• Proceedings of the Acoustical Society of Korea Conference
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• 1996.10a
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• pp.70-75
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• 1996

In this paper, the pre-precessing method for the recognition of single vowels by use of spectrum envelope is presented , we use new method of an extrating spectrum envelope using the diffusion filter bank. We reduced the total processing time, and got higher enhancement of discrimination . By getting 88.3% of average recognition rate for single vowels of real voice through computer simulation, we confirmed it to be useful for speech recongition which use spectrum analysis for voice signal to have many frequency components.

• Journal of Environmental Science International
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• v.11 no.7
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• pp.679-686
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• 2002

Turbulence greatly influence on atmospheric flow field. In the atmosphere, turbulence is represented as turbulent diffusion coefficients. To estimate turbulent diffusion coefficients in previous studies, it has been used constants or 2-level method which divides surface layer and Ekman layer. In this study, it was introduced Smagorinsky method which estimates turbulent diffusion coefficient not to divide the layer but to continue in vertical direction. We simulated 3-D flow model and TKE equation applied turbulent diffusion coefficients using two methods, respectively. Then we showed the values of TKE and the condition of each term to TKE. The results of Smagorinsky method were reasonable. But the results of 2-level method were not reasonable. Therefor, it had better use Smagorinsky method to estimate turbulent diffusion coefficients. We are expected that if it is developed better TKE equation and model with study of computational method in several turbulent diffusion coefficients for reasonably turbulent diffusion, we will able to predict precise wind field and movements of air pollutants.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.10
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• pp.8-15
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• 2020

The diffusion cell method is the main technique employed for the in vitro diffusion test of transdermal drug delivery preparations. Most existing transdermal diffusion devices use a water bath heating structure and direct current motor magnetic stirrer. However, these devices are confronted with problems, such as large volume, incompatible vertical and horizontal diffusion cells, few diffusion cell sets, and poor reliability. To overcome these deficiencies, the system adopts a dry heating method and uses a rotating magnetic field generated by the electromagnetic stirrer to drive the magnetic stirrer. Accordingly, the resulting device is characterized by a simple structure and small volume, convenient operation, compatible vertical and horizontal diffusion cells, and numerous diffusion cell sets. The reliability and practicability of the system is verified by the in vitro percutaneous permeability test of the bisoprolol patch.

• Proceedings of the KOSOMBE Conference
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• v.1997 no.11
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• pp.161-163
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• 1997

In this paper, a two-dimensional electron beam dose calculational algorithm implented for use in a two-dimensional radiation therapy planning system is described. The 2-D electron beam calculations have been in use clinically for a few decades. Our algorithm uses Age-diffusion model based int the Boltzman Transport Equation. Our implementation provides convenient user interface associated with electron beam therapy planning and displays radiation dose distribution according to different electron energy on patient images.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.11a
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• pp.21-24
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• 1998

The properties of ZrN layer deposited by Sputtering system have been investigated in the application of diffusion barrier layer to copper. ZrN layer exhibited a excellent barrier property up to $700^{\circ}$ and higher resistivity. If an excess $O_2$is protected during the process of ZrN deposition, ZrN layer will be possible to use a diffusion barrier layer to copper.

• 한국전산유체공학회:학술대회논문집
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• 2003.10a
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• pp.88-90
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• 2003

We implement Realtime Air Diffusion Prediction System which is designed for air diffusion simulations with four-dimensional data assimilation. For realtime running, we parallelize the system using MPI (Message Passing Interface) on distributed-memory parallel computers and build a cluster computer which links high-performance PCs with high-speed interconnection networks. We use 162­CPU nodes and a Myrinet network for the cluster

• Journal of Contemporary Eastern Asia
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• v.14 no.1
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• pp.45-55
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• 2015

This paper examines the diffusion of smartphones with a special emphasis on the diffusive interactions between Apple iOS and Google Android in a global context. Since the two mobile platforms were first introduced in the market, the use of smartphones has skyrocketed, suggesting that the dramatic diffusion of smartphones may be explained in part by the growth and competition of these two platforms. To study this, an extended Bass model is applied to a data set of quarterly smartphone sales between 2008 and 2013 for 15 countries. Our findings suggest that the innovation effect was more salient for iOS than for Android in developed countries, whereas the imitation effect was more striking for Android than for iOS in developing countries. Furthermore, our results from the co-diffusion model suggest that the diffusion of Android negatively affected by the diffusion of iOS, but not vice versa.

• Journal of Digital Convergence
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• v.14 no.3
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• pp.63-69
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• 2016

One of the biggest recent issues in the communication market is the explosive distribution of smartphones. One of the reasons why a smartphone could have seen this rapid distribution in terms of the service management is because it enables the access to the Internet without getting restricted by place and time through customization by a user, unlike a feature phone which only has the existing functions mounted on that were already chosen by a suppler. The other reason is because of its applications. This study aimed to make an empirical investigation of the impact of each of the different convenience types of mobile applications on the usage and the use diversity, consider the process of use diffusion, and find out whether there is a difference in the effect of each convenience type on the use-diffusion. According to the findings of this study, it was firstly shown that the effect of each convenience type on the use-diffusion is different, and secondly, it appeared that the more various functions of the mobile applications are used, the more usage increases.

• Journal of Information Technology Services
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• v.22 no.2
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• pp.41-56
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• 2023

Metaverse is a three-dimensional virtual space where virtual and reality interact and co-evolutionize, and social, cultural, and economic activities are carried out in it to create value. Among the types of metaverse, the virtual world metaverse is expected to bring innovation beyond time and space in all areas of industry and society following the Internet. This study empirically analyzed factors affecting consumer's intention to use the virtual world metaverse by an innovation diffusion perspective. It was analyzed as an expanded technology acceptance model by setting relative advantages, ease of use, and visibility among the attributes of the innovation diffusion, and social presence, telepresence, and interactivity among the characteristics of the virtual worlds as factors. The proposed research model and hypothesis were verified through a PLS structural equation analysis based on a survey of 216 people. Studies have shown that relative advantage, telepresence, and interactivity have a significant effect on perceived usefulness and perceived enjoyment, but visibility does not have a significant effect on perceived usefulness and perceived enjoyment. It was found that ease of use had a positive effect on perceived enjoyment, social presence had a positive effect on perceived usefulness, and perceived usefulness and perceived enjoyment had a positive effect on the intention to use, respectively. This study is meaningful in that it empirically analyzed the factors affecting the intention to use the virtual world metaverse by dividing the psychological characteristics that induce consumer behavior into perceived usefulness which is an extrinsic motivation and perceived enjoyment which is an intrinsic motivation.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.6
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• pp.485-491
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• 2013

Recently, with the proliferation of social network services, users and many companies hope that their information spread more faster. In order to study the information diffusion in the social networks, many algorithms such as greedy algorithm and heuristic algorithm have been proposed. However, the greedy algorithm is too complicated to use in real-life social network, and the heuristic algorithms have been studied under the uniform distribution of diffusion probability, which is different from the real social network property. In this paper, we propose an heuristic information diffusion maximization algorithm based on diffusion probability and node degree. For performance evaluation, we use real social network database, and it is verified that our proposed algorithm activates more active nodes than existing algorithms, which enables faster and wider information diffusion.