Most approaches to multi-project scheduling are based on the assumption that resources can be transferred between projects without any expense in time and cost. As this assumption often is not realistic, we generalise the multi-project scheduling problem (RCMPSP) by additionally including transfer times and cost. To integrate this aspect, in a first step, we develop a framework for considering resource transfers in single and multi-project environments. It includes managerial approaches to handle resource transfers, a classification of resource transfer types and new roles that resources can take in these transfers. Afterwards, we define the multi-project scheduling problem with transfer times (RCMPSPTT) and formulate it in a basic and an extended version as integer linear programmes. Eventually, it is supplemented for the first time by cost considerations and introduced as resource constrained multi-project scheduling problem with transfer times and cost (RCMPSPTTC). Computational experiments compare the presented managerial approaches and prove the necessity of explicitly considering transfer times in project scheduling. Moreover, the experiments evaluate the presented MIP models and show that specialised solution procedures are vital.

Managing and modelling general resource transfers in (multi-)project scheduling

The operations on the aircraft carrier flight deck are carried out in a time-critical and resource-constrained environment with uncertainty, and it is of great significance to optimize the makespan and obtain a robust schedule and resource allocation plan for a greater sortie generation capacity and better operational management of an aircraft carrier. In this paper, a proactive robust optimization method for flight deck scheduling with stochastic operation durations is proposed. Firstly, an operation on node-flow (OONF) network is adopted to model the precedence relationships of multi-aircraft operations, and resource constraints categorized into personnel, support equipment, workstation space, and supply resource are taken into consideration. On this basis, a mathematical model of the robust scheduling problem for flight deck operation (RSPFDO) is established, and the goal is to maximize the probability of completing within the limitative makespan (PCLM) and minimize the weighted sum of expected makespan and variance of makespan (IRM). Then, in terms of proactive planning, both serial and parallel schedule generation schemes for baseline schedule and robust personnel allocation scheme and equipment allocation adjustment scheme for resource allocation are designed. In terms of executing schedules, an RSPFDO-oriented preconstraint scheduling policy (CPC) is proposed. To optimize the baseline schedule and resource allocation, a hybrid teaching-learning-based optimization (HTLBO) algorithm is designed which integrates differential evolution operators, peak crossover operator, and learning-automata-based adaptive variable neighborhood search strategy. Simulation results shows that the HTLBO algorithm outperforms both some other state-of-the-art algorithms for deterministic cases and some existing algorithms for stochastic project scheduling, and the robustness of the flight deck operations can be improved with the proposed resource allocation schemes and CPC policy.

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A Proactive Robust Scheduling Method for Aircraft Carrier Flight Deck Operations with Stochastic Durations

In the recent decades, the recognition that uncertainty lies at the heart of modern project management has induced considerable research efforts on robust project scheduling for dealing with uncert...

The integration of resource allocation and time buffering for bi-objective robust project scheduling

A robustness measure is an effective tool to evaluate the anti-interference capacity of the construction schedule. However, most research focuses on solution robustness or quality robustness, and few consider a composite robustness criterion, neglecting the bounded rationality of subjective weights and inherent importance and nonlinear intercriteria correlations of objective weights. Therefore, a construction schedule robustness measure based on improved prospect theory and the Copula-criteria importance through intercriteria correlation (CRITIC) method is proposed. Firstly, a composite robustness criterion is established, including start time deviation rs and structural deviation rp for measuring solution robustness from project execution and completion probability rc for measuring quality robustness from the project result. Secondly, bounded rationality is considered, using prospect theory to calculate subjective weights, which is improved by the interval distance formula. Thirdly, the Copula-CRITIC method is proposed to determine objective weights incorporating both inherent importance and nonlinear intercriteria correlations. Finally, an information-entropy-based evidence reasoning method is applied to combine subjective and objective weights together while identifying their validity. An underground power station in China is used for a case study, whose robustness is measured using the proposed methods, single robustness criterion, and composite robustness criterion using traditional weighting methods. The comparison results verify the consistency, representativeness, and advantage of the proposed criterion and methods.

A Construction Schedule Robustness Measure Based on Improved Prospect Theory and the Copula-CRITIC Method

The sortie and recovery operations of the carrier-based aircraft fleet are carried out in a cyclic mode, and there are uncertainties during the flight deck operations, which is the main factor that influences the sustainability of cyclic operations. The robust scheduling problem for flight deck operations (RSPFDO) with uncertain duration is studied in this paper. First, the robust scheduling model of flight deck operations with ternary interval durations is established. In this model, the precedence and resource constraints including personnel, equipment, workstation space, and supply resource are taken into account, and the uncertain duration is modeled as a ternary interval number. Second, to make a proactive plan, serial schedule generation scheme is used to generate baseline schedules, and a robust personnel allocation scheme is designed. In terms of executing schedules, a pre-constrained scheduling policy is proposed to evaluate the ternary interval of makespan. Third, a double-population and self-adaptive differential evolution (DSDE) algorithm is presented to optimize the robust plan, which is embedded in a population-based double justification scheme, self-adaptive selection of mutation and crossover factors, and a chaotic catastrophe operator based on the scouts mode of artificial bee colony algorithm. The validity of the established model and the superiority of the DSDE algorithm are verified by simulations with mission cases and algorithm comparison. The results demonstrate that the proposed robust scheduling method can effectively improve the robustness of the flight deck operations.

A Robust Scheduling Optimization Method for Flight Deck Operations of Aircraft Carrier With Ternary Interval Durations

The research object in this paper is the sub network formed by the predecessor’s affect on the solution activity. This paper is to study three types of influencing factors from the predecessors that lead to the delay of starting time of the solution activity on the longest path, and to analyze the influence degree on the delay of the solution activity’s starting time from different types of factors. On this basis, through the comprehensive analysis of various factors that influence the solution activity, this paper proposes a metric that is used to evaluate the solution robustness of the project scheduling, and this metric is taken as the optimization goal. This paper also adopts the iterative process to design a scattered buffer heuristics algorithm based on the robust scheduling of the time buffer. At the same time, the resource flow network is introduced in this algorithm, using the tabu search algorithm to solve baseline scheduling. For the generation of resource flow network in the baseline scheduling, this algorithm designs a resource allocation algorithm with the maximum use of the precedence relations. Finally, the algorithm proposed in this paper and some other algorithms in previous literature are taken into the simulation experiment; under the comparative analysis, the experimental results show that the algorithm proposed in this paper is reasonable and feasible.

Project Robust Scheduling Based on the Scattered Buffer Technology

The research of project scheduling based on resource flow network provides a new approach for studying project scheduling. And the stability of resource flow network also directly affects the perfo...

Yingling Shi

Papers

Project Robust Scheduling Based on the Scattered Buffer Technology

Resource flow network generation algorithm in robust project scheduling