Cooperative Behaviours with Swarm Intelligence in Multirobot Systems for Safety Inspections in Underground Terrains

Table 5

A list of parameters for the ACS model.

ACO parameters	Meaning
𝛼	Pheromone influence factor
𝛽	Influence of adjacent node distance
𝜌	Pheromone evaporation coefficient
𝑄	Attractiveness constant
𝑒	Visited edge
𝑒^′	Edge not visited
𝐿𝑘	Length tour of ant k
𝜏	Pheromone concentration (amount)
𝜂	Specific visibility function (attractiveness)
Δ𝜏^𝑘	Pheromone concentration by Kth ant
𝑃𝑟(𝑖,𝑗)	Probability of moving from i to j
𝐷𝑖,𝑗	Visibility or distance between i and j
𝑓𝑖	Fitness of individual in a population
𝑃𝑖	Probability of being selected among 𝑓𝑖
𝑁	Number of individuals in the population
𝑖,𝑗	Denotes any two adjacent nodes in the graph
𝑀𝑘	Set of unvisited nodes