Escuela Superior de Enseñanzas Técnicas

Accurate predictions of environmental noise levels are necessary to implement noise reduction strategies in urban areas. In this paper, a stochastic model is introduced to describe and predict the L(den), L(day), L(evening), and L(night) levels. A Gaussian Ornstein-Uhlenbeck model is used to represent the dynamics of the noise levels, where the mean-reversion properties and seasonal volatility for each day of the week are studied separately.

This paper summarises 5 years of continuous noise measurements carried out at one of the most important squares in Valencia (Spain). The chosen square is a clear hotspot for traffic noise in a large city. The aim of this study is to determine the appropriate measuring time in order to obtain a 24-h noise level suitable to represent the annual equivalent level. Our findings allow us to reach a number of conclusions in terms of the most suitable urban traffic noise measurement techniques. A random day strategy for sampling is found to give a more accurate representation than a consecutive days strategy. If the sampling strategy involves measurements on randomly-chosen days, then at least 6 days should be used.

A proper estimation of the chiral low-energy constants of Chiral Perturbation Theory is a very important task. To this end resonance chiral Lagrangians have been used fruitfully. We have studied the determination of chiral couplings at next-to-leading (NLO) order in the 1=NC expansion, keeping full control of the renormalization scale dependence. We find that, by imposing shortdistance constraints coming from QCD, resonance saturation at NLO in 1=NC is satisfied. In other words, the chiral couplings can be written in terms of the resonance masses and couplings and do not depend explicitly on the coefficients of the chiral operators in the Goldstone boson sector of Resonance Chiral Theory.