• Proceedings of the Korean Operations and Management Science Society Conference
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• 2007.11a
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• pp.195-203
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• 2007

In this paper, an analytic model of sleep model operation in the IEEE 802.16e is investigated. A mobile subscribe. station (MSS) goes to sleep mode after negotiations with the base station (BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/1 with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Food Science and Biotechnology
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• v.27 no.6
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• pp.1833-1842
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• 2018

The aim of this study was to identify sleep-promoting substance from Polygonatum sibiricum rhizome extract (PSE) with the regulation of sleep architecture. PSE showed a decrease in sleep latency time and an increase in the sleeping time. In the electroencephalography analysis of rats, PSE (150 mg/kg) showed an increase of non-rapid eye movement by 38% and a decrease of rapid eye movement by 31% compared to the control. This sleep-promoting activity was found to be involved in the $GABA_A$-BDZ receptor. The chemical structure of the pure compound was determined by the $^1H$ and $^{13}C$ nuclear magnetic resonance spectroscopy and gas chromatography mass spectrometry analysis; active compound was glyceryl-1-monolinoleate. The commercial standard glyceryl-1-monolinoleate showed a similar inhibitory concentration on [$^3H$]-flumazenil binding to $GABA_A$-BDZ receptors with final active fraction of PSE. The results indicate that glyceryl-1-monolinoleate is a major active compound responsible for the PSE-derived sleep promotion.

• Journal of Korean Biological Nursing Science
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• v.16 no.4
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• pp.309-317
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• 2014

Purpose: The purpose of this study was to understand sleep circadian rhythm and sleep quality between normal-weight and obese group according to Body Mass Index to develop education and nursing intervention programs for the obese. Methods: This study involved 186 subjects who visited at S hospital obesity clinic, K province. They were divided into 2 groups: normal-weight group 91 and obese group 95. Data were collected from October 18th to November 12th in 2013. Data were analyzed with frequency, percentage, ${\chi}^2$-test, Mann-Whitney U test, ANCOVA, t-test and ANOVA with using SPSS version 20.0. Results: The results showed that morning type 1.1%, middle type 91.2% and evening type 7.7% of sleep circadian rhythm in normal-weight group and middle type 92.6% and evening type 7.4% of sleep circadian rhythm in obese group. There were statistically significant results on sleep quality with covariance sex and stress, sleep duration, habitual sleep efficiency and sleep disturbance between normal-weight and obese group. There were statistically significant results on sleep quality, sleep duration, habitual sleep efficiency and sleep disturbance in middle type of sleep circadian rhythm between normal-weight and obese group. Conclusion: Therefore, it is necessary to consider subject's sleep pattern to develop education and nursing intervention programs for the obese.

• Journal of Life Science
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• v.22 no.5
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• pp.613-620
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• 2012

To evaluate the effects of sleep habits on the powers of beta waves and the sensory motor rhythm of the electroencephalogram (EEG), female college student subjects were divided into four groups, according to their sleep habits, as follows: GSHG (Good Sleep Habit Group), CSHG (Common Sleep Habit Group: late bedtime), CSDG (Cognitive Sleep Disorder-Delayed Sleep Phase Syndrome Group), and NSDG (Non-cognitive Sleep Disorder-Delayed Sleep Phase Syndrome Group). Brain function was stimulated by reading a book for 3 min in the morning (9~12 am) and the EEG was measured. According to the results, the powers of the beta waves and sensory motor rhythm were not different during the resting period among the four groups. However, during the reading stimulation period, the powers of beta waves and the sensory motor rhythm in the GSHG were significantly greater than in the other groups ($p$ <0.05). Beta powers during stimulation also increased in all brain areas in the GSHG ($p$ <0.05). Interestingly, these were decreased in the frontal and temporal lobes in the CSHG by the reading stimulation ($p$ <0.05). On the other hand, sensory motor rhythm, which represents focusing efficacy, only improved in the GSHG. These results indicate that the brain's focusing function during the reading stimulation was not properly operating in the morning in the female college students who had a delayed bedtime and bad sleep habits.

• International Journal of Internet, Broadcasting and Communication
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• v.11 no.4
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• pp.71-75
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• 2019

Sleep apnea is a disease that causes various complications, and the polysomnography is expensive and difficult to measure. The purpose of this study is to develop an unrestricted wearable monitoring system so that patients can be examined in a familiar environment. We used a method to detect sleep apnea events and to determine sleep satisfaction by non-constrained method using SpO2 measurement sensor and 3-axis acceleration sensor. Heart rate and SpO2 were measured at the finger using max30100. After acquiring the SpO2 data of the user in real time, the apnea measurement algorithm was used to transmit the number of apnea events of the user to the mobile phone using Bluetooth (HC-06) on the wrist. Using the three-axis acceleration sensor (mpu6050) attached to the upper body, the number of times of tossing and turning during sleep was measured. Based on this data, this algorithm evaluates the patient's tossing and turning during sleep and transmits the data to the mobile phone via Bluetooth. The power source used 9 volts battery to operate Arduino UNO and sensors for portability and stability, and the data received from each sensor can be used to check the various degree between sleep apnea and sleep tossing and turning on the mobile phone. Through thisstudy, we have developed a wearable sleep apnea measurement system that can be easily used at home for the problem of low sleep efficiency of sleep apnea patients.

• Fashion & Textile Research Journal
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• v.5 no.1
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• pp.77-81
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• 2003

The purpose of this study was to investigate the effect of multi-functional fabric on EEG and growth hormone (GH) during sleep and quality of sleep with the 9 young female athletes. The subjects participated in separated experimental procedure; sleeping in multi-functional fabric wear (experimental group) and cotton wear (control group) for 450min. During the night (22:00-05:30), we recorded the changes of nocturnal polysomnographic sleep recording and GH were measured every 60min. The results show that there are significant differences in percentage of stage 1, 2 and slow wave sleep (SWS) between two groups(S1, p<.05; S2, SWS, p<.01). The SWS percentage of experimental group is 1.89 times higher than control group. The changes of GH secretion varied depending on two experimental procedures. The peak of GH secretion in experimental group is more than controls by 2.4time (p<.001). The quality of sleep in experimetal group is significantly higher than control (p<.01). These results suggest muti-functional fabric wear is effective in inducing the deep sleep and increasing GH and quality of sleep.

• Journal of Korean Biological Nursing Science
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• v.20 no.1
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• pp.30-37
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• 2018

Purpose: The purpose of this study was to examine the relationship between sleep quality and stress among nursing students. Methods: A cross-sectional study was conducted with 94 nursing students from a University in Seoul. Participants completed questionnaires and the data were analyzed using t-test, ANOVA, and Pearson correlation coefficients. Results: The mean score of sleep quality was $6.93{\pm}2.66$ among nursing students and 81.9% had a sleep problem. The mean score of stress was $18.61{\pm}4.84$. Sleep quality was significantly different by clinical practice days per week, subjective physical health status, and subjective mental health status. Stress levels were significantly different by subjective physical health status, subjective mental health status, social relationship satisfaction, and satisfaction levels of nursing major and university. A significant relationship between sleep quality and stress (r= .45, p< .001) was found, meaning that a lower quality of sleep was significantly correlated with higher stress level. Conclusion: The results indicated that most nursing students had sleep problems and stress. Therefore, interventions are needed to be developed to lower the level of stress and increase the quality of sleep among nursing students.

• Journal of Korean Biological Nursing Science
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• v.19 no.3
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• pp.198-205
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• 2017

Purpose: The purpose of this study was to identify sleep patterns, alertness, and fatigue of shift nurses according to circadian types. Methods: The researchers' enrolled 17 nurses doing shift work in a tertiary hospital. To evaluate circadian types, a morningness-eveningness questionnaire (MEQ) was administered. Sleep patterns were examined using an actigraph for 14 days. To assess alertness and fatigue, Visual Analogue Scale (VAS) was used. The data were analyzed using ANOVA and Kruskal-Wallis test with a SPSS 21.0 program. Results: The researchers found that 17.6% of participants reported morning type, 47.1% neither type, and 35.3% evening type. Mean total sleep time (TST) was 6.8 h, mean sleep efficacy was 82%, level of alertness was 6.54, and level of fatigue was 5.49, regardless of the type of shift work. Evening type nurses had higher variation in TST and alertness, according to the shift patterns than other circadian type nurses. Evening type nurses also had higher fatigue levels than other circadian type nurses. Conclusion: Sleep, alertness, and fatigue were related with circadian types. These results suggest that circadian rhythm management in shift work nurses, particularly in evening type nurses is urgently needed to improve sleep patterns, alertness, and to decrease the level of fatigue.

• Journal of the Korean Operations Research and Management Science Society
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• v.32 no.4
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• pp.89-99
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• 2007

In this paper, an analytic model of a sleep mode operation in the IEEE 802.16e is investigated. A mobile subscriber station(MSS) goes to sleep mode after negotiations with the base station(BS) and wakes up periodically for a short interval to check whether there is downlink traffic to it. If the arrival of traffic is notified, an MSS returns to wake mode. Otherwise, it again enters increased sleep interval which is double as the previous one. In order to consider the situation more practically, we propose the sleep mode starting threshold, during which MSS should await packets before it enters the sleep mode. By modifying the M/G/l with multiple vacations model, energy consumption ratio(ECR) and average packet response time are calculated. Our analytic model provides potential guidance in determining the optimal parameters values such as sleep mode starting threshold, minimal sleep and maximal sleep window.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.21 no.4
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• pp.403-412
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• 2014

Purpose: Shift work disrupts the synchronization between the human biological clock and the environment. Sleep disturbances are common for shift work nurses, and may threaten patient safety. This study was done to investigate the sleep characteristics and medication errors (ME) of intensive care unit (ICU) nurses who work shifts, and ascertain if there is an association between these factors. Methods: Data were collected using a self-report questionnaire from 126 ICU nurses on three shifts. Collected data included their sleep characteristics including sleep patterns and sleep disturbances, and ME for the past 2 weeks. Results: There were significant differences in sleep duration and sleep latency according to shift. Day shift nurses had the shortest sleep duration, and their sleep latency was the longest (about 49 minutes) compared to nurses on evening and night shifts; 54% reported sleep disturbances, 16% experienced ME, and among these nurses 50% were on the night shift. Logistic regression analysis revealed significant associations between nurses' sleep duration and ME (adjusted OR 0.52 [95% CI 0.32-0.85]). Conclusions: The results confirmed that shift work nurses in the ICUs experience sleep disturbance, and that less sleep is associated with ME.