Bi-objective evacuation problem in ships or buildings

In this paper, we introduce an evacuation problem that involves several real-world evacuation elements, such as different types of evacuees and different types of exits, applicable to the evacuation of buildings or ships in emergency, e.g., fire. In particular, we exploit the multiple commodity flow in a time-expanded network to model the evacuation routes for different commodities. The commodities characterise the different types of evacuee groups which have different speeds during evacuation. We use the bi-objective programming to consider two different objectives of the evacuation planning from both time and space dimensions. Then we propose a method to solve this newly developed evacuation model. Based on a series of computational experiments and sensitivity analyses, we find that the evacuation speed of evacuees is a critical element to be considered when planning an evacuation on ships or buildings in emergency.