| Goal: |
To do challenging, innovative research or advanced development in
imaging/graphics/visualization, web search, compression, advanced
user interfaces, or related areas, preferably in a Unix/Linux or
cross-platform environment.
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| Education: |
University of Chicago |
University of Minnesota |
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Ph.D., Physics
(Radial Motions in Spiral Galaxies)
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B.S., Physics |
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M.S., Physics |
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B.S., Astrophysics |
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B.S., Mathematics |
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| Experience: |
Yahoo! |
Sunnyvale, CA |
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Member of Technical Staff ("Technical Yahoo!") on core
runtime search-engine team,
September 2004 to present. Rewrote core "results presentation"
code to provide more intelligent and relevant
summaries of web pages returned as users' search results; profiled
and optimized code; managed search-engine releases and database
performance-testing on rotating basis; helped monitor and debug
"unusual behavior," such as specific types of hardware failure or
unusual cluster latency; documented evolving design of
summarization component and of overall search engine; etc.
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Philips Semiconductors |
San Jose, CA |
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Software Architect and Research/Development Engineer, June 2001 to
September 2004.
- 2004: Helped create embedded-Linux SDK for triple-core
(MIPS + two DSPs) processor, to support digital video and
audio applications.
- 2003-2004: Ported interprocessor-communication (IPC)
module of internal SDE to triple-core, dual-OS
processor; unified host RPC support across VxWorks, Windows,
and Linux; added VxWorks protected-memory extensions.
- 2001-2002: Part of new innovation
and strategy group for home networking and
consumer-electronics architectures, with special emphasis
on Linux-based gateways and set-top boxes. Led development
of first Linux distribution for dual-core (MIPS + VLIW DSP)
processor and helped isolate and fix several toolchain,
kernel, and hardware bugs.
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Philips Research |
Sunnyvale, CA |
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Member of Technical Staff, August 1995 to April 1996; Senior MTS,
April 1996 to May 2001.
- Context browser, 2001: Began researching novel
techniques for managing large stores of text, images, audio
and video clips, Web bookmarks, appointment and scheduling
data, and ordinary computer files, with particular emphasis
on useful and natural navigation via a handheld (PDA) or a
webpad. Filed for several patents, including US 7,047,500. (Research group was terminated before
more than a single, very limited prototype was completed.)
- Reliable Home Server, 1998-2000: Developed Linux-based
prototypes for
home networking, including remote home monitoring with a
standard web browser or wireless Palm via multiple cameras;
remote control of home lighting and electronic devices (e.g.,
programming of legacy VCR via the Web); event (motion)
detection and extended image-archiving; Universal Plug and
Play (UPnP) support with bridging to a 1394-based networking
standard; automated, electronic photo-album support; and
standard gateway, firewall, file-serving, and audio playback
functions. Helped shape corporate policy on Linux.
- Virtual CD Jukebox, 1998: Optimized MP3 and AAC codecs
for eventual use in advanced digital audio product (similar to
AudioReQuest); technical lead on software
architecture of first prototype.
- Virtual communities, 1997: Investigated graphical
level-of-detail algorithms, scalability of virtual worlds,
and user-interface issues for 3D navigation. Designed
virtual motion controller to allow omnidirectional walking or
running within a virtual environment without harm (US 6,270,414); filed
additional patents on low-cost methods for creating 3D models
(e.g., US 6,765,572).
Developed efficient techniques for the generation, storage,
caching and dynamic, web-based display of a moderately large
(230,000 images, 200 GB uncompressed), CGI-driven,
multi-resolution map.
- "GOLD" image format, 1996: Researched image
compression and display technologies for use over
low-bandwidth channels, and co-developed a very fast,
compact, hybrid image format for proxy-mediated use over
such links (US 6,128,021). Combination of early, high-resolution
monochrome layer and low-resolution color layer provided
significantly quicker legibility of embedded text, and
subsequent two-pass line-interlacing scheme with deflate
compression reconstructed original image losslessly, with
almost no additional size penalty over GIF or PNG.
- Internet TV, 1995: Created WebTV-like prototype
(independent of but concurrent with efforts by WebTV, then
known as Artemis Research) using modified X Mosaic; added
support for progressive display, external control via
tcl/tk "remote," next-link/previous-link capability, etc.,
during first two months with Philips.
In addition, mentored summer intern and managed part of jukebox
project. Maintained numerous internal web pages, both local and
worldwide, plus external AlphaWorld (virtual world) map site for
seven years.
Edited bimonthly Silicon Valley news mailing for upper and middle
management, and authored various internal technical notes and white
papers. Prior to joining as a researcher, performed Unix system
administration (SunOS, Linux) for three years.
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Open-source developer |
(Internet) |
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Shareware, open-source, and free/libre software developer, 1985 to
present.
- PNG Development Group, since 1995: Founding member
of group to define, implement, and standardize (IETF, later
ISO/IEC) a patent-free, lossless replacement for the GIF
image format. Created (and still
maintain) official Portable Network Graphics and
Multiple-image
Network Graphics home sites; wrote PNG: The
Definitive Guide (O'Reilly, June 1999) and PNG
chapter of the Lossless Compression Handbook (Academic
Press, December 2002); wrote and/or contributed to numerous
PNG-supporting programs (see Software below).
- Info-ZIP, 1990-2004: Helped create and distribute
portable, free compressor/archiver utilities. Contributed to
Zip; led development of UnZip for eight years; maintained web site for
more than ten.
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Additionally, research experience at the University of Chicago and
NASA Ames (simulation and visualization software, including a
doubly iterative fitting program for galactic dynamics,
a 2.5-dimensional gravitational hydrodynamics code,
and particle dynamics codes),
AT&T Bell Labs, Argonne National Laboratory, and Fermilab
(summers); teaching experience (electronics, modern physics,
electromagnetism, freshman physics); and
excellent technical-writing skills (see Publications below).
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| Patents: |
Issued:
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- Dynamically Configurable Virtual Window Manager,
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G. Roelofs;
filed November 2001,
issued May 2006
(US 7,047,500).
- Apparatus and System for Abstract Visual
Representation of Audio Signals
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G. Roelofs;
filed September 2001,
issued August 2005
(US 6,937,211).
- Virtual [Elephant] Modeling by Shadow-cast
Voxel-clipping
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G. Roelofs;
filed April 2001,
issued July 2004
(US 6,765,572).
- Compensating for Network Latency in a Multi-player
Game
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G. Roelofs;
filed March 2001,
issued November 2002
(US 6,475,090).
- Exoskeletal Platform for Controlling Multi-Directional
Avatar Kinetics in a Virtual Environment
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G. Roelofs;
filed December 1997,
issued August 2001
(US 6,270,414)
and December 2002
(EP 0 974 087 B1).
- Downloading Image Graphics with
Accelerated Text Character and Line Art Creation
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P. v. d. Meulen and G. Roelofs;
filed October 1996,
issued October 2000
(US 6,128,021).
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Pending:
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Force-Mediated [Font] Rasterization,
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G. Roelofs;
filed September 2001.
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Nonlinear Display Method for Data of Infinite Extent,
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G. Roelofs;
filed August 2001.
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Security System Simulates Patterns of
Usage of Appliances,
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G. Roelofs;
filed June 2001.
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System and Method for Remote Control of Consumer
Electronics over Data Network with Visual Feedback,
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G. Roelofs and P. v. d. Meulen;
filed June 2001.
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Advanced Path Checker,
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P. v. d. Meulen and G. Roelofs;
filed March 2001.
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Virtual Model Generation via Physical Components,
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G. Roelofs;
filed February 2001.
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GUI has Library Metaphor Based on
Non-Euclidean Geometry,
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G. Roelofs;
filed November 2000.
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Handheld Retrieves UI from Server for
Controlling Apparatus via Server,
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R. Sagar and G. Roelofs;
filed April 2000.
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Half a dozen additional disclosures ranging from novel
user interfaces to micromachines (MEMS).
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| Publications: |
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| Software: |
Primary author of pngquant (RGBA to RGBA-palette quantization and
dithering); rpng/rpng2/wpng cross-platform demo programs (Unix,
VMS, Win32);
pngsplit (PNG chunk-extraction utility);
UnZip; gpr (ASCII-to-PostScript converter); various Unix scripts
and utilities; "which" clone for OS/2; original OS/2 port of Elvis
(text editor); etc.
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Contributor to intel2gas (assembler-syntax converter),
Firefox/Mozilla/Netscape 6+, Arena, X Mosaic, libpng, gif2png,
tiff2png, pnmtopng/pngtopnm, pngcheck, XV, XPaint, giftool, Zip,
lha, unrar, check/crc, file/magic, BSD mailx, BSD uuencode/uudecode
(VMS port), hd (hex dumper), fm (hex editor), life (OS/2 screen
saver), VMS zmodem, and others.
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| Technical: |
C/C++/STL, x86 assembler, some Java and Perl,
FORTRAN, VRML; Unix/Linux and X development,
32-bit Windows, VxWorks, pSOS+,
OS/2, DOS, VMS; PC, Sun, SGI, Cray, TriMedia, MIPS, and other
hardware.
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