975 resultados para F-statistics
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The SETAS pilot project was carried out by the ECLAC Transport Unit, between October 1999 and May 2000 to assess the feasibility of constructing a transport statistics information system for South America. As this would entail a major effort to establish common statistical procedures and criteria between countries, the pilot project attempted to assess the potential of using informatics techniques for standardizing a significant set of regional transport statistics variables.The pilot phase involved specialized transport statistics institutes from Bolivia, Brazil and Chile — the countries chosen to participate in the initial stage of the project. There was also participation by staff members from the Latin American Integration Association (LAIA), and from the ECLAC Statistics and Economic Projections Division, the Electronic Information Centre and the Transport Unit of the Natural Resources and Infrastructure Division.This edition of the FAL Bulletin explains on the components of the SETAS pilot project and the results obtained.
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Statistical organizations of the Caribbean countries continue to face serious challenges posed by the increased demand for more relevant, accurate and timely statistical data. Tangible progress has been made in delivering key products in the area of economic statistics. The central banks of the subregion have assisted greatly in this respect. However, even in this branch of statistics there are still several glaring gaps. The situation is even worse in other areas of statistics including social and environmental statistics. Even though all countries of the subregion have committed to the Millennium Development Goals (MDGs) as well as to other internationally agreed development goals serious challenges remain with respect to the compilation of the agreed indicators to assist in assessing progress towards the goals. It is acknowledged that appreciable assistance has been provided by the various donor agencies to develop statistical competence. This assistance has translated into the many gains that have been made. However, the national statistical organizations require much more help if they are to reach the plateau of self reliance in the production of the necessary statistical services. The governments of the subregion have also committed to invest more in statistical development and in promoting a statistics culture in the Caribbean. The training institutions of the subregion have also started to address this urgent need by broadening and deepening their teaching curricula. Funding support is urgently required to develop the appropriate cadre of statistical professionals to deliver the required outputs. However, this training must be continuous and must be sustained over an appropriate period since the current turnover of trained staff is high. This programme of training will need to be intensive for a period of at least five years after which it may be reduced. The modalities of training will also have to be more focused and in addition to formal training at educational institutions there is much room for on-the-job training, group training at the national level and much more south-south capacity building. There is also an urgent need to strengthen cooperation and collaboration among the donor community in the delivery of assistance for statistical development. Several development agencies with very good intentions are currently operating in the Caribbean. There is a danger however, that efforts can be duplicated if agencies do not collaborate adequately. Development agencies therefore need to consult with each other much more and share there development agenda more freely if duplication is to be averted. Moreover, the pooling of resources can surely maximize the benefits to the countries of the subregion.
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The unavailability of data to inform policy planning and formulation has been repeatedly cited as the main challenge to economic and social progress in the Caribbean. Furthermore, even in instances when data is produced, broader gaps exist between its production and eventual use for evidence-based policy formulation. Owing to those challenges, this report explores the use of databases of social and gender statistics in the development of policies and programmes in the Caribbean subregion. The report offers a general appraisal of databases against two main considerations: (i) maximizing the use of existing databases in relevant policies and programmes; and (ii) bridging the gaps in data availability of relevant statistical databases and their analyses. The assessment entailed an inventory of social and gender databases maintained by data producers in the region and analysis of the extent to which the databases are used for policy formulation. To that end, a literature search as well as consultations with a number of knowledgeable persons active in the field of statistics and data provision was conducted. Based on the review, a set of recommendations were produced to improve current practices within the region with respect evidence based policy formulation.
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The data revolution for sustainable development has triggered interest in the use of big data for official statistics such that theUnited Nations Economic and Social Council considers it to be almost an obligation for statistical organizations to explore big data. Big data has been promoted as a more timely and cheaper alternative to traditional sources of official data, and one that offers great potential for monitoring the sustainable development goals. However, privacy concerns, technology and capacity remain significant obstacles to the use of big data. This study makes a case for incorporating big data in official statitics in the Caribbean by highlight the opportunities that big data provides for the subregion, while suggesting ways to manage the challenges. It serves as a starting point for further discussions on the many facets of big data and provides an initial platform upon which a Caribbean big data strategy could be built.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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With the widespread proliferation of computers, many human activities entail the use of automatic image analysis. The basic features used for image analysis include color, texture, and shape. In this paper, we propose a new shape description method, called Hough Transform Statistics (HTS), which uses statistics from the Hough space to characterize the shape of objects or regions in digital images. A modified version of this method, called Hough Transform Statistics neighborhood (HTSn), is also presented. Experiments carried out on three popular public image databases showed that the HTS and HTSn descriptors are robust, since they presented precision-recall results much better than several other well-known shape description methods. When compared to Beam Angle Statistics (BAS) method, a shape description method that inspired their development, both the HTS and the HTSn methods presented inferior results regarding the precision-recall criterion, but superior results in the processing time and multiscale separability criteria. The linear complexity of the HTS and the HTSn algorithms, in contrast to BAS, make them more appropriate for shape analysis in high-resolution image retrieval tasks when very large databases are used, which are very common nowadays. (C) 2014 Elsevier Inc. All rights reserved.
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It has been recently shown numerically that the transition from integrability to chaos in quantum systems and the corresponding spectral fluctuations are characterized by 1/f(alpha) noise with 1 <= alpha <= 2. The system of interacting trapped bosons is inhomogeneous and complex. The presence of an external harmonic trap makes it more interesting as, in the atomic trap, the bosons occupy partly degenerate single-particle states. Earlier theoretical and experimental results show that at zero temperature the low-lying levels are of a collective nature and high-lying excitations are of a single-particle nature. We observe that for few bosons, the P(s) distribution shows the Shnirelman peak, which exhibits a large number of quasidegenerate states. For a large number of bosons the low-lying levels are strongly affected by the interatomic interaction, and the corresponding level fluctuation shows a transition to a Wigner distribution with an increase in particle number. It does not follow Gaussian orthogonal ensemble random matrix predictions. For high-lying levels we observe the uncorrelated Poisson distribution. Thus it may be a very realistic system to prove that 1/f(alpha) noise is ubiquitous in nature.
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Statistics is a required course in virtually all undergraduate programs in Brazilian universities. In addition, undergraduate programs in Statistics are offered in many public universities. However, despite the importance of this science, there are no systematic studies in the national literature regarding the characterization of the faculty staff, which is responsible for the teaching of statistics in the country. In this context, this paper presents a description of the faculty members of undergraduate courses in Statistics. This description was based on a descriptive sample, related to aspects of their education and scientific production. A prediction of future demand for PhDs in Statistics to fill the vacancies is also provided based on the retirement of faculty members in undergraduate courses in Statistics in the country.
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It is a well-established fact that statistical properties of energy-level spectra are the most efficient tool to characterize nonintegrable quantum systems. The statistical behavior of different systems such as complex atoms, atomic nuclei, two-dimensional Hamiltonians, quantum billiards, and noninteracting many bosons has been studied. The study of statistical properties and spectral fluctuations in interacting many-boson systems has developed interest in this direction. We are especially interested in weakly interacting trapped bosons in the context of Bose-Einstein condensation (BEC) as the energy spectrum shows a transition from a collective nature to a single-particle nature with an increase in the number of levels. However this has received less attention as it is believed that the system may exhibit Poisson-like fluctuations due to the existence of an external harmonic trap. Here we compute numerically the energy levels of the zero-temperature many-boson systems which are weakly interacting through the van der Waals potential and are confined in the three-dimensional harmonic potential. We study the nearest-neighbor spacing distribution and the spectral rigidity by unfolding the spectrum. It is found that an increase in the number of energy levels for repulsive BEC induces a transition from a Wigner-like form displaying level repulsion to the Poisson distribution for P(s). It does not follow the Gaussian orthogonal ensemble prediction. For repulsive interaction, the lower levels are correlated and manifest level-repulsion. For intermediate levels P(s) shows mixed statistics, which clearly signifies the existence of two energy scales: external trap and interatomic interaction, whereas for very high levels the trapping potential dominates, generating a Poisson distribution. Comparison with mean-field results for lower levels are also presented. For attractive BEC near the critical point we observe the Shnirelman-like peak near s = 0, which signifies the presence of a large number of quasidegenerate states.
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Portable system of energy dispersive X-ray fluorescence was used to determine the elemental composition of 68 pottery fragments from Sambaqui do Bacanga, an archeological site in Sao Luis, Maranhao, Brazil. This site was occupied from 6600 BP until 900 BP. By determining the element chemical composition of those fragments, it was possible to verify the existence of engobe in 43 pottery fragments. Obtained from two-dimensional graphs and hierarchical cluster analysis performed in fragments of stratigraphies from surface and 113-cm level, and 10 to 20, 132 and 144-cm level, it was possible to group these fragments in five distinct groups, according to their stratigraphies. The results of data grouping (two-dimensional graphics) are in agreement with hierarchical cluster analysis by Ward method. Copyright (C) 2011 John Wiley & Sons, Ltd.