• Nuclear Engineering and Technology
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• v.45 no.7
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• pp.827-838
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• 2013

Interaction layer growth between U-Mo alloy fuel particles and Al in a dispersion fuel is a concern due to the volume expansion and other unfavorable irradiation behavior of the interaction product. To reduce interaction layer (IL) growth, a small amount of Si is added to the Al. As a result, IL growth is affected by the Si content in the Al matrix. In order to predict IL growth during fabrication and irradiation, empirical models were developed. For IL growth prediction during fabrication and any follow-on heating process before irradiation, out-of-pile heating test data were used to develop kinetic correlations. Two out-of-pile correlations, one for the pure Al matrix and the other for the Al matrix with Si addition, respectively, were developed, which are Arrhenius equations that include temperature and time. For IL growth predictions during irradiation, the out-of-pile correlations were modified to include a fission-rate term to consider fission enhanced diffusion, and multiplication factors to incorporate the Si addition effect and the effect of the Mo content. The in-pile correlation is applicable for a pure Al matrix and an Al matrix with the Si content up to 8 wt%, for fuel temperatures up to $200^{\circ}C$, and for Mo content in the range of 6 - 10wt%. In order to cover these ranges, in-pile data were included in modeling from various tests, such as the US RERTR-4, -5, -6, -7 and -9 tests and Korea's KOMO-4 test, that were designed to systematically examine the effects of the fission rate, temperature, Si content in Al matrix, and Mo content in U-Mo particles. A model converting the IL thickness to the IL volume fraction in the meat was also developed.

• Information Systems Review
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• v.5 no.2
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• pp.37-51
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• 2003

Mobile business noticed as a constructive alternative of e-commerce and e-business is being diversely considered as a new form or subset of e-business. In this study, mobile business is defined as a comprehensive alternative including e-business. The framework of the superset of e-business has two axes: connectivity and mobility. In addition, various cases based on the combination of the components are provided and explained. It is the main characteristic of this study that the element of off-line "mobility" is added to "connectivity" generally used while explaining e-commerce and e-business. For place (or location) is a prerequisite for the feature of mobility, we grope for why and how Location-Based Service (LBS) will take an important role in the development of new e-business models and services. As the real and full-scale beginning of IMT-2000 service and the rapid progress and diffusion of mobile communications services including wireless LAN require an immense and innovative way of thinking about e-commerce and e-business, the framework suggested in this study is considered to go far toward satisfying the new needs in this area.

• Journal of Internet Computing and Services
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• v.15 no.2
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• pp.41-47
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• 2014

In this paper, we implemented a CUDA Fortran parallel program to run the CFD_NIMR model on GP-GPU's, which simulates air diffusion on urban terrains. A GP-GPU is graphic processing unit in the form of a PCI card, and a general calculation accelerator to perform a large amount of high speed calculations with low cost and electric power. The GP-GPU gives performance enhancement of speed by 15 times to compare the Nvidia Tesla C1060 GPU with Intel XEON 2.0 GHz CPU. In addition, the program on a GP-GPU shows efficient performance compared to an MPI parallel program on multiple CPU's. It is expected that a proposed programming method on the GP-GPU parallel program can be used for numerical models with a similar structure.

• Journal of Soil and Groundwater Environment
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• v.13 no.3
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• pp.21-26
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• 2008

Nitrate adsorption from aqueous solutions onto zinc chloride ($ZnCl_2$) treated coconut Granular Activated Carbon (GAC) was studied in a batch mode at two different initial nitrate concentrations (25 and 50 mg/L). The rate of nitrate uptake on prepared media was fast in the beginning, and 50% of adsorption was occurred within 10 min. The adsorption equilibrium was achieved within one hour. The mechanism of adsorption of nitrate on $ZnCl_2$ treated coconut GAC was investigated using four simplified kinetic models : the rate parameters were calculated for each model. The kinetic analysis indicated that pseudo-second-order kinetic with pore-diffusion-controlled was the best correlation of the experimental kinetic data in the present adsorption study.

• KIPS Transactions on Software and Data Engineering
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• v.8 no.7
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• pp.275-288
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• 2019

In this paper, we consider a rumor source inference problem when sufficiently many nodes heard the rumor in the network. This is an important problem because information spread in networks is fast in many real-world phenomena such as diffusion of a new technology, computer virus/spam infection in the internet, and tweeting and retweeting of popular topics and some of this information is harmful to other nodes. This problem has been much studied, where it has been shown that the detection probability cannot be beyond 31% even for regular trees if the number of infected nodes is sufficiently large. Motivated by this, we study the impact of query that is asking some additional question to the candidate nodes of the source and propose budget assignment algorithms of a query when the network administrator has a finite budget. We perform various simulations for the proposed method and obtain the detection probability that outperforms to the existing prior works.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.19 no.2
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• pp.151-159
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• 2019

As the era of big data, which is the foundation of the fourth industry, has come, most related industries are developing related solutions focusing on the technologies of data storage, statistical analysis and visualization. However, for the diffusion of bigdata technology, it is necessary to develop the prediction analysis technologies using artificial intelligence. But these advanced technologies are only possible by some experts now called data scientists. For big data-related industries to develop, a non-expert, called a citizen data scientist, should be able to easily access the big data analysis process at low cost because they have insight into their own data. In this paper, we propose a system for analyzing bigdata and building business models with the support of easy-to-use analysis system without knowledge of high-level data science. We also define the necessary components and environment for the prediction analysis system and present the overall service plan.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.189-195
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• 2019

In this work, the flow and combustion characteristics using a 3-D numerical simulation was evaluated for a shale gas fueled combustor in a commercial class gas turbine. The Standard k-e turbulence model, 2 step methane oxidation mechanism, Finite rate/Eddy dissipation reaction model, DTRM radiation model were employed and validated well at the baseline condition (Natural Gas, Pilot Ratio 0.2). Based on the validated models, the combustion characteristics of shale gas was evaluated for three pilot ratios cases. It was found that NOx concentrations for all shale gas cases were less than the that for city gas, which imply that, at the selected PRs, the condition for combustion stability is satisfied. In addition, for higher PR, whereas the average temperatures at the exit are the same, the NOx increases. It means that diffusion combustion portion increases due to the higher PR.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.13 no.1
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• pp.147-155
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• 2003

The diffusion of internet infrastructure and a fast increase of Population to use it is becoming a base of the service that can use various information, data and digital contents which were provided through off-line physically and used. Recently, the. techniques for copy deterrence and copyright protection have been important in e-commerce because various contents in digital form can be duplicated easily. The Access Control(AC) technique that only a user having the qualifications can access and use contents normally has been studied. The Conditional Access System(CAS) used in a satellite broadcasting md Digital Right Management System(DRMS) used for contents service are representative models of current commercialized access control. The CAS and DRM can be considered as an access control technique based on the payment based type(PBT). This paper describe the access control method of payment free type(PFT) suggested in ［5］ which are independent on the payment structure. And then we suggest a new access control method of payment free type which is more efficient than the previous one.

• The Journal of Information Systems
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• v.30 no.4
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• pp.119-152
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• 2021

The concept of Self-Sovereign Identity (SSI) has emerged to overcome the limitations of traditional centralized personal identity management systems in our society. Therefore, in this study, 36 seminal researches out of 112 collected studies were investigated with a systematic literature review method to deliver a core common definition as well as the research trends on SSI in the socioeconomic, legal and technological fields. SSI studies in the legal field have mainly considered the conflicts with relevant laws such as General Data Protection Regulation (GDPR) and privacy protection laws. The study of SSI in the technology field have looked at the trends of the technical components to implement SSI and discussed the necessities of establishing standards to increase interoperability for SSI diffusion worldwide. This study ultimately derived the core definition of SSI from a various academic fields as "a trust-based personal identity management system that enables autonomous self-identification by a identity owner without a centralized system or 3rd party intervention". The results of this study contribute to the understanding of the essential SSI concept which were varied on different research fields and industries. The results also provide a foundation for discovering various SSI-based business models, applications as well as future research opportunities. Furthermore, this study suggested that SSI must be developed with interdisciplinary manner among the socioeconomic, legal, and technological fields to be practically applicable system to enable autonomous self-identification by a identity owner in our society.

• Nuclear Engineering and Technology
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• v.54 no.8
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• pp.3059-3072
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• 2022

A Jacobian-Free Newton Krylov Two-Nodal Coarse Mesh Finite Difference algorithm based on Nodal Expansion Method (NEM_TNCMFD_JFNK) is successfully developed and proposed to solve the three-dimensional (3D) and multi-group reactor physics models. In the NEM_TNCMFD_JFNK method, the efficient JFNK method with the Modified Incomplete LU (MILU) preconditioner is integrated and applied into the discrete systems of the NEM-based two-node CMFD method by constructing the residual functions of only the nodal average fluxes and the eigenvalue. All the nonlinear corrective nodal coupling coefficients are updated on the basis of two-nodal NEM formulation including the discontinuity factor in every few newton steps. All the expansion coefficients and interface currents of the two-node NEM need not be chosen as the solution variables to evaluate the residual functions of the NEM_TNCMFD_JFNK method, therefore, the NEM_TNCMFD_JFNK method can greatly reduce the number of solution variables and the computational cost compared with the JFNK based on the conventional NEM. Finally the NEM_TNCMFD_JFNK code is developed and then analyzed by simulating the representative PWR MOX/UO₂ core benchmark, the popular NEACRP 3D core benchmark and the complicated full-core pin-by-pin homogenous core model. Numerical solutions show that the proposed NEM_TNCMFD_JFNK method with the MILU preconditioner has the good numerical accuracy and can obtain higher computational efficiency than the NEM-based two-node CMFD algorithm with the power method in the outer iteration and the Krylov method using the MILU preconditioner in the inner iteration, which indicates the NEM_TNCMFD_JFNK method can serve as a potential and efficient numerical tool for reactor neutron diffusion analysis module in the JFNK-based multiphysics coupling application.