Arrayed Waveguide Grating-Based Interrogation System for Safety Applications and High-Speed Measurements

This thesis is focused on the design of two interrogation systems for Fiber Bragg Grating (FBG) sensors based on the Wavelength Domain Multiplexing (WDM) by means of the Arrayed Waveguide Grating (AWG) device. The FBG sensors have been employed in a large number of environments thanks to their intrinsic characteristics. To design a measurement system based on the Fiber Optic Sensor (FOS) technology, it is mandatory to make use of an optoelectronic system with the aim to "read" the wavelength shifting performed by the sensors. This latter is named interrogation system and, actually, sets a limit on the employability of the FBG sensors, due to its cost, design complexity and low reliability in some contests. For this reasons, the researchers are constantly looking on new technologies for the design of innovative interrogation systems. The AWG device seems to provide characteristics which cannot be reached with other devices and, due to its passivity, gives the possibility to increase the system speed to let the FBG sensors to be employed also for the detection of high-speed phenomena. Furthermore, thanks to the robustness and reliability of AWG device, is possible to turn an interrogation system into a full analog monitoring system employable in a safety scenario, such as industrial processes or other kind of environments, in which digital processing does not ensure enough reliability

Conception pour la testabilité des systèmes biomédicaux implantables

Architecture générale des systèmes implantables -- Principes de stimulation électrique -- Champs d'application des systèmes implantables -- Les particularités des circuits implantables -- Tendance future -- Conception pour la testabilité de la partie numérique des circuits implantables -- "Desigh and realization of an accurate built-in current sensor for Iddq testing and power dissipation measurement -- Conception pour la testabilité de la partie analogique des circuits implantables -- BIST for digital-to-analog and Analogo-to-digital converters -- Efficient and accurate testing of analog-to-digital converters using oscillation test method -- Design for testability of Embedded integrated operational amplifiers -- Vérification des interfaces bioélectroniques des systèmes implantables -- Monitorin the electrode and lead failures in implanted microstimulators and sensors -- Capteurs de température intégrés pour la vérification de l'état thermique des puces dédiées -- Built-in temperature sensors for on-line thermal monitoring of microelectronic structures -- Un protocole de communication fiable pour la programmation et la télémétrie des système implantables -- A reliable communication protoco for externally controlled biomedical implanted devices

The Global Navigation System Scope (GNSScope): a toolbox for the end-to-end modelling simulation and analysis of GNSS

The thesis provides a detailed overview of the work carried out by the author over the course of the research for the award of the degree of Doctor of Philosophy at the University of Westminster, and the performance results of the novel techniques introduced into the literature. The outcome of the work is collectively referred to as the Global Navigation System Scope (GNSScope) Toolbox, offering a complete, fully reconfigurable platform for the end-to-end modeling, simulation and analysis of satellite navigation signals and systems, covering the signal acquisition, tracking, and range processing operations that take place in a generic Global Navigation Satellite System (GNSS) receiver, accompanied by a Graphical User Interface (GUI) providing access to all the techniques available in the toolbox. Designed and implemented entirely in the MATLAB mathematical programming environment using Software Defined Radio (SDR) receiver techniques, the toolbox offers a novel new acquisition algorithm capable of handling all Phase-Shift Keying (PSK) type modulations used on all frequency bands in currently available satellite navigation signals, including all sub-classes of the Binary Offset Carrier (BOC) modulated signals. In order to be able to process all these signals identified by the acquisition search, a novel tracking algorithm was also designed and implemented into the toolbox to track and decode all acquired satellite signals, including those currently intended to be used in future navigation systems, such as the Galileo test signals transmitted by the GIOVE satellites orbiting the Earth. In addition to the developed receiver toolbox, three novel algorithms were also designed to handle weak signals, multipath, and multiple access interference in GNSScope. The Mirrored Channel Mitigation Technique, based on the successive and parallel interference cancellation techniques, reduces the hardware complexity of the interference mitigation process by utilizing the local code and carrier replicas generated in the tracking channels, resulting in a reduction in hardware resources proportional to the number of received strong signals. The Trigonometric Interference Cancellation Technique, used in cross-correlation interference mitigation, exploits the underlying mathematical expressions to simplify the interference removal process, resulting in reduced complexity and execution times by reducing the number of operations by 25% per tracking channel. The Split Chip Summation Technique, based on the binary valued signal modulation compression technique, enhances the amount of information captured from compressing the signal to reveal specific filtering effects on the positive and negative polarity chips of the spreading code. Simulation case studies generated entirely using the GNSScope toolbox will be used throughout the thesis to demonstrate the effectiveness of the novel techniques developed over the course of the research, and the results will be compared to those obtained from other techniques reported in the literature

An Optical Grooming Switch for High-Speed Traffic Aggregation in Time, Space and Wavelength

In this book a novel optical switch is designed, developed, and tested. The switch integrates optical switching, transparent traffic aggregation/grooming, and optical regener-ation. Innovative switch subsystems are developed that enable these functionalities, including all-optical OTDM-to-WDM converters. High capacity ring interconnection between metro-core rings, carrying 130 Gbit/s OTDM traffic, and metro-access rings carring 43 Gbit/s WDM traffic is experimentally demonstrated. The developed switch features flexibility in bandwidth provisioning, scalability to higher traffic volumes, and backward compatibility with existing network implementations in a future-proof way

Toward Brain Area Sensor Wireless Network

RÉSUMÉ De nouvelles approches d'interfaçage neuronal de haute performance sont requises pour les interfaces cerveau-machine (BMI) actuelles. Cela nécessite des capacités d'enregistrement/stimulation performantes en termes de vitesse, qualité et quantité, c’est à dire une bande passante à fréquence plus élevée, une résolution spatiale, un signal sur bruit et une zone plus large pour l'interface avec le cortex cérébral. Dans ce mémoire, nous parlons de l'idée générale proposant une méthode d'interfaçage neuronal qui, en comparaison avec l'électroencéphalographie (EEG), l'électrocorticographie (ECoG) et les méthodes d'interfaçage intracortical conventionnelles à une seule unité, offre de meilleures caractéristiques pour implémenter des IMC plus performants. Les avantages de la nouvelle approche sont 1) une résolution spatiale plus élevée - en dessous dumillimètre, et une qualité de signal plus élevée - en termes de rapport signal sur bruit et de contenu fréquentiel - comparé aux méthodes EEG et ECoG; 2) un caractère moins invasif que l'ECoG où l'enlèvement du crâne sous une opération d'enregistrement / stimulation est nécessaire; 3) une plus grande faisabilité de la libre circulation du patient à l'étude - par rapport aux deux méthodes EEG et ECoG où de nombreux fils sont connectés au patient en cours d'opération; 4) une utilisation à long terme puisque l'interface implantable est sans fil - par rapport aux deux méthodes EEG et ECoG qui offrent des temps limités de fonctionnement. Nous présentons l'architecture d'un réseau sans fil de microsystèmes implantables, que nous appelons Brain Area Sensor NETwork (Brain-ASNET). Il y a deux défis principaux dans la réalisation du projet Brain-ASNET. 1) la conception et la mise en oeuvre d'un émetteur-récepteur RF de faible consommation compatible avec la puce de capteurs de réseau implantable, et, 2) la conception d'un protocole de réseau de capteurs sans fil (WSN) ad-hoc économe en énergie. Dans ce mémoire, nous présentons un protocole de réseau ad-hoc économe en énergie pour le réseau désiré, ainsi qu'un procédé pour surmonter le problème de la longueur de paquet variable causé par le processus de remplissage de bit dans le protocole HDLC standard. Le protocole adhoc proposé conçu pour Brain-ASNET présente une meilleure efficacité énergétique par rapport aux protocoles standards tels que ZigBee, Bluetooth et Wi-Fi ainsi que des protocoles ad-hoc de pointe. Le protocole a été conçu et testé par MATLAB et Simulink.----------ABSTRACT New high-performance neural interfacing approaches are demanded for today’s Brain-Machine Interfaces (BMI). This requires high-performance recording/stimulation capabilities in terms of speed, quality, and quantity, i.e. higher frequency bandwidth, spatial resolution, signal-to-noise, and wider area to interface with the cerebral cortex. In this thesis, we talk about the general proposed idea of a neural interfacing method which in comparison with Electroencephalography (EEG), Electrocorticography (ECoG), and, conventional Single-Unit Intracortical neural interfacing methods offers better features to implement higher-performance BMIs. The new approach advantages are 1) higher spatial resolution – down to sub-millimeter, and higher signal quality − in terms of signal-to-noise ratio and frequency content − compared to both EEG and ECoG methods. 2) being less invasive than ECoG where skull removal Under recording/stimulation surgery is required. 3) higher feasibility of freely movement of patient under study − compared to both EEG and ECoG methods where lots of wires are connected to the patient under operation. 4) long-term usage as the implantable interface is wireless − compared to both EEG and ECoG methods where it is practical for only a limited time under operation. We present the architecture of a wireless network of implantable microsystems, which we call it Brain Area Sensor NETwork (Brain-ASNET). There are two main challenges in realization of the proposed Brain-ASNET. 1) design and implementation of power-hungry RF transceiver of the implantable network sensors' chip, and, 2) design of an energy-efficient ad-hoc Wireless Sensor Network (WSN) protocol. In this thesis, we introduce an energy-efficient ad-hoc network protocol for the desired network, along with a method to overcome the issue of variable packet length caused by bit stuffing process in standard HDLC protocol. The proposed ad-hoc protocol designed for Brain-ASNET shows better energy-efficiency compared to standard protocols like ZigBee, Bluetooth, and Wi-Fi as well as state-of-the-art ad-hoc protocols. The protocol was designed and tested by MATLAB and Simulink

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Next generation technologies for 100 Gb/s PON systems

The worldwide explosion of Internet traffic demand is driving the research for innovative solutions in many aspects of the telecommunication world. In access systems, passive optical networks (PONs) are becoming the preferred solution towards which most providers are migrating thanks to the unrivalled bandwidth they can offer. PON systems with a capacity of 100 Gb/s are envisioned as the solution to the dramatic increase in bandwidth and will be essential to support the future fixed and mobile broadband services. However, many challenging aspects have to be addressed in order to overcome the limitations imposed by the physical layer while meeting the economical requirements for mass deployment. In this thesis a comprehensive approach is taken in order to address the most compelling problems and investigate a series of solutions to the current capacity limitations of PONs. Advanced modulation formats are used to achieve bit-rate enhancement from 10 Gb/s to 25 Gb/s re-using the same optoelectronic devices in order to provide a 2.5x increase in transmission speed without resorting to a newer, more expensive generation of higher speed devices. The management of chromatic dispersion is also addressed in order to extend the reach of the networks beyond the standard 20 km using either electronic or optical based compensation strategies. Transmission of 25 Gb/s traffic over fibre lengths of 40 and 50 km is demonstrated confirming the suitability of the proposed technologies for extended reach networks which could greatly reduce the number of existing nodes and hence the capital and operational costs of PONs. Optical amplification strategies are also discussed as a means to improve the physical reach of the networks, both in terms of distance and number of customers. Raman amplifiers and semiconductor optical amplifiers are investigated in order to extend the reach of a PON upstream channel. The results demonstrate a reach of up to 50 km which is more than double the typical fibre length of 20 km adopted in deployed systems today. A number of customers, up to 512, was also demonstrated in a 20 km network, increased from the typical 32 or 64 users of most commercial networks