• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.538-541
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• 2006

PSC(Prestressed Concrete) box girder bridges have been widely applied in Korea. A number of these bridges have been built by the segmental construction method in the longitudinal direction and(or) vertically along the cross-sectional depth with MSS(Moving Scaffolding System). An actual 2-span continuous PSC box girder bridge of Kyeongbu high speed railway was selected and instrumented with 96 vibrating wire embedded type strain gauges and 2 thermocouples. The long-term behavior of the bridge was monitored through two major points located at mid-span of the first span and at the internal support. Data collection started just after the casting of the first segment (U section). Concrete strain and temperature data were gathered regularly by a data logger (CR10) during 600 days under and after construction. According to this measurement, the parabolic longitudinal strain distribution in the top slab at mid-span is shown. And also, the same distribution at the interior support is shown. The compressive strains at the cantilever region are larger than at the web position and the internal part in the top slab. Strain difference largely happened during the early construction period.

• Fibers and Polymers
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• v.1 no.1
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• pp.37-44
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• 2000

A finite element method is employed fer a flow analysis of the melt spinning process of a non-circular fiber, a PET(polyethylene terephthalate) filament. The flow field is divided into two regions of die channel and spin-line. A two dimensional analysis is used for the flow within the die channel and a three dimensional analysis fur the flow along the spin-line. The Newtonian fluid is assumed for the PET melt and material properties are considered to be constant except for the viscosity. Effects of gravitation, air drag force, and surface tension are neglected. Although the spin-line length is 4.5 m only five millimeters from the spinneret are evaluated as the domain of the analysis. Isothermal and non-isothermal cases are studied fer the flow within the die channel. The relationship between the mass flow rate and the pressure gradient is presented for the two cases. Three dimensional flow along the spin-line is obtained by assuming isothermal conditions. It is shown that changes in velocity and cross-sectional shape occur mostly in the region of 1mm from the die exit.

• Journal of Korean Public Health Nursing
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• v.21 no.1
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• pp.95-101
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• 2007

Purpose: The purpose of this study was to determine the incidence of unintentional-injury and to identify factors related to the high incidence of unintentional-injury in the community in order to provide useful data for the development of prevention and intervention programs aimed at reducing unintentional-injury incidence. Methods: This study utilized data obtained from cross-sectional national surveys conducted for the 2001 National Health and Nutrition Survey targeting 37,769 individuals aged between 0 and 99 years old, which was performed using a face-to-face interview method. Demographic characteristics, unintentional-injury experience, types of injury, and attributes of health behavior were included in the study instruments. Results: About 1.3% of the subjects had experienced unintentional injury that required hospitalization at least once during the past year. Age older than 40 years, male gender, lower education, lower income, and blue collar workers were all significantly and positively associated with increased risk of unintentional-injury. Among the health behavior variables, sleeping less than 6 hours, drunk driving, and binge drinking were significantly associated with unintentional injury, while traffic accidents and falls/slips constituted 80% of all unintentional injuries. Conclusion: Public health efforts to reduce unintentional injuries should target high-risk populations such as males, those with low income and education levels, and binge drinkers.

• Journal of Korean Academy of Nursing Administration
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• v.14 no.3
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• pp.260-267
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• 2008

Purpose: The objective of this study was to identify relationships among the perception of quality assurance and national hospital evaluation program and nursing performance of hospital nurses. Method: The participants were 401 nurses who worked at the A medical center. The data were collected from 25 April to 9 May. 2008. The cross-sectional descriptive survey was done using a structured questionnaire. Result: The perception of the quality assurance correlated significantly with nursing performance. Also, the perception of national hospital program correlated significantly with nursing performance. However, the scores of perception of quality assurance & national evaluation program of hospital nurses is relatively low. Conclusions: These results means positive perception of quality assurance of nurses can produce good nursing performance. It suggests that nurses need more education and training for quality assurance. And the incentives will be needed to enhance the perception of quality assurance. Moreover, the detailed nursing performance indicators should be developed to measure the quality of nursing performance properly.

• Journal of Korean Academy of Nursing
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• v.27 no.3
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• pp.705-714
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• 1997

This study was conducted to test validity of related factors and characteristics of 98 Nursing Diagnosis identified in a previous study by the Korean Nurses Association. Data for this study was collected from 892 nurses in eight teaching hospitals located in Seoul using a cross sectional survey method. Each participating hospital was asked to produce at least 10 cases for every nursing diagnosis. There were 7,422 responses out of a possible 7,840. Out of the 7,422 responses 26 were discarded due to incompleteness. Data were analyzed using SAS. The result of the study shows that most of the related factors and characteristics for each of the 98 nursing diagnosis were ranked at more than 3.5 point out of 5 point Likert scale in terms of significance. Through this study the related factors and characteristics of the 98 nursing diagnosis identificance. Through this study the related factors and characteristics of the 98 nursing diagnosis identified through literature review were validated by experts in nursing diagnosis. These validated related factors and characteristics will be utilized for computerization of the nursing diagnosis process.

• Journal of Korean Academy of Nursing
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• v.37 no.1
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• pp.35-43
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• 2007

Purpose: This study was to explore the prevalence of alcohol experiences and to identify the expectancy on the effects of alcohol and alcohol knowledge in early adolescents. Method: The cross-sectional survey of 1854 students from seven middle schools in one district of Seoul was conducted by convenience sampling. Alcohol experience and early onset of alcohol use were measured by the Youth Risk Behavior Survey. Alcohol expectancy was measured by an Alcohol Effects Questionnaire. Result: Over sixty five percent of adolescents reported that they had previous drinking experiences. The participants with no alcohol drinking experience had a lower level of alcohol knowledge than those with experience(t=2.73, p=.007). In expectancy on effects of alcohol, girls had a more positive alcohol expectation than boys(t=-2.54, p=.011). Alcohol knowledge negatively correlated with alcohol expectancy(r=-.40 p=.000). In regression of alcohol expectancy, gender and alcohol knowledge were significant predictors explaining 17%. Conclusion: The results support that alcohol expectancy is an important link with early drinking experiences and alcohol knowledge, focusing on the importance of gender differences. Therefore, an alcohol prevention program in early adolescence is needed and should be focused on multidimensionality of the alcohol expectancy with developmental and psychosocial factors for early adolescents.

• Journal of the Korean Ceramic Society
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• v.42 no.7 s.278
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• pp.455-460
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• 2005

Deposition of TiN$_{x}$ film was conducted with a DC sputtering technique. The effect of the processing parameters such as substrate temperature, deposition time, working pressure, bias power, and volumetric flowing rate ratio of Ar to N$_{2}$ gas on the resistivity of TiN$_{x}$ film was systematically investigated. Three kinds of substrates, soda-lime glass, (100) Si wafer, and 111m thermally grown (111) SiO$_{2}$ wafer were used to explore the effect of substrate. The phase of TiN$_{x}$ film was analyzed by XRD peak pattern and deposition rate was determined by measuring the thickness of TiNx film through SEM cross-sectional view. Resistance was obtained by 4 point probe method as a function of processing parameters and types of substrates. Finally, optimum condition for synthesizing TiN$_{x}$ film having lowest resistivity was discussed.

• Research in Community and Public Health Nursing
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• v.19 no.4
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• pp.622-635
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• 2008

Purpose: The purpose of this study was to measure the level of job stress and health status and find out factors affecting the health status among circulation enterprise workers. Method: This study was a cross-sectional descriptive study. The subjects were 128 workers whose mean age was 33.2 years. Korean occupational stress questionnaire Short Form was used to measure job stress. Todai Heath Index that was made by Aoki in 1977 and translated by Kim(1997) was used to measure the health status. Results: The total job stress scores of men and woman fell in the lower 50% of Korean workers. Job autonomy and interpersonal conflicts as a subcategories fell in upper level 50% in both men and women and job insecurity fell in the upper level 50% in women. The mean score of health status was 51.47, indicating slightly higher frequency of complains of health symptoms. There was no significant correlation between total job stress and total health status. Finally, factors influencing the health status were organizational system and age. Conclusion: Based on the results of this study, it is necessary to develop comprehensive stress management programs including interventions of personal and organizational levels for promoting workers' health.

• International Journal of Ocean Engineering and Technology Speciallssue:Selected Papers
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• v.6 no.1
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• pp.60-68
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• 2003

This paper proposes an optimum design method of structural and control systems, using a 2-D truss structure as an example. The structure is subjected to initial static loads and disturbances. For the structure, a FEM model is formed. Using modal transformation, the equation of motion is transformed into modal coordinates, in order to decrease D.O.F. of the FEM model. To suppress the effect of the disturbances, the structure is controlled by an output feedback $H_{\infty}$ controller. The design variables of the combined optimal design of the control-structure systems are the cross sectional areas of truss members. The structural objective function is the structural weight. The control objective function is the $H_{\infty}$ norm, the performance index of control. The second structural objective function is the energy of the response related to the initial state, which is derived from the time integration of the quadratic form of the state in the closed-loop system. In a numerical example, simulations have been perform. Through the consideration of structural weight and $H_{\infty}$ norm, an advantage of the combined optimum design of structural and control systems is shown. Moreover, since the performance index of control is almost nearly optimiz, we can acquire better design of structural strength.

• International Journal of Fluid Machinery and Systems
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• v.5 no.2
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• pp.91-99
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• 2012

The Fighter aircraft transmission system consists of a light weight, High Speed Flexible Coupling (HSFC) known as Power Take-Off shaft (PTO) for connecting Engine gearbox (EGB) with Accessory Gear Box (AGB). The HSFC transmits the power through series of specially contoured metallic annular thin flexible plates whose planes are normal to the torque axis. The HSFC operates at high speed ranging from 10,000 to 18,000 rpm. The HSFC is also catered for accommodating larger lateral and axial misalignment resulting from differential thermal expansion of the aircraft engine and mounting arrangement. The contoured titanium alloy flexible plates are designed with a thin cross sectional profile to accommodate axial and parallel misalignment by the elastic material flexure. This paper investigates the effect of misalignment on the transmission characteristics of the HSFC couplings. A mathematical model for the HSFC coupling with misalignment has been developed for analyzing the torque transmission and force interaction characteristics. An extensive testing has been conducted for validating characteristics of the designed coupling under various misalignment conditions. With this the suitability of the model adapted for the design iteration of HSFC development is validated. This method will reduce the design iteration cycles of HSFC and can be extended for the similar development of flexible couplings.