“…The assessment of the workload intensity induced by complexity factors has mainly been done by asking the subjective personal opinion of controllers [149], by observing controllers at work and measuring the time they spend on various actions [150] or by measuring their physiological parameters [151]. Finally, regression techniques, which can be simple linear [57,152] or logistic regression [153] as well as more developed methods, such as neural networks [154][155][156], are used to find the function that best fits the relationship between the sector capacity and the complexity factors. Once this function is defined, it can be used to estimated the sector capacity under targeted traffic situations subject to the workload intensity threshold.…”