Construction imitating ants: Resource-unconstrained scheduling with artificial ants

The paper presents a methodology to arrive at critical path calculations in construction networks by imitating the natural selection processes utilized by real-life ants in search of shortest paths to a food source, and by using Ant Colony Optimization (ACO) algorithms. Ant Colony Optimization is a population-based, artificial multi-agent, general-search technique for the solution of difficult combinatorial problems with its theoretical roots based on the behavior of real ant colonies. The fundamental mathematical background of the ACO method is outlined and a suggested possible implementation strategy is described for solving for longest (critical) paths in construction schedule networks. The ACO methodology should be of interest to both researchers and practitioners since it provides an alternative method to critical path calculations, with a wide range of applications. The described ACO virtual multi-agent approach is supplemented by a sample case study as well as algorithms for the solution of resource-unconstrained construction schedules.