• Journal of Korea Multimedia Society
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• v.8 no.8
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• pp.1142-1151
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• 2005

Various kinds of studies for building up U-Korea are now underway. Especially, RFID comes into the spotlight as a core technology of Ubiquitous. Though, the development of higher levels of application is far behind the hardware-based technology in RFID application system. For that reason, In this paper suggests technology using RFID on Ubiquitous and embodies the effective health care application which is one of the application services of user-centered environment It realizes the system which enables us to manage and send data about changing prescriptions and locations of patients effectively under the basis of RFID tag and mobile devices. It also provides the high quality of practical effectiveness of entire system throughout the realization of applications of application server and mobile device. on the basis of framework for providing the various kinds of services and physical elements.

• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1153-1162
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• 2005

In this paper, we developed an XML Document Data Synchronization System for java(XDS4j) based on both SyncML(Synchronization Markup Language) framework Sync4j and embedded database system Berkeley DB XML. Because most existing data synchronization systems are based on file systems, data synchronization times at Fast Sync in those systems are very delayed. In the XDS4j, however, XML documents data produced at SyncML client and SyncML server are managed by embedded database system, and also synchronization time at Fast Sync is reduced because only partial elements are accessed by applying to XPath.

• Journal of Korea Multimedia Society
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• v.5 no.5
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• pp.530-537
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• 2002

Although a type of Web-based education has increased continuously, it has provided an environment that students use textbooks which are forms of homepage, make a note of lecture on Web browser, save the contents of note and use them again. Therefore, this thesis proposes a web note, MyNote, that students draw lines and write notes about the lecture using VML and DHTML on Web. Here, the contents of the note are saved in database with a form of text-based VML made dynamically using ASP. The document used with teaching material is downloaded from Web server to Web client and the content of VML is done from database. Using MyNote, students have their own libraries on Web. The content of note Is saved and printed on Web, and learners can relearn because they can review the content.

• Journal of Korea Multimedia Society
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• v.3 no.6
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• pp.661-673
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• 2000

In this paper, we propose a Web-based HW/SW Codesign Environment with Distributed Architecture (WebCEDA), then design and implement SpecCharts Specification Environment(ScSE) for specifying systems in WebCEDA. WebCEDA has 3-tier client/server architecture than can remedy disadvantages of existing codesign tools, such as platform dependency, difficulty of extension, absence of collaboraton environment. ScSE includes web interface, SpecCharts editor, HW/SW codesin application sever and SpecCharts translator. To verify the operation of ScSE, we specify several example system using SpecCharts editor, then translate it to VHDL using SpecCharts translator and simulate the translated VHDL codes on synopsys. As the results, we know that ScSE has correct operations, also obtain the following advantages, the reduction in system complexity and the natural abstract design.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.922-933
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• 2004

In recent years, peer-to-peer network have a greate deal of attention for distributed computing or collaborative application, and work of ID-based public key systems have been focusing on the area of cryptography. In this paper, we propose ID-based group key management protocols for secure communication in autonomous peer group. Each member obtains his public/private key pair derived from his identification string from Private Key Generator. No central server participates in group key management protocol instead, all group members share the burden of group key management by the collaboration of themselves, so that our scheme avoids the single point of failure problem. In addition, our scheme considers the nature of dynamic peer group such as frequent joining and leaving of a member.

• Journal of Korea Multimedia Society
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• v.4 no.6
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• pp.534-542
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• 2001

Recent content-based image retrieval systems make use of a local single server contained a limited number of images. So these systems are not satisfactory for the Web user's needs that make request for various images on the Web. A content-based image retrieval system that has regard for a great number of Web images has to stand on the basis of real-time first of all. Therefore, to implement the above system we have to resolve a problem of large waste time to take for an image collection and feature extractions. In recent, PC clusters with a load distribution are implemented for the purpose of high-performance data processing. In this paper, we decreased the whole retrieval time by distributing the tasks of image collection and feature extraction to take much time among the slave computers of the PC cluster, and so we found the possibility of the real-time processing in the retrieval of Web images.

• Journal of Korea Multimedia Society
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• v.9 no.2
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• pp.208-214
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• 2006

Participants of a NVE(networked virtual environment) may have different hardwares and network environments, and to guarantee the fairness, messages of participants should be synchronized. A solution for the synchronization problem is to wait for a certain amount of time until the server processes the message. It is not easy to determine a suitable waiting period because of the trade-off between the fairness and the responsiveness. In this paper we propose a method to decide a waiting period by considering only the participants with small network delays and perform experiments for the performance evaluation. Experiments show that the proposed method leads to significant improvement of responsiveness, while retaining fairness.

• Journal of Korea Multimedia Society
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• v.19 no.4
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• pp.689-705
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• 2016

This paper proposed an realtime total monitoring platform for various kind of multi weather radars to analyze and predict weather phenomenons and prevent meteorological disasters. Our platform is designed to process each weather radar data on each radar site to minimize overloads from conversion and transmission of large volumed radar data, and to set observers up the definitive radar data via public framework server separately. By proposed method, weather radar data having different spatial or temporal resolutions can be automatically synchronized with there own spatio-temporal domains on public GIS platform having only one spatio-temporal criterion. Simulation result shows that our method facilitates the realtime weather monitoring from weather radars having various spatio-temporal resolutions without other data synchronization or assimilation processes. Moreover, since this platform doesn't require some additional computer equipments or high-technical mechanisms it has economic efficiency for it's systemic constructions.

• Journal of Korea Multimedia Society
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• v.21 no.3
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• pp.415-422
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• 2018

Advances of telecommunication technology bring various changes in journalism field. Reporters started to gather, edit, and transmit content to main server in media company using hand-held smart media and notebook computer. This paper tried to testify valid bit-rate of visual news content using LTE network and mobile phone. Field news like natural disasters need real-time transmission of video content. But broadcasting company normally use heavy ENG system and transmission satellite trucks. We prepared and experimented different types of visual content that has different bit-rates. Transmission tool was LU-60HD mobile system of LiveU Corporation. Transmission result shows that bit-rate of 2Mbps news content is not suitable for broadcasting and VBR (Variable Bit Rate) transmission has better definition quality than CBR (Constant Bit Rate) method. Three different bit-rate of VBR transmission result shows that 5Mbps clip has better quality than 1Mbps and 3Mbps. The higher bit-rate, the better video quality. But if the content has much movements, that cause delay and abnormal quality of video. So optimizing the balance between stability of signal and quality of bit-rate is crucial factor of real-time broadcasting news gathering business.

• Journal of Korea Multimedia Society
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• v.20 no.4
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• pp.649-659
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• 2017

Typically, a smart car is equipped with access to the Internet and a wireless local area network. Moreover, a smart car is equipped with a global positioning system (GPS) based navigation system that presents a map to a user for recommending the shortest path to a desired destination. This paper presents the design and implementation of a real-time shortest path search system for directed and dynamic roads. Herein, we attempt to simulate real-world road environments, while considering changes in the ratio of directed roads and in road conditions, such as traffic accidents and congestions. Further, we analyze the effect of the ratio of directed roads and road conditions on the communication cost between the server and vehicles and the arrival times of vehicles. In this study, we compare and analyze distance-based shortest path algorithms and driving time-based shortest path algorithms while varying the number of vehicles to search for the shortest path, road conditions, and ratio of directed roads.