Quality of experience (QoE) in multimedia traffic has been the focus of extensive research in the last decade. The estimation of the QoE provides valuable input in order to measure the user satisfaction of a particular service. QoE estimation is challenging as it tries to measure a subjective metric where the user experience depends on a number of factors that cannot simply be measured. In this work, we present a methodology and a system based on fuzzy expert system to estimate the impact of network conditions (QoS) on the QoE of video traffic. At first, we conducted subjective tests to correlate network QoS metrics with participants' perceived QoE of video traffic. Second, we propose a No Reference method based on fuzzy expert system to estimate the network impact on the video QoE. The membership functions of the proposed fuzzy system are derived from normalized probability distributions correlating the QoS metrics with QoE. We propose a simple methodology to build the fuzzy inference rules. We evaluated our system in two different sets of experiments. The estimated video quality showed high correlation with the subjective QoE obtained from the participants in a controlled test. We integrated our system as part of a monitoring tool in an industrial IPTV test bed and compared its output with standard Video Quality Monitoring (VQM). The evaluation results show that the proposed video quality estimation method based on fuzzy expert system can effectively measure the network impact on the QoE.

The service-oriented approach is becoming more and more popular to integrate highly heterogeneous systems. Web services are the natural evolution of conventional middleware technologies to support Web-based and enterpriselevel integration. Formal testing of such Web-based technology is a key point to guarantee its reliability. In this paper, we choose a non-intrusive approach based on monitoring to propose a conformance passive testing methodology to check that a composed Web service respects its functional requirements. This methodology is based on a set of formal invariants representing properties to be tested including data and time constraints. Passive testing of an industrial system (that uses a composition of Web services)is briefly presented to demonstrate the effectiveness of the proposed approach.

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Vehicular Ad-hoc Network (VANET) is among the most relevant forms of mobile ad-hoc networks. VANET helps improving traffic safety and efficiency. By exchanging information between each others, vehicles can warn drivers or even prepare for dangerous situation. These warnings can be about critical situations like vehicles merging in a highway. Detecting and warning about such situations require a reliable communication between vehicles increasing thus the need for an efficient medium access control (MAC) protocol. In this paper, we propose to apply Transmit And Reserve (TAR), an adhoc medium access protocol, to vehicular communications. We integrated TAR into NS-3 simulator and evaluated its performance compared to IEEE 802.11 DCF in a vehicular network context. The evaluation results show that TAR is an efficient medium access protocol for VANET critical situations as it increases the throughput reduces the medium access delays and provides close to optimal short term fairness.