• Journal of Mechanical Science and Technology
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• 제16권6호
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• pp.819-828
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• 2002

An analytical method is presented for evaluation of the steady state periodic behavior of nonlinear systems. This method is based on the substructure synthesis formulation and a MS (multiple scales) procedure, which is applied to the analysis of nonlinear responses. The proposed procedure reduces the size of large degrees-of-freedom problem in solving nonlinear equations. Feasibility and advantages of the proposed method are illustrated with the nonlinear rotating machine system as an example of large mechanical structure systems. In addition, its efficiency for nonlinear response prediction will be shown by comparison of other conventional methods.

• Journal of Korean Biological Nursing Science
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• 제24권4호
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• pp.209-218
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• 2022

Purpose: This study aimed to investigate the relationships between the characteristics of nurses' work schedules, health outcomes, and work-life balance. Methods: This was a secondary data analysis that included 422 nurses in Korean hospitals. Descriptive analysis, independent sample t-test, one-way ANOVA, Pearson correlation analysis, and multiple linear regression analysis were used to identify the associated factors. Results: Multiple linear regression analysis showed that work-life balance was lower when atypical work was performed (β=-.14, p=.010). Nurses who did not work overtime showed a higher level of work-life balance than those who worked overtime infrequently (β=-.11, p=.002) or frequently (β=-.28, p<.001). The work-life balance level increased when nurses had better subjective health status (β=.16, p<.001) or higher sleep quality (β=.29, p<.001). It was verified that the work-life balance level was higher for single-person households than for households with two (β=-.18, p=.003), three to four (β=-.16, p=.022), or five or more (β=-.21, p<.001) persons. Conclusion: This study suggests that government and hospital organizations should provide high-quality care and consideration to nurses who do atypical or overtime work as well as their subjective health status and sleep quality. Further research should focus on the development of a policy that improves the work-life balance of nurses, especially for those who work during atypical hours.

• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.308-313
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• 2015

This paper describes a technique for complete identification of a two-dimensional scattering object and multiple objects immersed in air using microwaves where the scatterers are assumed to be a homogenous dielectric medium. The employed technique consists of initially retrieving the shape and position of the scattering object using a linear sampling method and then determining the electric permittivity and conductivity of the scatterer using adjoint sensitivity analysis. Incident waves are assumed to be TM (Transverse Magnetic) plane waves. This inversion algorithm results in high computational speed and efficiency, and it can be generalized for any scatterer structure. Also, this method is robust with respect to noise. The numerical results clearly show that this hybrid approach provides accurate reconstructions of various objects.

• Structural Engineering and Mechanics
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• 제76권5호
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• pp.631-641
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• 2020

In the present work, an approach for the multiple time probabilistic characterization of the response of linear structural systems subjected to random non-Gaussian processes is presented. Its fundamental property is working directly on the multiple time probability density functions of the actions and of the response. This avoids of passing through the evaluation of the response statistical moments at multiple time or correlations, reducing the computational effort in a consistent measure. This approach is the extension to the multiple time case of a previously published dynamic Probability Transformation Method (PTM) working on a single evolution of the response statistics. The application to some simple examples has revealed the efficiency of the method, both in terms of computational effort and in terms of accuracy.

• 한국지진공학회논문집
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• 제3권2호
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• pp.77-86
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• 1999

이전의 연구에서 하중증분법을 이용하여 지점 변위를 일으키고 자중. 부력, 그리고 조류력을 받는 해양케이블의 초기평형 상태를 결정하였다 본 연구에서는 이 상태를 기준으로 동적으로 지점운동 또는 지진하중에 대하여 첨가질량 및 케이블운동에 의한 Morison force를 고려한 해양케이블의 동적 비선형해석을 수행한다 지점운동과 지진력을 받는 수중케이블에 대하여 기하학적인 비선형해석을 수행하고 해석결과의 분석을 통하여 해양케이블의 동특성을 파악한다.

• 한국응급구조학회지
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• 제20권1호
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• pp.17-30
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• 2016

Purpose: This study investigated factors related to empowerment of paramedic students. Methods: A total of 208 students in the department of emergency medical services who experienced clinical practice at 5 universities were selected by convenience sampling methods. Differences in empowerment by general and major-related characteristics were evaluated using a t-test and analysis of variance. The association between satisfaction with clinical practice and empowerment was tested using correlation coefficients. Multiple linear regression analysis was performed to investigate the factors associated with empowerment. Results: The levels of overall satisfaction with clinical practice and empowerment were 107.48 and 99.46, respectively. In simple analysis, empowerment level was associated with general characteristics, major-related characteristics, characteristics of clinical practice, and satisfaction with clinical practice. Empowerment level was significantly higher in older subjects (${\beta}=5.282$, p = .023), subjects with very good (${\beta}=8.487$, p = .002) or fair (${\beta}=4.879$, p = .010) subjective health status, and high subjective school record (${\beta}=5.837$, p = .008) in multiple linear regression analysis. Satisfaction with clinical practice was positively associated with empowerment (${\beta}=0.250$, p < .001). Conclusion: Empowerment was associated with major-related factors and satisfaction with clinical practice. Increased satisfaction with clinical practice could positively influence empowerment for paramedic students.

• 한국학교ㆍ지역보건교육학회지
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• 제15권2호
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• pp.51-61
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• 2014

Objectives: This study examined the factors affecting the quality of life relating to oral health using OHIP-14 of college students. Also, this was to help college students to enhance their oral health. Methods: A Total of 334 self-administered questionnaires were collected from university student in Cheon-an. The statistical methods used for data analysis were the descriptive statistics, Independent samples t-test, One-way ANOVA, correlation analysis, multiple linear regression analysis. Results: First, A month pocket money and coffee consumption were significantly related to functional and physical Oral health foctor. Second, A month pocket money and coffee consumption were significantly related to Mental and social Oral health foctor. Finally, multiple linear regression analysis showed that a month pocket money, coffee consumption have a negative effect on the quality of life relating to oral health, Whereas an experience of oral health education a positive effect on this. Conclusion: Oral health related quality of life should be improved by investigating the factors affecting oral health and thus developing the program enhancing the oral health to prevent oral disease. In addition, in order to health promotion physical, mental, social, including the oral health, program development and research incessant must be carried out.

• 한국분무공학회지
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• 제20권4호
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• pp.247-253
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• 2015

Recently, the engine calibration technique has been much more complicated than that of the past engine case in order to satisfy the strict emission regulations. The current calibration method for the diesel engine which has an increasing market is both costly and time-consuming. New engine calibration method is required to develop for high-quality diesel engines with low cost and release it at the appropriate time. This study provides the optimal calibrating technique for complex engine systems using statistical modeling and numerical optimization. Firstly, it design a test plan based on Design of Experiments, a V-optimality methodology which is suitable looking for set-points, and determine the shape of test engine response. Secondly, it uses functions to make linear regression model for data analysis and optimization to fit the models of engines behavior. Finally, it generates the optimal calibrations obtained directly from empirical engine models using Grey Relational Analysis and compares the calibrations with data. This method can develop a process for systematically identifying the optimal balance of engine emissions.

• Membrane and Water Treatment
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• 제13권5호
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• pp.219-225
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• 2022

5th Assessment Report of the Intergovernmental Panel on Climate Change Weather (AR5) predicts that recent severe hydrological events will affect the quality of water and increase water pollution. To analyze changes in water quality due to future climate change, input data (precipitation, average temperature, relative humidity, average wind speed, and solar radiation) were compiled into a representative concentration curve (RC), defined using 8.5. AR5 and future use are calculated based on land use. Semi-distributed emission model Calculate emissions for each target period. Meteorological factors affecting water quality (precipitation, temperature, and flow) were input into a multiple linear regression (MLR) model and an artificial neural network (ANN) to analyze the data. Extensive experimental studies of flow properties have been carried out. In addition, an Acoustic Doppler Velocity (ADV) device was used to monitor the flow of a large open channel connection in a wastewater treatment plant in Ho Chi Minh City. Observations were made along different streams at different locations and at different depths. Analysis of measurement data shows average speed profile, aspect ratio, vertical position Measure, and ratio the vertical to bottom distance for maximum speed and water depth. This result indicates that the transport effect of the compound was considered when preparing the hazard analysis.

• Current Research on Agriculture and Life Sciences
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• 제24권
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• pp.49-53
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• 2006

The objective of this study was to present regression equations between reservoir water quality and land use types of the watersheds. In order to derive regression equations, a multiple linear regression analysis was used using observed data from 88 reservoirs in the Kyungpook Provcince. The measured values of BOD, COD, T-N, and T-P were correlated with the areas of land use types. 23 regression equations were obtained for all the water quality items and watershed sizes. The results showed that 2 regression equations have the multiple correlation coefficient(MCC) above 0.90, 10 regression equations have the MCC values from 0.70 to 0.90, 9 equations have the MCC from 0.40 to 0.70, and 2 equations have the MCC from 0.20 to 0.40. The results of this study can be used to estimate reservoir water quality simply and quickly in the planning phase.