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Mixed gravitational centrality (Wang, Li and Xia 2018), also called improved gravitational centrality, uses the core number \(k_s(i)\) of the focal node and the degree \(k(j)\) of each partner node as masses: $$MGC_i = k_s(i) \sum_{j : 0 < d(i,j) \le r} \frac{k(j)}{d(i,j)^2}.$$

Usage

centrality_mixed_gravity(x, gravity_radius = 3, ...)

Arguments

x

Network input accepted by centrality.

gravity_radius

Hop-distance cutoff \(r\). Default 3. NULL or Inf includes every reachable node, and a value below one gives zero scores.

...

Further arguments to centrality, such as normalized (divide by the maximum, default FALSE).

Value

A named numeric vector with one score per node, in input node order.

Details

The measure is computed on the simple undirected skeleton of the network, so direction, weights, loops and parallel edges are ignored, and gravity_mass has no effect. The implementation follows the reproduction of the method in Li and Huang (2022), equations 5-8. The Centrality Zoo writes the inner sum over immediate neighbors, which corresponds to gravity_radius = 1. Isolated nodes score zero, and unreachable nodes contribute nothing. gravity_radius = "auto" is a cograph heuristic that rounds half the mean finite distance to the nearest integer, with a minimum of one. A negative radius raises an error.

References

Wang, J., Li, C. and Xia, C. (2018). Improved centrality indicators to characterize the nodal spreading capability in complex networks. Applied Mathematics and Computation, 334, 388-400. doi:10.1016/j.amc.2018.04.028 .

Li, Z. and Huang, X. (2022). Identifying influential spreaders by gravity model considering multi-characteristics of nodes. Scientific Reports, 12, 9879. doi:10.1038/s41598-022-14005-3 .

Examples

centrality_mixed_gravity(regulation_net)
#>    Explore       Plan    Monitor      Adapt    Reflect    Discuss Synthesize 
#>        130        144        158        141        127        133        122 
#>   Evaluate     Create      Share 
#>        139        147        139