Comparison Between Kriging Variance and Interpolation Variance as Uncertainty Measurements in the Capanema Iron Mine, State of Minas Gerais—Brazil     

Marcelo Monteiro da Rocha  Jorge Kazuo Yamamoto 《Natural Resources Research》2000,9(3):223-235

The Capanema Mine, an iron ore deposit, is located in the central portion of the Quadrilátero Ferrífero, State of Minas Gerais, southeastern Brazil. Mine development data from approximately 7000 drillholes were used for a comparative study between kriging variance and interpolation variance as uncertainty measurements associated with ordinary kriging estimates. As known, the traditional kriging variance does not depend on local data and, therefore, does not measure the actual dispersion of data. On the other hand, the interpolation variance measures adequately the local dispersion of data used for an ordinary kriging estimate. This paper presents an application of the concept of interpolation variance for measuring uncertainties associated with ordinary kriging estimates of Fe and silica grades. These data were selected for their distinct statistical characteristics with Fe presenting a negatively skewed distribution and, consequently, a low dispersion, and silica a positively skewed distribution and, therefore, a high variability. Comparative studies between the two uncertainty measurements associated with ordinary kriging estimates of Fe and silica proved the superiority of the interpolation variance as a reliable and precise alternative to the kriging variance.  相似文献   

危险目标再入跟踪预报研究     

吴连大  王昌彬 《紫金山天文台台刊》2000,19(2):100-105

本文讨论了危险目标再入的有关问题,通过２２８７０和２５１００两个卫星陨落期预报的实践,我们形成了一种计算卫星落点的方法,方法的基本要点是：１算准卫星的面质比;２在１８０公里以下,考虑阻尼系数随高度（大气密度）的变化;３在计算落点时,使用两组根数,调整面质比使两组根数计算的落点基本相同,并验证面质比调整的合理性;４对于ＭＳＩＳ－１９９０模式,我们发现调整后的面质比要比理论的面质比大１．０９倍,也许这  相似文献   

Centrifugal Forces and Optical Geometry in Neutron Stars     

P.C. Freire  A.A. da Costa 《Astrophysics and Space Science》2000,272(1-3):275-282

In this paper centrifugal forces and the geometry of light ray trajectories in neutron stars are discussed. The general behavior of centrifugal forces and angular momentum transfer is closely linked to the geometry of photon trajectories, such a behavior is here graphically depicted for realistic neutron stars, shown to be quite different from the non-relativistic case and to depend on the particular form of the equation of state. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Near-infrared sky background fluctuations at mid- and low latitudes     

G. Moreels  J. Clairemidi  M. Faivre  D. Pautet  F. Rubio da Costa  P. Rousselot  J.W. Meriwether  G.A. Lehmacher  E. Vidal  J.L. Chau  G. Monnet 《Experimental Astronomy》2008,22(1-2):87-107

The emission of the upper atmosphere introduces an additional variable component into observations of astronomical objects in the NIR 700–3,000 nm range. The subtraction of this component is not easy because it varies during the night by as much as 100% and it is not homogeneous over the sky. A program aimed at measuring and understanding the main characteristics of the atmospheric NIR emission was undertaken. A 512?×?512 CCD camera equipped with a RG780/2 mm filter is used to obtain images of the sky in a 36°?×?36° field of view. The intensities of a given star and of the nearby region devoid of star in a 439 arcmin² area are monitored during periods of time of several hours. The sky intensity measured in the 754–900 nm bandpass, reduced to zenith and zero airmass is comprised between mag20 and mag18.5 per arcsecond². A diminution by a factor of two during the night is frequently observed. Intensity fluctuations having an amplitude of 15% and periods of 5–40 min are present in the images with a structure of regularly spaced stripes. The fluctuations of the NIR sky background intensity are due to (1) the chemical evolution of the upper atmosphere composition during the night and (2) dynamical processes such as tides with periods of 3–6 h or gravity waves with periods of several tens of minutes. We suggest that a monitoring of the sky background intensity could be set up when quantitative observations of astronomical objects require exposure times longer than ~10 min. The publication is illustrated with several video films accessible on the web site http://www.obs-besancon.fr/nirsky/. Enter username: nirsky and password: skynir.  相似文献   

Preface     

Sebastian Wolf  Paulo J.V. Garcia   《New Astronomy Reviews》2008,52(2-5):19

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Historical changes in the functional connectivity of rivers based on spatial network analysis and the past occurrences of diadromous species in Portugal     

Pedro Segurado  Paulo Branco  Ana P. Avelar  Maria T. Ferreira 《Aquatic Sciences - Research Across Boundaries》2015,77(3):427-440

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Comparison of seismic analysis methods applied to a historical church struck by 2009 L’Aquila earthquake     

Yohei Endo  Luca Pelà  Pere Roca  Francesca da Porto  Claudio Modena 《Bulletin of Earthquake Engineering》2015,13(12):3749-3778

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Equatorial Atlantic Ocean dynamics in a coupled ocean–atmosphere model simulation     

Emanuel Giarolla  Leo San Pedro Siqueira  Marcus Jorge Bottino  Marta Malagutti  Vinicius Buscioli Capistrano  Paulo Nobre 《Ocean Dynamics》2015,65(6):831-843

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Shaking table testing of an existing masonry building: assessment and improvement of the seismic performance          下载免费PDF全文

Nuno Mendes  Paulo B. Lourenço  Alfredo Campos‐Costa 《地震工程与结构动力学》2014,43(2):247-266

This paper aims to assess and improve the seismic performance of an existing masonry building with flexible floors, representative of a Portuguese building typology—‘gaioleiro’ buildings. The study involved seismic tests and dynamic identification tests of two models (nonstrengthened and strengthened) in the shaking table. Each model was subjected to several seismic tests with increasing amplitude. Before the first test and after each seismic test, the dynamic identification of the model was carried out, aiming at obtaining their seismic vulnerability curves based on a damage indicator obtained from the decrease of the frequencies of the modes. In the strengthened model, steel elements were used to improve the connection between walls and floors, together with ties in the upper stories. The results show that adopted strengthening technique is effective for reducing the seismic vulnerability of ‘gaioleiro’ buildings, namely for improving the out‐of‐plane behavior of the facades. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Statistical analysis of a combination of objective and subjective environmental noise data using factor analysis and multinomial logistic regression   总被引：1，自引：1，他引：0  

Margret Sibylle Engel  Emerson Hochsteiner de Vasconcelos Segundo  Paulo Henrique Trombetta Zannin 《Stochastic Environmental Research and Risk Assessment (SERRA)》2014,28(2):393-399

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