Дисертації з теми "Dynamics, Distributed Computing"
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Weed, Richard Allen. "Computational strategies for three-dimensional flow simulations on distributed computing systems." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/12154.
Повний текст джерелаRIZZO, SARA. "Simple Dynamics as Algorithms and Models." Doctoral thesis, Gran Sasso Science Institute, 2021. http://hdl.handle.net/20.500.12571/21452.
Повний текст джерелаBangalore, Ashok K. "Computational fluid dynamic studies of high lift rotor systems using distributed computing." Diss., Georgia Institute of Technology, 1995. http://hdl.handle.net/1853/12949.
Повний текст джерелаLiu, Xing. "High-performance algorithms and software for large-scale molecular simulation." Diss., Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53487.
Повний текст джерелаWard, Koeck Alan. "Modeling and distributed computing of snow transport and delivery on meso-scale in a complex orography." Doctoral thesis, Universitat Oberta de Catalunya, 2015. http://hdl.handle.net/10803/327598.
Повний текст джерелаEl estudio describe los principios de funcionamiento ya validación de un modelo para ordenador de dinámica de fluidos computacional del proceso de caída de nieve sobre una orografía compleja. Se discretea el dominio espacial con énfasis principal sobre una topografía dificultosa que tiende a producir volúmenes deformes en la cuadrícula de cálculo. Se define una nueva mesura de la deformación de los elementos de la cuadrícula, y se aplica en la discusión de diferentes estrategias de optimización de la cuadrícula para reducir el coste del cálculo paralelo por ordenador de soluciones de las ecuaciones de transporte de fluidos de Navier-Stokes. Se diseña un modelo por ordenador que resuelve las ecuaciones Navier-Stokes para un fluido incomprensible y turbulento. Se discute la eficiencia de la caja de herramientas CFD. Se trabaja el grado de conexión necesario entre las dos fases de nieve y de aire del fluido durante la modelización de la caída de nieve por ordenador. Se implementa una metodología Euler-Lagrangian de dos fluidos. Se presentan aplicaciones de caída de nieve en relación con la planificación de pistas de esquí, sacar la nieve de carreteras de alta momntaña, y la planificación de la producción de energía eólica.
This study describes the working principles and validation of a Computational Fluid Dynamics computer model of snowfall over a complex orography, for optimizing ski slope or other installations according to local weather patterns. The spatial domain is discretized, focusing on challenging topography that tends to produce deformed mesh volumes. A novel measure od mesh deformation is defined and applied to discuss different strategies of mesh optimization with the goal of facilitating parallel computer solutions of the Navier-Stokes fluid transport equations. A computer model is designed to solve the Navier-Stokes incompressible turbulent fluid equations. The efficiency of the CFD computational toolkit is discussed. The degree od coupling required between the snow – and air-phases of the fluid during the computer modeling of snowfall is discussed. A two-fluid (Euler-Lagrangian) methodology is implemented. Applications of such snowfall models are discussed in relation to ski-slope planning and high-altitude road snow clearing. An application of the model to wind energy production planning is presented.
Buch, Mundó Ignasi 1984. "Investigation of protein-ligand interactions using high-throughput all-atom molecular dynamics simulations." Doctoral thesis, Universitat Pompeu Fabra, 2012. http://hdl.handle.net/10803/101407.
Повний текст джерелаGao, Yiran. "Dynamic inter-domain distributed computing." Thesis, Queen Mary, University of London, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.510898.
Повний текст джерелаKelley, Ian Robert. "Data management in dynamic distributed computing environments." Thesis, Cardiff University, 2012. http://orca.cf.ac.uk/44477/.
Повний текст джерелаFletcher, Luke. "A Dynamic Networked Browser Environment for Distributed Computing." Thesis, Honours thesis, University of Tasmania, 2002. https://eprints.utas.edu.au/38/1/Java_Distributed_Net_Thesis.pdf.
Повний текст джерелаLepler, Joerg. "Creating dynamic application behavior for distributed performance analysis." Thesis, Georgia Institute of Technology, 1998. http://hdl.handle.net/1853/8201.
Повний текст джерелаTosi, Riccardo. "Towards stochastic methods in CFD for engineering applications." Doctoral thesis, Universitat Politècnica de Catalunya, 2021. http://hdl.handle.net/10803/673389.
Повний текст джерелаLos desarrollos relacionados con la computación de alto rendimiento de las últimas décadas permiten resolver problemas científicos actuales, utilizando métodos computacionales sofisticados. Sin embargo, es necesario asegurarse de la eficiencia de los métodos computacionales modernos, con el fin de explotar al máximo las capacidades tecnológicas. En esta tesis proponemos diferentes métodos, relacionados con la cuantificación de incertidumbres y el cálculo de alto rendimiento, con el fin de minimizar el tiempo de computación necesario para resolver las simulaciones y garantizar una alta fiabilidad. En concreto, resolvemos sistemas de dinámica de fluidos caracterizados por incertidumbres. En el campo de la dinámica de fluidos computacional existen diferentes tipos de incertidumbres. Nosotros consideramos, por ejemplo, la forma y la evolución en el tiempo de las condiciones de frontera, así como la aleatoriedad de las fuerzas externas que actúan sobre el sistema. Desde un punto de vista práctico, es necesario estimar valores estadísticos del flujo del fluido, cumpliendo los criterios de convergencia para garantizar la fiabilidad del método. Para cuantificar el efecto de las incertidumbres utilizamos métodos de Monte Carlo jerárquicos, también llamados hierarchical Monte Carlo methods. Estas estrategias tienen tres niveles de paralelización: entre los niveles de la jerarquía, entre los eventos de cada nivel y durante la resolución del evento. Proponemos agregar un nuevo nivel de paralelización, entre batches, en el cual cada batch es independiente de los demás y tiene su propia jerarquía, compuesta por niveles y eventos distribuidos en diferentes niveles. Definimos estos nuevos algoritmos como métodos de Monte Carlo asíncronos y jerárquicos, cuyos nombres equivalentes en inglés son asynchronous hierarchical Monte Carlo methods. También nos enfocamos en reducir el tiempo de computación necesario para calcular estimadores estadísticos de flujos de fluidos caóticos e incompresibles. Nuestro método consiste en reemplazar una única simulación de dinámica de fluidos, caracterizada por una ventana de tiempo prolongada, por el promedio de un conjunto de simulaciones independientes, caracterizadas por diferentes condiciones iniciales y una ventana de tiempo menor. Este conjunto de simulaciones se puede ejecutar en paralelo en superordenadores, reduciendo el tiempo de computación. El método de promedio de conjuntos se conoce como ensemble averaging. Analizando las diferentes contribuciones del error del estimador estadístico, identificamos dos términos: el error debido a las condiciones iniciales y el error estadístico. En esta tesis proponemos un método que minimiza el error debido a las condiciones iniciales, y en paralelo sugerimos varias estrategias para reducir el coste computacional de la simulación. Finalmente, proponemos una integración del método de Monte Carlo y del método de ensemble averaging, cuyo objetivo es reducir el tiempo de computación requerido para calcular estimadores estadísticos de problemas de dinámica de fluidos dependientes del tiempo, caóticos y estocásticos. Reemplazamos cada realización de Monte Carlo por un conjunto de realizaciones independientes, cada una caracterizada por el mismo evento aleatorio y diferentes condiciones iniciales. Consideramos y resolvemos diferentes sistemas físicos, todos relevantes en el campo de la dinámica de fluidos computacional, como problemas de flujo del viento alrededor de rascacielos o problemas de flujo potencial. Demostramos la precisión, eficiencia y efectividad de nuestras propuestas resolviendo estos ejemplos numéricos.
Gli sviluppi del calcolo ad alte prestazioni degli ultimi decenni permettono di risolvere problemi scientifici di grande attualità, utilizzando sofisticati metodi computazionali. È però necessario assicurarsi dell’efficienza di questi metodi, in modo da ottimizzare l’uso delle odierne conoscenze tecnologiche. A tal fine, in questa tesi proponiamo diversi metodi, tutti inerenti ai temi di quantificazione di incertezze e calcolo ad alte prestazioni. L’obiettivo è minimizzare il tempo necessario per risolvere le simulazioni e garantire alta affidabilità. Nello specifico, utilizziamo queste strategie per risolvere sistemi fluidodinamici caratterizzati da incertezze in macchine ad alte prestazioni. Nel campo della fluidodinamica computazionale esistono diverse tipologie di incertezze. In questo lavoro consideriamo, ad esempio, il valore e l’evoluzione temporale delle condizioni di contorno, così come l’aleatorietà delle forze esterne che agiscono sul sistema fisico. Dal punto di vista pratico, è necessario calcolare una stima delle variabili statistiche del flusso del fluido, soddisfacendo criteri di convergenza, i quali garantiscono l’accuratezza del metodo. Per quantificare l’effetto delle incertezze sul sistema utilizziamo metodi gerarchici di Monte Carlo, detti anche hierarchical Monte Carlo methods. Queste strategie presentano tre livelli di parallelizzazione: tra i livelli della gerarchia, tra gli eventi di ciascun livello e durante la risoluzione del singolo evento. Proponiamo di aggiungere un nuovo livello di parallelizzazione, tra gruppi (batches), in cui ogni batch sia indipendente dagli altri ed abbia una propria gerarchia, composta da livelli e da eventi distribuiti su diversi livelli. Definiamo questi nuovi algoritmi come metodi asincroni e gerarchici di Monte Carlo, il cui corrispondente in inglese è asynchronous hierarchical Monte Carlo methods. Ci focalizziamo inoltre sulla riduzione del tempo di calcolo necessario per stimare variabili statistiche di flussi caotici ed incomprimibili. Il nostro metodo consiste nel sostituire un’unica simulazione fluidodinamica, caratterizzata da un lungo arco temporale, con il valore medio di un insieme di simulazioni indipendenti, caratterizzate da diverse condizioni iniziali ed un arco temporale minore. Questo insieme 10 di simulazioni può essere eseguito in parallelo in un supercomputer, riducendo il tempo di calcolo. Questo metodo è noto come media di un insieme o, in inglese, ensemble averaging. Calcolando la stima di variabili statistiche, commettiamo due errori: l’errore dovuto alle condizioni iniziali e l’errore statistico. In questa tesi proponiamo un metodo per minimizzare l’errore dovuto alle condizioni iniziali, ed in parallelo suggeriamo diverse strategie per ridurre il costo computazionale della simulazione. Infine, proponiamo un’integrazione del metodo di Monte Carlo e del metodo di ensemble averaging, il cui obiettivo è ridurre il tempo di calcolo necessario per stimare variabili statistiche di problemi di fluidodinamica dipendenti dal tempo, caotici e stocastici. Ogni realizzazione di Monte Carlo è sostituita da un insieme di simulazioni indipendenti, ciascuna caratterizzata dallo stesso evento casuale, da differenti condizioni iniziali e da un arco temporale minore. Consideriamo e risolviamo differenti sistemi fisici, tutti rilevanti nel campo della fluidodinamica computazionale, come per esempio problemi di flusso del vento attorno a grattacieli, o sistemi di flusso potenziale. Dimostriamo l’accuratezza, l’efficienza e l’efficacia delle nostre proposte, risolvendo questi esempi numerici.
Enginyeria civil
Azevedo, Perdicoulis Teresa-Paula C. "A distributed model for dynamic optimisation of networks." Thesis, University of Salford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300499.
Повний текст джерелаKaya, Ozgur. "Efficient Scheduling In Distributed Computing On Grid." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607928/index.pdf.
Повний текст джерелаDramlitsch, Thomas. "Distributed computations in a dynamic, heterogeneous Grid environment." Phd thesis, Universität Potsdam, 2002. http://opus.kobv.de/ubp/volltexte/2005/79/.
Повний текст джерелаJe nach Art der Problemstellung und des Lösungsverfahrens gestalten sich solche "Meta-Berechnungen" mehr oder weniger schwierig. Allgemein kann man sagen, dass solche Berechnungen um so schwerer und auch um so uneffizienter werden, je mehr Kommunikation zwischen den einzelnen Prozessen (oder Prozessoren) herrscht. Dies ist dadurch begründet, dass die Bandbreiten bzw. Latenzzeiten zwischen zwei Prozessoren auf demselben Grossrechner oder Cluster um zwei bis vier Grössenordnungen höher bzw. niedriger liegen als zwischen Prozessoren, welche hunderte von Kilometern entfernt liegen.
Dennoch bricht nunmehr eine Zeit an, in der es möglich ist Berechnungen auf solch virtuellen Supercomputern auch mit kommunikationsintensiven Programmen durchzuführen. Eine grosse Klasse von kommunikations- und berechnungsintensiven Programmen ist diejenige, die die Lösung von Differentialgleichungen mithilfe von finiten Differenzen zum Inhalt hat. Gerade diese Klasse von Programmen und deren Betrieb in einem virtuellen Superrechner wird in dieser vorliegenden Dissertation behandelt. Methoden zur effizienteren Durchführung von solch verteilten Berechnungen werden entwickelt, analysiert und implementiert. Der Schwerpunkt liegt darin vorhandene, klassische Parallelisierungsalgorithmen zu analysieren und so zu erweitern, dass sie vorhandene Informationen (z.B. verfügbar durch das Globus Toolkit) über Maschinen und Netzwerke zur effizienteren Parallelisierung nutzen. Soweit wir wissen werden solche Zusatzinformationen kaum in relevanten Programmen genutzt, da der Grossteil aller Parallelisierungsalgorithmen implizit für die Ausführung auf Grossrechnern oder Clustern entwickelt wurde.
In order to face the rapidly increasing need for computational resources of various scientific and engineering applications one has to think of new ways to make more efficient use of the worlds current computational resources. In this respect, the growing speed of wide area networks made a new kind of distributed computing possible: Metacomputing or (distributed) Grid computing. This is a rather new and uncharted field in computational science. The rapidly increasing speed of networks even outperforms the average increase of processor speed: Processor speeds double on average each 18 month whereas network bandwidths double every 9 months. Due to this development of local and wide area networks Grid computing will certainly play a key role in the future of parallel computing.
This type of distributed computing, however, distinguishes from the traditional parallel computing in many ways since it has to deal with many problems not occurring in classical parallel computing. Those problems are for example heterogeneity, authentication and slow networks to mention only a few. Some of those problems, e.g. the allocation of distributed resources along with the providing of information about these resources to the application have been already attacked by the Globus software.
Unfortunately, as far as we know, hardly any application or middle-ware software takes advantage of this information, since most parallelizing algorithms for finite differencing codes are implicitly designed for single supercomputer or cluster execution. We show that although it is possible to apply classical parallelizing algorithms in a Grid environment, in most cases the observed efficiency of the executed code is very poor.
In this work we are closing this gap. In our thesis, we will
- show that an execution of classical parallel codes in Grid environments is possible but very slow
- analyze this situation of bad performance, nail down bottlenecks in communication, remove unnecessary overhead and other reasons for low performance
- develop new and advanced algorithms for parallelisation that are aware of a Grid environment in order to generelize the traditional parallelization schemes
- implement and test these new methods, replace and compare with the classical ones - introduce dynamic strategies that automatically adapt the running code to the nature of the underlying Grid environment.
The higher the performance one can achieve for a single application by manual tuning for a Grid environment, the lower the chance that those changes are widely applicable to other programs. In our analysis as well as in our implementation we tried to keep the balance between high performance and generality. None of our changes directly affect code on the application level which makes our algorithms applicable to a whole class of real world applications.
The implementation of our work is done within the Cactus framework using the Globus toolkit, since we think that these are the most reliable and advanced programming frameworks for supporting computations in Grid environments. On the other hand, however, we tried to be as general as possible, i.e. all methods and algorithms discussed in this thesis are independent of Cactus or Globus.
Yu, Lihua. "Optimization of multi-scale decision-oriented dynamic systems and distributed computing." Diss., The University of Arizona, 2004. http://hdl.handle.net/10150/280505.
Повний текст джерелаHusain, Rashid, and Syed Muhammad Husnain Kazmi. "Comparative Analysis of Static Recovery Schemes for Distributed Computing." Thesis, Blekinge Tekniska Högskola, Avdelningen för för interaktion och systemdesign, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-4805.
Повний текст джерела0046735991980, 0046766503096
Hernandez, Jesus Israel. "Reactive scheduling of DAG applications on heterogeneous and dynamic distributed computing systems." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/2336.
Повний текст джерелаNeal, Stephen. "A language for the dynamic verification of design patterns in distributed computing." Thesis, University of Kent, 2001. https://kar.kent.ac.uk/13532/.
Повний текст джерелаRamesh, Vasanth Kumar. "A game theoretic framework for dynamic task scheduling in distributed heterogeneous computing systems." [Tampa, Fla.] : University of South Florida, 2005. http://purl.fcla.edu/fcla/etd/SFE0001115.
Повний текст джерелаde, Carvalho Tiago Filipe Rodrigues. "Integrated Approach to Dynamic and Distributed Cloud Data Center Management." Research Showcase @ CMU, 2016. http://repository.cmu.edu/dissertations/739.
Повний текст джерелаSvärd, Petter. "Dynamic Cloud Resource Management : Scheduling, Migration and Server Disaggregation." Doctoral thesis, Umeå universitet, Institutionen för datavetenskap, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-87904.
Повний текст джерелаHelal, Manal Computer Science & Engineering Faculty of Engineering UNSW. "Indexing and partitioning schemes for distributed tensor computing with application to multiple sequence alignment." Awarded by:University of New South Wales. Computer Science & Engineering, 2009. http://handle.unsw.edu.au/1959.4/44781.
Повний текст джерелаGlacet, Christian. "Algorithmes de routage : de la réduction des coûts de communication à la dynamique." Phd thesis, Université Sciences et Technologies - Bordeaux I, 2013. http://tel.archives-ouvertes.fr/tel-00951393.
Повний текст джерелаDe, Grande Robson E. "Dynamic Load Balancing Schemes for Large-scale HLA-based Simulations." Thèse, Université d'Ottawa / University of Ottawa, 2012. http://hdl.handle.net/10393/23110.
Повний текст джерелаHari, Krishnan Prem Kumar. "Design and Analysis of a Dynamic SpaceWire Routing Protocol for Reconfigurable and Distributed On-Board Computing Systems". Thesis, Luleå tekniska universitet, Rymdteknik, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-76534.
Повний текст джерелаBalasubramaniam, Mahadevan. "Performance analysis and evaluation of dynamic loop scheduling techniques in a competitive runtime environment for distributed memory architectures." Master's thesis, Mississippi State : Mississippi State University, 2003. http://library.msstate.edu/etd/show.asp?etd=etd-04022003-154254.
Повний текст джерелаKotto, Kombi Roland. "Distributed query processing over fluctuating streams." Thesis, Lyon, 2018. http://www.theses.fr/2018LYSEI050/document.
Повний текст джерелаIn a Big Data context, stream processing has become a very active research domain. In order to manage ephemeral data (Velocity) arriving at important rates (Volume), some specific solutions, denoted data stream management systems (DSMSs),have been developed. DSMSs take as inputs some queries, called continuous queries,defined on a set of data streams. Acontinuous query generates new results as long as new data arrive in input. In many application domains, data streams haveinput rates and distribution of values which change over time. These variations may impact significantly processingrequirements for each continuous query.This thesis takes place in the ANR project Socioplug (ANR-13-INFR-0003). In this context, we consider a collaborative platformfor stream processing. Each user can submit multiple continuous queries and contributes to the execution support of theplatform. However, as each processing unit supporting treatments has limited resources in terms of CPU and memory, asignificant increase in input rate may cause the congestion of the system. The problem is then how to adjust dynamicallyresource usage to processing requirements for each continuous query ? It raises several challenges : i) how to detect a need ofreconfiguration ? ii) when reconfiguring the system to avoid its congestion at runtime ?In this work, we are interested by the different processing steps involved in the treatment of a continuous query over adistributed infrastructure. From this global analysis, we extract mechanisms enabling dynamic adaptation of resource usage foreach continuous query. We focus on automatic parallelization, or auto-parallelization, of operators composing the executionplan of a continuous query. We suggest an original approach based on the monitoring of operators and an estimation ofprocessing requirements in near future. Thus, we can increase (scale-out), or decrease (scale-in) the parallelism degree ofoperators in a proactive many such as resource usage fits to processing requirements dynamically. Compared to a staticconfiguration defined by an expert, we show that it is possible to avoid the congestion of the system in many cases or to delay itin most critical cases. Moreover, we show that resource usage can be reduced significantly while delivering equivalentthroughput and result quality. We suggest also to combine this approach with complementary mechanisms for dynamic adaptation of continuous queries at runtime. These differents approaches have been implemented within a widely used DSMS and have been tested over multiple and reproductible micro-benchmarks
Subbiah, Arun. "Design and evaluation of a distributed diagnosis algorithm for arbitrary network topologies in dynamic fault environments." Thesis, Georgia Institute of Technology, 2001. http://hdl.handle.net/1853/13273.
Повний текст джерелаEdirisinghe, Pathirannehelage Neranjan S. "Charge Transfer in Deoxyribonucleic Acid (DNA): Static Disorder, Dynamic Fluctuations and Complex Kinetic." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/phy_astr_diss/45.
Повний текст джерелаVijayakumar, Smita. "A Framework for Providing Automatic Resource and Accuracy Management in a Cloud Environment." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1274194090.
Повний текст джерелаVillebonnet, Violaine. "Scheduling and Dynamic Provisioning for Energy Proportional Heterogeneous Infrastructures." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEN057/document.
Повний текст джерелаThe increasing number of data centers raises serious concerns regarding their energy consumption. These infrastructures are often over-provisioned and contain servers that are not fully utilized. The problem is that inactive servers can consume as high as 50% of their peak power consumption.This thesis proposes a novel approach for building data centers so that their energy consumption is proportional to the actual load. We propose an original infrastructure named BML for "Big, Medium, Little", composed of heterogeneous computing resources : from low power processors to classical servers. The idea is to take advantage of their different characteristics in terms of energy consumption, performance, and switch on reactivity to adjust the composition of the infrastructure according to the load evolutions. We define a generic methodology to compute the most energy proportional combinations of machines based on hardware profiling data.We focus on web applications whose load varies over time and design a scheduler that dynamically reconfigures the infrastructure, with application migrations and machines switch on and off, to minimize the infrastructure energy consumption according to the current application requirements.We have developed two different dynamic provisioning algorithms which take into account the time and energy overheads of the different reconfiguration actions in the decision process. We demonstrate through simulations based on experimentally acquired hardware profiles that we achieve important energy savings compared to classical data center infrastructures and management
Tesser, Rafael Keller. "A simulation workflow to evaluate the performance of dynamic load balancing with over decomposition for iterative parallel applications." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2018. http://hdl.handle.net/10183/180129.
Повний текст джерелаIn this thesis we present a novel simulation workflow to evaluate the performance of dynamic load balancing with over-decomposition applied to iterative parallel applications at low-cost. Its goals are to perform such evaluation with minimal application modification and at a low cost in terms of time and of resource requirements. Many parallel applications suffer from dynamic (temporal) load imbalance that can not be treated at the application level. It may be caused by intrinsic characteristics of the application or by external software and hardware factors. As demonstrated in this thesis, such dynamic imbalance can be found even in applications whose codes do not hint at any dynamism. Therefore, we need to rely on runtime dynamic load balancing mechanisms, such as dynamic load balancing based on over-decomposition. The problem is that evaluating and tuning the performance of such technique can be costly. This usually entails modifications to the application and a large number of executions to get statistically sound performance measurements with different load balancing parameter combinations. Moreover, useful and accurate measurements often require big resource allocations on a production cluster. Our simulation workflow, dubbed Simulated Adaptive MPI (SAMPI), employs a combined sequential emulation and trace-replay simulation approach to reduce the cost of such an evaluation Both sequential emulation and trace-replay require a single computer node. Additionally, the trace-replay simulation lasts a small fraction of the real-life parallel execution time of the application. Besides the basic SAMPI simulation, we developed spatial aggregation and applicationlevel rescaling techniques to speed-up the emulation process. To demonstrate the real-life performance benefits of dynamic load balance with over-decomposition, we evaluated the performance gains obtained by employing this technique on a iterative parallel geophysics application, called Ondes3D. Dynamic load balancing support was provided by Adaptive MPI (AMPI). This resulted in up to 36.58% performance improvement, on 288 cores of a cluster. This real-life evaluation also illustrates the difficulties found in this process, thus justifying the use of simulation. To implement the SAMPI workflow, we relied on SimGrid’s Simulated MPI (SMPI) interface in both emulation and trace-replay modes.To validate our simulator, we compared simulated (SAMPI) and real-life (AMPI) executions of Ondes3D. The simulations presented a load balance evolution very similar to real-life and were also successful in choosing the best load balancing heuristic for each scenario. Besides the validation, we demonstrate the use of SAMPI for load balancing parameter exploration and for computational capacity planning. As for the performance of the simulation itself, we roughly estimate that our full workflow can simulate the execution of Ondes3D with 24 different load balancing parameter combinations in 5 hours for our heavier earthquake scenario and in 3 hours for the lighter one.
Bartoň, Radek. "Modernizace GIS systému GRASS." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235885.
Повний текст джерелаKwon, Young Woo. "Effective Fusion and Separation of Distribution, Fault-Tolerance, and Energy-Efficiency Concerns." Diss., Virginia Tech, 2014. http://hdl.handle.net/10919/49386.
Повний текст джерелаPh. D.
Xiong, Pengcheng. "Dynamic monitoring, modeling and management of performance and resources for applications in cloud." Diss., Georgia Institute of Technology, 2012. http://hdl.handle.net/1853/45779.
Повний текст джерелаSun, Yi. "High Performance Simulation of DEVS Based Large Scale Cellular Space Models." Digital Archive @ GSU, 2009. http://digitalarchive.gsu.edu/cs_diss/40.
Повний текст джерелаDodonov, Evgueni. "Uma abordagem de predição da dinâmica comportamental de processos para prover autonomia a ambientes distribuídos." Universidade de São Paulo, 2009. http://www.teses.usp.br/teses/disponiveis/55/55134/tde-05082009-205709/.
Повний текст джерелаThe evolution of distributed systems resulted in a significant growth in management and support complexities, which uncovered the inefficiencies incurred by the usage of conventional management techniques, based in manual interventions. This, therefore, has motivated researches towards the concept of Autonomic Computing, which provides aspects of self-configuration, self-healing, self-optimization and self-protection, aiming at developing computer systems capable of self-management. In this context, this thesis was conceived with the goal of providing autonomy to distributed systems, without changing the programming paradigm or user applications. In order to reach this goal, we proposed an approach which employs techniques capable of modelling and predicting the dynamics of application behavior, using concepts introduced in dynamical systems, artificial intelligence, and chaos theory. The obtained results demonstrated that it is possible to optimize several aspects of distributed computing, providing support for autonomic computing capabilities to distributed environments. In order to validate the proposed approach, a distributed scheduling policy was developed, named PredRoute, which uses the knowledge about the process behavior to transparently optimize the resource allocation. Experimental results demonstrated that this policy can improve the system performance by up to a power of 4, and also requires a considerably low computational cost, which suggests its adoption for online process scheduling in distributed environments
Meslmawy, Mahdi Abed Salman. "Efficient ressources management in a ditributed computer system, modeled as a dynamic complex system." Thesis, Le Havre, 2015. http://www.theses.fr/2015LEHA0007/document.
Повний текст джерелаGrids and clouds are types of currently widely known distributed computing systems or DCSs. DCSs are complex systems in the sense that their emergent global behavior results from decentralized interaction of its parts and is not guided directly from a central point. In our study, we present a complex system model that efficiently manages the ressources of a DCS. The entities of the DCS react to system instability and adjust their environmental condtions for optimizing system performance. The structure of the interaction networks that allow fast and reliable access to available resources is studied and improvements ar proposed
Neto, Benedito Josà de Almeida. "SYSSU-DTS: um sistema de suporte à computaÃÃo ubÃqua baseado em espaÃo de tuplas distribuÃdo." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12677.
Повний текст джерелаnÃo hÃ
A evoluÃÃo das tecnologias mÃveis favorece o surgimento de sistemas capazes de antever as necessidades do usuÃrio e se adaptar Ãs variaÃÃes de seu contexto de forma imperceptÃvel. Tais sistemas, denominados sistemas ubÃquos, enfrentam o desafio da adaptaÃÃo dinÃmica em um cenÃrio altamente distribuÃdo, heterogÃneo e volÃtil, uma vez que pode se tornar difÃcil coletar e processar informaÃÃes contextuais oriundas de fontes desconhecidas e distribuÃdas. O problema em questÃo à o gerenciamento de dados contextuais em cenÃrios sujeitos a mobilidade e conexÃes intermitentes entre dispositivos mÃveis e servidores. A fim de facilitar o desenvolvimento de sistemas ubÃquos, este trabalho estende um sistema de suporte existente, chamado SysSU (LIMA et al., 2011), que foi baseado em espaÃos de tuplas centralizado. Com o objetivo de gerenciar informaÃÃes de contexto distribuÃdas, à adotada uma abordagem de espaÃo de tuplas descentralizada, oferecendo aos componentes dos sistemas ubÃquos a capacidade de interaÃÃo e cooperaÃÃo em situaÃÃes de total descentralizaÃÃo. Sendo assim, esta dissertaÃÃo propÃe o SysSU-DTS (System Support for Ubiquity - Distribute Tuple Space), um sistema de suporte que fornece a funcionalidade de coordenaÃÃo de sistemas ubÃquos em ambientes abertos, onde nenhuma suposiÃÃo sobre os recursos disponÃveis deve ser feita. O SysSU-DTS à focado em sistemas ubÃquos baseado em dispositivos mÃveis, como smartphones, tablets e ultrabooks, que podem se comunicar atravÃs de redes mÃveis Ad hoc (MANET - Mobile Ad hoc Network). O SysSU-DTS representa informaÃÃes contextuais por meio de tuplas e permite o acesso transparente a informaÃÃes de contexto disponÃveis, estejam elas localizadas dentro do dispositivo mÃvel, em um servidor ou em outro dispositivo mÃvel prÃximo. A partir do acesso a informaÃÃes de contexto oriundas de diferentes provedores, as aplicaÃÃes ubÃquas e sensÃveis ao contexto que adotem o suporte do SysSU-DTS podem ter uma visÃo do contexto global das entidades envolvidas no sistema. AlÃm disso, o SysSU-DTS implementa um mecanismo de escopo que permite a formaÃÃo de subconjuntos de informaÃÃes contextuais disponÃveis, evitando gerenciamento de informaÃÃes desnecessÃrias. SÃo apresentados resultados experimentais obtidos em uma avaliaÃÃo de desempenho realizada em um testbed composto por smartphones e tablets. Esta avaliaÃÃo demonstra a viabilidade prÃtica da abordagem proposta e como o SysSU-DTS promove a distribuiÃÃo de informaÃÃes de contexto adaptando-se dinamicamente a provedores de contexto locais, infra-estruturados e distribuÃdos em redes Ad hoc.
The evolution of mobile technologies allows the emerging of ubiquitous systems, able to anticipate userâs needs and to seamlessly adapt to context changes. These systems present the problem of dynamic adaptation in a highly distributed, heterogeneous and volatile environment, since it may be difficult to collect and process context information from distributed unknown sources. The problem faced is the management of contextual data in scenarios with mobility and intermittent connections between mobile devices and servers. In order to facilitate the development of such systems, this work extends an existing support system based on centralized tuple spaces, called SysSU (LIMA et al., 2011), aiming at the management of distributed information. Hence, a decentralized tuple space approach is adopted, offering to ubiquitous systems components the capability of interaction and cooperation in scenarios of total decentralization. Thus, this work introduces SysSU-DTS (System Support for Ubiquity - Distribute Tuple Space), a system support that provides functionality for coordinating ubiquitous systems in open environments, where no assumptions about available resources should be made. It focuses on ubiquitous systems based on mobile devices such as smartphones, tablets and ultrabooks, which can communicate through a Mobile Ad hoc Network (MANET). SysSU-DTS represents context information by tuples and allows a transparent access to spread context, as follows: (i)local access, which accesses an internal device tuple space; (ii) infrastructured access, tuple spaces located on a server accessed using an infrastructured network; or (iii) Ad hoc access, interacting directly with tuple spaces located in nearby devices via the formation of an Ad hoc network. From the access to different context providers, ubiquitous and context-aware applications, using SysSU-DTSs support, can have an insight of global context related to the system entities. In addition, SysSU-DTS implements a scope mechanism that allows the formation of available contextual information subsets. This mechanism restricts access to contextual tuples only to members of the same scope, avoiding unnecessary information management. This dissertation reports some experimental results obtained in a performance evaluation using a testbed of smartphones and tablets. The evaluation shows the practical feasibility of our approach and point out how SysSU-DTS can grant context data distribution with dynamically adapting to local, infrastructured and distributed over Ad hoc networks context providers.
Cyriac, Aiswarya, and Aiswarya Cyriac. "Verification of communicating recursive programs via split-width." Phd thesis, École normale supérieure de Cachan - ENS Cachan, 2014. http://tel.archives-ouvertes.fr/tel-01015561.
Повний текст джерелаShoker, Ali. "Byzantine fault tolerance from static selection to dynamic switching." Toulouse 3, 2012. http://thesesups.ups-tlse.fr/1924/.
Повний текст джерелаByzantine Fault Tolerance (BFT) is becoming crucial with the revolution of online applications and due to the increasing number of innovations in computer technologies. Although dozens of BFT protocols have been introduced in the previous decade, their adoption by practitioners sounds disappointing. To some extant, this indicates that existing protocols are, perhaps, not yet too convincing or satisfactory. The problem is that researchers are still trying to establish 'the best protocol' using traditional methods, e. G. , through designing new protocols. However, theoretical and experimental analyses demonstrate that it is hard to achieve one-size-fits-all BFT protocols. Indeed, we believe that looking for smarter tac-tics like 'fasten fragile sticks with a rope to achieve a solid stick' is necessary to circumvent the issue. In this thesis, we introduce the first BFT selection model and algorithm that automate and simplify the election process of the 'preferred' BFT protocol among a set of candidate ones. The selection mechanism operates in three modes: Static, Dynamic, and Heuristic. For the two latter modes, we present a novel BFT system, called Adapt, that reacts to any potential changes in the system conditions and switches dynamically between existing BFT protocols, i. E. , seeking adaptation. The Static mode allows BFT users to choose a single BFT protocol only once. This is quite useful in Web Services and Clouds where BFT can be sold as a service (and signed in the SLA contract). This mode is basically designed for systems that do not have too fuctuating states. In this mode, an evaluation process is in charge of matching the user preferences against the profiles of the nominated BFT protocols considering both: reliability, and performance. The elected protocol is the one that achieves the highest evaluation score. The mechanism is well automated via mathematical matrices, and produces selections that are reasonable and close to reality. Some systems, however, may experience fluttering conditions, like variable contention or message payloads. In this case, the static mode will not be e?cient since a chosen protocol might not fit the new conditions. The Dynamic mode solves this issue. Adapt combines a collection of BFT protocols and switches between them, thus, adapting to the changes of the underlying system state. Consequently, the 'preferred' protocol is always polled for each system state. This yields an optimal quality of service, i. E. , reliability and performance. Adapt monitors the system state through its Event System, and uses a Support Vector Regression method to conduct run time predictions for the performance of the protocols (e. G. , throughput, latency, etc). Adapt also operates in a Heuristic mode. Using predefined heuristics, this mode optimizes user preferences to improve the selection process. The evaluation of our approach shows that selecting the 'preferred' protocol is automated and close to reality in the static mode. In the Dynamic mode, Adapt always achieves the optimal performance among available protocols. The evaluation demonstrates that the overall system performance can be improved significantly too. Other cases explore that it is not always worthy to switch between protocols. This is made possible through conducting predictions with high accuracy, that can reach more than 98% in many cases. Finally, the thesis shows that Adapt can be smarter through using heursitics
Lagarde, Matthieu, Philippe Gaussier, and Pierre Andry. "Apprentissage de nouveaux comportements: vers le développement épigénétique d'un robot autonome." Phd thesis, Université de Cergy Pontoise, 2010. http://tel.archives-ouvertes.fr/tel-00749761.
Повний текст джерелаMendonça, Rafael Mathias de. "Algoritmos distribuídos para alocação dinâmica de tarefas em enxame de robôs." Universidade do Estado do Rio de Janeiro, 2014. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=8140.
Повний текст джерелаSwarm Intelligence has been proposed based on the observation of social behavior of insect species, birds and fishes. The main idea of this collective behavior is to perform a complex task decomposing it into many simple tasks, that can be easily performed by individuals of the swarm. Coordinated realization of these simple tasks while adhering to a pre-defined distribution of execution, allows for the achievement of the original complex task. The problem of task allocation arises from the need of assigning tasks to individuals in a coordinated fashion, allowing a good management of the swarm. Task allocation is a dynamic process because it requires a continuous adjustment in response to changes in the environment, the swarm configuration and/or the performance of the swarm. Swarm robotics emerges from this context of collective cooperation applied to swarms of real robots. In this approach, complex problems are solved by performing complex tasks using swarms of simple robots, with a limited processing and communication capabilities. Aiming at achieving flexibility and reliability, the allocation should emerge as a result of a distributed process. With the decentralization of the problem and the increasing number of robots in the swarm, the allocation process acquires a high complexity. Thus, the problem of task allocation can be characterized as an optimization process that assigns tasks to robots, so that the desired proportion is met at the end of the optimization process, find the desired solution. In this dissertation, we propose two algorithms that follow different to the problem of dynamic task allocation approaches: one is local and the other global. The algorithm for dynamic allocation of tasks with a local approach (ADTL) updates the task assignment of each robot based on a deterministic assessment of the current knowledge it has so far about the tasks allocated to the other robots of the swarm. The algorithm for dynamic task allocation with a global approach (ADTG) updates the allocation of tasks based on a swarm optimization process, inspired by PSO (Particle swarm optimization). In ADTG, each robot has a possible solution to the swarm allocation, which is continuously updated through the exchange of information between the robots. The allocations are evaluated for their fitness in meeting the goal proportion. When the allocation of highest fitness in the swarm is identified, all robots of the swarm are allocated to the tasks defined by this allocation. The proposed algorithms were implemented on swarms of different arrangements of real robots demonstrating their efficacy, robustness and efficiency, certified by obtained the results.
Mastio, Matthieu. "Modèles de distribution pour la simulation de trafic multi-agent." Thesis, Paris Est, 2017. http://www.theses.fr/2017PESC1147/document.
Повний текст джерелаNowadays, analysis and prediction of transport network behavior are crucial elements for the implementation of territorial management policies. Computer simulation of road traffic is a powerful tool for testing management strategies before deploying them in an operational context. Simulation of city-wide traffic requires significant computing power exceeding the capacity of a single computer.This thesis studies the methods to perform large-scale multi-agent traffic simulations. We propose solutions allowing the distribution of such simulations on a large amount of computing cores.One of them distributes the agents directly on the available cores, while the second splits the environment on which the agents evolve. Graph partitioning methods are studied for this purpose, and we propose a partitioning procedure specially adapted to the multi-agent traffic simulation. A dynamic load balancing algorithm is also developed to optimize the performance of the microscopic simulation distribution.The proposed solutions have been tested on a real network representing the Paris-Saclay area.These solutions are generic and can be applied to most existing simulators.The results show that the distribution of the agents greatly improves the performance of the macroscopic simulation, whereas the environment distribution is more suited to microscopic simulation. Our load balancing algorithm also significantly improves the efficiency of the environment based distribution
Ruiz, Anthony. "Simulations Numériques Instationnaires de la Combustion Turbulente et Transcritique dans les Moteurs Cryotechniques." Phd thesis, Institut National Polytechnique de Toulouse - INPT, 2012. http://tel.archives-ouvertes.fr/tel-00691975.
Повний текст джерелаJimborean, Alexandra. "Adapting the polytope model for dynamic and speculative parallelization." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00733850.
Повний текст джерелаLachat, Cédric. "Conception et validation d'algorithmes de remaillage parallèles à mémoire distribuée basés sur un remailleur séquentiel." Phd thesis, Université Nice Sophia Antipolis, 2013. http://tel.archives-ouvertes.fr/tel-00932602.
Повний текст джерелаTaton, Christophe. "Vers l’auto-optimisation dans les systèmes autonomes." Grenoble INPG, 2008. http://www.theses.fr/2008INPG0183.
Повний текст джерелаThe increasing complexity of computer systems makes their administration even more tedious and error-prone. A general approach to this problem consists in building autonomic systems that are able to manage themselves and to handle changes of their state and their environment. While energy becomes even more scarce and expensive, the optimization of computer systems is an essential management field to improve their performance and to reduce their energetic footprint. As huge energy consumers, current computer systems are usually statically configured and behave badly in response to changes of their environment, and especially to changes of their workload. Self-optimization appears as a promising approach to these problems as it endows these systems with the ability to improve their own performance in an autonomous manner. This thesis focuses on algorithms and techniques to implement self-optimized autonomic systems. We specifically study self-optimization algorithms that rely on dynamic system provisioning in order to improve their performance and their resources’ efficiency. In the context of the Jade prototype of a component-based autonomic management platform, we propose best-effort algorithms that improve the performance of the managed systems through dynamic adaptations of the systems in response to gradual or sudden changes of their workload. We show the efficiency of these algorithms on Internet services and on messages services submitted to changing workloads. Finally, in order to guarantee optimal performance, we propose an optimization policy relying on the modelling of the managed system so as to generate optimal configurations. This policy is evaluated on a monitoring service for distributed systems. The implementation of autonomic management policies raised a number of challenges: the system is required to support dynamic adaptions, to observe itself and to take actions on itself. We address these needs with the Oz programming language and its distributed platform Mozart to implement the FructOz framework dedicated to the construction and handling of complex dynamic and distributed architecture-based systems, and the LactOz library specialized in the querying and browsing of dynamic architectures. Combining FructOz and LactOz, we show how to build complex dynamic systems involving distributed deployments as well as high levels of synchronizations and parameters
Guyeux, Christophe. "Désordre des itérations chaotiques et leur utilité en sécurité informatique." Besançon, 2010. http://www.theses.fr/2010BESA2019.
Повний текст джерелаFor the first time, the divergence and disorder properties of “chaotic iterations”, a tool taken from the discrete mathematics domain, are studied. After having used discrete mathematics to deduce situations of non-convergence, these iterations are modeled as a dynamical system and are topologically studied into the framework of the mathematical theory of chaos. We prove that their adjective “chaotic” is well chosen : these iterations are chaotic, according to the definitions of Devaney, Li-Yorke, expansivity, topological entropy, Lyapunov exponent, and so on. These properties have been established for a topology different from the order topology, thus the consequences of this choice are discussed. We show that these chaotic iterations can be computed without any loss of properties, and that it is possible to circumvent the problem of the finiteness of computers to obtain programs that are proven to be chaotic according to Devaney, etc. The procedure proposed in this document is followed to generate a digital watermarking algorithm and a hash function, which are chaotic according to the strongest possible sense. At each time, the advantages of being chaotic as defined in the mathematical theory of chaos is justified, the properties to check are chosen depending on the objectives to reach, and the programs are evaluated. A novel notion of security for steganography is introduced, to address the lack of tool for estimating the strength of an information hiding scheme against certain types of attacks. Finally, two solutions to the problem of secure data aggregation in wireless sensor networks are proposed
NATALE, EMANUELE. "On the computational power of simple dynamics." Doctoral thesis, 2017. http://hdl.handle.net/11573/934053.
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