• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2001.05a
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• pp.156-161
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• 2001

본 연구에서는 45명의 가상현실 사용자들의 가상현실 전, 중, 후의 생리신호의 변화를 관찰하였고 성격, 능력 특성 설문지, 가상현실 평가 설문지를 이용하여 심리적 영향을 알아보았다. 체온의 변화 양상을 기준으로 하여 가상현실 사용자의 심리생리학적 유형을 나누고 유형별 심리적인 반응 특성을 살펴보았다. 1) A 유형: 가상현실 유행동안 체온이 연속적으로 감소하는 유형. 2) B 유형: 가상현실 윤행초기에 체온이 급격히 증가해서 운행동안 서서히 체온이 상승하는 유형. A 유형에 속하는 사용자들의 성격적 특성은 Holland의 성격 유형이론에 근거하여 실제형의 사람들이 많은 것으로 나타났으며 B 유형은 탐구형, 사회형의 사람들이 많은 경향으로 나타났다. 멀미민감도는 A 유형이 B 유형보다 더 크게 나타났다. A, B 유형의 뇌파분석 결과 정중 전두부 (Fz), 정중 중심부 (Cz)에서 베타파, 감마파 상대파워가 유의미한 차이가 있는 것으로 나타났다. 체온의 변화 양상에 따라 나눈 A, B 유형은 성격 및 능력 특성, 멀미민감도에 있어서 유형간 차이가 있는 것으로 나타났다.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.3
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• pp.177-183
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• 2003

Vibration analysis using component mode synthesis method was carried out to identify that to some extent each component contributed to the whole vibration of a powertrain consisting of several components. This analysis helped decide the component to be modified to reduce the powertrain weight, without degrading its current vibration characteristics. As a result, a cylinder block was chosen as a redesign object. Topology optimization analysis was performed to design the topology of the cylinder block whose flange connected with the transmission was chosen to be the design domain. After all, a new prototype of cylinder block was manufactured based on the analysis results for the verification experiment. It was confirmed from the analytical and experimental results that u optimally designed cylinder block had an advantage over the current one in the powertrain weight, with the powertrain vibration characteristics improved slightly.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1397-1398
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• 2015

본 연구에서는 뇌파를 이용하여 자동차에 HUD를 적용하였을 때, HUD의 위치와 이미지 컬러 변경 시 뇌 활성화 지수(Brain Activity Quotient)의 변화를 관찰하였다. 뇌파데이터는 Fp1, Fp2, O1, O2 총 4채널에서 얻었고, HUD위치는 좌측, 중앙, 우측으로 구성하였고 컬러는 초록, 주황, 빨강 총 3가지 색상을 사용하였다. HUD이미지의 크기는 $8{\times}4.5cm^2$로 구성하였다. 뇌 활성화 지수는 상대파워분석(Relative power analysis)를 사용하여 Slow beta wave(13~20 Hz)/alpha wave(4~7.99 Hz)로 계산하였다.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
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• 2002.11a
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• pp.103-109
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• 2002

본 연구에서는 가상현실사용자들이 모션베이스를 사용함에 따라 가상현실에 대한 평가가 어떻게 달라지는지를 조사하였다. 33명의 피험자를 대상으로 모션베이스 평가설문과 자기보고를 통해 가상현실에서의 현실감, 재미, 멀미감을 조사하고 가상주행 전, 중, 후에 내장근전위, 피부전도도, 말초체온, 말초혈류량, 심박률, 눈 깜박임의 생리신호를 측정, 분석함으로써 모션베이스 유무에 따른 심리·생리적인 변수들에서의 차이를 알아보았다. 모든 피험자는 2주 간격으로 모션베이스 사용조건과 모션베이스를 사용하지 않는 조건에서 두 번 가상현실을 경험하였다. 가상현실에 대한 현실감, 재미항목에서 모두 모션베이스를 사용한 조건이 높은 점수를 나타냈다. 또한 모션베이스를 사용한 조건에서 멀미보고수가 감소하는 경향이 나타났다. Tachyarrythmia의 상대파워 변화량과 PPG 최대진폭의 평균변화량 비교는 모션베이스를 사용한 가상현실 조건이 생리적인 요동을 적게 일으키는 것으로 나타났다. 이러한 결과들은 시각제시기와 동기화된 모션베이스를 도입함으로써, 가상현실에 대한 현실감은 높이면서 멀미감은 줄일 수 있다는 가능성을 보여준다.

• Journal of Power System Engineering
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• v.16 no.5
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• pp.20-25
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• 2012

오늘날 고속 철도는 중요한 교통수단으로 사용되고 있다. 주행거리 단축을 위해 직선 선로를 만드는 것이 불가피해 졌고 그에 따라 터널과 교량의 구간이 늘어나게 되었다. 특히 터널 통과 시에 발생되는 실내 소음은 운행 속도, 운행 구간 레일의 종류 등 여러 가지 원인에 의해 야기되어 진다. 실내소음으로 인해 철도를 이용하는 승객의 쾌적한 환경에 많은 영향을 미치게 된다. 이에 본 연구에서는 KTX와 새마을호의 터널 통과 시 발생되는 소음이 피험자에게 미치는 영향을 EEG를 통해 살펴보았다. 먼저 터널 통과 시 KTX와 새마을호의 실내 소음을 실제로 측정하여 크기, 주파수별로 분석하였다. 측정된 실내 소음을 피험자에게 제시하였을 때 나타나는 EEG를 측정하였다. EEG의 분석에 대해서는 불안, 긴장 등 스트레스를 받을 때 강하게 나타나는 ${\beta}$파의 변화를 관찰한 결과를 제시하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.235-237
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• 2004

어플리케이션 시스템을 사용하려는 사용자에 대한 인증에 관한 문제는 네트워크에 접근하고자 하는 사용자가 실제 의도한 상대인지를 판단하는 것으로써, 서버에서 서비스를 제공하기 전에 만족해야 할 필수적인 요구조건이다. 이와 관련한 많은 연구들이 진행되어 왔는데, 이 중에서 패스워드를 이용한 사용자인증 프로토콜은 여타의 방법에 비해 사용자에게 편리함을 제공할 뿐만 아니라 추가적인 하드웨어를 필요로 하지 않는 다는 장점을 가지고 있다. 최근에는 다중서버를 이용한 프로토콜이 제안되어 기존의 프로토콜 비해 보안이 강화된 서비스를 제공할 수 있게 되었다. 그러나 이 프로토콜은 다중서버를 사용함으로 인해서 부하가 많이 걸린다는 문제점이 존재한다. 본 논문에서는 이러한 다중서버를 이용한 프로토콜을 기반으로 하고 이에 타원곡선 알고리즘을 적용함으로써 컴퓨팅 파워를 줄일 수 있는 방안을 제시하고자 한다.

• Sleep Medicine and Psychophysiology
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• v.10 no.1
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• pp.52-60
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• 2003

Objectives: Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. The lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, utilization of simultaneous EEG and EOG processing and analyses to detect stage 1 sleep automatically were attempted. Methods: Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. A relative power of alpha waves less than 50% or relative power of theta waves more than 23% was regarded as stage 1 sleep. SEM(slow eye movement) was defined as the duration of both-eye movement ranging from 1.5 to 4 seconds, and was also regarded as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results were compared to the manual rating results done by two polysomnography experts. Results: A total of 169 epochs were analyzed. The agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3% and Cohen’s Kappa was 0.586 (p<0.01). A significant portion (32%) of automatically detected stage 1 sleep included SEM. Conclusion: Generally, digitally-scored sleep staging shows accuracy up to 70%. Considering potential difficulty in stage 1 sleep scoring, accuracy of 79.3% in this study seems to be strong enough. Simultaneous analysis of EOG differentiates this study from previous ones which mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnari remains a valid one in this study.

• Journal of Biomedical Engineering Research
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• v.25 no.1
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• pp.11-19
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• 2004

Stage 1 sleep provides important information regarding interpretation of nocturnal polysomnography, particularly sleep onset. It is a short transition period from wakeful consciousness to sleep. Lack of prominent sleep events characterizing stage 1 sleep is a major obstacle in automatic sleep stage scoring. In this study, we attempted to utilize simultaneous EEC and EOG processing and analyses to detect stage 1 sleep automatically. Relative powers of the alpha waves and the theta waves were calculated from spectral estimation. Either the relative power of alpha waves less than 50％ or the relative power of theta waves more than 23％ was regarded as stage 1 sleep. SEM (slow eye movement) was defined as the duration of both eye movement ranging from 1.5 to 4 seconds and regarded also as stage 1 sleep. If one of these three criteria was met, the epoch was regarded as stage 1 sleep. Results f ere compared to the manual rating results done by two polysomnography experts. Total of 169 epochs was analyzed. Agreement rate for stage 1 sleep between automatic detection and manual scoring was 79.3％ and Cohen's Kappa was 0.586 (p＜0.01). A significant portion (32％) of automatically detected stage 1 sleep included SEM. Generally, digitally-scored sleep s1aging shows the accuracy up to 70％. Considering potential difficulties in stage 1 sleep scoring, the accuracy of 79.3％ in this study seems to be robust enough. Simultaneous analysis of EOG provides differential value to the present study from previous oneswhich mainly depended on EEG analysis. The issue of close relationship between SEM and stage 1 sleep raised by Kinnariet at. remains to be a valid one in this study.

• Journal of Korean Society of Transportation
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• v.20 no.2
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• pp.17-26
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• 2002

Driver's psychophysiological load is one of the key measures for evaluating the safety of the highway. The purpose of this study is to propose and to test the methodology of evaluating the length limit of tangent section using driver's psychophysiological load. Driver's psychophysiological data is represented by the data acquire by frontal and occipital lobe. In order to compare the differences between tangent segments and the orders, real road driving experiments were performed. We collected psychophysiological data during the operation of vehicles. The experimental data were analyzed using FFT (Fast Fourier Transform) and relative power spectrum tools. These routine produces the beta value which is a major factor in consideration of driver's condition. The results in this study are summarized as follows: (1) A new methodology of evaluating the length limit in tangent section of highway using driver's psychophysiological load was proposed. (2) It was observed that driver's work load at tangent section was three times lower than that at the other section types. The beta value at tangent section is 2.219, while that at general section is 0.821. (3) It was observed that the driver's work load was significantly dropped to 0.428 after the continuous driving of 4.2km tangent section. (4) Based on the experimental subjects(from 27 Years to 31). we suggest that 30 times of design speed(3.0 km) could be acceptable as the length limit of tangent section in highway rather than the Previous limit which is 20 times of design speed(2.0km).

• Journal of Science Education
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• v.34 no.1
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• pp.113-123
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• 2010

The purpose of this study is to survey its characteristics through analyzing brain-wave activity in the scientifically-gifted and general children in the problem-solving process. The subjects of this study were 6 elementary school students, who are attending the institute of education for the gifted belonging to the regional office of education and 6 general children in the same region. The analysis was performed targeting total 12 people. As the task for measuring brain wave is Hanio tower, it is the effective task of researching into the problem-solving process. As the equipment of measuring brain wave is EEG System, it used equipment that was developed in Australia. The analysis of data was minimized noise. As a result of research, the gifted children are excellent in stable level compared to general people in a stable situation with opening the eyes, thereby being able to be known to be high in preparatory level for learning. This can be seen to be indicated as a result that the effect of learning is excellent due to being high in preparatory level for solving problem. Also, even in the process of performing task, the brain-activity level in the gifted children is high, thereby having been able to know that ${\alpha}-wave$ is formed that is significantly high in the regions of frontal lobe and occipital lobe. Accordingly, given developing task that is high in brain activity level of the gifted children, the higher educational effect will be able to be expected.