Figure 3.

(a) is the variable space. For example, the position vector has three dimensions, i.e., I ∈ $\left\{1,2,3\right\}$. Each dimension ${\mathit{p}}^I$ is in $\left\{1,2,3\dots ,22\right\}$ and $\left\{1,2,3\dots ,15\right\}$ for nonwearable and wearable, respectively; (b) is the illustration of a specific sensor number corresponding to the real sensor position; (c) defines the distance of each dimension between the two vectors; and (d) is the definition of the goal function and fitness value.