• Earthquakes and Structures
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• v.20 no.4
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• pp.389-403
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• 2021

Skewed bridges, being irregular structures with complicated dynamic behavior, are more susceptible to earthquake damage. Reliable seismic-resistant design of skewed bridges can be achieved by accurate determination of nonlinear seismic demands. However, the effect of geometric characteristics on the response modification factor (R-factor) is not accounted for in bridge design practices. This study attempts to investigate the effects of changes in the number of spans, skew angle and bearing stiffness on R-factor values and to assess the seismic fragility of skewed bridges. Results indicated that changes in the skew angle had no significant effect on R-factor values which were in consonance with code-prescribed R values. Also, unlike the increase in the number of spans that resulted in a decrease in the R-factor, the increase in bearing stiffness led to higher R-factor values. Findings of the fragility analysis implied that although the increase in the number of spans, as well as the increase in the skew angle, led to a higher failure probability, greater values of bearing stiffness reduced the collapse probability. For practicing design engineers, it is recommended that maximum demands on substructure elements to be calculated when the excitation angle is applied along the principal axes of skewed bridges.

• Journal of the korean academy of Pediatric Dentistry
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• v.34 no.3
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• pp.438-446
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• 2007

Viable cells of periodontal ligament would be an important factor for the successful replantation of an avulsed tooth. Therefore, it is critical to choose the storage medium for the preservation of traumatically avulsed teeth. Growth factors and hormones could be considered for the therapeutic application of the maintenance of viable periodontal ligament fibroblasts (PDLFs). Epidermal growth factor (EGF) has been suggested as an important player for the regeneration and wound healing process on other tissues. Therefore, EGF was evaluated for the therapeutic application on avulsed teeth. In addition, the synergic effect of EGF with tri-iodothyronine (T3) and heparin-binding epidermal growth factor-like growth factor (HB-EGF). The cell proliferation of PDLFs was determined by MTT assay and increased dose-dependently up to 10 ng/ml in the presence of EGF. Maximum cellular growth was shown at the concentration of 10 ng/ml EGF. Also, EGF promoted the wound healing of PDLFs examined by in vitro wound healing assay. Combined effects of EGF with T3 or HB-EGF on the proliferation of PDLFs were also studied. Interestingly, EGF showed the synergic effect on the proliferation of PDLFs with T3 and HB-EGF. To find out the mechanism of the synergic effect of EGF and T3, the effect of T3 on the expression of endogenous EGF receptor was determined by RT-PCR. The result was that T3 enhanced the expression of EGF receptor in PDLFs. It suggested that EGF might be a good choice for a therapeutic application, which can be used as combination with T3 and HB-EGF.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.157-169
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• 2021

The purpose of this study was to investigate the satisfaction of personal media use based on individual psychological characteristics, that is, sensory propensity and media engagement effect. The results of verifying the research hypothesis are as follows. First, it was found that the 'Thrill and Adventure Seeking' factor and the 'Experience Seeking' factor had a significant influence on the use satisfaction of personal media with the characteristics of sensory orientation. It was found that the 'Disinhibition' factor had a positive effect on media engagement, and that media engagement had a positively significant effect on the satisfaction of personal media use. Finally, looking at the effect of the characteristics of sensation seeking on the satisfaction of personal media use through media engagement, the 'Thrill and Adventure Seeking' factor, the 'Experience Seeking' factor, and the 'Disinhibition' It was found to have a significant effect. It is expected that this study will be a useful basic material for establishing the direction and marketing strategy for personal media production.

• Structural Engineering and Mechanics
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• v.47 no.5
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• pp.643-660
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• 2013

In the present work, the capacity ratings of steel truss bridges have been carried out incorporating dynamic effect of moving vehicles and its accumulating effect as fatigue. Further, corrosion in the steel members has been taken into account to examine the rating factor. Dynamic effect has been considered in the rating procedure making use of impact factors obtained from simulation studies as well as from codal guidelines. A steel truss bridge has been considered to illustrate the approach. Two levels of capacity ratings- the upper load level capacity rating (called operating rating) and the lower load level capacity rating (called inventory rating) were found out using Load and Resistance Factor Design (LRFD) method and a proposal has been made which incorporates fatigue in the rating formula. Random nature of corrosion on the steel member has been taken into account in the rating by considering reduced member strength. Partial safety factor for each truss member has been obtained from the fatigue reliability index considering random variables on the fatigue parameters, traffic growth rate and accumulated number of stress cycle using appropriate probability density function. The bridge has been modeled using Finite Element software. Regressions of rating factor versus vehicle gross weight have been obtained. Results show that rating factor decreases when the impact factor other than those in the codal provisions are considered. The consideration of fatigue and member corrosion gives a lower value of rating factor compared to those when both the effects are ignored. In addition to this, the study reveals that rating factor decreases when the vehicle gross weight is increased.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.17 no.31
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• pp.33-42
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• 1994

This paper aims to analyse and appraise the effect of human performance to the variation of quality through constructing the dynamic recursive control model considering the human factor in a single production system. The model studied in this paper has a great advance from the point of combinating three technologies(quality control, automatic control theory, human engineering) and can also be expanded in several applications.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.1511-1516
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• 2007

Because Seaming process of MPJ (Mechanical Press Joining) has various design factors such as thickness, bending radius, seaming width, caulking press width and the dynamic factor such as multistage plastic working, elastic recovery, residual stress, the optimum conditions can't be easily determined. Using a design of experiment based on the FEM, which has several advantages such as less computing, high accuracy performance and usefulness, this study was performed investigating the interaction effect between the various design factor as well as the main effect of the each design factor during drum MPJ and proposed optimum condition using center composition method among response surface derived from regression equation of simulation-based DOE.

• Journal of Periodontal and Implant Science
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• v.24 no.3
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• pp.572-580
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• 1994

The purpose of the present study was to evaluate the effect of platelet - derived growth factor(PDGF) - BB and insulin - like growth factor(IGF) - 1, Centella Asiatica, and Zea Mays L. on the mitogenic activity of PDL cells from healthy and RPP patients. Combination of PDGF - BB and IGF - 1, Centella Asiatica, and Zea Mays L. were treated on PDL cells and the mitogenic effects were meaured by quantitative assay of methyl - $^3H$ - thymidine incorporation during DNA synthesis. Combination of PDGF - BB and IGF - 1 enhenced the mitogenic effects of both healthy and RPP PDL cells, however, the effect was less pronounced on RPP PDL cells. In cases of Centella Asiatica and Zea Mays L., no mitogenic effect on healthy PDL cells could be noticed.

• Journal of Advanced Marine Engineering and Technology
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• v.28 no.3
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• pp.451-456
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• 2004

This present experimental study has dealt with the heat transfer characteristics of plastic particle slurry which flows in a circular tube. This type of slurry is suggested for heat transfer enhancement effect cause by random and vortex effect of plastic particle dispersed in water. As a result, the thermal boundary layer becomes thin so the heat transfer coefficient on the tube wall more increase compare to pure water flow. This experimental test section was composed with stainless pipe which has the length of 2000mm, inner pipe diameter of 14mm and outer pipe diameter of 60mm. The most effective and important parameter of this experiment is plastic packing factor(PPF). The focuses of these results are pressure drop and heat transfer coefficient. As results, the friction factor of plastic particle slurry becomes higher at laminar flow region than pure water because of buoyancy effect of plastic particle but the local heat transfer coefficient becomes higher.

• Journal of the Korean Society of Clothing and Textiles
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• v.28 no.910
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• pp.1197-1207
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• 2004

The purpose of this study was to identify the impact of materialism on the attitude toward purchasing foreign luxury brands and the moderating effect of consumer ethnocentrism on this impact. Data were gathered by surveying university students living in Seoul metropolitan area using convenient sampling, and 325 questionnaires were used in the statistical analysis. In analysing data, confirmatory factor analysis and path analysis were conducted using structural equation modeling. Results showed that success factor of materialism gave rise to negative attitude toward purchasing foreign luxury brands while centrality factor of materialism spurred positive attitude. Consumer ethnocentrism also showed a significant effect as a moderator on the relationship between materialism and attitude: The relationship between materialism and attitude was stronger among subjects who had lower consumer ethnocentric tendencies than among subjects who had higher consumer ethnocentric tendencies.

• Culinary science and hospitality research
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• v.14 no.3
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• pp.31-44
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• 2008

The purpose of this research was to examine the construct known as job fit perceived by service employees in the foodservice industry. The model was tested using SPSS 12.0 and AMOS 4.0 based on the sample of 667 persons that showed a 95% usable response rate. The results of the empirical analysis showed as follows. First, in restaurants, the employees' job suitability factor brings about an indirect effect by organizational commitment and turnover intention. Second, employees' job satisfaction factor causes an indirect effect by organizational commitment. Third, employees' organizational commitment factor has relationships with turnover intention. That is, the higher organizational commitment, the lower turnover intention. By the same route analysis, job suitability has an effect on organizational commitment. Also, the research proved organizational immersion has an effect on turnover intention. In this respect, the research contributes to job performance of foodservice employees, emphasizing the necessity of educational programs for them.