• Sleep Medicine and Psychophysiology
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• v.7 no.2
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• pp.96-101
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• 2000

Objectives: Through comparing sleep variables and autonomic activities among three shifts in shift workers, the authors intended to clarify which shift is most tolerable and to identify the characteristics of their psychological and physical problems. This study is also expected to help shift workers to adapt themselves to their work more effectively. Methods: Fifty one shift workers took part in this study. They were working in a rapidly rotating system in which they worked for 3 days in one shift with one day off between each shift. Based on a sleep diary, sleep latency (SL), sleep period time (SPT), and number of wake after sleep onset (NWASO) were estimated and compared among the three shifts. In assessing sleepiness, Epworth sleepiness scale (ESS) and visual analogue scale (VAS) were used. To evaluate mood states among the three shifts, profile of mood states (POMS) was administered. Heart rate variability (HRV), and the level of adrenaline and noradrenaline were measured to assess autonomic activities. HRV included low frequency power (LF), high frequency power (HF), and LF/HF. Results: SPT was significantly lengthened during the evening shift and SL was shortened during the night shift. The workers showed a drop in alertness at wake-up during morning shift and a drop in alertness at work during night shift. During night shift the subjects complained of physical fatigue and cognitive decline. Comparison of HRV showed that parasympathetic activity was most prominent during the evening shift. Secretion of adrenaline and noradrenaline decreased during the evening shift, though statistically not significant. Conclusion: We found that the evening shift was most tolerable among the three shifts. It is recommended that morning light exposure be done during the morning shift and nocturnal light exposure during the night shift.

• Journal of the Society of Disaster Information
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• v.15 no.4
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• pp.548-559
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• 2019

Purpose: Analysis method of V2I data driven motorway service area usage behavior to cope with manpower survey. Method: Segmentation of traveling state group and boundary using the distribution characteristics of traveling speed data of individual vehicles. Result: As a result of the verification, the use rate of resting places in lunchtime surged, and the boundary between the distribution status of the traffic speed data was clearly or unclear. Conclusion: The effect of the cost reduction is big because it can cope with the use of rest area survey by manpower and there is no limit in the time and space range of investigation. The dynamic utilization rate of each time sequence, such as a service area/drowsiness shelter/simple service area, with a V2I system, can be calculated. Identify illegal parking on highway section. Identify the unexpected situation in the road section. Identify the real-time service area utilization rate and congestion information.

• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.333-339
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• 2008

When a vessel is underway in a heavy weather, passengers and crew suffer from seasickness caused by ship motions such as pitch, heave or roll, or all combined Sickness induces drowsiness, dizziness, headache, stomachache etc, in extreme conditions, they are met with a serious trouble which is physiologically unrecoverable. It results in weakening of spiritual activities or making errors from decrease of motivation, dropping off skills, poor recognition and poor judgement. In this paper, it was examined the international standards concerning the occurrence of sickness and the execution of works, also evaluated the boarding comfort by conducting several times of questionnaire on cadets boarding on the training ship HANBADA As a result, it was confirmed that the main factor of occurring the sickness was the vertical acceleration and the level was more than 0.2g. Also, it was presented the way how to reduce the sickness by changing the speed and/or course in relation to the encounter period.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.7078-7088
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• 2015

This study examined effects of health behaviors and sleep related factor on cognitive function in the elderly hypertensive patients. Data were collected through a face to face interview survey with structured questionnaire form 140 elderly with hypertension ($age{\geq}65years$) from February 5 to May 1, 2013. Research instruments included Pittsburgh Sleep Quality Index(PSQI), Epworth Sleepiness Scale(ESS) and Korean version the Mini-Mental State Examination(MMSE-K). Cognitive function was negatively related to degradation in quality of sleep(r=-.29, p<.001). Sleep duration were negatively related to body mass index(r=-.18, p=.032) and degradation in quality of sleep(r=-.59, p<.001). Sleep duration was positively related to daytime sleepiness(r=.22, p=.008). Hierarchical multiple regression showed that age, education levels and living arrangement were associated with cognitive function(F=8.56, p<.001, Adjusted $R^2=.14$). After controlling for demographic characteristics and health behaviors, degradation in quality of sleep(${\beta}=-.27$, p=.008) was identified as significant predictors of cognitive function. This final model explained 17.0% of the cognitive function in the elderly hypertensive patients(F=4.09, p<.001). Therefore, as a strategy improving cognitive function of the elderly with hypertension, therapeutic intervention should be developed to improve quality of sleep considering age, education levels and living arrangement.

• Journal of Korean Society of Transportation
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• v.23 no.2
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• pp.95-106
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• 2005

Road accidents are considered as the result of a complex interplay between road, vehicle, environments, and human factors. Little study, however, has been carried out on the attributes of human factor compared to the road geometric conditions and traffic conditions. The previous researches focused on mainly both traffic and geometric conditions on specific location. Therefore, it's hard to explain phenomenon of the high traffic accident rates where road and traffic conditions are good. Because of these reasons, accident analysis has contributed on geometric improvement and has not contributed on traffic management such as selection of attention section, driver napping alert, etc. The freeway incident management is also associated with reliable prediction of incident occurrences on freeway sections. This paper presents a method for estimating the effect of trip length on freeway accident rate. A PAR (Potential Accident Ratio), the new concept of accident analysis, considering TLFDs (Trip Length Frequency Distributions) is suggested in this paper. This approach can help to strengthen freeway management and to reduce the likelihood of accidents.

• Sleep Medicine and Psychophysiology
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• v.6 no.2
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• pp.126-132
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• 1999

Objectives: The purposes of this study were to investigate 1) the incidence of insomnia, 2) the clinical characteristics of the insomniacs, 3) the correlation of severity of insomnia with somatic complaints and psychological distresses, and 4) the beliefs and attitudes about sleep in patients with chronic renal failure on hemodialysis. Methods: The author evaluated 153 patients, receiving hemodialysis therapy at the four outpatients hemodialysis units in Pusan, Korea. The patients had completed a self-administered questionnaire package, which consisted of basic demographic findings, questions characterizing insomnia, Beck Depression Inventory(BDI), Spielburger's State-Trait Anxiety Inventory(STAI), and visual analogue scales measuring quantitatively the severity of the self-perceived psychological and somatic symptoms. And several laboratory data were collected. Diagnosis of insomnia was made in the base of insomnia criteria of DSM-IV and international classification of sleep disorders. Subjects were dichotomized into those who reported any characteristics of insomnia or those who had no insomnia during the preceding two weeks. Results: Insomnia was found in 100(65.4%) of 153 patients. No statistical differences were found between the patients with and without insomnia in terms of age, gender, education, marital status, mean duration of hemodialysis and all considered laboratory findings except serum albumin. The patients with insomnia had significantly higher BDI score and predialysis systolic blood pressure, and lower serum albumin as compared to non-insomnia group. Significant differences were found between two groups in terms of self-perceived distress such as sadness, anxiety, worry, pruritus, and dysfunction of daily life. The data showed statistically significant correlation between insomnia severity and some variables such as physical dysfunction, pruritus, bone pain, sadness, anxiety, worry, dysfunction of daily life and excessive daytime sleepiness. The patients with insomnia had significantly several dysfunctional beliefs and attitudes about sleep than those without insomnia. Conclusion: These results indicate that insomnia is very common in hemodialysis patients and likely contribute to the impaired quality of life experienced by many these patients. The author suggests that physical and psychological distresses would be reduced and the quality of life could be improved if their sleep disturbances are properly ameliorated in patients on hemodialysis.

• Sleep Medicine and Psychophysiology
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• v.9 no.1
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• pp.48-55
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• 2002

Objective: Stress is known to be a common cause of short-term insomnia and insomniacs often complain that stress induces sleep problems. However, previous studies on the correlation between stress and sleep do not show consistent results. We aimed to investigate the effects of minor stressful events on sleep among college students. Method: Physically and mentally healthy college student volunteers filled out a self-assessment questionnaire to evaluate their stress and sleep. To find out the status of average stress and sleep, the volunteers filled out K-DSI and daily sleep assessments on three consecutive days. In addition, we surveyed the amount of caffeine beverage intake and assessed the degree of depression and anxiety. Results: The total number of students participating in this study was 202, 101 men and 101 women. Minor stress turned out to significantly affect non-restorative sleep and secondary symptoms of insomnia (awakening difficulty, displeasure, feeling of dissatisfaction with sleep, physical uneasiness or pain at awakening, daytime sleepiness, depressive moods, tiredness and concentration difficulty). However, global PSQI score, self-reported sleeping hours, sleep latency, awakening frequency, frequency and duration of napping, were not explained by stress scores. Conclusion: In this study, minor stresses seemed to affect sleep, especially secondary symptoms caused by non-restorative sleep. We can thus infer that minor stresses impair the restorative effects of sleep by inducing arousal, and the direct relationship the two can be confirmed by polysomnogram.

• Journal of Hospice and Palliative Care
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• v.18 no.4
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• pp.314-321
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• 2015

Purpose: It is well known that a terminal cancer condition affects not only patient themselves but their family members because the patients experience a variety of symptoms. This study was aimed to investigate modifiable factors that influence family caregivers' quality of life, depression, and anxiety. Methods: From January 2015 through May 2015, a survey was conducted with 61 family caregivers of hospice patients who were hospitalized in two university hospitals and one municipal hospital in Busan. The questionnaire was consisted of characteristics of family caregivers and patients, the Korean version of the Caregiver Quality of Life Index-Cancer (CQOLC-K), Beck's Depression Inventory II (BDI-II), Beck's Anxiety Inventory (BAI), and patient's symptom controlling scores rated by family caregivers. Results: Family caregivers' depression was associated with religion. Quality of life and depression of family caregivers were also influenced by monthly household income. Patient age was inversely related to family caregiver's quality of life ($r_s=-0.259$, P=0.043). Family caregivers' quality of life was associated with patient's anxiety (r=0.443, P=0.001). Family caregivers' depression was affected by patient's constipation (r=0.276, P=0.046), anxiety (r=0.508, P<0.001), and daytime drowsiness (r=0.377, P=0.005). And family caregivers' anxiety was influenced by patients' sleep disturbance (r=0.276, P=0.046), depression (r=0.297, P=0.031), and anxiety (r=0.357, P=0.009). Conclusion: According to our findings, family caregivers had higher quality of life and less depression and anxiety when symptoms in hospice patients were well controlled.