• Wind and Structures
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• v.7 no.3
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• pp.145-158
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• 2004

The evaluation of the accumulation of permanent set for inelastic structures due to wind action is important in establishing a criterion to select a reduced design wind load and in incorporating the beneficial ductile behaviour in wind engineering. A parametric study of the accumulation of the permanent set as well as the ductility demand for bilinear single-degree-of-freedom (SDOF) systems is presented in the present study. The dynamic analysis of the inelastic SDOF system is carried out using the method of Newmark for artificially generated time history of wind speed. Simulation results indicate that the mean of the normalized damage rate is highly dependent on the natural frequency of vibration. This mean value is relatively insensitive to the damping ratio if the damping ratio is larger than 5%. The scatter associated with the accumulation of the permanent set is very significant. The consideration of the postyield stiffness can significantly reduce the accumulation of the permanent set if the ratio of the yield strength to the expected peak response is small. The results also show that the ductility demand due to the wind action over a period of one hour for flexible structures can be much less than that for rigid structures or structures with larger damping ratio if the SDOF systems are designed with a reduced peak response caused by the fluctuating wind.

• Journal of Families and Better Life
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• v.11 no.1
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• pp.22-34
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• 1993

The purposes of this study are as follows: 1) To estimate the amounts of differences in service expenditures resulting from the effects of mother's marital and employment status. 2) To find out the relationship of socio-economic variables to expenditures for time-saving durables and services Data were taken from the 1988-1989 Consumer Expenditure Survey. The sample consisted of 2,216 families with 334 single-mother families and 1,792 married-mother families. Tobit regres-sion analyses were used to test of variables related to expenditures for (a) food away from home. (b) clothing care (c) child care (d) domestic services and (e) total services. The results of this study were as follows; 1) The percentage difference from non-employed married-mother families was higher for employed single-mother families than for other types of families indicating the positive effect on expenditures on market substitutes of mother's marital and employment status. 2) The father's wage rate was associated only with expenditures for domestic services. A positive relationship was found between family nonlabor income and domestic services Total family income was positively associated with expenditues for all dependent variables. There was a negative relationship between expenditures for child care and age of mother squared. Mother's education was associated with expenditures in all categories. Families of nonwhite spent less on time-saving durables. food away from home, and total services and spent more on apparel services than families of white mothers. The presence of young child was positively related to total services and child care services and negatively related to food away from home.

• Proceedings of the Korea Concrete Institute Conference
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• 1999.04a
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• pp.269-274
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• 1999

Various method have been developed for mass concrete structures to reduce the temperature increase of concrete mass due to exothermic hydration reactions of concrete compounds and thereby to avoid thermal cracks. One of the methods widely acceptable for practical use is pipe cooling, in which cooling is achieved by circulating cold water through thin-wall steel pipes embedded in the concrete. A numerical simulation was performed to investigate the effectiveness of pipe cooling. A three-dimensional finite element method was proposed to analyse the transient three-dimensional heat transfer between the hardening concrete and the cooling water in pipe and to predict the stress development during the curing process. The effects of the cement type and content and the environment were taken into consideration by the heat generation rate and the boundary conditions, respectively. In order to test the validity of the numerical simulation, a model RC structure with pipe cooling was constructed and the time-dependent temperature and stress distributions within the structure as well as the variation of the temperature of cooling water along the pipe were measured. The results of the simulation agreed well the experimental measurements. The results of this study have important implications for the optimal design of the cooling pipe layout and for the estimation of thermal stress in order to eliminate thermal cracks.

• International Journal of Human Ecology
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• v.8 no.1
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• pp.79-94
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• 2007

Previous studies showed that traditional attitudes toward consumer credit and the accumulation of debtare declining, especially among younger life stage groups. The social stigma of high debt levels has largely gone. However, only a few researchers have studied and changes in consumers' attitudes toward credit and its determinants. This study investigates factors related to the probability of respondents having favorable or unfavorable attitudes using the 1992-2004 U.S. Surveys of Consumer Finances. A logistic analysis was used since the dependent variables were binary. All other things equal, respondents in 1995, 1998, 2001 and 2004 were significantly less likely to have favorable or unfavorable attitudes toward credit than otherwise similar respondents in 1992, but the patterns did not correspond well to the changes in the bankruptcy rate. Black and Hispanic respondents were more likely to have favorable attitudes and less likely to have unfavorable attitudes than were otherwise similar white respondents, but those in the Other group, mostly Asians, were not significantly different from whites. Respondents with college degrees were less likely to have a positive attitude and more likely to have a negative attitude than those without a college degree. Respondents who took risks with investments were more likely to have a positive attitude and less likely to have a negative attitude than those unwilling to take risks. Implications for understanding of credit use are discussed. This publication was made possible by a generous grant from the NASD Investor Education Foundation.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.320-323
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• 2008

In this paper, electro-optical characteristic of Nematic Liquid crystal (LC) with varying temperature in different LCD modes, namely Fringe Field Switching (FFS), In-plane switching (IPS), and Patterned Vertical Alignment (PVA) modes are investigated and compared. Electro optic me asurements suggest that rate of change of transmission with temperature in FFS mode was lowest and much more thermally stable as compared to IPS and PVA m odes. However the electro-optical characteristic of patterned vertical alignment (PVA) mode was most affected by changing temperature. The measured threshold voltage was found to be much more thermally stable in FFS and IPS modes than that of PVA mode.

• Journal of Information Technology Applications and Management
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• v.15 no.3
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• pp.127-152
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• 2008

This study sought to explore how SMEs are utilizing EC. Drawing on existing research on IT and EC related field, this study presented the framework of EC utilization level and analyzed its affecting factors in the point of organizational perspectives; strategy and competency. The impact of EC utilization on firm performance was also examined by employing BSC. Structural equation model was applied to test the relationships among the theoretical constructs with data from 171 SMEs. The results showed that the rate of EC utilization in SMEs is growing quite rapidly. However, manufacturing related firms still remain at a lower level compared to service related firms. As for the two affecting factors of EC utilization level, it was found that the level of EC utilization appeared to be driven not by strategy but by competency. This result implicates that EC utilization in SMEs doesn't reach to strategic purpose yet, while it is dependent on firm's competency. As far as the impact of EC utilization on firm performance, the study showed that the level of EC utilization has significant relationship with all perspectives performance indicators of BSC. This study can provide the managers with current EC utilization pattern and the guidelines as to where to put the efforts in the EC utilization and how to get an effective EC utilization strategy in the future.

• The korean journal of orthodontics
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• v.23 no.4 s.43
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• pp.493-501
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• 1993

It is the aim of this study to determine the impacts of radicular development of lower third molars on its eruption/impaction and to grope the prediction for eruption and/or impaction in advance. Three hundred and thirty cases of orthopantomogram were employed and classified as mesial root-dominant group, distal root-dominant group and Identical group according to the radicular development of lower third molars. This presentation has carried out the incipient mesial inclination, radicular development, impaction/eruption rate and changes of mesial inclination of the very teeth. Consequently the following summary and conclusions were drawn; Radicular development dominated mesial root than the distal and dominant mesial root invited higher potentialities for normal eruption. The mesial or honzontal impactions were detected on the distal root-dominant group. This analysis has been suggested the potential eruption/impaction of lower third molars were dependent upon the radicular development and the incipient mesial inclination.

• Journal of information and communication convergence engineering
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• v.7 no.2
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• pp.193-198
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• 2009

The H.264/ AVC video coding standard supports the intra prediction with various block sizes for luma component and a 8x8 block size for chroma components. This new feature of H.264/AVC offers a considerably higher improvement in coding efficiency compared to previous compression standards. In order to achieve this, H.264/AVC uses the Rate-distortion optimization (RDO) technique to select the best intra prediction mode for each block size, and it brings about the drastic increase of the computation complexity of H.264 encoder. In this paper, a fast block size decision algorithm is proposed to reduce the computation complexity of the intra prediction in H.264/AVC. The proposed algorithm computes the smoothness based on AC and DC coefficient energy for macroblocks and compares with the nonparametric criteria which is determined by considering information on neighbor blocks already reconstructed, so that deciding the best probable block size for the intra prediction. Also, the use of non-parametric criteria makes the performance of intra-coding not be dependent on types of video sequences. The experimental results show that the proposed algorithm is able to reduce up to 30% of the whole encoding time with a negligible loss in PSNR and bitrates and provides the stable performance regardless types of video sequences.

• Journal of the Korean Geotechnical Society
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• v.19 no.1
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• pp.229-236
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• 2003

Ultrasonic propagation velocities of both the dilatational and shear waves through the weathered tuff soil sampled from the area tying between Ulanbator and Beijing were measured under temperature condition of near subzero by means of sing-around method. After comparing the results with obtained data on unfrozen water content, a linear relation between velocities and unfrozen water content was performed with high coefficient value. Experimental results of two kinds of rather uniform materials, namely, glass-beads and silica micro-beads, testified the similar linear relations. In addition, the change rate of dilatational wave velocities with the change of volumetric unfrozen water content was not dependent on soil type. Although a rational theory of the ultrasonic velocities dependence on the unfrozen water content is not yet proposed, the presented empirical relationships may suggest the appropriate evaluation to the effect of unfrozen water on dynamic characteristics of frozen soil.

• KSBB Journal
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• v.31 no.4
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• pp.219-227
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• 2016

Valsartan, a drug for the treatment of cardiovascular disease, exhibited low bioavailability which was caused by, at least in part, limited solubility at low pH. Present investigation deals with the preparation and characterization of gastro-retentive drug delivery system (GRDDS) using valsartan solid dispersion. We prepared solid dispersion using surfactants (Poloxamer 407) and alkalizer ($Na_2CO_3$) which may to be useful for improving solubility of valsartan at low pH and evaluated by saturated solubility of valsartan in distilled water. Valsartan gastro-retentive (GR) tablets containing solid dispersion prepared and evaluated by weight variation, floating time and dissolution rate. Compression at lower pressures resulted in the tablets floating over simulated gastric fluid (pH 1.2) for more than 17 h. In vitro release of valsartan from GR tablet was dependent on the amount of poloxamer 407 and hydroxypropyl methylcellulose. On the basis of evaluation parameter, formulation E-3 was selected as a final formulation. Therefore, it can be concluded that the GR tablets containing solid dispersion may be exploited successfully for the delivery of poorly drug such as valsartan.