Samir Mohamed

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This paper addresses the problem of quantitatively evaluating the quality of a speech stream transported over the Internet as perceived by the end-user. We propose an approach being able to perform this task automatically and, if necessary, in real time. Our method is based on using G-networks (open networks of queues with positive and negative customers)(More)
An important and unsolved problem today is the automatic quantification of the quality of video flows transmitted over packet networks. In particular, the ability to perform this task in real time (typically for streams sent themselves in real time) is specially interesting. The problem is still unsolved because there are many parameters affecting video(More)
We have recently proposed a novel, non–intrusive, real– time approach to measuring the quality of an audio (or speech) stream transmitted over a packet network. The proposed approach takes into account the diversity of the factors which affect audio quality, including encoding parameters and network impairments. The goal of this method is to overcome the(More)
There is a great demand to assess video quality transmitted in real time over packet networks, and to make this assessment in real time too. Quality assessment i s a c hieved using two types of methods: objective or subjective. Subjective methods give more reliable results than objective methods; the latter do not always correlate well with human(More)
The goal of this paper is to show how Artificial Neural Networks (ANNs) can be used to mimic the way human subjects estimate the quality of audio signals when distorted by changes in several parameters that affect the transmitted audio quality. To validate the approach, we carried out the subjective quality experiment for speech signals distorted by(More)
Natural immune system (NIS) provides a rich source of inspiration for computer security in the age of the Internet. The Artificial Immune System (AIS) is one of the promising techniques that seek to capture some aspects of the natural immune system. One of the major algorithms to implement the AIS is the Negative Selection (NS) algorithm. The paper proposes(More)