• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.4B
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• pp.329-337
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• 2009

In wireless networks, maximizing throughput and minimizing energy consumption are two conflicting objectives. For elastic traffic, it is important to enhance the throughput since it directly affects the quality-of-service(QoS) of users. At the same time, the energy consumption should be minimized in order to prolong the battery lifetime of the mobile station. In this paper, we propose an energy efficient sleep scheme that considers throughput and energy saving simultaneously. The proposed scheme is designed for an efficient tradeoff between throughput and energy saving when receiving elastic traffic. Through extensive simulations, we compare the proposed scheme with the conventional scheme. Our proposed scheme outperforms the conventional one in terms of utility, i.e., user satisfaction, which is defined as inversely proportional to the weighted multiplication of service completion time and energy consumption.

• Mood & Emotion
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• v.12 no.2
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• pp.128-136
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• 2014

Objectives : This study was undertaken to investigate the prevalence of depressive symptoms and their related factors among a group of medical students. Method : A total of 874 (529 male and 345 female) medical students were randomly selected to participate in a survey. Depressive symptoms, satisfaction with life, health behavior including alcohol use, stress, sleep disturbance and happiness were collected using self-reported questionnaires. Results : The prevalence of depressive symptoms was 10.8%. In stepwise multiple regression analysis, lower satisfaction of life, daytime dysfunction due to sleepiness, history of suicidal attempt, stress, sleep disturbance were found to be significant relating factors of depressive symptoms. In moderated regression analysis, the result showed that the impact of life stress were moderated by satisfaction of life on depressive symptoms, but the moderating effect of happiness was not significant. Conclusion : This study showed considerably high prevalence of depressive symptoms and BDI score in medical students. The findings suggest that early detection of depressive symptoms and intensive mental health promotion program is needed in order to improve medical student's mental health status.

• Child Health Nursing Research
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• v.22 no.4
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• pp.363-369
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• 2016

Purpose: Fatigue in mothers of hospitalized children is an important component for her child's health. This study was done to identify factors influencing fatigue in mothers of hospitalized children. Methods: A descriptive correlation study design was used. Participants were 157 mothers of hospitalized children in a university hospital located in one city. Data were analyzed using t-test, ANOVA, Pearson correlation coefficients and stepwise multiple regression. Results: Mean score for fatigue in mothers of hospitalized children was $2.11{\pm}0.53$. There were significant differences in scores for fatigue in these mothers according to education, sleep satisfaction, and family support. Multiple regression analysis showed that the important factors related to fatigue in mothers of hospitalized children were parenting stress (${\beta}=.44$), hours of sleep (${\beta}=-.25$), and age (${\beta}=-.21$). These factors explained 38% of the total variance. Conclusion: Research results suggest that nursing interventions for mothers of hospitalized children are needed in order to improve the comfort and health of the mothers and facilitate the recovery of their child.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.01a
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• pp.65-67
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• 2012

수면은 인간에게 삼분의 일 정도 잠을 자면서 보낸만큼 매우 중요한 생리 현상이다. 본 논문에서는 이러한 수면을 환경을 측정하고 수면의 질 발전 방향을 모색한다. 수면 측정을 위하여 $X^2$ 히스토그램을 이용한 장면 전환 검출 방법을 이용한다. $X^2$ 히스토그램 방법은 통계학적 장면 전환 검출 방법의 하나로서 다른 히스토그램 방법보다 성능이 우수하기 때문에 많은 연구에서 사용된다. 또한 수면의 질 발전을 위하여 피로도, 음주도, 그리고 공복도를 입력하여 각각의 상황에 따른 뒤척임을 추출한다.

• The Journal of the Korea Contents Association
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• v.18 no.9
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• pp.441-453
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• 2018

The purpose of this study is to develop a meditation application to promote home practice in a meditation-based intervention program and test its effects. In most cases, meditation-based intervention programs put an emphasis on home practice, which means it is an important matter to increase motivation for home practice and encourage people to do home practice more. The investigator administered an eight-week Korean Mindfulness-based Stress Reduction (K-MBSR) program to college students participating in a liberal arts course at A University. While the experiment group (N = 22) received a meditation application, the comparison group (N = 19) received no meditation application. The amount of home practice was measured based on the practice logs kept by the participants. The difference in psychological effects between the groups was checked by measuring mindfulness, subfactors (noticing and return to body) of body awareness, life satisfaction, acceptance action, and sleep quality before and after the experiment. The findings show that the experiment group recorded significantly greater amounts of home practice than the comparison group. As for the effects of meditation, the experiment group recorded higher points in mindfulness, body awareness, life satisfaction, acceptance action, and sleep quality than the comparison group. These findings demonstrate that a meditation application can be useful as a means of assistance to promote the effects of a meditation-based intervention program. The study also discussed proposals for a follow-up study.

• Journal of the Korean housing association
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• v.17 no.1
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• pp.97-105
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• 2006

The purposes of this study are to find out the current status and features of earth housing, and to explore users' level of satisfaction and needs of improvement about earth housing. Primary findings are as follows: (1) The area of earth housing is generally 25-34 pyong and the construction cost of earth housing is usually 3,000,000-3,400,000 won per pyong. (2) The age of earth house users is generally forties, fifties, and sixties. And their occupation is usually retiree and farmer. The age of earth based pension users is generally twenties and thirties. (3) The construction method of earth housing is usually earth brick structure reinforced with wood structure and earth brick structure(adobe). (4) The finish of outer wall is generally earth brick laying and earth plaster. And the finish of inner wall is usually wall paper and earth plaster. Roof tile and asphalt shingle is frequently observed as roof finish. (5) Users' satisfaction about earth housing is investigated high level. Especially, the satisfaction degrees about faculty of humidity control, stink elimination, prevention from sick house syndrome, support for psychological stabilization and deep sleep are observed very highly. (6) Reduction of construction cost and prevention of crack is investigated as needs of improvement about earth housing.

• Journal of Oral Medicine and Pain
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• v.23 no.4
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• pp.419-432
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• 1998

The purpose of this Study was to examine the efficacy and compliance of a mandibular advancement device(MAD) according to the severity of sleep apnea in the snorers and obstructive sleep apnea patients. Fifty-four patients (45 males, 9 females, aged 20 - 68years ) who visited Seoul National Uiversity Dental Hospital(SNUDH) to seek for the treatment of snoring and sleep apnea were classified into four groups according to the results of the nocturnal polysomnography and they were instructed to wear MAD regularly which was designed to increase the size of the upper airway by advancing the mandible. The evaluation of the efficacy and compliance of the MAD according to the severity of apnea and the duration after the usage of MAD ( 1week, 1month, 3months, 6months, 12months) was made by using quesionnaires mad in Department of Oral Medicine and Oral diagnosis, SNUDH. The obtained results were as follows : 1. All subjects results were habitual snoreres and 43 patients(79.6%) complained the loudness of snoring that can be heard out of the room. 2. Apnea index(AI) of the total subjects was mean 29.4$\pm$26.9 and respiratory disturbance index(RDI)was mean 37.6$\pm$28.0. And there was nodifference in the efficacy and the compliances of MAD according to the severity of apnea. 3. The severityi of apnea by the questionnaires significantly corresponded with the results of nocturnal polysomnography, and this fact potentiated the diagnostic value of the questionnaire. 4. after the usage of MAD, there was significant improvement in the frequency of snoring, the loudness of snoring, frequency of apnea, daytime sleepiness nad the refreshment after sleep(p<0.001) regardless of the apnea index(AI) and respiratory distrubance index(RDI). 5. The degree of the satisfaction with MAD was mean 74.4$\pm$18.4% and that of the discomfort with the MAD was 31.4$\pm$19.6%. But there was no serious complication in occlusion and temporomandibular joint with the usage of MAD and the duration of the discomfort was mean 3.3$\pm$2.2 weeks. 6. Forty-one patients(75.9%) continued the usage of MAD but thirteen patients(24.1%) stopped the use of MAD because of the discomforts and insufficient results with it.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1203-1211
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• 2012

The purpose of this study was to compare the health status, sleep and depression and to examine relationships between health status, sleep and depression by employment status in the elderly. This study used the data from the "2008 Korean National Survey on Older Adults" by Ministry of Health, Welfare and Family. Out of the total 15,146 Korean elderly surveyed, 5,204 subjects with job and 9,942 subjects without job at the present were used in a final analysis. There were significant differences in health status, sleep and depression by employment status. As for old adults with job, job satisfaction had the greatest effect on depression, followed by perceived health status, difficulty of daily activities by disease, and deep-sleeping days in the order. These variables accounted for 29% of depression. As for old adults without job, perceived health status had the greatest effect on depression, followed by difficulty of daily activities by disease, deep-sleeping days and total sleeping time in the order. These variables accounted for 32% of depression. Therefore, the health-promotion intervention to improve the health status, sleep and depression of the elderly should be planed and provided considering such differences by employment status.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.2
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• pp.73-76
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• 2013

Uvulopalatopharyngoplasty (UPPP) is one possibility for the treatment of Obstructive Sleep Apnea (OSA). The aim of this study was study the analysis of polysomnography of pre-UPPP and post-UPPP. All patients were evaluated by means of a physical examination, the epworth sleepiness scale (ESS), the beck depression inventory (BDI) and the nocturnal polysomnography (PSG) before surgery, and 6~12 months after surgery. A total of 15 patients were investigated. All underwent UPPP. The patients were between 26 and 62 years old ($mean{\pm}SD$; $39.7{\pm}10.9$) with a lean body mass index (BMI) of $mean{\pm}SD$; $26.2{\pm}3.0kg/m^2$. The comparison of sleep questionnaires showed that after UPPP, the patients had a significantly lower BMI ($26.2{\pm}3.0kg/m^2$ vs $26.0{\pm}3.4kg/m^2$, p=0.241), ESS ($10.0{\pm}5.4$ vs $6.9{\pm}3.2$, p=0.022), BDI ($9.2{\pm}8.2$ vs $4.2{\pm}4.3$, p=0.343) and higher blood pressure ($127.5{\pm}12.1$ vs $123.7{\pm}12.0$, p=0.272) compared to before UPPP. The comparison of sleep parameters showed that after UPPP, patients had a significantly lower stage N1 ($108.8{\pm}53.1$ vs $82.2{\pm}48.9$, p=0.016), lower sleep latency ($4.9{\pm}4.4$ vs $2.0{\pm}1.7$, p=0.083), a lower total arousal number ($210.6{\pm}90.3$ vs $147.1{\pm}87.3$, p=0.019), lower oxygen desaturation index (ODI) ($30.2{\pm}20.9$ vs $10.2{\pm}15.1$, p=0.006), lower apnea-hypopnea index (AHI) ($31.6{\pm}22.4$ vs $10.9{\pm}15.4$, p=0.005), and a lower respiratory disturbance index (RDI) ($37.4{\pm}21.3$ vs $18.5{\pm}16.5$, p=0.008) compared to after UPPP. The comparison of sleep parameters showed that after UPPP, patients had a significantly higher stage N2 ($154.0{\pm}39.9$ vs $180.5{\pm}49.5$, p=0.017), higher REM ($58.5{\pm}29.7$ vs $72.6{\pm}34.0$, p=0.249), higher $meanSaO_2$ ($94.3{\pm}2.0$ vs $95.9{\pm}0.9$, p=0.043), and higher $meanSaO_2$ ($79.3{\pm}8.5$ vs $83.1{\pm}7.9$, p=0.116) than before UPPP. After UPPP, 6 patients were cured, 2 showed marked improvement, and 7 did not improve. After surgery, the success of the treatment was at 53%. The subjective patient satisfaction was higher than before the surgery.

• Journal of the Korean society of biological therapies in psychiatry
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• v.24 no.3
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• pp.230-238
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• 2018

Objectives : Among adolescents, the proportion of daily smoking tends to increase with age, and does not return to the previous level. Therefore, we examined the factors associated with smoking frequency in a nationwide sample of Korean adolescents to help prevent the progression of smoking. Methods : Among 127,804 adolescents who participated in the 2016 and 2017 Korean Youth Risk Behavior Web-Based Survey, data from 7,781 adolescents who replied that they currently smoked were analyzed. According to the frequency of cigarette smoking, participants were classified into daily and non-daily smokers. Participants' socio-demographic characteristics, smoking behavior, and psychological problems including perceived stress, depressive mood, and suicidality were assessed. Results : There were 3,627(47.4%) daily smokers and 4,154(52.6%) non-daily smokers. Low parental educational level, and early smoking experience were positively associated with daily smoking. High academic achievement, and high socio-economic status were negatively associated with daily smoking. Daily smoking was positively associated with lower happiness, lower sleep satisfaction, and severe stress during the past 12 months. Factors affecting suicide attempts of smokers were sex, residential type, socioeconomic status, and early smoking experience. Conclusion : The results indicated that socially disadvantaged families, and smoking experience with young age influenced daily smoking among Korean adolescents. Daily smoking was associated with psychological problems including lower happiness, lower sleep satisfaction, and severe stress. Early smoking experience influenced suicidal attempts among Korean adolescent smokers. Early intervention for smoking cessation in this high-risk group may contribute to prevention of these psychiatric complications of smoking.