Experiences with the ns-2 Network Simulator - Explicitly Setting Seeds Considered Harmful

The ns-2 network simulator is one of the most widely used packet network simulators. In version 2.1b9 its old random number generator was replaced by an implementation of MRG32k3a to fix sensitivity to seeds. Due to bad documentation and re-use of old scripts many people still use the old API functions to explicitly set seeds. Unfortunately, this corrupts the correct function of the new generator and can lead to correlated simulation results. This might affect the majority of ns-2 simulation results currently published. We show why this is the case, illustrate possible effects, and how to avoid the problem. 1

Implementació i simulació d'un model d'encaminament per a xarxes de sensors de radiofreqüència i subaquàtiques

Las redes de sensores despiertan un gran interés por parte de la comunidad científica. En esta tesis se describe la implementación de un algorítmo de encaminamiento y su posterior adapatación al medio subacuático.Climent Bayarri, JS. (2010). Implementació i simulació d'un model d'encaminament per a xarxes de sensors de radiofreqüència i subaquàtiques. http://hdl.handle.net/10251/11429Archivo delegad

Simulation and Improvement of the Handover process in IEEE 802.11p based VANETs (Vehicle Ad-hoc NETworks)

Projecte final de carrera fet en col.laboració amb College of Electronics and Information Engineering. Tongji UniversityThis research focuses on the study of the handover process and the di erent simulation environments available in order to generate valid results for the optimization of seamless handover in VANET networks. Handover parameter analysis has been performed and implemented in a application developed in order to batch simulate the process of modifying the selected variables and statistically analyzing the results in order to allow further research on the topic to achieve valid results for VANET handover simulations in a very convenient manner

A PROTOCOL SUITE FOR WIRELESS PERSONAL AREA NETWORKS

A Wireless Personal Area Network (WPAN) is an ad hoc network that consists of devices that surround an individual or an object. Bluetooth® technology is especially suitable for formation of WPANs due to the pervasiveness of devices with Bluetooth® chipsets, its operation in the unlicensed Industrial, Scientific, Medical (ISM) frequency band, and its interference resilience. Bluetooth® technology has great potential to become the de facto standard for communication between heterogeneous devices in WPANs. The piconet, which is the basic Bluetooth® networking unit, utilizes a Master/Slave (MS) configuration that permits only a single master and up to seven active slave devices. This structure limitation prevents Bluetooth® devices from directly participating in larger Mobile Ad Hoc Networks (MANETs) and Wireless Personal Area Networks (WPANs). In order to build larger Bluetooth® topologies, called scatternets, individual piconets must be interconnected. Since each piconet has a unique frequency hopping sequence, piconet interconnections are done by allowing some nodes, called bridges, to participate in more than one piconet. These bridge nodes divide their time between piconets by switching between Frequency Hopping (FH) channels and synchronizing to the piconet\u27s master. In this dissertation we address scatternet formation, routing, and security to make Bluetooth® scatternet communication feasible. We define criteria for efficient scatternet topologies, describe characteristics of different scatternet topology models as well as compare and contrast their properties, classify existing scatternet formation approaches based on the aforementioned models, and propose a distributed scatternet formation algorithm that efficiently forms a scatternet topology and is resilient to node failures. We propose a hybrid routing algorithm, using a bridge link agnostic approach, that provides on-demand discovery of destination devices by their address or by the services that devices provide to their peers, by extending the Service Discovery Protocol (SDP) to scatternets. We also propose a link level security scheme that provides secure communication between adjacent piconet masters, within what we call an Extended Scatternet Neighborhood (ESN)

ANÁLISIS Y COMPRESIÓN DE SEÑALES NEURONALES PARA SU TRANSMISIÓN INALÁMBRICA

Esta tesina ofrece un estudio sobre un sistema para la captación, compresión y transmisión inalámbrica de las señales neuronales, en el que destaca la movilidad que ofrece la transmisión inalámbrica ya que permitirá tanto la realización de experimentos "in-vivo", como el desarrollo de dispositivos implantables sin los inconvenientes del cableado.Traver Sebastiá, L. (2007). ANÁLISIS Y COMPRESIÓN DE SEÑALES NEURONALES PARA SU TRANSMISIÓN INALÁMBRICA. http://hdl.handle.net/10251/12540Archivo delegad