Search results for "difference [rapidity]"

Broadband printed dipole with integrated via-hole balun for WiMAX applications

2010

A broadband balanced printed dipole antenna for WiMAX applications (2.5/3.6 GHz) is presented. An integrated via-hole balun is used to feed the antenna and a Yagi-like scheme is proposed to improve the gain. The design has been optimized by means of parametric FDTD simulations. The antenna was fabricated and measured, giving a bandwidth higher than 50% and a gain higher than 4 dBi. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 53:52–55, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.25671

Relative differential forms and complex polynomials

2000

FDTD characterization of evanescent modes-multimode analysis of waveguide discontinuities

2000

In this paper, a finite-difference time-domain numerical dispersion relation for evanescent waves is derived, and its impact on the modeling accuracy is studied. The numerical evanescent constant is found to differ from the analytical one. As a result, a correction must be used to compute discontinuity parameters. This influences the reference plane chosen for the analysis of propagating modes. Moreover, on calculating multimode transmission and reflection coefficients, the dispersion for evanescent higher order modes is determinant. The dispersive relation is derived, discussed, and used to correct the evanescent constants for the multimode analysis of a waveguide discontinuity.

Tuition fees and student effort at university

2018

Abstract This paper presents theoretical and empirical evidence that an increase in tuition fees may boost university students’ academic effort. We examine the tuition fee rise introduced in 2012 by Spanish universities, where students register and pay for their chosen modules and fees increase each time students retake a module until they pass it. Data refer to students of economics, business and medicine at the University of Valencia during 2010–2014. The fact that some students pay fees in full while others are exempt from payment provides an identifying source of variation that we exploit using a flexible difference-in-differences methodology.

The economic impact of audit failures

2022

This paper examines the economic consequences associated with an audit failure in the field of statutory auditing services, by analyzing changes in the audit firm’s market share around the time of the investigation process undertaken by the Spanish Public Oversight Board. We explore the variations in audit market share by applying the difference in differences method to a treatment group of 70 sanctioned audit firms and a matched control group of 70 non-sanctioned audit firms. The period of analysis covers the years from 1999 to 2015. Our results show that the sanctioned audit firms suffered a significant decrease in their relative number of clients. Moreover, this measure of market share d…

Hydraulic kinetics of the graft union in different Olea europaea L. scion/rootstock combinations

2007

The hydraulic resistance of young olive trees grafted on rootstocks with contrasting size-controlling potential was measured 30, 90, 360 and 480 days after grafting. Olive (Olea europaea L.) clones inducing plant vigorous growth (Leccino ‘Minerva’, LM) or dwarfing (Leccino ‘Dwarf’, LD) were studied in different scion/rootstock combinations (LD/LD, LD/LM, LM/LD, LM/LM). Plants growing on LD root systems developed lower leaf surface areas (about 50% less) than plants grafted on LM rootstocks. Graft union represented the largest fraction (up to 85%) of whole-plant hydraulic resistance 30 days after grafting, and still represented an important fraction of it 2 months later (40–55%). Four-hundre…

CARATTERIZZAZIONE ELETTROMAGNETICA DEL COMPORTAMENTO DINAMICO DI ELETTRODI INTERRATI IN PRESENZA DI IONIZZAZIONE DEL TERRENO

2009

Time-dependent weak rate of convergence for functions of generalized bounded variation

2016

Let $W$ denote the Brownian motion. For any exponentially bounded Borel function $g$ the function $u$ defined by $u(t,x)= \mathbb{E}[g(x{+}\sigma W_{T-t})]$ is the stochastic solution of the backward heat equation with terminal condition $g$. Let $u^n(t,x)$ denote the corresponding approximation generated by a simple symmetric random walk with time steps $2T/n$ and space steps $\pm \sigma \sqrt{T/n}$ where $\sigma > 0$. For quite irregular terminal conditions $g$ (bounded variation on compact intervals, locally H\"older continuous) the rate of convergence of $u^n(t,x)$ to $u(t,x)$ is considered, and also the behavior of the error $u^n(t,x)-u(t,x)$ as $t$ tends to $T$

Design & Optimization of Large Cylindrical Radomes with Subcell and Non-Orthogonal FDTD Meshes Combined with Genetic Algorithms

2021

The word radome is a contraction of radar and dome. The function of radomes is to protect antennas from atmospheric agents. Radomes are closed structures that protect the antennas from environmental factors such as wind, rain, ice, sand, and ultraviolet rays, among others. The radomes are passive structures that introduce return losses, and whose proper design would relax the requirement of complex front-end elements such as amplifiers. The radome consists mostly in a thin dielectric curved shape cover and sometimes needs to be tuned using metal inserts to cancel the capacitive performance of the dielectric. Radomes are in the near field region of the antennas and a full wave analysis of th…

The Road to Higher Prices: Will Improved Road Standards Lead to Higher Housing Prices?

2020

AbstractWe study the impact of improved road standards on housing prices in a region of Southern Norway, where towns are located along the coast, like pearls on a string, with sparsely populated areas between the towns. In this region towns have since long been linked together by a road, but in 2009 a new highway, roughly parallel to the old road, was opened. The new highway runs Eastwards from the main town in the region and reduced one-way commutes to the main town by 10–15 min. We examine how this change in transportation infrastructure has affected housing prices, using difference-in-difference regressions to identify the impact of the new highway. Three smaller towns located East of th…