Using Graph Theory to Assess the Interaction between Cerebral Function, Brain Hemodynamics, and Systemic Variables in Premature Infants

Figure 4

Method used to tune the kernel bandwidth σ. In (a), the data is segmented in nonoverlapping signal segments of 15 minutes. For all of these segments, a kernel matrix Ω _l is computed using a predefined σ_gs (4). All the individual kernel matrices Ω _l are concatenated in Ω _C, which is depicted in (b). Next, the Shannon entropy of Ω _C is computed. This procedure is repeated for a range of σ values. The σ value associated with maximal is selected as the bandwidth for the kernel function.