Stephan Wehner
2150 Adanac Street
Vancouver, B.C. V5L 2E7, Canada
Tel.: (604) 767-7415
E-mail: stephan AT


A senior software developer with decades of experience in Python, Ruby, Java, online payments processing, scientific computation, image processing, mapping, and databases. Expert in Web applications.

Skills and Qualifications

Internet Technologies:
Ruby on Rails, Payment processing, Social Media, Google Maps, HTML/CSS/Javascript, XML, Apache, Nginx, SMTP, TCP, Secure Sockets (HTTPS), letsencrypt, wikis, oauth.
Database Systems:
Mysql, Postgres, SQLite .
Programming Languages:
Ruby, PHP, Java, Javascript, C, C++, Perl, Matlab, Maple, octave.
Computational Mathematics:
Time-dependent partial differential equations, scheduling, solution of sparse linear systems, search heuristics, valuation of financial derivative instruments.

Selected Professional Experience

  • Senior Software Developer, The Buckmaster Institute, Inc. Vancouver (2006 – present)
    Various web applications, based on Ruby on Rails. Online payment processing, cryptography, social media, mathematics, mapping, online games, machine learning.
  • Team Lead & Analyst, SITA INC Canada, Inc., Vancouver (2001 – 2006)
    The Vancouver office of SITA produces a range of software products for fare management within the airline industry. I was responsible for WebLogic/Oracle/Swing based 3-tier J2EE applications and MQSeries systems for importing external feeds. Full product life-cycle, from functional specification, implementation and unit testing/QA, to production deployment and support. Code refactoring. HTTP servlets to synchronize databases via XML. Mentoring of junior developers.
  • Senior Analyst & Software Developer, Applied Financial Technology, San Francisco (2000 – 2001)
    Applied Financial Technology offers a suite of mortgage prepayments and option pricing models to the financial industry. As part of the software team, I improved the existing core (C++) libraries. I created a state-of-the-art computation server based on Java Swing, RMI and JNI including a graphical user interface. Ported AFT’s Windows/Solaris based libraries to the Linux platform.
  • Internet Consultant,, Vancouver & MITACS, Vancouver, (1999-2000)
    • is a portal which connects users with advertisers promotional internet games. I developed’s user tracking management system and the online voting facility. I wrote the Perl CGI scripts and SQL database interface.
    • MITACS is the Canadian Centre of Excellence in the mathematical sciences. I created the website for the MITACS 2000 Annual General Meeting from content delivered by MITACS headquarters. I designed the necessary graphics and wrote CGI scripts for attendee’s registration.
  • Optimization Consultant & Developer, School of Computing Science, Simon Fraser University, Burnaby, (1996-1997, 1999-2000)
    • The Optimization Group of the School of Computing Science provides the Vancouver International Film Festival with a scheduling system. I developed scheduling algorithms to generate the midday schedules and to be able to quickly perform last-minute changes to the schedule. I implemented these in Visual C++ and created a user-friendly interface in Visual Basic.
    • The School of Computing Science also collaborates with Stemsoft Software. Stemsoft is interested in providing a scheduling system for health facilities staff. I delivered Functional Analysis and Project Analysis documents. I developed a scheduling algorithm and implemented the search heuristics in C++.
  • Mathematical Software Developer, Centre for Experimental and Constructive Mathematics, Simon Fraser University, Burnaby & Department of Chemistry, University of British Columbia, Vancouver, (1996, 1997 – 1999)
    • The CECM is a mathematical research centre which heavily uses modern computer resources. I designed a method to estimate the run-time of a procedure symbolically in terms of its numerical parameters and implemented it in the programming language Maple for Maple procedures. I wrote basic parser functions for translating Maple programs into C and FORTRAN. I improved a graphical user interface for SGI workstations based on the Forms and XForms libraries (in C) and adapted it to the WWW (using CGI scripts)
    • Prof. Lionel Harrison worked extensively on biological growth processes. One of his ambitions was to develop a 3D mathematical model for the growth of Micrasterias algae. He completed work on the 2D model. For the 3D case I devised and implemented a numerical method for solving reaction-diffusion equations on arbitrary surfaces (in C). I refined earlier methods to model surface growth, and wrote customized 2D and 3D-display routines for producing images in Postscript and on a Silicon Graphics workstation.
  • Embedded Software Engineer Gesellschaft fur Automation und Datentechnik (GAD), Heidelberg, Germany & Embedded Spaces Inc., Vancouver (1991, 1997)
    Both GAD and Embedded Spaces specialize in embedded systems and software development.

    • I developed an emulation of an IBM 3279 terminal in collaboration with the hardware team. I programmed the interface with a UART M68652 MPCC in 68000-Assembler and the higher levels of the communication protocol in C.
    • I implemented, according to Embedded Spaces’ specifications and coding standard, low-level data access functions for a real-time database application, and a parser for translating database definition files into internal representation from which C-code is generated. (All programs in C)


  • Ph.D. 1995, Department of Mathematics and Statistics, Simon Fraser University, Burnaby, Canada
  • Diplom Informatiker (equiv, M.Sc.) 1991, Department of Computing Science, Universitat Karlsruhe (TH), Karlsruhe, Germany
  • Mathematik Vordiplom (equiv, B.Sc.) 1989, Department of Mathematics, Universitat Karlsruhe (TH), Karlsruhe, Germany
  • Informatik Vordiplom (equiv, B.Sc.) 1988, Department of Computing Science, Universitat Karlsruhe (TH), Karlsruhe, Germany

Selected Publications

  • Enumerations, Countable Structures and Turing Degrees, Proceedings of the American Mathematical Society, July 1998
  • On recursive enumerability with finite repetitions, Journal of Symbolic Logic, Volume 64, Number 3, 1999
  •, a website dedicated to John Conway’s challenging thrackle problem
  • Traffic Life: Passionate Tales and Exit Strategies, Vancouver, 2004. A book about/against car culture

Mathematical journal articles are available at

Community Involvement



Available on request.