• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.4
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• pp.803-809
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• 2011

In this paper, we present a very useful method for updating digital satellite radio broadcast channel information. When a devices equipped with function to receive Digital Satellite Radio such as Home Theater, MP3 player, mobile phones, car audio system and various other types of Digital Devices, receives new Digital satellite radio (will be mentioned as XM radio onwards) broadcast channel information, only the current received XM radio broadcast channel and N number of pre/post nearby broadcast channels are scanned randomly in zigzag manner. Then the previous XM radio broadcast channel information updated with the newly received XM radio broadcast channel information. Since this method can prevent batch update for all XM radio channel, including some channels which less likely did not select by user, update process for real time frequently changed XM radio broadcast channel information can be performed efficiently with minimal or without delay.

• The KIPS Transactions:PartD
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• v.10D no.4
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• pp.639-646
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• 2003

Conventional two-tier databases have shown performance limitation in the presence of many concurrent clients. To this end, the three-tier architecture that exploits similarities in client's object access behavior has been proposed. In this system, clients are partitioned into clusters, and object requests can be then served in inter-cluster manner. Introducing an intermediate layer between server(s) and clients enables this. In this paper, we introduce the problem of client realignment in which access behavior changes, and propose on-line client clustering. This system facilitates adaptive reconfiguration and redistribution of sites. The core issue in this paper is to demonstrate the effectiveness of on-line client clustering. We experimentally investigate the performance of the scheme and necessary costs.

• The KIPS Transactions:PartC
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• v.15C no.6
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• pp.469-480
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• 2008

The recently proposed RFID(Radio Frequency Identification) authentication protocol based on a hash function can be divided into two types according to the type of information used for authentication between a reader and a tag: either a value fixed or one updated dynamically in a tag memory. In this paper, we classify the protocols into a static ID-based and a dynamic-ID based protocol and then analyze their respective strengths and weaknesses. Also, we define a new security model including forward/backward traceability, synchronization, forgery attacks. Based on the model, we analyze the previous protocols and propose a new dynamic-ID based RFID mutual authentication protocol. Our protocol provide enhanced RFID user privacy compared to previous protocols and identify a tag efficiently in terms of the operation quantity of a tag and database.

• The Journal of the Korea Contents Association
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• v.14 no.1
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• pp.150-157
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• 2014

This thesis intends to grasp the degree of utilization of visual images by understanding the relational properties between picture and letter and considering the children as users, through the analysis of currently published books of English vocabulary for children. Accordingly, the types of picture used in the books of English vocabulary for children, the degree of utilization of picture, combination types of picture and letter, and semantic consistency of picture and letter are reviewed. As a result of analysis, the degree of utilization of picture is high in general, in order of illustration, cartoon, and the mix of illustration and cartoon. In the combination form of picture and letter, the degree of utilization appears in order of picture plus vocabulary, letters without illustration, and pictorial symbol. In particular, the higher semantic consistency of picture and letter, it is effective in learning, however, semantic consistency is low, generally. Pictorial symbol type shows the frequency of the highest combination type in the five groups of higher semantic consistency. In conclusion, the presented types of picture and letter, shown in the currently published books of English vocabulary for children, are similar types by the publishing companies, thus, effective design research should be required based on diverse levels of children.

• Archives of design research
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• v.16 no.2
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• pp.271-280
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• 2003

In digital age, multimedia technology has changed the learning method as a learner-directed way. CD-rom and internet that are major two multimedia learning way, has aimed at edutainment which combine education and entertainment. However, existing educational contents can only induce temporary learning motivation, and are in short of entertaining factors enough to induce continuous and ingenuous learning motivation. Therefore, in order to be used by users efficiently, educational software have to adapt characteristics of educational game more actively. In this paper, adoption method of characteristics of educational game in learning contents is sought and the specific example of adoption is demonstrated by a case study of developing vocabulary learning educational game.

• The Journal of the Korea Contents Association
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• v.17 no.7
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• pp.1-11
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• 2017

The best business strategy leading to innovation and productivity can be achieved by carefully analyzing internal and external environments of a company. Many companies often require, but difficult to find a tool to determine their own internal/external environmental factors including strengths, weaknesses, opportunities and threats(SWOT). SWOT is one analytical base model that is utilized in this research to design semi-automated environmental analysis process. This study investigates on SWOT generation system that is built on existing analysis database created by experts in each field. Companies can search and choose their best expressing environmental elements that are stored in the database. This semi-automated SWOT tool is expected to contribute that companies can recognize their internal capabilities more accurately, and help consider external environment changes around them.

• Journal of the Korean Institute of Gas
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• v.12 no.4
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• pp.29-33
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• 2008

The focus of this study is to develop a virtual reality program for safe training and virtual reality of hydrogen station. This programme consists of 4 modules such as hydrogen and safety module, hydrogen station module, hypothetical experience module, and accident scenarios module for hydrogen experts. User can experience with principles and operation condition and collect the information of hydrogen station by this programme and can simultaneously study the probable scenarios, emergency response plan/standard operating procedure about hydrogen stations. It makes it possible to educate and safety publicity for the trainee. This virtual reality program will be expected to be helpful for hydrogen station's construction propagation and technology development which is essential for hydrogen energy induction.

• Journal of KIISE
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• v.44 no.6
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• pp.613-620
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• 2017

Skyline queries are used extensively to solve various problems, such as in decision-making, because they find data that meet a variety of user criteria. Recent research has focused on skyline queries by using the MapReduce framework for large database processing, mainly in terms of applying existing index structures to MapReduce. In a skyline, data closer to the origin dominate more area. However, the existing index structure does not reflect such characteristics of the skyline. In this paper, we propose a grid-block structure that groups grid cells to match the characteristics of a skyline, and a two-level grid-block structure that can be used even when there are no data close to the origin. We also propose an efficient skyline-query algorithm that uses the two-level grid-block structure.

• The Journal of the Korea Contents Association
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• v.9 no.8
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• pp.32-40
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• 2009

This research provides a new approach for implementing an educational content for Historic Education in order to provide an effective learning environment. From historic educational point of view, it is important to comprehend a historical fact in the context of the situation at that time. So, this paper suggests that the historic content should describe not only information about various relics and ruins but also historical relationship and background. In this system, we provide versatile type of contents to help learners for collecting manifold informations about their interesting era. And this system proffers natural and residential 3D environments, which give learners to understand conceivably and to think collectively. Using the interactions, the learners navigating this virtual world are able to construct their own information system through selecting a interested one among the offered contents in the system and consequently they are getting a scientific thinking power and a creative imagination.

• The Journal of the Korea Contents Association
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• v.9 no.1
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• pp.475-483
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• 2009

With the development of information communication and network technologies, ubiquitous era that supports various services regardless of places and time has been advancing. The development of such technologies have a great influence on educational environments. As a result, e-learning concepts that learners use learning contents in anywhere and anytime have been proposed. The various learning contents authoring systems that consider the e-learning environments have also been developed. However, since most of the existing authoring systems support only PC environments, they is not suitable for various ubiquitous mobile devices. In this paper, we design and implement a contents authoring system based on learning activities for u-learning environments. Our authoring system significantly improves the efficiency for authoring contents and supports various ubiquitous devices as well as PCs.