Multi-Dimensional Variation in Adult Speech as a Function of Age

We present a multidimensional acoustic report describing variation in speech productions on data collected from 500 francophone adult speakers (20 to 93 y.o.a.) as a function of age. In this cross-sectional study, chronological age is considered as a continuous variable while oral productions, in reading and speech-like tasks, are characterized via 22 descriptors related to voice quality, pitch, vowel articulation and vocalic system organization, time-related measures and temporal organization, as well as maximal performances in speech-like tasks. In a first analysis, we detail how each descriptor varies according to the age of the speaker, for male and female speakers separately. In a second analysis, we explore how chronological age is, in turn, predicted by the combination of all descriptors. Overall, results confirm that with increasing age, speakers show more voice instability, sex-dependent pitch changes, slower speech and articulation rates, slower repetition rates and less complexity effects in maximal performance tasks. A notable finding of this study is that some of these changes are continuous throughout adulthood while other appear either at old age or in early adulthood. Chronological age appears only moderately indexed in speech, mainly through speech rate parameters. We discuss these results in relation with the notion of attrition and with other possible factors at play, in an attempt to better capture the multidimensional nature of the notion of “age”.

Multi-point Sources Continuous Release Inversion Based on Improved Four-Dimensional Variation Method

the continuous release of multi-point sources is one of the most common cases in the field of air pollution. In order to solve the problem of multi-point sources continuous release inversion, a source intensity and location estimation method based on improved Four-Dimensional Variation is proposed. Firstly, by constructing the diffusion equation of multi-point sources continuous release and the monitoring concentration matrix, the source term inversion model of multi-point sources continuous release is formed. Secondly, the joint transformation method and Taylor series upwind difference method are used to solve the convection-diffusion equation of multi-point sources continuous release, and the numerical solution format of the forward problem is formed through simulation analysis. Furthermore, based on the numerical solution scheme of the forward problem, a four-dimensional variation inversion algorithm for multi-point sources continuous release is constructed, and the flower pollination algorithm is used to improve the inversion accuracy and computational efficiency. Finally, the applicability, feasibility, advantages and disadvantages of the improved four-dimensional variation algorithm are verified by numerical simulation analysis. It is found that the improved four-dimensional variation algorithm can realize the source term inversion under three conditions: the location is known and the intensity is unknown, the intensity is known and the location is unknown, the intensity and the location are all unknown, which the accuracy and computational efficiency can basically meet the actual needs.

Flow distortion effect on electromagnetic flowmeter and mitigation using magnetic flux manipulation

The effect of velocity profile distortion on the performance of flow sensors like the electromagnetic flowmeter has been a popular topic in flow measurement research. In many of the investigations computational modeling has been useful as a tool to understand the impact of flow distortion on flowmeter measurement accuracy. However, a more realistic investigation can be conducted by a model with ability to account for three-dimensional variation in fluidic and electromagnetic characteristics. In this research paper, a multiphysics model of the Electromagnetic flowmeter accounting for three-dimensional flow distortion effects and independent of experimental measurements is developed and validated. The model integrates the flow and magnetic fields to yield the induced electrical signal, and is a departure from the popular weight function calculation approach. The model predicts flow distortion effects realistically and is employed in evaluating an idea to mitigate flow distortion problems: manipulating the magnetic field to minimize distortion effects. It is seen that while flow distortion induces a 3 to 4 % error in a flowmeter designed arbitrarily, proper design of the coils can reduce this error to an insignificant level.

A Probabilistic Approach for Three-Dimensional Variation Analysis in Aero-engine Rotors Assembly

Rotor assembly is a core tache in the whole process of aero-engine manufacturing. Preventing out-of-tolerance of concentricity is one of the primary tasks. Conventional assembly approaches are based on a manual test with the dial indicator, depending on experience appraises, which lack systematic and quantitative precision design theory. As a result, two issues need to be solved: the modeling problem of complicated geometric variations in three-dimensions, as well as the abnormal distribution of ubiquitous actual deviations. This work attempts to propose a novel probabilistic approach for three-dimensional variation analysis in rotor assembly. Based on rotor’s revolving characteristics and multistage stacking process, Jacobian–Torsor model is adopted to establish the variation propagation, and Pearson distribution family is used to derive the probability density function, which can quickly determine the variation distribution pattern and efficiently perform statistical variation analysis. A real case of mechanical assemblies consisting of revolving axisymmetric components is concerned. The results show that the suggested method has a similar accuracy, but much higher efficiency than conventional methods. Calculations agree with the experimentations, and the probability distribution type of the part’s variation has an appreciable impact on the final assembly precision.