Advances in Wireless Video Delivery Etoh, M.; Yoshimura, T.
Proceedings of the IEEE,
2005-Jan., 2005-01-00, 20050101, Letnik:
93, Številka:
1
Journal Article
Recenzirano
This paper reviews practical video delivery technologies, examining existing mobile networks, commercialized or standardized transport, and coding technologies. Compression efficiency, power ...dissipation, and error control are intrinsic issues in wireless video delivery. Among these issues, error control technologies are evaluated at four layers: 1) layer-1/2 transport; 2) end-to-end transport layer such as TCP/IP or RTP/UDP/IP; 3) error-resilience tool and network adaptation layer) and 4) source coder layer. Layer-1/2 transport tends to provide two distinct conditions: one quasi-error-free, in which upper layer error control technologies show a limited improvement, and one with a burst of errors during the fading period, in which the adaptability of error control is essential. Emerging mobile network quality of service will have a large variation of bandwidth and delay. Thus, adaptive rate control and error recovery are identified as more crucial issues for future research.
Most studies in the literature for video quality assessment have been focused on the evaluation of quantized video sequences at fixed and high spatial and temporal resolutions. Only limited work has ...been reported for assessing video quality under different spatial and temporal resolutions. In this paper, we consider a wider scope of video quality assessment in the sense of considering multiple dimensions. In particular, we address the problem of evaluating perceptual visual quality of low bit-rate videos under different settings and requirements. Extensive subjective view tests for assessing the perceptual quality of low bit-rate videos have been conducted, which cover 150 test scenarios and include five distinctive dimensions: encoder type, video content, bit rate, frame size, and frame rate. Based on the obtained subjective testing results, we perform thorough statistical analysis to study the influence of different dimensions on the perceptual quality and some interesting observations are pointed out. We believe such a study brings new knowledge into the topic of cross-dimensional video quality assessment and it has immediate applications in perceptual video adaptation for scalable video over mobile networks.
This article surveys wireless video applications that have been commercialized recently or are expected to go to market in 3G (and beyond) mobile networks, mainly covering error control technologies ...in view of "wireless video." We introduce several related 3GPP standards including circuit-switched multimedia telephony, end-to-end packet-switched streaming, multimedia messaging service, and multimedia broadcast /multimedia service. We also review the supporting technologies for those four applications. The article concludes with a discussion of error control and rate control adaptability to network QoS variation, which is distinct from wired networks and critical to wireless networks. With respect to MBMS, we point out that required cell transmission power is crucial when realizing meaningful multicast coverage, and suggest a system that integrates different unicast and multicast networks, application-layer data repair, and transmission scheduling.
Summary
A virus neutralizing test using an indirect immunoperoxidase technique (VNT‐IIP) for rabies has been developed for the titration of dog and cat serum samples in Japan. The VNT‐IIP has the ...advantage that results obtained can be viewed by the naked eye. The purpose of this study was to validate the VNT‐IIP and compare it with one of the international standard methods, the fluorescent antibody virus neutralization test (FAVNT). The VNT‐IIP showed satisfactory repeatability, high analytical specificity and good accuracy. Regarding the comparison between the VNT‐IIP and the FAVNT, the VNT‐IIP showed good agreement (91.9%), high sensitivity (92.8%) as well as specificity (87.0%) and good correlation (r = 0.92). As described above, the validation of the VNT‐IIP was satisfactory and the performances of the test proved to be equivalent to those of an international standard method.
