特别是重点研究了DOWNSIDE RISK方法中适用于所有类型偏好函数的LPM方法的运用效率，求解了VaR约束下的资产组合问题。

• Especially it focuses on the efficiency of Lower Partial Moments (LPM, one of the methods in DOWNSIDE RISK), which is applicable to all types of utility functions, and solves the portfolio problem under the VaR constraint.