• Journal of Preventive Medicine and Public Health
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• v.46 no.6
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• pp.329-335
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• 2013

Objectives: To comprehensively examine the relationship between current sleep duration and past suicidal idea or attempt among Korean adolescents. Methods: Data came from the 2009 Korea Youth Risk Behavior Web-based Survey with 75 066 participants (with the participation rate of 97.6%) in 800 middle and high schools. Binary logistic regression was conducted by gender and depressed mood to identify significant factors for suicidal ideation/attempt. The dependent variable was the log odds of suicidal ideation/attempt, while the independent/control variables were sleep duration and other demographic, socio-economic and health-related factors. Results: A negative association between sleep duration and suicidal ideation or attempt was weaker for those with depressed mood than for those without such experience in Korea for Year 2009. The odds ratio of suicidal ideation/attempt regarding less than 4 hours of sleep compared to 6 to 7 hours of sleep, was smaller in a group with depressed mood than in a group without such experience, for example, 1.64 (95% confidence interval [CI], 1.29 to 2.08) vs. 2.06 (95% CI, 1.34 to 3.17) for men's suicidal ideation, 2.50 (95% CI, 1.69 to 3.69) vs. 3.89 (95% CI, 1.74 to 8.66) for men's suicidal attempt. A negative association between age (or self-rated health) and suicidal ideation/attempt was also weaker for those with depressed mood than for those without such experience in the nation for the year. Conclusions: There was a negative association between sleep duration and suicidal ideation/attempt in Korea for Year 2009 and this association was weaker for those with depressed mood than for those without such experience. Based on the findings of this study, adolescents' better mental health and longer, more comfortable sleep might help to prevent their suicidal ideation and attempt in Korea.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.711-714
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• 2008

The objective of this study is to analyze the relationship between the watershed characteristics and the critical duration of design rainfall. For estimation of critical duration, adjustment Huff's method and ILLUDAS urban runoff model were applied to urban 21 areas. Watershed characteristics such as area, channel length, channel slope, shape factor, and pipe density were used to simulate correlation analysis. The conclusions of this study are as follows; it is revealed that critical duration is influenced by the watershed characteristics such as pipe density, area and channel length. Also, multiple regression analysis using watershed characteristics is carried out and the determination coefficient of multiple regression equation shows 0.972.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.44 no.2
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• pp.149-153
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• 1999

Prediction of rice developmental stage is necessary for proper crop management and a prerequisite for growth simulation as well. The objectives of the present study were to find out the relationship between the plastochrone index(PI) and the developmental index(DVI) estimated by non-parametric phenology model which simulates the duration from seedling emergence(DVI=0) to heading(DVI=l) by employing daily mean air temperature and daylength as predictor variables, and to confirm the correspondency of developmental indice to panicle developmental stages based on this relationship. Four japonica rice cultivars, Kwanakbyeo, Sangpungbyeo, Dongjinbyeo, and Palgumbyeo which range from very early to very late in maturity, were grown by sowing directly in dry paddy field five times at an interval of two weeks. Data for seedling emergence, leaf appearance, differentiation stage of primary rachis branch and heading were collected. The non-parametric phenology model predicted well the duration from seedling emergence to heading with errors of less than three days in all sowings and cultivars. PI was calculated for every leaf appearance and related to the developmental index estimated for corresponding PI. The stepwise polynomial analysis produced highly significant square-rooted cubic or biquadratic equations depending on cultivars, and highly significant square-rooted biquadratic equation for pooled data across cultivars without any considerable reduction in accuracy compared to that for each cultivar. To confirm the applicability of this equation in predicting the panicle developmental stage, DVI at differentiation stage of primary rachis branch primordium was calculated by substituting PI with 82 corresponding to this stage, and the duration reaching this DVI from seedling emergence was estimated. The estimated duration revealed a good agreement with that observed in all sowings and cultivars. The deviations between the estimated and the observed were not greater than three days, and significant difference in accuracy was not found for predicting this developmental stage between those equations derived for each cultivar and for pooled data across all cultivars tested.

• Earthquakes and Structures
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• v.3 no.1
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• pp.1-15
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• 2012

An empirical predictive relationship correlating bracketed duration to earthquake magnitude, site-to-source distance, and local site conditions (i.e. rock vs. stiff soil) for stable continental regions of North America is presented herein. The correlation was developed from data from 620 horizontal motions for central and eastern North America (CENA), consisting of 28 recorded motions and 592 scaled motions. The bracketed duration data was comprised of nonzero and zero durations. The non-linear mixed-effects regression technique was used to fit a predictive model to the nonzero duration data. To account for the zero duration data, logistic regression was conducted to model the probability of zero duration occurrences. Then, the probability models were applied as weighting functions to the NLME regression results. Comparing the bracketed durations for CENA motions with those from active shallow crustal regions (e.g. western North America: WNA), the motions in CENA have longer bracketed durations than those in the WNA. Especially for larger magnitudes at far distances, the bracketed durations in CENA tend to be significantly longer than those in WNA.

• Culinary science and hospitality research
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• v.16 no.3
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• pp.174-187
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• 2010

The purpose of this study was to examine the effect of franchisor's training on franchisee's trust and relationship satisfaction. In addition, it investigated the difference in the perception of franchisor's training system by the duration of the franchise contract and the frequency of franchisor's visiting. In order to carry out the empirical study, a questionnaire was distributed to franchisees from July 26 to September 1, 2009, and a total of 255 copies were returned and used for analysis. In analyzing the data, three factors of the franchisor's training were obtained: pre-training, franchisor training, and supervisor training. These three factors had a significant effect on franchisee's trust and satisfaction with the relationship. Also, There was significant differences among franchisor's training by duration of the franchise contract. The findings of the study suggested useful implications in the related industries.

• The Journal of the Korea Contents Association
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• v.11 no.4
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• pp.347-360
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• 2011

This paper is to identifies relationship between service quality, trust toward employees, trust toward store and store loyalty by investigate how service quality influences on trust toward employees and trust toward store, and its, in turn, influence on store loyalty and explain the moderating effect in relationships between service quality and trust toward employees, and service qualty and trust toward store in bank services setting. A survey study was conducted to collect the data with the actual service purchasers at domestic mayor banks. Analysis of structural equation modeling with AMOS 18.0 was performed to test the research hypothesis. The results of the study are as follows: First, it was found to the moderating effect in relationships between empathy dimension of service quality and trust toward employees, and assurance dimension of service quality and trust toward store. Second, service quality shows differential effects on both trust toward employees and trust toward store by dimension but trust toward employees influence on both trust toward store and it, in turn, influence on store loyalty. To sum up, it have to build empathy of service quality for increase of trust toward their customer who have high duration of relationship and have to build assurance of service quality for increase of trust toward store in bank service settings.

• Journal of Communications and Networks
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• v.17 no.6
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• pp.558-567
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• 2015

In recent years, we have seen a proliferation of mobile-network-enabled smart objects, such as smart-phones and smart-watches, that form a cyber-physical integrated network to connect the cyber and physical worlds through the capabilities of sensing, communicating, and computing. Discovery of the relationship between smart objects is a critical and nontrivial task in cyber-physical integrated network applications. Aiming to find the most stable relationship in the heterogeneous and dynamic cyber-physical network, we propose a distributed and efficient relationship-discovery algorithm, called dynamically maximizing remaining unchanged time with minimum connected dominant set (DMRUT-MCDS) for constructing a backbone with the smallest scale infrastructure. In our proposed algorithm, the impact of the duration of the relationship is considered in order to balance the size and sustain time of the infrastructure. The performance of our algorithm is studied through extensive simulations and the results show that DMRUT-MCDS performs well in different distribution networks.

• Journal of Korean Academy of Nursing Administration
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• v.5 no.1
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• pp.169-180
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• 1999

The purpose of this study was to identify the degree of stress and job satisfaction and the relationship of stress and job satisfaction of oriental hospital nurses. The subjects were 255 nurses of 9 oriental hospital in Taegu and Pusan cities and data were collected from 20 March to 10 May 1998. The instruments used for this study were a survey of genernal characteristics(7 items). stress(6 items) and job satisfaction(20 items). Analysis of data was done by use of mean, percentage, t-test, ANOVA and pearson correlation with SPSS program. The results of this study are as follows : 1) The average item score for stress was 3.08. Religion, duration of nurse expectancy and work motivation among sociodemographic characteristics were significantly different with the degree of stress. 2) The average item score for job satisfaction was 2.84. Education, religion, marital state, carrier history, duration of nurse expectancy and work motivation among sociodemographic characteristics were significantly different with the degree of job satisfaction. 3) There were significant negative correlation among the variables : working volume and group conflict factors · role implementation fators${\cdot}$personal socialization fators/nursing skill and role implementation fatal's· personal socialization fators/rolesharing with peers and role implementation fators/relationship with co-workers and group conflict factors${\cdot}$role implementation fators${\cdot}$personal socialization fators/relationship with patients and role implementation fators/relationship with supervisors and role implementation fators. And there was a significant positive correlation between role-sharing with peers and decision-making fators.

• Journal of Korean Academy of Nursing Administration
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• v.7 no.1
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• pp.165-172
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• 2001

The purpose of this study was to determine the relationship between self-efficacy and adherence of exercise in patients with ankylosing spondylitis. The subjects for this study were the 50 patients with ankylosing spondylitis who had been diagnosed as out patients in the Rheumatism Center of one university hospital in Seoul and participated in the 8 weeks exercise program. The data were collected by a questionnaire the period from April 1 to May 2, 2000. Data were analyzed by t-test, ANOVA, Pearson's correlation coefficient, Frequencies, using the SAS program. The results were as follows: The mean duration for exercise adherence of ankylosing spondylitis was 12.2 months. The mean self-efficacy score was 74.3 in a possible range of 10 to 100. A significant difference of self-efficacy was found between adherers and non-adherers and self-efficacy of adherer was higher than that of non-adheres(t=4.25, p=.001). Self-efficacy was significantly associated with the total duration of an exercise adherence(r=.42, p=.001). These findings may indicate that the relationship between self-efficacy and exercise adherence in patients with ankylosing spondylitis was supported. From these results, it can be suggested that the relationship between self-efficacy and exercise adherence in patients with ankylosing spondylitis. Therefore, intervention is needed to promote self-efficacy of ankylosing spondylitis and futher studies should develop self-efficacy promoting programs for patients with ankylosing spondylitis.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.52 no.1
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• pp.112-121
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• 2007

Grain filling is a crucial factor that determines grain yield in crops since it is the final process directly associated with crops' yield performance. Grain filling process can be characterized by the interaction of rate and duration of grain filling. This study was conducted, using 16 temperate japonica rice genotypes, with aims to (1) seek variations in grain filling duration and rate on area basis, (2) compare the contribution of grain filling duration and rate to grain yield, and (3) examine the influence of temperature and solar radiation for effective grain filling on grain yield in relation to grain filling duration and rate. Grain filling rate and duration exhibited highly significant variations in the ranges of $20.7{\sim}46.3\;g\;m^{-2}d^{-1}\;and\;11.2{\sim}35.5$ days, respectively, depending on rice genotypes. Grain yield on unit area basis was associated positively with grain filling duration but negatively with grain filling rate. Grain filling rate and duration were negatively correlated with each other. Final grain weight increased linearly with the rise in both cumulative mean temperature and cumulative solar radiation for effective grain filling. Higher cumulative mean temperature and cumulative solar radiation for effective grain filling were the results of longer grain filling duration, but not necessarily higher daily mean temperature and daily solar radiation for effective grain filling. Grain filling rate demonstrated an increasing tendency with the rise in daily mean temperature for effective grain filling but their relationship was not obviously clear. It was concluded that grain filling duration, which influenced cumulative mean temperature and cumulative solar radiation for effective grain filling, was the main factor that determined grain yield on unit area basis in temperate Japonica rice.