Speech enhancement for vehicle hands-free mobile telephony

International audienc

Assessment of the contribution of time reversal on a UWB localization system for railway applications

UWB radio has the potential to offer good perfor- mance in terms of localization precision. Time Reversal chan- nel pre-filtering facilitates signal detection and also helps to increase the received energy in a targeted area. This paper assesses the quantitative and qualitative contributions of the Time Reversal (TR) technique associated with an Ultra Wide- band (UWB) localization system applied to a railway odometry problem. The analytical and simulation results for Power Delay Profile, equivalent channel model and focusing gain of the TR- UWB are given. The contribution of the TR technique associ- ated with UWB radio to enhance the localization resolution is analysed. To perform these studies, and to be representative of the proposed railway application, a deterministic channel model is used. The analytical simulation and experimental results show that time reversal has very promising characteristics regarding its association with the UWB in terms of localization error. These results also indicate that the TR-UWB technique delivers improved performance over UWB only localization approach, that could benefit the development of the proposed railway application

Parameter estimation for VLE calculation by global minimization: the genetic algorithm

Vapor-liquid equilibrium calculations require global minimization of deviations in pressure and gas phase compositions. In this work, two versions of a stochastic global optimization technique, the genetic algorithm, the freeware MyGA program, and the modified mMyGA program, are evaluated and compared for vapor-liquid equilibrium problems. Reliable experimental data from the literature on vapor liquid equilibrium for water + formic acid, tert-butanol + 1-butanol and water + 1,2-ethanediol systems were correlated using the Wilson equation for activity coefficients, considering acid association in both liquid and vapor phases. The results show that the modified mMyGA is generally more accurate and reliable than the original MyGA. Next, the mMyGA program is applied to the CO2 + ethanol and CO2 + 1-n-butyl-3-methylimidazolium hexafluorophosphate systems, and the results show a good fit for the data