• 한국IT서비스학회:학술대회논문집
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• 2003.05a
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• pp.607-614
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• 2003

멀티미디어 스트림 전송에 있어서 대량접속자를 수용하기 위해서는 서버에 많은 리소스와 대역폭이 집중되어야만 하는데, 소수의 클라이언트 접속만을 수용할 수 있고 적은 리소스와 대역폭을 갖는 서버의 경우, 이미 접속한 클라이언트가 서버 기능을 해서 중계할 수 있다면, 추가적인 접속은 중계가 가능한 다른 클라이언트로 접속하게 할 수 있다. 이렇게 피라미드 형태로 접속이 분산하기 위해서 P2P 접속을 이용한다면, 적은 리소스와 대역폭을 가지고도 대량접속자를 수용할 수 있는 대안이 될 수 있다. 실제로 이러한 구조로 어떤 어플리케이션이 가능한지, 또 얼만큼의 성능개선효과가 있는지 고찰해보고자 한다.

• Journal of Broadcast Engineering
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• v.6 no.3
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• pp.234-245
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• 2001

According to market needs of better quality of service (QoS) for realtime multimedia services over Internet, they haute been standardizing RSVP, Intserv, and DiffiServ. This paper combines the benefits of RSVP/IntServ with scalable video encoding. We Propose that more important bit stream is given more priority such that limited network resources are reserved for the stream Various prioritizing approaches are proposed and compared to normal approach by using Network Simulator. The calculated QoS parameters such as Packet loss rate are used to calculate degree of degradation in video quality.

• 한국IT서비스학회:학술대회논문집
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• 2003.11a
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• pp.446-453
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• 2003

서버에 집중화될 트래픽과 부하를 사용자 네트워크 전체로 분산시킬 수 있는 방식을 멀티미디어 스트리밍에 적용하게 되면 이를 채택하지 않았을 경우와 대비하여 그 성능에 큰 편차를 보일 수 있다. 이를 채택한 경우와 그렇게 하지 않았을 경우의 성능대비를 어떻게 어떤 기준치를 가지고 할 것인가가 본 연구의 목적이라 할 수 있다. 최초의 소스를 제공하고 있는 스트리밍 서버로부터 말단에 있는 클라이언트 까지 여러 단계의 연결을 주어진 특정한 환경하에서 (1) 피라미드 계층처럼 형성하여 제시된 "실험군(P2P 방식)"과 (2) 순차적인 방식으로 연결한 그간의 방식 "비교군(유니캐스트 방식)" 간의 성능대비(Performance Evaluation)를 하기 위해서 필요한 척도(Criteria)와 준거틀(Framework)을 제시하는 것이 본 연구의 주된 내용이라 할 수 있다.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.510-516
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• 2008

In ubiquitous environment, there are no limits to utilize networks whenever and wherever you are. That pervasive networks are combined with the information devices and then create various services such as car navigation of LBS(location based service) and DMB(Digital Multimedia Broadcasting). As these kinds of services are getting more various, the complexity is also getting higher and ultimately the convergence will make people feel frustrated. One of the solutions is Context-Awareness[1] technology. User interface with context-awareness filters unnecessary information and prevents users from being blocked due to the massive information. In this paper, we describe the seamless service system based on location-awareness, which is a type of context-awareness. We developed the system based on UPnP AV Framework. This system provides the automatic terminal device selection for the nomadic user. The system establishes new connections for the ongoing streaming playback session with the new AV devices without substantial loss of playback so that the user can enjoy the seamless service. The AV device selection based on the user's location needs no user's intervention or notification so it achieves the improvement of usability and complexity.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.10a
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• pp.53-56
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• 2001

It has been increasing that the use of Mobile Internet these days. And the demand of user is changing from the text based services to multimedia based data services like pictures, sounds and streaming videos in Mobile Internet. In this paper, It is proposed a remote monitoring system that .an transfer the video data through WAP(Wireless Application protocol) based Mobile Internet used generally in anywhere. And this system is a low-cost efficient system compared with a existing high-cost Internet Camera system, using video module connected to Internet directly and PC-based server. In this paper, It is explained a design and implementation of such WAP-based remote monitoring system.

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.575-581
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• 2010

With widespread use of the Internet and improvements in streaming media and compression technology, digital music, video, and image can be distributed instantaneously across the Internet to end-users. However, most conventional Digital Right Management are often not secure and not fast enough to process the vast amount of data generated by the multimedia applications to meet the real-time constraints. The SVC offers temporal, spatial, and SNR scalability to varying network bandwidth and different application needs. Meanwhile, for many multimedia services, security is an important component to restrict unauthorized content access and distribution. This suggests the need for new cryptography system implementations that can operate at SVC. In this paper, we propose a new scrambling encryption for reserving the characteristic of scalability in MPEG4-SVC. In the base layer, the proposed algorithm is applied and performed the selective scambling. And it encrypts various MVS and intra-mode scrambling in the enhancement layer. In the decryption, it decrypts each encrypted layers by using another encrypted keys. Throughout the experimental results, the proposed algorithms have low complexity in encryption and the robustness of communication errors.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.27 no.1C
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• pp.21-35
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• 2002

Nowadays, in accordance with increasing expectations of multimedia stream service on the internet, a lot of distributed applications are being required and developed. But the models of the existing systems have the problems that cannot support the extensibility and the reusability, when the QoS relating functions are being developed as an integrated modules which are suited on the centralized controlled specific-purpose application services. To cope with these problems, it is suggested in this paper to a distributed QoS management system on CORBA, an object-oriented middleware compliance. This systems we suggested can provides not only for efficient control of resources, various service QoS, and QoS control functions as the existing functions, but also QoS control real-time negotiation and dynamic adaptation in addition. This system consists of QoS Control Management Module(QoS CMM) in client side and QoS Management Module(QoS MM) in server side, respectively. These distributed modules are interfacing with each other via CORBA on different systems for distributed QoS management while serving distributed streaming applications. In phase of design of our system, we use UML(Unified Modeling Language) for designing each component in modules, their method calls and various detailed functions for controlling QoS of stream services. For implementation of our system, we used OrbixWeb 3.1c following CORBA specification on Solaris 2.5/2.7, Java language, Java Media Framework API 2.0 beta2, Mini-SQL 1.0.16 and the multimedia equipments, such as SunVideoPlus/Sun Video capture board and Sun Camera. Finally, we showed a numerical data controlled by real-time negotiation and adaptation procedures based on QoS map information to GUIs on client and server dynamically, while our distributed QoS management system is executing a given streaming service.

• Journal of Advanced Navigation Technology
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• v.18 no.2
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• pp.121-127
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• 2014

The functionality of BNWAS and its operations are investigated through its international standard. But the BNWAS is being used currently in the ship had difficulty in monitoring. Several kinds of data are generated from many equipments in BNWAS, such as NMEA-0183 data or NMEA-2000. In this paper, we have proposed a method of the multimedia data transmission using a communication protocol based on slower NMEA-0183, which is mainly used in BNWAS. Data compression techniques are needed for smooth streaming services of the multimedia data in the low data rate over the NMEA-0183 interface. Although these data are mainly used for the instruments of ship, their efficient transmission may be needed if they are managed to control the BNWAS equipment with sensors.

• Journal of Broadcast Engineering
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• v.12 no.6
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• pp.542-554
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• 2007

Seamless streaming of multimedia content via heterogeneous networks to viewers using a variety of devices has been a desire for many multimedia services, for which the multimedia contents should be adapted to usage environments such as network characteristics, terminal capabilities, and user preferences. Scalability in video coding is one of attractive features to meet dynamically changing requirements of heterogeneous networks. Currently a new scalable video coding (SVC) is standardizing in the Joint Video Team (JVT) of the ISO/IEC Moving Picture Experts Group (MPEG) and the ITU-T Video Coding Experts Group (VCEG), which will be released as Extension 3 of H.264/MPEG-4 AVC. In this paper, we introduce new technologies of SVC and evaluate performance of it especially regarding on overhead bit-rate and coding efficiency to support spatial, temporal, and quality scalability.