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The enhanced distributed channel access (EDCA) mechanism of the IEEE 802.11e standard provides quality-of-service (QoS) support through service differentiation by using different medium-access-control (MAC) parameters for different stations. The configuration of these parameters, however, is still an open research challenge, as the standard provides only a set of fixed recommended values that do not take into account the current wireless local area network (WLAN) conditions and, therefore, lead to suboptimal performance.
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Peer-to-peer (P2P) networking is based on a distributed application architecture that covers a diverse set of network types. In pure P2P overlays, every node in the network acts as a "servent", they act as a server and a client simultaneously. Highlighting the fact that there is a lack of any centralised control, acting all nodes as equals. This networks have become very popular in the form of file-sharing networks. It is based on the idea of sharing any type of resources between all nodes. Peers are both suppliers and consumers of resources.
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Wireless Mesh Networks (WMNs) are seen as a means to provide last mile connections in Next Generation Networks (NGNs). Because of their auto configuration capabilities and the low deployment cost WMNs are considered to be an efficient solution for the support of multiple voice, video and data services in NGNs. This paper looks at the optimal provision of resources in WMNs for Voice over IP (VoIP) traffic, which has strict performance require ments in terms of delay, jitter and packet loss.
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Wireless Mesh Networks (WMNs) which can be integrated to other types of networks at a reasonable cost are good candidates to facilitate the efficient and flexible deployment of Next Generation Networks (NGNs). Due to the widespread presence of IEEE 802.11Wireless Local Area Networks (WLANs) most of current WMNs are based on this technology. However, IEEE 802.11 is primarly designed for one-hop networks and its random access protocol (CSMA/CA) is problematic in multi-hop environments due to collisions, which decrease efficiency and service quality.
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Many modern devices come with several, heterogeneous, network interface cards (NICs). However, simple operations like transferring data flows to the cheapest NIC or to one with enough Quality of Service (QoS) are awkward tasks on most Operating Systems. In this paper, we discuss the criteria to select the proper NIC for a given data flow. We also present a new Operating System service, called netqos, to publish data and figures of merit for these criteria.
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Admission control algorithms must ensure that, when a new QoS resource reservation is accepted, reservations already present in the system continue having their QoS guarantees honored. In this paper we consider different approaches to compute the aggregated allocated capacity in WiMAX networks and, based on their limitations, propose the EDiophantine solution. The mathematical foundations for the designed approach are provided along with the performance improvements to be expected, both in accuracy and computational terms, as compared to three alternatives of increasing complexity.
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Esta tesis doctoral se enmarca dentro del área de investigación de la seguridad en entornos Peer-to-Peer (P2P) totalmente descentralizados (también denominados puros.) En particular, el objetivo principal de esta tesis doctoral es definir, analizar e implementar un esquema para la distribución segura de los contenidos compartidos. En este trabajo de tesis se han realizado importantes avances e innovadoras aportaciones enfocadas a garantizar que el contenido compartido es auténtico; es decir, que no ha sido alterado, incluso tratándose de una réplica del original.
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En el presente Proyecto se pretende realizar un prototipo para realizar medidas en tiempo real de diferentes parámetros que determinan la calidad del agua. Para ello se seleccionaron 3 sensores que medirán respectivamente cantidad de oxígeno disuelto, cantidad de carbono y la conductividad del agua. Para poder realizar el estudio se deberá efectuar el montaje eléctrico entre los sensores y los módulos y terminales que controlan dichos sensores, además será necesario realizar la conexión puerto-serie entre dichos terminales y el ordenador.
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Wireless mesh networking is a promising, cost effective and efficient technology for realizing backhaul networks supporting high quality services. In such networks, multicast data are transmitted blindly without any mechanism protecting data from loss, ensuring data reception, and optimizing channel allocation. The multicast services may undergo, then, very high data loss ratio which is exacerbated with the number of hops. In this paper, we propose a Reliable Multicast Distribution System (RMDS) to optimize multicast packets transmission in bridged networks.
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Final degree project on the University CARLOS III of Madrid, supervised by Dr. Albert Banchs, department of telematics. Graduation of Technical Engineer of Telecommunications Specialized on Image and Sound. Subject-matter is the data storage from PLC. A Programmable Logic Controller (PLC) is a computer that is specially designed for precess controlling. For example cooling down the temperature in a room is a process. Keeping this temperature constant at a desired temperature (e.g. -18°C) over time is a process control.
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