• 한국안전학회지
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• 제24권3호
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• pp.71-78
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• 2009

During a learning process, a human being is assumed to experience knowledge-based behaviors, rule-based behaviors, and skill-based behaviors sequentially if Rasmussen was right. If any psycho-physiological symptom to those different levels can be obtained, it can be useful as a measure whether a human being is fully trained and has gotten a skill in his work. Therefore, this study aimed to draw relationships between human performance measures and psycho-physiological measures while committing a computer-simulated pointing task by utilizing the power spectrum technique of EEG data, especially with the ratio of relative beta-to-alpha band power. The result showed that, during correct responses, the ratio came to stabilize as all the performance data went stable. However, response time was not a simple linear function of task difficulty level only, but a joint function of task characteristics as well as behavior levels. Comparing relative band power ratios from errors and correct responses, activated states of one's brain could be explained, and characteristics of the task could understood. To tell that of pointing task, correlations around C3, C4, P3, P4 and 01, 02 area were significant and high in correct response cases whereas most correlation coefficients went down in error cases standing for imbalance of psycho-motor functions. Though task difficulty was the only one factor that could influence on relative band power ratio with statistical significance, it should be comprehended to mean a different way of expression indicating task characteristics since at least error-some situation could be explained with the help of relative band power ratio that absolute band power failed.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1260-1274
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• 2016

To obtain good summarization algorithms, we need first understand how people summarize videos. 'Semantic gap' refers to the gap between semantics implied in video summarization algorithms and what people actually infer from watching videos. We hypothesized that ERP responses to real time videos will show either N400 effects to topic-irrelevant shots in the 300∼500ms time-range after stimulus on-set or P600 effects to topic-relevant shots in the 500∼700ms time range. We recruited 32 participants in the EEG experiment, asking them to focus on the topic of short videos and to memorize relevant shots to the topic of the video. After analysing real time videos based on the participants' rating information, we obtained the following t-test result, showing N400 effects on PF1, F7, F3, C3, Cz, T7, and FT7 positions on the left and central hemisphere, and P600 effects on PF1, C3, Cz, and FCz on the left and central hemisphere and C4, FC4, P8, and TP8 on the right. A further 3-way MANOVA test with repeated measures of topic-relevance, hemisphere, and electrode positions showed significant interaction effects, implying that the left hemisphere at central, frontal, and pre-frontal positions were sensitive in detecting topic-relevant shots while watching real time videos.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1812-1824
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• 2016

The neural dynamics underlying the causal network during motor planning or imagery in the human brain are not well understood. The lack of signal processing tools suitable for the analysis of nonlinear and nonstationary electroencephalographic (EEG) hinders such analyses. In this study, noise-assisted multivariate empirical mode decomposition (NA-MEMD) is used to estimate the causal inference in the frequency domain, i.e., partial directed coherence (PDC). Natural and intrinsic oscillations corresponding to the motor imagery tasks can be extracted due to the data-driven approach of NA-MEMD, which does not employ predefined basis functions. Simulations based on synthetic data with a time delay between two signals demonstrated that NA-MEMD was the optimal method for estimating the delay between two signals. Furthermore, classification analysis of the motor imagery responses of 29 subjects revealed that NA-MEMD is a prerequisite process for estimating the causal network across multichannel EEG data during mental tasks.

• 감성과학
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• 제2권2호
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• pp.1-10
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• 1999

본 연구의 목적은 중추신경계 반응과 자율신경계 반응을 이용하여 향이 인간에 미치는 영향을 평가하고자 하는 것이다. 본 연구는 20-26세의 남자 10명, 여자 10명으로 구성된 피험자를 대상으로 이루어졌고, 100% Rose oil bulgrian, Lemon oil misitano, Jasmine abs., Lavender oil france (KIMEX.co.ltd) 등 4가지의 향을 사용하여 실험을 수행하였다. 전두엽 (Fz)과 두정엽 (Cz)에서 EEG를 기록하여 대역별 relative power spectrum 값을 구하고 $\alpha$대역에 대한 $\beta$대역의 비($\beta$/$\alpha$)를 통하여 향에 대한 감성 평가를 시도하였다. 또한 자율신경계 반응은 심전도, 피부온도, 피부저항의 생리신호를 측정하였다. 주관적 평가는 향의 세부적인 이미지를 나타내는 후각 감성 형용사를 이용하여, 양극의 7점 척도 25문항, 단극의 5점 척도 40문항, 그리고 각 향의 전반적인 선호도를 묻는 양극의 7점 척도 2문항으로 구성하여 자극제시 전, 후에 각각 실시하였다. 전체적으로 피험자들은 Lemon을 가장 쾌하고 연하다는 평가를, Rose를 가장 불쾌하며 진하다고 평가하였다. $\beta$/$\alpha$의 비는 쾌하고 연할수록 감소하였고 불쾌하고 진할수록 증가하였다. 또한 심박 변화율과 피부온도는 쾌하고 연할수록 감소하였고, 불쾌할수록 반대 결과를 나타내었다. 결론적으로 쾌하고 연한 향과 불쾌하고 진한 향 사이에 $\beta$/$\alpha$의 비와 자율 신경계 반응의 차이를 관찰할 수 있었다.

• Journal of Computing Science and Engineering
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• 제7권2호
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• pp.112-121
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• 2013

The last years have seen a rise of interest in using electroencephalography-based brain computer interfacing methodology for investigating non-medical questions, beyond the purpose of communication and control. One of these novel applications is to examine how signal quality is being processed neurally, which is of particular interest for industry, besides providing neuroscientific insights. As for most behavioral experiments in the neurosciences, the assessment of a given stimulus by a subject is required. Based on an EEG study on speech quality of phonemes, we will first discuss the information contained in the neural correlate of this judgement. Typically, this is done by analyzing the data along behavioral responses/labels. However, participants in such complex experiments often guess at the threshold of perception. This leads to labels that are only partly correct, and oftentimes random, which is a problematic scenario for using supervised learning. Therefore, we propose a novel supervised-unsupervised learning scheme, which aims to differentiate true labels from random ones in a data-driven way. We show that this approach provides a more crisp view of the brain states that experimenters are looking for, besides discovering additional brain states to which the classical analysis is blind.

• The Journal of Asian Finance, Economics and Business
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• 제6권4호
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• pp.159-170
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• 2019

The paper aims to understand the mediating effect of Country Image (CI) on the relationship between consumer cosmopolitanism and consumers' purchase, visit and investment intentions towards a foreign country, considering the moderating effects of ethnocentrism, materialism, product familiarity, and visits to a country in a global market. The study extends research on the global and local consumption by simultaneously analysing the influence of country image dimensions and several moderating effects on consumers' behavioural intentions. Four hundred and fifty-seven valid responses from international consumers were collected through a questionnaire measuring country image dimensions. Findings indicate that cosmopolitanism has a significant and positive effect on foreign consumers' behavioural intentions and country image dimensions mediate this relationship. Moreover, a moderating effect was found for ethnocentrism, materialism, product familiarity, and visits to a country on the relationship between country cognitions and the intentions to visit the country. This study shows the importance of considering cosmopolitanism as a potential segmentation variable in international markets. The results can help managers and policymakers to better understand the image that foreign consumers hold about Portugal, their intentions to buy or invest in the country, as well as to think of Portugal as a tourism destination.

• 설비공학논문집
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• 제10권6호
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• pp.721-731
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• 1998

Recently, many researchers are studying the relation between thermal environment and human comfort. The purpose of this study was to obtain basic data which are necessary to determine the thermal comfort sensation and physiological responses for men in winter indoor environment. From January to February 1998, subject experiment was 40 times proceeded under twenty different conditions of air temperature and relative humidity with early-twenty male university students. We examined subjective evaluation, Electrocardiogram(ECG), Electroencephalogram(EEG) of subjects. The results of this study can be summarized as follows : The comfort zone of people in winter was achieved at Standard new effective temperature($SET^*$) $ 25.2^{\circ}C$, PMV range was obtained by Fanger's statistical calculation was －0.27＜PMV＜＋0.62, TSV range obtained subjects vote was －0.76＜TSV＜＋0.36. The largest difference of skin temperature was found at the calf area as air temperature changes. vote rate of human body presented calflongrightarrowheadlongrightarrowforearmlongrightarrowchestlongrightarrowabdo men in turn. Heart rate was decreased at low $SET^*$ and heart rate was increased at high $SET^*$ But there was no change at EEG.

• 대한인간공학회지
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• 제21권3호
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• pp.35-46
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• 2002

In this study, emotion changes were induced by four imaginations- pleasantness, unpleasantness, arousal, relaxation and it was examined using subjective evaluation and analysis of the physiological signals of the central and autonomic nerve systems whether the intended emotions were appropriately achieved, and whether these emotion changes could be distinguished from the analysis of physiological signals. Each of the four imaginations was implemented on 32 subjects for 30 seconds, while that Electroencephalogram (EEG), Eelectrocardiogram (RSP) were measured, and a subjective evaluation was implemented following the completion of the measurement. The analysis of the subjective evaluation revealed that the subjects underwent the four clearly differentiated imaginations, and the pleasantness level was classified into four imagination stages, pleasantness>relaxation>arousal=comfort>unpleasantness, and arousal level was classified into four imagination stages in the order of arousal>unpleasantness${\approx}$pleasantness>comfort>relaxation. The analysis of the EEG revealed that three stages of pleasantness level, pleasantness>relaxation=arousal=comfort>unpleasantness were classified from the values of ${\alpha}/{\alpha}+{\beta}\;and\;{\beta}/{\alpha}+{\beta}$, and about tour distinguishable stages of arousal level were obtained from the autonomic nervous system responses following the order of arousal>unpleasantness${\approx}$pleasantness> comfort> relaxation. It was found that intended emotion could be induced from the imagination, and these induced emotion changes could be differentiated using the physiological signals of the EEG and autonomic nervous system.

• 한국안전학회지
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• 제29권1호
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• pp.47-53
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• 2014

The application of advanced Main Control Room(MCR) is accompanied with lots of changes and different forms and features through the virtue of new digital technologies. The characteristics of these digital technologies and devices give many opportunities to the interface management, and can be integrated into a compact single workstation in advanced MCR so that workers can operate the plant with minimum physical burden under any operation conditions. However, these devices may introduce new types of human errors and thus a means to evaluate and prevent such errors is needed, especially those related to characteristics of digital devices. This paper reviewed the new type of human error hazards of tasks based on digital devices and surveyed researches on physiological assessment related to human error. An experiment was performed to verify human error hazards by physiological responses such as EEG which was measured to evaluate the cognitive workload of operators. And also, the performances of four tasks which are representative in human error hazard tasks based on digital devices were compared. Response time, ${\beta}$ power spectrum rate of each task by EEG, and mental workload by NASA-TLX were evaluated. In the results of the experiment, the rate of the ${\beta}$ power was increased in the task 1 and task 4 which are searching and navigating task and memory task of hierarchical information, respectively. In case of the mental workload, in most of evaluation items, task 1 and 4 were highly rated comparatively. In this paper, human error hazards might be identified by highly cognitive workload. Conclusively, it was concluded that the predictive method which is utilized in this paper and an experimental verification can be used to ensure the safety when applying the digital devices in Nuclear Power Plants (NPPs).

• 감성과학
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• 제17권3호
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• pp.29-38
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• 2014

본 연구에서는 LED 면조명을 이용한 감성조명시스템의 인체 생리학적 반응을 검증하였다. 실험은 시각 질환이 없는 건강한 20대 남성 10명을 대상으로 LED 면조명의 색상에 따른 인체의 반응을 평가하였다. LED 조명은 빨간색, 주황색, 노란색, 초록색, 파란색, 보라색, 무채색(하얀색)을 사용하여 5분간 조명 자극을 주었다. 평가 방법으로 심리적 상태를 분석하기 위하여 뇌파와 심박변이도를 평가하였고 피부의 온도 변화를 살펴보기 위해 체열을 평가하였다. 분석 결과 뇌파의 경우 무채색, 빨간색, 주황색 LED 면조명 자극 시 ${\alpha}$파 비율이 감소하였다. 또한 무채색, 빨간색, 주황색, 노란색 LED 면조명 자극을 받을 때 부교감신경에 비하여 교감신경이 활성화되고, 체열이 증가하였다. 이에 비해 초록색, 파란색, 보라색 LED 면조명 자극을 받을 때에는 ${\alpha}$파 비율의 증가와 교감신경에 비하여 부교감신경의 활성화가 발생하였고 체열이 감소하였다. 향후 각 색상을 조합하여 상황별 모드를 구성한 실험과 시각적 자극 외에 아로마와 같은 후각 자극, 음악과 자연의 소리를 이용한 청각 자극 등을 이용한 복합한 시너지 효과에 대한 연구가 필요할 것으로 사료된다.