Dissertations / Theses on the topic 'Large Scale Systems'
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Nandy, Sagnik. "Large scale autonomous computing systems." Diss., Connected to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2005. http://wwwlib.umi.com/cr/ucsd/fullcit?p3190006.
Full textTitle from first page of PDF file (viewed March 7, 2006). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 120-128).
Aga, Svein. "System Recovery in Large-Scale Distributed Storage Systems." Thesis, Norwegian University of Science and Technology, Department of Computer and Information Science, 2008. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9724.
Full textThis report aims to describe and improve a system recovery process in large-scale storage systems. Inevitable, a recovery process results in the system being loaded with internal replication of data, and will extensively utilize several storage nodes. Such internal load can be categorized and generalized into a maintenance workload class. Obviously, a storage system will have external clients which also introduce load into the system. This can be users altering their data, uploading new content, etc. Load generated by clients can be generalized into a production workload class. When both workload classes are actively present in a system, i.e. the system is recovering while users are simultaneously accessing their data, there will be a competition of system resources between the different workload classes. The storage must ensure Quality of Service (QoS) for each workload class so that both are guaranteed system resources. We have created Dynamic Tree with Observed Metrics (DTOM), an algorithm designed to gracefully throttle resources between multiple different workload classes. DTOM can be used to enforce and ensure QoS for the variety of workloads in a system. Experimental results demonstrate that DTOM outperforms another well-known scheduling algorithm. In addition, we have designed a recovery model which aims to improve handling of critical maintenance workload. Although the model is intentionally intended for system recovery, it can also be applied to many other contexts.
El-Makadema, Ahmed Talal. "Large scale broadband antenna array systems." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/large-scale-broadband-antenna-array-systems(d2586bcf-4d2f-4046-98bf-90860b52565b).html.
Full textSales, Pardo Marta. "Large Scale Excitations in Disordered Systems." Doctoral thesis, Universitat de Barcelona, 2002. http://hdl.handle.net/10803/1786.
Full textThe existence of these large excitations brings about large fluctuations of the order parameter, and we have shown in these theses that this feature can be exploited to study the transition of any spin glass model. Moreover, we have shown that the information about these excitations can be extracted from the statistics of the lowest lying excitations. This is because due to the random nature of spin glasses, the physics obtained from averaging over the whole spectrum of excitations of an infinite sample is equivalent to averaging over many finite systems where only the ground state and the first excitation are considered. The novelty of this approach is that we do not need to make any assumption on what are typical excitations like because we can compute them exactly using numerical methods. Finally, we have investigated the dynamics and more specifically the link between the problem of chaos and the rejuvenation phenomena observed experimentally. Rejuvenation means that when lowering the temperature the aging process restarts again from scratch. This is potentially linked with the chaos assumption which states that equilibrium configurations at two different properties are not correlated. Chaos is a large scale phenomenon possible if entropy fluctuations are large. However, in this thesis we have shown that the response to temperature changes can be large in the absence of chaos close to a localization transition where the Boltzmann weight condenses in a few states. This has been observed in simulation of the Sinai model in which this localization is realized dynamically. In this model, since at low temperatures the system gets trapped in the very deep states, the dynamics is only local, so that only small excitations contribute to the rejuvenation signal that we have been able to observe. Thus, in agreement with the hierarchical picture, rejuvenation is possible even in the absence of chaos and reflects the start of the aging process of small length scales.
Djurfeldt, Mikael. "Large-scale simulation of neuronal systems." Doctoral thesis, KTH, Beräkningsbiologi, CB, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-10616.
Full textQC 20100722
D'Arcy, Francis Gerard. "State estimation for large-scale systems." Thesis, Queen's University Belfast, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.287436.
Full textLargillier, Thomas. "Probabilistic algorithms for large scale systems." Paris 11, 2010. http://www.theses.fr/2010PA112348.
Full textNowadays, information systems are getting bigger and bigger to remain able to manage users requirements. In scientific computing, networks are compound of more and more computers to solve more complex and bigger instances of problems, the internet is also increasing to satisfy the curiosity of all users and cover and increasing number of topics. The challenges regarding large-scale systems are numerous: guaranteeing clusters' users that their computation will finish in a reasonable time without errors, efficiently distributing data between small intelligent entities or protecting the web against malicious users. During this thesis, I participated in the design of mechanisms fighting webspam and social spam based on the identification of communities in large graphs. I also participated in the development of a testbed for massively parallel applications and in the design of a data dissemination protocol in wireless sensor networks
Ali, Asim. "Robustness in large scale distributed systems." Paris 11, 2010. http://www.theses.fr/2010PA112097.
Full textDuring the last decade, computing and communication technologies observed exponential growth both in hardware and software. The direct result of this growth is the emergence of global scale distributed systems like, information diffusion systems, cellular networks, remote computing, etc. Integration of sensor devices with networks helped to develop smart systems that are more interactive, dynamic and adaptable to the running environment. Future applications are envisioned as completely decentralized self-managing massive distributed systems running in smart environments on top of Internet or grid infrastructure. Such large-scale systems are difficult to design, develop and maintain due to many constraints like heterogeneity of resources, diverse working environments, unreliable communications, etc. Wireless sensor networks and computational grids are two important examples of such large-scale systems. Most desirable properties of the protocols for these networks include scalability, self-management, and fault tolerance. These are the three main areas this thesis focuses on. In this thesis we contribute to this domain in three ways. First we propose and evaluate a scalable directory management protocol for general distributed systems where update latency time is independent of the system size. In our second contribution we design and implement a scalable distributed version of an existing wireless network simulator: WSNet. We run our parallel simulator, XS-WSNet, on Grid5000 and achieve extreme simulation scalability. Our third contribution is the development of a dependability benchmarking mechanism for testing WSN protocols against fault and adversarial environments. Our tool allows the user to simulate natural faulty environments for WSN, like harsh weather conditions as well as to simulate dynamic attacks to the wireless network
Martin, Philippe J. F. "Large scale C3 systems : experiment design and system improvement." Thesis, Laboratory for Information and Decision Systems, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/15061.
Full textIncludes bibliographical references (p. 105-106).
Research supported by the Joint Directors of Laboratories through the Office of Naval Research. N00014-85-K-0782
Philippe J. F. Martin.
M.S.
Westfelt, Vidar, and Arturas Aleksandrauskas. "Automated migration of large-scale build systems." Thesis, Linköpings universitet, Institutionen för datavetenskap, 2019. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-157770.
Full textHenneman, Richard Lewis. "Human problem solving in complex hierarchical large scale systems." Diss., Georgia Institute of Technology, 1985. http://hdl.handle.net/1853/25432.
Full textResch, Matthias. "Large scale battery systems in distribution grids." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/665519.
Full textEl objetivo principal de la tesis es cuantificar hasta qué punto las medidas de expansión de la red pueden evitarse mediante el uso de baterías y en qué medida es posible el equilibrio entre una operación económica y la de apoyo a la red. Como parte del proyecto, que se investiga en esta tesis, un sistema prototipo de batería de vanadio redox flow a gran escala se integró por primera vez en la red eléctrica de un operador del sistema de distribución en Alemania. Un análisis preliminar de posibles modelos de negocio para grandes sistemas de baterías muestra que la aplicación de baterías en el mercado de energía de control primario es, con mucho, la aplicación más lucrativa en el marco alemán actual. Le sigue el uso de autoconsumo de energía fotovoltaica para reducir costes. Ambos casos comerciales se analizan en detalle. La tesis se centra en la aplicación de control primario de apoyo a la red. El apoyo de la red por parte de la batería se asegura a través de la regulación de la tensión en la red de baja tensión a través de un control de potencia reactiva. El sistema de batería desarrollado fue probado en la región piloto durante un periodo de un año. Ese prototipo y la red de la región piloto se modelaron en base a los datos medidos ese periodo. Además, se desarrolló e implementó un método para derivar una estrategia operativa óptima para el almacenamiento de electricidad. Esa estrategia tiene el objetivo de identificar un modo de operación autosuficiente que garantice el mayor beneficio posible y fue validada en una prueba en la región piloto. A pesar de ser la aplicación de baterías más lucrativa en Alemania hoy en día, los cálculos económicos han demostrado que el costo promedio de las baterías vanadio redox flow tendría que disminuir aproximadamente un 60% para lograr una operación rentable. No obstante, dado que esta es una nueva tecnología, tanto las expectativas como el potencial de reducción de costos son altos. La segunda aplicación más prometedora, la maximización del autoconsumo, también se analiza a través de una simulación para la región piloto, pero sin una implementación en el campo. Para este propósito, se aplica un modelo de batería vanadio redox flow basada en datos medidos del prototipo. Para garantizar el comportamiento de soporte de la red, se implementa un control de potencia reactiva autónomo basado en una característica Q (V) y una amortiguación de la generación máxima. La evaluación técnica y económica de esta estrategia de operación fue comparada con una batería de iones de litio que proporciona el mismo servicio. Fue demostrado que este caso comercial ya podría ser rentable, con un marco legal más favorable. Sin embargo, en la actualidad los costos de i baterías vanadio redox flow tienen que caer al menos en un 77% para obtener beneficios económicos. Sin embargo, se podía demostrar que los impactos económicos negativos son mínimos si la batería se opera en una forma de soporte de red además de su propósito principal. Finalmente, se llevó a cabo una evaluación técnica y económica del impacto de las dos aplicaciones de la batería a gran escala en la planificación de la red de distribución. Otras opciones de flexibilidad, como el control cos’φ (P) y Q (V) de los sistemas FV y el uso de baterías residenciales también fueron consideradas. Para este propósito, un escenario de expansión fotovoltaica para la región piloto fue desarrollado basado en la identificación de áreas de techo adecuadas para sistemas fotovoltaicos utilizando fotografías aéreas. Para cuantificar los costes para la expansión de la red eléctrica una metodología fue desarrollada para expandir la red de una forma automática y sistemática basado en directrices de planificación creados por los operadores del sistema de distribución en Alemania. Se demostró que desde la perspectiva de los operadores de red es más rentable aplicar la opción de flexibilidad presentada en lugar de una expansión de red tradicional.
Mühl, Gero. "Large-scale content based publish, subscribe systems." [S.l. : s.n.], 2002. http://elib.tu-darmstadt.de/diss/000274.
Full textParviainen, Roland. "Large scale and mobile group communication systems." Doctoral thesis, Luleå tekniska universitet, Datavetenskap, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-26688.
Full textGodkänd; 2005; 20061004 (ysko)
Al-Shishtawy, Ahmad. "Self-Management for Large-Scale Distributed Systems." Doctoral thesis, KTH, Programvaruteknik och Datorsystem, SCS, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101661.
Full textQC 20120831
Amadeo, Lily. "Large Scale Matrix Completion and Recommender Systems." Digital WPI, 2015. https://digitalcommons.wpi.edu/etd-theses/1021.
Full textGoldberg, David Alan Ph D. Massachusetts Institute of Technology. "Large scale queueing systems : asymptotics and insights." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67765.
Full textCataloged from PDF version of thesis.
Includes bibliographical references (p. 195-203).
Parallel server queues are a family of stochastic models useful in a variety of applications, including service systems and telecommunication networks. A particular application that has received considerable attention in recent years is the analysis of call centers. A feature common to these models is the notion of the 'trade-off' between quality and efficiency. It is known that if the underlying system parameters scale together according to a certain 'square-root scaling law', then this trade-off can be precisely quantified, in which case the queue is said to be in the Halfin-Whitt regime. A common approach to understanding this trade-off involves restricting one's models to have exponentially distributed call lengths, and restricting one's analysis to the steady-state behavior of the system. However, these are considered shortcomings of much work in the area. Although several recent works have moved beyond these assumptions, many open questions remain, especially w.r.t. the interplay between the transient and steady-state properties of the relevant models. These questions are the primary focus of this thesis. In the first part of this thesis, we prove several results about the rate of convergence to steady-state for the A/M/rn queue, i.e. n-server queue with exponentially distributed inter-arrival and processing times, in the Halfini-Whitt regime. We identify the limiting rate of convergence to steady-state, discover an asymptotic phase transition that occurs w.r.t. this rate, and prove explicit bounds on the distance to stationarity. The results of the first part of this thesis represent an important step towards understanding how to incorporate transient effects into the analysis of parallel server queues. In the second part of this thesis, we prove several results regarding the steadystate G/G/n queue, i.e. n-server queue with generally distributed inter-arrival and processing times, in the Halfin-Whitt regime. We first prove that under minor technical conditions, the steady-state number of jobs waiting in queue scales like the square root of the number of servers. We then establish bounds for the large deviations behavior of this model, partially resolving a conjecture made by Gamarnik and Momcilovic in [431. We also derive bounds for a related process studied by Reed in [91]. We then derive the first qualitative insights into the steady-state probability that an arriving job must wait for service in the Halfin-Whitt regime, for generally distributed processing times. We partially characterize the behavior of this probability when a certain excess parameter B approaches either 0 or oo. We conclude by studying the large deviations of the number of idle servers, proving that this random variable has a Gaussian-like tail. We prove our main results by combining tools from the theory of stochastic comparison [99] with the theory of heavy-traffic approximations [113]. We compare the system of interest to a 'modified' queue, in which all servers are kept busy at all times by adding artificial arrivals whenever a server would otherwise go idle, and certain servers can permanently break down. We then analyze the modified system using heavy-traffic approximations. The proven bounds hold for all n, have representations as the suprema of certain natural processes, and may prove useful in a variety of settings. The results of the second part of this thesis enhance our understanding of how parallel server queues behave in heavy traffic, when processing times are generally distributed.
by David Alan Goldberg.
Ph.D.
?ftar, Altu? "Robust controller design for large scale systems /." The Ohio State University, 1988. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487592050230031.
Full textWei, Chih-Ping 1965. "Schema management for large-scale multidatabase systems." Diss., The University of Arizona, 1996. http://hdl.handle.net/10150/290610.
Full textCaneill, Matthieu. "Contributions to large-scale data processing systems." Thesis, Université Grenoble Alpes (ComUE), 2018. http://www.theses.fr/2018GREAM006/document.
Full textThis thesis covers the topic of large-scale data processing systems,and more precisely three complementary approaches: the design of asystem to perform prediction about computer failures through theanalysis of monitoring data; the routing of data in a real-time systemlooking at correlations between message fields to favor locality; andfinally a novel framework to design data transformations usingdirected graphs of blocks.Through the lenses of the Smart Support Center project, we design ascalable architecture, to store time series reported by monitoringengines, which constantly check the health of computer systems. We usethis data to perform predictions, and detect potential problems beforethey arise.We then dive in routing algorithms for stream processing systems, anddevelop a layer to route messages more efficiently, by avoiding hopsbetween machines. For that purpose, we identify in real-time thecorrelations which appear in the fields of these messages, such ashashtags and their geolocation, for example in the case of tweets. Weuse these correlations to create routing tables which favor theco-location of actors handling these messages.Finally, we present λ-blocks, a novel programming framework to computedata processing jobs without writing code, but rather by creatinggraphs of blocks of code. The framework is fast, and comes withbatteries included: block libraries, plugins, and APIs to extendit. It is also able to manipulate computation graphs, foroptimization, analyzis, verification, or any other purposes
Stender, Jan. "Snapshots in large-scale distributed file systems." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2013. http://dx.doi.org/10.18452/16660.
Full textSnapshots are present in many modern file systems, where they allow to create consistent on-line backups, to roll back corruptions or inadvertent changes of files, and to keep a record of changes to files and directories. While most previous work on file system snapshots refers to local file systems, modern trends like cloud and cluster computing have shifted the focus towards distributed storage infrastructures. Such infrastructures often comprise large numbers of storage servers, which presents particular challenges in terms of scalability, availability and failure tolerance. This thesis describes snapshot algorithm for large-scale distributed file systems and its integration in XtreemFS, a scalable object-based file system for grid and cloud computing environments. The two building blocks of the algorithm are a version management scheme, which efficiently records versions of file content and metadata, as well as a scalable and failure-tolerant mechanism that aggregates specific versions in a snapshot. To overcome the lack of a global time in a distributed system, the algorithm implements a relaxed consistency model for snapshots, which is based on timestamps assigned by loosely synchronized server clocks. The main contributions of the thesis are: 1) a formal model of snapshots and snapshot consistency in distributed file systems; 2) the description of efficient schemes for the management of metadata and file content versions in object-based file systems; 3) the formal presentation of a scalable, fault-tolerant snapshot algorithm for large-scale object-based file systems; 4) a detailed description of the implementation of the algorithm as part of XtreemFS. An extensive evaluation shows that the proposed algorithm has no severe impact on user I/O, and that it scales to large numbers of snapshots and versions.
Famoso, Carlo. "Vibrational Control of Large Scale Electromechanical Systems." Doctoral thesis, Università di Catania, 2015. http://hdl.handle.net/10761/3860.
Full textAboucaya, William. "Collaborative systems for large scale citizen participation." Electronic Thesis or Diss., Sorbonne université, 2023. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2023SORUS461.pdf.
Full textOnline participatory platforms have become a common means to involve citizens in public decision-making, allowing for participation at a larger scale than their offline counterparts, both in the number of participants and in the geographical distribution. However, the term "participatory platform" covers a wide range of extremely different systems, implying differences in the problems encountered by platforms administrators and contributors. More precisely, such platforms face specific issues when they aim at allowing citizens to collaborate to produce common contributions or when the number of contributors involved becomes particularly high. This Ph.D. research aims at identifying issues in contemporary online citizen participation platforms and proposing technical means to create participatory platforms more collaborative and suitable for large scale online participation. My thesis is mainly based on previous works produced in the Computer-Supported Collaborative Work (CSCW) and Natural Language Processing (NLP) fields of computer science research. The contributions of this thesis are: the identification of flaws in a specific citizen participation platform and the recommendation of platform design-oriented alternatives to solve them; the representation of a participatory platform as a knowledge graph and its enrichment using a preexisting external knowledge base; the identification of the different objectives motivating the creation of participatory platforms and of the different types of features for interaction implemented based on a series of interviews; the conception and implementation of a Natural Language Inference-based method to reduce issues faced by online citizen participation when the number of contributors becomes particularly high
Pattnaik, Aliva. "Fault propagation analysis of large-scale, networked embedded systems." Thesis, Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42918.
Full textTong, Choon Yin. "Architecting the safety assessment of large-scale systems integration." Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FTong.pdf.
Full textThesis Advisor(s): Paulo, Eugene. Second Reader: Rhoades, Mark. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Systems integration, System safety, System-of-Systems safety. Includes bibliographical references (p. 51-52). Also available in print.
Janovsky, Pavel. "Large-scale coalition formation: application in power distribution systems." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35328.
Full textDepartment of Computing and Information Sciences
Scott A. DeLoach
Coalition formation is a key cooperative behavior of a system of multiple autonomous agents. When the capabilities of individual agents are not su fficient for the improvement of well-being of the individual agents or of the entire system, the agents can bene t by joining forces together in coalitions. Coalition formation is a technique for finding coalitions that are best fi tted to achieve individual or group goals. This is a computationally expensive task because often all combinations of agents have to be considered in order to find the best assignments of agents to coalitions. Previous research has therefore focused mainly on small-scale or otherwise restricted systems. In this thesis we study coalition formation in large-scale multi-agent systems. We propose an approach for coalition formation based on multi-agent simulation. This approach allows us to find coalitions in systems with thousands of agents. It also lets us modify behaviors of individual agents in order to better match a specific coalition formation application. Finally, our approach can consider both social welfare of the multi-agent system and well-being of individual self-interested agents. Power distribution systems are used to deliver electric energy from the transmission system to households. Because of the increased availability of distributed generation using renewable resources, push towards higher use of renewable energy, and increasing use of electric vehicles, the power distribution systems are undergoing signi ficant changes towards active consumers who participate in both supply and demand sides of the electricity market and the underlying power grid. In this thesis we address the ongoing change in power distribution systems by studying how the use of renewable energy can be increased with the help of coalition formation. We propose an approach that lets renewable generators, which face uncertainty in generation prediction, to form coalitions with energy stores, which on the other hand are always able to deliver the committed power. These coalitions help decrease the uncertainty of the power generation of renewable generators, consequently allowing the generators to increase their use of renewable energy while at the same time increasing their pro fits. Energy stores also bene t from participating in coalitions with renewable generators, because they receive payments from the generators for the availability of their power at speci fic time slots. We first study this problem assuming no physical constraints of the underlying power grid. Then we analyze how coalition formation of renewable generators and energy stores in a power grid with physical constraints impacts the state of the grid, and we propose agent behavior that leads to increase in use of renewable energy as well as maintains stability of the grid.
Bonis, Ioannis. "Optimisation and control methodologies for large-scale and multi-scale systems." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/optimisation-and-control-methodologies-for-largescale-and-multiscale-systems(6c4a4f13-ebae-4d9d-95b7-cca754968d47).html.
Full textGrass, Thomas. "Simulation methodologies for future large-scale parallel systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461198.
Full textDes dels principis dels anys 2000, els sistemes d'ordinadors han experimentat una transició de sistemes d'un sol nucli a sistemes de múltiples nuclis. Mentre els sistemes d'un sol nucli incloïen només un nucli en un xip, els sistemes actuals de múltiples nuclis n'inclouen desenes, una tendència que probablement continuarà en el futur. Avui en dia, els processadors de múltiples nuclis són omnipresents. Es fan servir en totes les classes de sistemes de computació, de telèfons mòbils de baix cost fins a sistemes de computació d'alt rendiment. Dissenyar els futurs sistemes de múltiples nuclis és un repte important. L'eina principal usada pels arquitectes de computadors, tant a l'acadèmia com a la indústria, és la simulació. Simular un ordinador executant un programa típicament és múltiples ordres de magnitud més lent que executar el mateix programa en un sistema real. Per tant, es necessiten noves tècniques per accelerar la simulació i permetre l'exploració de grans espais de disseny en un temps raonable. Una manera d'accelerar la velocitat de simulació és la simulació mostrejada. La simulació mostrejada redueix el temps de simulació simulant en detall només un subconjunt representatiu d¿un programa. En aquesta tesi es presenta una anàlisi de rendiment d'una col·lecció de programes basats en tasques. Com a resultat d'aquesta anàlisi, proposem TaskPoint, una metodologia de simulació mostrejada per programes basats en tasques. Els models de programació basats en tasques poden reduir els costos de sincronització de programes paral·lels executats en sistemes de múltiples nuclis i actualment estan guanyant importància. Finalment, presentem MUSA, una metodologia de simulació per simular aplicacions executant-se en milers de nuclis d'un sistema híbrid, que consisteix en nodes de memòria compartida que formen un sistema de memòria distribuïda. El temps que requereixen les simulacions amb MUSA és comparable amb el temps que triga l'execució nativa en un sistema d'alt rendiment en producció. Les tècniques desenvolupades al llarg d'aquesta tesi permeten simular execucions de programes que abans no eren viables, tant als investigadors com als enginyers que treballen en l'arquitectura de computadors. Per tant, aquest treball habilita futura recerca en el camp d'arquitectura de sistemes de memòria compartida o distribuïda, o bé de sistemes híbrids, a gran escala.
A principios de los años 2000, los sistemas de ordenadores experimentaron una transición de sistemas con un núcleo a sistemas con múltiples núcleos. Mientras los sistemas single-core incluían un sólo núcleo, los sistemas multi-core incluyen decenas de núcleos en el mismo chip, una tendencia que probablemente continuará en el futuro. Hoy en día, los procesadores multi-core son omnipresentes. Se utilizan en todas las clases de sistemas de computación, de teléfonos móviles de bajo coste hasta sistemas de alto rendimiento. Diseñar sistemas multi-core del futuro es un reto importante. La herramienta principal usada por arquitectos de computadores, tanto en la academia como en la industria, es la simulación. Simular un computador ejecutando un programa típicamente es múltiples ordenes de magnitud más lento que ejecutar el mismo programa en un sistema real. Por ese motivo se necesitan nuevas técnicas para acelerar la simulación y permitir la exploración de grandes espacios de diseño dentro de un tiempo razonable. Una manera de aumentar la velocidad de simulación es la simulación muestreada. La simulación muestreada reduce el tiempo de simulación simulando en detalle sólo un subconjunto representativo de la ejecución entera de un programa. En esta tesis presentamos un análisis de rendimiento de una colección de programas basados en tareas. Como resultado de este análisis presentamos TaskPoint, una metodología de simulación muestreada para programas basados en tareas. Los modelos de programación basados en tareas pueden reducir los costes de sincronización de programas paralelos ejecutados en sistemas multi-core y actualmente están ganando importancia. Finalmente, presentamos MUSA, una metodología para simular aplicaciones ejecutadas en miles de núcleos de un sistema híbrido, compuesto de nodos de memoria compartida que forman un sistema de memoria distribuida. El tiempo de simulación que requieren las simulaciones con MUSA es comparable con el tiempo necesario para la ejecución del programa simulado en un sistema de alto rendimiento en producción. Las técnicas desarolladas al largo de esta tesis permiten a los investigadores e ingenieros trabajando en la arquitectura de computadores simular ejecuciones largas, que antes no se podían simular. Nuestro trabajo facilita nuevos caminos de investigación en los campos de sistemas de memoria compartida o distribuida y en sistemas híbridos.
Leung, Andrew W. "Organizing, indexing and searching large-scale file systems /." Diss., Digital Dissertations Database. Restricted to UC campuses, 2009. http://uclibs.org/PID/11984.
Full textReimann, Carsten. "Model-Based Monitoring in Large-Scale Distributed Systems." Master's thesis, Universitätsbibliothek Chemnitz, 2002. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200200938.
Full textMonitoring ist ein wichtiges Problem in der Informatik. In dieser Arbeit werden die benoetigten Daten beschrieben, welche zur Analyse von verteilten Dienstumgebungen dienen. Weiterhin wird beschrieben, wie man diese Daten messen und in einer geeigneten Datenbank speichern kann. Das daraus entstehende Modell wird verwendet um eine verteilte Medien-Daten-Umgebung zu beschreiben und eine Simulation auf dem CLIC erzeugt Messdaten wie sie in realen Systemen vorkommen
Adam, Constantin. "A Middleware for Self-Managing Large-Scale Systems." Doctoral thesis, KTH, Skolan för elektro- och systemteknik (EES), 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4178.
Full textQC 20100629
Peng, Ivy Bo. "Data Movement on Emerging Large-Scale Parallel Systems." Doctoral thesis, KTH, Beräkningsvetenskap och beräkningsteknik (CST), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-218338.
Full textStorskaliga HPC-system är en viktig drivkraft för att lösa datorproblem i vetenskapliga samhällen. Nästa generations HPC-system kommer inte bara att växa i skala utan också i heterogenitet. Denna ökade systemkomplexitet medför flera utmaningar för dataförflyttning i HPC-applikationer. Dataförflyttning på nya HPC-system kräver asynkron, finkorrigerad kommunikation och en effektiv dataplacering i huvudminnet. Denna avhandling föreslår en innovativ programmeringsmodell och algoritm för att förbereda HPC-applikationer för nästa generation: (1) en dataströmningsmodell som stöder nya dataintensiva applikationer på superdatorer, (2) en kopplingsmodell som förbättrar parallelliteten och minskar obalans i applikationer, (3) en ny metologi och struktur för att förutse effekten av storskaliga, heterogena minnessystem på HPC-applikationer, och (4) en datalägesalgoritm som använder en uppsättning av regler och ett beslutsträd för att bestämma kartläggningen av data-till-minnet i det heterogena huvudminnet. Den föreslagna programmeringsmodellen i denna avhandling är utvärderad på flera superdatorer med olika processorer och sammankopplingsnät. Utvärderingen använder en mängd olika applikationer som representerar konventionella vetenskapliga applikationer och nya dataanalyser på HPC-system. Experimentella resultat på testbädden i petascala visar att programmeringsmodellen förbättrar prestandan när systemskalan ökar. Denna trend indikerar att modellen är ett värdefullt bidrag till framtida HPC-system.
QC 20171128
Bunce, Emma J. "Large-scale current systems in the Jovian magnetosphere." Thesis, University of Leicester, 2001. http://hdl.handle.net/2381/30647.
Full textAdam, Constantin M. "A middleware for self-managing large-scale systems /." Stockholm : School of Electrical Engineering (Institutionen för Elektrotekniska system), KTH, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4178.
Full textHendawy, Zeinab Mohamed. "Mathematical algorithms for optimisation of large scale systems." Thesis, City University London, 1989. http://openaccess.city.ac.uk/8248/.
Full textShepherd, Simon John. "A distributed security architecture for large scale systems." Thesis, University of Plymouth, 1992. http://hdl.handle.net/10026.1/2143.
Full textDialani, Vijay K. "Adaptive resource management in large scale distributed systems." Thesis, University of Southampton, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423041.
Full textAdly, Noha. "Management of replicated data in large scale systems." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.388345.
Full textPanneer, Selvan Vaina Malar. "Energy efficiency maximisation in large scale MIMO systems." Thesis, Brunel University, 2017. http://bura.brunel.ac.uk/handle/2438/16052.
Full textFavela, Jesus. "Organizational memory management for large-scale systems development." Thesis, Massachusetts Institute of Technology, 1993. http://hdl.handle.net/1721.1/12238.
Full textLiem, Rhea Patricia. "Surrogate modeling for large-scale black-box systems." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41559.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 105-110).
This research introduces a systematic method to reduce the complexity of large-scale blackbox systems for which the governing equations are unavailable. For such systems, surrogate models are critical for many applications, such as Monte Carlo simulations; however, existing surrogate modeling methods often are not applicable, particularly when the dimension of the input space is very high. In this research, we develop a systematic approach to represent the high-dimensional input space of a large-scale system by a smaller set of inputs. This collection of representatives is called a multi-agent collective, forming a surrogate model with which an inexpensive computation replaces the original complex task. The mathematical criteria used to derive the collective aim to avoid overlapping of characteristics between representatives, in order to achieve an effective surrogate model and avoid redundancies. The surrogate modeling method is demonstrated on a light inventory that contains light data corresponding to 82 aircraft types. Ten aircraft types are selected by the method to represent the full light inventory for the computation of fuel burn estimates, yielding an error between outputs from the surrogate and full models of just 2.08%. The ten representative aircraft types are selected by first aggregating similar aircraft types together into agents, and then selecting a representative aircraft type for each agent. In assessing the similarity between aircraft types, the characteristic of each aircraft type is determined from available light data instead of solving the fuel burn computation model, which makes the assessment procedure inexpensive.
(cont.) Aggregation criteria are specified to quantify the similarity between aircraft types and a stringency, which controls the tradeoff between the two competing objectives in the modeling -- the number of representatives and the estimation error. The surrogate modeling results are compared to a model obtained via manual aggregation; that is, the aggregation of aircraft types is done based on engineering judgment. The surrogate model derived using the systematic approach yields fewer representatives in the collective, yielding a surrogate model with lower computational cost, while achieving better accuracy. Further, the systematic approach eliminates the subjectivity that is inherent in the manual aggregation method. The surrogate model is also applied to other light inventories, yielding errors of similar magnitude to the case when the reference light inventory is considered.
by Rhea Patricia Liem.
S.M.
Zhang, Richard Yi. "Robust stability analysis for large-scale power systems." Thesis, Massachusetts Institute of Technology, 2017. http://hdl.handle.net/1721.1/108846.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Cataloged from student-submitted PDF version of thesis.
Includes bibliographical references (pages 145-154).
Innovations in electric power systems, such as renewable energy, demand-side participation, and electric vehicles, are all expected to increase variability and uncertainty, making stability verification more challenging. This thesis extends the technique of robust stability analysis to large-scale electric power systems under uncertainty. In the first part of this thesis, we examine the use of the technique to solve real problems faced by grid operators. We present two case studies: small-signal stability for distributed renewables on the IEEE 118-bus test system, and large-signal stability for a microgrid system. In each case study, we show that robust stability analysis can be used to compute stability margins for entire collections of uncertain scenarios. In the second part of this thesis, we develop scalable algorithms to solve robust stability analysis problems on large-scale power systems. We use preconditioned iterative methods to solve the Newton direction computation in the interior-point method, in order to avoid the O(n6) time complexity associated with a dense-matrix approach. The per-iteration costs of the iterative methods are reduced to O(n3) through a hierarchical block-diagonal-plus-low-rank structure in the data matrices. We provide evidence that the methods converge to an [epsilon]-accurate solution in O(1=[square root of ] [epsilon]) iterations, and characterize two broad classes of problems for which the enhanced convergence is guaranteed.
by Richard Yi Zhang.
Ph. D.
Rodriquez-Toral, Miguel Angel. "Synthesis and optimisation of large-scale utility systems." Thesis, University of Edinburgh, 1999. http://hdl.handle.net/1842/12878.
Full textHuynh, Phuong. "Stability analysis of large-scale power electronics systems." Diss., Virginia Tech, 1994. http://hdl.handle.net/10919/40205.
Full textPh. D.
Sakai, Kazuya. "Security and Privacy in Large-Scale RFID Systems." The Ohio State University, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=osu1386006971.
Full textBuccapatnam, Tirumala Swapna. "Control of Large Scale Networked Systems Under Uncertainty." The Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1416764356.
Full textHosny, Sameh Shawky Ibrahim. "LARGE SCALE LINEAR OPTIMIZATION FOR WIRELESS COMMUNICATION SYSTEMS." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1482232039296433.
Full textLi, Sen. "Transactive Control for Large-Scale Cyber-Physical Systems." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1511397616555155.
Full textZhao, Lin. "Aggregate Modeling of Large-Scale Cyber-Physical Systems." The Ohio State University, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=osu1512111263124549.
Full textQian, Chen. "Efficient cardinality counting for large-scale RFID systems /." View abstract or full-text, 2008. http://library.ust.hk/cgi/db/thesis.pl?CSED%202008%20QIAN.
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