• Journal of Korea Technology Innovation Society
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• v.7 no.1
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• pp.89-110
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• 2004

Home networks consist of two or more home appliances or communication devices enabling the mutual data communication between appliances such as personal computers, refrigerators, phones, television sets, personal digital assistants(PDA), etc. There are three factors that create demand for the home network services. The first factor is development of technology. Second, on the demand side, consumer demand for the home appliances having access to the Internet is in the increase. Finally, producers need a strategy to deal with the problem of market saturation. Home networks are emerging markets. They are unique in that they unite information technologies with home appliances that provide new services. in this paper we study the main attributes of home network services and analyze consumers' preferences for them. However, it is not quite possible to use the revealed preference approach since the home network market is still at an incipient stage. We therefore use the conjoint analysis method using stated preference data. conjoint analysis has been widely use in the area of marketing for evaluating consumer preferences for new products and services. it presents a hypothetical product to the respondents along with the product's attributes and their levels. The respondents are asked to either rank each alternative or choose between several hypothetical products. By estimating consumers' willingness to pay for the attributes of the home network services and analyzing consumers' preferences, we predict the pattern of the development of the home network services and related technologies along various quality dimensions. Based on the estimation results, we draw policy implications for the national- and company-level strategy.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.16 no.6
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• pp.95-109
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• 2006

Elliptic Curve Cryptosystem (ECC) is suitable for resource-constrained devices such as smartcards, and sensor motes because of its short key size. This paper presents an efficient multi-scalar multiplication algorithm which is the main component of the verification procedure in Elliptic Curve Digital Signature Algorithm (ECDSA). The proposed algorithm can make use of a precomputed table of variable size and provides an optimal efficiency for that precomputed table. Furthermore, the given scalar is receded on-the-fly so that it can be merged with the main multiplication procedure. This can achieve more savings on memory than other receding algorithms. Through experiments, we have found that the optimal sizes of precomputed tables are 7 and 15 when uP+vQ is computed for u, v of 163 bits and 233 bits integers. This is shown by comparing the computation time taken by the proposed algorithm and other existing algorithms.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.15 no.2
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• pp.695-712
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• 2021

As the use of smart devices is being increased rapidly by the development of internet and IT technology, the contents production and utilization rate are showing higher increase, too. In addition, the type of contents also shows very diverse forms such as education, game, video, UCC, etc. In the meantime, the contents are reproduced in diverse forms by reprocessing the original contents, and they are being serviced through the contents service platform. Therefore, the platform to make the contents reprocessing easy and fast is needed. As the diverse contents distribution channels such as YouTube, SNS, App Service, etc, easier contents distribution platform is needed, and the development of the relevant area is expected. In addition, as the selective consumption of the contents having easy accessibility through diverse smart devices is distinguished, the demand for the platform and service that can identify the contents consumption propensity by individual is being increased. Therefore, in this study, to vitalize the online contents distribution, the contents reproduction and publishing platform, was designed and materialized, which can reproduce and distribute the contents based on the real-time contents editing technology in URL unit and the consumer propensity analysis technology using the data management-based broadcasting contents distribution metadata technology and the edited image contents streaming technology. In addition, in the results of comparing with other platforms through the experiment, the performance superiority of the suggested platform was verified. If the suggested platform is applied to the areas of education, broadcasting, press, etc, the multi-media contents can be reproduced and distributed easily, through which the vitalization of contents-related industry is expected.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.2
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• pp.89-94
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• 2011

Today, the utilization of communication devices is being increased including information terminals, cell phones, handheld personal digital assistants (PDA) caused by the development of information and communication technology. The development of information and services is speeding up, whereas most communication devices have provided a inefficient hierarchical menu and sequential searching structure. In this study, the Adaptive User Interface is applied to the Bus Information Terminal(BIT) which is one of communication equipment installed in the bus stop. It will be based on analysis of unspecified individuals' preferences and user's directly personalization in the BIT prototype. We expect the results of this study to be possible to provide users with efficient and convenient information acquisition and contribute to the development of public transport use by improving the accessibility and usability of BIT.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.28 no.3
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• pp.625-633
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• 2018

Realm is an open source database developed to replace SQLite, which is commonly used in mobile devices. The data stored in the database must be checked during the digital forensic analysis process for mobile devices because it can help to understand the behavior of the user and whether the mobile device is operating or not. In addition, since the user can intentionally use anti-forensic techniques such as deleting data stored in the database, research on how to recover deleted records is needed. In this paper, we propose a method to recover records that have not been overwritten after deletion based on the analysis of the structure and record and deletion process of the Realm database file.

• Journal of the Korea Society of Computer and Information
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• v.11 no.2 s.40
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• pp.145-151
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• 2006

In conjunction with the rapid progress of IT(information technology) an increasing amount of data are being generated. The amount of new data is so big and the type of new data generated from clients or sensor devices needed to be in ubiquitous environment is so various that it is hard to manage and control them. Especially data to be occurred in ubiquitous environment are generated through PDA(personal digital assistant) smart phone, mobile device or sensor units etc. Therefore, to manage and control them generated from ubiquitous devices for decision making, we can use data warehouse as an integrated storage. A data warehouse integrates and aggregates data of several different DBMS into one DBMS. Also the updated data from source data have to be effectively propagated to the data warehouse. Therefore, in this paper, we proposed a mode) for an exact and efficient data management methodology in new IT paradigm environment, ubiquitous computing environment, to apply updated data on the warehouse to make decision. We also show brief result compared to conventional methodology.

• Journal of Korean Elementary Science Education
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• v.41 no.3
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• pp.480-500
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• 2022

In this study, the perception and demands on the use of realistic content were analyzed through in-depth interviews with elementary school teachers experienced in using realistic content in science classes. Specifically, the following questions were investigated: (1) What kind of realistic content and how do elementary school teachers use it in science classes? (2) What are the perceptions and difficulties of elementary school teachers regarding the use of realistic content in science classes? (3) What are the needs of elementary school teachers related to the professional development program for the use of realistic content in science classes? The study revealed the following results. First, elementary school teachers mainly used digital textbooks and realistic content provided by the "Science Level Up" site, and the content types could be classified into "exploration type," "visit type," and "production type," according to the purpose of use. Second, elementary school teachers mentioned the educational advantages of using realistic content to help students understand scientific content, induce interest and curiosity, and become immersed in a sense of reality. Several difficulties related to the use of realistic content were mentioned. Among them, the lack of high-quality educational content suitable for science classes and a lack of examples of specific class cases that use realistic content stood out. Thirdly, regarding the development of teacher expertise to use realistic content, elementary school teachers emphasized the need for information on quality realistic content; teacher training centered on specific class cases; instructional models that can be applied by realistic content type; and information on the purchase, use, management, and operation of necessary devices. Reflecting on these research results, implications for more effective use of realistic content in elementary science classes were discussed.

• Journal of Korea Multimedia Society
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• v.16 no.12
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• pp.1495-1507
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• 2013

Smart device appeared as IT technology develops and it caused the proliferation of digital contents. It is because that App technology supports to install and use the contents in the smart device easily. App is developed by the creativity and the programming skill and the commercial value is generated in the process of development. In this paper, we taught how to develop APP to elementary school students by Android App Inventor program and observed the changes of their thinking through reflection-note which describes thinking of them. This research was carried out for 28 elementary school students, 5th and 6th grade. We found the attitude that students try to solve problem actively with the high interest. They enjoy showing developed App to others easily and quickly, which is the characteristic of smart devices. We also found a phenomenon that the students consider commercial value.

• The Journal of the Korea Contents Association
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• v.19 no.11
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• pp.270-277
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• 2019

These days, with the advent of digital broadcasting, media environment offers users an opportunity to enjoy differentiated contents in a more aggressive fashion through user-media interactions based on computer technology. In fact, the development of contents which can induce spontaneous acts from users such as outdoor ads which use certain sensors and devices and exhibition halls has been active. With the development of low-price motion recognition devices, people have been able to enjoy diverse interaction-applied media by recognizing users' motion data without body contact. In this paper, we developed an interactive media player that can recognize the user's motion and control the video in the web service environment without installing a specific program. In addition, we set user motion recognition range and developed a user motion recognition algorithm suitable for the Leap Motion equipment installed in the kiosk. The results of this study can be experienced by various interactive media such as interactive tourism, education, and movie contents in kiosks that can be installed in public places.

• The KIPS Transactions:PartA
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• v.17A no.2
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• pp.63-72
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• 2010

Recently, the need for multimedia devices, such as digital TV, and camcorder has increased. These devices provide many services on multimedia files such as playing, recording, and editing. Throughout these services, in case of storing edited large-scaled multimedia files, existing file system have several capability problems that are taking too much time and requiring disk I/O. In this paper, we propose the use of Linux Ext2 file system based 'Block-Link file (BL-file) system' in order to solve these problems. For the BL-file system, when editing and storing large-scaled files, there is no data input or output but only modification of the metadata. Additionally, by sharing data blocks between multimedia files, we can save disk spaces. Moreover, because the managing of data block sharing information is more convenient than the existing FWAE technique, we can lessen system overhead. The BL-file system is based on Ext2 file system and implemented in a Linux environment, and the usefulness of the proposed technique is validated by applying the Linux multimedia file-editing tool 'Avidemux'.