• KIPS Transactions on Computer and Communication Systems
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• v.4 no.9
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• pp.307-314
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• 2015

Recently, market trends of auxiliary storage device HDD and SSD are interchangeable. In the future, the SSD is expected to be used more popular than HDD as an auxiliary storage device. The TRIM command technique has been proposed and used effectively due to the development of the SSD. The TRIM command techniques can be used to solve the problem of Freezing SSD that operating system cooperates with the SSD. The TRIM command techniques are performed in the idle time of the internal SSD that are actually deleted when a user deletes the data. However, in the point of view of computer forensics, the digital crime is increasing year by year due to lack of data recovery. Thus, this rate of arrest is insufficient. In this paper, I propose a solution that selectively manages data to delete based on advantage of the stability and the write speed of the TRIM command. Through experiments, It is verified by measuring the performance of the traditional method and selected method.

• Journal of The Korean Association of Information Education
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• v.11 no.1
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• pp.79-89
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• 2007

Considering the continuous increase of teenagers' Internet use and the high rate of their participation in online communities, educators need to devote efforts to minimize the negative function of teenagers' Internet use and to guide them to experience positive aspects of Internet. Through activities in online communities, teenagers can experience various socialities and explore their self-consciousness. However, on the other hand many communities do not provide teenagers with considerate care. This may cause conflict in their sense of value and mislead them. Through this study, online learning community is designed and developed, which can reflect teenagers' various needs and connect their needs with learning experiences. The community consists of the following categories: 'about e-Tivity'(community vision, general information, list of activities, Q&A), 'activity space for teens'(event hall, data park, e-Tivity center), 'administrative space for teachers and managers'(research room, management room), and 'teen's private space'(my room, my avatar).

• Journal of Digital Convergence
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• v.16 no.9
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• pp.133-145
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• 2018

This study was investigated the necessity and possibility of using block-chain technology in online used-goods trading platform. Current online used-goods trading platforms operate a safety trading system, but it is difficult to utilize due to relatively high commission rate. As a result, people mainly use the method of meeting and purchasing in person, which is a relatively costly method. This study discusses how to build a platform to solve or mitigate problems such as privacy, information distortion and omission, fraud, etc. In the platform proposed in this study, it is possible to solve the major fraud and personal information protection problems that may occur in the transaction proceeding by appropriately reflecting the types and characteristics of the block-chain technology. In future work, we will discuss legal framework and technology development plan to apply the proposed platform in this study.

• Journal of Digital Convergence
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• v.16 no.9
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• pp.465-475
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• 2018

This study aims to confirm whether both the emotional labour and job stress contribute to the turnover intention of infant teacher. The correlation analysis and parametric analysis were sequentially performed for our study. Analyzed results showed that the emotional labour was related to the job stress and turnover. Also, a statistical significance between the job stress and turnover intention was observed. Besides, the job stress partially mediated the relation between the emotional labour and turnover intention. Nsidering that the emotional labor of teacher caring or lived with infants occurred inevitably, our study proposed three approaches to reduce the job stress that partially mediated relation between the emotional labour and turnover intention. Generally, the infant teacher with excellent qualification produced the good education. Therefore, we suggested that the it was necessary that a work environment had been improved and working motivation was ameliorated to employ the infant teacher with excellent qualification.

• Journal of Digital Contents Society
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• v.16 no.4
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• pp.523-534
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• 2015

Social learning is a form to support learners' active engagement and participation in learning with other learners and instructors by using social media. The concept of social learning should be considered beyond the simple use of social media for learning or education. This study aims to apply the understanding of social learning based on the theoretical background of social theories of learning in designing and developing a program for workforce education. As a pilot test, the newly developed social learning program was implemented to 302 employees with the title of 'Innovative Display Strategy for POP". 138 employees successfully completed the social learning course that focuses on delivering contents in time-line based platform, supporting interactions among students, and working effectively through small smart devices in their workplace. The results were derived from three kinds of data-source: learner's log data, their final evaluation score, and the survey to measure the satisfaction about social learning. Finally the implications for social learning were discussed in terms of the program revision and directions for future application.

• Journal of Korea Port Economic Association
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• v.31 no.4
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• pp.189-207
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• 2015

The purpose of this study is to examine the relationship between the network characteristics of ports and their performance that is represented by port competitiveness for the port operators. The study employs Social Network Analysis (SNA) to evaluate network characteristics comprising four centrality indices. For this research, data from Containerization International Yearbooks for 2006-2011 is used to analyze the service networks of 20 major liner shipping companies. In SNA, nodes (vertices) in the network are the ports and links (edges) in the network are connections realized by vessel movements, such that the liner shipping network determines the port network. In addition, panel regression analysis has been employed to investigate the relationship between port network characteristics and their performance. The results suggest that the four centrality indices identify the roles of the world's major ports from 2006 to 2011 and that port performance is determined not only by macroeconomic variables and service capabilities but also by the eigenvector centrality of ports in networks.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.47-54
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• 2009

These clays, because of world economy recession, exports decreased rapidly and manufacturing industry growth fell into negative. Industrial power consumption has been reduced about 7[%] that forms 53[%] of total load demand in Korea. And also, daily load pattern has been changed in several ways because of power consumption decrease influenced by domestic demand recession and heating power load decreased by the rise in temperature. This research analyzes, by analyzing maximum load demand, average load demand, load pattern based on relative factor, and load sensitiveness in accordance with temperature, that maximum load demand is more sensitive to atmospheric temperature than GDP growth rate and average load demand tends to be reduced according to GDP growth rate. I suppose KPX could operate the network system economically and safely by forecasting load demand in winter and summer seasons based on the results.

• Journal of Korean Society of Transportation
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• v.23 no.8 s.86
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• pp.67-75
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• 2005

This study analyzed the relationships between expenditures on transportation and those on communications, using consumer expenditure data from the U.S. for the 19 years 1984-2002. We first identified 12 categories of goods for transportation and communications, and then applied the linear approximate Almost Ideal Demand System(LA/AIDS) method for estimating consumer demand functions based on aggregating the categories to five (public transportation, personal vehicle capital, personal vehicle operation, electronic communications media, and print communications media) due to the small sample size. Expenditure and price elasticities were also calculated at mean values of expenditure shares. The results indicate that transportation and communications categories have both substitutive(e.g. public transportation and electronic communications media) and complementary(e.g. private vehicle capital and electronic communications media) relationships. Additionally, expenditures in the transportation categories are generally more income-elastic than those in communications.

• International Journal of Highway Engineering
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• v.10 no.2
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• pp.135-143
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• 2008

According to the present highway design criteria, there are minimum standards which re ade from special design speeds. If some highways are satisfied the standards, it regards he highway as safety. In reality, however, most drivers drive a car at different speed compared with design speed. It is very dangerous for drivers especially at transition sections between curve and horizontal curve sections. Hence, this study calculated the rate of changing and horizontal acceleration at each section. Moreover, this study evaluated thesafety of design at curve transition sections and then calculated lateral acceleration and curve radii. This study found the minimum standards which are using as basic safety standards are not appropriate for measuring driver's safety.

• Journal of Korea Water Resources Association
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• v.33 no.6
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• pp.765-774
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• 2000

The purpose of this study are to develop a realistic methodology to estimate agricultural water supply for rice paddy fields from reservoirs, pumping stations, intake structures, and tube wells on river basin scale. Agricultural water supply from irrigation reservoirs are estimated using the daily or ten day's storage rate data and DIROMmaily Inigation Reservoir Operation Model) model. Estimation of daily water supply from pumping station are carried out from the annual water use with typical water supply patterns. The daily groundwater withdrawn are investigated from the gross water requirement for rice and the design capacity of tube well. And, the daily intake discharge are estimated the minimum amount from the gross water requirement, stream discharge, and the design capacity. During 1993 to 1997, the annual water supply for irrigation in the Han river basin ranged from 569 to 709 million $\textrm{m}^3/yr$, and the mean was estimated to be 640 million $\textrm{m}^3/yr$.