英语语法分析

The model is formulated as a mixed integer linear programming (MILP) problem.

模型表达为一个混合整数规划(MIL P)问题。

However, it is quite difficult for the expansion of model under the MILP framework.

然而，在混合整数线性规划的框架下，模型的扩展十分困难。

At last, the thesis proves MILP model and its arithmetic-branch and bound method practicability and validity by giving an example.

最后，本文运用例子证明了混合整数线性规划及其算法-分枝定界法的实用性和有效性。