In the first part of the velocity update formula (Eq. ( )), the particle's previous velocity is taken into account. Here, the particle performs an inertial motion depending on its own velocity and the inertial weight parameter ω. The second part is related to the distance between the particle's personal best position x p,i and its current location x k-1 i . This "cognitive" element represents the particle's own thinking based on its individual experience and is controlled by the cognitive acceleration factor φ p (or cognitive learning factor). The third part forms the "social" element and depends on the distance between the global best position x g and the current particle location x k-1 i