I regard QSIM as a kind of constraint satisfaction problem (CSP), and improve the qualitative simulation algorithm by constraint logic programming (CLP).

• 前者是将定性仿真算法看作一类约束满足问题，用约束逻辑程序加以改进，不仅为解决定性仿真问题提供了逻辑框架，而且也是一种规范化的程序描述语言；