Gary R. Holt

Interests

Algorithms development in a variety of fields, including:

• Video and image analysis and compression.
• Machine learning (neural networks and related statistical techniques); data mining.
• Computer vision.
• Computational biology.
• Tools for programmers.

Professional Experience

2003-present (Synopsys, Inc.)

Algorithms development for physical chip layout. I worked in clock tree synthesis, designing and implementing algorithms to optimize clock trees for skew, insertion delay, power, and area, subject to a variety of constraints. I used a variety of graph algorithms as well as some ideas from optimization theory.

2001-2002 (Pulsent Corporation)

Algorithms development for a object-based video compression codec (as opposed to the traditional block-based video codecs). I worked with wavelets, aspects of arithmetic encoding, and the JPEG2000 still image compression standard. I also developed and used algorithms that are not typical for video compression codecs, such as morphology, neural networks, and various numerical and geometric algorithms. I also worked on modifying these algorithms to be implementable in an ASIC.

Academic Research

1998-2000 (University of Southern California)

Investigated algorithms for unsupervised learning of good features for object recognition, and of object boundary detection in natural images. Also worked on improving low-level vision algorithms such as edge-detectors. (With Prof. Bartlett Mel.)

1997 (Caltech)

Analysis and simulation of the electrical fields around active neurons and the possibilities for crosstalk. For this, I developed a neuron simulator and also code to solve the Poisson equation for electrical potential in the special case of a neuron. (With Prof. Christof Koch.)

1996 (Caltech)

Analysis and simulation of biophysics of shunting inhibition and its role on neural firing rates. This analysis corrected some commonly used simplified models of neurons. (With Prof. Christof Koch and Prof. Rodney Douglas.)

1994-1996 (Caltech and Institut für Neuroinformatik, University of Zürich/ETH)

Simulation and mathematical analysis of a model of direction selectivity for cortical simple cells (with Prof. Christof Koch and Prof. Rodney Douglas).

1991-1994 (Caltech and MRC Anatomical Neuropharmacology Unit, Oxford)

Statistical (power-spectrum and other techniques) analysis of in vivo intracellular voltage traces for insight into synaptic integration and the origin of variability (with Prof. Christof Koch and Prof. Rodney Douglas).

1990-1991 (Caltech undergraduate thesis)

Modeled nonlinear cat retinal X and Y cell dynamics in response to moving stimuli (for Prof. Christof Koch)

1988-1989 (Caltech undergradate research)

Simulation of a model (unrelated to the one I analyzed in 1995-96) of direction selectivity of cortical simple cells (with Dr. Florentin Wörgötter).

Education

1991-1997

Ph. D. in Computation and Neural Systems from the California Institute of Technology. Thesis title: A Critical Reexamination of Some Assumptions and Implications of Cable Theory in Neurobiology. Advisor: Prof. Christof Koch

1987-1991

B.S. in Biology (with honors) from the California Institute of Technology.

Patents

• Method and Apparatus for Partitioning an Arbitrarily-Shaped Area. U.S. Application Number 10/062574.
• Video Interlacing Using Object Motion Estimation. U.S. Provisional Application Number 60/407390.
• Temporal Filtering Using Object Motion Estimation. U.S. Application Number 10/729834.
• Video Deinterlacing Using Object Motion Estimation. U.S. Application Number 10/646334.
• Image Deformation by Comparative Lattice Perturbation. To be filed.

Publications

• Development and Function of Spatially Invariant Feature Hierarchies for Visual Recognition. G. R. Holt and B. W. Mel. Society for Neuroscience Abstracts, 1999.
• Electrical Interactions via the Extracellular Potential Near Cell Bodies. G. R. Holt and C. Koch. Journal of Computational Neuroscience 6:169-184, 1999.
• Shunting Inhibition Does Not Act Divisively on Firing Rates. G. R. Holt and C. Koch. Neural Computation 9:1001-1013, 1997.
• A Comparison of Discharge Variability In Vitro and In Vivo in Cat Visual Cortex Neurons. G. R. Holt, W. R. Softky, R. J. Douglas, and C. Koch. J. Neurophysiol. 75:1806-1814, 1996.
• Spatiotemporal Mechanisms in Receptive Fields of Visual Cortical Simple Cells--A Model. F. Wörgötter and G. Holt, J. Neurophysiol. 65:494-510, 1991.

Computer Skills

Publically available software that I've written

makepp

A syntax-compatible reimplementation of the make program, with a number of advanced features including automatic include file scanning, vastly improved support for multiple directories, advanced signature checking algorithms to ensure reliable builds and avoid unnecessary ones, repositories, support for variant builds, etc.

seescape

An image processing environment designed for testing and evaluating new low-level vision algorithms.

matwrap

Automatic interface generator so that all member functions in one or more C++ classes can be called from matlab or a matlab clone. Does the hard work of type checking and conversion between matlab's types and the types in the C++ code.

Honors and Awards

1991-1994

National Defense Science and Engineering Graduate (NDSEG) fellowship.

1988-1991

Caltech Merit Scholarship (3 times) for academic achievement.

1987

Member, U. S. Physics Olympiad team

References

Available on request.