A题问题，急！！！

mumupcl

<>第2问题中  A time dependent covariance matrix Cov(ij,kl) is typically used to quantify such a time-varying correlation relationship, in which i, j, k, and l represent the two nodes of two links.如果i,j代表节点，k,l代表什么意思呢？</P>

qkun8226

<>朱老师那里去了？</P>

zhudy

k、l也代表节点，因此kl代表一条路段。