Metaheuristic Algorithms for Multimode Multiproject Scheduling With the Objective of Positive Cash Flow Balance

Yukang He,Jingwen Zhang,Zhengwen He

doi:10.1109/access.2019.2944746

Abstract

This paper investigates the problem of how to achieve a positive cash flow balance by multimode multiproject scheduling, in which a contractor must implement multiple projects concurrently, and activities can be performed with one of several alternative modes. First, based on formulating cash flows for the projects, we construct an optimization model that can minimize the maximum gap between accumulative cash outflow and cash inflow, thus balancing cash flow positively by arranging optimal execution modes and start times for activities. Then, we prove the NP-hardness of the studied problem and design two metaheuristic algorithms, namely, tabu search (TS) and simulated annealing (SA), which search the desirable solutions in nested and mixed ways, respectively. Finally, taking the multistart iterative improvement (MSII) as comparison algorithm, the performance of the two algorithms developed is evaluated through a computational experiment performed on a data set generated randomly. From the research results, the following conclusions are drawn. The TS and SA are more suitable for solving the smaller and larger problems, respectively, while the nested searching structure could enhance the algorithm’s efficiency. With increases in the advance payment proportion, the number of milestone activities, the client’s payment proportion, or the project deadline, the contractor’s maximal cash flow gap decreases.

Highlights

Cash flow management, which involves the forecasting, planning, monitoring, and controlling of the cash flow, is recognized as a critical issue in project management [1]
In this paper, we investigate a multimode multiproject scheduling problem to achieve a positive balance between cash outflow and inflow
This process can lead to the searching structure of the tabu search (TS) being more organized and more reasonable than that of the simulated annealing (SA), rendering the desirable solutions found by the TS better than those obtained by the SA as whole

Summary

INTRODUCTION

Cash flow management, which involves the forecasting, planning, monitoring, and controlling of the cash flow, is recognized as a critical issue in project management [1]. Through reasonable project scheduling, which includes choosing an execution mode and arranging a start time for each activity, the contractor can coordinate cash outflow and inflow effectively, achieving a positive cash flow balance. This problem is more meaningful in a multiproject context since, in practice, the contractor can implement multiple projects simultaneously [4]. Our aim is to arrange the project schedule, which consists of the execution modes and start times of activities in all of the projects, to minimize the cash flow gap so that the contractor achieves a positive balance between cash outflow and inflow.

LITERATURE REVIEW

METAHEURISTIC ALGORITHMS

TABU SEARCH

SIMULATED ANNEALING

CONCLUSION