scholarly journals A Speech Preprocessing Method Based on Perceptually Optimized Envelope Processing to Increase Intelligibility in Reverberant Environments

2021 ◽  
Vol 11 (22) ◽  
pp. 10788
Author(s):  
Ali Fallah ◽  
Steven van de Par
Keyword(s):  
Cost Function ◽  
Speech Intelligibility ◽  
Time Slot ◽  
Time Varying ◽  
Public Places ◽  
Optimization Framework ◽  
Look Ahead ◽  
Variant Filtering ◽  
Reverberant Environments ◽  
Envelope Processing

Speech intelligibility in public places can be degraded by the environmental noise and reverberation. In this study, a new near-end listening enhancement (NELE) approach is proposed in which using a time varying filter jointly enhances the onsets and reduces the overlap masking. For optimization, some look-ahead in clean speech and prior knowledge of room impulse response (RIR) are required. In this method, by optimizing a defined cost function, the Spectro-Temporal Envelope of reverb speech is optimized to be as close as possible to that of clean speech. In this cost function, onsets of speech are optimized with increased weight. This approach is different from overlap-masking ratio (OMR) and speech enhancement (OE) approaches (Grosse, van de Par, 2017, J. Audio Eng. Soc., Vol. 65(1/2), pp. 31–41) that only consider previous frames in each time slot for determining the time variant filtering. The SRT measurements show that the new optimization framework enhances the speech intelligibility up to 2 dB more that OE.

Quasi-Sliding Mode Control for Impulsive Delayed Vehicle Longitudinal Following System with Bounded and Varying Parameters

2013 ◽  
Vol 300-301 ◽  
pp. 1436-1443
Author(s):  
Xiao Hui Xu ◽  
Wen Chao Fu ◽  
Ji Ye Zhang ◽  
Wang Xi
Keyword(s):  
Sliding Mode Control ◽  
Drag Coefficient ◽  
Sliding Mode ◽  
Impulsive Effect ◽  
Time Varying ◽  
Varying Parameters ◽  
Mode Control ◽  
Look Ahead ◽  
Automated Highway ◽  
Highway System

In the real automated highway system, various factors to vehicles which are moving make the velocity of vehicles change suddenly. In this paper, assuming that the mass of vehicles, the drag coefficient and the resistance of the ground were uncertain, the controller for a class of time-varying delayed look-ahead vehicle longitudinal following system with impulsive effect was designed by using the idea of quasi-sliding mode control. An example is given at last to test the controller proposed in this paper.

Energy Cost Optimization of HVAC Loads Under Time-Varying Electricity Price Signals

2016 ◽  
Author(s):  
Saeid Bashash
Keyword(s):  
Dynamic Programming ◽  
Cost Function ◽  
Energy Cost ◽  
Optimal Operation ◽  
Electricity Price ◽  
Programming Approach ◽  
Time Varying ◽  
Temperature Deviation ◽  
Price Signals ◽  
The Cost

This paper presents a dynamic programming approach to optimize energy cost of multiple interacting household appliances such as air conditioning systems and refrigerators with temperature flexibility, under time varying electricity price signals. We adopt a first order differential equation model with a binary (ON-OFF) switching control function for each load. An energy cost minimization problem is then formulated with a pair of constraints on the temperature lower and upper bounds, as well as an equality condition on the initial and final temperature states. We use dynamic programming to compute cost-optimal control inputs and temperature trajectories for a given electricity price profile and ambient temperature condition. To account for temperature deviation from its desired setpoint, a quadratic temperature deviation penalty is added to the cost function. Moreover, to minimize the control input chattering for equipment protection, the cost function is expanded to also minimize the number of on-off switching events. Results for the different weighting combinations of the optimization objectives provide useful insights on the optimal operation of individual and multiple interacting HVAC loads. In particular, we observe that the loads are desynchronized under the cost-optimal operation, in the presence of local (renewable) power generation. The presented optimization algorithm and observed results can lead to the development of novel model predictive and rule-based feedback control policies for optimal energy management in households.

scholarly journals Interactions Between Digital Noise Reduction and Reverberation: Acoustic and Behavioral Effects

2020 ◽  
Vol 31 (01) ◽  
pp. 017-029
Author(s):  
Paul Reinhart ◽  
Pavel Zahorik ◽  
Pamela Souza
Keyword(s):  
Noise Reduction ◽  
Hearing Impairment ◽  
Hearing Aids ◽  
Background Noise ◽  
Speech Intelligibility ◽  
Spectral Subtraction ◽  
Listening Effort ◽  
Speech In Noise ◽  
Reverberant Environments ◽  
Speech Naturalness

AbstractDigital noise reduction (DNR) processing is used in hearing aids to enhance perception in noise by classifying and suppressing the noise acoustics. However, the efficacy of DNR processing is not known under reverberant conditions where the speech-in-noise acoustics are further degraded by reverberation.The purpose of this study was to investigate acoustic and perceptual effects of DNR processing across a range of reverberant conditions for individuals with hearing impairment.This study used an experimental design to investigate the effects of varying reverberation on speech-in-noise processed with DNR.Twenty-six listeners with mild-to-moderate sensorineural hearing impairment participated in the study.Speech stimuli were combined with unmodulated broadband noise at several signal-to-noise ratios (SNRs). A range of reverberant conditions with realistic parameters were simulated, as well as an anechoic control condition without reverberation. Reverberant speech-in-noise signals were processed using a spectral subtraction DNR simulation. Signals were acoustically analyzed using a phase inversion technique to quantify improvement in SNR as a result of DNR processing. Sentence intelligibility and subjective ratings of listening effort, speech naturalness, and background noise comfort were examined with and without DNR processing across the conditions.Improvement in SNR was greatest in the anechoic control condition and decreased as the ratio of direct to reverberant energy decreased. There was no significant effect of DNR processing on speech intelligibility in the anechoic control condition, but there was a significant decrease in speech intelligibility with DNR processing in all of the reverberant conditions. Subjectively, listeners reported greater listening effort and lower speech naturalness with DNR processing in some of the reverberant conditions. Listeners reported higher background noise comfort with DNR processing only in the anechoic control condition.Results suggest that reverberation affects DNR processing using a spectral subtraction algorithm in such a way that decreases the ability of DNR to reduce noise without distorting the speech acoustics. Overall, DNR processing may be most beneficial in environments with little reverberation and that the use of DNR processing in highly reverberant environments may actually produce adverse perceptual effects. Further research is warranted using commercial hearing aids in realistic reverberant environments.

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