Streaming Delay Research Articles

Media handling for multimedia conferencing in multihop cellular networks

This article addresses the media-handling aspects of multimedia conferencing in multihop cellular networks. Participation in multimedia conferences in MCNs may be confined to either the conventional cellular network or the MANET. Participation also can span both networks. However, neither the media-handling architectures currently in use in conventional cellular networks, nor the ones in use in MANETs are appropriate. When they are used, either the participants in the conventional cellular network, or the ones in the MANETs, might experience long and potentially unacceptable end-to-end stream delays. Furthermore, these architectures are the antipodes of each other. Reconciling them is not an easy task. We evaluate the architectures currently in use in cellular networks and MANETs, show that none is suitable, and propose a new architecture that bridges the two worlds. The new architecture uses the MANET media-handling architectures as a starting point. It is based on media mediators. A media mediator is composed of two functional entities: the media gateway controller mediator and the media gateway mediator. A proof-of-concept prototype was implemented, and extensive simulations were conducted to evaluate performance.

Push-Pull Two-Layer Super-Peer based P2P Live Media Streaming

Peer-to-peer (P2P) file sharing has become increasingly popular, accounting for as much as 70% of Internet traffic by some estimates. Recently, we have been witnessing the emergence of a new class of popular P2P applications, namely, P2P audio and video streaming. In this paper, we propose and investigate a full distributed, scalable, and cooperative protocol for live video streaming in an overlay peer-to-peer network. Our protocol, termed P2P Super-Peer based Unstructured Live Media Streaming (PALMS-SP), makes use of combination of push-pull scheduling methods to achieve high performance (in term of delay, stream continuity, cooperation, etc.). The main contribution of PALMS-SP is that it reduces the end-to-end streaming delay and in turn results better delivered quality. We have extensively evaluated the performance of PALMS-SP. Our experiments demonstrate that PALMS-SP with the existence of super-peers achieves better streaming quality in comparison with other existing streaming applications.

Prediction of minor stream delays at a limited priority freeway merge

This paper presents the development and application of a limited priority gap acceptance model to freeway merging. In the limited priority model, drivers in the major stream at a merge area may incur delay in restoring small headways to a larger, sustainable minimum headway between them and the vehicle in front. This allows minor stream drivers to accept smaller gaps. The headway distributions are assumed to be distributed according to Cowan’s M3 model, whose terms were calibrated for this system. Minor stream minimum follow-on time was calibrated, and a realistic range of the critical gap identified. An equation was developed for minimum average minor stream delay. A function was identified to model the relationship between minor stream average delay and degree of saturation. The shape parameter of this function was calibrated using simulated traffic flow data, under three different minor stream arrival pattern regimes. The model provides a useful means of comparing performance, through average minor stream delay, for varying minor and major stream flow rates and minor stream critical gap, under arrival patterns that differ due to traffic control upstream of the on-ramp. Minor stream delay is a particularly useful measure of effectiveness for uncongested freeway merging as it relates directly to the distance required to merge. Observations from the model developed provide physical evidence that minor stream drivers incur lesser delay, or have a better chance of merging quickly, when they arrive at constant intervals as is the case under constant departure ramp metering, than when they arrive in bunches downstream of a signalised intersection, or even a semi-bunched state downstream of an unsignalised intersection.

Microscopic modelling of freeway operations : Bunker, Jonathan, Ph.D. Queensland University of Technology (Australia), 1996. 456 pp. Supervisor: Rod Troutbeck

Microscopic modelling of freeway operations : Bunker, Jonathan, Ph.D. Queensland University of Technology (Australia), 1996. 456 pp. Supervisor: Rod Troutbeck

癌のリンパ節転移に及ぼすレ線前照射の影響に関する実験的研究

On nidation of cancer cells a pure physical study of their permeability. was performed Further the irradiated lymphnodes were studied histologically and morphologically from a pure physical standpoint especially on their lymph stream way. The results were as follows:1) After prophylactic radiations of 60 r, 600 r or 300 r×5, the little granuli (the spores of myxomycetes), the size of small cancer cells, were injected into the lymphnodes. Then their permeability was compared with that of the non-irradiated lymphondes. The spores generally decreased with the lapse of time in the latter while in the former the permeability was disturbed and the spores remained for comparatively long time.2) Instead of the spores, Brown-Pearce tumor cells were injected. The result was the same as in the case of the spores. They remained for longer period in the marginal sinus and in the intermediate sinus of the lymphnodes which had been irradiated with 600 r and 300γ×5.3) The lymph sinus as a way of lymphatic stream was dilated in case of irradiation by 600 r and 300 r×5 both in marginal and marrow sinus. Also a lymphatic stagnation was found.4) It seems that the delay and slowness of lymph stream which comes from the dilation of lymph sinus is the reason of the spores or the Brown-Pearce tumor cells remaining comparatively in number when 600 r and 300 r×5 X-rays are radiated to the lymphnodes.5) The reticular fibres which lay relatively densely at the border of the intermediated and marrow sinus are considered to hold the stream of the little granuli or tumor cells from the marginal sinus into the marrow sinus to some degree.6) The prophylactic radiation is considered to make the nidation of cancer cells easier.