José C. López-Ardao

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Several traffic measurement reports have convincingly shown the presence of self-similarity in modern networks, inducing as a result a revolution in the stochastic modeling of traffic. The use of self-similar processes in performance analysis has opened new problems and research issues in simulation studies, where the efficient generation of synthetic(More)
In last decade, we have seen the first steps to the end of passive television. Thanks to continuous advances in hardware and software, now, Digital TV technology is mature enough to enhance traditional TV sets (limited to content reproduction) with computing capability to run multimedia software integrating richer formats. And a significant example of this(More)
Several recent traffic measurement studies have convincingly shown the presence of self-similarity in modern high-speed networks, involving a very important revolution in the stochastic modeling of traffic. Thus the use of self-similar processes has opened new problems and research fields in network performance analysis, mainly in simulation studies, where(More)
In this paper a general parametric model is proposed which provides estimation for the perceived quality of video, coded with different codecs, at any bit rate and display format. The proposed model takes into account video content, using an objective estimation of the spatial-temporal activity, based on the average SAD (Sum of Absolute Differences) for the(More)
In this paper, we show how the proposed model in ITU-T Recommendation G.1070 "Opinion model for video-telephony applications" cannot model properly the perceptual video quality, especially in the low bit rate range, due to the great variation of MOS values depending on video content. In this work, we present different enhancements to the model, allowing a(More)
In this paper, a parametric model is proposed which provides estimation for the perceived quality of video, coded with different codecs, at any bit rate and display format. The video quality metric used is one of the standardized Full Reference models in Recommendations ITU-T J.144 and ITU-R BT.1683. The proposed model is based on the video quality(More)
Optical Burst Switching is efficient for bursty traffic but also weak in guaranteeing the delivery of real-time traffic. In this paper, we propose to enhance OBS with an OCS-like feature by providing each source-destination pair with a wavelength sharable home circuit. These wavelength sharable home circuits not only provide guaranteed bandwidth for(More)
In this paper we analyze how the frame rate affects the video perceived quality for different video contents. Combining these results with our previous work, a new parametric model is proposed for video quality estimation, including the effects of frame rates, bit rate, display size and video content. The performance of the new proposed model was evaluated(More)