Birthdate: June 8, 1951
Place of Birth: Claysburg, PA
Citizenship: U.S.
Theses: Employment: Organization Membership: Awards and Fellowships:

Professional Statement of Dennis M. Freeman

Biological transducers

Biological transducers exploit physical mechanisms that are very different from those used in man-made transducers. Cells employ a class of membrane-bound proteins called ion-channels to perform transduction processes. My research is aimed at determining how these molecular components are organized into a system: the inner ear. Understanding the signal processing techniques used by sensory cells in the inner ear holds promise to inspire new engineering strategies, including the possibility of designing man-made systems that exploit cellular components. New techniques in molecular biology are rapidly changing the way we think about biological structures --- from the products of evolution to components that we can design and mass produce. We may one day be able to build signal-processing systems using components that are similar to those that nature has used for millions of years.

Measurements of nanometer motions of small structures

To understand the system properties of the inner ear, one must know how the components move and interact. We've developed video methods to image these small (micrometer) structures and image processing methods to estimate the even smaller (nanometer) motions from video sequences. Although designed to measure motions of inner ear structures, the system is more generally useful. We have also applied the system to characterize motions of man-made micro-electro-mechanical systems. Furthermore, the motion estimation algorithms are of general use in machine vision applications.

Theoretical and computational hydrodynamics

Concurrent with our experimental research, we are developing analytical and computational models of inner ear mechanics. The mathematically most complicated parts of the models are the interactions of structures with the surrounding fluid. We are developing boundary element methods that can be used to efficiently account for hydrodynamic effects. Although developed for understanding fluid motions in the inner ear, the methods are more generally applicable, and we are investigating applications to man-made micro-electro-mechanical systems.

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