Computational Geometry Column 42

A compendium of thirty previously published open problems in computational geometry is presented.Comment: 7 pages; 72 reference

Working with Constrained Systems: A Review of A. K. Joshi's IJCAI-97 Research Excellence Award Acceptance Lecture

This is a brief review of Joshi's award acceptance lecture published in <I>AI Magazine</I>. This review appeared in the AI Watch column in <I>Computers and Society</I>, a quarterly magazine

Acoustophoresis method and apparatus

A method and apparatus are provided for acoustophoresis, i.e., the separation of species via acoustic waves. An ultrasonic transducer applies an acoustic wave to one end of a sample container containing at least two species having different acoustic absorptions. The wave has a frequency tuned to or harmonized with the point of resonance of the species to be separated. This wave caused the species to be driven to an opposite end of the sample container for removal. A second ultrasonic transducer may be provided to apply a second, oppositely directed acoustic wave to prevent undesired streaming. In addition, a radio frequency tuned to the mechanical resonance and coupled with a magnetic field can serve to identify a species in a medium comprising species with similar absorption coefficients, whereby an acoustic wave having a frequency corresponding to this gyrational rate can then be applied to sweep the identified species to one end of the container for removal

Impact tolerant material

A material is protected from acoustic shock waves generated by impacting projectiles by means of a backing. The backing has an acoustic impedance that efficiently couples the acoustic energy out of the material

Partially Resolving the Tension between Omniscience and Free Will: A Mathematical Argument

We put forward a probability-based theory of temptation with implications for philosophy of religion and philosophy of mind, alike

Comparison of Raised and Flat-Seam Baseballs

The difference in seam-height between raised and flat-seam baseballs leads to different different drag and spin forces when the balls are thrown by a pitcher. The goal of this experiment is to measure the difference in vertical deflection of curveball pitches, caused by the different seam-heights