scholarly journals Single-Channel Data Broadcasting under Small Waiting Latency

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Hsiang-Fu Yu

Due to the advancement of network technology, video-on-demand (VoD) services are growing in popularity. However, individual stream allocation for client requests easily causes a VoD system overload; when its network and disk bandwidth cannot match client growth. This study thus presents a fundamentally different approach by focusing solely on a class of applications identified as latency tolerant applications. Because video broadcasting does not provide interactive (i.e., VCR) functions, a client is able to tolerate playback latency from a video server. One efficient broadcasting method is periodic broadcasting, which divides a video into smaller segments and broadcasts these segments periodically on multiple channels. However, numerous practical systems, such as digital video broadcasting-handheld (DVB-H), do not allow clients to download video data from multiple channels because clients usually only have one tuner. To resolve this problem in multiple-channel broadcasting, this study proposes a novel single-channel broadcasting scheme, which leverages segment-broadcasting capability further for more efficient video delivery. The comparison results show that, with the same settings of broadcasting bandwidth, the proposed scheme outperforms the alternative broadcasting scheme, the hopping insertion scheme, SingBroad, PAS, and the reverse-order scheduling scheme for the maximal waiting time.

Author(s):  
L Jowsey ◽  
M Passmore

Underbody diffusers are used widely in race car applications because they can significantly improve the cornering capacity of the vehicle through the generation of a downforce. They are also likely to have a wider role in reducing the drag in road vehicles as it becomes increasingly important to reduce emissions of carbon dioxide. This paper reports on a wind tunnel investigation, using a simplified bluff body model, into the effect of splitting a simple plane diffuser into multiple channels. Tests are reported for a range of diffuser geometries suitable for road and race car applications. The results for the lift, the drag, and the incremental changes to the lift-to-drag ratio are reported and discussed in terms of the underbody pressures. While broadly similar trends to the single-channel plane diffuser are seen in the multiple-channel diffuser configurations, it was found that the effect of increasing the number of channels depended on the flow regimes present in the plane diffuser. At angles just above the plane diffuser optimum, where the flow is partially separated, the multiple-channel configurations give large improvements in the downforce with minimal increase in the drag, significantly extending the performance envelope. The pressure maps indicate that the gains occur through improved diffuser pumping and pressure recovery in both the inner and the outer channels.


Author(s):  
Konstantinos Kardaras ◽  
George I. Lambrou ◽  
Dimitrios Koutsouris

Background: In the new era of wireless communications new challenges emerge including the provision of various services over the digital television network. In particular, such services become more important when referring to the tele-medical applications through terrestrial Digital Video Broadcasting (DVB). Objective: One of the most significant aspects of video broadcasting is the quality and information content of data. Towards that end several algorithms have been proposed for image processing in order to achieve the most convenient data compression. Methods: Given that medical video and data are highly demanding in terms of resources it is imperative to find methods and algorithms that will facilitate medical data transmission with ordinary infrastructure such as DVB. Results: In the present work we have utilized a quantization algorithm for data compression and we have attempted to transform video signal in such a way that would transmit information and data with a minimum loss in quality and succeed a near maximum End-user approval. Conclusions: Such approaches are proven to be of great significance in emergency handling situations, which also include health care and emergency care applications.


2016 ◽  
Vol 755 ◽  
pp. 452-455 ◽  
Author(s):  
Alfred Švarc ◽  
Mirza Hadžimehmedović ◽  
Hedim Osmanović ◽  
Jugoslav Stahov ◽  
Lothar Tiator ◽  
...  

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