• The Journal of the Korea Contents Association
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• v.6 no.11
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• pp.258-265
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• 2006

DEVS formalism is advantageous in modeling large-scale complex systems and it reveals good readability, because it can specify discrete event systems in a hierarchical manner. In contrast, it has drawback in that the simulation speed of DEVS models is comparably slow since it requires frequent message passing between the component models in run-time. This paper proposes a method, called model composition, for simulation speedup of DEVS models. The method is viewed as a compiled simulation technique which eliminates run-time interpretation of communication paths between component models. Experimental results show that the simulation speed of transformed DEVS models is about 18 times faster than original ones.

• Journal of Korean Academy of Nursing Administration
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• v.21 no.5
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• pp.530-541
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• 2015

Purpose: This study was designed to construct a structural equation model and identify the effects and relationships of self-efficacy, career plateau, job embeddedness, organizational commitment and intent to turnover for nurses. Also, an attempt was made to derive a hypothetical model from these factors and to verify whether the model has validity as a means of explaining and anticipating turnover intention of nurses. Methods: Data were collected from six randomly selected hospitals: a university hospital located in J city, Kyungnam and five general hospitals located in two cities (cities B and C), each having 400 to 720 beds. Also, 318 nurses were surveyed. Data were analyzed using SPSS 21.0 and AMOS 18.0 program. Results: Job embeddedness and organizational commitment were identified as the most likely paths to turn over intention. Also, organizational commitment had the highest direct effect on turnover intention followed by job embeddedness and then self-efficacy, but career plateau had an indirectly effected turnover intention. Conclusion: As turnover intention was found to be greatly affected by organizational commitment and job embeddedness, methods to improve organizational commitment and job embeddedness should be actively developed to reduce turnover intention among nurses.

• Bulletin of the Korean Chemical Society
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• v.31 no.6
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• pp.1665-1668
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• 2010

The spin exchange interactions of $(VO)_2(H_2O){O_3P-(CH_2)_3-PO_3}{\cdot}2H_2O$ were examined by spin dimer analysis based on extended Huckel tight binding method. The strongest spin exchange interaction occurs through the super-superexchange path $J_2$ and the second strongest spin exchange interaction occurs through the superexchange interaction path $J_1$. There are two strongly interacting spin exchange paths in $(VO)_2(H_2O){O_3P-(CH_2)_3-PO_3}{\cdot}2H_2O$. Therefore, magnetic susceptibility curve of $(VO)_2(H_2O){O_3P-(CH_2)_3-PO_3}{\cdot}2H_2O$ can be well reproduced by an alternating onedimensional antiferromagnetic chain model rather than an isolated spin dimer model.

• Journal of Power Electronics
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• v.16 no.3
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• pp.970-981
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• 2016

Leakage currents occur in pulse-width-modulated voltage source inverter (PWM-VSI)-fed permanent magnet synchronous motor (PMSM) drives for air-conditioners, which seriously affect system safety and operation performance. High accuracy modeling and prediction of leakage currents are key issues for the design and implementation of air-conditioning products. In this study, the generation mechanism of leakage currents is discussed. A systematic modeling approach of leakage currents is proposed, including the modeling of leakage current sources and leakage current paths. By using the proposed approach, the complete model of leakage currents in PWM-VSI-fed PMSM drives for air-conditioners has been developed based on the extraction of all parameters. A comparison between the simulated leakage currents based on the developed model and measured leakage currents in the outdoor unit of an air-conditioning product is conducted. The comparison verifies the effectiveness of the proposed modeling approach, and the developed model exhibits high accuracy within a wide frequency range.

• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.703-709
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• 2008

In the shipyard, line heating and triangle heating are two major processes for forming curved plates in various shapes. While there have been many studies on line heating, triangle heating has been rarely studied due to its complicated heating process with irregular multi-heating paths and highly concentrated heat input. As the triangle heating process is one of the most labor-consuming jobs in shipyards, it is essential to study the automation as well as improvement of triangle heating process in order to increase hull forming productivity. In this study, a pioneering attempt to simulate triangle heating was made. A circular disk-spring model was proposed for elasto-plastic analysis procedure of triangle heating and the inherent strain method was also used to analyze the deformation of plates. Simulation results were compared with those of experiments and showed good agreement. It is shown that the present approach including analysis model used in this study is effective to simulate the triangle heating for plate forming process in shipbuilding.

• Journal of the Korean Geotechnical Society
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• v.18 no.5
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• pp.237-249
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• 2002

Nonlinearity and anisotropy of soil should be considered for the exact prediction of deformation before the failure state. In this study, a new constitutive model is developed in which the nonlinearity of soil is formulated by Ramberg-Osgood equation and the soil anisotropy is implemented by the cross-anisotropic elasticity. Nonlinear anisotropic model and other models for comparison are used to analyze the simple boundary value problems and the circular footing problem. In the results, the anisotropic ratio of elastic modulus is a key value for the bulk modulus of soil, the coeffcient of earth pressure at rest, and the slope of effective stress paths. Furthermore, it is found that the nonlinearity of soil considering the in-situ stresses has the great influence on the magnitude of settlements.

• Research in Community and Public Health Nursing
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• v.18 no.4
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• pp.624-633
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• 2007

Purpose: The purpose of this study was to develop and test a structural model on work-related musculoskeletal disorders of women workers. Method: Data were collected from 237 women workers from industries such as electronics, food production and garment production, and analyzed by LISREL 8.54. Result: The fitness indices of the model are GFI=.87, NNFI=.91, PNFI= .74. Eight out of the ten paths were proved to be statistically significant: work environment$\rightarrow$social support, work environment$\rightarrow$health behavior, work environment$\rightarrow$-WMSDs, domestic work$\rightarrow$health behavior, social support$\rightarrow$health behavior, social support$\rightarrow$job satisfaction, health behavior$\rightarrow$job satisfaction, and job satisfaction$\rightarrow$WMSDs. Work environment. social support, health behavior and job satisfaction significantly influenced WRMDs. WRMDs were accounted for 35% by the predictor variables. Conclusion: In conclusion, this study identifies that work environment, social support, health behavior and job satisfaction are important factors affecting WMSDs. Therefore, in order to prevent WRMDs, it is most important to improve both physical work environment for female workers such as appropriate work station and tools fit for them and psychological environment such as less job demand and more decision latitude(worker control).

• Journal of Information Technology and Architecture
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• v.9 no.1
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• pp.79-93
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• 2012

This study is designed to define the competencies of EA experts. We investigated domestic and oversea curriculums and finally suggested basic and common competencies of EA experts. Especially, various EA stakeholder can commonly refer and use our competencies. Therefore those can be the foundation of continuous EA competencies development model. We define 4 EA core competencies such as common, development, analysis, management and provide definition of competencies. And we also classify the competencies importance of 3 career paths (Architect, Enterprise Architect, Chief Architect). The results of this research can help EA experts and IT personnel to understand EA and to enhance their competencies by providing standard competencies of teaching course and curriculum.

• Journal of Information Technology Services
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• v.6 no.1
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• pp.83-99
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• 2007

The purpose of this research is to identify the determinants of loyalty in online games. This study developed a research model to analyze the factors explaining the loyalty level from gamers, employing social identification, flow, and positive anticipated emotion as major research variables, and collected 1308 survey responses from gamers. Within the context of arguing that the exploration of age range issues with respect to online games is important, this research also examines the age differences in path coefficients. To this end, the structural model was tested with the data from entire data sample (i.e., the age of 10s, 20s, and 30s pooled together) and each of the subsamples (i.e., teens taken separately, twenties taken separately, and thirties taken separately). Properties of the causal paths, including standardized path coefficients, the significance of difference, in the hypothesized model, are also presented, so that we can investigate the relative influences of different dominants, demonstrating how teens, twenties, and thirties differ in their decision-making processes regarding the flow, social identification and loyalty from online games.

• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.212-212
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• 2015

So far, geomorphologic dispersion due to the heterogeneity characteristics of flow paths in a basin has been demonstrated as a major factor affecting to the hydrologic response function of a catchment. This effect has considered by many previous studies taking into account flow path length factors, especially in the application of width function. Based upon the analysis of topographic index, another important geomorphologic factor extracted from DEM data, this work presents a new factor named saturation to evaluate its effects to the formation of the well-known instantaneous unit hydrograph (IUH) in Nash model and drainage structure in a river basin. First, the geomorphologic parameters corresponding to different saturation conditions are computed from DEM data with the support of GIS software. Then, in the combination of hydrologic and geomorphologic data, effective rainfall in each saturation degree and the Nash parameters are calculated using excel. Finally, the verification process with direct runoff data is conducted using Fortran programming. This process is applied to five sub-watersheds in Bocheong catchment ($485.21km^2$) in Korea where the necessary data are available and believable. The results from this approach will improve researchers and students'understandings about the relationship between rainfall and runoff and its relation with drainage structure within a catchment.