Developing an Agent Model of a Missing Person in the Wilderness

In this paper, we consider the problem of developing a model of the behaviour of a Missing Person (MP) who is lost in the wilderness. Traditional models have treated the movement of an MP as a type of diffusion process, without regard for the MP´s internal state or goals. However, this fails to include many important factors, including the effects of fatigue or the use of reorienting strategies, which are known to be important from empirical studies of actual lost person behaviour. To overcome these limitations, we develop a novel agent-based model of MP behaviour. This model incorporates the effects of the environment, perception and goals on the MP´s movement and uses them to model the continuous switching of short and medium term goals by missing people. To validate the model, we compared the trajectories simulated by it with actual recordings of movements of participants in an unfamiliar wilderness environment. By comparing the predicted and actual trajectories, we show that the generated trajectories much more faithfully represent the actual movements of the participants than state-of-the-art diffusion models.