What do A pos and C pos mean?
The # column is the rank of each listed entry for Zhi-Xun Shen — rank 1 means this entry is where Zhi-Xun Shen has the most articles or citations. A pos and C pos show the reciprocal: the position of Zhi-Xun Shen within that entry's own ranked list, by articles and citations respectively. A low value means Zhi-Xun Shen is among the most prominent contributors for that entry.