Literatura académica sobre el tema "Geo-distributed system"
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Artículos de revistas sobre el tema "Geo-distributed system"
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Oh, Kwangsung, Nan Qin, Abhishek Chandra, and Jon Weissman. "Wiera: Policy-Driven Multi-Tiered Geo-Distributed Cloud Storage System." IEEE Transactions on Parallel and Distributed Systems 31, no. 2 (2020): 294–305. http://dx.doi.org/10.1109/tpds.2019.2935727.
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Hildred, Joshua, Michael Abebe, and Khuzaima Daudjee. "Caerus: Low-Latency Distributed Transactions for Geo-Replicated Systems." Proceedings of the VLDB Endowment 17, no. 3 (2023): 469–82. http://dx.doi.org/10.14778/3632093.3632109.
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Distributed deterministic database systems achieve high transaction throughput for geographically replicated data. Supporting transactions with ACID guarantees requires deterministic databases to order transactions globally to dictate execution order. In a geographically distributed environment, ordering transactions globally can take multiple wide-area network (WAN) round trips of messaging, which adds significant latency to transaction response times, leading to poor user experiences. To improve the response time of transactions in deterministic databases, we propose an ordering protocol that can include a transaction in the global order in a single WAN round trip to the primary regions of the data items within the transaction's read and write set. The protocol reduces the cost of determining the global order for all transactions by leveraging deterministic merging of partial sequences of transactions per geographic region. We implement the protocol in Caerus, our geo-replicated deterministic database system that serializably commits and replicates transactions after a delay of only a single WAN round trip of messaging. Using popular workload benchmarks over geographically replicated data in Azure, we show that Caerus outperforms state-of-the-art comparison systems to deliver low-latency transaction execution.
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Shi, Bin, Dan Zhang, Honghu Zhu, et al. "DFOS Applications to Geo-Engineering Monitoring." Photonic Sensors 11, no. 2 (2021): 158–86. http://dx.doi.org/10.1007/s13320-021-0620-y.
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AbstractOptical fiber sensing technology has developed rapidly since the 1980s with the development of the optical fiber and fiber optical communication technology. It is a new type of sensing technology that uses light as a carrier and optical fiber as a medium to sense and transmit external signals (measurands). Distributed fiber optical sensors (DFOS) can continuously measure the external physical parameters distributed along the geometric path of the optical fiber. Meanwhile, the spatial distribution and change information of the measured physical parameters over time can be obtained. This technology has unmatched advantages over traditional point-wise and electrical measurement monitoring technologies. This paper summarizes the state-of-the-art research of the application of the distributed optical fiber sensing technology in geo-engineering in the past 10 years, mainly including the advantages of DFOS, the challenges in geo-engineering monitoring, related fundamental theoretical issues, sensing performance of the optical sensing cables, distributed optical fiber monitoring system for geo-engineering, and applications of optical fiber sensing technology in geo-engineering.
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Gou, Liang, Geng Xin Zhang, Zhi Dong Xie, Zhi Ping Xu, and Hong Wei Long. "Payload-Distributed GEO Communication Satellite System and Opportunistic Network Coding Based Cooperative Information Exchange." Applied Mechanics and Materials 519-520 (February 2014): 1005–11. http://dx.doi.org/10.4028/www.scientific.net/amm.519-520.1005.
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Fractionated Spacecraft is a concept which transforms a traditional monolithic spacecraft into a network of elements where a free-flying payload module is supported by nearby free-flying infrastructure modules. In this paper, we propose a novel concept named as Payload-Distributed GEO Communication Satellite System (PD-GEO) which divides the traditional GEO communication satellite into several modules. Those modules can be reconfigured, added, or exchanged independently from the others, and be reused over several missions. Then, for the purpose of reliable and high-efficient data transmission in this system, an opportunistic network coding based cooperative information exchange (ONC2IE) scheme was presented. Qualitative analysis and extensive simulations demonstrate the effectiveness and efficiency of ONC2IE.
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Wang, Changxu, Yuanzhi He, and Chengwu Qi. "Analysis of Grating Lobe Effects on GEO DSC Distributed Antennas." Applied Sciences 13, no. 19 (2023): 10912. http://dx.doi.org/10.3390/app131910912.
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Traditional single-antenna systems have inherent limitations in terms of antenna gain, anti-interference capability, and flexibility. To overcome these challenges, satellite-mounted distributed antenna systems disperse multiple antennas at different positions on the satellite to improve the reception quality and signal-to-noise ratio of satellite signals, enhancing the performance of the satellite communication system without additional bandwidth or transmission power. However, the dispersed locations and long distances between antennas on the satellite result in less compact spacing compared to terrestrial distributed antennas, leading to the generation of a significant number of grating lobes. The distributed satellite cluster (DSC) approach revolutionizes the traditional mode of satellite utilization, enabling close collaboration among distributed loads. In this study, we analyzed the impact of grating lobes produced by DSC distributed antennas in geostationary Earth orbit (GEO) and simulated the grating lobe patterns of two 1 m circular aperture satellite antenna arrays in GEO. The simulation results revealed that the relative position change of the satellites affected the width and number of interference fringes in a certain ground area, while change in the carrier phase led to the translation of the interference fringes. To mitigate the grating lobes, we employed a sparse array technique. The simulation results demonstrated that the sparse array effectively suppressed the grating lobes but at the expense of a decrease in the sidelobe level and beamwidth.
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Gharbia, Salem S., Laurence Gill, Paul Johnston, and Francesco Pilla. "GEO-CWB: GIS-Based Algorithms for Parametrising the Responses of Catchment Dynamic Water Balance Regarding Climate and Land Use Changes." Hydrology 7, no. 3 (2020): 39. http://dx.doi.org/10.3390/hydrology7030039.
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Parametrising the spatially distributed dynamic catchment water balance is a critical factor in studying the hydrological system responses to climate and land use changes. This study presents the development of a geographic information system (GIS)-based set of algorithms (geographical spatially distributed water balance model (GEO-CWB)), which is developed from integrating physical, statistical, and machine learning models. The GEO-CWB tool has been developed to simulate and predict future spatially distributed dynamic water balance using GIS environment at the catchment scale in response to the future changes in climate variables and land use through a user-friendly interface. The tool helps in bridging the gap in quantifying the high-resolution dynamic water balance components for the large catchments by reducing the computational costs. Also, this paper presents the application and validation of GEO-CWB on the Shannon catchment in Ireland as an example of a large and complicated hydrological system. It can be concluded that climate and land use changes have significant effects on the spatial and temporal patterns of the different water balance components of the catchment.
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Nguyen, Cuong D. T., Johann K. Miller, and Daniel J. Abadi. "Detock: High Performance Multi-region Transactions at Scale." Proceedings of the ACM on Management of Data 1, no. 2 (2023): 1–27. http://dx.doi.org/10.1145/3589293.
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Many globally distributed data stores need to replicate data across large geographic distances. Since synchronously replicating data across such distances is slow, those systems with high consistency requirements often geo-partition data and direct all linearizable requests to the primary region of the accessed data. This significantly improves performance for workloads where most transactions access data close to where they originate from. However, supporting serializable multi-geo-partition transactions is a challenge, and they often degrade the performance of the whole system. This becomes even more challenging when they conflict with single-partition requests, where optimistic protocols lead to high numbers of aborts, and pessimistic protocols lead to high numbers of distributed deadlocks. In this paper, we describe the design of concurrency control and deadlock resolution protocols, built within a practical, complete implementation of a geographically replicated database system called Detock, that enables processing strictly-serializable multi-region transactions with near-zero performance degradation at extremely high conflict and order of magnitude higher throughput relative to state-of-the art geo-replication approaches, while improving latency by up to a factor of 5.
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Satuluri, Victoria, and Ratna Babu Yellamati. "Design of Middleware and Software Embedded Development Kit For Area Based Distributed Mobile Cache System." International Journal of Electrical and Electronics Research 3, no. 3 (2015): 44–49. http://dx.doi.org/10.37391/ijeer.030301.
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Nowadays a new area-based distributed mobile cache system and a sustainable distributed Geo-cast technology enables data caching temporarily in a designated local area using short-range communication technologies such as Bluetooth and Wi-Fi. This system doesn’t need servers and infrastructure network. To enhance the short-range communications as a time-offset communication in a physical world the caching capability is needed. Due to this advantage it is sure to adopt a new location-based communication services. The proposed work is frames a developed middleware for a widespread embedded OS and a software development kit with an open application programming interface. The proposed middleware is expected to prompt the third-party developers to produce various applications using this platform and provided with some pseudo-code. And also explained the methods for using this platform by an implemented geo-location social game.
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Jahn, M. W., P. E. Bradley, M. Al Doori, and M. Breunig. "TOPOLOGICALLY CONSISTENT MODELS FOR EFFICIENT BIG GEO-SPATIO-TEMPORAL DATA DISTRIBUTION." ISPRS Annals of Photogrammetry, Remote Sensing and Spatial Information Sciences IV-4/W5 (October 23, 2017): 65–72. http://dx.doi.org/10.5194/isprs-annals-iv-4-w5-65-2017.
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Geo-spatio-temporal topology models are likely to become a key concept to check the consistency of 3D (spatial space) and 4D (spatial + temporal space) models for emerging GIS applications such as subsurface reservoir modelling or the simulation of energy and water supply of mega or smart cities. Furthermore, the data management for complex models consisting of big geo-spatial data is a challenge for GIS and geo-database research. General challenges, concepts, and techniques of big geo-spatial data management are presented. In this paper we introduce a sound mathematical approach for a topologically consistent geo-spatio-temporal model based on the concept of the incidence graph. We redesign DB4GeO, our service-based geo-spatio-temporal database architecture, on the way to the parallel management of massive geo-spatial data. Approaches for a new geo-spatio-temporal and object model of DB4GeO meeting the requirements of big geo-spatial data are discussed in detail. Finally, a conclusion and outlook on our future research are given on the way to support the processing of geo-analytics and -simulations in a parallel and distributed system environment.
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Song, Weiwei, Qiong Wu, Xiaopeng Gong, Fu Zheng, and Yidong Lou. "Corrections of BDS Code Multipath Error in Geostationary Orbit Satellite and Their Application in Precise Data Processing." Sensors 19, no. 12 (2019): 2737. http://dx.doi.org/10.3390/s19122737.
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Multipath error is a main error source in Global Navigation Satellite System (GNSS) data processing, which cannot be removed by a differential technique because of the strong relationship with the environment around the station. The multipath effect of the code observables is more complex than that of the carrier-phase observables, especially for BeiDou Navigation Satellite System (BDS) geostationary orbit (GEO) satellites. In this contribution, we deeply analyzed the characteristic and effect on the precise data processing of GEO satellite multipath errors based on a large number of permanent GNSS stations. A linear combination of code and carrier-phase observables was used to analyze the characteristics of repeatability for BDS GEO’s multipath. Then, a correction method was proposed to eliminate the multipath error of the GEO code observables, based on wavelet transform. The experiment data were collected at 83 globally distributed stations, from multi-GNSS experiments and national BDS augmentation systems, from days 32 to 66 in 2017. The results show that the systematic multipath variation component of the GEO code observables can be obtained with wavelet transform, which can significantly contribute to correcting the multipath error of GEO satellites. The average root mean square error (RMSE) of the multipath series is decreased by approximately 19.5%, 20.2%, and 7.5% for B1, B2, and B3, respectively. In addition, some experiments, including ionospheric delay extraction and satellite clock estimation, were conducted in simulated real-time mode in order to validate the effect of the correction methods. For the ionospheric delay estimation, the average RMSE of the slant ionospheric delay is reduced by approximately 15.5%. Moreover, the multipath correction can contribute greatly to shortening the convergence time of the satellite clock estimation of the BDS GEO satellites.
Tesis sobre el tema "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.
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Applications and services that take advantage of social data usually infer social relationships using information produced only within their own context, using a greatly simplified representation of users' social data. We propose to combine social information from multiple sources into a directed and weighted social multigraph in order to enable novel socially-aware applications and services. We present GeoS, a geo-social data management service which implements a representative set of social inferences and can run on a decentralized system. We demonstrate GeoS' potential for social applications on a collection of social data that combines collocation information and Facebook friendship declarations from 100 students. We demonstrate its performance by testing it both on PlanetLab and a LAN with a realistic workload for a 1000 node graph.
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Tejankar, 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.
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Replication primarily provides data availability by having multiple copies over different systems and is exploited to make distributed systems scalable in num- bers and geographical areas. Placing a replica closer to the source of request can also significantly reduce the time required to service the request, improv- ing applications’ performance. However, modifications done at a single copy need to be propagated to all the standing copies to maintain the data’s consis- tency. Over the years, numerous strategies have been proposed for handling the tradeoff between consistency and availability, of which the majority pro- vides either strong consistency or eventual consistency. These models do not provide sufficient compatibility for developing modern applications for geo- distributed (edge) environments.Conflict-Free Replicated Data Types (CRDT) provides a new model of consistency referred to as strong eventual consistency. In principle, CRDTs guarantee conflict-free merge even when the updates arrive out of order using simple mathematical properties. Lasp is a coordination free distributed pro- gramming model for building modern distributed applications using CRDTs. Lasp uses a gossip protocol for disseminating state changes to all replicas in the system. The current implementation of gossip in Lasp is agnostic to the application’s behavior in propagating the updates efficiently to critical repli- cas in the system. In the thesis, we introduce an application-specific feature to optimize the dissemination of updates in Lasp. The proposed algorithm propagates the updates by catering to the different consistency requirements of the replicas in the system. The experimental results on a topology of 100 replicas found that the update latency at critical replicas with high consistency requirements is reduced by 40–50%, and the total bandwidth consumption in the system is reduced by 4–8% without significant repercussion on other repli- cas in the system.<br>Datareplikering 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.
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Liu, Yimei [Verfasser], Thomas Akademischer Betreuer] Wunderlich, Matthäus [Akademischer Betreuer] Schilcher, and 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.
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Silva, 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.
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santos_ms_me_mar.pdf: 2277134 bytes, checksum: 2c1d35de92755006ed8a8f0016328bfe (MD5)<br>Universidade Estadual Paulista (UNESP)<br>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.<br>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.
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Qureshi, Asfandyar. "Power-Demand Routing in massive geo-distributed systems." Thesis, Massachusetts Institute of Technology, 2010. http://hdl.handle.net/1721.1/62430.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.<br>Cataloged from PDF version of thesis.<br>Includes bibliographical references (p. 165-171).<br>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.<br>by Asfandyar Qureshi.<br>Ph.D.
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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.
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Computing services are highly integrated into modern society. Millions of people rely on these services daily for communication, coordination, trading, and accessing to information. To meet high demands, many popular services are implemented and deployed as geo-distributed applications on top of third party virtualized cloud providers. However, the nature of such deployment provides variable performance characteristics. To deliver high quality of service, such systems strive to adapt to ever-changing conditions by monitoring changes in state and making run-time decisions, such as choosing server peering, replica placement, and quorum selection. In this thesis, we seek to improve the quality of run-time decisions made by geo-distributed systems. We attempt to achieve this through: (1) a better understanding of the underlying deployment conditions, (2) systematic and thorough testing of the decision logic implemented in these systems, and (3) by providing a clear view into the network and system states which allows these services to perform better-informed decisions. We performed a long-term cross datacenter latency measurement of the Amazon EC2 cloud provider. We used this data to quantify the variability of network conditions and demonstrated its impact on the performance of the systems deployed on top of this cloud provider. Next, we validate an application’s decision logic used in popular storage systems by examining replica selection algorithms. We introduce GeoPerf, a tool that uses symbolic execution and lightweight modeling to perform systematic testing of replica selection algorithms. We applied GeoPerf to test two popular storage systems and we found one bug in each. Then, using traceroute and one-way delay measurements across EC2, we demonstrated persistent correlation between network paths and network latency. We introduce EdgeVar, a tool that decouples routing and congestion based changes in network latency. By providing this additional information, we improved the quality of latency estimation, as well as increased the stability of network path selection. Finally, we introduce Tectonic, a tool that tracks an application’s requests and responses both at the user and kernel levels. In combination with EdgeVar, it provides a complete view of the delays associated with each processing stage of a request and response. Using Tectonic, we analyzed the impact of sharing CPUs in a virtualized environment and can infer the hypervisor’s scheduling policies. We argue for the importance of knowing these policies and propose to use them in applications’ decision making process.<br>Databehandlingstjänster 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.<br><p>QC 20161101</p>
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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.
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Cloud computing platforms allow users to deploy geographically distributed applications on servers around the world. Applications may be simple to deploy on these platforms, but it is up to the user and the application to decide which regions and servers to use for application placement. Furthermore, network conditions and routing between the geo-distributed servers change over time, which can lead to sub-optimal performance of applications deployed on such servers. A user could either employ a static deployment configuration of servers, or attempt to use a more dynamic configuration. However, both have inherent limitations. A static configuration will be sub-optimal, as it will be unable to adapt to changing network conditions. A more dynamic approach where an application could switch over or transition to a more suitable server could be beneficial, but this can be very complex in practice. Furthermore, such a solution is more about adapting to change as it happens, and not beforehand. This thesis will investigate the possibility of forecasting impending routing changes between servers, by leveraging messages generated by the Border Gateway Protocol (BGP) and past knowledge about routing changes. BGP routers can delay BGP updates due to factors such as the minimum route advertisement interval (MRAI). Thus, out proposed solution involves forwarding BGP updates downstream in the network, before BGP routers process them. As routing between servers changes, so does the latency, meaning that the latency then could be predicted to some degree. This observation could be applied to realize when the latency to a server increases or decreases past another server. This in turn facilitates the decision process of selecting the most optimal servers in terms of latency for application deployment. The solution presented in this thesis can successfully predict routing changes between end-points in an enclosed environment, and inform users ahead of time that the latency is about to change. The time gained by such predictions depend on factors such as the number of ASs between the end-points, the MRAI, and the update processing delay imposed on BGP routers. Time gains between tens of milliseconds to over 2 minutes has been observed.
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Toumlilt, Ilyas. "Colony : a Hybrid Consistency System for Highly-Available Collaborative Edge Computing." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS447.
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La distribution et la réplication des données en périphérie du réseau apportent une réponse immédiate, une autonomie et une disponibilité aux applications de périphérie, telles que les jeux, l’ingénierie coopérative ou le partage d’informations sur le terrain. Cependant, les développeurs d’applications et les utilisateurs exigent les meilleures garanties de cohérence possibles, ainsi qu’un support spécifique pour la collaboration de groupe. Pour relever ce défi, Colony garantit la cohérence Transactional Causal Plus Consistency (TCC+) à échelle planétaire, en complément de l’isolation des instantanés au sein des groupes de périphérie. Pour favoriser le passage à l’échelle, la tolérance aux pannes et la sécurité, sa topologie de communication logique est arborescente, avec des racines répliquées dans le nuage principal, mais avec la possibilité de migrer un nœud ou un groupe. Malgré cette approche hybride, les applications bénéficient de la même sémantique partout dans la topologie. Nos expériences montrent que la mise en cache locale et les groupes collaboratifs améliorent considérablement le débit et le temps de réponse, que les performances ne sont pas affectées en mode hors ligne et que la migration est transparente<br>Immediate 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
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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.
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Cette thèse présente l'étude de la conception de systèmes de traitement de requêtes dans divers cadres géo-distribués. L'optimisation des mesures de performance telles que le temps de réponse, la fraîcheur ou le coût opérationnel implique des décisions de conception tel que le choix de l’état dérivé (indices, vues matérialisées, caches par ex.) à construire et maintenir, et la distribution et le placement de ces derniers et de leurs calculs. Ces métriques sont souvent opposées et les compromis dépendent de l'application et/ou de la spécificité de l'environnement. La capacité d'adapter la topologie et l'architecture du système de traitement de requêtes devient alors essentielle, ainsi que le placement de ses composants. Cette thèse apporte les contributions suivantes : - Une architecture flexible pour les systèmes de traitement de requêtes géo-distribués, basée sur des composants connectés dans un graphe bidirectionnel acyclique. - Une abstraction de micro-service et une API communes pour ces composants, le Query Processing Unit (QPU). Un QPU encapsule une tâche de traitement de requête primitive. Il existe plusieurs types de QPU qui peuvent être instanciés et composés en graphes complexes. - Un modèle pour construire des architectures de systèmes de traitement de requêtes modulaires composées d’une topologie distribuée de QPUs, permettant une conception flexible et des compromis selon les mesures de performance visées. - Proteus, un framework basé sur les QPU, permettant la construction et le déploiement de systèmes de traitement de requêtes. - Déploiements représentatifs de systèmes de traitement de requêtes à l'aide de Proteus, et leur évaluation expérimentale<br>This 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
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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.
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Orientador: Silvana Aparecida Borsetti Gregório Vidotti<br>Banca: Plácida Leopoldina Ventura Amorim da Costa Santos<br>Banca: Sérgio Antonio Rohm<br>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.<br>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.<br>Mestre
Libros sobre el tema "Geo-distributed system"
Capítulos de libros sobre el tema "Geo-distributed system"
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Yu, Jiongyu, Weigang Wu, Di Yang, and Ning Huang. "MRFS: A Distributed Files System with Geo-replicated Metadata." In Algorithms and Architectures for Parallel Processing. Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11194-0_21.
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Dou, Wanchun, Xiaolong Xu, and Shui Yu. "Industrial-Metadata Intelligent Service for Geo-Distributed File System." In Intelligent Industrial Internet Systems. Springer Nature Singapore, 2023. http://dx.doi.org/10.1007/978-981-99-5732-3_3.
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Zhang, Chi, Hui Li, Xuan An Song, Jie Cheng, and Li Jie Wang. "LoS-MIMO Channel Capacity of Distributed GEO Satellites Communication System Over the Sea." In Lecture Notes in Electrical Engineering. Springer Singapore, 2020. http://dx.doi.org/10.1007/978-981-13-9409-6_231.
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Bao, Yixin, and Chuan Wu. "Geo-Distributed Big Data Analytics Systems." In Smart Data. Chapman and Hall/CRC, 2019. http://dx.doi.org/10.1201/9780429507670-8.
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Sindoni, Giuseppe, and Matteo Massenzio. "An Open Data platform for decision making in local public administration." In Proceedings e report. Firenze University Press and Genova University Press, 2023. http://dx.doi.org/10.36253/979-12-215-0106-3.51.
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This paper presents the Milan Open Data (OD) platform as a means to provide statistics and data in the framework of “Data-Driven Milan”, a city where policy decisions are taken in an “informed and aware” way using data. Open Data are ever more important in providing citizen communities with useful information. Over the last 10 years, the municipality of Milan has developed its OD platform from an experimental portal to a fully-fledged portal with more than 1,600 datasets, implemented a Linked Open Data (LOD) system and 8 advanced data visualization projects, and produced OD policies and operating guidelines. The OD portal is based on the CKAN technology, which makes datasets available via both download and Application Programming Interfaces. It currently has about 9,000 unique visitors per month. Data are also published as tables on the statistical portal and maps on the geo-portal. A single entry point to the three portals is about to be released. The advanced visualization projects make data available as reader-friendly graphics. Depending on its topic, a project might be a storytelling of the city through key statistics, a means to communicate the administration’s achievements, or a “data democratization” operation, such as “Open bilancio”, which publishes detailed information about the municipality’s annual budget. LOD are semantically enriched and machine-readable data that help to implement data interoperability between distributed systems. The ongoing LOD automation project aims to improve the current system by minimizing manual operations in the dataset lifecycle. Three Municipal Resolutions have been issued to define OD governance: the first establishes that data are released under an Open License, to promote the digital economy; the second promotes data interoperability and quality; and the third, issued in 2021, establishes the guidelines and an operating model for OD governance, including ontology-supported data publishing.
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Siva Raja, P. M., and C. Sahaya Kingsley. "Energy Efficient Geo-distributed Data Center Resizing Markov Chain Model." In Lecture Notes in Networks and Systems. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-0980-0_4.
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Lin, Chuangwei, Bowen Liu, Wei Zhou, Yueyue Xu, Xuyun Zhang, and Wanchun Dou. "A Low-Latency Metadata Service for Geo-Distributed File Systems." In Web Information Systems Engineering – WISE 2021. Springer International Publishing, 2021. http://dx.doi.org/10.1007/978-3-030-90888-1_7.
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Teyeb, Hana, Nejib Ben Hadj-Alouane, and Samir Tata. "Network-Aware Stochastic Virtual Machine Placement in Geo-Distributed Data Centers." In On the Move to Meaningful Internet Systems. OTM 2017 Conferences. Springer International Publishing, 2017. http://dx.doi.org/10.1007/978-3-319-69462-7_3.
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Rohini, T. V., and M. V. Ramakrishna. "Cost Optimization for Dynamic Data Migration and Re-placement with Load-Balancing in Geo-Distributed Systems." In Lecture Notes in Electrical Engineering. Springer Singapore, 2021. http://dx.doi.org/10.1007/978-981-16-3690-5_143.
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Sikder, Iftikhar U., and Aryya Gangopadhyay. "Distributed Data Warehouse for Geo-spatial Services." In ERP & Data Warehousing in Organizations. IGI Global, 2003. http://dx.doi.org/10.4018/978-1-93177-749-0.ch008.
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This chapter introduces the research issues on spatial decision-making in the context of distributed geo-spatial data warehouse. Spatial decision-making in a distributed environment involves access to data and models from heterogeneous sources and composing disparate services into a meaningful integration. The chapter reviews system integration and interoperability issues of spatial data and models in a distributed computing environment. We present a prototype system to illustrate the collaborative access to data and as a model for supporting spatial decision-making.
Actas de conferencias sobre el tema "Geo-distributed system"
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Segura, Marc, Vianney Rancurel, Vinh Tao, and Marc Shapiro. "Scality's experience with a geo-distributed file system." In the Posters & Demos Session. ACM Press, 2014. http://dx.doi.org/10.1145/2678508.2678524.
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Oh, Kwangsung, Abhishek Chandra, and Jon Weissman. "A Network Cost-aware Geo-distributed Data Analytics System." In 2020 20th IEEE/ACM International Symposium on Cluster, Cloud and Internet Computing (CCGRID). IEEE, 2020. http://dx.doi.org/10.1109/ccgrid49817.2020.00-28.
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Jieming Zhu, Zibin Zheng, Yangfan Zhou, and M. R. Lyu. "Scaling Service-Oriented Applications into Geo-distributed Clouds." In 2013 IEEE 7th International Symposium on Service Oriented System Engineering (SOSE 2013). IEEE, 2013. http://dx.doi.org/10.1109/sose.2013.56.
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Sumalatha, M. R., Pranab Batsa, Abhishek Sinha, and P. Shrinath. "Social media for disaster relief — Geo distributed social service system." In 2015 Seventh International Conference on Advanced Computing(ICoAC). IEEE, 2015. http://dx.doi.org/10.1109/icoac.2015.7562783.
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Maiyya, Sujaya, Ishtiyaque Ahmad, Divyakant Agrawal, and Amr El Abbadi. "Samya: A Geo-Distributed Data System for High Contention Aggregate Data." In 2021 IEEE 37th International Conference on Data Engineering (ICDE). IEEE, 2021. http://dx.doi.org/10.1109/icde51399.2021.00128.
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Li, Yan, Hong Zhang, Yong Wang, Xinran Liu, and Peng Zhang. "A Scheduling Framework for Periodic Tasks in Geo-Distributed Data Centers." In 2015 IEEE Symposium on Service-Oriented System Engineering (SOSE). IEEE, 2015. http://dx.doi.org/10.1109/sose.2015.29.
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Wang, Peng, Wenyu Liu, Ming Cheng, Zhaohao Ding, and Yi Wang. "Electricity and Carbon-aware Task Scheduling in Geo-distributed Internet Data Centers." In 2022 IEEE/IAS Industrial and Commercial Power System Asia (I&CPS Asia). IEEE, 2022. http://dx.doi.org/10.1109/icpsasia55496.2022.9949832.
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Ye, Guisen, and Feng Gao. "Joint Workload Scheduling Method in Geo-Distributed Data Centers Considering UPS Loss." In 2021 IEEE/IAS Industrial and Commercial Power System Asia (I&CPS Asia). IEEE, 2021. http://dx.doi.org/10.1109/icpsasia52756.2021.9621553.
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Wang, Haoyu, Haiying Shen, Zijian Li, and Shuhao Tian. "GeoCol: A Geo-distributed Cloud Storage System with Low Cost and Latency using Reinforcement Learning." In 2021 IEEE 41st International Conference on Distributed Computing Systems (ICDCS). IEEE, 2021. http://dx.doi.org/10.1109/icdcs51616.2021.00023.
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Wang, Haoyu, Haiying Shen, Zijian Li, and Shuhao Tian. "GeoCol: A Geo-distributed Cloud Storage System with Low Cost and Latency using Reinforcement Learning." In 2021 IEEE 41st International Conference on Distributed Computing Systems (ICDCS). IEEE, 2021. http://dx.doi.org/10.1109/icdcs51616.2021.00023.
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