• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3495-3501
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• 2010

Because the application simultaneously to transmit large amounts of data (Video conferencing, Internet broadcasting, Online games etc.) to multiple users increases, the importance and utilization of group communication was greater. So the security was recognized as a important issue. To provide security in multicast environment, A study of single group management server using protocol based on Key Tree Scheme was proposed. But the paper proposes secure group key management scheme to be a relatively low-overhead. Therefore proposed paper is demonstrated to be excellent by comparing the effectiveness of existing and proposed group key management scheme.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.2 no.1
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• pp.59-66
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• 2001

Networked Virtual Reality systems provide a consistent virtual world to the users, possibly ditributed across long distance, and have been widely applied in the military war game, network game. edutainment, architectural areas, and shopping mall etc. Large processing requirements. however. made these systems be mainly researched on the platforms of high-performence system graphics workstations. This study paper Presents several problems when networked virtual reality systems are implemented on commodity Internet : two problems related with 3D graphical Processing, and the other related with network bandwidth and transmission delay. We also suggest solutions to these problems and analyze their performance effect based on an architectural simulation application.

• Journal of Convergence Society for SMB
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• v.5 no.3
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• pp.21-26
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• 2015

As mobile contents grow up, In App Billing is brisk at applications including mobile contents. But some of users don't pay and use charged content for free to use cheating payment module or hacking through applications. Call this bypass payment. Applications, helping bypass, are Freedom, IAP Cracker, and DNS server suggested by the hacker named Borodin. In case of mobile game, Despite sell a lot of charged content but income is different revenue in sales log with real profits. Because of users using bypass payment application. Management plan to bypass payment are checking OrderID, encrypting public key and verifying receipt.

• Proceedings of the Korea Contents Association Conference
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• 2004.05a
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• pp.385-391
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• 2004

Today, mobile technology is developing very fast and people use internet through mobile phones. Using mobile phones, people use games, email, avatar and other services. We designed client/server modules in order to join email and avatar together. First two major server modules were designed, one of them is DB management module for avatar user information and the other is email management module. One the client side, we designed avatar image animation module and a module for showing the email contents. The purpose of the design is to reduce the performance overhead on the client side as mobile phones cannot be used as a high performance device. We propose and implement a new avatar based service using the SK-VM environment, that is different from the current avatar services.

• Journal of Korea Multimedia Society
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• v.17 no.4
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• pp.526-534
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• 2014

Most of the multiplayer games available online are based on a client-server architecture because this architecture gives better administration control to the game providers than peer-to-peer architecture. In this architecture, the server is responsible for all the communication between the connected clients. The weakness of this architecture is its bandwidth requirement and scalability. Peer-to-peer architectures have then been proposed to solve these issues. In this paper, we propose a hybrid client-server architecture in which the game state is partially shared by the mobile terminal to achieve consistency among different players. Like a peer-to-peer architecture, this architecture uses client-side capacities to reduce bandwidth requirements for the server and improves consistency in wireless networks. Client events have different timeliness and consistency requirements according to their nature in the game world. These requirements lead to tasks with different priorities on CPU processing. In the proposed architecture, either the server or the client applies consistency mechanism according to the priority level. Simulation experiments show that the bandwidth of the server in this architecture is smaller than that of the client-server architecture. As a result, the server in the proposed architecture can accommodate more clients with enhancing the scalability.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2006.11a
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• pp.269-272
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• 2006

홈 엔터테인먼트 서비스는 홈 네트워크 서비스의 하나로서 홈 네트워크를 통해 제공되는 TV, 영화, 게임과 같은 다양한 디지털 콘텐츠를 TV라는 매체를 통해 PC와 같은 TV와는 다른 디바이스에 존재하는 다양한 콘텐츠를 손쉽게 즐길 수 있는 콘텐츠 서비스의 형태라고 할 수 있다. 이러한 다양한 기기에 존재하는 콘텐츠를 손쉽게 이용할 수 있는 허브 장치로서 STB(Set-top Box)가 대두되고 있다. STB가 허브 장치로서의 기능을 하기 위해서는 서로 다른 기기들과의 연계시 발생하는 여러 문제점들(예 : 조작의 불편)을 해결하고 이를 통합 조정할 수 있는 어플리케이션이 필요하다. 본 논문에서는 STB와 멀티미디어 기기 중의 하나인 HTPC(Home Theater PC)를 예를 들어 두 기기간의 연동 환경에서 STB 리모컨을 통해 HTPC를 제어할 수 있는 어플리케이션에 대해 연구한다. 이를 위해 이종 단말기 간의 연동을 위해 RMI(Remote Method Invocation)의 클라이언트/서버 통신 메커니즘을 응용하였다. 이를 통해 HTPC 뿐만이 아닌 다양한 디바이스를 STB에 연결하여 활용할 수 있는 좋은 예가 될 수 있을 것이다.

• Journal of Advanced Navigation Technology
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• v.16 no.5
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• pp.864-870
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• 2012

Voice pattern recognition technology to solve the problems of the existing problems and common issues that you may have in language learning content analysis. This is the first problem of language-learning content, online learning posture. Game open another web page through the lesson, but the concentration of the students fell. Have not been able to determine the second issue according Speaking has made the learning process actually reads. Third got a problem with the mechanical process by a learning management system, as well by the teacher in the evaluation of students and students who are learning progress between the difference in the two. Finally, the biggest problem, while maintaining their existing content made to be able to solve the above problem. Speaking learning dedicated learning programs under this background, voice pattern recognition technology learning process for speech recognition and voice recognition capabilities for learning itself has been used in the recognition process the data of the learner's utterance as an audio file of the desired change to a transfer to a specific location of the server or SQL server may be easily inserted into any system or program, any and all applicable content that has already been created without damaging the entire component because the new features were available. Contributed to this paper, active participation in class more interactive teaching methods to change.

• Journal of Digital Contents Society
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• v.14 no.4
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• pp.513-519
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• 2013

In this paper, we provide interfaces according to user application environments and provide tools through web-site that users can create interface to apply a wide range of application environment. HTML5 is used in the creation processing, so users can create various interfaces by dragging mouse and apply it to multimedia, game applications as well as documents by using the ASCII code and key events that are provided in the Android OS. Database of interfaces is stored in HDFS (Hadoop Distributed File System) based on Hadoop for management and users can have their own designed interface or select interfaces through simple login any time. In order to provide interface quickly, HIVE based on Hadoop is used for search and the data is provided in XML file which smart mobile can process quickly.

• Journal of Korea Multimedia Society
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• v.7 no.3
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• pp.377-387
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• 2004

This paper describes a tree-based conversational interface supporting efficient presentation of turn relations on online conversation. Most of conventional conversational interfaces are difficult to make use of formal conversation such as group meeting, decision-making, etc. due to very simplicity of a con versational interface and restriction of data structure of conversational messages. And a tree-based conversational interface supports formal conversation, but they are difficult to present turn relations because of jumpy display by locations of replied turns and distance between replied turns, etc. So this paper suggests a tree-based conversational interface to present efficiently turn relations using XML-based messages with merits of a text-based interface. The suggested conversational interface was implemented by using XML-, DOM, and JDK. And this paper showed that the conversational interface could be applied to conversation system using client- server architecture. Applications for the conversational interface are as follows: collaboration, distance teaming, online game, etc.

• Journal of Digital Convergence
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• v.12 no.2
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• pp.277-283
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• 2014

Recently, various cloud service has been being provided on mobile devices as well as desktop pc and server computer. Also, Smartphone users are very rapidly increasing, and they are using it for enjoying various services(cloud service, game, banking service, mobile office, etc.). So, research to utilize resources on mobile device has been conducted. In this paper, We have suggested efficient method of cloud resource management by using information of available physical resources(CPU, memory, storage, etc.) between mobile devices, and information of physical resource in mobile device. Suggested technology is possible to guarantee real-time process and efficiently manage resources.