A Deep Learning Loss Function based on Auditory Power Compression for Speech Enhancement

Deep learning technology has been widely applied to speech enhancement. While testing the effectiveness of various network structures, researchers are also exploring the improvement of the loss function used in network training. Although the existing methods have considered the auditory characteristics of speech or the reasonable expression of signal-to-noise ratio, the correlation with the auditory evaluation score and the applicability of the calculation for gradient optimization still need to be improved. In this paper, a signal-to-noise ratio loss function based on auditory power compression is proposed. The experimental results show that the overall correlation between the proposed function and the indexes of objective speech intelligibility, which is better than other loss functions. For the same speech enhancement model, the training effect of this method is also better than other comparison methods.Comment: 7 pages, 4 figure

The Nesterov-Spokoiny Acceleration Achieves Strict o(1/k2)o(1/k^2) Convergence

A lower bound result of Nesterov states that for a smooth convex objective $f \in \mathscr{F}_{L}^{\infty,1} (\mathbb{R}^n)$, an algorithm that satisfies $\mathbf{x}_{k+1} \in \mathbf{x}_0 + \mathrm{Lin} \{ \nabla f (\mathbf{x}_0), \cdots , \nabla f (\mathbf{x}_k) \}$ $(k\ge 0)$ cannot converge faster than $\Omega ( 1/k^2 )$ when $k$ is small. In this paper, we show that when $k$ is large, this worst-case lower bound is a bit overly pessimistic. We introduce a variant of an accelerated gradient algorithm of Nesterov and Spokoiny. We call this algorithm the Nesterov-Spokoiny Acceleration (NSA). The NSA algorithm simultaneously satisfies the following properties. 1. The sequence $\{ \mathbf{x}_k \}_{k \in \mathbb{N}}$ governed by NSA obeys $\mathbf{x}_{k+1} \in \mathbf{x}_0 + \mathrm{Lin} \{ \nabla f (\mathbf{x}_0), \cdots , \nabla f (\mathbf{x}_k) \}$ $(k\ge 0)$, and 2. For a smooth convex objective $f \in \mathscr{F}_{L}^{\infty,1} (\mathbb{R}^n)$, the sequence $\{ \mathbf{x}_k \}_{k \in \mathbb{N}}$ governed by NSA satisfies $\limsup\limits_{k \to \infty } k^2 ( f (\mathbf{x}_k ) - f^* ) = 0$, where $f^* > -\infty$ is the minimum of $f$. To our knowledge, NSA is the first algorithm that simultaneously satisfies items 1 and 2

Analysis on the aerodynamic performance of vertical axis wind turbine subjected to the change of wind velocity

AbstractReynolds averaged Navier-Stokes equations and Realizable kɛ− model were used in this paper, and the two dimensional unsteady flow field of the vertical axis wind turbine was simulated numerically at different wind velocity. The calculation results showed that the velocity in the region of wind turbine's rotation was much larger than the air flow of the upstream. The length of the wind turbine's downstream wake dispersion region was increased with the increase of the wind velocity. There is a much larger value of the eddy in the rear region of the wind turbine's rotational blades. And eddy existed in the downstream region of the wind turbine, and the larger velocity of cross flow, the larger value of the downstream flow's eddy. When the rotational speed was constant, with the increase in wind velocity, the variation of the wind turbine's total torque coefficient tended to smooth. The calculation results pointed out the direction for the follow-up study

Experimental determination on the critical angle of seismic incidence of curved bridge

The shaking table model test mainly focuses on the study of seismic response law, aseismic performance and seismic damping and isolation effect of bridges with a single or multi-platform shaking table. Basically, the plane principal axis direction is adopted for the seismic input of structural models. Little research effort considering multi-angle seismic input has been reported in the structural model test. In this paper we designed and conducted a small-scale shaking table model test to study the seismic response law of the curved girder bridges with seismic input at different angles, and provided experimental verification for the theoretical method of the most unfavorable angle of seismic input. The experimental results show that the variation trend of component response to variation of the seismic input direction is consistent with that of the numerical analysis, which indicates that the designed device is effective

Analysis on the influence of rotational speed to aerodynamic performance of vertical axis wind turbine

AbstractA two dimensional vertical axis wind turbine's model was established in this paper, and two dimensional unsteady incompressible N-S equations and Realizable kɛ− turbulence model were solved with software FLUENT. SIMPLC algorithm was applied, combined with the sliding grid technology; the influence of rotational speed to the flow structure of vertical axis wind turbine was discussed. The results showed that, the rotation of wind turbine had significant influence on wake, and higher the rotational speed, the greater reduction of the wake velocity. The wake velocity restored gradually away from the rotational part. There was much larger turbulent kinetic energy near the tail of the wind turbine's blade. The value of turbulent kinetic energy reduced gradually away from the rotational part, and the flow restored the stratospheric state gradually. With the increase of wind turbine's rotational speed, the value of turbulent kinetic energy in calculation domain increased too. The results showed that the flow structure of vertical axis wind turbine's rotational process could be revealed effectively by numerical simulation, provided theoretical reference for the engineering design of the vertical axis wind turbine

Electromagnetically induced transparency of interacting Rydberg atoms with two-body dephasing

We study electromagnetically induced transparency in a three-level ladder type configuration in ultracold atomic gases, where the upper level is an electronically highly excited Rydberg state. An effective distance dependent two-body dephasing can be induced in a regime where dipole-dipoles interaction couple nearly degenerate Rydberg pair states. We show that strong two-body dephasing can enhance the excitation blockade of neighboring Rydberg atoms. Due to the dissipative blockade, transmission of the probe light is reduced drastically by the two-body dephasing in the transparent window. The reduction of transmission is accompanied by a strong photon-photon anti-bunching. Around the Autler-Townes doublets, the photon bunching is amplified by the two-body dephasing, while transmission is largely unaffected. Besides relevant to the ongoing Rydberg atom studies, our study moreover provides a setting to explore and understand two-body dephasing dynamics in many-body systems

THREE DIMENSIONAL KINEMATIC ANALYSIS IN WOMEN’S SHOT PUTT: INFLUENCE OF HEAD MOVEMENT ON TECHNIQUE

The influence of head motion of shot put during competition was studied in this study. Six female elite shot putter was recruited as subjects in this study. Shots performed by six female elite shot putter were filmed. Three-dimensional analysis was employed to determine the angle of head, trunk, shoulder rotation and height of shot at different throwing phase. Results found that the raising of head position in every phase influenced the movements limb and trunk. Therefore, it is necessary for coach and athletes to pay more attention on the head movement in shot put

Highly efficient vortex four-wave mixing in asymmetric semiconductor quantum wells

© 2020 Optical Society of America under the terms of the OSA Open Access Publishing Agreement Orbital angular momentum (OAM) is an important property of vortex light, which provides a valuable tool to manipulate the light-matter interaction in the study of classical and quantum optics. Here we propose a scheme to generate vortex light fields via four-wave mixing (FWM) in asymmetric semiconductor quantum wells. By tailoring the probe-field and control-field detunings, we can effectively manipulate the helical phase and intensity of the FWM field. Particularly, when probe field and control field have identical detuning, we find that both the absorption and phase twist of the generated FWM field are significantly suppressed. Consequently, the highly efficient vortex FWM is realized, where the maximum conversion efficiency reaches around 50%. Our study provides a tool to transfer vortex wavefronts from input to output fields in an efficient way, which may find potential applications in solid-state quantum optics and quantum information processing