• Journal of the Korea Computer Industry Society
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• v.3 no.8
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• pp.1027-1038
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• 2002

Multimedia data services have been widely developed with the recent progression of the Internet technology. Multimedia services, especially, must guarantee Quality of Service with restricted environment resources. The abrupt increase of transmission quanta, so called burst, and the number of client that access multimedia server, with limited network bandwidth will demage the quality of service and the utilization of network resource. Smoothing techniques can reduce the burst of a variable bit rate stream by transmitting data at a series of fixed rates. In this paper, we present a new smoothing algorithm using MPEG's characteristics in transmitting stored video data with VBR. The smoothing algorithm we present will be verified with assorted existing techniques in diverse environments.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.10
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• pp.2292-2300
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• 2015

Car rear-view camera system supplies services for safe driving and easy parking by showing the rear-view of the vehicle through a monitor when reversing the car. In this paper we researched implementation methods and technology of a Car Rear-view Camera System based on the Binary CDMA technology-new technology of wireless personal area network developed by Korea - that makes free installation without wired cables restriction and reduces installation costs. Through this research we manufactured a prototype system, and researched the implementation of camera input and monitor output modules, Binary CDMA wireless communication and application programs for wireless video transmitter and relay server.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.8
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• pp.1743-1749
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• 2011

The multimedia data for video-on-demand(VOD) service has large, continuous and real time characteristics. The frequent disk I/O operations takes much time and decrease the system performance in multimedia services. Therefore the efficient buffer management is needed in order to reduce the disk accesses to multimedia data. This paper addresses how to increase the buffer hit ratio and the number of users in a multimedia service like VOD by increasing the utility of buffer. This paper also simulated various resource management algorithms and strategies and evaluated, compared and analyzed their performances.

• Journal of Communications and Networks
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• v.14 no.3
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• pp.319-335
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• 2012

In this study, we design an applicable model enabling internet protocol television (IPTV) service providers to use a virtual network (VN) for IPTV service delivery. The model addresses the guaranteed service delivery, cost effectiveness, flexible control, and scalable network infrastructure limitations of backbone or IP overlay-based content networks. There are two major challenges involved in this research: i) The design of an efficient, cost effective, and reliable virtual network topology (VNT) for IPTV service delivery and the handling of a VN allocation failure by infrastructure providers (InPs) and ii) the proper approach to reduce the cost of VNT recontruction and reallocation caused by VNT allocation failure. Therefore, in this study, we design a more reliable virtual network topology for solving a single virtual node, virtual link, or video server failure. We develop a novel optimization objective and an efficient VN construction algorithm for building the proposed topology. In addition, we address the VN allocation failure problem by proposing VNT decomposition and reconstruction algorithms. Various simulations are conducted to verify the effectiveness of the proposed VNT, as well as that of the associated construction, decomposition, and reconstruction algorithms in terms of reliability and efficiency. The simulation results are compared with the findings of existing works, and an improvement in performance is observed.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.11a
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• pp.403-405
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• 2009

통방융합 환경에서 Killer 서비스로 각광을 받고 있는 VOD(Video On Demand)서비스에서 I/O 병목현상은 VOD 서버의 오 동작 및 성능 저하의 주요 원인이 되고 있다. 본 논문에서는 이런 I/O 병목 현상을 개선하여 입출력 효율이 좋은 고성능 VOD 솔루션을 제안한다. 제안된 솔루션은 대용량 더블 버퍼를 구성하여 하나의 버퍼로 클라이언트에 데이터를 전송하고 있는 사이에, 나머지 다른 버퍼에서 스토리지에서 전송되는 데이터를 버퍼에 저장 하여, 디스크 접근 시 한번에 보다 많은 데이터를 읽음으로써 연속적인 정보를 가져올때 빈번하게 하드디스크의 접근을 줄임으로서 끊김없는 전송을 가능하게 한다. 또한 다수의 사용자가 동시 접근 시 데이터 충돌을 방지하고, 스토리지에 순차적으로 연속 접근하도록 접근 발생 시간에 따라 우선 순위 인덱스를 할당하고 회수하도록 스토리지 접근 스케쥴러를 고안 하였다. 제안된 솔루션의 유효성을 검증하기 위해 SD급 콘텐츠에 대해 솔루션의 Throughoutput 처리량을 벤치마킹 테스트로 검증을 하였다. 테스트 결과 MPEG-2 SD급 영상에대해 Raid 5에서 최대 1000 스트리밍을 전송 할 수 있음을 확인 하였다.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2424-2430
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• 2012

The current Navigation System for the Visually Impaired Person has a short and limited communication distance and can't receive enough information from Visually Impaired Person to assist directly. In addition, because the path is dangerous and incomplete for the Visually Impaired Person, moving with White Stick is still inconvenient and dangerous. To solve this problem we implement communication that can send and receive video, voice, location information between the Visually Impaired Person's Smart Portable Navigation System Development and assistant's PC.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.79-84
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• 1998

This paper describes implementation of the core DSM-CC UU interface. It briefly describes the reference model for the DSM-CC and related standards that should be reviewed for the implementation. The Common Object Request Broker Architechture, Revision 2.0 (CORBA 2.0) is sued as a remote procedure call (RPC) scheme for the UU Interface. Entire system was implemented with C++ on Windows NT platforms. The implementation procedure has been decomposed ito two tasks. The first task is to implement the Naming Service for service navigation. The Naming Service is one of the CORBA Services that extend the core CORBA specification. A client GUI is implemented for easy navigation among various services. The second task is to construct multimedia server and client for a Video-on-Demand (VoD) system. MPEG-2 Transport Stream is transported via ATM AAL5 using the Windows Socket 2.2 ATM extension API. A GUI enables the user to navigate the service domain and select a program. After the selection the user can control the MPEG-2 stream with VCR-like buttons.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2005.11a
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• pp.255-259
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• 2005

본 논문은 시청자가 TV를 시청하다가 마음에 드는 화면이 있으면, 이를 캡춰해서 친구들에게 메시지로 보내는 서비스를 구현하는 방법을 기술한다. 이를 위해서는 셋톱박스에서 실행되는 Xlet 애플리케이션에서 비디오 스트림의 특정화면을 캡춰할 수 있어야 하는데, 현재 미들웨어는 이런 기능을 제공하고 있지 않다. 따라서, 본 논문에서는 Xlet application 에서 시청자가 지정한 화면의 시점값을 방송국 서버로 전송하고, 서버에서 해당 화면을 캡춰하여 이를 시청자가 원하는 수신자에게 보내주는 방법을 사용한다. 미들웨어 API 표준에서 현재의 NPT (Normal Play Time) 을 알려주는 API 를 제공하므로, 애플리케이션에서 시청자가 원하는 시점의 NPT 를 구해 이를 방송국 서버로 보내고, 서버에서는 이 NPT 에 해당되는 동영상의 미디어 타임을 구해, 그 시간에 해당되는 프레임을 계산하여 화면을 캡춰한다. 본 기술을 활용하면 서버에서 캡춰된 화면을 Mobile, Web 등의 매체에도 전송할 수 있으므로 유무선통합, 방통융합형 서비스로 확장해 나갈 수 있다.

• Journal of Korea Society of Digital Industry and Information Management
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• v.7 no.3
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• pp.85-95
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• 2011

Smart phones, greatly expanding in the recent mobile market, are equipped with various features compared to existing feature phones and provide the conveniences to in several ways. The camera, one of the features of a smartphone, creates the digital contents, such photos and videos, and plays a role for the media which transmits information, such as video calls and bar code reader. QR-Code recognition is also one of the camera features. It contains a variety of information in two-dimensional bar code type in matrix format, and makes it possible to obtain the information by using smart phones. This paper analyzes the method of QR-Code recognition, password method-the existing user-authentication technique, smart card, biometrics and voice recognition and so on and thenn designs a new user-authentication technique. The proposed user-authentication technique is the technique in which QR-Code, which can be simply granted is read by smart phones and transmitted to a server, for authentication. It has the advantages in view that it will simply the process of authentication and conteract the disadvantages, such as brute force attack, man-inthe-middle attack, and keyboard hacking, which may occur in other authentication techniques.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1695-1703
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• 2014

Manipulating a car navigation system while driving can lead to car accident due to loss of concentration. This will be more serious for elders or beginner drivers. Recently, a new Road Traffic Law in Korea prohibits drivers from watching or operating any video displaying devices. So the car navigation system came hard to use. In order to solve the issue we design and implement a novel system where a remote person can control the car navigation system on behalf of the driver. In the proposed system, we suggest to utilize the driver's smartphone for allowing sharing the Internet connection of the phone with the navigation system. The required smartphone application and the server will also be designed and implemented.