Search results for "Curve"

Computing Difficulties for Deriving Poverty Indices from Some Functional Forms of Lorenz Curves

2014

We examine three families of classical one-parameter functional forms for estimating a Lorenz curve: the power form (Pareto, elementary form), the exponential form (Gupta, elementary form) and fractional form (Rohde). For the first time, we systematically study these functions not for their ability to be estimated but on the point of view of the possibility of deriving poverty indices, which implies first determining the headcount ratio (i.e., the percentage of poor). We show that computing difficulties have been largely underestimated. Two forms, the most simple ones, pose no problem: the elementary power and exponential forms. However, the Pareto functional form poses problem with a restr…

A new approach for estimating a nonlinear growth component in multilevel modeling

2011

This study presents a new approach to estimation of a nonlinear growth curve component with fixed and random effects in multilevel modeling. This approach can be used to estimate change in longitudinal data, such as day-of-the-week fluctuation. The motivation of the new approach is to avoid spurious estimates in a random coefficient regression model due to the synchronized periodical effect (e.g., day-of-the-week fluctuation) appearing both in independent and dependent variables. First, the new approach is introduced. Second, a Monte Carlo simulation study is carried out to examine the functioning of the proposed new approach in the case of small sample sizes. Third, the use of the approac…

Curvelet-based method for orientation estimation of particles

2013

A method based on the curvelet transform is introduced for estimating from two-dimensional images the orientation distribution of small anisotropic particles. Orientation of fibers in paper is considered as a particular application of the method. Theoretical aspects of the suitability of this method are discussed and its efficiency is demonstrated with simulated and real images of fibrous systems. Comparison is made with two traditionally used methods of orientation analysis, and the new curvelet-based method is shown to perform clearly better than these traditional methods.

Curvelet-based method for orientation estimation of particles from optical images

2014

A method based on the curvelet transform is introduced to estimate the orientation distribution from two-dimensional images of small anisotropic particles. Orientation of fibers in paper is considered as a particular application of the method. Theoretical aspects of the suitability of this method are discussed and its efficiency is demonstrated with simulated and real images of fibrous systems. Comparison is made with two traditionally used methods of orientation analysis, and the new curvelet-based method is shown to perform better than these tradi- tional methods. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of th…

The Equiangular Compass

2012

THE RELATIONSHIP BETWEEN UNEMPLOYMENT AND INFLATION IN POLAND AND THE PHILLIPS CURVE

2018

W części teoretycznej artykułu przedstawiono ewolucję poglądów na temat krzywej Phillipsa. Przybliżono model A. W. Phillipsa z 1958 r., a także liczne rozwinięcia tego modelu autorstwa takich ekonomistów, jak: P. Samuelson, R. Solow, M. Friedman, E. Phelps, R. Lucas, E. Kydland i E. Prescott. Wprowadzenie teoretyczne dopełnia przegląd dotychczasowego dorobku literatury światowej z zakresu weryfikacji empirycznej krzywej Phillipsa. Celem części empirycznej niniejszej pracy jest zbadanie istnienia krzywej Phillipsa w gospodarce polskiej w latach 1990-2010. Sprawdzono kierunek i siłę związku stóp inflacji i bezrobocia na podstawie danych miesięcznych, kwartalnych, półrocznych i rocznych. W bad…

Visual Contrast Modulates Operant Learning Responses in Larval Zebrafish.

2018

The larval zebrafish is a promising vertebrate model organism to study neural mechanisms underlying learning and memory due to its small brain and rich behavioral repertoire. Here, we report on a high-throughput operant conditioning system for zebrafish larvae, which can simultaneously train 12 fish to associate a visual conditioned pattern with electroshocks. We find that the learning responses can be enhanced by the visual contrast, not the spatial features of the conditioned patterns, highlighted by several behavioral metrics. By further characterizing the learning curves as well as memory extinction, we demonstrate that the percentage of learners and the memory length increase as the co…

Dating archaeological copper/bronze artifacts by using the voltammetry of microparticles.

2014

A method for dating copper/bronze archaeological objects aged in atmospheric environments is proposed based on the specific signals for cuprite and tenorite corrosion products measured through the voltammtry of microparticles method. The tenorite/cuprite ratio increased with the corrosion time and fitted to a potential law that yielded a calibration curve usable for dating purposes.

Public-private sector pay gaps over the business cycle :

2010

The wage curve and local monopsony power

2019

AbstractUsing longitudinal micro-data from Finland, a country with a geographically dispersed population and relatively long distances between local labor markets, this paper examines the responsiveness of the pay level to local unemployment conditions. In particular, this study tests the hypothesis that the pay level is more responsive to the unemployment level in less agglomerated and more remote regions as might be expected if employers have a higher degree of monopsony power in such regions. The results consistently suggest that the pay level is lower in localities with a higher unemployment level and, hence, provide strong support for the so-called wage curve hypothesis, which predicts…