• Journal of Korea Water Resources Association
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• v.45 no.4
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• pp.349-360
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• 2012

A horizontally curvilinear non-hydrostatic free surface model that was applicable to three-dimensional viscous flows was developed. The proposed model employed a top-layer equation to close kinematic free-surface boundary condition, and an isotropic k-${\varepsilon}$ model to close turbulence viscosity in the Reynolds averaged Navier-Stokes equation. The model solved the governing equations with a fractional step method, which solved intermediate velocities in the advection-diffusion step, and corrects these provisional velocities by accounting for source terms including pressure gradient and gravity acceleration. Numerical applications were implemented to the wind-driven currents in a two-dimensional closed basin, the flow in a steep-sided trench, and the flow in a strongly-curved channel accounting for secondary current by the centrifugal force. Through the numerical simulations, the model showed its capability that were in good agreement with experimental data with respect to free surface elevation, velocity, and turbulence characteristics.

• Journal of the Korea Society of Computer and Information
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• v.25 no.10
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• pp.169-177
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• 2020

The purpose of this study is to identify the effects of stress and sleep quality on depression during clinical practice of nursing students. The subjects of the study were third and fourth graders who experienced clinical practice for more than a semester among nursing students at C University in one region. A total of 107 people were analyzed. Most of the nursing students experienced more than moderate stress and depression during clinical practice, and the quality of sleep was low. During clinical practice, the stress of nursing students showed a weak correlation with the quality of sleep(r=.393, p<.001), and depression showed a strong net correlation with stress(r=.588, p<.001), the quality of sleep(r=.591, p<.001). Factors affecting depression during clinical practice were stress and the quality of sleep. Therefore, effective management methods that can relieve the stress of nursing college students during clinical practice and improve the quality of sleep and active nursing strategies that can prevent depression should be sought.

• Journal of the Korea Convergence Society
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• v.11 no.1
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• pp.33-39
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• 2020

Specialists have developed pillows that take into account sleep science and ergonomics, such as comfort for lying on your side. This pillow is made of natural latex material, and improved resilience after a certain period of time. A new idea was added to the pillow, which was naturally used for sleep, but could it add additional features for health care. Here, health care targets sleep apnea, which is known to be associated with serious illness. The purpose of this paper is to design a comprehensive service that uses a pressure sensor and a voice sensor to obtain information and to identify abnormal symptoms related to diseases from this information and to refer them to a specialist. It also covers the basic design and implementation to confirm the success of this system. Based on this design, the information obtained will be converted into a DB, and a server system for consultation with a specialist will be completed to upgrade the role of assistive health devices for sleep apnea.

• The Journal of the Korea Contents Association
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• v.17 no.5
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• pp.200-208
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• 2017

The purpose of this study was to examine the relationship of the severity, depression and to identify factors influencing quality of sleep in Restless Legs Syndrome(RLS) patients. A total of 303 consecutive RLS patients were assessed by self questionnaires and participant's medical records were reviewed for obtaining their clinical information. The collected data were analyzed by descriptive statistics, t-test, ANOVA, Pearson's correlation, and multiple regression. The quality of sleep was positively correlated with symptoms(r=. 21, p<.001) and depression(r=. 37, p<.001). The results of multiple regression analysis showed that significant variables influencing the quality of sleep were depression(${\beta}=.35$, p<.001), age(${\beta}=.21$, p<.001), and severity(${\beta}=.15$, p=.005). The explanation power of this regression model was 21.0% and it was statistically significant. As a result, to improve their sleep quality, the nursing interventions are required for RLS patients who have the depression, age, and severity.

• Journal of the Korean Applied Science and Technology
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• v.38 no.2
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• pp.399-410
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• 2021

This study is a descriptive research to provide the basis of program development for further dysmenorrhea relief by looking into identify the degree of perceived stress, depression, sleep disturbance, and dysmenorrhea in female university students, the relationship between these variables, and the factors influencing dysmenorrhea. We collected 160 data female university students who are attending J university. The study period lasted four weeks, going from Nov 11 to Dec 9. The correlated factors of dysmenorrhea included perceived stress(r=.420, p<.001), depression(r=.459, p<.001), sleep disturbance(r=.429, p<.001). The prevalent factors influencing dysmenorrhea are sleep disturbance, depression, perceived stress. Therefore, it will be needed to find ways and development of an intervention program to relieve perceived stress, reduce depression and enhance the sleep quality for female university students' dysmenorrhea relief.

• The Journal of the Convergence on Culture Technology
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• v.7 no.2
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• pp.297-302
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• 2021

This study was conducted to investigate the level of depression in the elderly after stroke and to determine the relationship between sleep quality and post stroke depression. The study participants were 110 elderly people aged 60 or older who visited the physical therapy room after stroke, and the survey was conducted from August to November 2020. Descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, and multiple regression analysis were performed for data analysis. As a result, 77.3% (85 patients) of the participants were depressed. The factor influencing on depression was the quality of sleep, and the explanatory power was 27.8%. It was confirmed that the sleep quality of the elderly after a stroke was a major influencing factor on depression. Therefore, it is thought that measures to improve the quality of sleep should be prepared in order to reduce the post stroke depression of the elderly.

• Journal of Digital Convergence
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• v.20 no.2
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• pp.553-561
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• 2022

The purpose of this study is to understand the relationship between anxiety, sleep disturbance, and suicide ideation in the elderly using senior welfare centers and to identify factors influencing suicide ideation. Data were collected from January 6 to February 7, 2020 from 206 elders who analyzed using SPSS/Win 25.0 with descriptive statistics, t-test, ANOVA, Pearson's correlation coefficients, multiple regression analysis. anxiety, sleep disturbance, suicide ideation were positively correlated. Meanwhile, factor affecting suicide ideation were anxiety(β=.215, p=.001), sleep disturbance(β=.383, p<.001) and the explanatory power of suicide ideation was 27.3%. Therefore, in order to prevent suicide ideation, it will be necessary to develop an intervention program to maintain qualitative sleep and lower anxiety levels.

• 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.

• Sleep Medicine and Psychophysiology
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• v.21 no.1
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• pp.29-32
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• 2014

Objectives: The aim of current study is to evaluate the relationship between sleep, suicide and serotonin using some scales and loudness dependence of auditory evoked potentials (LDAEP). Methods: Total 65 patients who met the criteria for major depressive disorder were enrolled in current study. The patients were divided into two subgroups according to their insomnia and a history of suicide attempts. The auditory event-related potentials were measured to evaluate LDAEP before beginning antidepressants. Results: The scores of total Beck Depression Inventory (BDI) and BDI item 9 (suicide) were higher in insomnia subgroup than non-insomnia subgroup (respectively, p=0.0033 and p=0.03). However, LDAEP did not differ each other. The subgroup with a history of suicide attempts had a higher score of BDI item 9 than the subgroup without a history of suicide attempts (p=0.00012). There was a tendency for the LDAEP to be higher in the subgroup with a history of suicide attempts ($1.39{\pm}0.94{\mu}V$) than the sub-group without a history of suicide attempts ($1.05{\pm}0.75{\mu}V$), although the difference was not statistically significant (p=0.078). Conclusion: Suicidality was related to insomnia. In addition, there was a tendency for serotonin activity to be lower in the subgroup with a history of suicide attempts. In future, more studies are needed.

• Tuberculosis and Respiratory Diseases
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• v.60 no.1
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• pp.76-82
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• 2006

Background : The objective of this study was to understand sleep-related problems, and to determine whether the sleep questionnaires is a clinically useful method in patients who need polysomnography. Methods : Subjects were patients who performed polysomnography and who asked to answer a sleep questionnaires at the Sleep Disorders Clinic of St. Paul's Hospital, Catholic University of Korea. Baseline characteristics, past medical illness, behaviors during sleep-wake cycle, snoring, sleep-disordered breathing and symptoms of daytime sleepiness were analyzed to compare with data of polysomnography. Results : The study population included 1081 patients(849 men, 232 female), and their mean age was $44.2{\pm}12.8years$. Among these patients, 38.9% had an apnea-hypopnea index(AHI)<5, 27.9% had $5{\leq}AHI<20$, 13.2% had $20{\leq}AHI<40$, and 20.0% had $40{\leq}AHI$. The main problems for visiting our clinic were snoring(91.7%), sleep apnea(74.5%), excessive daytime sleepiness(8.0%), insomnia(4.3%), bruxism(1.1%) and attention deficit(0.5%). The mean value of frequency of interruptions of sleep was 1.6 and the most common reason was urination(46.3%). Epworth Sleepiness Scale(ESS) had a weak correlation with AHI(r=0.209, p<0.01). When we performed analysis of sleep questionnaires, there were significant differences in the mean values of AHI according to the severity of symptoms including snoring, daytime sleepiness, taking a nap and arousal state after wake(p<0.05). Conclusion : On the basis of statistical analysis of sleep questionnaires, the severity of subjective symptoms such as ESS, snoring, daytime sleepiness and arousal state after wake correlated with the AHI significantly. Therefore the sleep questionnaires can be useful instruments for prediction of the severity of sleep disorder, especially sleep-disordered breathing.