• Sleep Medicine and Psychophysiology
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• v.18 no.2
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• pp.72-75
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• 2011

Sleep disorders such as insomnia, obstructive sleep apnea (OSA), and restless legs syndrome (RLS) are very common disorders and may cause significant burden in terms of individual as well as societal aspects. Sleep insufficiency from such sleep disorders may cause deleterious effects on daily work life and may be associated with other major medical or psychiatric disorders including cardiovascular disease, diabetes mellitus, depression, and anxiety disorder. Various motor or occupational accident may result from the sleep problems. In addition, recent researches provide the method to evaluate the lost productivity time in terms of absenteeism and presenteeism. Moreover, several studies on cost-effectiveness of treatment of sleep disorders show that it is cost-effective.

• Journal of Families and Better Life
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• v.32 no.2
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• pp.41-52
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• 2014

The present study investigated the sleep patterns 1-to 3-year-old children and examined whether their sleep patterns would predict their early adjustment to daycare centers. The participants were 239 young children attending daycare centers in Seoul. The data on children's sleep patterns were collected by parent report. Children's adjustment to daycare was assessed by daycare providers' reports. The data were analyzed by means of Chi-square test, t-test, Pearson's correlation, ANOVA and discriminant analysis. The results were as follows: Children from dual-earner families had shorter nocturnal sleep duration than those from single-earner families. There was no significant relation between daytime sleep duration and sleep-onset time at night. It was found that children who go to bed earlier were more likely to get sufficient sleep without nocturnal wakefulness. Age and total sleep duration were seen to be significant variables when it came to discriminating between the adjustment versus maladjustment groups.

• Sleep Medicine and Psychophysiology
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• v.7 no.1
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• pp.51-59
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• 2000

Objectives: It is been reported that sleep patterns change significantly during the adolescent years. In Korea, the sleep patterns of adolescents have not been investigated systematically. The authors performed preliminary study about sleep patterns of middle and high school students in Seoul before nationwide study. Methods: The authors selected one of middle and high schools located in typical middle class area in Seoul. The study was performed during the periods when examination or vacation did not affect the sleep cycle. Fifty to one hundred male and female students were selected from one school year each. One of investigators explained the purposes and methods of this study to the students and gave additional explanation to the teachers in charge. We designed a questionnaire for subjects to describe the nap time, bedtime, sleep latency, total sleep time, rise time and sleep efficiency, and the students recorded sleep logs for seven days including weekend. Eight hundred three students answered the questionnaires. Among them, we selected the subjects who recorded sleep logs at least three days and filled up the questionnaires completely. Finally, seven hundred seventy one subjects were included in this study. Weekend was defined as the time from Saturday morning to Sunday morning, and Sunday sleep patterns were treated separately. Results: Across the six school years, school-night bedtimes were delayed one hundred twenty four minutes and school-ight rise times were advanced by thirty five minutes. School-night total sleep times were decreased by one hundred fifty eight minutes, and weekend bedtimes were delayed by one hundred twenty five minutes. The students tended to oversleep on weekends, and the mean of weekend oversleep was ninety six minutes. But, bedtime in weekends was not delayed. Daytime sleep, sleep latency and sleep efficiency were not changed greatly across six school years. Total sleep time of female students was decreased significantly between third middle school year and first high school year, but time of male students was decreased between first and second high school year. Conclusion: It is supposed that sleep deficiency of middle and high school students in Seoul was due to delayed bedtimes and advanced rise times across the school years.

• Safety and Health at Work
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• v.9 no.2
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• pp.236-238
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• 2018

Sleep deprivation may cause accidents, and it has deteriorating effects on health. A measurement of postural steadiness by a portable and affordable Nintendo Wii Fit balance board can be used to quantify a person's alertness. At work, people are under the influence of their environment-often other peopl-dthat may affect their alertness. This work investigates whether sleep deprivation among people is "contagious," as quantified by sway measures. We measured 21 volunteers' postural steadiness while alert and sleep deprived. During the measurements, a screen placed in front of the participants showed a footage of either alert or sleep-deprived faces. We found a significant difference between the day time and night time steadiness, but found no effect resulting from watching footage of sleep-deprived people. This finding shows that a posturographic sleepiness tester quantifies physiological sleep deprivation, and is insensitive to the influence of social factors.

• Korean Journal of Adult Nursing
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• v.28 no.1
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• pp.13-29
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• 2016

Purpose: This study was performed to evaluate the effects of non-pharmacological interventions on sleep disturbance amongst adults aged 55 and above. Methods: PubMed, Cochrane Library, EMBASE, CINAHL and several Korean databases were searched. The main search strategy combined terms including non-pharmacological interventions and presence of insomnia. Non-pharmacological interventions included cognitive behavioral therapy, auricular acupuncture, aromatherapy, and emotional freedom techniques. Methodological quality was assessed using Cochrane's Risk of Bias for randomized studies and Risk of Bias Assessment tool for non randomized studies. Data were analyzed by the RevMan 5.3 program of Cochrane Library. Results: Sixteen clinical trials met the inclusion criteria with a total of 962 participants. Non-pharmacological interventions was conducted for a mean of 5.5 weeks, 7.7 sessions, and an average of 70 minutes per session. The effects of non-pharmacological interventions on sleep quality (ES=-1.18), sleep efficiency (ES=-1.14), sleep onset latency (ES=-0.88), awakening time after sleep onset (ES=-0.87), and sleep belief (ES=-0.71) were significant, and their effect sizes were ranged from moderate to large. However, the effects on total sleep time and insomnia severity were not significant. Conclusion: The findings of the current study suggest that non-pharmacological interventions have a positive impact on attitudes and beliefs about sleep, sleep quality, sleep duration, and sleep efficiency. Therefore, the findings of the study provide an evidence to incorporate various non-pharmacological interventions into nursing practice to improve both sleep quality and quantity in patients with insomnia.

• Journal of Internet Computing and Services
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• v.8 no.2
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• pp.43-54
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• 2007

The effective power consumption is the primary issue in a sensor network which consists of the sensor nodes with limited battery power. So, most of the MAC protocols in sensor networks have been designed with the consideration of energy efficiency. Generally, these protocols make use of the listen and sleep mode periodically. However, this approach inevitably causes a long transmission delay on the data forwarding path, which is mainly resulted from the sleep time of the receiver node. This paper deals with a design of DT-MAC(Data Transmission centric MAC) protocol, with minimizes the data transmission delay while it forces each node to consume its energy efficiently. Thus, a node received a packet converts its remained sleep time to the pseudo_listen time, in which the node is able to transmit a packet. With benefit of the pseudo_listen period, the data transmission delay along with the data forwarding path will be shortened as much as it possible. Therefore, DT-MAC protocol is very suitable to the various applications which require a real time sensing data such as disaster and fire alarm.

• Sleep Medicine and Psychophysiology
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• v.13 no.2
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• pp.67-74
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• 2006

Introduction: Excessive daytime sleepiness and cataplexy are key features of narcolepsy. Modafinil is psychostimulant used in the treatment of narcolepsy. In this study, we evaluated effects of modafinil on nocturnal sleep structure and sleep latency in multiple sleep latency test and clinical features. Methods: Twelve narcoleptic patients (7 male, age: $22.9{\pm}2.6\;yrs$) were participated in the study. All of them had done nocturnal polysomnography (nPSG), multiple sleep latency test (MSLT), clinical symptoms scales and have repeated same procedure after taking 200 mg of modafinil. We have done linear mixed model analysis to describe effects of group, medication and nap time on these measures. Results: Modafinil did not affect clinical scales except PSQI which had been reduced after medication. In this study, Modafinil reduced total sleep time, sleep efficiency and increased wake after sleep onset and percent of arousal during sleep in nocturnal polysomnography and prolonged mean sleep latency in multiple sleep latency tests in both group. Discussion: Modafinil has stimulant effect of central nervous system but its effect on night sleep is less than other psychostimulants such as methylphenidate. We ascertained that modafinil affected total sleep time, sleep efficiency and percent of wake during sleep but did not effect on sleep structure. Modafinil was effective in the management of day time sleepiness. Modafinil can enhance alertness of control group without day time sleepiness.

• The Journal of the Korea Contents Association
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• v.10 no.2
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• pp.35-42
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• 2010

The increasing regular medical check up rate for early diagnosis in disease has increasing sleep endoscopy rate because of reduction with discomfort. The purpose of this study was to determine the number of recovery bed as increasing sleep endoscopy rate using check up time, waiting time & recovery time at a general hospital in Seoul. This study was analyzed using ARENA 10.0 program. At present and as increasing of sleep endoscopy rate 10%, 20% was increased recovery time, waiting time & the rate of bed inflection. So at present, the number of recovery bed has to increase for client's safety and as increasing of sleep endoscopy rate 10%, 20% has to increase 3 and then waiting time decreased in 2 minutes.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.686-693
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• 2009

In this paper, we propose an efficient tag sleep method utilizing empty time slots for improving the tag collection performance in active RFID systems. In the proposed tag sleep method, the reader detects the occurrence of empty time slots by carrier sensing and utilizes the wasted empty time slots to transmit sleep commands to the collected tags throughout the framed slotted aloha-based tag collection process, resulting in reducing the time required for tag collection. Via the simulation experiments, we evaluated the performance of the tag collection applied with the proposed tag sleep method, compared with that of the basic tag collection. The simulation results showed that the tag collection applied with the proposed tag sleep method could reduce the average tag collection time by 12.28%, 12.30%, and 13.31 %, for the framed slotted aloha with the fixed 128 time slots and 256 time slots, and the dynamic framed slotted aloha anticollision protocols, respectively.

• Sleep Medicine and Psychophysiology
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• v.15 no.2
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• pp.82-86
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• 2008

Objectives: Obstructive sleep apnea syndrome (OSAS) not only causes respiratory disturbances during sleep but also decreases the quality of nocturnal sleep through sleep fragmentation and sleep structure change. We aimed at comparing the changes in sleep fragmentation and structure between baseline (diagnostic) nocturnal polysomnography (NPSG) and nCPAP (nasal continuous positive airway pressure) titration trial. Methods: One hundred and three patients with a baseline night of respiratory disturbance index (RDI) of 5 or greater and reduced RDI score during nCPAP titration night were retrospectively selected for the study. Sleep fragementation and sleep structure between baseline NPSG and the NPSG during nCPAP titration were compared. Sleep fragmentation index (SFI) was defined as the total number of awakenings and shifts to stage 1 sleep divided by the total sleep time in hour. SFI and other polysomnographic parameters were statistically compared between the two nights. Results: SFI during baseline NPSG and nCPAP titration nights were $29.0{\pm}13.8$ and $15.2{\pm}8.8$, respectively, indicating a significant SFI decrease during nCPAP titration (t=9.7, p<0.01). SFI showed significant negative correlations with sleep efficiency (r=-0.60, p<0.01) and total sleep time (r=-0.45, p<0.01) and a positive correlation with RDI (r=0.28, p<0.01). Conclusion: Use of nCPAP, even during the titration, significantly decreases sleep fragmentation and improves sleep structure in OSAS patients. We suggest that SFI may be utilized as a measure of assessing OSAS severity and nCPAP efficacy.