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Patrick Stein

(formerly Patrick Fleckenstein)

5537 2nd Ave S

Minneapolis, MN 55419-1404

pat@csh.rit.edu

(612) 827-1622

Objective

I am seeking challenging full-time employment or flexible short-term contracts that will exercise and extend my skills. Jobs offering a focus in mathematics, image processing, operating systems, or networking are preferred.

Publications

Article:: LUT Filters for Quantized Processing of Signals. Ricardo L. de Queiroz and Patrick Fleckenstein. IEEE Transactions on Signal Processing, Vol. 52, pp. 687--693 (March 2004).
Article:: Signal Processing Using LUT Filters Based on Hierarchical VQ. Ricardo L. de Queiroz and Patrick Fleckenstein. Proceedings of IEEE International Conference on Acoustic, Speech, and Signal Processing, (ICASSP), SPTM-P1 (May 2001).
Article:: Very Fast JPEG Compression Using Hierarchical Vector Quantization. Ricardo L. de Queiroz and Patrick Fleckenstein. IEEE Signal Processing Letters, Vol. 7, No. 5 (May 2000).
Article:: Fast JPEG Encoding for Color Fax Using HVQ. Ricardo L. de Queiroz and Patrick Fleckenstein. Proceedings of IS&T/SPIE Symposium on Electronic Imaging, Color Imaging, San Jose (Jan 2000).

Patents

Patent 6,683,994:: HVQ-based Filtering Method. Ricardo L. de Queiroz and Patrick Fleckenstein. Issued January 27, 2004.
Patent 6,286,026:: Method and Apparatus for Integrating Pull and Push Tasks in Pipeline Data Processing. Dennis L. Venable, Patrick A. Fleckenstein, James E. Bollman. Issued September 4, 2001.
Patent 6,292,168:: Period-based Bit Conversion Method and Apparatus for Digital Image Processing. Dennis L. Venable, Patrick A. Fleckenstein, William A. Fuss. Issued September 18, 2001.

Languages and such

Use regularly: C++, C, Java, Unix shells, sed, make, PHP, JSP, XML, HTML, XSLT, CSS, and SQL.

Use occasionally: awk, perl, lex, yacc, PostScript, python, Fortran, Modula-2, COBOL, Logo, Lisp, BASIC, 8051 assembly, VAX assembly, and Motorola 68000 assembly.

Operating Systems (and hardware)

Mac OS X (Ti Book), Linux (x86), Solaris and SunOS (various), BeOS (x86), NetBSD (CCI Okee, x86, DECStation, Sparc), Ultrix (MIPS, DECStation, KIMStation, VAX), System V/88 (Motorola 88k), and Windows NT/95/3.1 (x86).

Concepts and Packages

POSIX, STL, CORBA, UML, SDL, Kerberos V, XLib, Windows MCI, threads, and sockets.

vi, CVS, LaTeX, noweb, xfig, gnuplot, gcc/g++, gdb, emacs, purify, and troff.

Computer Science & Mathematics Education

B.S. in Computational Mathematics from the Rochester Institute of Technology in Rochester, NY.

Mathematics courses include: Numerical methods, discrete mathematics, math modeling, probability, applied statistics, set theory, abstract algebra, complex variables, real variables, graph theory, game theory, number theory, differential equations, and topology.

Computer Science courses include: Data communications, data organization and management, assembly language, and digital image processing.

Work Experience

System software engineer

On this project, I am currently developing a geoimaging archive and access interface employing Google Maps, Java, and SQL.

Earlier, we integrated the various science instruments on the NASA/USRA SOFIA project and put the framework in place to allow relentless observing. I did a great deal of design work and implementation for this project in C, C++, and Java with heavy use of CORBA, XML, XSLT, JSP, and SQL.

Rochester Institute of Technology's Center for Imaging Science, Rochester, NY. 1999--present.

Computer graphics programmer

In this position, I did a wide variety of things relating to digital image processing. For the last year, I was lead programmer for our project. I received an appreciation award for work I did with a sibling group to design an API for their toolkit and another award for work I did integrating the image processing modules, communication module, and user-interface for another project. I did a great deal in this position doing image compression research, developing new image processing algorithms, creating and parsing image description languages, creating user-interfaces, integrating large-scale projects, and developing for platform-independence.

Xerox Corporation [DITC/Cadisys/Sandpiper], Rochester, NY. 1991--1995, 1996--1999.

Natural language database retrieval programmer

I hit the ground running when I joined this startup company. The company's lead product is a natural language interface to several databases (focusing on software prior art and financial advising). The system architecture is client-server with the server being composed of many separate daemons running on an arbitrary number of machines. My initial work on this product was implementing various sections of the server.

I quickly became involved in all aspects of the client-server system. I did much of the work on the communications layers in both the client and server, chunks of the user-interface, various logging and debugging mechanisms, and overall system integrity.

This project, even more so than my work at Xerox, highlighted my ability to see and work with the gestalt in a complex system. I am quite proud of this ability.

Manning and Napier Information Services, Rochester, NY. 1995--1996.

Multimedia education software programmer (PanVision)

I designed and implemented (not necessarily linearly) a programming language for the creation of multimedia applications under Windows 3.1. This software has been incorporated in several educational CD-ROMs geared toward German pre-reading-age students and in several promotional CD-ROMs.

PanVision, Essen, Germany. 1994--1996.

Advanced research group member

As a member of the Advanced Research Group at Computer Science House, I have participated in many projects. In addition to the day-to-day system administration of a network of BSD, System V, and Ultrix machines, I have worked on software for our light show, our Coke machine, and the four projects listed below.

Computer Science House, Rochester, NY. 1993--1998.

NetBSD kernel port: Two others and I (working from some sketchy documentation, the NetBSD Amiga release, and the 4.3 BSD port for the Power 6/32) ported NetBSD to the CCI Power 6/40 Okee architecture. This project involved implementing locore.s and the Okee specific device drivers. Most of the work I did on this project was in porting the device driver for the VersaBus SMD disk controller. I also assisted in debugging several device drivers and the whole of locore.

X Windows Server port: Computer Science House received a large donation from Kodak of 2-bit grayscale, high-resolution workstations. We ported the X Windows sample server to run on these machines under Ultrix. I made many modifications to the server code to get the server functioning well, including many fixes on the server side to deal with X clients that were less-than-intelligent about dealing with 2-bit displays. On this project, I learned X Windows from the inside out. I had perused Volume 0, but the rest I learned from reading the include files. I have employed this method of learning on various systems, and it has proved particularly effective for me.

Inferno DIS disassembler: I wrote a disassembler for DIS objects in C. I based it on the documentation provided on the web about the DIS virtual machine. This project was the first step toward implementing a DIS virtual machine, but my interest in this project waned before completion of the VM.

Virtual Reality network: I was a key implementer and designer in the early revisions of the Virtual Reality/Learning Systems Development project at Computer Science House. On this project, I made extensive use of socket communication under Unix and AmigaDOS.

Other Programming Activities

MN Writes (http://www.mnwrites.org/)

In less than a month of spare time, I did all of the PHP and MySQL driving the Minnesota Writes web site.

Minnesota Writes, Minneapolis, MN. 2005.

nklein software (http://www.nklein.com/)

I started the web site for the distribution of my own software projects. Most of my focus has been on software with a multi-dimensional bent. Several of these projects are highlighted below.

nklein software, Rochester, NY. 1998--present.

n-dimensional raytracing: I have developed a raytracer which supports an arbitrary number of spatial dimensions. It supports cylindrical objects (with an arbitrary number of "round" dimensions), quadratic surfaces, CSG objects, convex hulls, Coxeter polytopes, extrusions, arbitrary rotations, arbitrary scalings, JPEG output, ppm output, PostScript output, multiple light sources, directional light sources, texture-mapping, reflections, and refraction.

Clifford algebras library: I created a C++ template library for Clifford algebras and employed them to do color convolution filtering and fractal generation. I recently updated this library to allow one to do the wedge product in addition to the Clifford product.

54321: This program is five games in four-, three-, and two-dimensions for one player. This game won an honorable mention in the SDL 1MB Linux Game Programming Contest sponsored by No Starch Press, Linux Journal, and Loki Software.

DVD Tracks

I developed the entire DVD Tracks web site with PHP and MySQL in less than two weeks of my spare time. This site is no longer in use.

DVD Tracks, Minneapolis, MN. 2002--2004.

Operating systems overview seminars

I prepared and gave a two-hour presentation on the fundamental concepts of modern operating systems. This presentation was given as the introductory session of the Computer Science House Operating System Seminar Series. For this seminar, I focused mainly on how system calls differ from library calls and how the operating system arbitrates device contention. The slides I created for the presentation are available online.

Computer Science House, Rochester, NY. 1996.