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Cognitive radio and UWB technologies are new radio designs philosophies in order to optimize the spectrum utilization by exploiting the unused and the under-used spectrum in dynamically changing environments. Although the contrasting philosophies of cognitive radio and UWB technology gains can be made by merging these two technologies. In this paper we(More)
Primary signet ring cell carcinoma of the urinary bladder is a rare and aggressive histologic subtype of adenocarcinoma. In general, this tumor occurs in the middle age, and clinical presentation does not differ from transitional cell carcinomas. The prognosis is often poor, given the advanced stage at diagnosis. To our knowledge, <100 cases of signet ring(More)
IEEE 802.11e is a wireless local area networking standard introducing quality of service. It defines new MAC protocols, mainly HCF and EDCF. EDCF is a contention-based channel access scheme and is part of HCF for infrastructure networks and may be used as a separate coordination function for wireless ad-hoc networks. The aim of this paper is to propose a(More)
In Internet, the user's traffic crosses several domains. The users want more and more an end-to-end quality of service (QoS). So it&#146;s necessary to have differentiation mechanisms in the access networks where the bottlenecks are often located. In this paper, we propose a global quality of service management applied to DiffServ environments and IEEE(More)
The Utra Wide Band physical layer specified by the IEEE 802.15.4a standard [1] presents numerous advantages comparing with its original IEEE 802.15.4 standard, namely high accuracy positioning ability, high data rate up to 27 mbps, extended communication range, low power consumption and low complexity. Actually, many research and development activities(More)
Among various types of attacks on an Ethernet network, a "sniffing attack" is probably one of the most difficult attacks to handle. Sniffers are programs that allow a host to capture any packets in an Ethernet network, by putting the host's network interface card (NIC) into the promiscuous mode. When a host's NIC is in the normal mode, it captures only the(More)