Chaotic component obscured by strong periodicity in voice production system

Abstract

The effect of glottal aerodynamics in producing the nonlinear characteristics of voice is investigated by comparing the outputs of the asymmetric composite model and the two-mass model. The twomass model assumes the glottal airflow to be laminar, nonviscous, and incompressible. In this model, when the asymmetric factor is decreased from 0.65 to 0.35, only 1:1 and 1:2 modes are detectable. However, with the same parameters, four vibratory modes (1:1, 1:2, 2:4, 2:6) are found in the asymmetric composite model using the Navier-Stokes equations to describe the complex aerodynamics in the glottis. Moreover, the amplitude of the waveform is modulated by a smallamplitude noiselike series. The nonlinear detection method reveals that this noiselike modulation is not random, but rather it is deterministic chaos. This result agrees with the phenomenon often seen in voice, in which the voice signal is strongly periodic but modulated by a small-amplitude chaotic component. The only difference between the two-mass model and the composite model is in their descriptions of glottal airflow. Therefore, the complex aerodynamic characteristics of glottal airflow could be important in generating the nonlinear dynamic behavior of voice production, including bifurcation and a small-amplitude chaotic component obscured by strong periodicity.

Comparative study of approximate entropy and sample entropy robustness to spikes

“…Similar complex patterns, or chaotic behaviour, have also been studied in human voice 11 and have been reported to be related to voice disorders or some pathologies in some situations. 12 Because traditional PAM methods are limited, complimentary objective measures that are able to characterize and distinguish between chaotic and quasi-periodic acoustic events are desirable.…”

The impact of glottal area discontinuities on block-type vocal fold models with asymmetric tissue properties

“…The current ASM suggests, however, that the simple process of prescribing a continuous aerodynamic surface can significantly affect the overall model dynamics. Figure 4 compares the displacement histories from simulations of SH95 and ASM, as well as data sampled from the asymmetric composite model of Tao and Jiang, 7 labeled TJ08. Following Steinecke and Herzel, the medial-lateral mass displacements are given by x 1,a , where the second subscript is again either l or r.…”

“…The ASM exhibits oscillatory behavior similar to that observed by Tao and Jiang. 7 Otherwise identical to SH95, their asymmetric composite model implements a discrete solution to the full Navier-Stokes equations to describe the fluid flow. The geometry of their vocal folds is described by two polynomials, one for the glottal entrance and one for the glottal exit, creating a smooth and continuous aerodynamic surface.…”

“…Note that the contact forces are not corrected 6 in the current study to enable direct comparison with previously published results. 2,7 Deviations of a min from either the a 1 or a 2 curves, when both are greater than zero, indicate that a min is at the junction between the inferior and superior masses, see, for example, t % 5 ms, t % 8 ms, and t % 16.5 ms in Fig. 1(b).…”

Design and Implementation of Network Public Opinion Monitoring System Based on Tibetan

“…Tibetan word segmentation technology, the method of determining Tibetan encoding conversion and the combination of case grammar and dictionary were also investigated and discussed in detail. The literature [6] focused on the automatic segmentation algorithm, Tibetan web page conversion algorithm, different Tibetan encoding to national standard A expansion algorithm and automatic word segmentation algorithm. A kind of information filtering model based on semantic analysis was designed in the literature [7] .…”