Preprocessing the Discrete Time-Cost Tradeoff Problem with Generalized Precedence Relations

Abstract

This study investigates the deadline of the discrete time-cost tradeoff problem (DTCTP-D) with generalized precedence relations (GPRs). This problem requires modes to be assigned to the activities of a project such that the total cost is minimized and the total completion time and the precedence constraints are satisfied. Anomalies under GPRs are irreconcilable with many current theories and methods. We propose a preprocessing technology, an equivalent simplification approach, which is an effective method for solving large-scale complex problems. We first study a way to deal with the anomalies under GPRs, such as the reduce (increase) in project completion as a consequence of prolonging (shortening) an activity, and discover relationships between time floats and path lengths. Then, based on the theories, we transform the simplification into a time float problem and design a polynomial algorithm. We perform the simplification and improve the efficiency of the solution by deleting redundant calculation objects.

Non-dominated NSGA-II genetic algorithm for schedule acceleration considering the discrete time-cost compensation problem (DTCTP) in a construction project

“…In this case, the activity duration is a discrete, nonincreasing function of the amount of the single nonrenewable resource assigned. So, each activity can be executed in a limited number of time-cost alternatives, so-called modes, for each activity, according to all possible resource allocations (Wei, Su and Zhang, 2020)an equivalent simplification approach, which is an effective method for solving large-scale complex problems. We first study a way to deal with the anomalies under GPRs, such as the reduce (increase, (Wglarz et al, 2011).…”

“…According to (Wei, Su and Zhang, 2020) there are three solution orientations in literature. The orientation may be focused on the deadline, budget or efficiency between time-cost solutions over the set of feasible durations.…”