Página 1 dos resultados de 52 itens digitais encontrados em 0.033 segundos

Protocolos multicoordenados de acordo e o serviço de log; Multicoordinated agreement problems and the log service

Lasaro Jonas Camargos
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 12/12/2008 PT
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Problemas de acordo, como Consenso, Terminação Atômica e Difusão Atômica, são abstrações comuns em sistemas distribuídos. Eles ocorrem quando os componentes do sistema precisam concordar em reconfigurações, mudanças de estado ou em linhas de ação em geral. Nesta tese, investigamos estes problemas no contexto do ambiente e aplicações em que serão utilizados. O modelo geral é o assíncrono sujeito a quebras com possível posterior recuperação. Nossa meta é desenvolver protocolos que explorem esta informação contextual para prover maior disponibilidade, e que se mantenham corretos mesmo que algumas das prerrogativas do contexto tornem-se inválidas. Na primeira parte da tese, exploramos a seguinte propriedade: mensagens difundidas em pequenas redes tendem a ser entregues ordenada e confiavelmente. Nós fazemos três contribuições nesta parte da tese. A primeira é a transformação de algoritmos conhecidos para o modelo quebra-e-pára, que utilizam a propriedade de ordenação mencionada, em protocolos práticos. Isto é, protocolos que toleram perda de mensagens e recuperação após a quebra. Nossos protocolos garantem progresso na presença de falhas, contanto que mensagens sejam espontaneamente ordenadas freqüentemente. Na ausência de ordenação expontânea...

Proposta e validação de nova arquitetura de redes de data center; Proposal and Validation of New Architecture for Data Center Networks

Carlos Alberto Bráz Macapuna
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 29/04/2011 PT
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Assim como as grades computacionais, os centros de dados em nuvem são estruturas de processamento de informações com requisitos de rede bastante exigentes. Esta dissertação contribui para os esforços em redesenhar a arquitetura de centro de dados de próxima geração, propondo um serviço eficaz de encaminhamento de pacotes, que explora a disponibilidade de switches programáveis com base na API OpenFlow. Desta forma, a dissertação descreve e avalia experimentalmente uma nova arquitetura de redes de centro de dados que implementa dois serviços distribuídos e resilientes a falhas que fornecem as informações de diretório e topologia necessárias para codificar aleatoriamente rotas na origem usando filtros de Bloom no cabeçalho dos pacotes. Ao implantar um exército de gerenciadores de Rack atuando como controladores OpenFlow, a arquitetura proposta denominada Switching with in-packet Bloom filters (SiBF) promete escalabilidade, desempenho e tolerância a falhas. O trabalho ainda defende a ideia que o encaminhamento de pacotes pode tornar-se um serviço interno na nuvem e que a sua implementação pode aproveitar as melhores práticas das aplicações em nuvem como, por exemplo, os sistemas de armazenamento distribuído do tipo par

Modeling, characterization, and optimization of web server power in data centers = : Modelagem, caracterização e otimização de potência em centro de dados; Modelagem, caracterização e otimização de potência em centro de dados

Leonardo de Paula Rosa Piga
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 08/11/2013 PT
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Para acompanhar uma demanda crescente pelos recursos computacionais, empresas de TI precisaram construir instalações que comportam centenas de milhares de computadores chamadas centro de dados. Este ambiente é altamente dependente de energia elétrica, um recurso que é cada vez mais caro e escasso. Neste contexto, esta tese apresenta uma abordagem para otimizar potência e desempenho em centro de dados Web. Para isto, apresentamos uma infraestrutura para medir a potência dissipada por computadores de prateleiras, desenvolvemos modelos empíricos que estimam a potência de servidores Web e, por fim, implementamos uma de nossas heurísticas de otimização de potência global em um aglomerado de nós de processamento chamado AMD SeaMicro SM15k. A infraestrutura de medição de potência é composta por: uma placa personalizada, que é capaz de medir potência e é instalada em computadores de prateleira; um conversor de dados analógico/digital que amostra os valores de potência; e um software controlador. Mostramos uma nova metodologia para o desenvolvimento de modelos de potência para servidores Web que diminuem a quantidade de parâmetros dos modelos e reduzem as relações não lineares entre medidas de desempenho e potência do sistema. Avaliamos a nossa metodologia em dois servidores Web...

Uma arquitetura para aprovisionamento de redes virtuais definidas por software em redes de data center; An architecture for virtual networks defined by software embedding in data center networks

Raphael Vicente Rosa
Fonte: Biblioteca Digital da Unicamp Publicador: Biblioteca Digital da Unicamp
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 05/06/2014 PT
Relevância na Pesquisa
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Atualmente provedores de infraestrutura (Infrastructure Providers - InPs) alocam recursos virtualizados, computacionais e de rede, de seus data centers para provedores de serviços na forma de data centers virtuais (Virtual Data Centers - VDCs). Almejando maximizar seus lucros e usar de forma eficiente os recursos de seus data centers, InPs lidam com o problema de otimizar a alocação de múltiplos VDCs. Mesmo que a alocação de máquinas virtuais em servidores seja feita de maneira otimizada por diversas técnicas e algoritmos já existentes, aplicações de computação em nuvem ainda tem o desempenho prejudicado pelo gargalo do subaproveitamento de recursos de rede, explicitamente definidos por limitações de largura de banda e latência. Baseado no paradigma de Redes Definidas por Software, nós aplicamos o modelo de rede como serviço (Network-as-a-Service - NaaS) para construir uma arquitetura de data center bem definida para dar suporte ao problema de aprovisionamento de redes virtuais em data centers. Construímos serviços sobre o plano de controle da plataforma RouteFlow os quais tratam a alocação de redes virtuais de data center otimizando a utilização de recursos da infraestrutura de rede. O algoritmo proposto neste trabalho realiza a tarefa de alocação de redes virtuais...

BASIS: uma Arquitetura de Big Data para Smart Cities; BASIS: a Big Data Architecture for Smart Cities

Costa, Carlos Filipe Machado da Silva
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Trabalho de Conclusão de Curso
Publicado em //2015 POR
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Dissertação de mestrado integrado em Gestão de Sistemas de Informação; No mundo atual, os centros urbanos são a principal escolha para habitação. Cidadãos comportam-se como consumidores de serviços, esperando o desempenho adequado por parte dos órgãos gestores das cidades, independentemente das restrições vividas. Com este fenómeno advêm desafios de sustentabilidade económica, social e ambiental. É expectável que as cidades virem o seu foco para o cidadão e o enquadrem num governo participativo. Emerge assim o conceito de Smart City, onde a dinâmica humana atual assenta no uso intensivo da Internet of Things (IoT), em que vários dispositivos se encontram permanentemente conectados, gerando vastas quantidades de dados, nos mais variados formatos. As Smart Cities passam a ser vistas como uma fonte incessável de Big Data e um potencial campo de aplicação para as tecnologias de armazenamento e processamento deste emergente tipo de dados, definido sobretudo pelo volume, variedade e velocidade. Nesta dissertação propõe-se uma arquitetura de Big Data para Smart Cities (BASIS), cujo contributo foi suportado pela realização de um adequado enquadramento conceptual e tecnológico, onde são estudados os conceitos envolvidos nesta dissertação...

The Offshore Services Value Chain : Developing Countries and the Crisis

Gereffi, Gary; Fernandez-Stark, Karina
Fonte: Banco Mundial Publicador: Banco Mundial
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This paper analyzes the recent evolution and impact of the global economic crisis on the offshore services industry. Using a global value chains framework, the authors classify the offshore services sector in a comprehensive set of general and industry-specific activities that correspond to different segments and stages in the value-adding process for services. Through an analysis of the impact of the economic crisis on the industry, a small decline in demand was found; however this did not cause any structural changes in the market. The crisis has created two opposing effects: general contraction of demand by existing customers due to the recession; and, at the same time, a substitution effect by which new services are being moved from developed countries to emerging economies in search of cost reduction. The paper concludes that the offshore services industry will continue to offer growth opportunities for developing countries not only among existing market players, but also a range of new countries. The industry has the potential to become an important source for employment and economic growth around the globe.

Sustainable Telecenters : A Guide for Government Policy

Wellenius, Bjorn
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
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For at least a decade, governments and non-profit organizations, often supported by bilateral aid, have experimented with tele-centers as means to extend access to computers, the Internet, and other information, and communication services to rural, and low-income urban areas of developing countries. Results have been mixed. This note proposes a guide for government policy on tele-centers conceived as private businesses - though with development functions - that are commercially sustainable beyond initial public support.

A summary of the foundation development program.

Naval Postgraduate School (U.S.)
Fonte: Monterey, California. Naval Postgraduate School Publicador: Monterey, California. Naval Postgraduate School
Tipo: Relatório
EN_US
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The principal thrust of the exploratory development program at the Naval Postgraduate School (NPS) stems from the School's mission: To conduct and direct advanced education of commissioned officers, and to provide such other technical and professional instruction as may be prescribed to meet the needs of the Naval Service; and in support of the foregoing to foster and encourage a program of research in order to sustain academic excellence.; Prepared for: Chief of Naval Development Washington, D. C. 20360; http://archive.org/details/summaryoffoundat78002nava

Delay-Sensitive Service Request Scheduling for Cloud Computing

Liu, Shuo
Fonte: FIU Digital Commons Publicador: FIU Digital Commons
Tipo: Artigo de Revista Científica Formato: application/pdf
Relevância na Pesquisa
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Cloud computing realizes the long-held dream of converting computing capability into a type of utility. It has the potential to fundamentally change the landscape of the IT industry and our way of life. However, as cloud computing expanding substantially in both scale and scope, ensuring its sustainable growth is a critical problem. Service providers have long been suffering from high operational costs. Especially the costs associated with the skyrocketing power consumption of large data centers. In the meantime, while efficient power/energy utilization is indispensable for the sustainable growth of cloud computing, service providers must also satisfy a user's quality of service (QoS) requirements. This problem becomes even more challenging considering the increasingly stringent power/energy and QoS constraints, as well as other factors such as the highly dynamic, heterogeneous, and distributed nature of the computing infrastructures, etc. In this dissertation, we study the problem of delay-sensitive cloud service scheduling for the sustainable development of cloud computing. We first focus our research on the development of scheduling methods for delay-sensitive cloud services on a single server with the goal of maximizing a service provider's profit. We then extend our study to scheduling cloud services in distributed environments. In particular...

ICT Solutions for Energy Efficiency

Youngman, Richard
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Economic & Sector Work :: Energy Study; Economic & Sector Work
ENGLISH; EN_US
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The report is focused on showing a wide range and variety of ways in which Information and Communication Technologies (ICT) solutions could play a transformative role, and so the bulk of the report provides case studies of actual examples of ICT solutions already developed and in action to enable energy efficiency in three particular areas, namely, smart logistics, smart grid/smart metering, and smart buildings. Ultimately, in line with the WBG's charter, this study is concerned with the question of how ICT can play a transformative role in developing countries'climate-smart future. However, as the World Development Report 2010 recognized, this is bound to start in higher-income countries, which have the incentives (being high-energy and high-cost users), the technical know-how and the resources to innovate and implement pioneering solutions to cut their costs and their carbon emissions. Some such solutions will have applicability to the developing world; a minority right away, more year by year as technology is proven and efficiencies of scale kick in. The report concludes with some thoughts...

Trade in Information and Communication Services : Opportunities for East and Southern Africa

Telecommunications Management Group, Inc.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
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This following report is divided into four chapters, with chapter one containing the introduction. Chapter two reviews the state of ICT-competitiveness in the case study countries, by looking at infrastructure, the legal and regulatory situation, the business environment, and human resources. Chapter three examines the benefits of ICT for the overall economy as well as for facilitating traditional trade and participating in emerging ICT-enabled services trade. It analyzes the case study countries' potential for becoming players in ICT-enabled services. Finally, chapter four identifies the case study countries existing WTO ICT-related commitments, pointing out what changes are necessary to make deeper commitments and hence strengthen credibility as reliable trading partners.

Republic of Tunisia : Information and Communications Technology Contribution to Growth and Employment Generation, Volume 1. Policy Note

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
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This policy note is the first of two volumes, drafted in conjunction with a more detailed technical report. It was prepared in response to a request by the Government of Tunisia for Bank assistance to formulate an ICT development strategy, in accordance with the targets set in the Government of Tunisia's 10th development plan. The policy note highlights current constraints to ICT sector development and proposes measures to eliminate them. It should be read in conjunction with the broader strategy report (volume two: technical report), which contains complementary data and technical information. The Government objectives were conveyed to the World Bank team in May 2001. The strategy is aimed at bolstering the country's emerging ICT sector and maximizing its ability to compete in local, regional, and global markets. In this context, the major objectives of the ICT strategy are to: (a) maximize the ICT contribution to growth and employment generation; (b) position Tunisia in the global ICT market; and (c) integrate ICT into the Tunisian economy. Indirect issues of the ICT impact on productivity and competitiveness are marginally treated in this note. The report compares the state of ICT development in Tunisia that of other economies...

Czech Republic : Report on Vision and Strategy for an Integrated Revenue Administration

World Bank
Fonte: World Bank Publicador: World Bank
Tipo: Economic & Sector Work :: Other Poverty Study
ENGLISH
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This report is a result of the mission of the World Bank to the Czech Republic during November 17 to 27, 2008 for providing advisory service to the Government of the Czech Republic for the design and development of a modern, integrated revenue authority. Earlier, between February and April 2008, a World Bank mission had reviewed the draft merger plan prepared by the Ministry of Finance of the Czech Republic in January 2008 and examined the key issues for the merger of tax and customs administrations and the integration of the collection, enforcement and audit functions of social contributions. The preliminary findings of the World Bank are contained in the 'report on an integrated revenue administration' in two volumes which was disseminated in June 2008. This mission in November 2008 is the first in a series of missions over the next eighteen months for providing the advisory services as requested to the Government of the Czech Republic. During this first mission, the Bank has worked with the Czech counterparts to develop for the new Jednotni Inkasni Misto (JIM): (i) an integrated vision and key concepts (ii) major objectives and key elements of reform; (iii) a comprehensive strategy for reform of the organizational structure...

Connecting to Work : How Information and Communication Technologies Could Help Expand Employment Opportunities

Raja, Siddhartha; Imaizumi, Saori; Kelly, Tim; Narimatsu, Junko; Paradi-Guilford, Cecilia
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
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Information and communication technology (ICT) has grown as a sector and now employs millions of people worldwide. The proliferation of ICTs has also helped digitize how people find and do work. The world will need to create over 600 million jobs by 2030 for unemployment to remain at current levels. ICT-enabled employment may help address some of this problem both by creating jobs in the ICT sector and by helping to make labor markets more inclusive, innovative, flexible, and transparent. What can governments do to prepare for these changes and maximize employment opportunities? This paper is a first step in an effort by the World Bank to understand how ICTs are shaping, changing, and transforming labor markets. It explores how governments and other stakeholders might respond to leverage the growth of ICTs to help increase employment opportunities. This paper is structured as follows: section 1 serves as an introduction; section 2 defines the scope, focusing on the types of employment opportunities due to ICT as a sector and as a tool; section 3 considers the impact of the ICT sector on software programming...

A Social Development Saga : India Uttar Pradesh Basic Education and India District Primary Education Projects

Kuehnast, Kathleen
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Brief; Publications & Research
ENGLISH
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The Uttar Pradesh (UP) Basic Education Pilot Project and the national India District Primary Education Project exemplify good social development practices. The pilot project in UP to assist girls to achieve better education proved so successful that it was scaled up to a national project. The guiding principle of both projects is to improve education by building capacity at the community level. preparation. Surveys and focus group discussions identified a wide-range of educational issues at the village level. Problems ranged from caste discrimination to debate on the language of instruction to the impact of weather on educational opportunities. In some villages, girls were not attending school because of their responsibility to care for younger siblings. In other places, the issue was girls' safety. Lessons learned included the following: 1) Community support for education is a central element of a successful school development program. 2) Community implementation is a cost-effective way to achieve large-scale school construction. 3) Block Resource Centers and Cluster Resource Centers can serve as effective mechanisms to provide recurrent in-service training and school-based professional support for teachers. 4) Improving the quality of education and strengthening institutional capacity are long-term processes. 5) Micro-planning is necessary to assess the need for new schools and additional classrooms and teachers.

Mongolia : Development Impacts of Solar-Powered Electricity Services

World Bank
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
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Mongolia is a vast landlocked country with a relatively small population. Other than those living in the capital city and a few urban centers, the rest of its citizens (about 35 percent or one million people) are geographically disbursed throughout the rural countryside. Among them about three quarters are nomadic herders living in portable tents (gers). Given the immense logistical and climatic challenges, rural electrification was largely undeveloped until the Government launched the National 100,000 Solar Ger Electrification Program in 1999. The World Bank-assisted Renewable Energy and Rural Electricity Access Project (REAP) was conceived in 2006 to help the Government revitalize the 100k Program and remove other barriers to rural electrification. The ultimate objective of the project was to increase electricity access and improve the reliability of services in off-grid soum centers and amongst the herder population. The main portion of this report is divided into two chapters (Chapters 2-3). Chapter 2 is a brief description of the two beneficiary surveys carried out after REAP was completed. It includes the methodologies used...

Building Results Frameworks for Safety Nets Projects

Rubio, Gloria M.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
ENGLISH; EN_US
Relevância na Pesquisa
35.85%
Results chains are useful tools to clarify safety nets programs' objectives, verify the program internal logic, and guide the selection of indicators. Although the recent trend has been to focus mostly on outcome indicators, indicators are needed at all levels of the results chain to better understand program performance. Ideally, safety nets performance monitoring systems should build upon reliable program records and be complemented with a combination of tailor?made data sources and national surveys. The latter should be considered not only for monitoring purposes but within a program evaluation agenda. In any case, it is very important that adequate resources and technical assistance are channeled to strengthen institutional capacity for safety nets results-based management.

Virtualización de Centros de Cómputo en universidades privadas de Medellín

Giraldo Raigoza, Andrés; Gómez Toro, Juan Esteban
Fonte: Universidad EAFIT; Ingeniería de Sistemas; Escuela de Ingeniería. Departamento de Ingeniería de Sistemas Publicador: Universidad EAFIT; Ingeniería de Sistemas; Escuela de Ingeniería. Departamento de Ingeniería de Sistemas
Tipo: bachelorThesis; Trabajo de grado; acceptedVersion
SPA
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Inter-Cloud Data Security Strategies

Sanyal, Sugata; Iyer, Parthasarathy P.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Publicado em 06/03/2013
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25.84%
Cloud computing is a complex infrastructure of software, hardware, processing, and storage that is available as a service. Cloud computing offers immediate access to large numbers of the world's most sophisticated supercomputers and their corresponding processing power, interconnected at various locations around the world, proffering speed in the tens of trillions of computations per second. Information in databases and software scattered around the Internet. There are many service providers in the internet, we can call each service as a cloud, each cloud service will exchange data with other cloud, so when the data is exchanged between the clouds, there exist the problem of security. Security is an important issue for cloud computing, both in terms of legal compliance and user trust, and needs to be considered at every phase of design. In contrast to traditional solutions, where the IT services are under proper physical, logical and personnel controls, Cloud Computing moves the application software and databases to the large data centers, where the management of the data and services may not be trustworthy. This unique attribute, however, poses many new security challenges. Cloud computing seems to offer some incredible benefits for communicators.; Comment: 5 pages...

High Volume Computing: Identifying and Characterizing Throughput Oriented Workloads in Data Centers

Zhan, Jianfeng; Zhang, Lixin; Sun, Ninghui; Wang, Lei; Jia, Zhen; Luo, Chunjie
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Relevância na Pesquisa
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For the first time, this paper systematically identifies three categories of throughput oriented workloads in data centers: services, data processing applications, and interactive real-time applications, whose targets are to increase the volume of throughput in terms of processed requests or data, or supported maximum number of simultaneous subscribers, respectively, and we coin a new term high volume computing (in short HVC) to describe those workloads and data center computer systems designed for them. We characterize and compare HVC with other computing paradigms, e.g., high throughput computing, warehouse-scale computing, and cloud computing, in terms of levels, workloads, metrics, coupling degree, data scales, and number of jobs or service instances. We also preliminarily report our ongoing work on the metrics and benchmarks for HVC systems, which is the foundation of designing innovative data center computer systems for HVC workloads.; Comment: 10 pages