• Korean Journal of Hydrosciences
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• 제1권
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• pp.1-14
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• 1990

The analytical diffusion model is first formulated and its characteristics are critically reviewed. The flood events during the 1985-1986 flood seasons in the IHP Pyungchang Representative Basin are routed by this model and are compared with those routed by the kinematic wave model. The present model is proven to be an excellent means of taking the backwater effects due to lateral inflow or downstream river stage variations into consideration in channel routing of flood flows. It also requires much less effort and computing time at a desired station compared to any other reliable flood routing methods.

• 한국경영과학회지
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• 제27권2호
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• pp.81-96
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• 2002

Telecommunication services are distinctive in that their adoptions are influenced by network effect resulting in 'the late take-off phenomenon' and the 'critical mass' problem. In this paper we examined, so called, 'the late take-off phenomenon' in the diffusion process of telecommunication services. We compared the parameters of the diffusion process of consumer durables with those of fax services in the US and Korea. By analyzing the parameters of a new diffusion model based on the threshold model proposed by Markus, we found that 'the late take-off phenomenon' resulted from the low heterogeneity of the threshold distribution for the potential adopters. A simulation approach was proposed for the theoretical implication of the 'critical mass' problem in the start-up telecommunications services.

• 환경위생공학
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• 제23권3호
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• pp.47-57
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• 2008

This study was predicted the diffusion of the conservative contaminant using a two-dimensional hydraulic model. The research area is upper basin of Jakwang river where the possibility where the pollutant of vast quantity will flow is high. Using SMS model, we calculated two-dimensional stream flow. And using this result, predicted the conduct of the conservative contaminant by pollutant transfer diffusion calculation. And also we predicted flow and contaminant diffusion in the near estuary by constructed guide bank. As a result of study, pollutant effect scope of the conservative contaminant was predicted with the fact that will broaden because of interception by guide bank. As discharge was increased from the Jakwang river, The diffusion of the pollutant is accelerated, also the effect scope increases.

• 유통과학연구
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• 제14권5호
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• pp.71-80
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• 2016

Purpose - In case of automobile parts, there has been a lot of progress in the study on supplier development plans and SCM in industrial progress study as well as on the relationship between ERP and SCM. But supplier development program providers have researched on SCM performance in accordance with the interests of the supplier development program most, thus, buyers were knowledgeable about the earlier program performance. Therefore, the purpose of this study is to prove correlation factor, supplier factor, purchaser factor affecting SCM performance and ERP activating diffusion through the process of supplier development. Supplier development maturity formation model is considered important variables as mediators related to the procedure. Finally, the performance formation model of the supplier development maturity through supplier development factor would be presented as the outcome of this study. Research design, data, and methodology - Data gathering was as follows: questionnaires were delivered to 87 companies that have business connection with H Company. The empirical research to test our hypothesis was grounded on statistical analysis (adapting SPSS 19.0 & AMOS 19.0). The hypothesis is that the supplier development factor variables consist of correlation factor, supplier factor, purchaser factor, and have non-negative effects on the next variables: mediators such as supplier development maturity; and the supplier development maturity variables have a positive effect on the next variables: ERP activating diffusion, ERP activating diffusion has a non-negative effect on supply chain performance. We experimented the hypothesized model using path analysis with latent variables. Results - First, it was known that cooperation

, reliability

, comprehension on the purpose of SDP

, adaptation of change

, knowledge transfer program

, have significant positive effects on supplier development maturity. Second, supplier development maturity has positive effects significantly on ERP activating diffusion

. Finally, the causal relationships from ERP activating diffusion to SCM performance were significantly accepted. Its significance, as through the hypotheses, presented a structural model for the elaboration, suppliers develop maturity, and ultimately SCM performance that affect ERP leveraging spread beyond the concept of maturity of information system. Therefore, it was a mainstay of research on the existing ERP has they believed. Conclusion - First, with the fast changes in business circumstances, company should get the right information to implement SCM appropriately. For successful SCM, firms should understand the supplier development maturity formation and ERP activating diffusion. Second, supplier development factor has significant effects on supplier development maturity. Third, mediator such as supplier development maturity significantly affects ERP activating diffusion. Finally, ERP activating diffusion has significant impacts on SCM performance. This study makes a meaningful contribution to further appreciation on how supplier development maturity formation affects SCM performance. This study shows implications. First, there would not have been dealt with introducing the concept of supplier development maturity. Second, through empirical analysis and provider factors, the providers will develop the maturity that affect interactive factors between purchaser and supplier.

• Computers and Concrete
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• 제8권2호
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• pp.125-142
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• 2011

In the present paper, a numerical simulation method based on mesoscopic composite structure of concrete, the truss network model, is developed to evaluate the diffusivity of concrete in order to account for the microstructure of concrete, the binding effect of chloride ions and the chloride concentration dependence. In the model, concrete is described as a three-phase composite, consisting of mortar, coarse aggregates and the interfacial transition zones (ITZs) between them. The advantage of the current model is that it can easily represent the movement of mass (e.g. water or chloride ions) through ITZs or the potential cracks within concrete. An analytical method to estimate the chloride diffusivity of mortar and ITZ, which are both treated as homogenious materials in the model, is introduced in terms of water-to-cement ratio (w/c) and sand volume fraction. Using the newly developed approaches, the effect of cracking of concrete on chloride diffusion is reflected by means of the similar process as that in the test. The results of calculation give close match with experimental observations. Furthermore, with consideration of the binding capacity of chloride ions to cement paste and the concentration dependence for diffusivity, the one-dimensional nonlinear diffusion equation is established, as well as its finite difference form in terms of the truss network model. A series of numerical analysises performed on the model find that the chloride diffusion is substantially influenced by the binding capacity and concentration dependence, which is same as that revealed in some experimental investigations. This indicates the necessity to take into account the binding capacity and chloride concentration dependence in the durability analysis and service life prediction of concrete structures.

• Structural Engineering and Mechanics
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• 제75권2호
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• pp.133-144
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• 2020

This investigation is to study the effect of gravitational field and diffusion on a microstretch thermoelastic medium heating by a non-Gaussian laser beam. The problem was studied in the context of the dual-phase-lag model. The normal mode analysis is used to solve the problem to obtain the exact expressions for the non-dimensional displacement components, the micro-rotation, the stresses, and the temperature distribution. The effect of time parameter, heat flux parameter and gravity response of three theories of thermoelasticity i.e. dual-phase-lag model (DPL), Lord and Shulman theory (L-S) and coupled theory (CT) on these quantities have been depicted graphically for a particular model.

• Korean Journal of Hydrosciences
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• 제8권
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• pp.111-123
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• 1997

A one-dimensional eddy diffusion model and a mixed-layer model are developed and applied to simulate the vertical temperature profiles in lakes. Also the running result of each method are compared and analyzed. In an eddy diffusion model, molecular diffusivity is neglected and eddy diffusivity which does not need lake-specific fitting parameter and constant lake's level are applied. The heat exchanges at the water surface and the bottom are formulated by the energy balance and zero energy gradient, respectively. In a mixed-layer model, two layers approach which has a constant thickness is adopted. The application of these models which use explicit finite difference and Runge-Kutta methods respectively demonstrates that the models simulate water temperatures efficiently.

• Computers and Concrete
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• 제15권1호
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• pp.127-140
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• 2015

The process of chloride ingress in saturated concrete was presented by a previous study that used a mathematical model for the same as that concrete. This model is to be studied chloride ion diffusion which is considered as a chemical phenomenon and is to be represented the chloride diffusion process to be a nonlinear partial differential equation (PDE). In this paper, this nonlinear PDE is solved by the Kirchhoff transformation to render into a linear PDE. This linear PDE associated with initial and boundary conditions is also solved by the Laplace transformation to obtain an analytical solution. To verify the serviceability and reliability of this proposed method, the practical application should be supplied. The input parameters were cited from the previous study. The free chloride concentration profiles obtained by the analytical solution of mathematical model for saturated concretes after 24 and 120 hrs of exposure were compared with the previous study. The predicted results obtained from proposed method have a tendency with experimental results obtained by the previous study and trend toward numerical results approximated by finite difference technique.

• 대한산업공학회지
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• 제42권3호
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• pp.222-230
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• 2016

As the global game market has been more competitive, it has been important to analyze success factors of game products. In this paper, we applied a Bass Diffusion Model and Clustering Analysis to identify the success factors of games based on data from Steam, an international game platform. By using a diffusion model, we first categorize game products into two groups : successful and unsuccessful games. Then, each group has been analyzed by using clustering analysis based on product features such as genres, price, and minimum system requirements. As a result, success factors of a game have been identified. The result shows that customers in game industry appreciate sophisticated contents. Unlike many other industries, price is not considered as a key success factor in the game industry. Expecially, advanced independent video games (commonly referred to as indie games) with killer contents show competitiveness in the market.

• Korea-Australia Rheology Journal
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• 제18권2호
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• pp.51-65
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• 2006

Of concern in the present theoretical investigation is the study of blood flow and convection-dominated diffusion processes in a model bifurcated artery under stenotic conditions. The geometry of the bifurcated arterial segment having constrictions in both the parent and its daughter arterial lumen frequently appearing in the diseased arteries causing malfunction of the cardiovascular system, is constructed mathematically with the introduction of suitable curvatures at the lateral junction and the flow divider. The streaming blood contained in the bifurcated artery is treated to be Newtonian. The flow dynamical analysis applies the two-dimensional unsteady incompressible nonlinear Wavier-Stokes equations for Newtonian fluid while the mass transport phenomenon is governed by the convection diffusion equation. The motion of the arterial wall and its effect on local fluid mechanics is, however, not ruled out from the present model. The main objective of this study is to demonstrate the effects of constricted flow characteristics and the wall motion on the wall shear stress, the concentration profile and on the mass transfer. The ultimate numerical solutions of the coupled flow and diffusion processes following a radial coordinate transformation are based on an appropriate finite difference technique which attain appreciable stability in both the flow phenomena and the convection-dominated diffusion processes.