I am half of the development team behind STELLA Modeler for the iPad, responsible for much of the user experience. I have been involved in System Dynamics for the past 7 years, with a masters degree in it from the University of Bergen. I've worked on a wide variety of System Dynamics software, including STELLA/iThink, Forio Simulate, a SD activity for OLPC laptops, and my masters thesis. I was a member of the XMILE Technical Committee, helping to define a common file format for SD models. Additionally, I've been involved in software development for over a decade, and involved with open-source software for the majority of that time. For more technical details on my background, see bpowers.github.io.