Recursos de colección

RiuNet. Repositorio institucional de la Universitat de Valencia (99.709 recursos)

RiuNet es el Repositorio Institucional de la Universitat Politècnica de València, gestionado por la Biblioteca, cuyo objetivo es ofrecer acceso en Internet a la producción científica, académica y corporativa de la comunidad universitaria con la finalidad de aumentar su visibilidad y hacerla accesible y preservable.

Congresos. Editorial UPV

Mostrando recursos 1 - 20 de 1.231

  1. Web of Energy: hacia la integración inteligente para las redes de sensores en Smart Grids

    Caballero, Victor; Vernet, David; Zaballos, Agustín; Corral, Guiomar
    [ES] Las Smart Grids se presentan como una solución a la demanda de la gestión distribuida e inteligente de la energía, mejorando así las funciones de automatización, recolección y procesamiento de datos. Para dar soporte a estas funciones inteligentes, es necesario el despliegue de novedosas infraestructuras TIC diseñadas para tal propósito. Una de las principales problemáticas de las Smart Grids es la heterogeneidad de protocolos de comunicación utilizados por los dispositivos inteligentes que las integran. Para dar solución a este problema, se propone el uso del concepto de la Web of Things. Sin embargo, somos conscientes de que las entidades...

  2. Diseño y evaluación de un servicio OpenFlow de provisión de Calidad de Experiencia sobre Mininet

    Prieto Sánchez, Cristian; Andrés Maldonado, Pilar; Prados Garzón, Jonathan; Ramos-Munoz, Juan J.
    [ES] Las redes definidas por software suponen unnuevo paradigma de red que potencialmente pueden pro-porcionar nuevas soluciones para proporcionar calidad deexperiencia.En este trabajo se propone un diseño de aplicación deredes definidas por software para proveer calidad de experi-encia a flujos con distintos requisitos de red. Esta aplicaciónse implementa en OpenDayLight, una implementación dereferencia, y se ejecuta en el emulador Mininet.En este artı́culo se detallan los algoritmos implementadospara proporcionar la aplicación para OpenDayLight.

  3. Plataforma extremo-a-extremo compatible con el estándar HbbTV 2.0 para la TV híbrida y multi-dispositivo

    Marfil, Daniel; Boronat, Fernando; Montagud, Mario; Salvador Llàcer, Pau
    [ES] En este artículo se presenta una plataforma extremo-a-extremo para la generación, entrega y sincronización de contenidos híbridos (broadcast y broadband) relacionados, tanto en un mismo como en múltiples dispositivos (ej. escenario multi-pantalla). La plataforma es compatible con la versión más reciente del estándar Hybrid Broadcast Broadband TV (2.0.1) y, además, incluye soluciones eficientes para aspectos clave que no están especificados en dicho estándar, pero que son necesarios para la implantación satisfactoria de servicios de TV híbridos y multi-dispositivo, como: mecanismos de señalización para descubrir, asociar y describir los contenidos (híbridos) adicionales relacionados, mecanismos de interacción y negociación entre los...

  4. Simulación genérica a nivel de sistema para soluciones avanzadas de gestión de recursos

    Rodríguez, Paula; Sarasúa, Paula; Diez, Luis; Agüero, Ramón
    [ES] A pesar del notable esfuerzo llevado a cabo porla comunidad científica en el ámbito de la tecnología LTE,aún no existe una metodología globalmente aceptada paraanalizar este tipo de redes. Igualmente, no se conoce unaúnica solución que responda a todos los requisitos que sepueden plantear a la hora de acometer su análisis, de modoque se emplean diferentes herramientas y soluciones, cadauna con sus ventajas e inconvenientes. Una de las limitacionesmás importantes es la dificultad para evaluar escenarios conun número elevado de elementos de red, lo que podría reflejarla situación de redes heterogéneas (HetNets). En otros casos,no se presta mucha atención...

  5. Implementación de mecanismos de mitigación de tormentas de broadcast en redes de área local mediante Redes Definidas por Software

    Valera Muros, Bárbara; Prados Garzón, Jonathan; Ramos-Munoz, Juan J.; Navarro-Ortiz, Jorge
    [ES] El uso de Ethernet como tecnologı́a de red pararedes corporativas se justifica por su bajo coste y facilidadde configuración y mantenimiento. Sin embargo, estas redesno son muy escalables, debido en parte a las inundacioneso tormentas de broadcasts, que afectan al rendimiento tantode los dispositivos de red como finales. Para mitigar elimpacto de las inundaciones por broadcast, se ha previstoutilizar técnicas de filtrado y caché en distintos nodos dela red. Sin embargo, el paradigma de Redes Definidas porSoftware permite definir nuevas aproximaciones, gracias ala capacidad de reprogramar la red de forma centralizaday flexible que proporciona. En este trabajo se aborda...

  6. Multivariate statistical technique over QoS variables to analyze video quality metrics on IEEE 802.11ac networks

    García-Pineda, Miguel; Felici-Castell, Santiago; Segura-Garcia, Jaume
    [EN] We present the results from a measurementbasedperformance evaluation of wireless networks basedon IEEE 802.11ac standard in an indoor environment, withthe aim to analyze their performance under high definitionstreaming video applications. We focus our study on analyzingthe highest performance of these standards using off-theshelfequipment as well as the behavior of Quality of Servicevariables and how they affect to the video quality. Thus, wehave analyzed and measured these variables and have applieda multivariate statistical technique, called Factor Analysis,and finally discuss their behavior.

  7. Aplicación Web para comunicación multimedia en tiempo real y en movilidad

    Gil Alvárez, Miguel; Macías López, Elsa; Suárez Sarmiento, Alvaro
    [ES] En este documento se presenta una aplicación Web para comunicación multimedia en tiempo real y compatible con dispositivos móviles, combinando varias tecnologías que son tendencia actualmente en el mundo del desarrollo: HTML5, WebRTC y Node.js. A partir de las tecnologías anteriores se ha desarrollado una plataforma que desde un navegador compatible permite: realizar videoconferencias en grupo, enviar y recibir archivos, conversaciones en texto privadas entre usuarios, conversaciones de texto en grupo y grabación de las emisiones multimedia de cualquiera de los usuarios de la sala. A nivel visual, se ha diseñado una interfaz simple de usar y completamente responsiva,...

  8. Servicio centralizado de proyección de material docente

    Navarro Ortiz, Jorge; Sendra, Sandra; Ameigeiras, Pablo; Torre, Angel de la; Garcia, Luz; Gomez, Angel; Lopez-Soler, Juan; Mota, Sonia; Padilla, Pablo; Prados-Garzon, Jonathan; Ramirez, Javier; Ramos-Munoz, Juan; Ruiz-Moya, Antonio; Segura, Jose
    [ES] En los últimos años las tecnologías TIC se han ido incorporando en los diferentes ámbitos de la enseñanza, desde las pizarras electrónicas para las clases magistrales hasta el uso de tabletas para la visualización de libros docentes en formato electrónico. De hecho, resulta cada vez más frecuente que los docentes empleen sus portátiles para presentar su material en formato de transparencias. No obstante, esto implica que los profesores deben llevar sus portátiles al aula y conectarlos a través de un cable, sea VGA o HDMI, al proyector. Esto resta movilidad al profesor, anclado a través del cable al proyector,...

  9. Estudio longitudinal de las calificaciones de evaluación continua en la asignatura de Arquitectura de Redes II del Grado en Ingeniería de Tecnologías y Servicios de Telecomunicación

    López de Vergara, Jorge; Olmos, Ricardo
    [ES] En este artículo se realiza un estudio longitudinal de las calificaciones de evaluación continua de la asignatura Arquitectura de Redes II, del Grado en Ingeniería de Tecnologías y Servicios de Telecomunicación que se oferta en la Universidad Autónoma de Madrid. Para ello se analizan las calificaciones obtenidas en los veinte controles realizados durante cinco cursos académicos. Los resultados muestran que, en general, existe una alta correlación en las calificaciones que obtienen los estudiantes entre las distintas pruebas de cada curso, lo cual permite corroborar que los ejercicios han sido correctamente planteados. Igualmente, se comparan los resultados obtenidos entre cursos...

  10. Evaluating the Impact of Energy-Aware Routing on Software-Defined Networking Performance

    Fernández-Fernández, Adriana; Cervelló-Pastor, Cristina; Ochoa-Aday, Leonardo
    [EN] Increasing power consumption and CO2 emissions generated by large data networks have become a major concern over the last decade. For this problem, the emerging paradigm of Software-Defined Networks (SDN) can be seen as an attractive solution. In these networks an energy-aware routing model could be easily implemented leveraging the control and data plane separation. This paper investigates the impact of energy-aware routing on SDN performance. To that end, we propose a novel energy- aware mechanism that reduces the number of active links in SDN with multiple controllers, considering in-band control traffic, i.e. links are shared between data and...

  11. Binary cavitation in a transparent three hole GDI nozzle

    Chaves, Humberto; Donath, Sebastian
    [EN] A more or less real size three hole (0.1 mm diameter) transparent injection nozzle was made with 120° between the orifices and an inclination of 20° to the injector axis. The geometry is similar to that of a multi hole GDI injector. Experiments are performed using n-pentane and -methyl-naphtalene mixtures in varying composition. The flow in the orifices is observed under submerged injection conditions from downstream looking in direction of the injector using a beam splitter plate for illumination with the light from a Minilite NdYag laser that was made incoherent by fluorescence in a cuvette filled with a dilute rhodamine-ethanol mixture. The images...

  12. Spreading model for wall films generated by high-pressure sprays

    Lamiel, Quentin; Lamarque, Nicolas; Hélie, Jérome; Legendre, Dominique
    [EN] This paper presents a new model developed to predict the area of wall films that may develop in gasoline direct injection engines (GDI). In a always more restrictive legislation on gas emissions the injection process in internal combustion (IC) engines has been highlighted as a domain of great concern in order to satisfy these requirements. Many spray wall interactions models exist in literature and are included in different CFD tools. Most often they are based on the sum of single drop-wall impacts. The specificity of the present model lies in its simplicity and the way the film is treated globally. Here its propagation is...

  13. Fuel spray vapour distribution correlations for a high pressure diesel fuel spray cases for different injector nozzle geometries.

    Njere, Darlington; Emekwuru, Nwabueze
    [EN] The evolution of diesel fuel injection technology, to facilitate strong correlations of in-cylinder spray propagation with injection conditions and injector geometry, is crucial in facing emission challenges. More observations of spray propagation are, therefore, required to provide valuable information on how to ensure that all the injected fuel has maximum contact with the available air, to promote complete combustion and reduce emissions. In this study, high pressure diesel fuel sprays are injected into a constant-volume chamber at injection and ambient pressure values typical of current diesel engines. For these types of sprays the maximum fuel liquid phase penetration is different and reached sooner than the...

  14. A study of the controlling parameters of fuel air mixture formation for ECN Spray A

    Vogiatzaki, Konstantina; Crua, Cyril; Morgan, Robert; Heikal, Morgan
    [EN] Designing future ultra-high efficiency, ultra-low emission engines requires an in depth understanding of the multiscale, multi-phase phenomena taking place in the combustion chamber. The performance of the fuel delivery system is key in the air fuel mixture formation and hence the combustion characteristics, however in most spray modelling approaches is not considered directly. Thus, it is important to understand how the selection of models that mimic injection process affect predictions. In this paper we present an Eulerian-Lagrangian framework based on OpenFOAM libraries to model spray injection dynamics. The framework accounts for primary droplet formation (based on a parcel method with predefined initial droplet size distribution),...

  15. Viability of coaxial atomization for disintegration of cell solutions in cell spray applications

    Bieber, Malte; Menzel, Sarah; Thiebes, Anja; Cornelissen, Christian; Jockenhoevel, Stefan; Kneer, Reinhold; Reddemann, Manuel
    [EN] Treating Leukemia with intravenous stem cell transplantation represents a well-established therapy technique. For applications, that require high local cell concentrations, transplantation by conventional intravenous injection is less potent, due to cell distribution with blood circulation. Instead, spraying them directly onto the injured or diseased area shows promising results in various applications, e.g. superficial treatment of topographically challenging wounds, in situ seeding of cells on implants, deposition of cells in tubular organs for stem cell therapy. The present work aims for a basic knowledge about viability boundaries for coaxial cell-spray atomization and the reciprocal influence between cells in solution and primary breakup mechanics. A generic modular...

  16. Direct numerical simulation of an atomizing biodiesel jet: Impact of fuel properties on atomization characteristics

    Ling, Yue; Legros, Guillaume; Popinet, Stéphane; Zaleski, Stéphane
    [EN] The utilization of biodiesel is an effective approach to reduce pollution from internal combustion engines and thus has attracted steadily increasing interest in the recent years. As the viscosity of biodiesel is much higher than that of standard diesel, the atomization characteristics of a biodiesel jet can significantly deviate from those of a standard diesel jet under identical injection conditions. Since atomization of the injected fuel has a strong impact on fuel-air mixing and the following combustion processes, it is important to investigate the atomization of biodiesel and in particular to understand how the fuel properties affect the atomization process and the resulting spray...

  17. Models for automotive fuel droplets heating and evaporation

    al Qubeissi, Mansour; Sazhin, Sergei; Al-Esawi, Nawar
    [EN] The paper presents recent approaches to the modelling of heating and evaporation of automotive fuel droplets with application to biodiesel, diesel, gasoline, and blended fuels in conditions representative of internal combustion engines. The evolutions of droplet radii and temperatures for gasoline, diesel, and a broad range of biodiesel fuels and their selective diesel fuel blends have been predicted using the Discrete Component model (DCM). These mixtures combine up to 112 components of hydrocarbons and methyl esters. The results are compared with the predictions of the case when blended diesel-biodiesel fuel are represented by pure fossil and biodiesel fuels. In contrast to previous studies, it is...

  18. Statistical methods of images analysis as an essential tool in the assessment process of computer methods intended for numerical simulations of cavitating flows

    Niedźwiedzka, Agnieszka; Lipiński, Seweryn
    [EN] Cavitation, because of its negative effects, like e.g. erosion, noise or vibration, is usually an undesirable phenomenon. However, in devices where spraying and atomization are expected, cavitation is required. This group of devices includes e.g. diesel injectors. Appearance of vapour bubbles results in increase of the maximum flow velocity. It is possible for the following reasons. Firstly, bubbles start to form in the throat, so its diameter reduces. Secondly, appearance of vapour bubbles along the wall results in a slip boundary condition. Moreover, cavitation has a positive influence on a spray cone angle. However, regardless of the place of occurrence, research on cavitation bases primarily...

  19. Simulation of droplet spreading on micro-CT reconstructed 3D real porous media using the volume-of-fluid method

    Aboukhedr, Mahmoud; Mitroglou, Nicholas; Georgoulas, Anastasios; Marengo, Marco; Vogiatzaki, Konstantina
    [EN] Droplet impact on porous media has a broad range of applications such as material processing, drug delivery and ink injection etc. The simulation studies of such processes are rather limited. To represent the spreading and absorption process of the droplet on porous materials, robust numerical schemes capable of accurately representing wettability as well as capillary effects need to be established. The current work, presents one of the first studies of droplet impact on a real porous media geometry model extracted from a micro-CT scan. The process involves processing of CT image and subsequent threshold based on the structures segmentation. The porous geometry is extracted in...

  20. Influence of the chemical mechanism in the frame of diesel-like CFD reacting spray simulations using a presumed PDF flamelet-based combustion model

    Payri González, Francisco; García Oliver, José María; Novella Rosa, Ricardo; Pérez Sánchez, Eduardo Javier
    [EN] The ability of a computational fluid dynamics (CFD) simulation to reproduce the diesel-like reacting spray ignition process and its corresponding flame structure strongly depends on both the fidelity of the chemical mechanism for reproducing the oxidation of the fuel and also on how the turbulence-chemistry interaction (TCI) is modeled. Therefore, investigating the performance of different chemical mechanisms not only in perfect stirred reactors but directly in the diesel-like spray itself is of great interest in order to evaluate their suitability for being further applied to CFD engine simulations. This research work focuses on applying a presumed probability density function (PDF) unsteady flamelet combustion model to the...

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