It is difficult to search the best projectionpoint of two dimension, but it can be solved by transforming a nonlinear optimization question.
应用该法的关键在于寻求二维空间的最佳投影点，这可以转化为一个复杂的非线性优化问题来进行解决。
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The paper USES it to evaluate petroleum enterprises, and gives the satisfactory projectionpoint by suitable weights, which can provide acceptable target to the manager.
One is the saddle-type structure where the projectionpoint is located either in the up part or the down part of the phase plane, which is divided by both stable and unstable manifolds.