Discrete-Fourier-Transform-Based Evaluation of Physiological Measures as Workload Indicators : A Human-in-the-loop Study linking Workload and Fatigue in a Multi Remote Tower Environment

We propose a new approach to evaluate ocular measurements of air traffic controllers (ATCOs) as potential workload and fatigue indicators. We employ the Fast Fourier transform (FFT) to test our assumption that humans respond to increasing fatigue with harmonic oscillations in the eye movement, while they respond to increasingly high workload with disruptions to these harmonic oscillations. The FFT yields the frequency spectrum and we suggest to use the center of gravity of this spectrum to capture the variations. We give a proof-of concept study to evaluate our approach and we were able to verify our hypotheses in some cases, in particular, we identify the fixation duration as a promising indicator of changes in workload.