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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
311

Estudo de esquemas de amplificação para redes PON de longo alcance / Study amplification schemes for long reach PON networks

Paiva, Getúlio Eduardo Rodrigues de 12 April 2012 (has links)
O surgimento de novos serviços que requerem uma largura de banda cada vez maior, bem como o crescente número de usuários de tais serviços, têm introduzido desafios às empresas operadoras de telecomunicações em sua capacidade de atender a estas demandas sem perda apreciável da qualidade de serviço e mantendo, ainda assim, os custos num nível aceitável pelos usuários. Neste contexto, redes ópticas passivas (PONs) vêm atraindo grande interesse em anos recentes. Na sua variante de longo-alcance, as redes PON permitem uma consolidação do uso dos equipamentos e centrais de serviço requeridos, reduzindo custos operacionais e de instalação. Uma das formas de atingir este maior alcance dá-se por meio da inserção de amplificadores ópticos nas redes de acesso. Neste trabalho, portanto, estudaram-se alguns tipos de amplificadores ópticos e suas possíveis aplicações em redes de acesso, levando a topologias de longo alcance e alta capacidade. Foram realizadas avaliações experimentais de um extensor, baseado em amplificadores ópticos semicondutores (SOAs), na rede GPON do CPqD, sob a Meta 3 do Projeto GIGA, possibilitando a obtenção de uma topologia do tipo Fiber-to-the-Building (FTTB) com 80 km de extensão e 128 usuários atendidos por uma única central de serviço. Além dessas validações experimentais, foram simulados computacionalmente SOAs com características otimizadas bem como sistemas que utilizam fibras dopadas com érbio bombeadas remotamente, sendo que nestes últimos, atingiram-se distâncias superiores a 100 km. / The emergence of new services which require an increasing bandwidth, as well as the growing number of users of such services, have introduced challenges to the network operators in regard to their capacity of supporting these demands with no penalty on the required quality of service, while keeping the costs at an acceptable level for the users. In this context, passive optical networks (PONs) have attracted a great deal of interest in recent years. In the long-reach configuration, PON networks allow for a consolidation of equipament usage, reducing operational and installation costs. One way to achieve this longer reach is by the insertion of optical amplifiers in the access network. Therefore, in our work, we have investigated several optical amplifier configurations, as well as their application in access networks, leading to longreach and high capacity network topologies. Experimental evaluations of an extender, based on semiconductor optical amplifiers, were carried out in the CPqD GPON network, under Goal 3 of GIGA Project, allowing the achievement of a Fiber-to-the-Building (FTTB) topology with 80km of extension and 128 users served by a single central office. Besides these experimental validations, were simulated computationally SOAs with optimized characteristics as well as systems using remotely pumped erbium-doped fibers, whereas in the latter were reached distances exceeding 100 km.
312

inSOA: uma linguagem de composição de serviços para dispositivos móveis

Barcelos, Giovane Oliveira de 19 February 2009 (has links)
Made available in DSpace on 2015-03-05T14:01:20Z (GMT). No. of bitstreams: 0 Previous issue date: 19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Composição de serviços em dispositivos móveis está se tornando indispensável para as atuais e futuras necessidades dos usuários de TI. Estas necessidades são suportadas pela convergência de arquiteturas centralizadas para arquiteturas distribuídas que estimulam a composição de serviços web. Estes serviços web, motivados pela arquitetura Web Services, logo evoluíram para SOA. Esta arquitetura por sua vez, no contexto de orquestração de serviços, tem exigido linguagens de composição para sua efetiva implementação. Linguagens estas, que têm progredido para linguagens interpretadas e declarativas. Neste contexto de evolução, este trabalho apresenta, uma linguagem declarativa de composição de serviços chamada inSOA. Esta linguagem foi desenvolvida para ser executada em dispositivos móveis como parte de um projeto de uma arquitetura ubíqua colaborativa chamada de U-SOA. inSOA é uma solução focada em Web Services com vocação SOA e aderente aos patterns de composição de serviços, além de poder ser embutida em lin / Services composition on mobile devices is becoming essential for current and future needs of IT users. These needs are supported by the convergence from centralized to distributed architectures that encourage the web services composition. These web services, motivated by the Web Services architecture, soon evolved into an SOA. This architecture in turn, in the services orchestration, has required composition language for their effective implementation. These languages, has advanced to interpreted and declarative languages. In this evolution context, this work presents, a declarative language of services composition services called inSOA. This language was developed to execute on mobile devices as part of a project of a collaborative ubiquitous architecture called USOA. InSOA is a solution focused on Web Services and SOA adherent to the patterns of services composition, and can be embedded in a language of general purpose and light in the better DSL languages style. As a way to test and evaluate the langu
313

Open Source Enterprise Service Bus : Analyzing impact and value in a large organization

Bagherinia, Sharareh January 2013 (has links)
System integration is a challenging task for large organizations since they must manage complex IT infrastructures, and utilize hundreds of applications that cause a myriad of complications as a result of rapidly evolving systems and technologies. Over time customer requirements and the automation of internal business functions forced the gigantic service providers to develop and buy applications for different purposes. Not many years before, the applications in an organization were usually separated silos, specifically designed to answer a particular problem. However, this way of working was not efficient. It is not impossible to design one application that runs the total business, however, in reality it can't respond to all the needs inside an organization. In most cases the applications need to interact with each other and to reuse functionalities or data. At this point the concept of integrating systems first came to existence.The progress in computer science and information technology has also affected the way that integration between applications was developed and designed over the years. This shows that there's always some new method that should be studied and investigated. In recent years, the Enterprise Service Bus has come to the market and there are many vendors in the market claiming that they have produced the exact solution needed for requirements of organizations.In this work, the attempt was to construct an understanding of the Enterprise Application Integration practices and methods which have been utilized over the years. Mixed methods research a combination of interviews and questionnaire, and Design Science Research methods were used to generate empirical results. While the first two methods was used to supply the input for challenges of system integration, the DSR build and evaluate method was employed to test the ESB product. The criteria for the test were developed mostly as the outcome of interviews and the questionnaire as the main challenge. The aim was to verify efficiency and effectiveness of the selected and proposed ESB under special designed DSR build and evaluate phases.As a result of both theoretical and empirical studies in combination with selection of different methods in Information System research, the work presents a knowledge foundation for organizations with the aim to make a change in their current system integration practices and patterns utilizing approaches facilitated by ESB products.
314

Metodología para la gestión integral de los procesos de producción: modelado de la maquinaria industrial como un sistema de gestión de procesos de negocio

Gilart Iglesias, Virgilio 26 March 2010 (has links)
No description available.
315

Modelo de prestación de servicios ITS de valor agregado: aplicación a los sistemas de gestión de aparcamiento

Herrera Quintero, Luis Felipe 01 April 2011 (has links)
La presente tesis propone un modelo para la prestación de servicios de valor agregado en el ámbito de los Sistemas Inteligentes de Transporte (Intelligent Transportation Systems -ITS) dando solución a los problemas de integración, interoperabilidad, compatibilidad y escalabilidad provocados por la gran cantidad de tecnologías que componen el escenario de los ITS. / Con el fin de integrar todos los elementos que componen los sistemas ITS, el modelo propuesto se basa en las Arquitecturas Orientadas a Servicios (Services Oriented Architecture -SOA) ya que es una solución altamente exitosa en el contexto de las tecnologías de la información y que en otros ámbitos ha contribuido a la prestación de servicios. / Las principales aportaciones del trabajo de investigación son: la creación de un modelo para la prestación de servicios ITS de valor agregado; la creación de un nuevo concepto para la unidad de carretera (Roadside Unit -RSU) la cual integra el paradigma SOA para ofrecer sus funcionalidades en un esquema basado en servicios (Roadside Unit as a Service -RSUAAS); la creación de un catálogo que relaciona las tecnologías y los servicios ITS y que sirve de elemento fundamental para lograr la especialización de los fabricantes; La creación de una arquitectura que aprovecha las ventajas del esquema orientado a servicios para ofrecer servicios de valor agregado al usuario ITS a partir de las tecnologías.
316

AQUEOUS PHOTOCHEMISTRY OF 2-OXOCARBOXYLIC ACIDS

Eugene, Alexis 01 January 2018 (has links)
Atmospheric aerosols affect climate change by altering the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosol (SOA) from gas phase precursors is relatively well understood, it does not account for the abundance of SOA observed during field measurements. Recently it has become apparent that in-aerosol aqueous chemical reactions likely provide some of the missing sources of SOA production, and many studies of aqueous phase processes are underway. This work explores the fates of the simplest 2-oxocarboxylic acids, glyoxylic acid (GA) and pyruvic acid (PA), under simulated solar irradiation in the aqueous phase. Field measurements have revealed that mono-, di-, and oxocarboxylic acids are abundant species present in atmospheric waters. Of particular interest are 2-oxocarboxylic acids because their conjugated carbonyl moieties result in significant UV-visible absorption above 300 nm, allowing absorption of sunlight in the lower troposphere, thereby initiating radical photochemistry and leading to formation of SOA. In Chapter 2 of this work, GA is demonstrated to primarily undergo α-cleavage, producing CO, CO2, formic acid, and the key SOA precursor glyoxal. Trace amounts of oxalic acid and tartaric acid are also quantified. Additionally, the dark thermal aging of glyoxylic acid photoproducts, studied by UV-visible and fluorescence spectroscopies, reveals that the optical properties of the solutions are altered radically by the glyoxal produced. The optical properties display periodicity during photolytic-dark cycles, reflecting behavior expected for aerosols during nighttime and daytime cycles. In contrast, Chapter 3 shows that PA photoreacts via a proton-coupled electron transfer (PCET) mechanism that produces CO2 and organic acids of increased complexity with 6 to 8 carbons. A combination of analytical techniques including 1H and 13C NMR; 13C gCOSY NMR; mass spectrometry; chromatography; and isotope substitutions allows the organic products to be identified as: 2,3-dimethyltartaric acid; 2-hydroxy-2-((3-oxobutan-2-yl)oxy)propanoic acid; and the quasi-intermediate 2-(1-carboxy-1-hydroxyethoxy)-2-methyl-3-oxobutanoic acid. In Chapter 4, PA irradiation is also shown to consume dissolved oxygen so fast that solutions become depleted within a few minutes depending on reaction conditions. This fast process directly produces the atmospheric oxidant singlet oxygen, which enhances the oxidizing capacity of the atmosphere. Additionally, PA photochemistry only proceeds under very acidic conditions (pH ≤ 3.5), like those in most atmospheric aerosols. Finally, we require a thorough understanding of the behavior of 2-oxocarboxylic acids at the air-water interface of aerosols because much of the GA and PA present in the atmosphere is produced in the gas phase and needs to partition into the aqueous phase to undergo photoreaction. Therefore, Chapter 5 uses surface sensitive online electrospray ionization mass spectrometry (OESI-MS) to demonstrate that carboxylic acids delivered from the gas phase onto the surface of aqueous microdroplets display enhanced acidities relative to bulk water solutions. This work demonstrates that aqueous photolysis is a very competitive atmospheric fate for both GA and PA. It also shows that these photoreactions are capable of contributing substantially to SOA formation by building chemical complexity and forming oxidants directly.
317

Lumiere lente et rapide dans les amplificateurs optiques a semi-conducteurs pour des applications en optique micro-onde et aux radar.

Berger, Perrine 20 February 2012 (has links) (PDF)
Les techniques permettant de maitriser la vitesse de la lumière, au-delà de l'intérêt scientifique qu'elles suscitent, peuvent être appliquées au domaine radar. Elles permettent, ainsi, de remplacer avantageusement les retards optiques, jusqu'alors réalisés par des modifications géométriques du chemin optique. L'objectif de la thèse est d'étudier la lumière lente et rapide créée par oscillations cohérentes de population dans les amplificateurs à semi-conducteurs.Nous avons évalué théoriquement et expérimentalement les performances d'une ligne à retards accordables, en termes d'amplitude des retards et déphasages accordables, et de bandes passantes. Nous avons aussi étudié l'impact des oscillations cohérentes de population sur les facteurs de mérite de la liaison opto-électronique. La compréhension des mécanismes physiques mis en jeu nous a amenés à proposer des solutions pour contourner les limites identifiées du composant. Nous avons montré qu'il était possible d'utiliser les lignes à retards accordables au delà de l'inverse du temps de vie des porteurs (500 MHz) en utilisant la montée en fréquence des oscillations cohérentes de population par modulation croisée de gain. Nous avons ainsi obtenu des retards accordables de 389 ps à 16 GHz, sur une bande passante instantanée de 360 MHz. Enfin nous avons proposé une architecture permettant d'obtenir des déphasages accordables proches de 180 degrés à haute fréquence, en substituant l'effet du couplage gain-indice, révélé par l'utilisation d'un filtre optique, par l'excitation paramétrique des oscillations cohérentes de population. Nous avons utilisé ce principe, qui permet par exemple d'atteindre un déphasage accordable de 162 degrés à 2,2 GHz, pour concevoir un oscillateur optoélectronique fonctionnant à 2,2 GHz. La fréquence de ce dernier est rapidement accordable sur 6 MHz à l'aide du courant d'injection de l'amplificateur à semi-conducteur.
318

Méthodologie de résolution des problèmes d'interopérabilité dans le domaine du Product Lifecycle Management

Paviot, Thomas 01 July 2010 (has links) (PDF)
Le travail de recherche présenté dans ce mémoire s'intéresse aux problèmes d'interopérabilité dans le domaine du Product Lifecycle Management (PLM) et vise à proposer une méthodologie capable d'y remédier. Nous définissons l'objectif stratégique du PLM comme la maîtrise de la complexité qui caractérise le développement et le suivi des produits. Dans ce cadre, l'objectif de l'interopérabilité est le contrôle des interactions entre constituants de ce système complexe PLM. Nous montrons que cet objectif est atteint si on assure la continuité et la conservation du flux sémantique qui circule dans le système. Notre étude est restreinte aux seuls domaines de la conception et de la production, mais a l'ambition de pouvoir s'appliquer à d'autres domaines. La continuité du flux sémantique est assurée par une architecture que nous avons baptisée « médiation multi-échelle orientée services ». Le cœur de cette architecture, le médiateur, se charge d'orienter les flux sémantiques vers les systèmes concernés, et met en correspondance sémantique les informations échangées en s'appuyant sur un méta-modèle d'unification. Nous montrons que pour assurer la robustesse, la flexibilité et l'agilité du système ainsi constitué, il faut privilégier le choix d'un méta-modèle standard générique et extensible. A cet effet, nous proposons une cartographie du standard STEP permettant de choisir le méta-modèle pertinent. Nous illustrons le choix et la définition de ce méta-modèle dans le cas de deux problèmes d'interopérabilité des domaines de la conception et de la production : l'interopérabilité CAO/PDM et l'interopérabilité PDM/ERP. Nous expliquons notre démarche dans la mise en œuvre de la norme PLCS. Par ailleurs, nous introduisons un modèle d'annotations sémantiques du produit qui permet de reconstruire des vues multiples correspondant à différents besoins métiers. Un ensemble de démonstrateurs permet de valider nos propositions et nos résultats.
319

Personalised wearable cardiac sensor services for pervasive self-care

Krupaviciute, Asta 20 December 2011 (has links) (PDF)
The aim of the thesis is to design a web services architecture that shall support the automatic determination of a personalised sensor-system, which is embedded in smart garments, and which shall be used in self-care in order to allow a profane user to record himself a personal electrocardiogram (ECG), at anytime and anywhere. The main challenge consists in the intelligent and dynamic orchestration of context-aware business services that supply the user with an optimal personalised solution, while mastering the system's complexity: context dependent user and system interactions, knowledge extraction from subject-specific vital signs, services reconfiguration automation. The solution to this challenge is to create an Ambient Intelligence which goes beyond Ubiquitous Computing and is capable to replace an expert by proposing an Intelligent Assistance to any citizen. We propose a methodology expressed in terms of Data and Model driven Service Oriented Architecture (DM-SOA), which provides a framework for the production of context-aware intelligent business services. This architecture supports the automation of sophisticated and personalised expert activities, which apply professional knowledge to process an individual case. The proposed solution is based on a new dynamic business process modelling approach and in its implementation via automatically reconfigurable services. It consists in setting-up an intelligent environment based on a business process ontology of context-aware concepts and on related context handling rules for services orchestration. A core-ontology has been designed to support the automation of expert activities related to decision-making. The soundness of the method and of the underlying decision-making techniques has been demonstrated in the cardiology domain for selecting the most adequate subject-specific sensor-system, characterised by its ability to yield for an ECG signal of similar diagnostic content than a standard 12-lead ECG. We propose the design of a new three modalities sensor-system prototype as a response to the need of sensor-systems used on demand in self-care situations and ensuring diagnostic quality signals recordings. This prototype has been tested on a set of healthy volunteers presenting various characteristics in age, sex and morphology. In this context, Ambient Intelligence is demonstrated as an ensemble of professional quality services ready to use by profane users. These services are accessible pervasively, trough the objects people work with / wear on / use each day, and provide an appropriate guidance to the non-competent users. Such an Ambient Intelligence approach strongly supports the vision of an Information Society which corresponds to the long-term goal of the EU Information Society Technologies Research Programme that aims to ease knowledge access. The future healthcare will benefit from this approach and will significantly improve patient care.
320

Approche orientée modèles pour la vérification et l'évaluation de performances de l'interopérabilité et l'interaction des services

Ait-Cheik-Bihi, Wafaa, Ait-Cheik-Bihi, Wafaa 21 June 2012 (has links) (PDF)
De nos jours, les services Web sont très utilisés notamment par les entreprises pour rendre accessibles leurs métiers, leurs données et leurs savoir-faire via le Web. L'émergence des services Web a permis aux applications d'être présentées comme un ensemble de services métiers bien structurés et correctement décrits, plutôt que comme un ensemble d'objets et de méthodes. La composition automatique de services est une tâche complexe mais qui rend les services interopérables, ainsi leur interaction permet d'offrir une valeur ajoutée dans le traitement des requêtes des utilisateurs en prenant en compte des critères fonctionnels et non fonctionnels de la qualité de service. Dans ce travail de thèse, nous nous intéressons plus précisément aux services à base de localisation (LBS) qui permettent d'intégrer des informations géographiques, et de fournir des informations accessibles depuis des appareils mobiles via, les réseaux mobiles en faisant usage des positions géographiques de ces appareils. L'objectif de ce travail est de proposer une approche orientée modèles pour spécifier, valider et mettre en œuvre des processus de composition automatique de services à des fins de sécurité routière dans les transports. Cette approche est basée sur deux outils formels à savoir les Réseaux de Petri (RdP) et l'algèbre (max,+). Pour cela, nous préconisons l'utilisation des workflow patterns dans la composition, où chaque pattern est traduit par un modèle RdP et ensuite par une équation mathématique dans l'algèbre (max,+). Les modèles formels développés ont conduits, d'une part, à la description graphique et analytique des processus considérés, et d'autre part, à l'évaluation et la vérification quantitatives et qualitatives de ces processus. Une plateforme, appelée TransportML, pour la collaboration et l'interopérabilité de services à base de positionnement a été implémentée. Les résultats obtenus par la simulation des modèles formels sont comparés à ceux issus des simulations du fonctionnement de la plateforme et des expérimentations sur le terrain.Cette thèse est effectuée dans le cadre des projets Européens FP7 ASSET (2008-2011) et TeleFOT (2008-2012).

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