• 한국IT서비스학회지
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• 제9권2호
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• pp.151-161
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• 2010

Recently, as the era of ubiquitous has arrived, an infrastructure for the short-distance wireless communication has been extended socially, and thus a variety of services are being proposed. The Multimedia Contents Delivery System using the ZigBee, in particular, has an important stance in enlargement of a variety of services in the aspect of individual-oriented service support though Wireless Personal Area Network (WPAN). Nonetheless, the ZigBee, or the IEEE 802.15.4 Standard, has many restrictions on the Multimedia Contents Delivery System due to the low data transport rate. In order to improve the ZigBee which presents a limit on the transport rate at the IEEE 802.15.4 Standard, this thesis has designed the burst mode which is a method of transmitting a certain amount of data in block units at a high speed without any stoppage until the completion of the transmission. Also, to provide a Multimedia Contents Delivery Service with an application of the normal data transmission mode, it improved the transmission performance of the ZigBee. In addition, for the Multimedia Contents Delivery Service under the ubiquitous environment, it designed and implemented a broadcasting Multimedia Contents Delivery System based on the ZigBee to conduct a comparative analysis on the data transmission performance according to the transmission method.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1460-1465
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• 2016

In this paper, we propose an energy efficient and multimedia traffic friendly MAC protocol (EEMF-MAC) that controls sender's wakeup period based on the data packet's transmission urgency and the receiver's wakeup periods based on the received data packet traffic loads. The protocol is useful for applications such as object tracking, real time data gathering, in which priority-based packet transmission is required. The basic idea of EEMF-MAC is that it uses the priority concept with transmission urgency of sender's data packet to reduce the transmission delay of the urgent data and it also uses duty cycling technique in order to achieve energy efficiency. EEMF-MAC showed a better performance in energy efficiency and packet transmission delay compared to existing protocols, RI-MAC and EE-RI-MAC.

• 한국멀티미디어학회논문지
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• 제9권4호
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• pp.490-504
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• 2006

분산 환경에서 멀티미디어 라이브 스트리밍을 지원하는 멀티미디어 서비스를 구현하기 위해서는 다양한 플랫폼에 분산되어 있는 객체들을 제어하고, 멀티캐스트를 지원하지 않는 네트워크 환경에서 다수의 수신자에게 멀티미디어를 전송하는 것이 필요하다. 본 논문에서는 분산 객체 기술인 RMI와 멀티미디어 전송/처리에 사용하는 JMF를 확장하여 분산 환경에서 1:N 의 멀티미디어 라이브 스트리밍을 지원하는 DLS (Distributed Live Streaming) 패키지를 제안한다. 효율적인 분산 처리를 위해 전송과 제어를 분리하여 설계한 자바 기반의 DLS 패키지는 1:N의 전송을 지원하고 플랫폼 독립적인 멀티미디어 서비스의 개발에 적용이 가능하다.

• 한국멀티미디어학회논문지
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• 제6권6호
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• pp.1025-1033
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• 2003

최근 인터넷 이용자의 급증과 멀티미디어 컨텐츠의 증가로 인한 네트워크의 정체 현상을 해결하기 위한 방안으로 CDN 기술이 대두되고 있다. 본 논문에서는 멀티미디어 컨텐츠를 안정적이고 신속하게 전송할 수 있는 방안으로 CDN 인프라를 기반으로 하여 CDN 서버 그룹간의 멀티캐스트 전송과 CDN 서버와 사용자 사이에 다중 코딩과 다중 경로 전송을 제안하였다. 이러한 연구는 멀티캐스트 전송에 있어서의 비 신뢰성 문제를 해결하고 멀티미디어 컨텐츠의 전송 효율을 높여 웹 컨텐츠 분야의 새로운 비즈니스 모델 창출에 기여할 수 있을 것이다.

• 한국통신학회논문지
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• 제25권9A호
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• pp.1340-1347
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• 2000

The international mobile telecommunication-2000(IMT-2000) system can support not only the non-realtime multimedia traffic such as data such as data image but also the realtime multimedia traffic such as voice, video. In the paper we propose multicode allocation and handoff schemes for efficient transmission of realtime and non-realtime data in cdma2000. In those schemes the bandwidth of target cell is reserved based on moving direction of mobiles to support QoS of realtime multimedia data and the reserved bandwidths is used by the non-realtime mobiles of the target cell until the mobiles want to perform hadoff. Our framework is able to guarantee QoS continuity of realtime multimedia data and carries the maximum number of subscriber. System performance is evaluated and compared with conventional scheme considering transmission delay channel utilization and blocking probability by computer simulation.

• 제어로봇시스템학회논문지
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• 제11권4호
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• pp.385-391
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• 2005

As the Internet real-time multimedia applications increases, the bandwidth available to TCP connections is oppressed by the UDP traffic, result in the performance of overall system is extremely deteriorated. Therefore, developing a new transmission protocol is necessary. The TCP-friendly algorithm is an example satisfying this necessity. The TCP-Friendly Rate Control (TFRC) is an UDP-based protocol that controls the transmission rate that is based on the available round trip time (RTT) and the packet loss rate (PLR). In the data transmission processing, transmission rate is determined based on the conditions of the previous transmission period. If the one-step ahead predicted values of the control factors are available, the performance will be improved significantly. This paper proposes a prediction model of transmission rate control factors that will be used in the transmission rate control, which improves the performance of the networks. The model developed through this research is predicting one-step ahead variables of RTT and PLR. A multiplayer perceptron neural network is used as the prediction model and Levenberg-Marquardt algorithm is used for the training. The values of RTT and PLR were collected using TFRC protocol in the real system. The obtained prediction model is validated using new data set and the results show that the obtained model predicts the factors accurately.

• 한국멀티미디어학회지
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• 제1권1호
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• pp.19-32
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• 1997

There are many kinds of predominant modes to transfer Multimedia information on internet in the world. Various methods are applied to get real time multimedia data as possible as we need. At the moment it is very difficult to use acceptable technologies for performe those methods effectively on the Networks. This paper gives the alternative directions and trends for research and development of multimedia transmission on the internet. ATM is one of the best mode to transfer mass-multimedia data at the high speed on the Broad-Band ISDN until now. And xDSL (xDigital Subscriber Line) is an excellent typical method on the PSTN (Public Switched Telephone Network) using old type telephone line. But they are not yet applied into the phase of practical use together this time. So this paper analyzes what we need and how to develop the multimedia transmission modes which we can send on the internet without a problem or any difficulty for our various multimedia information all the time under low cost and high speed.

• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.33-41
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• 2020

Nowadays, distributed mobility management (DMM) approaches have been widely adopted to address the limitations of centralized architectural methods to support seamless data transmission schemes in wireless sensor networks. This paper deals with the end-to-end (E2E) integration of Network Mobility (NEMO) basic support protocol in distributed wireless sensor network systems in structural health and environmental monitoring of social overhead capital (SOC) public infrastructures such as bridges, national highways, tunnels, and railroads. The proposed scheme takes advantage of the features of both the NEMO basic support protocol and partially distributed network-based DMM framework in providing seamless data transmission and robust mobility support. The E2E seamless data transmission scheme allows mobile users to roam from fixed-point network access locations and mobile platforms (i.e., vehicles such as cars, buses, and trains) without disconnecting its current sessions (i.e., seamless handover).

• 한국정보통신학회논문지
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• 제5권6호
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• pp.1104-1109
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• 2001

본 논문은 비디오 스트림을 실시간에 전송하기 위하여 RTP(Real-Time Protocol)을 이용한 전송 기법에 관한 연구이다. 먼저, 비디오 스트림의 연속적인 전송을 보장하기 위해 네트워크의 종단간 지연 특성을 분석하여 네트워크 상황을 파악하는 방법과 불규칙한 대역폭을 극복하기 위한 버퍼링 기법과 RTCP(Real-Time Control Protocol)를 이용하여 데이터의 전송 상태를 분석하여 실시간으로 멀티미디어 데이터를 전송할 경우 QoS를 보장하고 연속성을 유지할 수 있는 알고리즘을 과 성능 분석 결과를 제시하였다.

• 한국통신학회논문지
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• 제33권4B호
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• pp.192-198
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• 2008

본 논문에서는, HCCA로 동작되는 IEEE 802.11e MAC의 Transmission Opportunity (TXOP) 구간을 동적으로 제어함으로서, 무선 Local Area Network (LAN) 환경에서 실시간 멀티미디어 트래픽의 전송 성능을 향상시키는 방식을 제안한다. 프레임의 전송 시기 및 시간을 결정하는 스케줄러의 기존 방식은 무선 단말의 전송률 변화에 상관없이 TXOP 구간을 고정하기 때문에 무선 통신 환경 변화를 동적으로 반영하지 못하는 문제점을 내포하고 있다. 이러한 문제점을 해결하기 위하여 제안방식에서는 무선 단말의 전송률이 낮아지더라도 TXOP 구간이 확대됨으로서, 사용자로부터 발생된 실시간 멀티미디어 트래픽의 전송이 최대한 유지될 수 있도록 한다. 제안방식의 성능 분석을 위해, IEEE 802.11e 참조모델과 함께 NCTUns 시뮬레이터를 이용한 모의실험을 수행하였으며, 그 결과 제안방식은 무선통신 거리 변화에 따른 전송률 변화에도 실시간 멀티미디어 트래픽의 전송이 효과적으로 이루어짐을 확인하였다.