Dr Trimble's experiences and research interests include System Dynamics: philosophy, teaching tools, knowledge acquisition; Expert Systems: knowledge acquisition, instructional expert systems; Software Engineering: software quality assurance, life cycle models; Modeling and Simulation: discrete and continuous models, Stella, Extend, Arena; Knowledge Management; Curriculum development in simulation and systems thinking; Appropriate Technology and System Dynamics. He has taught, given guest lectures and consulted extensively in Africa including Rwanda, Ghana, Mauritius, Zimbabwe, South Africa and Namibia. He spent a year as a Fulbright professor in Zimbabwe in 2003-2004. Dr. Trimble is an Associate Professor in systems and computer science at Howard University, but is currently on a two year leave until 2009 to serve as Dean of Information Communication Technology at Umutara Polytechnic University (a new university in Nyagatare Rwanda). He has been extensively involved in international work on ‘appropriate technology’ including serving as the chair of the international planning committee on the first two international conferences on appropriate technology hosted in Zimbabwe in 2004 and 2006.