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Robust microphone array using subband adaptive beamformer and spectral subtraction

This paper presents a new robust microphone array to enhance speech signal under the influence of noise and jammer(s). The proposed structure comprises of a soft constrained subband beamformer, a blocking system and a non-coherent processing technique. The soft constrained beamformer enhances the desired speech signal in a specified region by suppressing all side-lobes. This enhanced signal is the

Investigation of photochemical effects in flame diagnostics with picosecond photofragmentation laser-induced fluorescence

Photofragmentation laser-induced fluorescence (PFLIF) is for the first time performed based on picosecond laser pulses for detection of hydroperoxyl radicals (HO2) in a stoichiometric laminar methane/air flame. Photofragmentation is performed with a pump laser pulse of 80 ps duration and a wavelength of 266 nm, whereupon the produced OH photofragments are detected by a second picosecond probe lase

Spatial Interference Cancellation using Blind Signal Separation and Sector Antennas

In order to increase the capacity of a mobile radio network, it is desirable to exploit the spatial domain in an efficient way. A common technique is to use a sector antennas. Sectors can be formed by using antenna arrays which add spatial domain selectivity in order to improve the Signal-to-Noise and Interference Ratio (SNIR). In this paper an interference cancellation scheme is presented that co

Design of Oversampled Uniform DFT Filter Banks with Delay Specifications using Quadratic Optimization

Subband adaptive filters have been proposed to avoid the drawbacks of slow convergence and high computational complexity associated with time domain adaptive filters. Subband processing introduces transmission delays caused by the filter bank and signal degradations due to aliasing effects. One efficient way to reduce the aliasing effects is to allow a higher sample rate than critically needed in

A Spatially Constrained Subband Beamforming Algorithm for Speech Enhancement

This paper discusses speech enhancement in an enclosed environment such as communication in a motorcycle helmet. A new constrained subband adaptive beamformer is proposed, which uses the concept of an earlier proposed calibrated beamformer mainly developed for a hands-free in-car environment. The highly non-stationary nature of the disturbing sound field encountered in an motorcycle helmet and the

Computer and smartphone continuance intention: A motivational model

This paper develops and tests a motivational model to explain the overall continuance intention to use computers and smartphones. Based on survey data from 192 undergraduate students, structural equation modeling analysis is used to report: (1) the independent effect of intrinsic motivation on the continuance intention to use computers and smartphones; (2) the independent effect of extrinsic motiv

Effects of facial expression on working memory

In long-term memory (LTM) emotional content may both enhance and impair memory, however, disagreement remains whether emotional content exerts different effects on the ability to maintain and manipulate information over short intervals. Using a working-memory (WM) recognition task requiring the monitoring of faces displaying facial expressions of emotion, participants judged each face as identical

Strategies for Quantitative Planar Laser-Induced Fluorescence of NH Radicals in Flames

Laser-induced fluorescence imaging of the NH radical using excitation in the (0-0) and (1-0) vibrational bands of the A3Π-X3Σ– electronic transition is characterized in premixed NH3-air flames. Filtered detection for excitation of the (1-0) band is found to be beneficial for measurement conditions with a challenging background and/or interferences. Concentration evaluation for excitation in the (0

Stochastic analysis of nucleation rates

We show that approximating the Becker-Döring equations with a Langevin equation results in multiplicative noise, which in turn leads to a family of possible Fokker-Planck equations according to the Ito-Stratonovich dilemma. Using a simple and general model for the attachment and detachment rates, we find that the Ito choice approximates the nucleation rate best and also coincides with the Fokker-P

Amplifier Design Using Vertical InAs Nanowire MOSFETs

In this paper, an amplifier design using ballistic vertical InAs nanowire (NW) transistors is investigated, focusing on a basic common-source amplifier. The maximum power gain at 90 GHz is evaluated for different NW transistor architectures together with the power dissipation. The linearity of the amplifier is evaluated by estimating the IIP3 and 1-dB compression points. Furthermore, the impact of