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Biomedical subjects

B F Katz

Publications and source records attributed to B F Katz.

9 recordsLinked to original sources
PubMed2001

Boundary element method calculation of individual head-related transfer function. I. Rigid model calculation.

Human spatial perception of sound is a complex phenomenon. The Head-Related Transfer Function (HRTF) is a vital component to spatial sound perception. In order improve the understanding of the correlation between the HRTF and specific geometry of the head and pinna, a Boundary Element Method (BEM) has been used to calculate a portion of the HRTF of an individual based on precise geometrical data. Advantages of this approach include the ability to alter the geometry of the individual through the model in ways which are not possible with real subjects. Several models are used in the study, including a head with no pinna and several sized spheres. Calculations are performed for various source locations around the head. Results are presented for rigid model cases. Effects of variations on impedance and comparisons to measured data will be presented in the subsequent paper.

Adult↗
PubMed2001

Boundary element method calculation of individual head-related transfer function. II. Impedance effects and comparisons to real measurements.

Following previous work by the author involving the calculation of an individual head-related transfer function (HRTF) using a Boundary Element Method (BEM) approach, impedance conditions are now included to take account of the acoustic properties of human hair. In addition, comparisons are made here between calculations and measured values for the HRTF of a specific individual. Numerous works have been published regarding the measurement of HRTFs, but rarely are several methods compared for the same individual. The results presented in the work compare two different measurement techniques and a computational BEM for acquiring an individual HRTF. Impedance effects have been incorporated in the BEM model for hair based on measured data, providing a final set for comparison. Measurement results show significant variations for the same individual. Computational results show good agreement within the range of experimental variations. Definite trends are observed for many directions, while the limitations of the methods are also highlighted for others. The effects of incorporating hair impedance are shown to provide an improvement in the correlation of computational results, indicating an affect of hair impedance on the HRTF.

Acoustics↗
PubMed2000

Acoustic absorption measurement of human hair and skin within the audible frequency range.

Utilizing the two-microphone impedance tube method, the acoustic absorption of human skin and hair is measured in the frequency range 1-6 kHz. Various locations on a number of human subjects are measured to determine if the presence of bone or an air pocket affects the acoustic absorption of human skin. The absorption coefficient of human hair is also measured. Additional techniques are utilized to minimize errors due to sample mounting methods. Techniques are employed to minimize potential errors in sensor and sample locations. The results of these measurements are compared to relevant historical papers on similar investigations. Results for skin measurements compare well with previous work. Measured hair absorption data do not agree with previous work in the area but do coincide with expected trends, which previous works do not.

Absorption↗
PubMed1975

Children, privacy, and nontherapeutic experimentation.

Experimentation not for the direct benefit of the child-participant raises serious legal problems. Strict adherence to the law indicates that neither the child, parent or guardian, nor the state has the power to grant legally binding consent. A possible solution to this dilemma is suggested.

Adolescent↗