Hi! I'm John Callahan. You can email me at <my wiki name> at acm <dot> org. I currently work for the Applied Physics Laboratory. Previously, I was employed as CTO and Vice President of Engineering for BDMetrics, Inc., a successful portal company for the largest trade shows in North America including the Consumer Electronics Show, PackEXPO and the National Association of Broadcasters. At BDMetrics, I developed demographic algorithms and systems for marketing to over 2 million individuals through personalized web portals. Before BDMetrics, I was CTO of Sphere Software Corporation, a small Maryland company specializing in XML, data security, and healthcare informatics. Before Sphere, I was a tenured professor of Computer Science at West Virginia University from 1992-2001. At WVU, I also served as research director for the NASA Software IV&V Facility. I received my PhD in Computer Science in 1993 from the University of Maryland, College Park. During graduate school, I worked for Xerox Corporation of Palo Alto, CA and Reston, VA. I have also worked as a coop student for NASA Goddard and the Air Force Data Services Center in the Pentagon.