• Proceedings of the Korea Concrete Institute Conference
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• 2004.11a
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• pp.225-228
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• 2004

In order to estimate the chloride ion penetration, the model, which considers diffusion and sorption, is proposed on the basis of Finite Element Method (FEM). The FEM program provides the estimation of chloride concentration according to cyclic humidity and sorption. After the humidity diffusion analysis is carried out, the chloride ion diffusion and sorption analysis are conducted on the basis of the preestimated humidity data in each element. Each element has different analysis variables at different ages and locations. At early ages and constant outer humidity, the difference between inner and outer relative humidity causes the chloride ion penetration by sorption. As the humidity diffusion reduces the difference with age, the effect of sorption on the chloride ion penetration decreases. By the way, the cyclic humidity increases the effect of sorption on the chloride ion penetration at early ages, and the quantity of chloride ion around steel at later ages. Therefore, the in-situ analysis of chloride ion penetration for marine concrete structures must be performed considering the cyclic humidity condition and the long term sorption.

• Journal of the Korean Society of Clothing and Textiles
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• v.37 no.6
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• pp.725-736
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• 2013

This study segments information users according to depth and variety of use diffusion in order to differentiate between the influence of fashion information spread and diffusions from each segmented group. Data were collected from a fashion community to perform a social network analysis that used UCINET 6.0. Members completed the survey materials and the network materials were utilized in the analysis to test the hypothesis. The segmented groups of information users determined the study results according to use diffusion and the variables that affect them. The variables affecting information diffusion outcomes indicate different significant influence factors on each segmented market. Information variety and complexity represents elevated information reproductions and verbal acceptances from information diffusion outcomes.

• Journal of Advanced Navigation Technology
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• v.16 no.4
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• pp.657-664
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• 2012

One of the methods to transmit solute through solvent is diffusion. Various particles or molecules including several charged ions in the body diffuse from high density region to low density due to density difference or external electric field. This kind of mechanism is due to thermal motion of each solute molecules. These situations can be deployed using Fick's first and second laws that govern diffusion phenomena in the body. I analysis these diffusion status of material in the body using above mentioned Fick's laws and then implement them through illustration.

• Journal of Fisheries and Marine Sciences Education
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• v.16 no.1
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• pp.11-20
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• 2004

The purpose of this study was to analyze of career exploration and career decision-making by identity statuses(diffusion, foreclosure, moratorium, achievement) of vocational high school students. The research questions were formulated as follows. (1) Is there a difference in identity statuses by level of the career exploration? (2) Is there a difference in identity statuses by level of the career decision-making? (3) How much identity statuses-identity diffusion, identity foreclosure, identity moratorium, identity achievement-effect to the career exploration and career decision-making? 255 vocational high school students in Pusan were sampled. For the statistical analysis, Oneway, analysis of covariance structure by AMOS 4.0 was applied. The results of the study were as follows. (1) The identity diffusion was low in the level of career exploration, but the identity moratorium and achievement were high in the level of career exploration. (3) The identity diffusion was low in the level of career decision-making, but the identity achievement was high in the level of career decision-making. (4) The identity diffusion effected to negatively career exploration and career decision-making, identity foreclosure effected to low positively career exploration and career decision-making, identity moratorium effected to positively career exploration but negatively career decision-making, identity achievement effected to positively career exploration and career decision-making.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.22 no.6
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• pp.607-615
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• 2009

Analysis of chloride penetration into concrete is performed considering the repeated wetting and drying conditions of tidal zone, by means of the developed finite element program which enables the diffusion-convection analysis to be conducted. Heat conduction and moisture diffusion are also included in the finite element analysis program in order that their effects to chloride penetration may be considered. For the efficiency of calculation, the analyses of temperature, relative humidity and free chloride concentration are conducted successively in that order, by treating the convection of chloride due to moisture diffusion as an source or sink term. By comparing the analysis result from finite element analysis, where main variable is a wetting and drying period, with the chloride profiles from ACI Life-365 method, it is shown that the Life-365 method gives an accurate result for the submerged zone but does not consider the differences of wetting and drying period. To obtain an accurate chloride profile in the tidal zone, it is confirmed that the diffusion-convection finite element analysis should be applied.

• The Journal of Sustainable Design and Educational Environment Research
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• v.4 no.4
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• pp.1-18
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• 2004

Research has been carried out to study thermal environment in a classroom under three kinds of air diffusion temperature and six kinds of air diffusion direction for ceiling type air conditioner. The velocity and temperature distributions of air in the room calculated by 3-dimensional numerical method(PHOENICS), This present study was also conducted to calculate the Air Diffusion Performance Index(ADPI) for cooling conditions and Predicted Percentage of Dissatisfied(PPD) for heating conditions. This analysis shows that the optimum angle of ceiling type air conditioner's diffusion is $15{\sim}30^{\circ}$ for cooling mode and about $15{\sim}45^{\circ}$ for heating mode in these calculating conditions. And also analysis has been carried out to evaluate thermal comfort of vertical and horizontal cross section of classroom.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.269-272
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• 2006

Chloride ion diffusion is the most important thing of occuring deterioration in RC structure. So it is important to decide the precise chloride ion diffusion coefficient in order to predict the durability life in RC structure. The purpose of this study is to analyze the established data, which are restricted by chloride diffusion coefficient, and to calculate chloride ion diffusion coefficient using RCPT test. To examine the prediction of the concrete structure durability by an FEM analysis and the chloride diffusion coefficient as a variable. Each surface finishing materials were effective on the increment of chloride penetration resistance, but showed a little different effect depending on the type of surface finishing material.

• Bulletin of the Korean Chemical Society
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• v.17 no.2
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• pp.192-198
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• 1996

We present a theoretical formulation of diffusion process on solid surface based on multidimensional transition state theory (TST). Surface diffusion of single adatom results from hopping processes on corrugated potential surface and is affected by surface vibrations of surface atoms. The rate of rare events such as hopping between lattice sites can be calculated by transition state theory. In order to include the interactions of the adatom with surface vibrations, it is assumed that the coordinates of adatom are coupled to the bath of harmonic oscillators whose frequencies are those of surface phonon modes. When nearest neighbor surface atoms are considered, we can construct Hamiltonians which contain terms for interactions of adatom with surface vibrations for the well minimum and the saddle point configurations, respectively. The escape rate constants, thus the surface diffusion parameters, are obtained by normal mode analysis of the force constant matrix based on the Hamiltonian. The analysis is applied to the diffusion coefficients of W, Ir, Pt and Ta atoms on the bcc(110) plane of W in the zero-coverage limit. The results of the calculations are encouraging considering the limitations of the model considered in the study.

• Journal of Korea Technology Innovation Society
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• v.20 no.4
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• pp.1243-1261
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• 2017

Mobile telecom markets have dramatically increased in the last decade due to a remarkable subscriber base growth. The diffusion patterns of the services are a major concern for mobile carriers preparing those new services. We assume that the diffusion patterns of those services will be similar to those of previous mobile services, and discovering the diffusion patterns of those services is an essential task of mobile carriers for preparing the next mobile services. This study attempts to classify some groups which show similar diffusion patterns of mobile services. Using a traditional diffusion model, this study estimates diffusion patterns of twenty five western European countries. The estimation is based on the monthly penetration ratio of those countries from 1993 to 2004. Based on the estimation, the cluster analysis discovers that there are two different countries groups in terms of mobile diffusion pattern: high imitation countries and low imitation countries. The critical point for classifying the two groups in terms of imitation effect was 0.90. The results provide the basis for developing a causal relationship model which explains the different diffusion pattern of mobile services and planning new networks for the advanced mobile services.

• Journal of Technology Innovation
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• v.9 no.2
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• pp.56-76
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• 2001

The main purpose of this study is to analyse the digital divide and th determinants of ICT diffusion rate in Korean industries. We estimate the ICT diffusion function using the pooling data for this analysis. The results are as follows. First, the ICT capital accumulated in machinery & equipment, electrical machinery and construction industry is estimated to be 83% of total In capital stock in the 90s. Second, using the panel analysis, we find positive correlation among ICT diffusion, network effect and accumulation of human capital, which is more prominent in the service sector. Third, the estimation results show that the additional 1% increase of human capital accumulation will allow to increase the 0.69% of ICT capital intensity in Korean industries.