急问A题

上下求索

<>朱老师，第二问的第二小问中:Travel times on individual links are dependent on departure time, as well as are mutually correlated. A time dependent covariance matrix Cov(ij,kl) is typically used to quantify such a time-varying correlation relationship.</P>
<>mutually correlated是指谁和谁的关系？是运行时间和出发时间呢，还是各条链路之间是互相影响的？谢谢!</P>

zhudy

mutually correlated是指运行时间和运行时间的关系？不是出发时间，因为题目中明确指出运行时间是随机变量，当然这个关系是随出发时间不同而不同的。