• Journal of Broadcast Engineering
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• v.20 no.1
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• pp.110-121
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• 2015

The digital app-book is an advanced form of the electronic book (e-book), which attracts a lot of interests by the help of video, sound, sensors and a variety of interactions. As mobile devices have evolved, the demand of digital app-books is also rising substantially. However, the distribution of digital app-book contents is hard to meet the demand because the digital app-book requires a lot of programming cost for the interaction. To resolve this problem, Was verified and implementation as a library function of the interaction between device and user. The proposed library consists of three parts (user action recognition, device action, and content action) and provides various user-device interaction functions by combining methods of each part, which can support source code reusability, easy understanding and availability, and wide expandibility. The library was used in the development of natural science education app-book contents. As a result, it could reduce a lot of code lines and facilitate more rapid app-book development.

• Journal of Korea Multimedia Society
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• v.14 no.6
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• pp.785-793
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• 2011

Since then, with the advance of computing environment, various Internet services are emerging and the importance of user authentication technology is increasing for verifying users authorized to use such services. Along with the advance of authentication technology, research is being made actively on one time password, which is used once in a session and then discarded. In existing one time passwords, however, the values of one time passwords in a created table are stored in serial order, and therefore, if the seed value and the number of one time passwords used are disclosed, one may infer the value of the one time password to be used next. What is more, one time passwords of the S/Key type have the problem that the number of uses is fixed. In this paper, We analysis the existing one time password. Also, We propose one time password methods using elliptic curve cryptography scheme and using enhanced randomness with time value.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2013.06a
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• pp.97-100
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• 2013

최근 4세대(4G) 통신망으로의 전환의 가속화와 스마트 모바일 기기의 확산으로 인하여 무선 통신망에서 데이터 트래픽이 급증하고 있다. 이러한 급증하는 데이터 트래픽을 분산시키기 위하여 2개의 주파수 밴드를 사용하는 멀티 캐리어 기술이 선보이고 있다. 방송 디스크는 서버가 데이터베이스에 저장된 모든 데이터를 연속적으로 다수의 모바일 클라이언트에게 방송하고, 클라이언트는 방송 채널을 감시하여 원하는 데이터가 방송될 경우 방송 채널로부터 데이터를 수신하는 통신 구조이다. 이런 관점에서 방송 채널은 클라이언트가 데이터를 액세스할 수 있는 디스크의 역할을 담당한다. 본 논문에서는 무선 통신망이 멀티 캐리어를 지원할 경우, 클라이언트에서 실행되는 읽기 전용 트랜잭션의 정확성을 보장하기 위한 동시성 제어 기법(Dual-Channel based Concurrency Control: DCC)을 제안한다. 기존에 동시성 제어 기법들은 단일 방송채널에서 트랜잭션의 철회률을 줄이기 위하여 추가적인 제어 정보들을 방송하거나 방송 데이터의 타임스탬프 필드를 이용하고 있다. 클라이언트에서 실행되는 트랜잭션은 단일 방송 사이클이 아니라 여러 방송 사이클에 걸쳐서 실행된다. 이러한 방송 디스크 환경의 특징은 클라이언트 트랜잭션이 디스크에서 방송 인덱스를 판독하여 방송 프로그램 상에서 트랜잭션에 필요한 데이터가 방송 될 때까지 기다리게 된다. 이와는 달리 DCC는 주력 망과 보조 망에서 방송되는 방송 프로그램의 순서를 서로 다르게 하여 데이터 판독에 필요한 대기 시간을 줄일 수 있다. 보조망의 방송 프로그램의 순서는 주력망의 방송 프로그램 순서의 역순서로 방송함으로써 보조 망 또는 주력 망에서 실행되고 있는 트랜잭션이 다른 방송 채널의 방송 인덱스를 판독하지 않아도 방송 프로그램 순서를 예측할 수가 있다. 그 결과, DCC는 방송 디스크의 데이터 판독에 요구되는 대기시간을 줄여 읽기 전용 트랜잭션의 철회률을 줄일 수 있다는 장점을 갖는다.

• Journal of Korea Multimedia Society
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• v.11 no.5
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• pp.703-709
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• 2008

The methodology of the compiler construction improved by well-defined parsing techniques and developments of automatic generation tools. Through them, a variety of compilers for the special applications can be developed effectively: particularly, the compiler for embedded/mobile devices. Also, as contents industry is proliferating recently, the necessity of developing a compiler which is suitable for contents system is highly increasing. These various demands can be resolved by modular techniques and automatic construction of compilers. But, optimization of compiler itself as development tools uses heuristic methods and it needs higher cost. In this paper, we suggest the parsing method which can decrease unnecessary reduce actions by analyzing the characteristics of LR parser. The suggested parsing technique uses lookahead/ states, reachable reduction goals information in parsing process and enhances the parsing efficiency by changing continuous reduce actions to one. Actually, we applied it to the front-end of ANSI C compiler and proved the parsing performance in terms of the number of reduce actions.

• Journal of Korea Multimedia Society
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• v.8 no.9
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• pp.1282-1291
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• 2005

This paper presents the EVM(Embedded Virtual Machine) which enables the execution of dynamic applications loaded in the embedded systems such as Mobile Devices(mobile phone, PDA), Set-Top Box, and Digital TV using downloading techniques. To accomplish this goal, we defined a SIL-(Standard Intermediate Language) code, and implemented a Bytecode-to-SIL translator which enables the execution of programs written in java language in the EVM platform without JVM, and a MSIL--to-SIL- translator which enables for programs written in .NET language to be executed in the EVM platform without .NET platform. Also, we developed a EFF(Executable File Format) builder as an assembler which translates SIL codes into an executable file, *.evm, and implemented the EVM which reads the *.evm file and executes it. The virtual machine for embedded systems developed in this paper is the software technologies that enable the execution of applications or contents without changes to when the platforms change. In fact, the virtual machine suggested here is not only usable as a standard model for existing virtual machines but also aid in more efficient execution of applications loaded in the embedded systems such as Mobile Devices, Digital TV, and Set-Top Box.

• Journal of Korea Multimedia Society
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• v.16 no.9
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• pp.1077-1088
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• 2013

As broadcasting is the process that a node sends a packet to all nodes in the network. it is basic process used for discovering of a routes to a node and disseminating of control information message in Mobile Ad hoc NETwork (MANET). In this paper, we propose dynamically adjusted probabilistic mechanism based on distance ratio and node density for broadcasting in MANETs. The distance ratio can be calculated as the ratio of the radio strength length to the distance from sender of a node, and node density can be get from 1-hop nodes of neighbours. A mobile node receiving broadcast packets determines the probability of rebroadcasting considering distance ratio and node density of itself. Rebroadcast probability will be set as low value to a node which is located in nearby area of sender and has high 1-hop node density, So it reduces packets transmission caused by the early die-out of rebroadcast packets. Compared with the simple flooding and fixed probabilistic flooding by simulation, our approach shows better performances results. Proposed algorithm can reduce the rebroadcast packet delivery more than 30% without scanting reachability, where as it shows up to 96% reachability compared with flooding.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.05a
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• pp.794-796
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• 2016

Recently terrestrial mobile multimedia broadcasting(T-DMB) service is being provided throughout the country are expanding and demand is increasing day by day. T-DMB has the advantage of being cheaper in cost than installing another mobile multimedia broadcasting. However, there are a variety data of additional and provide it difficult for localized emergency alert broadcasting services. In this paper, a method to solve this problem feature was designed to restrict incoming unidirectional / bidirectional authentication via T-DMB system. In the mobile device is received by the T-DMB broadcasting service authentication mechanism for re-transmission to the mobile device, and T-DMB receiving other registered users can view it impossible to receive the broadcast. Through the proposed system it is considered to be able to solve the problems of the existing T-DMB technology.

• Journal of Broadcast Engineering
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• v.23 no.2
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• pp.253-260
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• 2018

Personalized media broadcasting services can produce their own broadcasting contents with a variety of creative themes if they have just a transmission platform and devices that can obtain videos and voices of producers without the existing expensive equipment. In this paper, we develop and implement a new broadcasting system by applying this service framework to events such as seminars or academic conferences. The devices can be installed at each conference rooms and the integrated system transmitted to users. They can watch via their multi-resolution screen, such as smart-phones, laptops, and tablet PCs. It has the advantage of being able to receive real-time streaming and VOD services as well as additional information related to the conference. It is expected to provide convenience by allowing attendees to access the information via their devices, thereby creating an impact on participation and the underlying technology for the future research.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.132-144
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• 2004

With the rapid development of internet technology, the number of internet users and the amount of multimedia information on the internet is ever increasing. Recently, the web sites, such as e-business sites and shopping mall sites, deal with lots of image information. As a result, it is required to support content- based image retrieval efficiently on such image data. This paper proposes an intelligent image retrieval system, which adopts XML, technology. To support object-based col)tent retrieval on product catalog images containing multiple objects, we describe a multi -level metadata structure which represents the local features, global features, and semantics of image data. To enable semantic-based and content-based retrieval on such image data, we design a XML-Schema for the proposed metadata and show how to represent such metadata using XML- documents. We also describe how to automatically transform the retrieval results into the forms suitable for the various user environments, such as web browser or mobile browser, using XSLT The proposed scheme can be easily implemented on any commercial platforms supporting XML technology. It can be utilized to enable efficient image metadata sharing between systems, and it will contribute in improving the retrieval correctness and the user's satisfaction on content-based e-catalog image retrieval.

• Proceedings of the Korean Information Science Society Conference
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• 2006.06a
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• pp.379-381
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• 2006

모바일 표준 플랫폼 WIPI(Wireless Internet Platform for interoperability)는 모바일 단말기에 탑재되어 응용프로그램을 실행할 수 있는 실행환경을 제공하는 국내 모바일 표준 플랫폼이다. 2002년부터 개발이 시작되어 현재 WIPI 2.0 규격을 탑재한 모바일 단말기가 출시된 상황이다. WIPI 2.0 규격은 PC연결 등의 표준 입출력, 폰카메라, 위치알림 기능, 보안통신 등의 서비스까지 규격화하고 있으며, 차기 버전에서는 휴대폰은 물론 휴대인터넷이나 위성 디지털멀티미디어방송(DMB) 단말기 플랫폼으로의 확장도 모색되는 등 발전가능성이 크다. 그러나 WIPI가 고려되지 않고 설계된 현재의 운영체제상에서 구현된 표준 플랫폼은 설계상 제한이 있으며, 미들웨어의 성격이 강하기 때문에 특정하드웨어와 운영체제에서의 WIPI 지원여부에 따라 응용 분야에 제약이 가해진다. 본 논문에서는 모바일 디바이스를 위한 연구개발을 목적으로 개발된 오픈소스기반 운영체제인 OpenOS의 커널수준에서 WIPI 표준 플랫폼의 HAL(Handset Adaptation Layer)과 WIPI-C 필수 API를 구현하여 성능의 개선과 표준 플랫폼을 위한 운영체제로의 발전 및 활용 가능성을 제시한다.