Search results for "Estimates"

Global endemics-area relationships of vascular plants

2019

Endemics–Area Relationships (EARs)are fundamental in theoretical and applied biogeography for understanding distribution patterns and promoting biodiversity conservation. However, calculating EARs for vascular plant species from existing data is problematic because of biased knowledge of endemic species distributions and differences between taxonomies. We aimed to overcome these challenges by developing a new standardized global dataset based on expert knowledge to produce a set of global EARs. We developed a nested circle design, with grain sizes of 10 4 , 10 5 , 10 6 , 10 7 , and 10 8 km 2 , respectively, and a global distribution of plots based on a stratified random scheme. The number …

Estimating the size of the loan sharking market in Italy

2014

In the current economic crisis, the risk is so high that entrepreneurs, commercial activities and even families may turn to the illegal market to obtain liquidity. This article proposes an estimate of the size of the usury credit market in Italy. The estimate is based on the assumption, provided by Guiso1, that before coming to a moneylender the borrower seeks to obtain credit through official channels. The results of our estimates confirm the seriousness of the problem, but provide much lower data than those reported periodically by the media. It is estimated that 372,000 economic activities may have been potentially involved in the usury market in 2012. The volume of loans disbursed in th…

A posteriori estimates for the stationary Stokes problem in exterior domains

2020

This paper is concerned with the analysis of the inf-sup condition arising in the stationary Stokes problem in exterior domains and applications to the derivation of computable bounds for the distance between the exact solution of the exterior Stokes problem and a certain approximation (which may be of a rather general form). In the first part, guaranteed bounds are deduced for the constant in the stability lemma associated with the exterior domain. These bounds depend only on known constants and the stability constant related to bounded domains that arise after suitable truncations of the unbounded domains. The lemma in question implies computable estimates of the distance to the set of di…

Thin obstacle problem : Estimates of the distance to the exact solution

2018

We consider elliptic variational inequalities generated by obstacle type problems with thin obstacles. For this class of problems, we deduce estimates of the distance (measured in terms of the natural energy norm) between the exact solution and any function that satisfies the boundary condition and is admissible with respect to the obstacle condition (i.e., they are valid for any approximation regardless of the method by which it was found). Computation of the estimates does not require knowledge of the exact solution and uses only the problem data and an approximation. The estimates provide guaranteed upper bounds of the error (error majorants) and vanish if and only if the approximation c…

On a global superconvergence of the gradient of linear triangular elements

1987

Abstract We study a simple superconvergent scheme which recovers the gradient when solving a second-order elliptic problem in the plane by the usual linear elements. The recovered gradient globally approximates the true gradient even by one order of accuracy higher in the L 2 -norm than the piecewise constant gradient of the Ritz—Galerkin solution. A superconvergent approximation to the boundary flux is presented as well.

Hybrid kernel estimates of space-time earthquake occurrence rates using the Etas model

2010

The following steps are suggested for smoothing the occurrence patterns in a clustered space–time process, in particular the data from an earthquake catalogue. First, the original data is fitted by a temporal version of the ETAS model, and the occurrence times are transformed by using the cumulative form of the fitted ETAS model. Then the transformed data (transformed times and original locations) is smoothed by a space–time kernel with bandwidth obtained by optimizing a naive likelihood cross-validation. Finally, the estimated intensity for the original data is obtained by back-transforming the estimated intensity for the transformed data. This technique is used to estimate the intensity f…

Fully reliable a posteriori error control for evolutionary problems

2015

Table Compression

2016

Data Compression Techniques for massive tables are described. Related methodological results are also presented.

A Posteriori Error Bounds for Approximations of the Oseen Problem and Applications to the Uzawa Iteration Algorithm

2014

Abstract. We derive computable bounds of deviations from the exact solution of the stationary Oseen problem. They are applied to approximations generated by the Uzawa iteration method. Also, we derive an advanced form of the estimate, which takes into account approximation errors arising due to discretization of the boundary value problem, generated by the main step of the Uzawa method. Numerical tests confirm our theoretical results and show practical applicability of the estimates.

“The Limits” of Economic Growth in Romania

2014

Abstract A sustainable economic growth of GDP of 3-4% annually in Romania for the reduction of gaps in development was considered impossible by most institutions of various skill and opinion leaders, as well as of international financial bodies. The reasons cited were delayed public reforms, low growth potential as a result of the crisis, the overview status of the states in the Eurozone dependent on inside community trade and also the prospects for a lasting economic stagnation, the balance sheet effect, as a result of over indebtedness of firms and individuals that substantially reduced inclination towards investment and consumption. Contradicting these forecasts, in 2013, Romania's econo…