A key policy measure introduced by governments worldwide at the beginning of the coronavirus disease 2019 (COVID-19) pandemic was to restrict travel, highlighting the importance of people's mobility as one of the key contributors to spreading severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). …

This paper seeks to highlight underlying issues of the tourism system that have led to tourism extremes of too much or too little tourism. Five phases are recognized that reflect different ways of dealing with too much tourism over time, after which the impact of a sudden lack of tourism is investigated …

In this thesis, we develop mathematical models for the optimal deployment of security forces addressing two main challenges: adaptive behavior of the adversary and uncertainty in the model. We address several security applications and model them as agent-intruder games. The agent represents the security …