• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.95-98
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• 2003

To provide high-quality media streaming service over the best-effort Internet, an efficient streaming system with a network-adaptive transport is essential. By adopting FEC-based adaptive transport and by matching it to the priority of media packets, in this paper, an enhanced MPEG-4 streaming system is implemented. The implemented adaptive transport can complement the existing MPEG-4 streaming server with components such as elementary stream provider, sync layer and DMIF layer. Sync layer packets of each MPEG-4 elementary stream are prioritized and then selectively dropped at the sender to match the currently available bandwidth. Also, with the proposed adaptive transport module, the level of FEC protection is dynamically adjusted based on the underlying network condition. With preliminary verification over the emulated network testbed, it is shown that the proposed implementation can mitigate the impact of network fluctuation and thus improve the quality of streaming.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.3B
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• pp.85-94
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• 2005

In this paper, we propose a reliable high-speed UDP-based media transport with an adaptive error control. The proposed adaptive transport scheme controls the amount of redundancy by monitoring the network in order to adapt to network fluctuations efficiently. The feedback of receiver enables the sender to be aware of current reception status (i.e., rate and type of packet loss) and to estimate the expected network status. Based on this, the proposed transport attempts to enable reliable transport by adaptively controlling the amount of both whole sending rate and the ratio for adaptive FEC code. Experiment with high-speed network has been conducted to verify the performance of the proposed system that demonstrates the enhanced reliability of the proposed transport at the speed of up to several hundred Mbps.

• International Journal of Railway
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• v.5 no.4
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• pp.135-138
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• 2012

The article suggests criteria of dividing transport systems into systems of limited and open access. Possibilities of implementing principles of the open access in conjunction with the adaptive control at the railway transport have been analyzed. The author makes a grounded conclusion that the development of transport systems based on the open access and adaptive control can play a positive role in overcoming the global instability of the economy and form prerequisites of its stable grows.

• 한국HCI학회:학술대회논문집
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• 2008.02c
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• pp.12-18
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• 2008

This paper introduces the existing network-adaptive transport techniques for haptic-enhanced system. First we classify haptic-based network systems according to the communication architecture and data type. Then the existing studies concerning network QoS requirements for haptic-based network system are depicted. Finally, the survey of network-adaptive transport schemes is introduced devided into three key issues: delay and jitter compensation, error control, and transmission control.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.8A
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• pp.859-867
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• 2004

To provide high-quality media streaming service over the best-effort Internet, a streaming methodology is required to response to the dynamic fluctuation of underlying networks. In this paper, we implement the MPEG-4 streaming system with adaptive transport based on priorities of media packets. The implemented system is composed of the common MPEG-4 streaming components such as elementary stream provider, sync and DMIF layer, and adaptive transport module including data prioritization and FEC control. More specifically, the prioritized sync layer packets (based on object level) are delivered to the transport module and then are encoded by an adaptive FEC encoder to help reliable transport. The FEC combination is dynamically adjusted by the feedback information from the receiver. In addition, low priority packets are selectively dropped to meet the limitation of available bandwidth. The experimental results over the emulation-based testbed show that the Proposed system can mitigate the impact of network fluctuation and thus improve the quality of streaming.

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.367-370
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• 2008

• 한국ITS학회:학술대회논문집
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• 2008.11a
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• pp.360-363
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• 2008

• 한국ITS학회:학술대회논문집
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• 2002.11a
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• pp.88-91
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• 2002

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.4B
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• pp.208-216
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• 2007

Wireless Sensor Networks (WSNs) are characterized by low capacity on each nodes and links. Wireless links have high bit error rate (BER) parameter that changes frequently due to the changes on network topology, interference, etc. To guarantee reliability in an error-prone environment, a retransmission mechanism can be used. In this mechanism, the number of retransmissions is used as a parameter that controls reliability requirement level. In this paper, we propose an Error Adaptive Transport Protocol (EATP) for WSNs that updates the number of retransmissions regularly to guarantee reliability during bit error rate changes as well as to utilize energy effectively. The said algorithm uses local information, thus, it does not create overhead problem.

• Journal of Broadcast Engineering
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• v.10 no.4 s.29
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• pp.548-556
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• 2005

In wireless network environments, wireless channels are characterized by time-varying fading and interference conditions, which may lead to burst packet corruptions and delay variation. This can cause severe quality degradation of streaming media. To guarantee successful transmission of media over the hostile wireless networks, where channel conditions are highly fluctuating, a flexible and network-adaptive transport method is required. Thus, we propose a network-adaptive transport error control consisting of packet-level interleaved FEC and delay-constrained ARQ, which acts as an application-level transport method of streaming media to alleviate burst packet losses while adapting to the changing channel condition in wireless networks. The performances of the proposed network-adaptive transport error control, general error control schemes, and hybrid schemes are evaluated by a developed simulator at the transport-level and video quality of streaming media. Simulation results show that the proposed mechanism provides the best overall performance among compared other schemes in terms of the transport-level performance of error control and the performance of video quality for streaming media.