Rozprawy doktorskie na temat „Geo-distributed system”
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Anderson, Paul. "GeoS: A Service for the Management of Geo-Social Information in a Distributed System". Scholar Commons, 2010. https://scholarcommons.usf.edu/etd/1561.
Pełny tekst źródłaTejankar, Vinayak Prabhakar. "Optimization of Data Propagation Algorithm for Conflict-Free Replicated Data Type-based Datastores in Geo-Distributed Edge Environment". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-284683.
Pełny tekst źródłaDatareplikering erbjuder primärt tillgänglighet genom att tillhandahålla mul- tipla kopior fördelat över olika system, och utnyttjas för att göra distribuerade system skalbara i antal och över geografiska områden. Att placera en replika nära källan till en förfrågan kan dessutom signifikant reducera tiden det krävs att besvara förfrågan vilket förbättrar applikationens prestanda. Modifikatio- ner gjorda på en av kopiorna måste dock propageras till alla stående kopior för att upprätthålla datans konsistens . Över tid har många strategier föreslagits för att hantera avvägningen mellan konsistens och tillgänglighet, där majorite- ten erbjuder antingen stark eller eventuell konsistens. Dessa modeller erbjuder inte tillräcklig kompatibilitet för utveckling av moderna applikationer för geo- distribuerade (edge) miljöer.Konfliktfria replikerade datatyper (CRDT) erbjuder en ny modell av konsi- stens som kallas stark eventuell konsistens. I princip garanterar CRDTer kon- fliktfria sammanslagningar trots att uppdateringar sker i oordning, genom att använda dess matematiska egenskaper. Lasp är en koordineringsfri distribue- rad programmeringsmodell för att bygga moderna distribuerade applikationer med hjälp av CRDTer. Lasp använder skvallerprotokoll för att sprida tillstånds- förändringar till alla replikor i systemet. Den nuvarande implementationen av skvaller i Lasp är agnostiskt för applikationens beteende relaterat till effektiv propagering av uppdateringar till kritiska replikor i systemet. I det här exa- mensarbetet introducerar vi applikationsspecifik funktionalitet för att optime- ra spridandet av uppdateringar i Lasp. Den föreslagna algoritmen sprider upp- dateringarna genom att tillgodose de olika konsistenskraven för replikorna i systemet. Experimentella resultat i en topologi av 100 replikor visade att upp- dateringslatensen vid kritiska replikor med höga konsistenskrav minskas med 40–50% och att den totala bandbreddskonsumtionen i systemet minskas med 4–8% utan signifikanta negativa följder för andra replikor i systemet.
Liu, Yimei [Verfasser], Thomas Akademischer Betreuer] Wunderlich, Matthäus [Akademischer Betreuer] Schilcher i Liqiu [Akademischer Betreuer] [Meng. "Distributed geo-services based on Wireless GIS : a case study for post-quake rescue information system / Yimei Liu. Gutachter: Thomas Wunderlich ; Matthäus Schilcher ; Liqiu Meng. Betreuer: Liqiu Meng". München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1014330742/34.
Pełny tekst źródłaSilva, Marcel Santos [UNESP]. "Sistemas de informações geográficas: elementos para o desenvolvimento de bibliotecas digitais geográficas distribuídas". Universidade Estadual Paulista (UNESP), 2006. http://hdl.handle.net/11449/93711.
Pełny tekst źródłaUniversidade Estadual Paulista (UNESP)
O desenvolvimento de tecnologias de informação e comunicação aplicadas às informações geográficas cresce de forma considerável e torna mais visível o aumento de Sistemas de Informações Geográficas, principalmente em ambientes governamentais, que buscam disponibilizar a informação geográfica a um número de pessoas cada vez maior. O objetivo deste trabalho é apresentar uma arquitetura com elementos para a construção de uma Biblioteca Digital Geográfica Distribuída, utilizando os padrões e os conceitos da Ciência da Informação juntamente com o Geoprocessamento. Serão apresentados os conceitos de bibliotecas digitais, os padrões de metadados para informações geográficas, além de geo-ontologias que contribuem para melhor organização e recuperação da informação geográfica. Utilizou-se os SIGs e a teoria da Ciência da Informação, focadas em especial para o desenvolvimento de Biblioteca Digital Geográfica Distribuída. A proposta para construção de uma Biblioteca Digital Geográfica Distribuída baseia-se no princípio de cooperação entre sistemas e considera o acesso livre as informações geográficas, a interoperabilidade possibilitada pela padronização dos metadados e das geo-ontologias. A arquitetura proposta para o desenvolvimento de Bibliotecas Digitais Geográficas Distribuídas atende os requisitos de representação da informação, as formas de comunicação e o protocolo de coleta de metadados e objetos digitais, possibilitando assim, o compartilhamento dos acervos informacionais geográficos distribuídos em diferentes Bibliotecas Digitais Geográficas. Apontam-se os elos entre o Geoprocessamento e a Ciência da Informação em relação à estruturação de ambientes de informações geográficas, que possam ser acessadas via rede de computadores.
The development of technologies of information and communication applied to the Geographical information grow in a considerable way and become more visible the increase of Geographic Information Systems, mainly in governments environments, that worry in supplying the geographic information for more and more people. The target of this work is to present an architecture with elements for the construction of a distributed geographical digital library, using patterns and concepts of the Information Science together with geoprocessing. The concepts of digital libraries and the patterns of metadata for geographical information will be presented, besides the geo-ontologies that contribute to better organization and recovery of geographical information. It was used the Geographic Information Systems and the theory of Information Science, focused mainly to the development of distributed geographical digital library.The proposal for construction of the distributed geographical digital library is on the principle of cooperation among systems and it considers the free access to geographical information, the interoperability facilitated by the standardization of the metadatas and geo-ontologies. The architecture proposed for the development of distributed geographical digital libraries assists the requirements of representations of the information, ways of communications and collection protocols for metadatas and digital objects, facilitating thus, the share of collections of geographical informations distributed at several Geographical Digital Libraries. The links between the geoprocessing and Information Science is pointed out with regard to the structuring of geographical information environment that can be accessed through computers network.
Qureshi, Asfandyar. "Power-Demand Routing in massive geo-distributed systems". Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62430.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (p. 165-171).
There is an increasing trend toward massive, geographically distributed systems. The largest Internet companies operate hundreds of thousands of servers in multiple geographic locations, and are growing at a fast clip. A single system's servers and data centers can consume many megawatts of electricity, as much as tens of thousands of US homes. Two important concerns have arisen: rising electric bills; and growing carbon footprints. Our work develops a new traffic engineering technique that can be used to address both these areas of concern. We introduce Power-Demand Routing (PDR), a technique that redistributes traffic between replicas with the express purpose of spatially redistributing the system's power consumption, in order to reduce operating costs. Cost can be described in monetary terms or in terms of pollution. Within existing Internet services, each client request requires a meaningful amount of marginal energy at the server. Thus, by rerouting requests from a server at one geographic location to another, we can spatially shift the systems marginal power consumption at Internet speeds. We show how PDR can be used to reduce electric bills. We describe how to couple request routing policy to real-time price signals from wholesale electricity markets. In response to price-differentials, PDR skews client load across a system's clusters and pushes server power-demand into the least expensive regions. Our analysis quantifies the potential reduction in energy costs. We use simulations driven by empirical data and models: we collected a real-world request traffic workload in collaboration with Akamai; constructed data center energy models; and compiled a database of historical electricity market prices. We conclude that existing systems can use PDR to cut their annual electric bills by millions of dollars. We also show how PDR can be used to reduce carbon footprints. Not all joules are created equal and in power pools like the grid the environmental impact per joule varies geographically and in time. We show how to construct carbon cost functions that can be used with PDR to dynamically push a system's power-demand toward clean energy.
by Asfandyar Qureshi.
Ph.D.
Bogdanov, Kirill. "Reducing Long Tail Latencies in Geo-Distributed Systems". Licentiate thesis, KTH, Network Systems Laboratory (NS Lab), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-194729.
Pełny tekst źródłaDatabehandlingstjänster är en välintegrerad del av det moderna samhället. Miljontals människor förlitar sig dagligen på dessa tjänster för kommunikation, samordning, handel, och åtkomst till information. För att möta höga krav implementeras och placeras många populära tjänster som geo-fördelning applikationer ovanpå tredje parters virtuella molntjänster. Det ligger emellertid i sakens natur att sådana utplaceringar resulterar i varierande prestanda. För att leverera höga servicekvalitetskrav behöver sådana system sträva efter att ständigt anpassa sig efter ändrade förutsättningar genom att övervaka tillståndsändringar och ta realtidsbeslut, som till exempel val av server peering, replika placering, och val av kvorum. Den här avhandlingen avser att förbättra kvaliteten på realtidsbeslut tagna av geo-fördelning system. Detta kan uppnås genom: (1) en bättre förståelse av underliggande utplaceringsvillkor, (2) systematisk och noggrann testning av beslutslogik redan implementerad i dessa system, och (3) en tydlig inblick i nätverket och systemtillstånd som tillåter dessa tjänster att utföra mer informerade beslut. Vi utförde en långsiktig korsa datacenter latensmätning av Amazons EC2 molntjänst. Mätdata användes sedan till att kvantifiera variationen av nätverkstillstånd och demonstrera dess inverkan på prestanda för system placerade ovanpå denna molntjänst. Därnäst validerades en applikations beslutslogik vanlig i populära lagringssystem genom att undersöka replika valalgoritmen. GeoPerf, ett verktyg som tillämpar symbolisk exekvering och lättviktsmodellering för systematisk testning av replika valalgoritmen, användes för att testa två populära lagringssystem och vi hittade en bugg i båda. Genom traceroute och envägslatensmätningar över EC2 demonstrerar vi ihängande korrelation mellan nätverksvägar och nätverkslatens. Vi introducerar också EdgeVar, ett verktyg som frikopplar dirigering och trängsel baserat på förändringar i nätverkslatens. Genom att tillhandahålla denna ytterligare information förbättrade vi kvaliteten på latensuppskattningen och stabiliteten på nätverkets val av väg. Slutligen introducerade vi Tectonic, ett verktyg som följer en applikations begäran och gensvar på både användare-läge och kernel-läge. Tillsammans med EdgeVar förses en komplett bild av fördröjningar associerade med varje beräkningssteg av begäran och gensvar. Med Tectonic kunde vi analysera inverkan av att dela CPUer i en virtuell miljö och kan avslöja hypervisor schemaläggningsprinciper. Vi argumenterar för betydelsen av att känna till dessa principer och föreslå användningen av de i beslutsprocessen.
QC 20161101
Falgert, Marcus. "Geo-distributed application deployment assistance based on past routing information". Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-206970.
Pełny tekst źródłaToumlilt, Ilyas. "Colony : a Hybrid Consistency System for Highly-Available Collaborative Edge Computing". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS447.
Pełny tekst źródłaImmediate response, autonomy and availability is brought to edge applications, such as gaming, cooperative engineering, or in-the-field information sharing, by distributing and replicating data at the edge. However, application developers and users demand the highest possible consistency guarantees, and specific support for group collaboration. To address this challenge, COLONY guarantees Transactional Causal Plus Consistency (TCC+) globally, dovetailing with Snapshot Isolation within edge groups. To help with scalability, fault tolerance and security, its logical communication topology is tree-like, with replicated roots in the core cloud, but with the flexibility to migrate a node or a group. Despite this hybrid approach, applications enjoy the same semantics everywhere in the topology. Our experiments show that local caching and peer groups improve throughput and response time significantly, performance is not affected in offline mode, and that migration is seamless
Vasilas, Dimitrios. "A flexible and decentralised approach to query processing for geo-distributed data systems". Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS132.
Pełny tekst źródłaThis thesis studies the design of query processing systems, across a diversity of geo-distributed settings. Optimising performance metrics such as response time, freshness, or operational cost involves design decisions, such as what derived state (e.g., indexes, materialised views, or caches) to maintain, and how to distribute and where to place the corresponding computation and state. These metrics are often in tension, and the trade-offs depend on the specific application and/or environment. This requires the ability to adapt the query engine's topology and architecture, and the placement of its components. This thesis makes the following contributions: - A flexible architecture for geo-distributed query engines, based on components connected in a bidirectional acyclic graph. - A common microservice abstraction and API for these components, the Query Processing Unit (QPU). A QPU encapsulates some primitive query processing task. Multiple QPU types exist, which can be instantiated and composed into complex graphs. - A model for constructing modular query engine architectures as a distributed topology of QPUs, enabling flexible design and trade-offs between performance metrics. - Proteus, a QPU-based framework for constructing and deploying query engines. - Representative deployments of Proteus and experimental evaluation thereof
Silva, Marcel Santos. "Sistemas de informações geográficas : elementos para o desenvolvimento de bibliotecas digitais geográficas distribuídas /". Marília : [s.n.], 2006. http://hdl.handle.net/11449/93711.
Pełny tekst źródłaBanca: Plácida Leopoldina Ventura Amorim da Costa Santos
Banca: Sérgio Antonio Rohm
Resumo: O desenvolvimento de tecnologias de informação e comunicação aplicadas às informações geográficas cresce de forma considerável e torna mais visível o aumento de Sistemas de Informações Geográficas, principalmente em ambientes governamentais, que buscam disponibilizar a informação geográfica a um número de pessoas cada vez maior. O objetivo deste trabalho é apresentar uma arquitetura com elementos para a construção de uma Biblioteca Digital Geográfica Distribuída, utilizando os padrões e os conceitos da Ciência da Informação juntamente com o Geoprocessamento. Serão apresentados os conceitos de bibliotecas digitais, os padrões de metadados para informações geográficas, além de geo-ontologias que contribuem para melhor organização e recuperação da informação geográfica. Utilizou-se os SIGs e a teoria da Ciência da Informação, focadas em especial para o desenvolvimento de Biblioteca Digital Geográfica Distribuída. A proposta para construção de uma Biblioteca Digital Geográfica Distribuída baseia-se no princípio de cooperação entre sistemas e considera o acesso livre as informações geográficas, a interoperabilidade possibilitada pela padronização dos metadados e das geo-ontologias. A arquitetura proposta para o desenvolvimento de Bibliotecas Digitais Geográficas Distribuídas atende os requisitos de representação da informação, as formas de comunicação e o protocolo de coleta de metadados e objetos digitais, possibilitando assim, o compartilhamento dos acervos informacionais geográficos distribuídos em diferentes Bibliotecas Digitais Geográficas. Apontam-se os elos entre o Geoprocessamento e a Ciência da Informação em relação à estruturação de ambientes de informações geográficas, que possam ser acessadas via rede de computadores.
Abstract: The development of technologies of information and communication applied to the Geographical information grow in a considerable way and become more visible the increase of Geographic Information Systems, mainly in governments environments, that worry in supplying the geographic information for more and more people. The target of this work is to present an architecture with elements for the construction of a distributed geographical digital library, using patterns and concepts of the Information Science together with geoprocessing. The concepts of digital libraries and the patterns of metadata for geographical information will be presented, besides the geo-ontologies that contribute to better organization and recovery of geographical information. It was used the Geographic Information Systems and the theory of Information Science, focused mainly to the development of distributed geographical digital library.The proposal for construction of the distributed geographical digital library is on the principle of cooperation among systems and it considers the free access to geographical information, the interoperability facilitated by the standardization of the metadatas and geo-ontologies. The architecture proposed for the development of distributed geographical digital libraries assists the requirements of representations of the information, ways of communications and collection protocols for metadatas and digital objects, facilitating thus, the share of collections of geographical informations distributed at several Geographical Digital Libraries. The links between the geoprocessing and Information Science is pointed out with regard to the structuring of geographical information environment that can be accessed through computers network.
Mestre
Franca, Rezende Tuanir. "Leaderless state-machine replication : from fail-stop to Byzantine failures". Electronic Thesis or Diss., Institut polytechnique de Paris, 2021. http://www.theses.fr/2021IPPAS016.
Pełny tekst źródłaModern distributed services are expected to be highly available, as our societies have been growing increasingly dependent on them. The common way to achieve high availability is through the replication of data in multiple service replicas. In this way, the service remains operational in case of failures as clients can be relayed to other working replicas. In distributed systems, the classic technique to implement such fault-tolerant services is called State-Machine Replication (SMR), where a service is defined as a deterministic state-machine and each replica keeps a local copy of the machine. To guarantee that the service remains consistent, replicas coordinate with each other and agree on the order of transitions to be applied to their copies of the state-machine. The replication performed by modern Internet services spans across several geographical locations (geo-replication). This allows for increased availability and low latency, since clients can communicate with the closest geo-graphical replica. Due to their reliance on a leader replica, classical SMR protocols offer limited scalability and availability under this setting. To solve this problem, recent protocols follow instead a leaderless approach, in which each replica is able to make progress using a quorum of its peers. These new leaderless protocols are complex and each one presents an ad-hoc approach to leaderlessness. The first contribution of this thesis is a framework that captures the essence of Leaderless State-Machine Replication (Leaderless SMR) and the formalization of some of its limits. Due to the increasingly sensitive nature of replicated services, leveraging simple benign failures is no longer enough. Recent research is headed towards developing protocols that support arbitrary behavior of some replicas (Byzantine failures) and that also thrive in a geo-replicated environment. An example of this new type of sensitive replicated services that has been the focus of a lot of research are blockchains. Blockchains are powered by Byzantine replication protocols adapted to work over hundreds or even thousands of replicas. When the membership control over such replicas is open, that is, anyone can run a replica, we say the blockchain is permissionless. In the converse case, when the membership is controlled by a set of known entities like companies, we say the blockchain is permissioned. When such Byzantine protocols follow the classic leader-driven approach they suffer from scalability and availability issues, similarly to their non-byzantine counterparts. In the second part of this thesis, we adapt our framework to support Byzantine failures and present the first framework for Byzantine Leaderless SMR. Furthermore, we show that when properly instantiated it allows to sidestep the scalability problems in leader-driven Byzantine SMR protocols for permissioned blockchains
Darrous, Jad. "Scalable and Efficient Data Management in Distributed Clouds : Service Provisioning and Data Processing". Thesis, Lyon, 2019. http://www.theses.fr/2019LYSEN077.
Pełny tekst źródłaThis thesis focuses on scalable data management solutions to accelerate service provisioning and enable efficient execution of data-intensive applications in large-scale distributed clouds. Data-intensive applications are increasingly running on distributed infrastructures (multiple clusters). The main two reasons for such a trend are 1) moving computation to data sources can eliminate the latency of data transmission, and 2) storing data on one site may not be feasible given the continuous increase of data size.On the one hand, most applications run on virtual clusters to provide isolated services, and require virtual machine images (VMIs) or container images to provision such services. Hence, it is important to enable fast provisioning of virtualization services to reduce the waiting time of new running services or applications. Different from previous work, during the first part of this thesis, we worked on optimizing data retrieval and placement considering challenging issues including the continuous increase of the number and size of VMIs and container images, and the limited bandwidth and heterogeneity of the wide area network (WAN) connections.On the other hand, data-intensive applications rely on replication to provide dependable and fast services, but it became expensive and even infeasible with the unprecedented growth of data size. The second part of this thesis provides one of the first studies on understanding and improving the performance of data-intensive applications when replacing replication with the storage-efficient erasure coding (EC) technique
Chen, Yi-Chia, i 陳奕佳. "An approach based on matching theory to distributed deployment of NFV-based network services to geo-distributed edge computing systems". Thesis, 2019. http://ndltd.ncl.edu.tw/handle/h7kasp.
Pełny tekst źródła國立交通大學
資訊科學與工程研究所
107
With both Network Function Virtualization (NFV) and Multi-access Edge Computing (MEC) environment, network service providers can deploy their NFV-based network services on the edge servers maintained by edge service providers (ESPs) to serve end users. Nevertheless, determining which ESP to lease resource and how much to pay for the deployment will become an important issue for the network service providers. For the ESPs, determining which network serive to serve and how much to charge from its provider is also an important issue. We proposed a two-layer mechanism of matching game for the deployment of network services to the ESPs. Specifically, the upper layer is the bargaining process between network services and ESPs, we use matching auction; the lower layer is resource allocation for VNFs within an ESP, we use one-to-many matching model. The proposed mechanism can provide a weakly stable result, that is, there will be no network service that is more favorable than all ESPs' current matching results. However, there may exist a network service which can have more profit if it change its current partner. We simulated the proposed mechanisms and showed that we can have a higher average number of served network services, and both ESPs and network service providers can have higher profits.
Fouto, Pedro Filipe Veiga. "A novel causally consistent replication protocol with partial geo-replication". Master's thesis, 2018. http://hdl.handle.net/10362/63048.
Pełny tekst źródłaFernandes, Flávio Duarte Pacheco. "LHView: Location Aware Hybrid Partial View". Master's thesis, 2017. http://hdl.handle.net/10362/66268.
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