Computational Geometry Column 42

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

The Importance of Local Fiscal Conditions in Analyzing Local Labor Markets

A new test of the compensating wage differential model is proposed. The logic behind Roback's model showing how differences in nonproduced amenities may be reflected in intercity wage differentials is extended to the case of differences in local fiscal conditions, represented by tax rates and publicly produced services. Results show that differences in local tax rates and services provisions do generate compensating wage differentials across cities. The effects of a particularly large set of taxes and effective services output measures are examined.

On the Political Economy of Land Value Capitalization and Local Public Sector Rent-Seeking in a Tiebout Model

In this paper we examine the political economy. of capitalization in a Tiebout model when there is a rent-seeking public bureaucracy. A new approach is suggested for testing for the influence of successful local public sector rent-seeking on local property values. We present empirical evidence showing that property values are lower in cities which pay their public sector workers significantly more than similar public sector workers earn in other cities. Finally, we discuss how the regulatory process can be used to distribute rents arising from a short-run Tiebout disequilibrium to landowners, public sector workers, and renters.

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

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

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