• Journal of Korean Academy of Nursing
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• v.21 no.2
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• pp.129-149
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• 1991

Circadian rhythm is entrained in the 24-hour time interval by periodic factors in the environment, known as zeitgeber. But most rotating work schedules are outside the range of the entrainment of the pacemaker timing the human circadian sleep - wake cycle. It has been postulated that physiological and emotional disturbances occur in most human functions when the circadian rhythm is disturbed. So application of circadian principles to the design of shift schedules can aid in maintaining the temporal integrity of the circadian system and thereby minimize for the shift worker any detrimental consequences of circadian disruption. This study was a quasi-experimental study to test the effect of shift intervals for the clinical nurse on the circadian rhythm. Twenty nurses newly employed in general units of two hospitals were selected as an experimental group and twelve college nursing students as a control group. Both groups were selected according to an established criteria using a purposive sampling technique. Ten subjects were assigned to a weekly shift group and another ten to a biweekly shift group engaged in a semi -continuous shift schedule(sunday off) with a backward direction, that is, morning -evening - night shift. The control group worked a morning shift for 42 days. Oral temperature rhythm, waking tim, sleep - wake cycle, fatigue, and mental performance were measured during the experimental period. The data collection period was from April 30, 1990 to June 10, 1990. MANOVA, paired t-test, ANOVA, and Student Newman Keuls method were used for statistical analysis. The results are summarized as follows. 1. Phase delay in the acrophase of temperature rhythm was shown according to the backward rotating shift. A complete adaptation to work on the night shift was achieved between the sixth and ninth day of the night shift. 2. There was no difference in either waking time or sleep- wake cycle according to the duration of the working day for every shift group. Significant difference was found in the waking time and the sleep -wake cycle for subjects on the morning, evening, and night shift in both of the shift groups(weekly shift group : λ＝0.121, p＜0.01, λ＝0.112, p＜0.01, biweekly shift group : λ＝0.116, p＜0.01, λ＝0.084, p＜0.01). 3. There was no difference in fatigue between the first working day and the last working day for the control group and for the biweekly shift group. In the weekly shift group, physical fatigue was significantly different for the first day and the sixth day of the night shift(t＝-2.28, p＜0.05). Physical fatigue and total fatigue on the first day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝5.79, p＜0.01, F＝4.56, p＜0.05). There was a significant difference between the shift groups and the control group(p＜0.05), Physical fatigue, neurosensory fatigue and total fatigue on the last day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝12.65, p＜0.01, F＝7.77, p＜0.01, F＝9.68, p＜0.01). There was a significant difference between the shift groups and the control group(p＜0.05). 4. No difference in mental performance was seen between the first day and the last day of work in each case. An arithmatic test on the first day of the night shift revealed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝3.79, p＜0.05). There was a significant difference between the shift groups and the control group(p＜0.05) . The digital symbol substitution test and the arithmetic test on the last day of the night shift showed a significant difference among the control group, the weekly shift group, and the biweekly shift group(F＝3.68, p＜0.05, F＝5.55, p＜0.01), and both showed a significant difference between the shift groups and the control group(p＜0.05). Accordingly, this study showed that during night duty, the waking time, sleep- wake cycle, and fatigue increased and mental performance decreased compared with morning and evening duty. It was also found that the weekly shift group had a higher fatigue score on the sixth day of night duty as compared to the -first day, but the waking time, sleep- wake cycle, and mental performance revealed no difference for the duration of the night duty or between shift groups, and complete adaptation of temperature rhythm was achieved between the sixth and ninth day of night duty. It is possible to conclude from these results that for intermediate circadian type in a healthy young woman, a biweekly shift system is more compatible with the circadian timing system than weekly shift system.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.6B
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• pp.342-349
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• 2007

Clustering protocol of Wireless sensor networks(WSNs) not only reducing the volume of inter-node communication by the nodes's data aggreation but also extending the nodes's sleep times by cluster head's TDMA-schedule coordination. In order to extend network lifetime of WSNs, we propose ECS algorithm to select cluster-head using three variables. It consists of initial and current energy of nodes, round information and total numbers which have been selected as cluster head until current round.

• Journal of Oriental Neuropsychiatry
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• v.15 no.2
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• pp.221-228
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• 2004

Many literature-based researches have been thus far reported of Hwa-Byung in oriental medicine and Hwa-Byung is considered as culture-bound syndrome of Korea. It is showed practically middle-aged women and connected with emotion of Han(恨)and its progress generally chronic. But this case described a 36-year old man who diagnosed as Hwa-Byung by HBDIS. He complained chiefly headache and suffered from chest discomfort and sleep disorder. After acupuncture teatment, herbal medication and oriental psychotherapy, his condition got improved. This report is for better understanding of this disease, that Hwa-byung can be seen in male according to changes of social environment.

• Fashion & Textile Research Journal
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• v.15 no.2
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• pp.277-285
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• 2013

This study examines the wearing comfort of elderly women through a physiological analysis based on rectal temperature and biochemical analysis with salivary melatonin and cortisol. This study was conducted on 7 elderly women aged 65 or over. Two kinds of clothing ensemble (control and prototype) were used as experimental clothing. The control clothing was a general clothing ensemble and the prototype clothing lowered clothing pressure by adding an extra gap. The experimental schedule included daily living activities with randomly assigned experimental clothing. Rectal temperature was constantly measured every 5 minutes during the experiment and saliva samples for melatonin and cortisol were collected twice per day before and after sleep. The rectal temperature was lower for the prototype than the control throughout the experiment, and its circadian rhythm was prompt and clear in prototype. In addition, melatonin was secreted more but cortisol was secreted less when the subjects wore the prototype clothing. With these results, we assumed that regular circadian rhythm and low level of stress might be caused by wearing prototype clothing that lowered clothing pressure. The results demonstrate the necessity to develop clothing that considers body changes in elderly women.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.5 s.143
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• pp.516-527
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• 2005

It has been estimated that up to $80\%$ of all marine accidents have human elements as a cause. Out of these, human elements of crew fatigue is one of the main causes of marine accident. Crew fatigue involves sleep, schedule, workload, off-time, alcohol, health and stress. With a ship handling simulator, the effect of alcohol on ship operational performance is studied for each 0.05 and 0.08 $\%$ blood alcohol concentrations(BAC). The main effect of alcohol was found that ship operational performance was significantly impaired by alcohol compared to that in the non-alcohol condition. The results of this research can be used as basic data to minimize marine accidents.

• Journal of the East Asian Society of Dietary Life
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• v.18 no.1
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• pp.111-126
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• 2008

The purpose of this study was to examine the dietary habits and nutrient intakes of school-aged children participating in extracurricular classes, to with regards to class schedule. Three-hundred and two students from Seoul were selected and classified into two groups. One group attended extracurricular classes less than 12.43 hours per week, which was determined as the average number of hours per week(AELT, n=147). The other group attended extracurricular classes more than 12.43 hours per week(AEMT, n=155). The average student age in both the AELT and AEMT groups was 11.9 years, respectively. In terms of height and weight, there were no significant differences between the two groups. AELT received significantly more hours of sleep than AEMT(p<0.01), and there were significantly more responses with regard to lack of sleep in the AEMT group than in the AELT group(p<0.05). In a survey on 17 clinical symptoms regarding health, the AEMT group had significantly higher response rates than the AELT group in the following sections: no appetite (p<0.001), dizziness(p<0.001), headache(p<0.01), tiredness(p<0.01), cold symptoms(p<0.05), and sore eyes(p<0.05). Meal time irregularity was significantly higher than AEMT than in AELT(p<0.05). Approximately 50% of the subjects were picky eaters, and 40% and 20% skipped breakfast or dinner, respectively. The average energy intakes for AELT and AEMT were 2122.2 kcal and 2061.5 kcal, respectively, and there was no significant difference between the two groups. AEMT consumed significantly lower quantities of protein, animal fat, vitamin $B_6$, calcium, and phosphorus(each p<0.05) as compared to the AELT group. Beverage intake was significantly higher in AEMT than AELT(p<0.05). The number of hours in extracurricular classes showed a significant negative correlation with the intakes of protein, animal protein, animal fat, vitamin $B_6$, folate, calcium, plant calcium and phosphorus(each p<0.05). The number of hours in extracurricular classes also showed a significant negative correlation with soy foods intake(p<0.05). These results suggest that continuous and systematic nutritional education should be performed in order to prevent and improve the unbalanced diets and problematic of dietary habits that may result in students due to attendance in extracurricular classes.

• Proceedings of KOSOMES biannual meeting
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• 2004.11a
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• pp.49-56
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• 2004

It has been estimated that up to $80\%$ of all marine accidents have human elements as a cause. t of these, human elements of crew fatigue is main causes of marine accident. Crew fatigue involves sleep, schedule. workload. off-time. alcohol health and stress. With a ship handling simulator, the effect of alcohol on ship operational performance is studied for each 0.05 and $0.08g\%$ blood alcohol concentrations. A main effect for alcohol was found indicating that ship operational performance was significantly impaired by this alcohol relative to performance in the non-alcohol condition. The results of this research can be applied to minimize marine accidents as basic data.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6495-6503
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• 2015

The purpose of the study was to evaluate patients' compliance with the hemodialysis and to investigate relationships between compliance, physiological parameters, and health-related quality of life. Data were collected from 220 patients at 27 local hemodialysis clinics. Compliance was measured with Sick-role Behavioral Compliance including interdialytic weight gain, serum potassium, and phosphorus. Health-related quality of life was assessed using Medical Outcomes Study Short Form-12. Data were analyzed using descriptive statistics, t-tests, ANOVA, and Pearson correlation. Total compliance scored 2.92 out of 4 points on average. Among fifteen items, 'I keep on my dialysis schedule(time and date)' was the highest score. There were differences in the scores for compliance according to age, marital status, and dialysis period. Statistically significant correlations were found between four compliance items(medication, infection control, sleep, eating vegetable and fruit) and health-related quality of life. The results of the study indicate that a patient-centered approach would be helpful to improve quality of life in patients with hemodialysis. Healthcare providers need to understand the patients' perspectives by identifying what is important to patients and taking patient values and priorities into account.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.213-216
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• 2007

The paper deals with a approach to underwater acoustic based Ad-hoc communication, which allows major design strategies for Media Access Control (MAC) within a group of the autonomous underwater vehicles(AUV). The proposed MAC aims at deploying AUV-centric star topology, which minimizes overhead of sensor nodes and improves energy-efficiency. Furthermore, that is also well under long and unknown propagation delays of the underwater acoustic medium. The implemented MAC protocol makes it easier to achieve frame synchronization than TDMA due to deploying localized schedule time, in addition to saving energy consumption by letting nodes sleep. It is also superior to MACA and MACAW in terms of propagation delay. This scalable centralized protocol has the potential to serve as a primer for development of MAC protocol for future underwater acoustic based ad-hoc networks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.12A
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• pp.994-1005
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• 2011

In this paper, we propose a novel approach to optimize the movement of mobile sink node, called AMSP(Adaptive Mobile Sink Path) for mobile sensor network environments. Currently available studies usually suffer from unnecessary data transmission resulting from random way point approach. To address the problem, we propose a method which uses the Hilbert curve to create a path. The proposed method guarantees shorten transmission distance between the sink node and each sensor node by assigning orders of the curve according to sensor node density. Furthermore, The schedule of the sink node is informed to all of the sensing nodes so that the Duty Cycle helps the network be more energy efficient. In our experiments, the proposed method outperforms the existing works such as TTDD and CBPER by up to 80% in energy consumption.