Speaking Rate and Speech Movement Velocity Profiles

1993 ◽  
Vol 36 (1) ◽  
pp. 41-54 ◽  
Author(s):  
Scott G. Adams ◽  
Gary Weismer ◽  
Raymond D. Kent
Keyword(s):  
Velocity Profile ◽  
Control Strategies ◽  
Velocity Profiles ◽  
Speaking Rate ◽  
Stop Consonants ◽  
Production Task ◽  
Movement Velocity ◽  
Lower Lip ◽  
X Ray ◽  
Peaked Function

The effects of speaking rate on the velocity profiles of movements of the lower lip and tongue tip during the production of stop consonants were examined using an x-ray microbeam system. Five young adults used a magnitude production task to produce five speaking rates that ranged from very fast to very slow. Results indicated that changes in speaking rate were associated with changes in the topology of the speech movement velocity-time function. Specifically, the velocity profile changed from a symmetrical, single-peaked function at the fast speaking rates to an asymmetrical and multi-peaked function at the slow speaking rates. This variation in velocity profile shape is interpreted as support for the view that alterations in speaking rate are associated with changes in motor control strategies. In particular, the control strategy for speech gestures produced at fast speaking rates appears to involve unitary movements that may be predominately preprogrammed, whereas gestures produced at slow speaking rates consist of multiple submovements that may be influenced by feedback mechanisms.

Different Predictions by the Minimum Variance and Minimum Torque-Change Models on the Skewness of Movement Velocity Profiles

2004 ◽  
Vol 16 (10) ◽  
pp. 2021-2040 ◽  
Author(s):  
Hirokazu Tanaka ◽  
Meihua Tai ◽  
Ning Qian
Keyword(s):  
Velocity Profile ◽  
Velocity Profiles ◽  
Minimum Variance ◽  
Movement Planning ◽  
System Stability ◽  
Movement Duration ◽  
Movement Velocity ◽  
Change Models ◽  
External Forces ◽  
Minimum Torque

We investigated the differences between two well-known optimization principles for understanding movement planning: the minimum variance (MV) model of Harris and Wolpert (1998) and the minimum torque change (MTC) model of Uno, Kawato, and Suzuki (1989). Both models accurately describe the properties of human reaching movements in ordinary situations (e.g., nearly straight paths and bell-shaped velocity profiles). However, we found that the two models can make very different predictions when external forces are applied or when the movement duration is increased. We considered a second-order linear system for the motor plant that has been used previously to simulate eye movements and single-joint arm movements and were able to derive analytical solutions based on the MV and MTC assumptions. With the linear plant, the MTC model predicts that the movement velocity profile should always be symmetrical, independent of the external forces and movement duration. In contrast, the MV model strongly depends on the movement duration and the system's degree of stability; the latter in turn depends on the total forces. The MV model thus predicts a skewed velocity profile under many circumstances. For example, it predicts that the peak location should be skewed toward the end of the movement when the movement duration is increased in the absence of any elastic force. It also predicts that with appropriate viscous and elastic forces applied to increase system stability, the velocity profile should be skewed toward the beginning of the movement. The velocity profiles predicted by the MV model can even show oscillations when the plant becomes highly oscillatory. Our analytical and simulation results suggest specific experiments for testing the validity of the two models.

scholarly journals The dam-break problem for concentrated suspensions of neutrally buoyant particles

2013 ◽  
Vol 724 ◽  
pp. 95-122 ◽  
Author(s):  
C. Ancey ◽  
N. Andreini ◽  
G. Epely-Chauvin
Keyword(s):  
Velocity Profile ◽  
Newtonian Fluid ◽  
Velocity Profiles ◽  
Lubrication Theory ◽  
Dam Break ◽  
Particle Migration ◽  
Flow Depth ◽  
Concentrated Suspensions ◽  
Front Position ◽  
Neutrally Buoyant

AbstractThis paper addresses the dam-break problem for particle suspensions, that is, the flow of a finite volume of suspension released suddenly down an inclined flume. We were concerned with concentrated suspensions made up of neutrally buoyant non-colloidal particles within a Newtonian fluid. Experiments were conducted over wide ranges of slope, concentration and mass. The major contributions of our experimental study are the simultaneous measurement of local flow properties far from the sidewalls (velocity profile and, with lower accuracy, particle concentration) and macroscopic features (front position, flow depth profile). To that end, the refractive index of the fluid was adapted to closely match that of the particles, enabling data acquisition up to particle volume fractions of 60 %. Particle migration resulted in the blunting of the velocity profile, in contrast to the parabolic profile observed in homogeneous Newtonian fluids. The experimental results were compared with predictions from lubrication theory and particle migration theory. For solids fractions as large as 45 %, the flow behaviour did not differ much from that of a homogeneous Newtonian fluid. More specifically, we observed that the velocity profiles were closely approximated by a parabolic form and there was little evidence of particle migration throughout the depth. For particle concentrations in the 52–56 % range, the flow depth and front position were fairly well predicted by lubrication theory, but taking a closer look at the velocity profiles revealed that particle migration had noticeable effects on the shape of the velocity profile (blunting), but had little impact on its strength, which explained why lubrication theory performed well. Particle migration theories (such as the shear-induced diffusion model) successfully captured the slow evolution of the velocity profiles. For particle concentrations in excess of 56 %, the macroscopic flow features were grossly predicted by lubrication theory (to within 20 % for the flow depth, 50 % for the front position). The flows seemed to reach a steady state, i.e. the shape of the velocity profile showed little time dependence.

scholarly journals New Infrared Diffuse Interstellar Bands in the Galactic Center and Elsewhere

2013 ◽  
Vol 9 (S297) ◽  
pp. 64-67
Author(s):  
T. R. Geballe
Keyword(s):  
Velocity Profile ◽  
Galactic Center ◽  
Velocity Profiles ◽  
Significant Fraction ◽  
Diffuse Interstellar Bands ◽  
The Galaxy ◽  
Band Spectra

AbstractThis paper updates the recent discovery of over a dozen new diffuse interstellar bands (DIBs), first in H-band spectra of stars in the Galactic center (GC) and toward stars in the Cygnus OB2 Association. The H-band DIBs, which currently number 15, are the longest wavelength DIBs reported to date and are the first found on sightlines toward the Galactic center. K-band (2.0-2.5 μm) spectra of the GC stars do not reveal additional DIBs. Comparison of the velocity profile of the strongest of the new DIBs in the sightline toward GCS3-2 (in the GC) with that toward Cygnus OB2 No. 9 and also with the broad velocity profiles of H3+ lines toward GCS3-2 confirm that a significant fraction of the diffuse material producing the DIB absorptions on sightlines to the GC is located within the central few hundred parsecs of the Galaxy.

Synthesis of Transition Metal Clusters and Their Catalytic and Optical Properties

1992 ◽  
Vol 286 ◽  
Author(s):  
J. P. Wilcoxon ◽  
A. Martino ◽  
R.L. Baughmann ◽  
E. Klavetter ◽  
A.P. Sylwester
Keyword(s):  
Optical Properties ◽  
Metal Clusters ◽  
Control Strategies ◽  
Size Control ◽  
Transition Metal Clusters ◽  
X Ray ◽  
Surfactant Aggregates ◽  
Gold Silver ◽  
Pd Clusters ◽  
Average Size

ABSTRACTMetal Clusters may be synthesized in the interior of surfactant aggregates called inverse micelles. These nanosize chemical reactors permit the controlled growth of several types of metal clusters. We describe this process for the formation of Au, Ag, Pd, Pt and Ir clusters and cluster alloys. Two size-control strategies are described: 1)variation of micelle size by alteration of the surfacant and/or solvent combination used, and 2) judicious use of micelle interactions or phase behavior. Using these two methods size control in the range of 1-100 nm is possible. The optical properties of metal clusters of gold, silver, and gold/silver alloys are described and the surface plasmon resonances are shown to have dramatic blue shifts and extensive line broadening with decreasing size in the range of 10-1 nm. In the case of gold clusters, the distinct resonancein the visible disappears for sizes less than 2.0 nm and new features appear in the UV. The optical spectra of alloys of gold and silver are shown to differ dramatically from their homoatomic counterparts of the same average size. We use electron and X-ray diffraction to determine the phase structure of the metal clusters and small angle X-ray scattering, neutron scattering, light scattering and TEM to characterize the average size and size distributions of these clusters. Finally, we describe measurements of the catalytic activity of Pd clusters and demonstrate a dramatic increase in hydrogenation activity on the size range of 2-10 nm.

Ataxic Dysarthria

1981 ◽  
Vol 46 (4) ◽  
pp. 398-404 ◽  
Author(s):  
Kathryn M. Yorkston ◽  
David R. Beukelman
Keyword(s):  
Fundamental Frequency ◽  
Rate Control ◽  
Control Strategies ◽  
Speaking Rate ◽  
Treatment Programs ◽  
Ataxic Dysarthria ◽  
Speech Performance ◽  
Oriented Research ◽  
Treatment Sequences

Treatment programs of four improving ataxic dysarthric speakers are reviewed. Treatment sequences were based on two overall measures of speech performance—intelligibility and prosody. Increases in intelligibility were initially achieved by control of speaking rate. A hierarchy of rate control strategies, ranging from a rigid imposition of rate through rhythmic cueing to self-monitored rate control is discussed. As speakers improved their monitoring skills, a compromise was made between intelligibility and rate. Normal prosodic patterns were not achieved by the ataxic speakers due to difficulty in precisely coordinating the subtle fundamental frequency, loudness and timing adjustments needed to signal stress. Three of the four subjects were taught to use only durational adjustments to signal stress. In this way, they were able to achieve stress on targeted words consistently and minimize bizarreness which resulted from sweeping changes in fundamental frequency and bursts of loudness. The need for further clinically oriented research is discussed.

Velocity Profiles of Turbulent Boundary Layers

1969 ◽  
Vol 73 (698) ◽  
pp. 143-147 ◽  
Author(s):  
M. K. Bull
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Turbulent Boundary Layer ◽  
Velocity Profile ◽  
Boundary Layers ◽  
Experimental Work ◽  
Constant Pressure ◽  
Velocity Profiles ◽  
Turbulent Boundary Layers ◽  
Boundary Layer Equations

Although a numerical solution of the turbulent boundary-layer equations has been achieved by Mellor and Gibson for equilibrium layers, there are many occasions on which it is desirable to have closed-form expressions representing the velocity profile. Probably the best known and most widely used representation of both equilibrium and non-equilibrium layers is that of Coles. However, when velocity profiles are examined in detail it becomes apparent that considerable care is necessary in applying Coles's formulation, and it seems to be worthwhile to draw attention to some of the errors and inconsistencies which may arise if care is not exercised. This will be done mainly by the consideration of experimental data. In the work on constant pressure layers, emphasis tends to fall heavily on the author's own data previously reported in ref. 1, because the details of the measurements are readily available; other experimental work is introduced where the required values can be obtained easily from the published papers.

Effect of Tapering on Pulsatile Flow Through a U-Tube Model of the Human Aortic Arch

2010 ◽  
Author(s):  
Masaru Sumida
Keyword(s):  
Velocity Profile ◽  
Pulsatile Flow ◽  
Velocity Profiles ◽  
Cross Sectional Area ◽  
Flow Rate Ratio ◽  
Sectional Area ◽  
Cross Sectional ◽  
Turn Angle ◽  
Flow Through ◽  
The Cross

An experimental investigation of pulsatile flow through a tapered U-tube was performed to study the blood flow in the aorta. The experiments were carried out in a U-tube with a curvature radius ratio of 3.5 and a 50% reduction in the cross-sectional area from the entrance to the exit of the curved section. Velocity measurements were conducted by a laser Doppler velocimetry for a Womersley number of 10, a mean Dean number of 400 and a flow rate ratio of 1. The velocity profiles for pulsatile flow in the tapered U-tube were compared with the corresponding results in a U-tube having a uniform cross-sectional area. The striking effects of the tapering on the flow are exhibited in the axial velocity profiles in the section from the latter half of the bend to the downstream tangent immediately behind the bend exit. A depression in the velocity profile appears at a smaller turn angle Ω in the case of tapering, although the magnitude of the depression relative to the cross-sectional average velocity decreases. The value of β, which indicates the uniformity in the velocity profile over the cross section, decreases with increasing Ω, whereas it rapidly increases immediately behind the bend exit.

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