• Proceedings of the Korean Society of Computer Information Conference
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• 2016.01a
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• pp.147-148
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• 2016

The purpose of this paper is to investigate the diffusion process of mobile internet use in Korea and to explore the determinants driving MIU. A survey was conducted to collect data to empirically assess the research model. In total, 543 usable responses were collected using a questionnaire derived from previous research. Both the structural equation model and partial least squares were used to study the model concerning different user groups. Findings, The results indicate that there are significant differences in the users' perceptions of mobile internet usage during its different innovation diffusion stages. Of the determinants, perceived enjoyment is the most important predictor of mobile internet use. In addition to motivating users by making services more enjoyable, the findings suggest that practitioners should take the differences of adopter groups into account. Making the mobile internet easy to use and compatible with users' lifestyles would promote the use of technology as well.

• Journal of Information Technology Services
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• v.8 no.1
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• pp.11-27
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• 2009

Recently, IPTV attracts great attention along with the digital convergence of communication and media technologies. This study examined critical factors on the consumer's continued use of the IPTV service. Based on the expectation-confirmation theory and the innovation diffusion theory, we derived nine key factors in the research model-relative advantage, compatibility, ease of use, image, diversity of contents, interactivity, monetary value, social influence, and user satisfaction. Using the partial least square method, we found that content diversity and compatibility have a significant indirect effect on the continued use of the IPTV service via user satisfaction, and user satisfaction and social influence also have a significant direct impact on the IPTV use. These findings not only provide practical insights on the consumer acceptance of new technology-converging services, but also help managers to plan their marketing strategies better.

• Journal of applied mathematics & informatics
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• v.30 no.3_4
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• pp.677-683
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• 2012

W.Choi([1]) obtains a complete description of ergodic property and several property by making use of the semigroup method. In this note, we shall consider separately the martingale problems for two operators A and B as a detail decomposition of operator L. A key point is that the (K, L, $p$)-martingale problem in population genetics model is related to diffusion processes, so we begin with some a priori estimates and we shall show existence of contraction semigroup {$T_t$} associated with decomposition operator A.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.295-296
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• 2009

It is often the case with the durability design to use diffusion coefficient obtained from experimental test. From the analytic solution considering the starting time of exposure, it is confirmed that the diffusion coefficient from NT BUILD 443 underestimates real reference value.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.255-256
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• 2003

Simulations of atmospheric diffusion process under stable and unstable conditions were carried out using both numerical and experimental methods. Results from the previous study show that numerical simulation using 3-dimensional incompressible Navier-Stokes equation and density deviation are in good agreement with typical plume pattern. In this study, we use experimental data of temperature and wind profile obtained from a thermally stratified wind tunnel as initial conditions for numerical simulation and compare the results.

• The Journal of Bigdata
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• v.7 no.1
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• pp.193-212
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• 2022

The Bass Diffusion Model is one of the most successful models in marketing research, and management science in general. Since its publication in 1969, it has guided marketing research on diffusion. This paper illustrates the usage of the Bass diffusion model, using mobile cellular subscription diffusion as a context. We fit the bass diffusion model to three large developed markets, South Korea, Japan, and China, and the emerging markets of Vietnam, Thailand, Kazakhstan, and Mongolia. We estimate the parameters of the bass diffusion model using the nonlinear least square method. The diffusion of mobile cellular subscriptions does follow an S-curve in every case. After acquiring m, p, and q parameters we use k-Means Cluster Analysis for grouping countries into three groups. By clustering countries, we suggest that diffusion rates and patterns are similar, where countries with emerging markets can follow in the footsteps of countries with developed markets. The purpose was to predict the timing and the magnitude of the market maturity and to determine whether the data follow the typical diffusion curve of innovations from the Bass model.

• Journal of applied mathematics & informatics
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• v.36 no.1_2
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• pp.135-154
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• 2018

In this paper, an almost second order overlapping Schwarz method for singularly perturbed third order convection-diffusion type problem is constructed. The method splits the original domain into two overlapping subdomains. A hybrid difference scheme is proposed in which on the boundary layer region we use the combination of classical finite difference scheme and central finite difference scheme on a uniform mesh while on the non-layer region we use the midpoint difference scheme on a uniform mesh. It is shown that the numerical approximations which converge in the maximum norm to the exact solution. We proved that, when appropriate subdomains are used, the method produces convergence of second order. Furthermore, it is shown that, two iterations are sufficient to achieve the expected accuracy. Numerical examples are presented to support the theoretical results. The main advantages of this method used with the proposed scheme are it reduce iteration counts very much and easily identifies in which iteration the Schwarz iterate terminates.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.461-466
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• 2000

To improve the quality of concrete, we usually consider the reduction of water/cement ratio, the increase of concrete cover depth and the use of mineral admixtures. Reportedly, the use of admixtures make concrete more durable and tighten against water. But, it is needed to study more about the relationship between the admixtures and the chloride ion diffusion. Therefore, in this study, we focused on the chloride ion diffusion properties of the pozzolanic admixtures such as fly-ash, slag and silica fume which are known as being useful on chloride attack resistance when mixed into mortar or concrete. Furthermore, we treed to analyze the correlation between mortar and concrete using the admixture, which is useful for analyzing chloride ion diffusion mechanism.

• Journal of applied mathematics & informatics
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• v.36 no.3_4
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• pp.181-203
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• 2018

In this paper, we have constructed an overlapping Schwarz method for singularly perturbed second order convection-diffusion equations. The method splits the original domain into two overlapping subdomains. A hybrid difference scheme is proposed in which on the boundary layer region we use the central finite difference scheme on a uniform mesh while on the non-layer region we use the mid-point difference scheme on a uniform mesh. It is shown that the numerical approximations which converge in the maximum norm to the exact solution. When appropriate subdomains are used, the numerical approximations generated from the method are shown to be first order convergent. Furthermore it is shown that, two iterations are sufficient to achieve the expected accuracy. Numerical examples are presented to support the theoretical results. The main advantages of this method used with the proposed scheme is it reduces iteration counts very much and easily identifies in which iteration the Schwarz iterate terminates.

• Journal of the Korean Society of Safety
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• v.11 no.3
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• pp.66-74
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• 1996

Numerical simulations were carried out using standard Reynolds stress turbulence model(LRR model) and modified RSM(Janicka model ) to validate these models in combustion flow fields. Two flames were selected for use as a benchmark data for model testing. One is a conventional jet diffusion flame that has the effect of suppression of turbulence by combustion. The other is a triple jet diffusion flame that designed to give high turbulence to the periphery of the flame and to remove the low Reynolds-number flow fields. As a result, it was found that the modification of standard RSM model is indispensable in the modelling of flames with low turbulence region. And it is also necessary to improve the existing modified models for the universal use.