• Journal of Korean Academy of Fundamentals of Nursing
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• v.19 no.4
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• pp.425-433
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• 2012

Purpose: The purpose of this study was to investigate sleep patterns and predictors of excessive daytime sleepiness (EDS) in university students. Methods: Participants were 120 university students who were attending two universities in S-city and C-city. Data were collected from May 20 to June 15, 2012 using self-report questionnaires which included Johns' Epworth Sleepiness Scale, Yi's Sleep Quality Scale, and Beck Depression Inventory. Data were digitalized and analyzed using frequency, percentages, means and standard deviations, Wilcoxon rank sum test, Chi-square test, Fisher's exact test, and multiple logistic regression with SAS 9.0. Results: Mean total sleep time was 6.6 hours on weekdays, 8.1 hours on weekends. Mean sleep latency was 19.1 minutes and the score for mean sleep quality was 22.6. Prevalence of EDS was 12.5%. Depression was significantly different between EDS and Non-EDS students (t=2.17, p=.030). Multiple logistic regression showed that the only factor associated with EDS was depression (adjusted odds ratio of depression=5.33, 95% Confidence Interval=1.49-19.04). Conclusion: Results of this study indicate that university students experience short sleep time, low sleep quality, and common EDS with depression, suggesting that students with complaints of EDS should be completely assessed for depression as well as sleep problems.

• Journal of Korean Critical Care Nursing
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• v.13 no.3
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• pp.1-10
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• 2020

Purpose : This study aims to investigate the differences in fatigue, sleepiness, and near-miss according to sleep disturbance among shift nurses in intensive care units (ICUs). Methods : A cross-sectional study in a tertiary hospital was performed. A total of 122 shift nurses working in the six ICUs were recruited. They completed self-reported questionnaires about sleep disturbance, fatigue, sleepiness, and near-miss in the past two weeks. Results : The prevalence of reported sleep disturbance was 30.3% (37 out of 122 subjects). Compared to the non-sleep disturbance group, the sleep disturbance group reported significantly more sleepiness (11.46 vs. 8.86) and higher fatigue (82.62 vs. 69.39). The sleep disturbance group showed higher rates of near-miss (78.4 vs. 57.6%) and a higher frequency of them (4.49 vs. 2.11/2weeks) compared to the non-sleep disturbance group. Medication error was the most common type of near-miss. Conclusions : This study suggests that sleep disturbances could increase fatigue, sleepiness, and near-miss among ICU shift nurses. Personal and organizational programs should be developed to support the sleep of ICU nurses.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.3
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• pp.134-141
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• 2017

The purpose of this study was to analyze physiological changes via a cold air reaction experiment to generate basic data that are useful for the development of an automobile active air conditioning system to prevent drowsiness. The $CO_2$ concentration causing drowsiness in vehicle operation was kept below a certain level. Air was blown to the driver's face by using an indoor air cooling apparatus. Sleepiness and the arousal state of the driver in cold wind were measured by physiological signals. It was evident in the EEG that alpha waves decreased and beta waves increased, caused by cold air stimulation. The ${\alpha}/{\beta}$ ratio was reduced by about 52.9% and an alert state confirmed. In the electrocardiogram analysis, the efficiency of cold air stimulation was confirmed by the mean heart rate interval change. The R-R interval had a delay time of about one minute compared to the EEG response. The findings confirmed an arousal effect from sleepiness due to cold air stimulation.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.11
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• pp.90-94
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• 1996

We studied the problem of driver's low vigilance state which is related to the one reason of traffic accidents. In this paper, we developed the drowsiness warning system for a drowsy driver. To extract the eyes and mouth from the driver's facial image in real time, a computer vision method was used. The eye blink duration and yawning were used as measurement parameters of drowsiness detection. When the drowsy state of a driver was detected, the driver was refreshed by the scent generator and the alarm. Also, the driver's bio-signal was acquired and analyzed to measure the vigilance state.

• Proceedings of the Korea Information Processing Society Conference
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• 2020.11a
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• pp.1090-1093
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• 2020

운전자가 아닌 자율주행 시스템이 운전을 주도하기 위한 기술의 상용화를 위해 많은 기업이 노력 중이다. 특히 운전자의 안전을 보장하기 위한 운전자와 자율주행 시스템 간의 제어권전환이 중요하다. 운전자의 주행과 관련 없는 행동은 제어권전환 상황에서 운전자를 위험에 빠뜨릴 수 있으므로 제어권전환을 돕기 위한 운전자 모니터링 기술에 관한 많은 연구가 진행되고 있다. 운전자 모니터링 기술은 주로 생체 정보, 차량 정보, 영상을 사용하여 운전자의 상태와 부주의 행동 등을 감지하는 기술이다. 최근 머신 러닝, 딥 러닝을 사용한 영상처리 및 인식 기술 등의 발전으로 영상을 사용한 운전자 모니터링 기술이 활발하게 연구되고 있다. 따라서 본 논문에서는 영상기반 운전자 모니터링 기술 동향에 대해 상세히 기술하였다. 특히 운전자의 부주의 행동 중 졸음은 운전자가 주행 상황을 전혀 인지하지 못하게 할 수 있어 더욱 위험한 행동이다. 따라서 영상기반 운전자 모니터링 기술을 졸음 인식과 그 외의 행동 인식으로 분류하여 동향을 정리하였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.18 no.6
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• pp.754-761
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• 2008

As the automobile industry and technologies are developed, driver's tend to more concern about service matters than mechanical matters. For this reason, interests about recognition of human knowledge and emotion to make safe and convenient driving environment for driver are increasing more and more. recognition of human knowledge and emotion are emotion engineering technology which has been studied since the late 1980s to provide people with human-friendly services. Emotion engineering technology analyzes people's emotion through their faces, voices and gestures, so if we use this technology for automobile, we can supply drivels with various kinds of service for each driver's situation and help them drive safely. Furthermore, we can prevent accidents which are caused by careless driving or dozing off while driving by recognizing driver's gestures. the purpose of this paper is to develop a system which can recognize states of driver's emotion and attention for safe driving. First of all, we detect a signals of driver's emotion by using bio-motion signals, sleepiness and attention, and then we build several types of databases. by analyzing this databases, we find some special features about drivers' emotion, sleepiness and attention, and fuse the results through Multi-Modal method so that it is possible to develop the system.

• Sleep Medicine and Psychophysiology
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• v.9 no.2
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• pp.122-126
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• 2002

Objectives: The purpose of this study is to investigate the effects of the 37-hour sleep deprivation on visual discrimination using the Cybernetic Flicker Fusion Analyzer (FLIMK) and to see the correlation between this finding and various subjective scale scores. Methods: Twenty six subjects (20 men 6 women, $24.50{\pm}1.45$ years of age) participated in this study. Subjects remained awake for 37 hours under continuous surveillance. In the morning and evening of two study days, the FLIMK and the self-reporting scale of sleepiness, fatigue, anxiety and mood states were instituted. Results: In FLIMK, the flicker fusion threshold was significantly decreased after sleep deprivation (F=7.66, p=0.01). The number of trials (responses) before reaching fusion frequency threshold was significantly increased after sleep deprivation (F=13.16, p=0.001). The reduction of fusion frequency was correlated with the increase of sleepiness and fatigue (p<0.05), and the number of the trials was correlated with the scores of negative mood, anxiety, and fatigue (p<0.05). Conclusions: These results suggest that 37 hour total sleep deprivation cause the decrement in visual discrimination. The decrease of the fusion frequency after sleep deprivation was correlated with sleepiness and fatigue. Further study is needed to enlighten the biological mechanism of the decrement in visual function after sleep deprivation.

• Journal of Korean Society of Transportation
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• v.34 no.4
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• pp.341-353
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• 2016

Highway is mainly in charge of middle-long distance of vehicular travel. Trip length has shown a growing trend due to increased commute distances by the relocation of public agencies. For this reason, the proportion of driver-driven accidents, caused by their fatigue or sleepiness, are very high on highways. However, existing studies related to accident prediction have mainly considered external factors, such as road conditions, environmental factors and vehicle factors, without driving behavior. In this study, we suggested an accident index (FDR, Fatigued Driving Rate) based on traffic behavior using large-scale Car Navigation path data, and exlpored the relationship between FDR and traffic accidents. As a result, FDR and traffic accidents showed a high correlation. This confirmed the need for a paradigm shift (from facilities to travel behavior) in traffic accident prediction studies. FDR proposed in this study will be utilized in a variety of fields. For example, in providing information to prevent traffic accidents (sleepiness, reckless driving, etc) in advance, utilization of core technologies in highway safety diagnostics, selection of priority location of rest areas and shelter, and selection of attraction methods (rumble strips, grooving) for attention for fatigued sections.

• Sleep Medicine and Psychophysiology
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• v.26 no.1
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• pp.16-22
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• 2019

Objectives: The objective of this study was to investigate the correlation between insufficient sleep and visuospatial memory in adolescents using a computerized neurocognitive function test. Methods: A total of 103 high school students (26 males and 77 females; mean age $17.11{\pm}8.50years$) without a serious psychiatric problem was recruited. All subjects were requested to complete a self-report questionnaire about weekday total sleep time and weekend total sleep time. The epworth sleepiness scale (ESS) and the beck depression inventory (BDI) were administered to measure daytime sleepiness and symptoms of depression. Seven subsets of the Cambridge Neuropsychological test automated battery were examined to assess visuospatial memory. Results: After controlling for age, sex, ESS, and BDI, longer weekend total sleep time was correlated with poor performance on delayed matching to sample (r = -0.312, p = 0.002) and immediate recall on pattern recognition memory (r = -0.225, p = 0.025). Increased weekend catch-up sleep time was correlated with poor performance of delayed matching to sample (r = -0.236, p = 0.018), immediate recall on pattern recognition memory (r = -0.220, p = 0.029), and delayed recall on pattern recognition memory (r = -0.211, p = 0.036) after controlling for age, sex, ESS, and BDI. Conclusion: This study showed that increased weekend catch-up sleep time reflecting insufficient weekday sleep were associated with poor performance in delayed recall tasks of visual memory. This finding suggests that insufficient sleep during adolescence might produce a decline of visuospatial memory.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.533-541
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• 2022

An analysis of marine accidents that occurred in the last five years, revealed that 77.0 % of all grounding accidents and 66.1% of all marine casualties involved small vessels, which was a very high level relatively. The Mokpo Regional Maritime Safety Tribunal (Mokpo-KMST) inquired on 72 cases of marine accidents in 2021, of which 10 cases were grounding accidents. Furthermore, eight cases of grounding accidents occurred in small fishing vessels. This study analyzed eight cases of grounding accidents on small fishing vessels that inquired in the jurisdictional area of Mokpo-KMST in 2021. I found out that this grounding occurred in clear weather with good visibility (2-4 miles) and good sea conditions with a wave height of less than 1 meter. Furthermore, I found that the main causes of grounding were drowsy navigation due to fatigue, neglect of vigilance, neglect of checking ship's position, overconfidence in GPS plotter, and lack of understanding of chart symbols and tidal differences. To reduce grounding accidents of small fishing vessels, I suggested the following measures. First, crew members who have completed the able seafarer training course on bridge watchkeeping should assist to the master. Second, alarm systems to prevent drowsiness should be installed in the bridge. Third, the regulation should be prepared for the performance standards and updating GPS plotter. Finally, the skipper of small vessels should be trained periodically to be familiar with chart symbols and basic terrestrial navigation.