Dissertations / Theses: 'Distributed'

1

Krysiak, Bruce R. (Bruce Robert). "Distributed tools for distributed thought : networked StarLogo." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36586.

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Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1995.
Includes bibliographical references (leaves 42-43).
by Bruce R. Krysiak.
M.Eng.

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2

Dixon, Eric Richard. "Developing distributed applications with distributed heterogenous databases." Thesis, Virginia Tech, 1993. http://hdl.handle.net/10919/42748.

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Hsu, Ing-Miin. "Distributed rule monitoring in distributed active databases /." The Ohio State University, 1993. http://rave.ohiolink.edu/etdc/view?acc_num=osu1487841975356679.

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4

Christakos, Constantine Kleomenis 1974. "Distributed-in/ distributed-out sensor networks : a new framework to analyze distributed phenomena." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/34183.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2006.
Includes bibliographical references (p. 155-165).
With a new way of thinking about organizing sensor networks, we demonstrate that we can more easily deploy and program these networks to solve a variety of different problems. We describe sensor networks that can analyze and actuate distributed phenomena without a central coordinator. Previous implementations of sensor networks have approached the problem from the perspective of centralized reporting of distributed events. By contrast, we create a system that allows users to infer the global state from within the sensor network itself, rather than by accessing an outside, central middleware layer. This is accomplished via dynamic creation of clusters of nodes based on application or intent, rather than proximity. The data collected and returned by these clusters is returned directly to the inquirer at his current location. By creating this Distributed-in/Distributed-out (DiDo) system that bypasses a middleware layer, our networks have the principal advantage of being easily configurable and deployable. We show that a system with this structure can solve path problems in a random graph. These graph problems are directly applicable to real-life applications such as discovering escape routes for people in a building with changing pathways. We show that the system is scalable, as reconfiguration requires only local communication.
(cont.) To test our assumptions, we build a suite of applications to create different deployment scenarios that model the physical world and set up simulations that allow us to measure performance. Finally, we create a set of simple primitives that serve as a high-level organizing protocol. These primitives can be used to solve different problems with distributed sensors, regardless of the underlying network protocols. The instructions provided by the sensors result in tangible performance improvements when the sensors' instructions are directed to agents within a simulated physical world.
by Constantine Kleomenis Christakos.
Ph.D.

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Wasif, Malik. "A Distributed Namespace for a Distributed File System." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-101482.

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Due to the rapid growth of data in recent years, distributed file systems have gained widespread adoption. The new breed of distributed file systems reliably store petabytes of data on commodity hardware, and also provide rich abstractions for massively parallel data analytics. The Hadoop Distributed File System (HDFS) is one such system which provides the storage layer for MapReduce, Hive, HBase and Mahout. The metadata server in HDFS, called the NameNode, is a centralized server which stores information about the whole namespace. The centralized architecture not only makes the NameNode a bottleneck and a single-point-of-failure, but also restricts the overall capacity of the filesystem. To solve the availability and scalability issues of HDFS, a new architecture is required. In this report, we propose a distributed implementation of the HDFS NameNode, where the filesystem metadata is stored in a distributed, in-memory, replicated database called MySQL Cluster. The NameNodes are state-less, and the throughput of the system can be increased by either adding NameNodes, or by adding more data nodes in NDB. HDFS clients can access the metadata by connecting to any one of the NameNodes. The evaluation section shows that the new architecture, as compared to HDFS, can handle more requests per second, store ten times more files and recover from failures within a few seconds.

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Bennett, John K. "Distributed Smalltalk : inheritance and reactiveness in distributed systems /." Thesis, Connect to this title online; UW restricted, 1988. http://hdl.handle.net/1773/6923.

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Calabrese, Chris M. Eng Massachusetts Institute of Technology. "Distributed inference : combining variational inference with distributed computing." Thesis, Massachusetts Institute of Technology, 2013. http://hdl.handle.net/1721.1/85407.

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Thesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2013.
Cataloged from PDF version of thesis.
Includes bibliographical references (pages 95-97).
The study of inference techniques and their use for solving complicated models has taken off in recent years, but as the models we attempt to solve become more complex, there is a worry that our inference techniques will be unable to produce results. Many problems are difficult to solve using current approaches because it takes too long for our implementations to converge on useful values. While coming up with more efficient inference algorithms may be the answer, we believe that an alternative approach to solving this complicated problem involves leveraging the computation power of multiple processors or machines with existing inference algorithms. This thesis describes the design and implementation of such a system by combining a variational inference implementation (Variational Message Passing) with a high-level distributed framework (Graphlab) and demonstrates that inference is performed faster on a few large graphical models when using this system.
by Chris Calabrese.
M. Eng.

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8

Norcross, Stuart John. "Deriving distributed garbage collectors from distributed termination algorithms." Thesis, University of St Andrews, 2004. http://hdl.handle.net/10023/14986.

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This thesis concentrates on the derivation of a modularised version of the DMOS distributed garbage collection algorithm and the implementation of this algorithm in a distributed computational environment. DMOS appears to exhibit a unique combination of attractive characteristics for a distributed garbage collector but the original algorithm is known to contain a bug and, previous to this work, lacks a satisfactory, understandable implementation. The relationship between distributed termination detection algorithms and distributed garbage collectors is central to this thesis. A modularised DMOS algorithm is developed using a previously published distributed garbage collector derivation methodology that centres on mapping centralised collection schemes to distributed termination detection algorithms. In examining the utility and suitability of the derivation methodology, a family of six distributed collectors is developed and an extension to the methodology is presented. The research work described in this thesis incorporates the definition and implementation of a distributed computational environment based on the ProcessBase language and a generic definition of a previously unimplemented distributed termination detection algorithm called Task Balancing. The role of distributed termination detection in the DMOS collection mechanisms is defined through a process of step-wise refinement. The implementation of the collector is achieved in two stages; the first stage defines the implementation of two distributed termination mappings with the Task Balancing algorithm; the second stage defines the DMOS collection mechanisms.

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9

Yeager, Philip S. "A distributed file system for distributed conferencing system." [Gainesville, Fla.] : University of Florida, 2003. http://purl.fcla.edu/fcla/etd/UFE0001123.

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Rieutord, Thibault. "Combinatorial characterization of asynchronous distributed computability." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLT007.

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Les systèmes informatiques modernes sont des systèmes distribués, allant de multiples processeurs sur une même puce à des systèmes internet de large échelle. Dans cette thèse nous étudions les problèmes de calculabilité et de complexité dans les systèmes distribués asynchrones communiquant par mémoire partagée.Dans la première et majeure partie de cette thèse, nous étudions la capacité des modèles communiquant par mémoire partagée à résoudre des tâches distribuées. Notre première contribution est une technique de simulation distribuée utilisant la capacité d’accord du système afin de synchroniser les différents processus entre eux. Cette technique de simulation permet de comparer la capacité de différents modèles à résoudre des tâches distribuées. À l’aide de cet outil, nous montrons que pour les modèles d’adversaires en mémoire partagée, la capacité à résoudre un ensemble particulier de tâches d’accord permet de déterminer sa capacité à résoudre n’importe quelle tâche distribuée. Nous utilisons ensuite les outils issus de la topologie combinatoire afin de caractériser la calculabilité des modèles par le biais de tâches affines: des complexes simpliciaux extraits d’itérations finies de la sous-division colorée standard. Cette caractérisation s’applique aux modèles dits sans-attente avec accès à des objets de “k-test-and-set” ainsi qu’à un large ensemble de modèles d’adversaires en mémoire partagée dits équitables. Ces résultats généralisent et améliorent toutes les caractérisations topologiques connues de la capacité à résoudre des tâches pour les modèles communiquant par mémoire partagée.Dans la seconde partie de la thèse, nous étudions la complexité spatiale de l’implémentation d’un stockage fiable, c.à.d., assurant qu’une valeur écrite en mémoire est persistante, dans le modèle à base de comparaison où seuls les identifiants peuvent être comparés. Nos résultats montrent l’existence d’un compromis non-trivial entre la complexité spatiale d’une implémentation et les garanties de vivacité qu’elle apporte
Modern computing systems are distributed, ranging from single-chip multi-processors to large-scale internet systems. In this thesis, we study computability and complexity issues raising in asynchronous crash-prone shared memory systems.The major part of this thesis is devoted to characterizing the power of a shared memory model to solve distributed tasks. Our first contribution is a refined and extended agreement-based simulation technique that allows us to reason about the relative task computability of shared-memory models. Using this simulation technique, we show that the task computability of a shared-memory adversarial model is grasped by its ability to solve specific agreement tasks. We then use the language of combinatorial topology to characterize the task computability of shared-memory models via affine tasks: sub-complexes of a finite iteration of the standard chromatic subdivision. Our characterization applies to the wait-free model enhanced with k-test-and-set objects and a to large class of fair adversarial models. These results generalize and improve all previously derived topological characterizations of the task computability power of shared memory models.In the second part of the thesis, we focus on space complexity of implementing stable storage, i.e., ensuring that written values persists in memory, in the comparison-based model using multi-writer registers. Our results exhibit a non-trivial tradeoff between space complexity of stable-storage implementations and the progress guarantees they provide

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11

Trommer, Jochen. "Distributed optimality." Phd thesis, [S.l. : s.n.], 2001. http://pub.ub.uni-potsdam.de/2004/0037/trommer.pdf.

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12

Lindström, Robin, and Tobias Rosvall. "Distributed propulsion." Thesis, KTH, Farkost och flyg, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-140941.

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En prestandaanalys utfördes på en SAAB 2000 som referensobjekt. Olika metoder för att driva flygplan på ett miljövänligare sätt utvärderades tillsammans med distributed propulsion. Efter undersökningar valdes elmotorer tillsammans med Zink-luft batterier för att driva SAAB 2000 med distributed propulsion. En prestandaanalys utfördes på detta plan på samma sätt som för den ursprungliga SAAB 2000. Resultaten jämfördes och slutsatsen blev att räckvidden var för kort för att konfigurationen skulle hålla i verkligheten. Detta berodde på den dåliga kapaciteten hos batterierna. Många fördelar hittades med elmotorer bl.a. deras låga ljudnivå och deras höga effektivitet. Men problemet är systemet som förser dessa med ström.

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13

Duerr, Erik Kurt 1973. "Distributed photomixers." Thesis, Massachusetts Institute of Technology, 2002. http://hdl.handle.net/1721.1/16895.

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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2002.
Includes bibliographical references (p. 187-197).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Although the terahertz domain has been explored scientifically, components, especially sources, are needed to enable further exploration of the frequency range. A photomixer generates coherent THz radiation through optical heterodyne down-conversion. A terahertz-frequency beat signal on an optical carrier illuminates an ultrafast photoconductor, modulating the conductance. The time-varying conductance together with a constant voltage bias generates time-varying current at the beat frequency. Low-temperature-grown gallium arsenide (LTG-GaAs) is the photoconductive material of choice, because its short carrier lifetime allows the conductance to be efficiently modulated at THz frequencies. The distributed photomixer described in this thesis is a new style of LTG-GaAs photomixer which uses an optical waveguide to couple the beat signal to an active area whichis large relative to the terahertz wavelength. This large, traveling-wave mode active area distributes the heat load from absorbed optical power and ohmic heating from photocurrent and avoids the RC rolloff associated with a lumped-element photomixer's intrinsic capacitance and the load resistance. The distributed photomixer structure consists of coplanar strips (CPS) fabricated on top of a dielectric strip-loaded waveguide that guides the optical beat.
(cont.) The conductance of a thin layer of LTG-GaAs between the CPS and optical guide is modulated by the weakly coupled optical signal. The THz conductance wave between the dc-biased CPS creates a THz electromagnetic wave which propagates along the CPS. To velocity match the THz and optical waves, the CPS are periodically loaded with thin electrodes that add a small shunt capacitance to the line. The CPS are terminated in a planar antenna that radiates the THz wave. This thesis describes the design, fabrication, and testing of waveguide-coupled distributed photomixers. The photomixers demonstrated in this thesis operated in travelingwave mode and produced 100 nW of power at 0.3 THz and the power output rolled off at 6 dB/octave until 1.4 THz. A model which qualitatively and quantitatively predicts the device performance as a function of frequency, illumination and voltage bias is developed. A general design methodology, detailed discussion of fabrication steps and possible methods to increase output power are also presented.
by Erik Kurt Duerr.
Ph.D.

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14

Collins, Andrew. "Distributed navigation." Thesis, University of Liverpool, 2013. http://livrepository.liverpool.ac.uk/12415/.

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In this thesis, a number of problems are looked at predominately in the area of mobile agent communication protocols. Particularly, with the recent uptake of unstructured, large and dynamic networks there is a demand for cheap, ubiquitous and reliable protocols that will assist in the support of the network through tasks such as information dissemination, information search and retrieval, and network monitoring. One of the exciting new possible solutions to this is in the area of mobile agents where by a team of dedicated agents (physical or purely virtual) act independently or within a team on the network in the goal of solving simple, yet highly valuable, tasks. Independent agents may work within the bounds of their environment and without influence from their colleagues to solve simple or potentially complex tasks. Further, the agents may also act independently but in actuality work as a very complex team with simple underlying principles allowing for large scale networks and problems to be handled autonomously. In this work, two problems are investigated in detail, the Rendezvous Problem and Network Patrolling. In the rendezvous problem, the goal is to identify algorithms that will permit two agents to rendezvous within some known or unknown environment. This problem, while at first can feel trivial, it can be incredibly difficult when it is realised that all agents are expected to be identical at wake-up time, and that methods must be found that allow for the breaking of symmetry. This thesis provides an investigation into a number of models and environments and tries to provide optimal algorithms for allow rendezvous to occur. Secondly in the area of network patrolling, this work investigates the problem where there exists an environment, in which parts of it are viewed as being vital to network integrity and as such must be monitored. When there are less agents than vital regions the challenge of identifying traversal routes that minimise idle time becomes apparent. In this work an algorithm is presented that minimises this in the ring environment. Finally, this work also looks at other problems in distributed computing and provides exploratory foundation work that could provide alternative models for routing problems, distributed processing, community identification, and presents a number of open problems.

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15

Martimiano, Taciane. "Distributed attacker." reponame:Repositório Institucional da UFSC, 2017. https://repositorio.ufsc.br/xmlui/handle/123456789/176799.

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Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Ciência da Computação, Florianópolis, 2017
Made available in DSpace on 2017-06-27T04:22:41Z (GMT). No. of bitstreams: 1 345978.pdf: 978430 bytes, checksum: e7dbdcc1dd284e84bcac339aae3f6488 (MD5) Previous issue date: 2017
Abstract : Security ceremonies are extensions of security protocols, including all that is out-of-bounds for protocols. Nowadays we lack a base description language and a detailed threat model for security ceremonies in order to be able to use symbolic evaluation methods and verify claims embedded in ceremonies. Our goal is to contribute with a syntax and detailed threat model for ceremonies description in order to establish our proposal for a new attacker type named Distributed Attacker (DA in brief). Moreover, we also developed a strategy for symbolic evaluation of our attacker model using First-Order Logic (FOL) and an automatic theorem prover. Lastly, we present scenarios formally analysed with our methodology, including cases we could not have with standard Dolev-Yao or Multi-Attacker models. For instance, our most interesting scenario is when several attackers gather only pieces of an user's credentials and, by putting together their knowledge, collude to attack this user's email account.

Protocolos de segurança são subconjuntos das chamadas cerimônias de segurança. Atualmente não se tem uma linguagem de descrição e um modelo de ameaça detalhado para cerimônias de segurança, necessários para o uso de métodos de avaliação simbólica e verificação de suposições presentes em cerimônias. O objetivo desta dissertação é contribuir com uma sintaxe para descrição de mensagens de cerimônias e apropriado modelo de ameaça a fim de estabelecer a proposta para um novo tipo de atacante (nomeado Atacante Distribuído). Adicionalmente, uma estratégia para execução de avaliação simbólica também foi desenvolvida, utilizando lógica de primeira ordem e um provador de teoremas automático. Por fim, cenários formalmente analisados com o modelo de atacante proposto são exibidos, incluindo casos não passíveis de serem simulados com modelos padrão como Dolev-Yao ou Multi-Attacker. Por exemplo, o caso mais interessante é o que apresenta vários atacantes com conhecimento apenas de partes das credenciais de um usuário, mas que ao colaborar entre si conseguem atacar a conta de email desse usuário.

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16

Ghodsi, Ali. "Distributed k-ary System: Algorithms for Distributed Hash Tables." Doctoral thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4186.

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This dissertation presents algorithms for data structures called distributed hash tables (DHT) or structured overlay networks, which are used to build scalable self-managing distributed systems. The provided algorithms guarantee lookup consistency in the presence of dynamism: they guarantee consistent lookup results in the presence of nodes joining and leaving. Similarly, the algorithms guarantee that routing never fails while nodes join and leave. Previous algorithms for lookup consistency either suffer from starvation, do not work in the presence of failures, or lack proof of correctness. Several group communication algorithms for structured overlay networks are presented. We provide an overlay broadcast algorithm, which unlike previous algorithms avoids redundant messages, reaching all nodes in O(log n) time, while using O(n) messages, where n is the number of nodes in the system. The broadcast algorithm is used to build overlay multicast. We introduce bulk operation, which enables a node to efficiently make multiple lookups or send a message to all nodes in a specified set of identifiers. The algorithm ensures that all specified nodes are reached in O(log n) time, sending maximum O(log n) messages per node, regardless of the input size of the bulk operation. Moreover, the algorithm avoids sending redundant messages. Previous approaches required multiple lookups, which consume more messages and can render the initiator a bottleneck. Our algorithms are used in DHT-based storage systems, where nodes can do thousands of lookups to fetch large files. We use the bulk operation algorithm to construct a pseudo-reliable broadcast algorithm. Bulk operations can also be used to implement efficient range queries. Finally, we describe a novel way to place replicas in a DHT, called symmetric replication, that enables parallel recursive lookups. Parallel lookups are known to reduce latencies. However, costly iterative lookups have previously been used to do parallel lookups. Moreover, joins or leaves only require exchanging O(1) messages, while other schemes require at least log(f) messages for a replication degree of f. The algorithms have been implemented in a middleware called the Distributed k-ary System (DKS), which is briefly described.
QC 20100824

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17

Farooqui, Kazi. "Group-based distributed computing: Programming and distributed platform model." Thesis, University of Ottawa (Canada), 2000. http://hdl.handle.net/10393/8518.

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Much research has been done in the past in the area of group communication. However most of this research exists in the low-level support for group communication, such as different types of ordered and reliable multicast protocols, membership management protocols, virtual synchrony, replication techniques, etc. Most of this research provides only low-level pieces of the complete puzzle. The big picture involves a vision of group-based distributed computing . This vision calls for a shift of focus from low-level issues of group communication to the high-level issues of an overall distributed environment capable of supporting group-based distributed computing applications . This thesis is focussed on the dual models of the distributed environment---the distributed programming model and the distributed platform model, required for the support of group-based distributed computing applications. The thesis presents the software architecture of an agent-based and policy-driven group support platform in an implementation independent manner. This is an extensible, configurable and programmable software architecture which permits the separation of group coordination aspects from the application issues. The goal is to enhance the level of middleware support provided by the current generation of distributed platforms such as CORBA. The thesis identifies a set of "middleware-level" group support services (GSSs), such as message distribution service, collation service, synchronisation service, filtering service, etc. commonly required by group-based applications and the corresponding group support agents (GSAs). The thesis presents a framework for the organisation of these group support agents. This framework is called the group support machine (GSM). This thesis is based upon the architectural principles underlying object-based distributed systems architectures such as RM-ODP, ANSA, ROSA, OMA, etc., and is scoped within the ODP computational and engineering models. (Abstract shortened by UMI.)

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Farooqui, Kazi. "Group-based distributed computing, programming & distributed platform model." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2000. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape3/PQDD_0015/NQ57039.pdf.

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19

Mendoza, Hermie P. "Distributed Localization for Wireless Distributed Networks in Indoor Environments." Thesis, Virginia Tech, 2011. http://hdl.handle.net/10919/33805.

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Positioning systems enable location-awareness for mobile devices, computers, and even tactical radios. From the collected location information, location-based services can be realized. One type of positioning system is based on location fingerprints. Unlike the conventional positioning techniques of time of or time delay of arrival (TOA/TDOA) or even angle of arrival (AOA), fingerprinting associates unique characteristics such as received signal strength (RSS) that differentiates a location from another location. The location-dependent characteristics then can be used to infer a userâ s location. Furthermore, fingerprinting requires no specialized hardware because of its reliance on an existing communications infrastructure. In estimating a userâ s position, fingerprint-based positioning systems are centrally calculated on a mobile computer using either a Euclidean distance algorithm, Bayesian statistics, or neural networks. With large service areas and, subsequently, large radio maps, one mobile computer may not have the adequate resources to locally compute a userâ s position. Wireless distributed computing provides a means for the mobile computer to meet the location-based service requirements and increase its network lifetime. This thesis develops distributed localization algorithms to be used in an indoor fingerprint-based positioning system. Fingerprint calculations are not computed on a single device, but rather on a wireless distributed computing network on Virginia Techâ s Cognitive Radio Network Testbed (CORNET).
Master of Science

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Lundin, Mats. "Building Distributed Control Systems Using Distributed Active Real-Time Databases." Thesis, University of Skövde, Department of Computer Science, 1998. http://urn.kb.se/resolve?urn=urn:nbn:se:his:diva-234.

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From the field of control theory, we can see that varying communication delays in a control system may be hard or even impossible to handle. From this point of view it is preferable to have these delays bounded and as small and as possible in order to adapt the control process to them. On the other hand, in some cases delays are inevitable and must be handled by the control system.

A control system may for different reasons be distributed, e.g., because of a distributed environment or severe environment demands such as heat or dust at some locations. Information in such a system will suffer from delays due to transportation from one place to another. These delays often show up in a random fashion, especially if a general network is used for transportation. Another source of delays is the system environment itself. For predictability reasons a real-time database is preferable if the delays are to be controlled.

A straightforward way of handling delays in a control system is to build the system such that delays are constant, i.e., to build a time invariant system. The time from sensor reading to actuation is made constant either by adding a suitable delay to achieve a total constant delay or by using time-triggered reading and actuation. These are simple ways of controlling the delays, but may be very inefficient because worst-case execution time must always be used. Other ways of handling varying delays are by using more tolerant control algorithms. There are two suitable control models proposed by Nilsson (1998) for this purpose. The tolerant algorithm approach is assumed in this work.

This thesis uses a distributed active real-time database system as a basis for building control systems. One of the main objectives is to determine how active functionality can be used to express the control system, i.e., how rules in the database can be used to express the control algorithm and for handling propagation of information. Another objective is to look at how the choice of consistency level in the database affects the result of the control system, i.e. how different consistency level affects the delays. Of interest is also to characterize what type of applications each level is suited for.

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Oztas, Gokhan. "Testing Distributed Real-time Systems With A Distributed Test Approach." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609492/index.pdf.

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Software testing is an important phase the of software development cycle which reveals faults and ensures correctness of the developed software. Distributed real-time systems are mostly safety critical systems for which the correctness and quality of the software is much more significant. However, majority of the current testing techniques have been developed for sequential (non real-time) software and there is a limited amount of research on testing distributed real-time systems. In this thesis, a proposed approach in the academic literature testing distributed real-time systems using a distributed test architecture is implemented and compared to existing software testing practices in a software development company on a case study. Evaluation of the results show the benefits of using the considered distributed test approach on distributed real-time systems in terms of software correctness.

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Cons, Bacilla Ferreira Daniel Gebbran. "Coordination of Distributed Energy Resources using Distributed Optimal Power Flow." Thesis, The University of Sydney, 2021. https://hdl.handle.net/2123/26155.

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Electrical power systems are deemed as one of the most complex systems mankind has built to date. Nonetheless, continuous changes on electricity generation and consumption are increasing the complexity of these systems. The uptake of behind-the-meter distributed energy resources (DER) (such as rooftop PV, battery systems, and flexible loads) requires a more precise coordination of all agents in the grid. This is particularly true for distribution systems, which are traditionally passive systems but require coordination under a high percentage of DER penetration. To perform such coordination, the centralized power system operation paradigm becomes incapable of handling the necessary information flow and computation burden required. Distributed coordination methods offer an alternative to this paradigm. In particular, distributed AC optimal power flow (DOPF) solved using a prosumer-based decomposition emerge as an effective tool for three main reasons: (i) they explicitly consider network constraints in their formulation, (ii) they permit a prosumer-based decomposition, which retains prosumer privacy and prerogative, and (iii) they computationally scalable. Distributed methods are further bolstered by the advances on technology systems towards an IoT, edge-computing scenario. The miniaturization of sensors and computing devices, and reliable and efficient telecommunication technologies, allow for deployment of coordination methods with progressively smaller investments. The present dissertation expands the frontiers of DER coordination, offering advances on both implementation aspects by presenting practical considerations on actual distributed, edge-computing hardware, as well as developing novel formulations for more advanced problems which assume realistic design considerations, a key to implementing DER coordination in real-world settings.

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Benelallam, Amine. "Model transformation on distributed platforms : decentralized persistence and distributed processing." Thesis, Nantes, Ecole des Mines, 2016. http://www.theses.fr/2016EMNA0288/document.

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Grâce à sa promesse de réduire les efforts de développement et maintenance du logiciel, l’Ingénierie Dirigée par les Modèles (IDM) attire de plus en plus les acteurs industriels. En effet, elle a été adoptée avec succès dans plusieurs domaines tels que le génie civil, l’industrie automobile et la modernisation de logiciels.Toutefois, la taille croissante des modèles utilisés nécessite de concevoir des solutions passant à l’échelle afin de les traiter (transformer), et stocker (persister) de manière efficace. Une façon de pallier cette problématique est d’utiliser les systèmes et les bases de données répartis. D’une part, les paradigmes de programmation distribuée tels que MapReduce et Pregel peuvent simplifier la distribution de transformations des modèles (TM). Et d’autre part, l’avènement des base de données NoSQL permet le stockage efficace des modèles d’une manière distribuée. Dans le cadre de cette thèse, nous proposons une approche pour la transformation ainsi que pour la persistance de grands modèles.Nous nous basons d’un côté, sur le haut niveau d’abstraction fourni par les langages déclaratifs (relationnels) de transformation et d’un autre côté, sur la sémantique bien définie des paradigmes existants de programmation distribués, afin de livrer un moteur distribué de TM. La distribution est implicite et la syntaxe du langage n’est pas modifiée (aucune primitive de parallélisation n’est ajoutée). Nous étendons cette solution avec un algorithme efficace de distribution de modèles qui se base sur l’analyse statique des transformations et sur résultats récents sur le partitionnement équilibré des graphes. Nous avons appliqué notre approche à ATL, un langage relationnel de TM et MapReduce, un paradigme de programmation distribué. Finalement, nous proposons une solution pour stocker des modèles à l’aide de bases de données NoSQL, en particulier au travers d’un cadre d’applications de persistance répartie
Model-Driven Engineering (MDE) is gaining ground in industrial environments, thanks to its promise of lowering software development and maintenance effort. It has been adopted with success in producing software for several domains like civil engineering, car manufacturing and modernization of legacy software systems. As the models that need to be handled in model-driven engineering grow in scale, it became necessary to design scalable algorithms for model transformation (MT) as well as well-suitable persistence frameworks. One way to cope with these issues is to exploit the wide availability of distributed clusters in the Cloud for the distributed execution of model transformations and their persistence. On one hand, programming models such as MapReduce and Pregel may simplify the development of distributed model transformations. On the other hand, the availability of different categories of NoSQL databases may help to store efficiently the models. However, because of the dense interconnectivity of models and the complexity of transformation logics, scalability in distributed model processing is challenging. In this thesis, we propose our approach for scalable model transformation and persistence. We exploit the high-level of abstraction of relational MT languages and the well-defined semantics of existing distributed programming models to provide a relational model transformation engine with implicit distributed execution. The syntax of the MT language is not modified and no primitive for distribution is added. Hence developers are not required to have any acquaintance with distributed programming.We extend this approach with an efficient model distribution algorithm, based on the analysis of relational model transformation and recent results on balanced partitioning of streaming graphs. We applied our approach to a popular MT language, ATL, on top of a well-known distributed programming model, MapReduce. Finally, we propose a multi-persistence backend for manipulating and storing models in NoSQL databases according to the modeling scenario. Especially, we focus on decentralized model persistence for distributed model transformations

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Volpe, Alessio. "Virtual Distributed Container." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16748/.

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Nell'ambito che vede protagonisti i container per la realizzazione di applicazioni distribuite Virtual Distributed Container (VDC) offre un nuovo modello di rete. Questo lavoro ha l'obiettivo di fornire il supporto delle reti VDE ai container Docker. VDC è implementato sotto forma di plugin installabile all'interno di Docker.

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Meesangphrao, Ukrit. "Distributed Underwater Sonar." Thesis, Mälardalens högskola, Akademin för innovation, design och teknik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:mdh:diva-13230.

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This thesis is focused on possibility of constructing distributed underwater sonar which has an ability to increase or decrease number of sensor elements without any modification on its hardware. Each sonar module works individually. Its synchronization and communication between modules and the image processing unit are archived by using CAN protocol. This new design concept gives several advantages over conventional design.Only one prototype was made, but several modules must be combined in the actual application. The discussion about a complete system can be found in the future work section.The project composes of two main parts: design and building a prototype. The testing procedure and result of both parts are described and summarized with a conclusion.

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Sterne, Philip Jonathan. "Distributed associative memory." Thesis, University of Cambridge, 2011. https://www.repository.cam.ac.uk/handle/1810/265517.

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This dissertation modifies error-correcting codes and Bloom filters to create high-capacity associative memories. These associative memories use principled statistical inference and are distributed as no single component contains enough information to complete the task by itself, yet the components can collectively solve the task by passing information to each other. These associative memories are also robust to hardware failure as their distributed nature ensures there is no single point of failure. This dissertation starts by simplifying a Bloom filter so that it tolerates hardware failure (albeit with reduced performance). An efficient associative memory is created by performing inference over the set of items stored in the Bloom filter. This architecture suggests a modification which forgets old patterns stored in the associative memory (known as a palimpsest memory). It is shown that overwriting old patterns in an independent manner reduces performance, but is still comparable to the well-known Hopfield network. The lost performance can be regained using integer storage which allows the superposition of the pattern representation, or ensuring bits are not overwritten independently using concepts from errorcorrecting codes. The final task performs recall in continuous time using components which are more similar to neurons than used in the rest of the dissertation. The resulting memory has the exciting ability to recall many patterns simultaneously. Statistical inference ensures gradual degradation of the performance as an associative memory is overloaded. Since many definitions of associative memory capacity rely on the existence of catastrophic failure a new definition of capacity is provided. In spite of some biologically unrealistic attributes, this work is relevant to the understanding of the brain as it provides high performance solutions to the associative memory task which is known to be relevant to the brain.

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Kent, Eamonn. "Distributed fault location." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1998. http://www.collectionscanada.ca/obj/s4/f2/dsk2/ftp01/MQ30715.pdf.

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Nemlekar, Milind. "SCALABLE DISTRIBUTED TUPLESPACES." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20011130-173537.

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NEMLEKAR, MILIND NILKANTH. Scalable Distributed Tuplespaces. (Under the direction of Dr. Gregory T. Byrd.)

The purpose of the research has been to develop a multiple tuplespace model that would scale as much as the Internet. A tuplespace is like a shared cache, in which tuples are accessed associatively. One issue in designing a multiple tuplespaces model is keeping track of tuples over multiple space servers. Since, replication is used to reduce access latencies to tuples, another issue is of establishing coherency of replicas and consistency of tuplespace operations over multiple replicas.

The thesis looks at design of a hierarchical directory structure over a flat organization of tuplespaces, which addresses the above issues. With this model scalable protocols are proposed that keep track of tuples/templates among multiple nodes, and establish coherency of tuple replicas.

A prototype of this model has been implemented within the Jini

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Albrecht, Jeannie Raye. "Distributed application management." Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2007. http://wwwlib.umi.com/cr/ucsd/fullcit?p3258704.

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Thesis (Ph. D.)--University of California, San Diego, 2007.
Title from first page of PDF file (viewed June 4, 2007). Available via ProQuest Digital Dissertations. Vita. Includes bibliographical references (p. 144-153).

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Yildiz, Beytullah. "Distributed handler architecture." [Bloomington, Ind.] : Indiana University, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3277972.

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Thesis (Ph.D.)--Indiana University, Dept. of Computer Science, 2007.
Source: Dissertation Abstracts International, Volume: 68-09, Section: B, page: 6098. Adviser: Geoffrey C. Fox. Title from dissertation home page (viewed May 9, 2008).

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Yu, Xiaoning. "Distributed interactive simulation." Thesis, Brunel University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310078.

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Rawlings, Trevor. "Distributed control architecture." Thesis, Loughborough University, 2009. https://dspace.lboro.ac.uk/2134/6077.

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This document describes the development and testing of a novel Distributed Control Architecture (DCA). The DCA developed during the study is an attempt to turn the components used to construct unmanned vehicles into a network of intelligent devices, connected using standard networking protocols. The architecture exists at both a hardware and software level and provides a communication channel between control modules, actuators and sensors. A single unified mechanism for connecting sensors and actuators to the control software will reduce the technical knowledge required by platform integrators and allow control systems to be rapidly constructed in a Plug and Play manner. DCA uses standard networking hardware to connect components, removing the need for custom communication channels between individual sensors and actuators. The use of a common architecture for the communication between components should make it easier for software to dynamically determine the vehicle s current capabilities and increase the range of processing platforms that can be utilised. Implementations of the architecture currently exist for Microsoft Windows, Windows Mobile 5, Linux and Microchip dsPIC30 microcontrollers. Conceptually, DCA exposes the functionality of each networked device as objects with interfaces and associated methods. Allowing each object to expose multiple interfaces allows for future upgrades without breaking existing code. In addition, the use of common interfaces should help facilitate component reuse, unit testing and make it easier to write generic reusable software.

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Verwoerd, Theuns Willem. "Stateful distributed firewalls." Thesis, University of Canterbury. Computer Science and Software Engineering, 2001. http://hdl.handle.net/10092/9620.

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A fundamental feature in current network security architectures is the monolithic firewall. This thesis presents an alternative design, consisting of a cluster of small firewall nodes, that offers better economy, scalability, failure recovery and potentially, greatly increased processing power. These improvements allow the use of computationally expensive firewalling and IDS techniques to offer effective protection against all types of network attack. Also presented are techniques for developing fault-tolerant proxy applications, maintaining connections in spite of node failures, and a novel load balancing design. Generic Load Balancing (GLOB) uses per-node filtering to distribute network load transparently in a cluster without any single points of failure. This thesis also presents evaluations of prototype implementations of these techniques

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Buss, John, Rico Magbanua, Chrisman Thompson, Wei Quan Toh, Min Yan Tan, John Goff, Andrew Moss, et al. "Distributed surface force." Thesis, Monterey, California: Naval Postgraduate School, 2014. http://hdl.handle.net/10945/42716.

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Approved for public release; distribution is unlimited
Large naval surface combatants are potentially held at risk by adversarial anti-access aerial denial (A2AD) weapon systems. To mitigate that risk we propose a distributed surface force concept, which relies on a cost-effective small surface combatant (SSC) capable of augmenting current forces in the 2025–2030 timeframe. We show that dispensing offensive and defensive power onto numerous smaller platforms has several advantages, including a more resilient force structure, greater number of ships, and fiscal cost savings. After employing the systems engineering process tailored to the problem to understand requirements and alternatives, a single mission SSC adapted to anti-surface warfare (ASUW) emerged as the solution. The SSC is conceptually employed in an armada composed of existing naval forces, which provide a protective shield against a multi-threat enemy force. The Armada is nominally composed of Arleigh Burke-class destroyers, Littoral Combat Ships and SSCs. The SSC’As capabilities include eight anti-ship cruise missiles with a range of 90 nautical miles, speed greater than 25 knots, and organic detection and classification range of at least 60 nautical miles.

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Thompson, Simon Giles. "Distributed boosting algorithms." Thesis, University of Portsmouth, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285529.

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Kindberg, Timothy Paul James Gerard. "Reconfiguring distributed computations." Thesis, University of Westminster, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.304866.

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Perez, Hector Benitez. "Smart distributed systems." Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310944.

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Kunarajah, Enoch Arumaishanth. "Distributed Raman amplifiers." Thesis, University of Essex, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.399979.

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Prosser, Patrick. "Distributed asynchronous scheduling." Thesis, University of Strathclyde, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296921.

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Lee, Li 1975. "Distributed signal processing." Thesis, Massachusetts Institute of Technology, 2000. http://hdl.handle.net/1721.1/86436.

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Brittain, Eric A. (Eric Audwoyne) 1972. "Distributed visibility servers." Thesis, Massachusetts Institute of Technology, 2001. http://hdl.handle.net/1721.1/8948.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2001.
Includes bibliographical references (leaves 54-55).
This thesis describes techniques for computing conservative visibility exploiting viewpoint prediction, spatial coherence and remote visibility servers to increase the rendering performance of a walk through client. Identifying visible (or partially visible) geometry from an instantaneous viewpoint of a 3-D computer graphics model in real-time is an important problem in interactive computer graphics. Since rendering is an expensive process (due to transformations, lighting and scan-conversion), successfully identifying the exact set of visible geometry before rendering increases the frame-rate of real-time applications. However, computing this exact set is computationally intensive and prohibitive in real-time for large models. For many densely occluded environments that contain a small number of large occluding objects (such as buildings, billboards and houses), efficient conservative visibility algorithms have been developed to identify a set of occluded objects in real-time. These algorithms are conservative since they do not identify the exact set of occluded geometry. While visibility algorithms that identify occluded geometry are useful in increasing the frame-rate of interactive applications, previous techniques have not attempted to utilize a set of workstations connected via a local area network as an external compute resource. We demonstrated a configuration with one local viewer and two remote servers.
by Eric A. Brittain.
S.M.

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Williams, Greg Jeffrey. "Molecular distributed polarisabilities." Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614775.

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Hošek, Václav. "Distributed Ray Tracing." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2008. http://www.nusl.cz/ntk/nusl-235956.

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VYSOKÉ UČENÍ TECHNICKÉ V BRNĚ Distributed Ray Tracing, also called distribution ray tracing and stochastic ray tracing, is a refinement of ray tracing that allows for the rendering of "soft" phenomena, area light, depth of field and motion blur.

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Loganathan, Satish Kumar. "Distributed Hierarchical Clustering." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1544001912266574.

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Iyer, Ranjit. "Probabilistic distributed control." Diss., Restricted to subscribing institutions, 2008. http://proquest.umi.com/pqdweb?did=1568128211&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

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Jew, Yanni K. Carleton University Dissertation Computer Science. "Distributed garbage collection." Ottawa, 1986.

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McAffer, Jeff (Jeffrey Alan) Carleton University Dissertation Computer Science. "Unified distributed simulation." Ottawa, 1990.

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Shanneb, Abdelsalam Carleton University Dissertation Computer Science. "Distributed systems prototyping." Ottawa, 1994.

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Kahl, Hardy. "Transparently distributed ATHOMUX." [S.l. : s.n.], 2005. http://www.bsz-bw.de/cgi-bin/xvms.cgi?SWB12103676.

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Crumpacker, John R. "Distributed password cracking." Thesis, Monterey, California : Naval Postgraduate School, 2009. http://edocs.nps.edu/npspubs/scholarly/theses/2009/Dec/09Dec%5FCrumpacker.pdf.

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Thesis (M.S. in Computer Science)--Naval Postgraduate School, December 2009.
Thesis Advisor(s): Dinolt, George. Second Reader: Eagle, Chris. "December 2009." Description based on title screen as viewed on January 27, 2010. Author(s) subject terms: Distributed password cracking, Berkeley Open Infrastructure for Network Computing (BOINC), and John the Ripper. Includes bibliographical references (p. 63-64). Also available in print.

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Dissertations / Theses on the topic 'Distributed'

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