• 한국의학물리학회지:의학물리
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• 제5권2호
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• pp.69-76
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• 1994

수면의 방해는 대부분의 소음 연구에서 고려되는 여러 요소 중의 하나이다. 수면동안 소음에 노출 되었을 때 수면 단계에 따른 일반적 인간의 응답이 조사되었다. 그리고 깊은 수면율과 잠을 깨는 비율에 대한 연속적인 교통 소음의 효과가 연구되었다.

• 한국멀티미디어학회논문지
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• 제22권12호
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• pp.1491-1499
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• 2019

Insufficient sleep time and bad sleep quality causes many illnesses and it's research became more and more important. The most common method for measuring sleep quality is the polysomnography(PSG). The PSG is a test used to diagnose sleep disorders. The most common PSG data is obtained from the examiner, which attaches several sensors on a body and takes sleep overnight. However, most of the sleep stage classification in PSG are low accuracy of the classification. In this paper, we have studied algorithm for sleep level classification based on machine learning which can replace PSG. EEG, EOG, and EMG channel signals are studied and tested by using CNN algorithm. In order to compensate the performance, a mixed model using both CNN and DNN models is designed and tested for performance.

• 설비공학논문집
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• 제19권4호
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• pp.307-312
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• 2007

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of sleep efficiency and MST under four thermals conditions ($22^{\circ}C,\;24^{\circ}C,\;26^{\circ}C,\;30^{\circ}C$). Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. Their age was from 20 to 22 years old. They were healthy, and had regular sleep with consistent bed and wakeup time. It was checked whether they had a good sleep before the night of experiment. Experiments were performed in an environmental chamber using thermo-hygrostat. The physiological signal (EEG) for sleep stage were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, mean skin temperature for comfort sleeping was $34.5{\sim}35.4^{\circ}C$. Considering sleep efficiency and mean skin temperature, indoor room temperature of upper limit was $28.1^{\circ}C$.

• 설비공학논문집
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• 제18권7호
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• pp.535-540
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• 2006

This study was performed In evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of Physiological signals under variations in thermal conditions. Five female subjects who have similar life cycle and sleep patterns were participated for the sleep experiment. It was checked whether they had a good sleep before the night of experiment. EEGs were obtained from C3-A2 and C4-A1 electrode sites and EOGs were acquired from LOC (left outer canthus) and ROC (right outer canthus) for REM sleep detection. Sleep stages were classified, then TST (total sleep time), SWS (slow wave sleep) latency and SWS/TST were calculated for the evaluation of sleep efficiencies on thermal conditions. TST was defined as an amount of time from sleep stage 1 to wakeup. SWS latency was from light off time to sleep stage 3 and percentage of SWS over TST was calculated for the evaluation of sleep quality and comfort sleep under thermal conditions. As result, the condition which raise a room temperature provided comfortable sleep.

• 한국멀티미디어학회논문지
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• 제17권2호
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• pp.113-123
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• 2014

Electrophysiological recordings are considered a reliable method of assessing a person's alertness. Sleep medicine is asked to offer objective methods to measure daytime alertness, tiredness and sleepiness. As EEG signals are non-stationary, the conventional method of frequency analysis is not highly successful in recognition of alertness level. In this paper, EEG signals have been analyzed using wavelet transform as well as discrete wavelet transform and classification using statistical classifiers such as euclidean and mahalanobis distance classifiers and a promising method SVM (Support Vector Machine). As a result of simulation, the average values of accuracies for the Linear Discriminant Analysis (LDA)-Quadratic, k-Nearest Neighbors (k-NN)-Euclidean, and Linear SVM were 48%, 34.2%, and 86%, respectively. The experimental results show that SVM classification method offer the better performance for reliable classification of the EEG signal in comparison with the other classification methods.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.493-493
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• 2000

Multi-valued decision making for transitional stochastic events was newly derived based on conditional probability of database. The two values (on-off) decision making method without transition had been proposed by one of the author in a previous work for a purpose of realizing human on-off decision making. The current method is an extension of the previous on-off decision making. By combining the conditional probability and the transitional probability, the closed form of the algorithm for the multi-valued transitional decision making was derived. The proposed multi-valued decision making was successfully applied to the determination of the five levels of the vigilance of a subject during the EEG recording; awake stage, drowsy stage and sleeping stages (stage 1, stage 2/3, REM (rapid eye movement)). The method for determining the vigilance level can be directly usable for the two purposes; selection of awake EEG segments for automatic EEG interpretation, and determination of sleep stages through sleep EEG. The proposed multi-valued decision making with a mathematical background of the probability can be applicable widely, in industries and in medical fields for purposes of the multi-valued decision making.

• 수면정신생리
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• 제3권2호
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• pp.43-55
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• 1996

Since REM sleep was found to be closely related with dream, efforts have been made to find the neurophysiological mechanism and the psychological meaning of dream. However, since most researchers have paid attention to dreams of adults, there are relatively few studies devoted to those of developing children. In the prevent study, we reviewed the previous studies and hypotheses about sleep and dream in various aspects and summarized the characteristics of sleep and dream of children in developmental domain as followings. (1) Sleep development : Across childhood, sleep architecture and sleep-wakefulness cycles are progressively changed toward the patterns of adult. They become similar to adult patterns only in their adolescence. Thus, the sleep event sconsidered as abnormal in adults may be normal in children. (2) Dream development : First, the content and meaning of the dream change with increasing age and develop in parallel with children's ego function, especially cognitive developmental stages. Second, for the children, the reality and the dream are on the continuous spectrum of 'reality-imitation-play-fantasy-dream'. Third, dreaming is the pure assimilation process for the children and through dreaming they can adapt and accomodate the reality without emotion.

• 수면정신생리
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• 제15권1호
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• pp.5-11
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• 2008

Sleep is an essential process maintaining the life cycle of the human. In parallel with physiological, cognitive, subjective, and behavioral changes that take place during the sleep, there are remarkable changes in the electroencephalogram (EEG) that reflect the underlying electro-physiological activity of the brain. However, analyzing EEG and relating the results to clinical observations is often very hard due to the complexity and a huge data amount. In this article, I introduce several linear and non-linear tools, developed to analyze a huge time series data in many scientific researches, and apply them to EEG to characterize various sleep states. In particular, the spectral analysis, detrended fluctuation analysis (DFA), and synchrony analysis are administered to EEG recorded during nocturnal polysomnography (NPSG) processes and daytime multiple sleep latency tests (MSLT). I report that 1) sleep stages could be differentiated by the spectral analysis and the DFA ; 2) the gradual transition from Wake to Sleep during the sleep onset could be illustrated by the spectral analysis and the DFA ; 3) electrophysiological properties of narcolepsy could be characterized by the DFA ; 4) hypnic jerks (sleep starts) could be quantified by the synchrony analysis.

• 생명과학회지
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• 제12권4호
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• pp.375-382
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• 2002

운동이 수면에 미치는 효과를 보다 명확하게 검증하기 위해 일반상태가 아닌 카페인으로 인한 수면장애 상태에서 운동의 효과를 조사하였다. 본 연구의 피험자는 3회의 실험 조건(1. 평상시, 2. 카페인 섭취, 3. 카페인섭취 $\times$운동)에 참여해서 이들의 수면변수와 수면시 뇌파를 측정하였다. 카페인은 고용량으로 1200mg(400mg$\times$3)을 투여하였으며, 운동강도는 60% V $O_{2peak}$에서 60분을 사이클 에르고미터를 이용해 실시하였다. 본 실험결과 카페인 섭취로 입면시간 연장과 수면효율성 감소 그리고 서파수면(SWS)의 감소로 수면에 불리한 효과를 유발시켰다. 하지만 카페인 섭취와 운동을 병행했을 때 카페인 투여시 발생된 효과를 상쇄시키는 효과가 나타났다. 이러한 결과로써 고용량의 카페인 섭취가 수면장애 유발 효과가 있었지만 운동을 병행해서 실시했을 때 수면촉진과 수면효율성 그리고 숙면인 서파수면의 증가가 나타남으로써 운동이 수면방해를 완화시키고 수면 향상에 효과가 있는 것으로 생각된다.

• The Korean Journal of Physiology and Pharmacology
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• 제14권5호
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• pp.291-297
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• 2010

The sleep homeostatic response significantly affects the state of anesthesia. In addition, sleep recovery may occur during anesthesia, either via a natural sleep-like process to occur or via a direct restorative effect. Little is known about the effects of isoflurane anesthesia on sleep homeostasis. We investigated whether 1) isoflurane anesthesia could provide a sleep-like process, and 2) the depth of anesthesia could differently affect the post-anesthesia sleep response. Nine rats were treated for 2 hours with $ad$ $libitum$ sleep (Control), sleep deprivation (SD), and isoflurane anesthesia with delta-wave- predominant state (ISO-1) or burst suppression pattern-predominant state (ISO-2) with at least a 1-week interval. Electroencephalogram and electromyogram were recorded and sleep-wake architecture was evaluated for 4 hours after each treatment. In the post-treatment period, the duration of transition to slow-wave-sleep decreased but slow wave sleep (SWS) increased in the SD group, but no sleep stages were significantly changed in ISO-1 and ISO-2 groups compared to Control. Different levels of anesthesia did not significantly affect the post-anesthesia sleep responses, but the deep level of anesthesia significantly delayed the latency to sleep compared to Control. The present results indicate that a natural sleep-like process likely occurs during isoflurane anesthesia and that the post-anesthesia sleep response occurs irrespective to the level of anesthesia.