• Journal of Korean Society of Transportation
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• v.21 no.1
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• pp.65-75
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• 2003

In these days, public transportation has become important because of serious traffic congestion. But. there are few researches in public transportation compared with researches in auto. Accordingly, the purpose of paper is development of transit assignment model, which considers features of public transportation, time table, transfer capacity of vehicle, common line, etc. The transit assignment model developed in this paper is composed of two parts. One part is search for optimum path, the other part is network loading. A Genetic algorithm has been developed in order to search for alternative shortest path set. After the shortest paths have been obtained in the genetic algorithm, Logit-base stochastic loading model has been used to obtain the assigned volumes.

• Asian Journal of Atmospheric Environment
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• v.2 no.1
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• pp.60-67
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• 2008

The spatial limitations of urban environments in general lead to invention and design of a wide range of underground transportation systems such as subways, underground roads and paths, etc. Among them, the application of subway systems in metropolitan cities is most commonly observed to ease those confronted difficulties on this purpose. It in turn leaves passengers and workers to be exposed to indoor air potentially polluted by various sources existing in this underground environment. Specifically when considering the IAQ in a subway station, there exist many IAQ-related parameters to be counted either as individual or as integrated exposures. In this study, a model system has been developed to manage the general IAQ in a subway station. Field survey and $CO_2$ measurements were initially conducted to analyze and understand the relationship between the indoor and outdoor air quality while considering the internal pollution sources such as passengers, subway trains, etc. The measurement data were then employed for the model development with other static information. For the model development, the algorithm of simple continuity was built and applied to model the subway IAQ concerned. In this paper, the recent updated draft version of model developed will be reported and demonstrated.

• Child Health Nursing Research
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• v.25 no.4
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• pp.477-486
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• 2019

Purpose: This study was conducted to investigate the factors affecting health promotion behaviors in late school-aged children by establishing a hypothetical model based on the planned behavior theory. Methods: From July 19 to August 31, 2017, 460 questionnaires were distributed to fifth and sixth graders at three elementary schools in Korea, of which 318 were ultimately analyzed. Results: All the fit indices were shown to be appropriate, indicating satisfactory fit. In the final model, six of the nine paths included in the hypothetical model were supported. Specifically, perceived behavioral control had the most influence on intention, followed by subjective norms, self-esteem, and health knowledge. Intentions were the most influential factor for health-promoting behaviors, followed by self-esteem and health knowledge. Subjective norms, perceived behavioral control, and self-esteem explained 57.6% of intention to engage in health promotion behaviors and 61.7% of variation in health promotion behaviors was explained by health knowledge, self-esteem and intention. Conclusion: The findings of this study provide support for a model that can be used to facilitate the practice of health promotion activities in children in the later years of school age.

• Journal of Korean Academy of Fundamentals of Nursing
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• v.25 no.4
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• pp.269-281
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• 2018

Purpose: The purpose of this study was to build a model to predict the fall prevention behavior of nurses in small and medium sized hospitals. Methods: Participants were 382 nurses from 13 hospitals who responded to the structured self-reported questionnaire. The research model was based on previous study of fall prevention, theory of planned behavior, and the health belief model. Results: The modified model generally showed higher levels than recommended level of model fit indices and acceptable explanation. Of 17 hypothetical paths, 14 were supported. Predicting variables explained 51.6% of fall prevention behavior. The fall prevention behavior of nurses showed a direct influence of fall prevention expectations, fall prevent threats, perceived behavioral control for fall prevention, and intention to prevent falls and an indirect of influence of patient safety culture, attitude toward fall prevention, and the subjective norm. Conclusion: Findings show a need to identify a range of barrier factors to increase the benefits of fall prevention behavior and enhance the perceived control of fall prevention so that nurses will be able to promote fall prevention behavior in hospitals. Also, it is critical to increase awareness of patient safety culture among nurses.

• Research in Community and Public Health Nursing
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• v.30 no.3
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• pp.345-356
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• 2019

Purpose: The purpose of this study is to construct and test a structural equation model of posttraumatic growth (PTG) of earthquake victims based on Tedeschi and Calhoun's model (2004). Methods: Data were collected from 195 earthquake victims living in K. City. The exogenous variables include distress perception, resilience, and social support, and the endogenous variables include intrusive rumination, deliberate rumination, and posttraumatic growth. For data analysis, descriptive statistics, factor analysis, and structural equation modeling were performed. Results: The modified model showed a good fitness to the data. Moreover, 6 of the 9 paths of the final model were statistically significant, which include PTG affected by deliberate rumination (${\beta}=.58$, p<.001), resilience (${\gamma}=.18$, p=.001), and distress perception (${\gamma}=.20$, p=.002). These predictors explain 51.8% of variance in posttraumatic growth. Conclusion: Based on the results of this study, it is necessary to develop and disseminate preventive intervention programs to increase the resilience of earthquake-prone communities. In addition, after exposure to a community-scale traumatic event such as earthquake, we should provide social supports to alleviate distress perception and transition from intrusive rumination to deliberate rumination so that we can seek new meaning from the earthquake and facilitate posttraumatic growth.

• Journal of Korean Academy of Nursing
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• v.49 no.3
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• pp.241-253
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• 2019

Purpose: This study aimed to develop and test a model of the happiness of mothers with young children based on the stress-coping-adaptation model of Lazarus and Folkman. Methods: The data collection period was from May to July 2016. A self-report questionnaire was used to collect data from 210 mothers with children under 5 years of age living in Seoul, Gyeonggi, and Gangwon provinces. The exogenous variable was parenting stress, and the endogenous variables were parenting alliance, depression, optimism, ways of coping, and happiness. Data from 201 questionnaires were analyzed using the SPSS 22.0 and AMOS 20.0 programs. Data analyses included descriptive statistics, factor analysis, and structural equation modeling. Results: The final modified model showed a reasonable fit to the data, and out of 25 paths, 13 were statistically significant. This model explained 78.4% of the variance in the happiness of mothers with young children and confirmed that depression, optimism, parenting alliance, and social support-focused coping have a direct effect on the subject's happiness. Parenting stress also influenced happiness through parenting alliance, depression, and optimism. Conclusion: In order to bolster the happiness of mothers with young children, positive psychological interventions that can minimize psychological vulnerabilities, such as depression, and that can enhance their strengths, such as optimism, may serve as effective ways of coping with and adapting to stress.

• Nuclear Engineering and Technology
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• v.26 no.4
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• pp.562-569
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• 1994

In this study improvement of transient analysis model, KOTRAC, for the passive reactor has been performed. In the KOTRAC, mixture drift flux model is adopted to simulate thermal hydraulic behavior, which can simulate ECCS injection in the passive plant. However, there is a difficulty to handle complete phase separation phenomena due to the near-zero density, which may occur in the pressurizer surge line or horizontal flow paths. In this study, a couple of model changes to over-come Courant limit feilure has been examined. One of key features is to substitute flow distribution parameters with Ishii's correlation. Corrected results are nil compared to those of RELAP/MOD3 analysis.

• Journal of Communications and Networks
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• v.5 no.4
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• pp.303-308
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• 2003

We present a statistical model for the path loss of ultrawideband (UWB) channels in indoor environments. In contrast to our previously reported measurements, the data reported here are for a bandwidth of 6GHz rather than 1.25GHz; they encompass commercial buildings in addition to single-family homes (20 of each); and local spatial averaging is included. As before, the center frequency is 5.0GHz. Separate models are given for commercial and residential environments and, within each category, for lineof sight (LOS) and non-line-of-sight (NLS) paths. All four models have the same mathematical structure, differing only in their numerical parameters. The two new models (LOS and NLS) for residences closely match those derived from the previous measurements, thus affirming the stability of our path loss modeling. We find, also, that the path loss statistics for the two categories of buildings are quite similar.

• Nutrition Research and Practice
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• v.4 no.6
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• pp.528-534
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• 2010

This study explores the influence of health behaviors and individual attributes on adolescent overweight and obesity using data from Wave II (Add Health). Structural equation model/ path analysis using maximum likelihood estimation was utilized to analyze the relationships of health behaviors and attributes with obesity. Results of the model reveal that the causal paths (adolescents' attributes and health behaviors) for overweight and obesity were different for African American and Caucasian adolescents. Generally, African Americans were more susceptible to overweight and obesity than Caucasians. Although increasing levels of vigorous physical activities lowers the risk for obesity among African American and Caucasian adolescents alike, low family SES and being sedentary were associated with overweight and obesity among Caucasians. No significant associations were found among African Americans. Increased hours of sleep at night relate positively with obesity among African Americans. These findings suggest important elements in the consideration of race in developing effective intervention and prevention approaches for curbing the obesity epidemic among U.S. adolescents.

• Transactions of the Korean Society of Automotive Engineers
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• v.5 no.4
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• pp.84-92
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• 1997

Among the various sources of vehicle interior noise, this paper concerns the road induced noise ; the identification of its transfer path by using experimental method. Multiple input and single output model is taken as a noise generation model. Because it is impossible to measure the road imput forces directly, the acceleration signals are measured on four axle;three directions for each point. By considering the cross correlations of input signals, four uncorrelated source groups are taken. Multiple coherence function is employed to investigate the contribution of each group. In addtion, to identify the detailed path through the suspension systems, the contributions of all possible paths are ranked by using the coherence functions between interior noise and the relative accelerations of connections such as bushings and mountings. Measurements are performed with passenger vehicle traveling on concrete and asphalt roads at 60㎞/h.