• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.1
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• pp.1-6
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• 2006

This study was performed to evaluate sleep efficiencies and conditions for comfortable sleep based on the analysis of EEGs and MST under four thermals conditions. 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 of $4.1\times4.9\times2.7m$ size. EEGs were obtained from C3-A2 and C4-Al electrode sites. Sleep stages were classified, then TST, SWS latency and SWS/TST were calculated for the evaluation for sleep efficiencies on thermal conditions. As results, it was concluded that indoor thermal environments of $24\~26^{\circ}C$ was the best for comfortable and deep sleep.

• Sleep Medicine and Psychophysiology
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• v.14 no.2
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• pp.86-91
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• 2007

Background: Actigraphy is a reliable and valid method for assessing sleep in normal, healthy populations, but it may be less reliable and valid for detecting disturbed sleep in patients. In this study, we attempted to assess the utility of actigraphy in the estimation of sleep quality in patients with obstructive sleep apnea syndrome (OSAS), a major sleep disorder. Method: We analyzed the data of patients who underwent polysomnography (PSG) and actigraphy simultaneously for one night at the Center for Sleep and Chronobiology, Seoul National University Hospital from November 2004 to March 2006. Eighty-nine subjects with OSAS alone and 21 subjects with OSAS and periodic limb movement disorder (PLMD) were included for final data analyses between groups. Polysomnographic and actigraphic data were also compared. Results: In subjects with mild OSAS (RDI<15), modretae ($15{\leq}RDI$<30), and OSAS with PLMD, PSG and actigraphy did not show significant difference in total sleep time and sleep efficiency. However in severe ($30{\leq}RDI$) OSAS subjects, PSG and actigraphy showed significant difference in total sleep time and sleep efficiency. In all patients, no correlations were found between sleep parameters from PSG and from those using actigraphy. Conclusions: We suggest that in severe OSAS patients, PSG is the diagnostic tool. In mild and moderate cases, actigraphy might be used as a screening tool.

• 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.

• Sleep Medicine and Psychophysiology
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• v.14 no.1
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• pp.20-25
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• 2007

The present study compared the actigraphic indices between both wrist actigraphies (WATGs), and the sleep estimates between each WATG and nocturnal polysomnography (NPSG) to assess their differences and consistencies. We studied 22 right-handed subjects (mean age $43.9{\pm}13.3\;years$, M：F=14：8) with untreated primary sleep disorders (primary insomnia=8, simple snorer=2, obstructive sleep apnea=12) undergone by overnight both WATGs and NPSG, simultaneously. Comparison and correlation were analyzed between right and left wrist actigraphic data. In the sleep estimates of both WATGs and NPSG, each WATG was compared and correlated with NPSG in sleep period time (SPT), total sleep time (TST), sleep latency (SL), sleep efficiency (SE) and wake time (WT). Sleep indices between both WATGs showed significant positive correlations with no correlations in SL and fragmentation index (FI). There were no differences in sleep indices between both WATGs. SPTs of both WATGs, SL of left WATG, and TST of right WATG showed positively significant correlations, and SE of right WATG did negatively significant correlation in sleep indices between each WATG and NPSG. As each WATG was compared to PSG, SPTs of both WATGs and WT of right WATG were decreased, and TST and SE of right WATG and SL of left WATG were increased. Inconsistent SL and FI between both WATGs indicate that the activities between both WATGs can differentially happen during wake or arousal. Inconsistent sleep estimates between each WATG and NPSG may indicate the limited usefulness in measuring and analyzing one-night sleep by using WATG.

• Proceedings of the ESK Conference
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• 1998.04a
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• pp.131-136
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• 1998

2개의 simulated된 잠수 실험 즉, 심도 19 ATA와 24 ATA의 고압 Heliox 환경하에서, 4명의 다이 버를 대상으로 하여연 188일간 매일 23:00부터 익일7:00시 사이에 각 다이버에대해서 표준적인 polysomnography를 기록했다. 2개의 잠수조건 하에서 양 실험 모두 해저에서 체재하는 동안 의 밤과 감압하는 동안의 밤 동안에는 총수면시간 (Total Sleep Time)의 단축, 수면효율(Sleep Efficiency)의 감소, 입면잠시(Sleep Latency)의 연장, 중도각성회수 (Number of Awakeningss) 와 감소를 보였지만, 어느쪽도 뚜려한 변화가 있었다라고는 할 수 없었다. 24 ATA 잠수조건에서 의 해저에서 체재하는 동안의 밤과 감압하는 동안의 밤 동안에서는 19 ATA 잠수조건에 비해서 4 단계수면(stage 4 sleep )만 유의한 감소를 보였다. 2개의잠수조건 모두 잠수기간 중에 있어서 는 각성하기 쉬운 상황이었으며, 기본적인 수면패턴에 있어서는 큰 변화는 보이지 않았다.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.7
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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.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.12
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• pp.652-662
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• 2019

This study demonstrates the association between total sleep duration of adolescents, and its effects on their physical and mental health. Chi-square test and the multiple logistic regression model were applied to analyze the data collected in 2018 by the Korean Youth Health Behavior Survey (n = 52,928), conducted by the Korea Centers for Disease Control & Prevention. Our analysis indicates increased suicidal ideation with insufficient total sleep duration as per the recommended amount and grade (OR: 1.17, 95% CI: 1.06-1.29, p-value: 0.00]. Especially, insufficient sleep among adolescent girls significantly increases the risk of suicidal thoughts (OR: 1.22, 95% CI: 1.06-1.41, p-value: 0.01). Sufficient sleep showed reduced risk of suicidal ideation among boys (OR: 0.83, 95% CI: 0.71-0.96, p-value: 0.02). We propose that to reduce the risk of suicide among teenagers, policy considerations are required to ensure sufficient sleep.

• Sleep Medicine and Psychophysiology
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• v.5 no.1
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• pp.111-117
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• 1998

Objectives : 'First-night effect' has been a well-known concept since 1960's. It is important because it is one of the major factors to be considered in assessing the reliability of polysomnographic data. However, 'reverse first-night effect' has also been described, resulting in the inconsistency of conceptualization. We attempted to investigate on the first-night effect in adults by having each of them take two nights of polysomnography in a controlled environment. Young healthy adult volunteers were chosen as subjects in order to rule out age- or health-related confounders. Methods : Polysomnography was performed on eight male medical students (mean $age=23.5\;{\pm}\;0.9$) for two nights with Grass model 78 polysomnograph. We scored manually under the standard protocol each epoch of the sleep records. Sleep variables were obtained and compared between the two nights. Results : Sleep period time(SPT) and total sleep time(TST) of the third fraction of night were significantly longer on the first night than on the second night (p<0.05). However, other sleep variables such as percentage of each sleep stage, sleep latency, REM sleep latency, number of waking, and sleep efficiency were not different between the two nights. Conclusion : We could not confirm the existence of first-night effect in this study. In healthy young male adults, it may not happen at all or may happen to a very negligible degree. Young healthy adults may have more adaptability to a new sleep environment. Also, the provision of a reasonably comfortable sleep environment could have helped them with abolition of first-night effect.

• Journal of Preventive Medicine and Public Health
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• v.22 no.1 s.25
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• pp.14-24
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• 1989

현재 중국에는 55개의 소수민족이 있으며, 그 인구총수는 6,700만을 초과한다. 중국정부는 특히 70년대 후반서부터 소수민족에 대한 일연의 보호정책을 쓰고 있으며 다수민족인 한족에 대하여 엄격히 실시하는 1가구 1자녀 정책에서도 소수민족을 제외하고 있다. 이에 따라 소수민족의 증가는 현저하게 늘었다. 그러나 전반적인 인구학적특성으로 보면 소수민족은 아직 후진성을 면하지 못하고 있다. 조선족이라고 일컫는 재중 우리교포는 한족을 포함하여 중국내 어느 민족과 비교하여도 인구학적으로 독특한 위치를 차지하는 경우가 많다. 예를 들어 인구증가율은 가장 낮으며 어느민족보다 앞서서 1970년대 중반에 이미 대치수준 이하의 출생률에 도달한 것으로 믿어지고 있다(Han 등, 1988). 문맹률은 최하이며 대학수업율은 최고로 높다(장(張), 1984). 사망률은 전소수민족중 가장 낮고 평균 수명은 가장 길다(Dowdle, 1984). 이렇게 재중 조선족은 인구학적으로 가장 선진적이기 때문에 1자녀 정책에 대한 수용 준비가 다른 민족보다 앞서 있다고 할 수 있겠다. 물론 조선족은 소수민족에 속하기 때문에 1자녀정책에 구애될 필요가 전혀 없다. 따라서 조선족 가정에서 1자녀만을 낳겠다는 서약을 하여 이른바 '독생자녀증'을 영수하면 이것은 한족의 경우와 달리 자율의사에 따른 것이라 할 수 있을 것이다. 이 논문에서는 다음 두가지를 다루기로 하겠다. 즉, 조선족이 인구학적으로 보아 딴 민족에 비하여 어떤 위치에 있으며, 또 중국의 중요인구정책인 1가정 1자녀제에 어떻게 반응하고 독생자녀증을 어떻게 수용하느냐 하는 것이다. 이 밖에 중국의 대소수민족 인구정책의 앞날에 대하여도 약간의 전망을 하여볼까 한다.스와 여기에 사용되는 신호 방식을 논의하고 있다. 그 외에도 전광 통신망 운용에 필요한 라우팅 및 파장할당 방법과 OXC를 이용한 그물형 망에서의 보호 및 복구에 대한 연구도 활발히 진행되고 있다.rotene 보충군에 비하여 유의적으로 높았으며 retinyl acetat와 B-carotene 보충군 사이에는 유의적인 차이가 없었다.3.17%로 가장 양호하였으나, 양파망과 염화비닐판을 수직으로 놓은 것은 각각 1.52%와 1.61%로 비교적 저조하였다. 수정 후 40일째부터 90일째까지 측정한 부착치패의 경과 일수에 따른 각장의 성장은 $SL=184.44e^{0.0335X}(r^2=0.9861)$의 회귀직선식으로서 나타났다. 중간육성 시험에서 수심별 성장을 분석한 결과, 비단가리비 치패는 저층보다 표층이 각장 5.92mm, 전중량 6.07g 정도 더 빨리 성장하였다. 시간으로 하여 l 주 44 시간을 기준으로 측정하면 통상질환관리 18.56시간, 지역사회 보건관리 5.67 시간, 모자보건 및 가족계획 5.52 시간, 사업 운영관리 및 지도 4.10시간, 지역사회 조직 및 개발 3.05 시간, 보건정보체계 개발 및 수집 2.94 시간, 사업계획 수립 2.89시간의 순으로 나타났다. 5) 보건진료원의 업무영역별 수행 소요시간의 상판판계를 살펴보면 지역사펴 조직 및 개발을 위 해 소요한 시간은 사엽계획 수립 소요시간 및 보건정 보체계 관리 소요시간과 순상관관계를, 사업 계획 수립 소요시간은 지역사회 보건관리, 모자보건 및 가족계획 관리 소요시간 및 보건정보체제 관리 소요시간과 순상관관계를 나타냈다. 또한 통상질환관리 소요시간은 지역 사회 조직 및 개발, 사업계획 수립, 지역사회 보건관리와 모자보건

• Sleep Medicine and Psychophysiology
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• v.4 no.1
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• pp.66-76
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• 1997

Objectives : The purpose of this study is to analyse sleep habits and sleep disorders in the elderly population ased 65-84 years. Methods : Epidemiological survey was performed at home by means of semi structured interviews in the city of Pusan, Korea. Subjects were randomly selected. The questionnaire consisted of 128 items including demographic findings, sleep habits, sleep disorders, somatic illnesses, and psychological distresses. Results : (1) The mean retiring time was 10.28 h (SD 1.30 h) and the mean wake-up time was 5.24 h (SD 1.33 h). The mean duration of sleep was 5.63 h (SD 1.80 h). The mean sleep onset time was 44.51 min. The mean frequency of daytime napping was 2.49 (SD 3.23). The subjects reported they woke up an average of 2.05 (SD 1.59) times per night. All of the above results were not related to age or gender. However, the mean frequency of difficulty in initiating/maintaining sleep was 2.2 times for men and 3.2 times for women (p<0.05). (2) The prevalence of insomnia was 57.7% and was not related to age or gender. Difficulty in initiating sleep was the most commonly reported insomnia complaint(52.4%). Early morning awakening was reported by 50.0% of patients and difficulty in maintaining sleep was reported by 45.1% of them. Worrying in bed and physical pain were strong contributing factor to insomnia. Conclusions : The results of our study showed several characteristics of sleep habits in the elderly. Sleep disorder in old age is not inevitable or trivial. Since sleep disturbance in older adults is common and distressing, it has implications for general health and well-being. Active concern and therapeutic intervention for the sleep habits and sleep disorders in the elderly are needed.