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Modelo de gerenciamento para infra-estrutura de medições de desempenho em redes de computadores; Management model for measurement infrastructure in computer networks

Battisti, Gerson
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Tese de Doutorado Formato: application/pdf
Português
Relevância na Pesquisa
66.34%
A avaliação do comportamento das redes de computadores através de métricas de desempenho é útil para avaliação de protocolos, para o aperfeiçoamento de aplicações, na escolha de conteúdo, entre outros. A obtenção destas métricas, porém, continua sendo uma tarefa complexa porque na maioria das vezes não se tem instrumentos adequados para tal. O desempenho de uma rede é fácil de ser obtido quando as conexões envolvidas estão limitadas a uma Intranet, pois os administradores têm acesso irrestrito a todos os equipamentos envolvidos. Por outro lado, quando os equipamentos pertencerem a domínios administrativos diferentes, a avaliação de desempenho passa a ser uma tarefa difícil de ser efetuada. As infra-estruturas de medição de desempenho foram propostas como uma forma de dotar as redes de computadores com instrumentos que facilitem a mensuração do desempenho. Uma infra-estrutura de medição de desempenho é um conjunto de equipamentos, espalhados por diversas redes, designados para interagirem uns com os outros quantificando o desempenho dos enlaces entre eles. As vantagens da utilização de infra-estruturas de medição de desempenho são claras, porém a sua utilização em larga escala ainda é problemática. Isso ocorre por problemas de escalabilidade e da inabilidade de gerenciamento dos equipamentos que compõem a infra-estrutura...

An infrastructure for accurate characterization of single-event transients in digital circuits☆

Savulimedu Veeravalli, Varadan; Polzer, Thomas; Schmid, Ulrich; Steininger, Andreas; Hofbauer, Michael; Schweiger, Kurt; Dietrich, Horst; Schneider-Hornstein, Kerstin; Zimmermann, Horst; Voss, Kay-Obbe; Merk, Bruno; Hajek, Michael
Fonte: IPC Science and Technology Press] Publicador: IPC Science and Technology Press]
Tipo: Artigo de Revista Científica
Publicado em /11/2013 Português
Relevância na Pesquisa
36.21%
We present the architecture and a detailed pre-fabrication analysis of a digital measurement ASIC facilitating long-term irradiation experiments of basic asynchronous circuits, which also demonstrates the suitability of the general approach for obtaining accurate radiation failure models developed in our FATAL project. Our ASIC design combines radiation targets like Muller C-elements and elastic pipelines as well as standard combinational gates and flip-flops with an elaborate on-chip measurement infrastructure. Major architectural challenges result from the fact that the latter must operate reliably under the same radiation conditions the target circuits are exposed to, without wasting precious die area for a rad-hard design. A measurement architecture based on multiple non-rad-hard counters is used, which we show to be resilient against double faults, as well as many triple and even higher-multiplicity faults. The design evaluation is done by means of comprehensive fault injection experiments, which are based on detailed Spice models of the target circuits in conjunction with a standard double-exponential current injection model for single-event transients (SET). To be as accurate as possible, the parameters of this current model have been aligned with results obtained from 3D device simulation models...

Infrastructure and Growth in South Africa : Direct and Indirect Productivity Impacts of 19 Infrastructure Measures

Fedderke, J. W.; Bogetic, Z.
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
36.12%
Empirical explorations of the growth and aggregate productivity impacts of infrastructure have been characterized by ambiguous (countervailing signs) results with little robustness. This paper, utilizing panel data for South African manufacturing over the 1970-2000 period, and a range of 19 infrastructure measures, explores the question of infrastructure endogeneity in output equations. The paper develops an instrumentation strategy generalizable to other contexts. Controlling for the possibility of endogeneity in the infrastructure measures renders the impact of infrastructure capital not only positive, but of economically meaningful magnitudes.

Infrastructure and Growth in South Africa: Direct and Indirect Productivity Impacts of 19 Infrastructure Measures

Fedderke, Johannes W.; Bogetić, Željko
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Português
Relevância na Pesquisa
36.21%
Empirical explorations of the growth and productivity impacts of infrastructure have been characterized by ambiguous (countervailing signs) results with little robustness. A number of explanations of the contradictory findings have been proposed. These range from the crowd-out of private by public sector investment, non-linearities generating the possibility of infrastructure overprovision, simultaneity between infrastructure provision and growth, and the possibility of multiple (hence indirect) channels of influence between infrastructure and productivity improvements. The authors explore these possibilities using panel data for South Africa over the 1970-2000 period, and a range of 19 infrastructure measures. Using a number of alternative measures of productivity, the prevalence of ambiguous (countervailing signs) results, with little systematic pattern is also shown to hold for their data set in estimations that include the infrastructure measures in simple growth frameworks. The authors demonstrate that controlling for potential endogeneity of infrastructure in estimation robustly eliminates virtually all evidence of ambiguous impacts of infrastructure, due for example to possible overinvestment in infrastructure. Controlling for the possibility of endogeneity in the infrastructure measures renders the impact of infrastructure capital not only positive...

Infrastructure, Growth, and Inequality : An Overview

Calderon, Cesar; Serven, Luis
Fonte: World Bank Group, Washington, DC Publicador: World Bank Group, Washington, DC
Português
Relevância na Pesquisa
36.22%
Academics and policy makers have long considered an adequate supply of infrastructure services to be essential for economic development. This paper reviews recent theoretical and empirical literature on the effects of infrastructure development on growth and income distribution. The theoretical literature has employed a variety of analytical settings regarding the drivers of income growth, the degree to which infrastructure represents a public or a private good, and the extent of market distortions, notably in capital markets. In turn, the empirical literature has used various econometric methodologies on time-series and cross-section macro and microeconomic data to test for the effects of infrastructure development. However, these empirical tests face challenging issues of measurement, identification, and heterogeneity. Overall, the literature finds positive effects of infrastructure development on income growth and, more tentatively, on distributive equity. Still, the precise mechanisms through which these effects accrue...

Transport Infrastructure and Welfare

Ali, Rubaba; Barra, Alvaro Federico; Berg, Claudia N.; Damania, Richard; Nash, John; Russ, Jason
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
Português
Relevância na Pesquisa
36.17%
Transport infrastructure is deemed to be central to development and consumes a large fraction of the development assistance envelope. Yet there is debate about the economic impact of road projects. This paper proposes an approach to assess the differential development impacts of alternative road construction and prioritize various proposals, using Nigeria as a case study. Recognizing that there is no perfect measure of economic well-being, a variety of outcome metrics are used, including crop revenue, livestock revenue, non-agricultural income, the probability of being multi-dimensionally poor, and local gross domestic product for Nigeria. Although the measure of transport is the most accurate possible, it is still endogenous because of the nonrandom placement of road infrastructure. This endogeneity is addressed using a seemingly novel instrumental variable termed the natural path: the time it would take to walk along the most logical route connecting two points without taking into account other, bias-causing economic benefits. Further...

Firm Productivity and Infrastructure Costs in East Africa

Iimi, Atsushi; Humphrey, Richard Martin; Melibaeva, Sevara
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
Português
Relevância na Pesquisa
36.2%
Infrastructure is an important driving force for economic growth. It reduces trade and transaction costs and stimulates the productivity of the economy. Africa has been lagging behind in the global manufacturing market. Among others, infrastructure is an important constraint in many African countries. Using firm-level data for East Africa, the paper reexamines the relationship between firm performance and infrastructure. It is shown that labor costs are by far the most important to stimulate firm production. Among the infrastructure sectors, electricity costs have the highest output elasticity, followed by transport costs. In addition, the paper shows that the quality of infrastructure is important to increase firm production. In particular, quality transport infrastructure seems to be essential. The paper also finds that agglomeration economies can reduce firm costs. The agglomeration elasticity is estimated at 0.03–0.04.

Firms’ Locational Choice and Infrastructure Development in Tanzania

Iimi, Atsushi; Humphreys, Richard Martin; Melibaeva, Sevara
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
Português
Relevância na Pesquisa
36.19%
Agglomeration economies are among the most important factors in increasing firm productivity. However, there is little evidence supportive of this in Africa. Using the firm registry database in Tanzania, this paper examines a new application of the logit approach with two empirical issues taken into account: spatial autocorrelation and endogeneity of infrastructure placement. The paper finds significant agglomeration economies. It is also found that firms are more likely to be located where local connectivity and access to markets are good. The paper finds that dealing with infrastructure endogeneity and spatial autocorrelation in the empirical model is important. According to the exogeneity test, infrastructure variables are likely endogenous. The spatial autoregressive term is significant. As expected, therefore, there are positive externalities of firm location choice around the neighboring areas.

The Cost of Road Infrastructure in Low and Middle Income Countries

Collier, Paul; Kirchberger, Martina; Söderbom, Måns
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Trabalho em Andamento
Português
Relevância na Pesquisa
36.15%
The connections between transport infrastructure and economic development have been extensively analyzed in previous research, but little is known about the cost of infrastructure investments in poor countries. This paper examines drivers of unit costs of construction and maintenance of transport infrastructure in low and middle income countries and documents that: (i) there is a large dispersion in unit costs for comparable road work activities; (ii) after accounting for environmental drivers of costs, residual unit costs are significantly higher in conflict countries; (iii) there is evidence that costs are higher in countries with higher levels of corruption; (iv) these effects are robust to controlling for a country’s public investment capacity and business environment. Our findings have implications for governments aiming to increase connectivity in poor countries.

Essays on transportation infrastructure, urbanisation and economic growth: evidence from China.

He, Xiaobo
Fonte: Universidade de Adelaide Publicador: Universidade de Adelaide
Tipo: Tese de Doutorado
Publicado em //2013 Português
Relevância na Pesquisa
36.18%
China’s spectacular economic growth during the reform era from 1978 to 2008 has captivated much attention both in academia and in the policy arena. This thesis looks at this period of Chinese economic reforms and the consequences for China’s economic growth, urbanisation, and income inequality, in which transportation infrastructure plays a pivotal role. Among many contributors to the economic growth in China, as measured by GDP per capita growth, recent studies shed light on the importance of transportation infrastructure. Therefore, a comprehensive understanding of the function of transportation infrastructure in the context of China and an accurate quantification of its contribution are desired. Accompanying the GDP per capita growth, China also experienced a rapid process of urbanisation during 1978–2008. However, whether the GDP per capita growth causes urbanisation is not yet clear. After the accession to the WTO in 2001, China became an important player in world trade. For example, China’s exports increased from USD 0.27 trillion in 2001 to USD 1.43 trillion in 2008, which has resulted in massive income growth nation-wide. However, the income has been unequally distributed among wage earners. Since urban wage earners are more likely to work in exporting sectors...

Walk Urban : Demand, Constraints, and Measurement of the Urban Pedestrian Environment

Montgomery, Brittany; Roberts, Peter
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
Português
Relevância na Pesquisa
36.1%
"Overall support for the pedestrian environment," or walk ability, has grown increasingly important as the world urbanizes and motorized modes threaten to displace or constrain travel on foot. This concern encompasses virtually every aspect of the pedestrian experience. Walk ability takes into account the quality of pedestrian facilities, roadway conditions, land use patterns, community support, security, and comfort for walking (Litman). Each of these facets of the pedestrian environment impacts the use of walking as a primary mode of transport. The complexity of the urban pedestrian environment naturally lends itself to micro-level analysis to locate the need for improvements; however, to gain an overview of a city, it is necessary to develop macro-level indicators that can identify the general state of the pedestrian environment. While these indicators cannot diagnose all walk ability problems, they can give a sense of how one urban area compares to another in similar circumstances and they have the potential for becoming an influential aspect of World Bank urban infrastructure diagnosis. Urban Transport indicators are being reviewed as one component of the current Transport Results Initiative which is led by the World Bank's central Transport Unit.

Infrastructure and Economic Development in Sub-Saharan Africa; Journal of African Economies

Calderon, Cesar; Serven, Luis
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Journal Article; Journal Article
Português
Relevância na Pesquisa
36.26%
An adequate supply of infrastructure services has long been viewed by both academics and policy makers as a key ingredient for economic development. Sub-Saharan Africa ranks consistently at the bottom of all developing regions in terms of infrastructure performance, and an increasing number of observers point to deficient infrastructure as a major obstacle for growth and poverty reduction across the region. This paper offers an empirical assessment of the impact of infrastructure development on growth and inequality, with a focus on Sub-Saharan Africa. The paper uses a comparative cross-regional perspective to place Africa's experience in the international context. Drawing from an updated data set of infrastructure quantity and quality indicators covering more than 100 countries and spanning the years 1960-2005, the paper estimates empirical growth and inequality equations including a standard set of control variables augmented by infrastructure quantity and quality measures, and controlling for the potential endogeneity of the latter. The estimates illustrate the potential contribution of infrastructure development to growth and equity across Africa.

Infrastructure Coverage and the Poor : The Global Perspective

Komives, Kristin; Whittington, Dale; Wu, Xun
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
Português
Relevância na Pesquisa
36.1%
The authors use the World Bank's Living Standards Measurement Study (LSMS) surveys from 15 countries (covering more than 55,500 households) to examine the relationship between infrastructure coverage and household income. The results show that throughout the world all income groups have much higher levels of coverage for electricity than for other formal infrastructure services (in-house piped water service, sewerage service, and private telephone service). In many countries most households in urban areas now have electricity service. As monthly household incomes increase from $100 to $250, coverage of all these infrastructure services rises, but at different rates. The findings confirm that the very poor rarely have these infrastructure services - with exceptions. The very poor often do have electricity if they live in urban areas. The very poor in Eastern Europe and Central Asia have much higher levels of coverage than those elsewhere in the world; they often have electricity, water, sewer, and telephone services. The results also suggest that if the poor gain access to services in their communities...

Toward Better Infrastructure : Conditions, Constraints, and Opportunities in Financing Public-Private Partnerships in Select African Countries

Shendy, Riham; Kaplan, Zachary; Mousley, Peter
Fonte: World Bank Publicador: World Bank
Tipo: Publications & Research :: Publication; Publications & Research :: Publication
Português
Relevância na Pesquisa
36.19%
Examining innovative ways to address Africa's infrastructure deficit is at the heart of this analysis. Africa's infrastructure stock and quality is among the least developed in the world, a challenge that significantly hinders economic development. The study is structured around the most inhibiting constraints to developing PPPs, as shared by all six countries. Section one provides a brief background of the infrastructure needs in the sample countries and outlines the current scope of Public-Private Partnership (PPP) transactions; section two examines the sources of financing for PPPs domestic and foreign with a particular focus on domestic sources; section three explores the supporting legislative, regulatory, and institutional environment for PPPs; section four addresses issues connected with the importance of developing a sound pipeline of PPP projects; and section five tackles the importance of managing the increased government fiscal commitments that are commonly coupled with PPPs. Section six outlines medium-term options for PPP financing. Finally...

A Trio of Perspectives on Corruption : Bias, Speed Money and “Grand Theft Infrastructure”

Kenny, Charles; Klein, Michael; Sztajerowska, Monika
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
Português
Relevância na Pesquisa
36.14%
A number of recent survey articles express hope that new data from enterprise surveys would shed new light on corruption complementing the corruption perception index by Transparency International. The paper explores this using the World Bank's Enterprise Survey data globally and not just the data on Eastern Europe and Central Asia that have been used before. The authors find that in general the Enterprise Survey data provide aggregate views on corruption that are similar to the corruption perception index. However, massive differences exist for key countries, such as China and India. This suggests that idiosyncratic, country-specific biases are at work in one or both data sources. The authors use the Enterprise Survey data and relate them to measures of bureaucratic complexity from the World Bank's Doing Business data, finding that more red tape is associated with higher corruption. The data are also consistent with the view that bribe payments reduce the burden of red tape. Finally, the paper looks at corruption in infrastructure. It has been suggested that the natural monopoly characteristics of infrastructure provide the lever to extract bribes. However...

Spending on Public Infrastructure : A Practitioner's Guide

Briceno-Garmendia, Cecilia; Sarkodie, Afua
Fonte: Banco Mundial Publicador: Banco Mundial
Tipo: Publications & Research :: Policy Research Working Paper
Português
Relevância na Pesquisa
36.2%
This paper provides a methodological tool to support the collection and preparation of standardized, comprehensive data regarding public spending on infrastructure services that can be rigorously compared across countries. Infrastructure is defined to cover six sectors: irrigation, energy (primarily power), transport, communication, wastewater management, and water supply. The guide is designed to provide a much richer and more complete measurement of infrastructure spending than the limited highly aggregated data currently available through the IMF Government Financial Statistics. Originally developed for Africa, the methodology is relevant and readily applicable to any developing country. With the aim of being as comprehensive as possible, the methodology covers central and sub-national government expenditures, non-budgetary vehicles (such as road funds), state-owned enterprises (SOEs), and public-private partnerships (PPPs). While the methodology focuses on collecting quantitative data on the level and composition of spending...

How Relevant Is Infrastructure to Growth in East Asia?

Seethepalli, Kalpana; Bramati, Maria Caterina; Veredas, David
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Policy Research Working Paper; Publications & Research
Português
Relevância na Pesquisa
36.33%
This paper seeks to shed some light on the extent to which infrastructure sub-sectors - energy, telecommunications, water supply, sanitation, and transport - contributed to growth in East Asia during 1985-2004. It also attempts to provide additional insights on whether the relationship between infrastructure and growth depends on five additional variables: the degree of private participation in infrastructure, the quality of governance, the extent of rural-urban inequality in access to infrastructure services, country income levels, as well as geography. The findings show that greater stocks of infrastructure were indeed associated with higher growth. However, a more nuanced look at the sensitivity of infrastructure impacts on the five additional variables yields different results, with some sectors supporting conventional expectations and others yielding mixed or counter-intuitive results. In particular, the telecom and sanitation sectors yield statistically significant results supporting the a priori hypotheses; electricity and water infrastructure provide mixed results; and road infrastructure consistently contradicts a priori expectations. The results are consistent with the widely-accepted idea in policy research that infrastructure plays an important role in promoting growth...

Transport Activity Measurement Toolkit for On-Road Vehicles : Practitioners' Guide

Rogers, John A.
Fonte: World Bank, Washington, DC Publicador: World Bank, Washington, DC
Tipo: Publications & Research :: Working Paper; Publications & Research
Português
Relevância na Pesquisa
36.17%
Although urbanization is frequently cited as a major cause of greenhouse gas and local air pollution emissions growth, it could be better understood as one of the crucial links between climate and development. Urbanization is a major driver of development, and once in cities, people tend to increase their mobility dramatically, driving an increase in greenhouse gas and other emissions from transport. The demand for transport is not limited only to urban environments. As each economy becomes richer, its demand for passenger and freight mobility increases. This increase in car usage coupled with a tendency to have a lower number of passengers per car, has been sufficient to offset the improvements gained in vehicle fuel efficiency. The increasing transport demand, if not accompanied by adequate growth in infrastructure and facilities, leads to rising congestion, time loss, and air quality deterioration that can stifle economic growth and quality of life. Finding the delicate balance of policy options to achieve long-term improvements in on-road transport and reduce the impact of its externalities is critical and needs to be tailored to each locale. This requires measurements both to design the interventions and evaluate their impacts. This transport activity measurement toolkit (TAMT) has been developed specifically to simplify this measurement process by providing standardized software...

Estimation of available bandwidth and measurement infrastructure for Russian segment of Internet

Platonov, A. P.; Sidelnikov, D. I.; Strizhov, M. V.; Sukhov, A. M.
Fonte: Universidade Cornell Publicador: Universidade Cornell
Tipo: Artigo de Revista Científica
Português
Relevância na Pesquisa
46.09%
In paper the method for estimation of available bandwidth is supposed which does not demand the advanced utilities. Our method is based on the measurement of network delay $D$ for packets of different sizes $W$. The simple expression for available bandwidth $B_{av} =(W_2-W_1)/(D_2-D_1)$ is substantiated. For the experimental testing the measurement infrastructure for Russian segment of Internet was installed in framework of RFBR grant 06-07-89074.; Comment: 8 pages, 4 figures, submitted to Telecommunication (www.nait.ru, in Russian)

A Levels-based Approach for Defining Software Measurement Architectures

Maretto,Ciro Xavier; Perini Barcellos,Monalessa
Fonte: CLEI Electronic Journal Publicador: CLEI Electronic Journal
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2014 Português
Relevância na Pesquisa
36.21%
During the execution of software projects, it is necessary to collect, store and analyze data to support project and organizational decisions. Software measurement is a fundamental practice for project management and process improvement. It is present in the main models and standards that address software process improvement, such as ISO/IEC 12207, CMMI and MR MPS.BR. In order to effectively perform software measurement, it is necessary an infrastructure to support data collection, storage and analysis. This infrastructure can be defined by means of an architecture, which describes the components necessary to support software measurement. In this paper we present the main results obtained from a systematic mapping study that investigated software measurement architectures and an approach proposed aiming to help organizations define software measurement architectures.