Yusuf Pisan and Andrew Bachmann
A significant amount of research has been done in solving static engineering problems. Dynamic problems, where at least one of the parameters of the system is changing, pose a larger challenge that has only been addressed in part by previous work. We describe two new qualitative reasoning techniques that we use to solve additional problems. In the first technique, we use qualitative reasoning to determine when parameters stay constant between states, which allows us to eliminate variables from equations. This is useful in solving problems that have partial information and require information to be shared between different states in order to simplify equations. In the second technique, we use a guided attainable envisionment to determine which equations are applicable in a particular state and to guide calculations using these equations. This technique helps to solve problems that require the use of different equations in different states. In some situations, the envisionment also allows us to conclude some simplifying modeling assumptions. We also describe how to use quantitative information from the problem solver to focus this envisionment and prevent state explosion.