Application of advanced on-board processing concepts to future satellite communications systems: Bibliography

Abstracts are presented of a literature survey of reports concerning the application of signal processing concepts. Approximately 300 references are included

Optical packet networks : enabling innovative switching technologies

Les réseaux informatiques avec une grande capacité nécessitent des liaisons de transmission de données rapides et fiables pour prendre en charge les applications web en pleine croissance. Comme le nombre de serveurs interconnectés et la capacité de stockage des médias ne cessent daugmenter, les communications optiques et les technologies de routage sont devenues intéressantes grâce au taux binaire élevé et à lencombrement minimum offert par la fibre optique. Les réseaux optiques à commutation de paquets (OPSNs) offrent une flexibilité accrue dans la gestion de réseau. OPSNs exploitent les convertisseurs de longueur donde accordables (WC) pour minimiser la probabilité de blocage et fournir une allocation dynamique des longueurs donde. Les émetteurs optiques basés sur des sources multi-longueurs donde se présentent comme une solution intéressante en termes de coût, dencombrement et defficacité énergétique par rapport aux autres types de lasers. Les convertisseurs de longueurs donde doivent permettre des taux binaires élevés et une transparence à une grande variété de formats de modulation, tout en offrant une réponse rapide, des niveaux de puissance modérés et un rapport de signal à bruit optique (OSNR) acceptable à la sortie. Plusieurs technologies de conversion de longueur donde ont été proposées dans la littérature. Lutilisation du mélange à quatre ondes (FWM) dans les amplificateurs optiques à semi-conducteurs (SOA) permet lutilisation de faibles niveaux de puissance dentrée et offre une bonne efficacité de conversion ainsi que la possibilité dintégration photonique. Les SOAs offrent donc un excellent compromis par rapport aux autres solutions. Pour couvrir une plus large bande de conversion, nous utilisons le schéma exploitant le FWM avec doubles pompes dans les SOAs. Pour la stabilité de phase, les pompes viennent d’un laser en mode bloqué (QDMLL) qui sert comme source multi-longueurs donde. Deux modes du QDMLL sont sélectionnés par un filtrage accordable et servent comme doubles pompes. Un filtre accordable placé à la sortie du SOA sert à sélectionner le produit du FWM pour le signal final. Nous étudions le convertisseur de longueur donde proposé et comparons sa performance pour différents formats de modulation (modulation dintensité et de phase) et à différents débits binaires (10 et 40 Gbit/s). Le taux derreur binaire, lefficacité de conversion et la mesure de lOSNR sont présentés. Nous démontrons aussi la possibilité de simultanément convertir en longueurs donde les données et l’étiquette. Les données à haut débit et l’étiquette à faible débit se retrouvent dans une seule bande de longueurs d’onde, et ils sont convertis ensemble avec une bonne efficacité. Notre démonstration se concentre sur les performances de conversion, donc les données et létiquette sont des signaux continus plutôt que de paquets optiques. Des mesures de taux derreur binaire ont été effectuées à la fois pour les données et pour létiquette. Nous proposons aussi lutilisation de QDMLL comme source de transmetteurs WDM pour deux applications différentes: unicast et multicast. Nous démontrons aussi sa compatibilité avec le format de transmission DQPSK à haut débit binaire. Nous évaluons la performance du DQPSK en terme de taux derreur binaire et comparons sa performance à celle dune source laser à cavité externe.Large scale computer networks require fast and reliable data links in order to support growing web applications. As the number of interconnected servers and storage media increases, optical communications and routing technologies become interesting because of the high speed and small footprint of optical fiber links. Furthermore, optical packet switched networks (OPSN) provide increased flexibility in network management. Future networks are envisaged to be wavelength dependent routing, therefore OPSN will exploit tunable wavelength converters (WC) to enable contention resolution, reduce wavelength blocking in wavelength routing and switching, and provide dynamic wavelength assignment. Optical transmitters based on multi-wavelength sources are presented as an attrative solution compared to a set of single distributed feedback lasers in terms of cost, footprint and power consumption. Wavelength converters should support high bit rates and a variety of signal formats, have fast setup time, moderate input power levels and high optical signal-to-noise ratio at the output. Several wavelength conversion technologies have been demonstrated. The use of four wave mixing (FWM) in semiconductor optical amplifiers (SOAs) provides low input power levels, acceptable conversion efficiency and the possibility of photonic integration. SOAs therefore offer excellent trade-offs compared to other solutions. To achieve wide wavelength coverage and integrability, we use a dual pump scheme exploiting four-wave mixing in semiconductor optical amplifiers. For phase stability, we use a quantum-dash mode-locked laser (QD-MLL) as a multi-wavelength source for the dual pumps, with tunability provided by the frequency selective filter. We investigate the proposed wavelength converter and compare its performance of wavelength conversion for different non-return-to-zero (NRZ) intensity and phase modulation formats at different bit rates (10 and 40 Gbit/s). Bit error rate, conversion efficiency and optical signal-to-noise ratio measurements are reported. We demonstrate the possibility of tightly packed payload and label wavelength conversion at very high data baud rate over wide tuning range with good conversion efficiency. Our demonstration concentrates on conversion performance, hence continuous payload and label signals were used without gating into packets. Bit error measurements for both payload and label were performed. We propose the use of QD-MLL as multi-wavelength source for WDM unicast and multicast applications and we investigated its compatibility with DQPSK transmission at high bit rate. We quantify DQPSK performance via bit error rate measurements and compare performance to that of an external cavity laser (ECL) source

End-to-end quality of service provisioning in multilayer and multidomain environments

Tesis doctoral inédita. Universidad Autónoma de Madrid, Escuela Politécnica Superior, marzo de 200

Physical Agents

This chapter reviews different approaches for the development of new models, architectures and real applications of physical agents. The chapter starts by identifying this kind of agents and their main requirements. After that, it presents one approach to allow deliberation while the world changes, and some specific applications that have been implemented by different participants of the AgentCities.ES network: a multi-agent system architecture to control a single robot, a submarine robot, and a container terminal management system for the port of Valencia

Ecological characterization of the Florida springs coast: Pithlachascotee to Waccasassa Rivers

This report covers the upper coast of west-central Florida. This region includes the drainage basins and nearshore waters of the west coast of Florida between, but not including, the Anclote River basin and the Suwannee River basin. The name Springs Coast wash chosen because this area contains a multitude of springs, both named and too small or inaccessible to have been names. Much of the area is karstic limestone. Most recognizable among the springs are the famous Crystal river, Weeki Wachee, and Homosassa. This territory includes large expanses of marsh and wetland and, along its shores, the southern end of the largest area of seagrass beds in the state -- the Florida Big Bend Seagrass Beds preserve. It also possesses numerous spring-fed rivers and streams along the coast, whose constant discharges provide unique, relatively stable estuarine environments. This document is a summary of the available information on the Springs Coast area of Florida, for use by planners, developers, regulatory authorities, and other interested parties. An understanding of the factors affecting their plans and the possibly unexpected impacts of their actions on others will, it is hoped, promote intelligent development in areas capable of supporting it. We have tried to provide a clear, coherent picture of what is currently known about how the physical, chemical, and biological factors of the environment interact. (343 pp.

International VLBI Service for Geodesy and Astrometry 2014 Annual Report

IVS is an international collaboration of organizations which operate or support Very Long Baseline Interferometry (VLBI) components. The goals are: 1. To provide a service to support geodetic, geophysical and astrometric research and operational activities. 2. To promote research and development activities in all aspects of the geodetic and astrometric VLBI technique. 3. To interact with the community of users of VLBI products and to integrate VLBI into a global Earth observing system

Rendimiento de TCP y Cálculo de Rutas en Redes de Conmutación Óptica de Ráfagas

La tecnología de conmutación óptica de ráfagas (Optical Burst Switching, OBS) es una alternativa prometedora para la próxima generación de redes ópticas. Esta tesis estudia el comportamiento de flujos de datos que empleen el protocolo de transporte TCP (Transmission Control Protocol) sobre una red basada en la mencionada tecnología OBS. Así, la tesis estudia el impacto del asentimiento retardado en OBS, propone un modelo teórico que captura el funcionamiento de TCP sobre OBS con múltiples flujos y estudia el efecto de la sincronización de flujos TCP en una red OBS. Además, la tesis propone una técnica de encaminamiento adaptativa y multicamino para OBS, y diseña e implementa un elemento de cálculo de rutas basado en PCE (Path Computation Element) para redes de conmutación de ráfagas OBS con encaminamiento por longitud de onda, conocidas como WR-OBS (Wavelength-Routed OBS).Departamento de Teoría de la Señal y Comunicaciones e Ingeniería Telemátic

Towards a machine enabled semantic framework for the distributed engineering design

The overall aim of this thesis is to identify and propose a suitable architectural framework for supporting cooperation processes and therefore enabling semantics within the distributed engineering design environment. The proposed architecture is intended to\ud characterize a software-based management of design related data, information and knowledge flows in the distributed engineering design organization. The aim is to provide a computational context for implementing ICT tools that would: (i) Minimise the effect of user and resource dispersion (particularly temporal and geographical dispersion), the misunderstandings that might be generated by the\ud (otherwise beneficial) functional and semantic distribution, the time spent for searching and retrieval of information, the effort of information translation between different tools and the administrational and organisational efforts not directly related to the design process (e.g. revision control) (ii) Maximise the quality of information (i.e. relevant information at relevant and appropriate times), knowledge sharing and reuse among distributed design\ud actors, the flexibility of the user interfaces and the designer’s time spent in the actual designing process.\ud In order to achieve the overall aim, the research work supporting this thesis was carried out along the following objectives:\ud 1. To investigate and characterize the engineering design process performed in a distributed environment and its problematic aspects;\ud 2. To research and study alternative theories for thinking and modelling the distributed engineering design process;\ud 3. To investigate current research in information and knowledge management for identifying supporting technologies for a possible solution to the identified\ud problematic aspects (from point 1);\ud 4. To analyze the requirement needs for a solution according to the findings from previous objectives, i.e. the driving problems (from point 1), the research and\ud therefore the thinking approach (from point 2), and available supporting technologies (from point 3);\ud 5. To synthesize the architectural framework along the identified supporting technologies (from point 3);\ud 6. To instantiate a software system along the underlying computational context as described by the architectural framework (from point 5)