

Diazepam, a benzodiazepine (BDZ) agonist, produces sedation and flumazenil, a BDZ antagonist, blocks these actions. The aim of this study was to examine the effects of BDZs on cortical electroencephalogram (EEG) in rats. The recording electrodes were implanted over the frontal and parietal cortices bilaterally, and the reference and ground electrodes over cerebellum under ketamine anesthesia. To assess the effects of diazepam and flumazenil, rats were injected with diazepam (1 mgHg, i.p.) and/or flumazenil ( 1 mg/kg, i.p.), and the EEG was recorded before and after drugs. Normal awake had theta peak in the spectrum and low amplitude waves, while normal sleep showed large amplitude of slow waves. The powers of delta, theta and alpha bands were increased during sleep compared with during awake. Diazepam reduced the mobility of the rat and induced sleep with intermittent fast spindles and large amplitude of slow activity, and it produced broad peak over betaL band and increased the power of gamma band, which were different from EEG patterns in normal sleep. Saline injection awakened rats and abolished fast spindles for a short period about 2-5 min from EEG pattern during diazepam-induced sleep. Flumazenil blocked both diazepam-induced sleep and decreased the slow activities of delta, theta, alpha and betaL, but not of gamma activity for about 10 min or more. This study may indicate that decrease in power of betaL and betaH bands can be used as the measure of central action of benzodiazepines, and that the EEG parameters of benzodiazepines have to be measured without control over the behavioral state by experimenter.