• Journal of the Korea Institute of Information and Communication Engineering
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• v.22 no.10
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• pp.1320-1326
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• 2018

Digital video equipment is important in the 4th industrial revolution and is widely used in different fields for various purpose. Data of digital video equipment is exposed to noise due to different reasons including user environment and processing and such noise affect output and processing method. This can even cause error, resulting in decreased reliability of the equipment. In this research, it offers algorithm to effectively recover video by removing noise and impulse noise occurring during the process of channel delivery. This proposed algorithm recovers video by exploring valid pixel using directional local mask and noise determination. Then, valid pixel calculated goes through the final output calculation through comparative analysis on estimation. For comparing suggested method and algorithm, simulation is carried out. For checking the function of it, PSNR and profile are analyzed.

• The KIPS Transactions:PartD
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• v.16D no.5
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• pp.683-690
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• 2009

Social Networks which is composed of network with an individual in the center in a web support mutual-understanding of information by searching user profile and forming new link. Therefore, if we apply the Social Network which consists of web users who have similar immanent information to web search, we can improve efficiency of web search and satisfaction of web user about search results. In this paper, first, we make a Social Network using web users linked directly or indirectly. Next, we calculate Similarity among web users using their immanent information according to topics, and then reconstruct Social Network based on varying Similarity according to topics. Last, we compare Similarity with Search Pattern. As a result of this test, we can confirm a result that among users who have high relationship index, that is, who have strong link strength according to personal attributes have similar search pattern. If such fact is applied to search algorithm, it can be possible to improve search efficiency and reliability in personalized and social search.

• KIPS Transactions on Computer and Communication Systems
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• v.7 no.10
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• pp.251-258
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• 2018

Ransomware, a malicious software that requires a ransom by encrypting a file, is becoming more threatening with its rapid propagation and intelligence. Rapid detection and risk analysis are required, but real-time analysis and reporting are lacking. In this paper, we propose a ransomware infection detection system using social big data mining technology to enable real-time analysis. The system analyzes the twitter stream in real time and crawls tweets with keywords related to ransomware. It also extracts keywords related to ransomware by crawling the news server through the news feed parser and extracts news or statistical data on the servers of the security company or search engine. The collected data is analyzed by data mining algorithms. By comparing the number of related tweets, google trends (statistical information), and articles related wannacry and locky ransomware infection spreading in 2017, we show that our system has the possibility of ransomware infection detection using tweets. Moreover, the performance of proposed system is shown through entropy and chi-square analysis.

• Journal of Intelligence and Information Systems
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• v.11 no.2
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• pp.17-29
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• 2005

The purpose of the study was to explore the potential of the Social Network Analysis as an analytical tool for scientific investigation of learner-learner, or learner-tutor interaction within a Computer Supported Corporative Learning (CSCL) environment. Theoretical and methodological implication of the Social Network Analysis had been discussed. Following theoretical analysis, an exploratory empirical study was conducted to test statistical correlation between traditional performance measures such as achievement and team contribution index, and the centrality measure, one of the many quantitative measures the Social Network Analysis provides. Results indicate the centrality measure was correlated with the higher order teaming performance and the peer-evaluated contribution indices. An interpretation of the results and their implication to instructional design theory and practices were provided along with some suggestions for future research.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.8
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• pp.1535-1543
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• 2007

Recently, there are many researches for P2P network. P2P network technologies are a good solution about making a wide spread distributed computing in the internet environment. The recent algorithms developed by several research groups for the lookup problem present a simple and general interface, a distributed hash table (DHT). In this paper, we also introduce new schemes that enhance the available rate of an object in the MagicSquare network. Replication scheme is to replicate an object with many replicas and save them to several nodes. Fragmentation scheme is to divide an object into several fragments and save them to several nodes. Replicated Fragmentation scheme is to mix replication scheme and fragmentation scheme. We will show result of simulation for our the proposed scheme.

• Korean Journal of Comparative Education
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• v.28 no.5
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• pp.1-19
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• 2018

The purpose of educational assessments such as the Trends in International Mathematics and Science Study (TIMSS) is to compare groups such as countries. When the unit of measurement is above the student level, group-level diagnostic assessment based on multilevel item response theory (ML-IRT) can be considered just as cognitive diagnosis models are developed from item response theory. This study suggests an ML-IRT-based group-level diagnostic assessment model by modifying an item feature model by Park and bolt (2008). The model is illustrated on the recently released TIMSS 2015 Grade 8 mathematics assessment. The results provide skill profiles for the studied countries and the nine cognitive attributes; that is, the attribute effects can be compared across the countries and also across the attributes. By controlling unexplained variance, the suggested model may provide more reliable and more informative group-level comparisons. The results are interpreted using an example. Limitations and directions for future research are also discussed.

• The Journal of the Korea Contents Association
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• v.19 no.7
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• pp.149-165
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• 2019

The purpose of this study is to conduct an in-depth interview on 5 middle aged women who have attempted suicide in the past and to explore their suicide attempts and the vivid empirical value of life after the attempt. The collected data were analyzed using Giorgi's phenomenological approach. The data analysis resulted in 21 sub categories and 7 essential categories. Study participants experienced an-'selected death at the end of a cliff', 'standing on the border of life and death', 'life became clear after escaping delusion', 'working toward life once again', 're-evaluating their past life and discovering new possibilities', 'experiencing the vividness of life here', 'spiritual growth and deeper insight'. Such results offer a discussion on existence toward self-completion, and hold significance in that it increased our in depth understanding and recognition beyond the narrow perceptions of individuals who attempt suicide.

• Asia-pacific Journal of Multimedia Services Convergent with Art, Humanities, and Sociology
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• v.9 no.9
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• pp.797-808
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• 2019

The purpose of this study is to collect the psychological responses that occur while watching TV home shopping ads in verbal form, and explore the possibility of measuring the effectiveness of TV home shopping ads using linguistic analysis. The psychological responses during watching positive and negative ads of participants(40 housewives and female college students) were collected in a linguistic form using a think aloud and self-report measurement. It was analyzed by KLIWC, a Korean language analysis program. As a result of the analysis, there was a difference in psychosocial variables as well as linguistic variables between positive and negative evaluation ads. Also, various variables of KLIWC were correlated with the variables of advertising effectiveness (purchase stimulus, ad attitude, product attitude, purchase intention) and advertising response variables. This suggests the possibility of constructing a psychological response profile and measurement of advertising effectiveness using language analysis.

• Applied Chemistry for Engineering
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• v.34 no.5
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• pp.488-492
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• 2023

In this study, a carbon film derived from a polymer/lignin composite precursor was produced by a carbonization cycle with a controlled temperature profile. The feasibility of successful formation of the carbon film using the carbonization cycle was monitored. The adsorption behavior of the carbon film toward various molecules, such as nonpolar and polar organic molecules, and dyes was investigated using ultraviolet/visible (UV/Vis) spectroscopy compared with that of carbonized lignin. Cyclic voltammetry (CV) analysis proved that a robust carbon film was prepared by the carbonization cycle. It was also demonstrated that the carbonized lignin and carbon film showed adsorption capability toward all types of organic molecules, in particular organic dyes, owing to the carbonized lignin. This work provides important information for future relevant research.

• 대한공업교육학회지
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• v.32 no.1
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• pp.134-152
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• 2007

This study deals with the development of computer program which can restrict students to access to the unallowable web sites during the Internet based class. Our suggested program can find the student's access list to the unallowable sites, display it on the teacher's computer screen. Through the limitation of the student's access, teacher can enhance the efficiency of class and fulfill his educational purpose for the class. The use of our results leads to the effective and safe utilization of the Internet as the teaching tools in the class. Meanwhile, the typical method is to turn off the LAN (Local Area Network) power in order to limit the student's access to the unallowable web sites. Our program has been developed on the Linux operating systems in the small network environment. The program includes following five functions: the translation function to change the domain name into the IP(Internet Protocol) address, the search function to find the active students' computers, the packet snoop to capture the ongoing packets and investigate their contents, the comparison function to compare the captured packet contents with the predefined access restriction IP address list, and the restriction function to limit the network access when the destination IP address is equal to the IP address in the access restriction list. Our program can capture all passing packets through the computer laboratory in real time and exactly. In addition, it provides teacher's computer screen with the all relation information of students' access to the unallowable sites. Thus, teacher can limit the student's unallowable access immediately. The proposed program can be applied to the small network of the elementary, junior and senior high school. Our research results make a contribution toward the effective class management and the efficient computer laboratory management. The related researches provides teacher with the packet observation and the access limitation for only one host, but our suggested program provides teacher with those for all active hosts.