TABLE 1.

Summary of the four considered PSN types, i.e., our proposed multi-layer PSN type and three existing single-layer PSN types. Each row (except the first) corresponds to a PSN type, and each column (except the first) outlines the corresponding PSN characteristic. Note that original PSNs differ from multi-layer PSNs in a single aspect and the two are thus fairly comparable. On the other hand, weighted PSNs and ordered PSNs differ from multi-layer PSNs in two aspects.

PSN type	Single-layer or multi-layer?	Unweighted or weighted?	Unordered or ordered?
Multi-layer	Multi-layer	Unweighted	Unordered
Original	Single-layer	Unweighted	Unordered
Weighted	Single-layer	Weighted	Unordered
Ordered	Single-layer	Unweighted	Ordered