• The Journal of the Korea Contents Association
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• v.18 no.3
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• pp.138-147
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• 2018

The network analysis is done to explore what kind if issues are diffused about earthquake and the role of social media. The types of disaster information is classified into formal and informal. The role of actor is classified based on the concentrativeness and the diffusion of issue. Youttube is functioned as a formal channel and an informal channel when disaster happened. In case of government's video, issue contractiveness is high but the diffusion is low. In case of media's video, issue contractiveness and the diffusion are all high. In case of individual channel, issue contractiveness is low, but diffusion is high. In disaster, youtube is a tool to respread the disaster issue. Government needs to try diffusion of government's news actively in disaster.

• Journal of Internet Computing and Services
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• v.19 no.4
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• pp.15-26
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• 2018

This study focused on the difference of the volume of sanitory pad issue and The aim of this study is to explore the relationship between the characteristics of SNS and the diffusion of issue in the process of crisis issue. SNS is categorized into communication diffusion, communication restriction,, diffusion, restriction base on the media interactivity and the user interactivity, In case of Twitter, media interactivity is low and user interactivity is low. In case of Youtube, media interactivity and user interactivity are all high. Crisiss issue is interactively diffused via Youtube compared to via Twitter. There was a negative public opinion in social media even if the government and the manufacturer said that there was no harm in the sanitary goods. In conclusion, this study highlights the importance of social media environment in the diffusion of information. The government prepared for the use of SNS in crisis because there was a negative opinion on the government and the manufacturer via SNS.

• Korean journal of communication and information
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• v.66
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• pp.59-86
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• 2014

This study explored how rumor is diffused via Twitter and how the characteristics of rumor affect the interactivity among users in the Korea-U.S. FTA case. A key word search located three issues as major ones related to the Korea-U.S. FTA: appendectomy myth, collapse of health insurance, and increases in medicine prices. The arousal of rumor has two dimensions: fact and expression. The fact arousal was the highest in the issue of 'appendectomy myth', and the expression arousal the highest in 'increases in medicine prices'. The rumor diffusion took the 'explosive wave' in the issue of appendectomy myth, the 'latent wave' in the issue of increase in medicine prices, and the 'repetitive wave' in the issue of collapse of health insurance. Correlation analyses revealed a high correlation between the arousal intensity of rumor and the user interactivity in the issue of collapse of health insurance. The study showed that Twitter took a role of diffusing negative messages about the Korea-U.S. FTA. Results implies that government officials and journalists pay attention to Twitter for sensing the public opinion when building policies and managing crises.

• ETRI Journal
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• v.31 no.2
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• pp.215-224
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• 2009

Analyzing the diffusion of a convergence product is a new and challenging research field. It is very difficult to find research dealing with this issue due to the inherent complexity and lack of data. In analyzing the diffusion of a convergence product, we should simultaneously take into account its relationship with related single-function products because of their similarities in terms of technology and functionality. In this study, we empirically analyze the diffusion of the convergence mobile phones in South Korea and find that the convergence products can affect the diffusion of MP3 players and digital cameras positively or negatively. This research may be significant for business strategies in technology management and product development.

• Journal of the Korea Society of Computer and Information
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• v.16 no.2
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• pp.165-172
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• 2011

Wireless sensor networks consist of small battery powered devices with limited energy resources. Once deployed, the small sensor nodes are usually inaccessible to the user, and thus replacement of the energy source is not feasible. Hence, energy efficiency is a key design issue that needs to be enhanced in order to improve the life span of the network. Directed Diffusion is a well known routing protocol. In this paper we adopt the clustering mechanism to improve the efficiency of Directed Diffusion. We introduce C-Directed Diffusion which make clusters, select the CH(Cluster Head) and CHs do the same process as in Directed Diffusion. C-Directed Diffusion is pretty simple and show better performance than Directed Diffusion.

• Journal of Information Processing Systems
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• v.18 no.1
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• pp.59-74
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• 2022

During the last decade, the security of digital images has received considerable attention in various multimedia transmission schemes. However, many current cryptosystems tend to adopt a single-layer permutation or diffusion algorithm, resulting in inadequate security. A hierarchical bilateral diffusion architecture for color image encryption is proposed in response to this issue, based on a hyperchaotic system and DNA sequence operation. Primarily, two hyperchaotic systems are adopted and combined with cipher matrixes generation algorithm to overcome exhaustive attacks. Further, the proposed architecture involves designing pixelpermutation, pixel-diffusion, and DNA (deoxyribonucleic acid) based block-diffusion algorithm, considering system security and transmission efficiency. The pixel-permutation aims to reduce the correlation of adjacent pixels and provide excellent initial conditions for subsequent diffusion procedures, while the diffusion architecture confuses the image matrix in a bilateral direction with ultra-low power consumption. The proposed system achieves preferable number of pixel change rate (NPCR) and unified average changing intensity (UACI) of 99.61% and 33.46%, and a lower encryption time of 3.30 seconds, which performs better than some current image encryption algorithms. The simulated results and security analysis demonstrate that the proposed mechanism can resist various potential attacks with comparatively low computational time consumption.

• Smart Media Journal
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• v.13 no.2
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• pp.9-15
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• 2024

In this paper, a Diffusion Multi-step Classifier (DMC) is proposed to address the imbalance issue in credit prediction. DMC utilizes a Diffusion Model to generate continuous numerical data from credit prediction data and creates categorical data through a Multi-step Classifier. Compared to other algorithms generating synthetic data, DMC produces data with a distribution more similar to real data. Using DMC, data that closely resemble actual data can be generated, outperforming other algorithms for data generation. When experiments were conducted using the generated data, the probability of predicting delinquencies increased by over 20%, and overall predictive accuracy improved by approximately 4%. These research findings are anticipated to significantly contribute to reducing delinquency rates and increasing profits when applied in actual financial institutions.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.694-699
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• 2000

Recently, the degradation of reinforced concrete structures due to physical and chemical attack has been a major issue in construction engineering. One of the main causes of degradation of concrete structures can be ascribed to chloride-induced corrosion, i.e., the rapid penetration of chloride ions into concrete. To estimate durability of reinforced concrete structures exposed to marine environment, many different kinds of accelerated tests to evaluate the concrete diffusivity were proposed. In this study, present test methods are reviewed and a proper test method for concrete is selected. The diffusion coefficients of concrete with corrosion inhibitor are measured using the proposed method, and then, measured values are compared to those of concrete without corrosion inhibitor. It is found from experimental results that diffusion coefficient re decreased with curing ages.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.5
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• pp.360-364
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• 2009

Analyzing information diffusion in a blog world is a very useful research issue, which can be used for predicting information diffusion, abnormally detection, marketing, and revitalizing the blog world. Existing studies on information diffusion in blog networks establish explicit relationship between blogs, and analyze only the word-of-mouth effect through such explicit relationships. However, we observed that more than 85% of all information diffusion in a blog world occurs through non-explicit relationships. In this paper, we propose a new model that considers both explicit and non-explicit relationships between blogs in order to explain all information diffusion phenomena in a blog world. We verify the superiority of our proposed models through extensive experiments of information diffusions at a real blog net-work.

• Journal of Electrochemical Science and Technology
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• v.14 no.4
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• pp.326-332
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• 2023

The high cost of Si-based solar cells remains a substantial challenge to their widespread adoption. To address this issue, it is essential to reduce the production cost of solar-grade Si, which is used as raw material. One approach to achieve this is Si electrodeposition in molten salts containing Si sources, such as SiO₂. In this study, we present the pulse electrodeposition of Si in molten CaCl₂ containing SiO₂ nanoparticles. Theoretically, SiO₂ nanoparticles with a diameter of less than 20 nm in molten CaCl₂ at 850℃ have a comparable diffusion coefficient with that of ions in aqueous solutions at room temperature. However, we observed a slower-than-expected diffusion of the SiO₂ nanoparticles, probably because of their tendency to aggregate in the molten CaCl₂. This led to the formation of a non-uniform Si film with low current efficiency during direct current electrodeposition. We overcome this issue using pulse electrodeposition, which enabled the facile supplementation of SiO₂ nanoparticles to the substrate. This approach produced a uniform and thick electrodeposited Si film. Our results demonstrate an efficient method for Si electrodeposition in molten CaCl₂ containing SiO₂ nanoparticles, which can contribute to a reduction in production cost of solar-grade Si.