A ripple-spreading algorithm to calculate the k best solutions to the project time management problem

As a benchmark multi-objective optimization problem, the project management problem (PMP) usually needs to consider at least three conflicting objectives: cost, time and quality. Most existing methods can only provide an approximation of the true Pareto front to the PMP. We have recently reported an approach which can theoretically guarantee to find the complete Pareto front for discrete multi-objective problems like the PMP, while the practicability relies on the availability of effective algorithms which are capable of finding the k best solutions to each of the single-objective problems. This paper particularly focuses on how to calculate the k best solutions to the project time management problem (PTMP). To this end, a ripple-spreading algorithm is proposed, which by mimicking the natural ripple spreading phenomenon, can identify the k best ways to manage a project, so that the total project time is the shortest. The effectiveness of the proposed method is demonstrated in a comparative experiment.