A simple method of obtaining quasi-continuous frequency spectra of the input impedance of arterial systems

1971 ◽  
Vol 330 (3) ◽  
pp. 271-276 ◽  
Author(s):  
Th. Pasch ◽  
R. D. Bauer
Keyword(s):  
Input Impedance ◽  
Simple Method ◽  
Frequency Spectra ◽  
Continuous Frequency

scholarly journals The Relative Weight of Temporal Envelope Cues in Different Frequency Regions for Mandarin Disyllabic Word Recognition

2021 ◽  
Vol 15 ◽  
Author(s):  
Zhong Zheng ◽  
Keyi Li ◽  
Yang Guo ◽  
Xinrong Wang ◽  
Lili Xiao ◽  
...  
Keyword(s):  
Word Recognition ◽  
Relative Weight ◽  
Frequency Region ◽  
Frequency Spectra ◽  
Temporal Envelope ◽  
Hearing Devices ◽  
Disyllabic Word ◽  
Disyllabic Words ◽  
Continuous Frequency ◽  
Speech Information

ObjectivesAcoustic temporal envelope (E) cues containing speech information are distributed across all frequency spectra. To provide a theoretical basis for the signal coding of hearing devices, we examined the relative weight of E cues in different frequency regions for Mandarin disyllabic word recognition in quiet.DesignE cues were extracted from 30 continuous frequency bands within the range of 80 to 7,562 Hz using Hilbert decomposition and assigned to five frequency regions from low to high. Disyllabic word recognition of 20 normal-hearing participants were obtained using the E cues available in two, three, or four frequency regions. The relative weights of the five frequency regions were calculated using least-squares approach.ResultsParticipants correctly identified 3.13–38.13%, 27.50–83.13%, or 75.00–93.13% of words when presented with two, three, or four frequency regions, respectively. Increasing the number of frequency region combinations improved recognition scores and decreased the magnitude of the differences in scores between combinations. This suggested a synergistic effect among E cues from different frequency regions. The mean weights of E cues of frequency regions 1–5 were 0.31, 0.19, 0.26, 0.22, and 0.02, respectively.ConclusionFor Mandarin disyllabic words, E cues of frequency regions 1 (80–502 Hz) and 3 (1,022–1,913 Hz) contributed more to word recognition than other regions, while frequency region 5 (3,856–7,562) contributed little.

Statistical Analysis of Slow-Drift Responses

1983 ◽  
Vol 105 (3) ◽  
pp. 310-317 ◽  
Author(s):  
C. T. Stansberg
Keyword(s):  
Probability Density ◽  
Low Frequency ◽  
Mathematical Expression ◽  
General System ◽  
Analytical Signal ◽  
Second Order ◽  
Induced Response ◽  
Frequency Spectra ◽  
Slow Drift ◽  
Continuous Frequency

The statistical properties of second-order wave-induced response processes are investigated theoretically. Emphasis is placed on the slow-drift components. The assumed forcing waves are irregular with continuous frequency spectra. A spectral analysis of the response of a general system is made. It is shown that the slow-drift components are closely connected to the complex analytical signal and the Hilbert envelope of the wave elevation. A simple mathematical expression exists for the slow-drift components, based on the complex wave signal and the second-order impulse response of the system. By use of this explicit formula, the theoretical probability functions of slow-drift responses are investigated. The analysis is based on the Kac-Siegert method. A similar approach has earlier been applied to study the sum of both the low-frequency and the high-frequency second-order responses. Final calculations of the probability density functions are in general very complicated, but it can be simplified by the use of a simple idealized model for the second-order transfer function. Probability density curves for a few simple cases are presented.

The transition from steady to weakly turbulent flow in a close-packed ordered array of spheres

2002 ◽  
Vol 465 ◽  
pp. 59-97 ◽  
Author(s):  
REGHAN J. HILL ◽  
DONALD L. KOCH
Keyword(s):  
Hopf Bifurcation ◽  
Geometrical Structure ◽  
Reynolds Numbers ◽  
Frequency Spectra ◽  
Chaotic Flow ◽  
Fundamental Frequencies ◽  
Lattice Boltzmann Simulations ◽  
Ordered Array ◽  
Flow Changes ◽  
Continuous Frequency

The sequence of transitions in going from steady to unsteady chaotic flow in a close-packed face-centred cubic array of spheres is examined using lattice-Boltzmann simulations. The transition to unsteady flow occurs via a supercritical Hopf bifurcation in which only the streamwise component of the spatially averaged velocity fluctuates and certain reflectional symmetries are broken. At larger Reynolds numbers, the cross-stream components of the spatially averaged velocity fluctuate with frequencies that are incommensurate with those of the streamwise component. This transition is accompanied by the breaking of rotational symmetries that persisted through the Hopf bifurcation. The resulting trajectories in the spatially averaged velocity phase space are quasi-periodic. At larger Reynolds numbers, the fluctuations are chaotic, having continuous frequency spectra with no easily identified fundamental frequencies. Visualizations of the unsteady flows in various dynamic states show that vortices are produced in which the velocity and vorticity are closely aligned. With increasing Reynolds number, the geometrical structure of the flow changes from one that is dominated by extension and shear to one in which the streamlines are helical. A mechanism for the dynamics is proposed in which energy is transferred to smaller scales by the dynamic interaction of vortices sustained by the underlying time-averaged flow.

Asymmetrically Respiratory System Simulation for Identifying Airway Occlusion

2001 ◽  
Author(s):  
A. M. Al-Jumaily ◽  
Y. Al-Fakhri
Keyword(s):  
Theoretical Model ◽  
Dynamic Characteristic ◽  
Respiratory System ◽  
Input Impedance ◽  
System Simulation ◽  
Acoustic Response ◽  
Frequency Spectra ◽  
Airway Occlusion ◽  
Airway Walls ◽  
The Impact

Abstract A theoretical model is developed to investigate the dynamic characteristic of a healthy and an occluded asymmetric respiratory system. The model takes the elastance and inertance of the airway walls into consideration. Frequency spectra of the input impedance determined at the throat are generated and examined for two regimes of airway terminations and for occlusion at each generation from the end terminal (alveolar sacs) up to the proximal end of the trachea. In the asymmetric arrangement the impact of merging dissimilar flows due to different airways geometry from the adjacent regions is considered. Further, the effect of the nature of the terminal impedance (ie. rigid termination or compliant termination) on the acoustic response is also investigated.

A simple way for producing holographic filters suitable for image improvement

1978 ◽  
Vol 36 (1) ◽  
pp. 226-227
Author(s):  
K.-H. Herrmann ◽  
E. Reuber ◽  
P. Schiske
Keyword(s):  
Transfer Functions ◽  
Diffraction Order ◽  
Lateral Position ◽  
Simple Method ◽  
Spatial Frequencies ◽  
Resolution Electron ◽  
Wiener Filters ◽  
Image Improvement ◽  
Optical Reconstruction ◽  
Set Up

Aposteriori deblurring of high resolution electron micrographs of weak phase objects can be performed by holographic filters [1,2] which are arranged in the Fourier domain of a light-optical reconstruction set-up. According to the diffraction efficiency and the lateral position of the grating structure, the filters permit adjustment of the amplitudes and phases of the spatial frequencies in the image which is obtained in the first diffraction order.In the case of bright field imaging with axial illumination, the Contrast Transfer Functions (CTF) are oscillating, but real. For different imageforming conditions and several signal-to-noise ratios an extensive set of Wiener-filters should be available. A simple method of producing such filters by only photographic and mechanical means will be described here.A transparent master grating with 6.25 lines/mm and 160 mm diameter was produced by a high precision computer plotter. It is photographed through a rotating mask, plotted by a standard plotter.

Rotary Beveling for In Situ Thin-Section Microscopy of Cell Cultures

1981 ◽  
Vol 39 ◽  
pp. 550-551
Author(s):  
Dean A. Handley ◽  
Jack T. Alexander ◽  
Shu Chien
Keyword(s):  
Cell Growth ◽  
Cell Cultures ◽  
Molecular Interactions ◽  
Convenient Method ◽  
Petri Dish ◽  
Simple Method ◽  
Thin Section Microscopy ◽  
Thin Sectioning ◽  
Organic Fluids

In situ preparation of cell cultures for ultrastructural investigations is a convenient method by which fixation, dehydration and embedment are carried out in the culture petri dish. The in situ method offers the advantage of preserving the native orientation of cell-cell interactions, junctional regions and overlapping configurations. In order to section after embedment, the petri dish is usually separated from the polymerized resin by either differential cryo-contraction or solvation in organic fluids. The remaining resin block must be re-embedded before sectioning. Although removal of the petri dish may not disrupt the native cellular geometry, it does sacrifice what is now recognized as an important characteristic of cell growth: cell-substratum molecular interactions. To preserve the topographic cell-substratum relationship, we developed a simple method of tapered rotary beveling to reduce the petri dish thickness to a dimension suitable for direct thin sectioning.

Development of a simple method for the determination of single nucleotide polymorphisms

2010 ◽  
Vol 34 (8) ◽  
pp. S75-S75
Author(s):  
Weifeng Zhu ◽  
Zhuoqi Liu ◽  
Daya Luo ◽  
Xinyao Wu ◽  
Fusheng Wan
Keyword(s):  
Single Nucleotide Polymorphisms ◽  
Nucleotide Polymorphisms ◽  
Simple Method ◽  
Single Nucleotide
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