• Safety and Health at Work
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• v.15 no.1
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• pp.53-58
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• 2024

Background: As social distancing persists and interest in work-life balance grows, more companies are adopting flexible work policies. While there have been studies on sleep disorders associated with different types of work, such as shift work, research exploring the relationship between flexible work schedules and sleep disorders is still limited, particularly among Korean workers. Methods: We performed a secondary analysis of the 6th Korean Working Conditions Survey, focusing on 31,243 paid workers out of a total of 50,538 participants. We defined flexible workers as those who set their own working hours. Sleep disorders were divided into three categories: 'difficulty falling asleep,' 'frequent waking during sleep,' and 'waking up feeling exhausted and fatigued.' Using scores derived from three specific symptoms, the Minimal Insomnia Symptoms Scale (MISS) was calculated to assess the prevalence of insomnia. We used chi-square tests to analyze demographic and job-related differences. A multivariate logistic regression analysis was employed to identify any relationship between flexible work schedules and sleep disorders. Results: Significant differences were found between flexible and non-flexible workers regarding age, income level, education level, and job type. Flexible workers reported sleep-related symptoms significantly more often. The odds ratio for insomnia was 1.40 (95% CI 1.21-1.61). For males, the odds ratio was 1.68 (1.36-2.08). Conclusion: This study establishes a correlation between flexible work schedules and sleep disorders among Korean salaried workers. Potential causes could include changes in circadian rhythm, increased work demands, and extended working hours. To precisely determine causality and associated diseases, further research is required.

• Journal for History of Mathematics
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• v.19 no.3
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• pp.123-146
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• 2006

The topic in this thesis stems from the current education situation that represses learners' freedom by excessive instruction and compulsory institution, in spite of the education helping learners free from inner prejudice as one of its chief aims. In this thesis, to discuss with an educational aspect, I call the learners' freedom in the learning process 'freedom-in-process' and the learners' freedom as the result of learning 'freedom-as-result'. Through this discussion, the conclusions are as follows; First, learners who enjoy freedom-in-process get to obtain freedom-as-result in mathematics education. Second, freedom-in-process and freedom-as-result appear repeatedly in the process of looking for and gaining structures. Freedom-in-process and freedom-as-result are both faces of coin, like seed and fruit which are related mutually and fertilized each other. For this purpose, Mathematics teacher must have awareness of the value of freedom, cherish the freedom, and enjoy it with his students.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.30 no.2
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• pp.58-66
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• 2007

This study is evaluation of shift-workers' sleep and social life related to hospital workers' performance and health. We researched shiftworkers' sleep, sleeping quality and social relations using a questionnaire method to shiftworkplace scattered Daejeon and Chungnam province. The results of shiftworkers' sleep are differ from habitual sleep. Social participations of shiftworkerse are interfered partially because of shiftwork. In preference, shiftworker preferred health to others because of physical load of shiftworks. Through result of this study about sleep and social life style, we hope to derive reduction methods of shift work fatigue and education for improvement of employers, for example an physiological and psychological accordance method, an health problem solving method and an social accordance method, etc.

• Journal of Fisheries and Marine Sciences Education
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• v.24 no.6
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• pp.854-861
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• 2012

To investigate the role of water temperatures and photoperidos as environmental cues regulating reproductive rhythm in banded catfish Pseudobagrus fulvidraco, rearing experiments were conducted using sveral rearing regimes conbined with changes in photoperiods and water temperatures during growing and spawning periods. GSI of $23^{\circ}C$ was significantly higher than $18^{\circ}C$ in female, but 9 light of 18 and $23^{\circ}C$ were no difference in male. In case of estradiol, $18^{\circ}C$ and 15 L was higher than other experintal precinct after 20 days. But, end of the experiment, all of experimental precinct were no difference. Testosteron of female was no difference in $18^{\circ}C$-9 and 15 L after 20 days. Testosteron of male was no difference in $18^{\circ}C$-9 L. In case of 11-KT, control level was $0.39{\pm}0.03$ ng/mL and $18^{\circ}C$-9 L was no significantly difference after 20 days. But, 15 L was higher than other experimental precinct.

• Sleep Medicine and Psychophysiology
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• v.19 no.2
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• pp.59-62
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• 2012

Borderline personality disorder (BPD) is characterized by identity and interpersonal problem, affective dysregulation and pervasive severe impulsivity. Although sleep disturbances are not primary symptoms of BPD, they are important aspects of this disorder. However, clinicians and researchers did not give much attention to the sleep symptoms of BPD yet. Measured by nocturnal polysomnography, increased sleep latency as well as reduced total sleep time and sleep efficiency, and 'depression-like' REM abnormalities (i.e., reduced REM latency and increased REM density) are found in BPD patients. Co-morbid sleep disorders such as chronic insomnia, nightmare disorder or circadian rhythm sleep disorder associated with BPD have been reported. Clinicians should focus on the sleep complaints of BPD patients, and carefully manage such symptoms with sleep hygiene education, cognitive psychotherapy or light therapy.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.4
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• pp.1068-1075
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• 2016

The suitable temperature and salinity for the long-distance transportation for the rockfish were investigated by assessing survival rate, metabolism, histological change. All experimental groups showed survival rates of 100%. Daily Oxygen consumption rhythm was decreased during nights and increased during days. Average oxygen consumption was significantly decreased as temperature and salinity were decreased. Ammonia excretion was significantly increased as temperature and salinity were decreased. Histological changes were observed in the skin and gill of the rockfish exposed to 10 psu under all the temperature conditions, with larger changes at $4^{\circ}C$. Further, nucleus deformation and uniformity in the cytoplasm were also observed.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.2
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• pp.63-71
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• 2005

There is a concern in the aviation community that pilot schedules can lead to fatigue and increased chance of an aviation accident. Yet despite this concern, there is little empirical studies showing the relationship between pilot fatigue and commercial aviation accidents. At this point of view, countering fatigue is a challenging proposition in complex aviation operations. However, with appropriate planning, many strategies can contribute to pilot alertness and flight safety. With proper education program, sustaining a physiological fit, a right knowledge about pilot fatigue can design a safety operations. On this study, I inquire into the ways of enhancing pilot's efficiency from fatigue.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.2
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• pp.124-132
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• 2020

This study examines the clinical availability of alpha amplitude, asymmetry and mean frequency in old age as EEG indexes reflecting brain health condition. The EEGs of prefrontal lobes in eye closure state were measured for 4 minutes with 72 male and female elderly people aged 73. Subjects were divided into higher and lower groups based on average values of alpha amplitude, asymmetry and mean frequency. The results of correlations and t-test among EEG indexes were as follows. First, the higher Alpha altitude was, the higher physical and mental stress resistance and left-to-right brain communication were, and the lower mean Alpha mean frequency location was. The higher Alpha asymmetry was, the lower left-to-right communication level was. Second, as Alpha power of right brain was higher than that of left brain, Alpha amplitude and mental stress resistance and left-to-right brain communication level were higher. Third, as Alpha mean frequency location was higher, Alpha amplitude and mental anti-stress level were lowered and arousal level was enhanced. These high correlations and complementary meaning among quantitative EEG indicators demonstrated the possibility of biomarkers reflecting brain health state in old age.

• Journal of Music and Human Behavior
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• v.11 no.2
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• pp.1-18
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• 2014

This study investigated the performance patterns in percussion improvisation of adolescents with behavior problems. A total of 40 middle school students participated in this study. Based on prescreening test results, the participants were assigned to either the impulsive tendency or depressive tendency groups. Both groups received two 45-minute group percussion improvisation. During the improvisation, all playing behaviors were recorded and analyzed in terms of rhythm pattern, instrument selection, intensity, and tempo of performance and performance duration. The results showed that while they were differences in improvised rhythm patterns between the two groups, the groups showed a similar tendencies in their instrument selection. With regard to performance parameters, the two groups showed significant difference in the tempo and duration of performance, but no significant difference was found in terms of intensity. This indicates that adolescents who exhibit behavior problems may be different in their playing patterns depending on their behavioral tendencies. Based on the results, music therapists can have a better understanding of how musical features expressed by this population relate to their inherent emotional and behavioral traits and how therapists should facilitate musical expression of these adolescents to address their needs.

• Journal of the Korean Dietetic Association
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• v.29 no.2
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• pp.86-99
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• 2023

In this study, the authors surveyed the dietary habits of all elementary school students registered with the Busan Metropolitan City Office of Education using an online questionnaire called the Dietary Screening Test (DST). The DST consists of 36 items, and these were divided into 5 factors: life rhythm, meal quality, eating development, eating temperament characteristics, and eating habit characteristics. Data were collected from 153,017 students attending 304 schools in Busan, and the responses of 4,020 were included in the analysis. The study was undertaken to document growth and development and diagnose nutrition and dietary problems to provide basic data for the development of customized nutrition education and counseling programs. Results showed that 13.5% and 14.3% of participants were classified as overweight or required weight management for obesity, respectively; 6.7% were underweight. Additionally, 37.0% and 9.5% of children required parental attention at bedtime and sleeping hours, and 14.2% ate too quickly or too slowly. Furthermore, food group consumptions were unbalanced, 25.0% and 64.4% of participants ate grains and protein less than twice a day, respectively, and 72.3% and 74.5% ate kimchi and vegetables less than twice a day, respectively. In contrast, 28.8% of respondents consumed sweet snacks daily or 5~6 times weekly. These findings highlight the need for a standardized school nutrition counseling manual and individually customized nutrition counseling programs to address the nutrition and dietary problems of elementary school students in Busan.