• Korean Journal of Cognitive Science
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• v.33 no.1
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• pp.51-75
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• 2022

Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation that is able to alter neuronal activity in particular brain regions. Many studies have researched how tDCS modulates neuronal activity and reorganizes neural networks. However it is difficult to conclude the effect of brain stimulation because the studies are heterogeneous with respect to the stimulation parameter as well as individual difference. It is not fully in agreement with the effects of brain stimulation. In particular few studies have researched the reason of variability of brain stimulation in response to time so far. The study investigated individual variability of brain stimulation based on circadian rhythm and chronotype. Participants were divided into two groups which are morning type and evening type. The experiment was conducted by Zoom meeting which is video meeting programs. Participants were sent experiment tool which are Muse(EEG device), tdcs device, cell phone and cell phone holder after manuals for experimental equipment were explained. Participants were required to make a phone in frount of a camera so that experimenter can monitor online EEG data. Two participants who was difficult to use experimental devices experimented in a laboratory setting where experimenter set up devices. For all participants the accuracy of 98% was achieved by SVM using leave one out cross validation in classification in the the effects of morning stimulation and the evening stimulation. For morning type, the accuracy of 92% and 96% was achieved in classification in the morning stimulation and the evening stimulation. For evening type, it was 94% accuracy in classification for the effect of brain stimulation in the morning and the evening. Feature importance was different both in classification in the morning stimulation and the evening stimulation for morning type and evening type. Results indicated that the effect of brain stimulation can be explained with brain state and trait. Our study results noted that the tDCS protocol for target state is manipulated by individual differences as well as target state.

• Sleep Medicine and Psychophysiology
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• v.25 no.1
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• pp.21-26
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• 2018

Objectives: The current study aims to develop Korean Social Affective Visual Stimuli (K-SAVS) to arouse social affect. Methods: K-SAVS is composed of pictures of social situations among East Asians. Each picture contains a negative, positive, or neutral affect. Positive and negative stimuli were presented to one group of subjects. Negative and neutral stimuli were presented to another group of subjects. All subjects were required to fill out Affective Valence and Arousal Manikin. Results: In the initial test, 18 positive affective stimuli pictures (1 set) and 36 negative affective stimuli pictures (2 sets) were chosen from 95 stimuli pictures. Positive affective stimuli pictures showed higher valence (p < 0.001) and lower arousal (p < 0.001) than negative affective stimuli pictures. In the confirmatory test, 18 neutral stimuli pictures (1 set) were additionally selected out of the total of 79 pictures of neutral stimuli pictures and the pictures used in the former experiment. Neutral stimuli pictures showed higher valence (p < 0.001) and lower arousal (p < 0.001) than negative affective stimuli pictures. Conclusion: K-SAVS can be a valid and useful tool for inducing specific social affects of Koreans.

• The Journal of Korean Academy of Sensory Integration
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• v.7 no.2
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• pp.63-76
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• 2009

Objective : The purpose of this study was to identify effects of intensive sensory integration (SI) treatment and home-program for a child who has a sensory integration disorder. This study also examined whether the positive effect is long-lasting by a follow-up test. Method : A boy with sensory integration dysfunction underwent an intensive SI treatment for 2 weeks. The intervention was consisted of 9 sessions and duration of the each session was 40 minutes. Sensory diet and Wilbarger protocol was provided as home program. The child's sensory function was evaluated before and after the SI intervention. Five month later, re-evaluation was executed for follow-up purpose. Results : In the evaluation after the Si intervention, the child's sensory defensiveness was decreased. Praxis, visual perception, sensory regulation dysfunction (sleep function), affective stabilization and performance of activities of daily living are also improved. In the re-evaluation after the 5 month later, the self-regulation ability, especially sleep function, has been maintained and the visual perception was developing continually. However, the child showed some affective regulation such as bothering his mother and losing his temper. Conclusions : The intensive SI intervention showed positive effects in terms of SI function improvement and the effect lasted long without any additional therapeutic intervention.

• Sleep Medicine and Psychophysiology
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• v.18 no.1
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• pp.35-39
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• 2011

Objective: Diurnal preference is an attribute reflecting whether people are alert and preferring to be active either early or late in the day. It also referred to as chronotype or morningness-eveningness trait. The PER3 genes have been known to influence diurnal preference. In this study, we have investigated the associations between the PER3 gene polymorphisms and diurnal preference in a healthy young population, controlling for the social and environmental confounding factors. Methods: The participants in this experiment included 299 unrelated medical college students (M=191, F=108), with a mean age of 22.9 years. Diurnal preference was measured by a single administration of the 13-item Composite Scale for Morningness (CSM). Genotyping of the PER3 VNTR (rs57875989) was performed using polymerase chain reaction. A two-tailed alpha of 0.05 was chosen. Results: The mean${\pm}$SD score on the CSM scale for all subjects was 31.90${\pm}$6.39. There was no significant difference in total CSM score between gender groups, although females showed a trend towards higher morningness score. Although PER3 5R/5R showed the tendency towards high CSM scores, there were no significant differences on CSM scores among genotypes and allele status of PER3 VNTR (rs57875989). Conclusions: We could not confirm that the PER3 VNTR is associated with diurnal preference in a Korean healthy young population. The future studies need to investigate the association between diurnal preference and other polymorphisms of PER3 gene in larger sample of Korean young healthy population.

• Journal of Physiology & Pathology in Korean Medicine
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• v.31 no.2
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• pp.83-93
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• 2017

This study covers pattern differentiation based on Korean medical references, research trend and modern clinical applications about Sleep-Wake disorders of Diagnostic and Statistical Manual of Mental Disorders(DSM-V) published by American Psychiatric Association. Insomnia disorder is mostly caused by yin deficiency of liver-kidney or liver qi depression and main patterns are heart-kidney non-interaction, deficiency-excess complex pattern containing phlegm-heat due to qi stagnation and blood stasis. Hypersomnolence disorder is more due to yang deficiency rather than yin deficiency and it's major pattern is spleen-kidney yang deficiency. Cataplexy is main feature in narcolepsy and corresponds to depressive psychosis or fainting in terms of Korean Medicine and narcolepsy is assumed to be relevant to liver wind. Breathing-related sleep disorders are related with phlegm-fluid retention brought on spleen deficiency with dampness encumbrance. Pattern of circadian rhythm sleep-wake disorders is combined with yin deficiency of liver-kidney or liver qi depression of insomnia disorder and spleen-kidney yang deficiency or dampness-phlegm of hypersomnolence disorder. Yin deficiency with effulgent fire brought on drugs or alcohol is one of main patterns of substance/medication-induced sleep disorder and combined patterns with yin deficiency of liver-kidney and blood stasis or dampness-phlegm-heat are mostly applied clinically. This study drew major and frequently applied patterns of sleep-wake disorders based on Koran medical literature and modern clinical applications. And that can be the groundwork for the task ahead like clinical practice guideline of sleep-wake disorders containing pattern differentiation, diagnosis and prescriptions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.5
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• pp.2225-2233
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• 2013

This study was designed to identify the extent of incident shock who are in high risk of post traumatic shock stress, and analyze the related factors that affect the extent of incident shock. The subjects are 415 rescue workers from Seoul Metropolitan Fire & Disaster Headquarters, who are in high frequency of fire outbreaks and rescue mobilization. With a reliability of Cronbach's ${\alpha}$=.975, the results show invasion, avoidance, sleep disorder and emotional paralysis, dissociative symptom, hyper arousal as foremost causes respectively. Moreover, the results imply that the extent of incident shock was higher in people with more age or being married. Also, from the occupational perspective, the number of years as fire fighters, as rescue workers, mobilization and experiences at work in proportion to incident shocks has risen exponentially. It is notable that the groups who alleviate stress by consuming liquors had higher extent of incident shock. In conclusion, to deal with groups in high risk, management system and prevention care programs for incident shocks need to be introduced immediately and put into effect.

• Journal of Korean Institute of Industrial Engineers
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• v.30 no.3
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• pp.181-189
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• 2004

The purpose of this study was to investigate the effects of sleep/wake behavior for shift workers in the iron and steel industry using wrist actigraph for 59 male workers on a continuous full-day three-team three-shift system of backward rotation including on-duty and off-duty periods. The wrist actigraph data were recorded for 15 days (l shift cycle) for each subject. The sleep length at home during night shift decreased significantly as compared to the morning or evening shifts. The night shift nap length increased significantly in all sections as compared to the morning or evening shifts. The nap length in the Steel Manufacturing Process and Rolling Process during night shift decreased significantly as compared to the Machine Maintenance Section, the Forwarding of Products Section, and the Field Management Section. However, the sleep length at home while off-duty period increased significantly. The percentage of nap length during night shift in the Rolling Process, Steel Manufacture Process, and the other three types of jobs was 16.0%, 20.4%, and about 50.0%, respectively. The nap length during night shift for the above 50 year olds increased significantly as compared to the below 50 year olds. Finally, we discussed the role of nap-taking during the burden on night shift workers and the increased difficulty in continuing their job.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.2
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• pp.75-80
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• 2020

There are so many low power MAC protocols for wireless sensor network. IEEE802.15.4 among them has disadvantage of a large power consumption for synchronization. To save power consumption it use the superframe operation alternating sleep mode and awake mode. But latency is longer result from superframe operation. B-MAC can have shorter latency according to check interval. But transmitter consumes more power because of long preamble. And receiver is suffering from overhearing. In this paper, we use the adaptive check interval scheme[1] of B-MAC for enhancing the power consumption. Its maximum throughput and minimum delay is evaluated by comparing the proposed scheme with a typical single channel IEEE802.15.4.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.5
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• pp.1154-1161
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• 2005

Yin Yang theory is the first and the last one to interpret diseases apply to treatment in oriental medicine. So it is regarded as the way of heaven and earth, the discipline of all things, the origin of change, the beginning of giving birth and death, the source of spirit. These regulatory passages are needed to compare with western medical physiology and analyzed whether it has scientific bases or not. The Yin Yang theory of traditional oriental medicine are summerized from the descriptions of Scripture of Documents, Ying Wei theory of Huangdi Neijing. Meanwhile up-to-date neurobiological and molecular genetic theories on circadian physiology are reviewed in western medicine. Sunshine is transferred through RGC to SCN, herein the central circadian rhythm is made by zeitgeber and interaction of melatonin secreted from pineal body and orexin from mp pan of hypothalamus. So HPA axis is activated and controlled under the circadian rhythm and affects peripheral tissues and cells of whole body through glucocorticoid hormones. First of all, the circadian rhythm makes the basic patterns of human life in biological and sociological meaning. It is almost same context with the record of the Scripture of Documents. Also the Ying Qi and Wei Qi is basically same with the sleep-awake mechanism, that is melatonin/orexin signal or per/clk/bmal/cry genes with circadian activation and activity of each organ's physiological function. Conclusively it can be said that Yin Yang is a priori principle of living things and the beginning of giving birth and death for activation of them biologically, as is described in Huangdi Neijing.

• Journal of the Institute of Convergence Signal Processing
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• v.13 no.3
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• pp.136-141
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• 2012

One of the main reasons for serious road accidents is driving while drowsy. For this reason, drowsiness detection and warning system for drivers has recently become a very important issue. Monitoring physiological signals provides the possibility of detecting features of drowsiness and fatigue of drivers. One of the effective signals is to measure electroencephalogram (EEG) signals and electrooculogram (EOG) signals. The aim of this study is to extract drowsiness-related features from a set of EEG signals and to classify the features into three states: alertness, drowsiness, sleepiness. This paper proposes a neural-network-based drowsiness detection system using Linear Predictive Coding (LPC) coefficients as feature vectors and Multi-Layer Perceptron (MLP) as a classifier. Samples of EEG data from each predefined state were used to train the MLP program by using the proposed feature extraction algorithms. The trained MLP program was tested on unclassified EEG data and subsequently reviewed according to manual classification. The classification rate of the proposed system is over 96.5% for only very small number of samples (250ms, 64 samples). Therefore, it can be applied to real driving incident situation that can occur for a split second.