Accuracy of the NDI Wave Speech Research System

Purpose: This work provides a quantitative assessment of the positional tracking accuracy of the NDI Wave Speech Research System. Method: Three experiments were completed: (a) static rigid-body tracking across different locations in the electromagnetic field volume, (b) dynamic rigid-body tracking across different locations within the electromagnetic field volume, and (c) human jaw-movement tracking during speech. Rigid-body experiments were completed for 4 different instrumentation settings, permuting 2 electromagnetic field volume sizes with and without automated reference sensor processing. Results: Within the anthropometrically pertinent near field (\u3c 200 mm) of the NDI Wave field generator, at the 300-mm3 volume setting, 88% of dynamic positional errors were \u3c 0.5 mm and 98% were \u3c 1.0 mm. Extreme tracking errors (\u3e 2 mm) occurred within the near field for \u3c 1% of position samples. For human jaw-movement tracking, 95% of position samples had \u3c 0.5 mm errors for 9 out of 10 subjects. Conclusions: Static tracking accuracy is modestly superior to dynamic tracking accuracy. Dynamic tracking accuracy is best for the 300-mm3 field setting in the 200-mm near field. The use of automated head correction has no deleterious effect on tracking. Tracking errors for jaw movements during speech are typically \u3c 0.5 mm

Speaking Rate Effects on Normal Aspects of Articulation: Outcomes and Issues

The articulatory effects of speaking rate have been a point of focus for a substantial literature in speech science. The normal aspects of speaking rate variation have influenced theories and models of speech production and perception in the literature pertaining to both normal and disordered speech. While the body of literature pertaining to the articulatory effects of speaking rate change is reasonably large, few speaker-general outcomes have emerged. The purpose of this paper is to review outcomes of the existing literature and address problems related to the study of speaking rate that may be germane to the recurring theme that speaking rate effects are largely idiosyncratic

Arkansas Open Carry: Understanding Law Enforcement’s Legal Capability Under a Difficult Statute

“There seems to us no doubt, on the basis of both text and history, that the Second Amendment conferred an individual right to keep and bear arms.”1 Although the United States Supreme Court in District of Columbia v. Heller established a fundamental understanding that individuals have a right to own a gun for personal use, the Court recognized that, as with all fundamental rights, the individual right to keep and bear arms is “not unlimited.”2 A few limits the Court mentioned included “prohibitions on the possession of firearms by felons and the mentally ill, or laws forbidding the carrying of firearms in sensitive places such as schools and government buildings, or laws imposing conditions and qualifications on the commercial sale of arms.”3 Naturally, the Heller decision left us with this question: What are the constitutionally sound restrictions, and how far can the government go?

A polyphonic acoustic vortex and its complementary chords

Using an annular phased array of eight loudspeakers, we generate sound beams that simultaneously contain phase singularities at a number of different frequencies. These frequencies correspond to different musical notes and the singularities can be set to overlap along the beam axis, creating a polyphonic acoustic vortex. Perturbing the drive amplitudes of the speakers means that the singularities no longer overlap, each note being nulled at a slightly different lateral position, where the volume of the other notes is now nonzero. The remaining notes form a tri-note chord. We contrast this acoustic phenomenon to the optical case where the perturbation of a white light vortex leads to a spectral spatial distribution

Runway grooving project at Chicago Midway Airport

Runway grooving project at Chicago Midway Airpor

Speaking Rate Effects on Locus Equation Slope

A locus equation describes a 1st order regression fit to a scatter of vowel steady-state frequency values predicting vowel onset frequency values. Locus equation coefficients are often interpreted as indices of coarticulation. Speaking rate variations with a constant consonant–vowel form are thought to induce changes in the degree of coarticulation. In the current work, the hypothesis that locus slope is a transparent index of coarticulation is examined through the analysis of acoustic samples of large-scale, nearly continuous variations in speaking rate. Following the methodological conventions for locus equation derivation, data pooled across ten vowels yield locus equation slopes that are mostly consistent with the hypothesis that locus equations vary systematically with coarticulation. Comparable analyses between different four-vowel pools reveal variations in the locus slope range and changes in locus slope sensitivity to rate change. Analyses across rate but within vowels are substantially less consistent with the locus hypothesis. Taken together, these findings suggest that the practice of vowel pooling exerts a non-negligible influence on locus outcomes. Results are discussed within the context of articulatory accounts of locus equations and the effects of speaking rate change

Geometric phases and anholonomy for a class of chaotic classical systems

Berry's phase may be viewed as arising from the parallel transport of a quantal state around a loop in parameter space. In this Letter, the classical limit of this transport is obtained for a particular class of chaotic systems. It is shown that this ``classical parallel transport'' is anholonomic --- transport around a closed curve in parameter space does not bring a point in phase space back to itself --- and is intimately related to the Robbins-Berry classical two-form.Comment: Revtex, 11 pages, no figures