• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.8
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• pp.2675-2690
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• 2014

We study the problem of optimal opportunistic spectrum access with unknown and heterogeneous channel dynamics in cognitive radio networks. There is neither statistic information about the licensed channels nor information exchange among secondary users in the respective systems. We formulate the problem of maximizing network throughput. To achieve the desired optimization, we propose a win-shift lose-stay algorithm based only on rewards. The key point of the algorithm is to make secondary users tend to shift to another channel after receiving rewards from the current channel. The optimality and the convergence of the proposed algorithm are proved. The simulation results show that for both heterogeneous and homogenous systems the proposed win-shift lose-stay algorithm has better performance in terms of throughput and fairness than an existing algorithm.

• Journal of Industrial Convergence
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• v.19 no.5
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• pp.119-128
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• 2021

This study was performed to improve the working conditions of female nurses by comparing their organizational commitment and turnover intention according to the type of work shift they prefer. This study is a descriptive survey study, and data were collected by conducting an online survey of 465 female nurses working in three shifts at seven medical institutions. The collected data were analyzed using SPSS WIN 24.0 in a χ² test, a two-sample independent t-test, a pearson correlation and MANCOVA. The result shows that the group of nurses preferring fixed work shift had higher organizational commitment at higher ages and had higher turnover intention if they had an experience of transferring to another medical institution. The study also found that the group that prefers fixed work shift had lower organizational commitment and higher turnover intention than the group of nurses preferring shift work. The nursing department in hospital should strive to improve the working environment in female nurses by developing various types of work, with an aim to increase the organizational commitment of female nurses preferring fixed work and reduce their turnover.

• Journal of Korean Institute of Industrial Engineers
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• v.25 no.4
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• pp.476-489
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• 1999

This paper is concerned with the deployment of core technologies for automotive steel sheets, based on the structural change of global market. The main tasks of automotive industry are to ensure the energy consumption, environmental regulations, and driving safety. With social and legal requirements, this study analyzes the market creation processes with technological innovations for hot rolled, cold rolled and galvanized steel sheets during the 20th century. It has been proven that the leading country in the steel industry was also that in the automotive. The purchaser-supplier relations of sheet materials are then patternized in the regional markets of the United States and Japan, who share nearly 50% of market in the world. According to the paradigm shift of globalization, the balance of power in Porter's 5 forces has been moved to the buyers', and both industries pursue Win-Win strategies such as the PNGV(Partnership for a New Generation of Vehicles ) and design-in system with the competition.

• Asian-Australasian Journal of Animal Sciences
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• v.8 no.2
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• pp.145-149
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• 1995

Validity of use of a Y-maze for determining a foraging strategy of cattle was investigated with the object of establishing a procedure of testing foraging strategies of large herbivores. Cattle were placed in a start box of a Y-maze, forced into either goal arm and allowed to consume half of the feed at the end of the arm. Then, cattle were returned to the start box and allowed to choose either arm in the second half of a trial. This time animals were allowed to deplete the feed in the goal arm they chose. A return to the previous arm was recorded a "stay" Choice of the other arm was recorded as a "shift". Shift strategy was not observed. Rather, their behavior appeared either random or stay. However, it might have been caused by inappropriateness of the application of the apparatus and/or the procedure used in the study of foraging behavior of rats. Although the existence of lateral preference was suggested, further study with an elaborated procedure will be necessary to investigate foraging strategies of cattle.

• Journal of Korean Biological Nursing Science
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• v.22 no.4
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• pp.308-316
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• 2020

Purpose: This study aimed to explore the knowledge and performance of sleep hygiene among nurses with shift work schedules and examine the influence on sleep disturbance. Methods: A total of 199 shift-work nurses from a tertiary hospital were included in the study. To examine the knowledge and performance of sleep hygiene, the participants were asked to respond to a self-reported survey. To assess sleep disturbance, the General Sleep Disturbance Scale was used. Descriptive statistics and multiple linear regression were applied using the SPSS/WIN 21.0 program to analyze the data. Results: Both the knowledge and performance of sleep hygiene among nurses with shift work schedules were measured at a moderate level. Nurses' knowledge and the performance of sleep hygiene was not significantly associated with sleep disturbance, whereas age, experience with shift-working, and perceived health status were significantly associated. Conclusion: Strategies for providing more accurate information and motivating better sleep hygiene would help to enhance sleep hygiene in nurses with shift work schedules. Further studies examining the association of knowledge and the performance of sleep hygiene with sleep disturbances in nurses with shift work schedules are needed.

• Journal of Korean Academy of Nursing Administration
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• v.13 no.1
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• pp.32-39
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• 2007

Purpose: This study is conducted to compare and analyse the health status and job satisfaction of nurses. Method: The subjects were a group of 90 nurses on fixed day nurse and the other group of 100nurses on night nurse. The collected data were analysed by using the SPSS WIN(10.0) program for descriptive statistics, t-test, ${\chi}^2-test$, ANOVA, and Pearson correlation coefficient. Result: There was a significant difference according to years in services. In nurses on day shift, there was a inverse correlation between the health status and job satisfaction. And in nurses on day shift, job satisfaction levels differed significantly depending on personality, satisfaction to pay, and current health status. In nurses on night shift, nurses' job satisfaction levels differed significantly depending satisfaction to pay. Conclusion: It was confirmed that health of nurses is greatly affected by shift work. so, it is very important to maintain and promote their health status in nurses on night shift. We must find out the factors that greatly affect health of nurses, and continuously make an effort to improve the working environment.

• Journal of Korean Academy of Nursing
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• v.48 no.5
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• pp.622-635
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• 2018

Purpose: This study aimed to develop and test a structural model for sleep quality in female shift work nurses. The hypothetical model was constructed on the basis of Spielman's 3P model of insomnia and previous research related to the sleep quality of shift nurses. Methods: This cross-sectional study used structural equation modeling and recruited 285 female shift work nurses from four general and university hospitals with over 300 beds located in C and J cities in Gyeongsangnamdo. Data were collected from September 27 to October 20, 2016, and then analyzed using descriptive statistics, Pearson's correlation, and structural equation modeling. The study used SPSS/Win 18.0 and AMOS 18.0 in processing the data. Results: The final model showed good fit to the empirical data: ${\chi}^2/df=2.19$, SRMR=.07, RMSEA=.07, AGFI=.85, TLI=.91, GFI=.93, GFI=.89, NFI=.87. The factors that influenced sleep quality were sleep hygiene (${\beta}=.32$), perceived shift work status (${\beta}=-.16$), stress response (${\beta}=.16$), shift work experience (${\beta}=.15$), perceived health status (${\beta}=-.14)$, and circadian rhythm (${\beta}=-.13$) explaining 36.0% of the variance. Conclusion: The model of sleep quality of the shift work nurses constructed in this study is recommended as a model to understand and predict the sleep quality of shift work nurses. The results suggest that strategies for improving the sleep quality of shift work nurses should focus on sleep hygiene, perceived health status, stress response, circadian rhythm, perceived shift work status, and shift work experience.

• Korean Journal of Occupational Health Nursing
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• v.20 no.1
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• pp.74-82
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• 2011

Purpose: This study investigated how shift work nurses' fatigue influences job stress and turnover intention, and how job stress mediates the relationship between fatigue and turnover intention. Methods: As a descriptive research design, the data were collected from 203 shift work nurses in a city. It was analyzed using the SPSS/WIN 14.0 and AMOS 5.0. Results: fatigue and job stress in shift work nurses influenced turnover intention. Job stress worked as a partial mediation between fatigue and turnover intention. Conclusion: It is necessary to reduce fatigue and job stress for reducing turnover intention in strategies of hospital manpower.

• Korean Journal of Adult Nursing
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• v.24 no.1
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• pp.11-19
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• 2012

Purpose: The purpose of this study was to explore the effect of an environmental intervention on sleep, reported emotions and job satisfaction of rotating shift nurses in intensive care unit. Methods: The study was a non-equivalent design with a comparison group. The participants in the study were 34 shift workers randomly assigned to one of two groups. The intervention for one group was the use of an eye shield for two weeks with the other group not receiving the treatment. Data on quality of sleep, stress, depression and job satisfaction were collected from both groups at the beginning and the end of the two week period. See note at bottom page. Data were analyzed by ANCOVA using the SPSS/WIN 18.0. Results: Quality of sleep and job satisfaction were more positively reported along with reports of less depression and stress by those nurses receiving the eyeshild intervention. Conclusion: These results suggest that the eyeshield intervention may be an effective intervention.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.6
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• pp.546-559
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• 2016

This study was conducted to analyze the relationship between sleep quality, stress response, physical activity and sleep hygiene in shift work nurses and identify factors influencing sleep quality. The participants were 168 shift nurses from university hospitals and general hospitals located in C city, Gyeongnam. Data were collected from March 25 to 31, 2016. The study instrument use to the Pittsburgh Sleep Quality Index, Stress Response Inventory, Korean version of the International Physical Activity Questionnaire Short Form and Sleep Hygiene Scale. Date were analyzed by frequency, t-test, ANOVA, Pearson's correlation and hierarchical multiple regression using SPSS/win18.0. The sleep quality index was 7.35 (range 0-21), stress response was 2.20 (range 1-5), physical activity was 3986MET-min/week, and sleep hygiene was 2.73 (range 1-6 points). There were significant differences in sleep quality according to shift work experience, health status and circadian rhythm type. Factors influencing sleep quality included shift work experience, sleep hygiene, stress response and physical activity, which together explained 40% of the total variance of sleep quality. Therefore, it is recommended that sleep hygiene education be implemented as a strategy to reduce stress response, and that shift work nurses engage in a moderate level of physical activity to improve their sleep quality.