856 resultados para Parallel and distributed systems
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The InteGrade project is a multi-university effort to build a novel grid computing middleware based on the opportunistic use of resources belonging to user workstations. The InteGrade middleware currently enables the execution of sequential, bag-of-tasks, and parallel applications that follow the BSP or the MPI programming models. This article presents the lessons learned over the last five years of the InteGrade development and describes the solutions achieved concerning the support for robust application execution. The contributions cover the related fields of application scheduling, execution management, and fault tolerance. We present our solutions, describing their implementation principles and evaluation through the analysis of several experimental results. (C) 2010 Elsevier Inc. All rights reserved.
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This paper presents a configurable architecture which was designed to aid in the simulation of ULSI circuits at the transistor level. Elsewhere [1] this architecture was shown to be able to run such simulations several times as fast as standard circuit simulators such as SPICES. In this paper, after describing the overall idea and the the architecture of the system as a whole, I concentrate on the description of the architecture of the processing elements of the computing array.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This thesis offers a practical and theoretical evaluations about gossip-epidemic algorithms, comparing those most common in the literature with new proposed algorithms and analyzing their behavior. Tests have been executed using one hundred graphs that has been randomly generated by Large Unstructured NEtwork Simulator (LUNES), a simulation software provided by Parallel and Distributed Simulation Research Group (PADS), of the Department of Computer Science, Università di Bologna and simulated using Advanced RTI System (ARTÌS), based on the High Level Architecture standard. Literatures algorithms have been analyzed and taken as base for new algorithms.
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Wireless Multimedia Sensor Networks (WMSNs) promise a wide scope of emerging potential applications in both civilian and military areas, which require visual and audio information to enhance the level of collected information. The transmission of multimedia content requires a minimal video quality level from the user’s perspective. However, links in WMSN communi- cations are typically unreliable, as they often experience fluctuations in quality and weak connectivity, and thus, the routing protocol must evaluate the routes by using end-to-end link quality information to increase the packet delivery ratio. Moreover, the use multiple paths together with key video metrics can enhance the video quality level. In this paper, we propose a video-aware multiple path hierarchical routing protocol for efficient multimedia transmission over WMSN, called video-aware MMtransmission. This protocol finds node-disjoint multiple paths, and implements an end-to-end link quality estimation with minimal over- head to score the paths. Thus, our protocol assures multimedia transmission with Quality of Experience (QoE) and energy-efficiency support. The simula- tion results show the benefits of video-aware MMtransmission for disseminating video content by means of energy-efficiency and QoE analysis.
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Membrane systems are parallel and bioinspired systems which simulate membranes behavior when processing information. As a part of unconventional computing, P-systems are proven to be effective in solvingcomplexproblems. A software technique is presented here that obtain good results when dealing with such problems. The rules application phase is studied and updated accordingly to obtain the desired results. Certain rules are candidate to be eliminated which can make the model improving in terms of time.
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The 4CaaSt project aims at developing a PaaS framework that enables flexible definition, marketing, deployment and management of Cloud-based services and applications. The major innovations proposed by 4CaaSt are the blueprint and its management and lifecycle, a one stop shop for Cloud services and the management of resources in the PaaS level (including elasticity). 4CaaSt also provides a portfolio of ready to use Cloud native services and Cloud- aware immigrant technologies.
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The dHDL language has been defined to improve hardware design productivity. This is achieved through the definition of a better reuse interface (including parameters, attributes and macroports) and the creation of control structures that help the designer in the hardware generation process.
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In this paper, an architecture based on a scalable and flexible set of Evolvable Processing arrays is presented. FPGA-native Dynamic Partial Reconfiguration (DPR) is used for evolution, which is done intrinsically, letting the system to adapt autonomously to variable run-time conditions, including the presence of transient and permanent faults. The architecture supports different modes of operation, namely: independent, parallel, cascaded or bypass mode. These modes of operation can be used during evolution time or during normal operation. The evolvability of the architecture is combined with fault-tolerance techniques, to enhance the platform with self-healing features, making it suitable for applications which require both high adaptability and reliability. Experimental results show that such a system may benefit from accelerated evolution times, increased performance and improved dependability, mainly by increasing fault tolerance for transient and permanent faults, as well as providing some fault identification possibilities. The evolvable HW array shown is tailored for window-based image processing applications.
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Las Redes de Procesadores Evolutivos-NEP propuestas en [Mitrana et al., 2001], son un modelo computacional bio-inspirado a partir de la evolución de poblaciones de células, definiendo a nivel sintáctico algunas propiedades biológicas. En este modelo, las células están representadas por medio de palabras que describen secuencias de ADN. Informalmente, en algún instante de tiempo, el sistema evolutivo está representado por una colección de palabras cada una de las cuales representa una célula. El espacio genotipo de las especies, es un conjunto que recoge aquellas palabras que son aceptadas como sobrevivientes (es decir, como \correctas"). Desde el punto de vista de la evolución, las células pertenecen a especies y su comunidad evoluciona de acuerdo a procesos biológicos como la mutación y la división celular. éstos procesos representan el proceso natural de evolución y ponen de manifiesto una característica intrínseca de la naturaleza: el paralelismo. En este modelo, estos procesos son vistos como operaciones sobre palabras. Formalmente, el modelo de las NEP constituyen una arquitectura paralela y distribuida de procesamiento simbólico inspirada en la Máquina de conexión [Hillis, 1981], en el Paradigma de Flujo Lógico [Errico and Jesshope, 1994] y en las Redes de Procesadores Paralelos de Lenguajes (RPPL) [Csuhaj-Varju and Salomaa, 1997]. Al modelo NEP se han ido agregando nuevas y novedosas extensiones hasta el punto que actualmente podemos hablar de una familia de Redes de Procesadores Bio-inspirados (NBP) [Mitrana et al., 2012b]. Un considerable número de trabajos a lo largo de los últimos años han demostrado la potencia computacional de la familia NBP. En general, éstos modelos son computacionalmente completos, universales y eficientes [Manea et al., 2007], [Manea et al., 2010b], [Mitrana and Martín-Vide, 2005]. De acuerdo a lo anterior, se puede afirmar que el modelo NEP ha adquirido hasta el momento un nivel de madurez considerable. Sin embargo, aunque el modelo es de inspiración biológica, sus metas siguen estando motivadas en la Teoría de Lenguajes Formales y las Ciencias de la Computación. En este sentido, los aspectos biológicos han sido abordados desde una perspectiva cualitativa y el acercamiento a la realidad biológica es de forma meramente sintáctica. Para considerar estos aspectos y lograr dicho acercamiento es necesario que el modelo NEP tenga una perspectiva más amplia que incorpore la interacción de aspectos tanto cualitativos como cuantitativos. La contribución de esta Tesis puede considerarse como un paso hacia adelante en una nueva etapa de los NEPs, donde el carácter cuantitativo del modelo es de primordial interés y donde existen posibilidades de un cambio visible en el enfoque de interés del dominio de los problemas a considerar: de las ciencias de la computación hacia la simulación/modelado biológico y viceversa, entre otros. El marco computacional que proponemos en esta Tesis extiende el modelo de las Redes de Procesadores Evolutivos (NEP) y define arquitectura inspirada en la definición de bloques funcionales del proceso de señalización celular para la solución de problemas computacionales complejos y el modelado de fenómenos celulares desde una perspectiva discreta. En particular, se proponen dos extensiones: (1) los Transductores basados en Redes de Procesadores Evolutivos (NEPT), y (2) las Redes Parametrizadas de Procesadores Evolutivos Polarizados (PNPEP). La conservación de las propiedades y el poder computacional tanto de NEPT como de PNPEP se demuestra formalmente. Varias simulaciones de procesos relacionados con la señalización celular son abordadas sintáctica y computacionalmente, con el _n de mostrar la aplicabilidad e idoneidad de estas dos extensiones. ABSTRACT Network of Evolutionary Processors -NEP was proposed in [Mitrana et al., 2001], as a computational model inspired by the evolution of cell populations, which might model some properties of evolving cell communities at the syntactical level. In this model, cells are represented by words which encode their DNA sequences. Informally, at any moment of time, the evolutionary system is described by a collection of words, where each word represents one cell. Cells belong to species and their community evolves according to mutations and division which are defined by operations on words. Only those cells accepted as survivors (correct) are represented by a word in a given set of words, called the genotype space of the species. This feature is analogous with the natural process of evolution. Formally, NEP is based on an architecture for parallel and distributed processing inspired from the Connection Machine [Hillis, 1981], the Flow Logic Paradigm [Errico and Jesshope, 1994] and the Networks of Parallel Language Processors (RPPL) [Csuhaj-Varju and Salomaa, 1997]. Since the date when NEP was proposed, several extensions and variants have appeared engendering a new set of models named Networks of Bio-inspired Processors (NBP) [Mitrana et al., 2012b]. During this time, several works have proved the computational power of NBP. Specifically, their efficiency, universality, and computational completeness have been thoroughly investigated [Manea et al., 2007, Manea et al., 2010b, Mitrana and Martín-Vide, 2005]. Therefore, we can say that the NEP model has reached its maturity. Nevertheless, although the NEP model is biologically inspired, this model is mainly motivated by mathematical and computer science goals. In this context, the biological aspects are only considered from a qualitative and syntactical perspective. In view of this lack, it is important to try to keep the NEP theory as close as possible to the biological reality, extending their perspective incorporating the interplay of qualitative and quantitative aspects. The contribution of this Thesis, can be considered as a starting point in a new era of the NEP model. Then, the quantitative character of the NEP model is mandatory and it can address completely new different types of problems with respect to the classical computational domain (e.g. from the computer science to system biology). Therefore, the computational framework that we propose extends the NEP model and defines an architecture inspired by the functional blocks from cellular signaling in order to solve complex computational problems and cellular phenomena modeled from a discrete perspective. Particularly, we propose two extensions, namely: (1) Transducers based on Network of Evolutionary Processors (NEPT), and (2) Parametrized Network of Polarized Evolutionary Processors (PNPEP). Additionally, we have formally proved that the properties and computational power of NEP is kept in both extensions. Several simulations about processes related with cellular signaling both syntactical and computationally have been considered to show the model suitability.
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Debido a la creciente relevancia de la computación en la nube y de los sistemas distribuidos, cobran también creciente interés las herramientas que ayudan a los desarrolladores y administradores a desempeñar sus funciones con la mayor eficacia posible. Por ello el objetivo principal de este trabajo es el desarrollo de una herramienta capaz de crear y controlar un entorno de almacenamiento de claves distribuidas desde una máquina local e independiente, aumentando la productividad mediante la automatización de todas las tareas. La herramienta desarrollada tiene la capacidad necesaria para integrarse tanto en proyectos que se encuentren en marcha como para proyectos que aún no hayan comenzado y proveer una solución sencilla, eficaz, y, sobre todo, útil. A lo largo del trabajo se ha realizado una gran tarea de análisis para determinar cuáles serán, de entre las posibilidades existentes, las más apropiadas para su implementación, teniendo en cuenta las tecnologías líderes disponibles en el estado del arte. Ello ha requerido también la obtención de una mejor comprensión de su funcionamiento interno. Se han realizado diferentes diseños que se han analizado y discutido en detalle para encontrar la solución que mejor se adaptaba a los objetivos propuestos. Y finalmente se ha desarrollado una herramienta ligera y sencilla, pero con un gran potencial para la administración. ---ABSTRACT---Due to the growing relevance of cloud computing and distributed systems it seems interesting to take into account the importance of the administration tools that help developers and administrators fulfill their duties in the most efficient ways. Because of this motivation, the main objective of this project is the development of a tool capable of creating and controlling a distributed key storing environment from a local and independent machine, improving the productivity thanks to the automation of all the involved tasks. The developed tool is able to integrate itself into already running projects as well as in not-yet-started ones, providing a simple, efficient and overall useful solution. During this project big tasks of research and analysis have taken place in order to determine, from the existent possibilities, the most suitable for its implementation, taking into account the leading technologies in the sector, which are described in the state of the art section. This has required the acquisition of a better insight of their inner workings. Some different designs have been made and have been discussed in detail with the intention of finding the solution that best suits the proposed objectives. And finally a lightweight and simple tool has been developed, which presents a very big potential for administration tasks.
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La creciente complejidad, heterogeneidad y dinamismo inherente a las redes de telecomunicaciones, los sistemas distribuidos y los servicios avanzados de información y comunicación emergentes, así como el incremento de su criticidad e importancia estratégica, requieren la adopción de tecnologías cada vez más sofisticadas para su gestión, su coordinación y su integración por parte de los operadores de red, los proveedores de servicio y las empresas, como usuarios finales de los mismos, con el fin de garantizar niveles adecuados de funcionalidad, rendimiento y fiabilidad. Las estrategias de gestión adoptadas tradicionalmente adolecen de seguir modelos excesivamente estáticos y centralizados, con un elevado componente de supervisión y difícilmente escalables. La acuciante necesidad por flexibilizar esta gestión y hacerla a la vez más escalable y robusta, ha provocado en los últimos años un considerable interés por desarrollar nuevos paradigmas basados en modelos jerárquicos y distribuidos, como evolución natural de los primeros modelos jerárquicos débilmente distribuidos que sucedieron al paradigma centralizado. Se crean así nuevos modelos como son los basados en Gestión por Delegación, en el paradigma de código móvil, en las tecnologías de objetos distribuidos y en los servicios web. Estas alternativas se han mostrado enormemente robustas, flexibles y escalables frente a las estrategias tradicionales de gestión, pero continúan sin resolver aún muchos problemas. Las líneas actuales de investigación parten del hecho de que muchos problemas de robustez, escalabilidad y flexibilidad continúan sin ser resueltos por el paradigma jerárquico-distribuido, y abogan por la migración hacia un paradigma cooperativo fuertemente distribuido. Estas líneas tienen su germen en la Inteligencia Artificial Distribuida (DAI) y, más concretamente, en el paradigma de agentes autónomos y en los Sistemas Multi-agente (MAS). Todas ellas se perfilan en torno a un conjunto de objetivos que pueden resumirse en alcanzar un mayor grado de autonomía en la funcionalidad de la gestión y una mayor capacidad de autoconfiguración que resuelva los problemas de escalabilidad y la necesidad de supervisión presentes en los sistemas actuales, evolucionar hacia técnicas de control fuertemente distribuido y cooperativo guiado por la meta y dotar de una mayor riqueza semántica a los modelos de información. Cada vez más investigadores están empezando a utilizar agentes para la gestión de redes y sistemas distribuidos. Sin embargo, los límites establecidos en sus trabajos entre agentes móviles (que siguen el paradigma de código móvil) y agentes autónomos (que realmente siguen el paradigma cooperativo) resultan difusos. Muchos de estos trabajos se centran en la utilización de agentes móviles, lo cual, al igual que ocurría con las técnicas de código móvil comentadas anteriormente, les permite dotar de un mayor componente dinámico al concepto tradicional de Gestión por Delegación. Con ello se consigue flexibilizar la gestión, distribuir la lógica de gestión cerca de los datos y distribuir el control. Sin embargo se permanece en el paradigma jerárquico distribuido. Si bien continúa sin definirse aún una arquitectura de gestión fiel al paradigma cooperativo fuertemente distribuido, estas líneas de investigación han puesto de manifiesto serios problemas de adecuación en los modelos de información, comunicación y organizativo de las arquitecturas de gestión existentes. En este contexto, la tesis presenta un modelo de arquitectura para gestión holónica de sistemas y servicios distribuidos mediante sociedades de agentes autónomos, cuyos objetivos fundamentales son el incremento del grado de automatización asociado a las tareas de gestión, el aumento de la escalabilidad de las soluciones de gestión, soporte para delegación tanto por dominios como por macro-tareas, y un alto grado de interoperabilidad en entornos abiertos. A partir de estos objetivos se ha desarrollado un modelo de información formal de tipo semántico, basado en lógica descriptiva que permite un mayor grado de automatización en la gestión en base a la utilización de agentes autónomos racionales, capaces de razonar, inferir e integrar de forma dinámica conocimiento y servicios conceptualizados mediante el modelo CIM y formalizados a nivel semántico mediante lógica descriptiva. El modelo de información incluye además un “mapping” a nivel de meta-modelo de CIM al lenguaje de especificación de ontologías OWL, que supone un significativo avance en el área de la representación y el intercambio basado en XML de modelos y meta-información. A nivel de interacción, el modelo aporta un lenguaje de especificación formal de conversaciones entre agentes basado en la teoría de actos ilocucionales y aporta una semántica operacional para dicho lenguaje que facilita la labor de verificación de propiedades formales asociadas al protocolo de interacción. Se ha desarrollado también un modelo de organización holónico y orientado a roles cuyas principales características están alineadas con las demandadas por los servicios distribuidos emergentes e incluyen la ausencia de control central, capacidades de reestructuración dinámica, capacidades de cooperación, y facilidades de adaptación a diferentes culturas organizativas. El modelo incluye un submodelo normativo adecuado al carácter autónomo de los holones de gestión y basado en las lógicas modales deontológica y de acción.---ABSTRACT---The growing complexity, heterogeneity and dynamism inherent in telecommunications networks, distributed systems and the emerging advanced information and communication services, as well as their increased criticality and strategic importance, calls for the adoption of increasingly more sophisticated technologies for their management, coordination and integration by network operators, service providers and end-user companies to assure adequate levels of functionality, performance and reliability. The management strategies adopted traditionally follow models that are too static and centralised, have a high supervision component and are difficult to scale. The pressing need to flexibilise management and, at the same time, make it more scalable and robust recently led to a lot of interest in developing new paradigms based on hierarchical and distributed models, as a natural evolution from the first weakly distributed hierarchical models that succeeded the centralised paradigm. Thus new models based on management by delegation, the mobile code paradigm, distributed objects and web services came into being. These alternatives have turned out to be enormously robust, flexible and scalable as compared with the traditional management strategies. However, many problems still remain to be solved. Current research lines assume that the distributed hierarchical paradigm has as yet failed to solve many of the problems related to robustness, scalability and flexibility and advocate migration towards a strongly distributed cooperative paradigm. These lines of research were spawned by Distributed Artificial Intelligence (DAI) and, specifically, the autonomous agent paradigm and Multi-Agent Systems (MAS). They all revolve around a series of objectives, which can be summarised as achieving greater management functionality autonomy and a greater self-configuration capability, which solves the problems of scalability and the need for supervision that plague current systems, evolving towards strongly distributed and goal-driven cooperative control techniques and semantically enhancing information models. More and more researchers are starting to use agents for network and distributed systems management. However, the boundaries established in their work between mobile agents (that follow the mobile code paradigm) and autonomous agents (that really follow the cooperative paradigm) are fuzzy. Many of these approximations focus on the use of mobile agents, which, as was the case with the above-mentioned mobile code techniques, means that they can inject more dynamism into the traditional concept of management by delegation. Accordingly, they are able to flexibilise management, distribute management logic about data and distribute control. However, they remain within the distributed hierarchical paradigm. While a management architecture faithful to the strongly distributed cooperative paradigm has yet to be defined, these lines of research have revealed that the information, communication and organisation models of existing management architectures are far from adequate. In this context, this dissertation presents an architectural model for the holonic management of distributed systems and services through autonomous agent societies. The main objectives of this model are to raise the level of management task automation, increase the scalability of management solutions, provide support for delegation by both domains and macro-tasks and achieve a high level of interoperability in open environments. Bearing in mind these objectives, a descriptive logic-based formal semantic information model has been developed, which increases management automation by using rational autonomous agents capable of reasoning, inferring and dynamically integrating knowledge and services conceptualised by means of the CIM model and formalised at the semantic level by means of descriptive logic. The information model also includes a mapping, at the CIM metamodel level, to the OWL ontology specification language, which amounts to a significant advance in the field of XML-based model and metainformation representation and exchange. At the interaction level, the model introduces a formal specification language (ACSL) of conversations between agents based on speech act theory and contributes an operational semantics for this language that eases the task of verifying formal properties associated with the interaction protocol. A role-oriented holonic organisational model has also been developed, whose main features meet the requirements demanded by emerging distributed services, including no centralised control, dynamic restructuring capabilities, cooperative skills and facilities for adaptation to different organisational cultures. The model includes a normative submodel adapted to management holon autonomy and based on the deontic and action modal logics.