1.lagged terms

2.the two exponential smoothing opproaches

3.the historical standard deviation approach

4.parametric

5.RiskMetrics^TM

^{6.mean squared deviation}

^{7.hybrid methods}

^{8.Multivariate density estimation (MDE)}

^{大家觉得上面8个超难的都应该是啥意思啊？咱们可以在这里比较一下，看看谁认得多，谁译得准！}