Optimization of short-haul aircraft schedule recovery problems using a hybrid multiobjective genetic algorithm

https://doi.org/10.1016/j.eswa.2009.07.068Get rights and content

Abstract

A hybrid multiobjective genetic algorithm is presented in this paper to find an efficient solution for the daily short-haul aircraft schedule recovery problems which usually happen due to some disturbance events and require a time-sensitive solution to meet various hard constraints and soft objectives. The proposed algorithm employs an adaptive evaluated vector (AEV) to guide the solution search and uses the method of inequality-based multiobjective genetic algorithm to provide the multiobjective solution. A simulated disturbance experiment, temporal airport closure, is made and shown that the hybrid method can provide a very efficient short-haul schedule recovery solution under various performance indices.

Introduction

Aircraft schedule recovery problems arise when the original flight plan is disrupted by various occasional events, e.g. severe weather and mechanical problems, and should be rescheduled by delaying certain flights, swapping aircraft or taking other actions to minimize the negative effects. The operation coordinators who manage the daily airline situations have to carefully consider the practical conditions and try to make a suitable plan to narrow down the disturbance impact. Usually, a practical trade-off should be considered among the decision criteria (Luo & Yu, 1998) such as minimizing the number of delayed flights, minimizing the maximum delay, minimizing the total passenger delay, and so on. The difficulty for solving most of them is NP-complete, that is, no polynomial algorithms exist for the solutions.

Most studies for this kind of recovery problems only solve the objectives (or criteria) one by one or propagate a linear-sum on objectives to convert them into the single one. For example, Arguello, Jonathan, and Gang (1997) provided a greedy randomized adaptive search procedure (GRASP) which uses a randomized neighborhood search technique to reconstruct aircraft routings. Gu and Chung (1999) used a genetic algorithm to search the extra minimum delay time on the gate reassignments. Rosenberger, Johnson, and Nemhauser (2003) provided a set-packing model and solve it by an aircraft selection heuristic (ASH) method. Andersson (2006) presents two meta-heuristics, a tabu search and a simulated annealing approach, to solve the recovery problems efficiently. However, the single objective solution can not reflect the true cases with practical multiobjective needs, as stated by Fieldsend and Singh (2005).

Multiobjective evolutionary algorithms with global search capabilities have been successfully applied in aircraft schedule planning cases (Adachi et al., 2004, Chou et al., 2008). But, there are very few literature to study the multiobjective optimization problems of the aircraft schedule recovery. Although Lee, Lee, and Tan (2007) ever considered the schedule recovery problem under disturbance as a multiobjective optimization problem, and developed a multiobjective genetic algorithm (MOGA) to improve the robustness and operational cost of an existing flight schedule based on a simulation tool, SIMAIR 2.0, however, this approach consumes quite long computation time and may mainly be applicable for monthly schedules according to their conclusion. Clearly, it can not suit the short-haul recovery problems which require a short-time response in the daily work.

Summing up the above statements and reasons, the purpose of this paper is to formulate the daily short-haul recovery problems into multiobjective combinational optimization equations, and to develop a hybrid evolutionary algorithm which employs an adaptive evaluated vector (AEV) to guide the solution search and uses the method of inequality-based multiobjective genetic algorithm (MMGA) for globally searching for the Pareto solutions with regard to the performance. Besides, a simulated disturbance experiment, temporal airport closure, is made to validate the proposed approach.

Section snippets

Problem definition and formulation

The aircraft schedule recovery problem considered in this paper contains several hard and soft constraints. Flight connection is the main hard constraint which ensures the arrival airport does not have conflicts with the next flight departure airport. Turn-around period is another hard constraint which requests the legal minimization time gap between two adjacent flights of an aircraft. In addition, the soft constraints can be formulated into objectives which contain the minimal total delay

Solution by using hybrid MMGA (HMMGA)

Genetic algorithms, first introduced by Holland (Holland, 1975), were later improved by many researchers (Leung and Wang, 2001, Tsai et al., 2004) to serve as the global explorer for the single objective (Tsai, Chou, & Liu, 2006) or multiobjective optimization problems. For most well-designed multiobjective genetic algorithms (Chou et al., 2008, Deb et al., 2002, Horn et al., 1994, Zitzler and Thiele, 1999), Pareto-based or similar scenario guides the search for the variety and tries to explore

HMMGA algorithm

The flow chart of the hybrid algorithm is summarized in Fig. 1. Just like the general multiobjective genetic algorithm (MOGA), the evolutionary population should be operated by iterations through initialization, fitness computation, multiobjective evaluation, crossover to generate offspring, mutation and selection for elimination. However, the method used to measure objectives differs greatly from the general MOGA.

Case study

In this study, a larger disturbance event, airport temporal closure in the afternoon due to bad weather (which usually happens in the summer in Taiwan), is simulated by directly assigning a disruption time period on the flight schedule. The simulated scenario from a practice expects to prioritize the total flight delay time objective first and then measure the other objectives. This makes the recovery problem become more complex containing hard constraints, one prioritized objective and four

Experimental results

The customized parameters are chosen through repeating experiments for good performance: population size 100, off-spring size 80, crosser rate 1.0, mutation rate 0.3, and AEV separation ratio 0.8. For the hardware and software environment, the specifications are an Intel P4 3.2G CPU, 1G memory, XP SP2 OS and Dev-C++4.9.9.2 complier.

Conclusions

Aircraft recovery problems usually involve many practical objectives and should be solved within the short time limitations. Most multiobjective evolutionary algorithms mainly search for the Pareto solutions prior to considering performance constraints. Such methods may not fit the practical recovery needs especially when the response time is required to be short enough. Hence, a hybrid multiobjective genetic algorithm is proposed in this paper to provide an optimal or sub-optimal recovery

Acknowledgement

This work was supported by the National Science Council, Taiwan, Republic of China, under Grant numbers NSC 96-2221-E-327-027, NSC 96-2221-E-327-005-MY2, and NSC 96-2628-E-327-004-MY3.

References (21)

  • L.H. Lee et al.

    A multiobjective genetic algorithm for robust flight scheduling using simulation

    European Journal of Operational Research

    (2007)
  • N. Adachi et al.

    Application of genetic algorithm to flight schedule planning

    Systems and Computers in Japan

    (2004)
  • T. Andersson

    Solving the flight perturbation problem with meta heuristics

    Journal of Heuristics

    (2006)
  • M.F. Arguello et al.

    A grasp for aircraft routing in response to groundings and delays

    Journal of Combinatorial Optimization

    (1997)
  • Baker, J. E. (1987). Reducing bias and inefficiency in the selection algorithm. In Proceedings of the second...
  • T.Y. Chou et al.

    Method of inequality-based multiobjective genetic algorithm for domestic daily aircraft routing

    IEEE Transaction on System, Man, Cybernetic, Part A

    (2008)
  • K. Deb et al.

    A fast and elitist multiobjective genetic algorithm: NSGA-II

    IEEE Transaction on Evolution Computation

    (2002)
  • J.E. Fieldsend et al.

    Pareto evolutionary neural networks

    IEEE Transaction on Neural Network

    (2005)
  • D.E. Goldberg

    Genetic algorithms in search optimization & machine learning

    (1989)
  • Grefenstette, J., Gopal, R., Rosimaita, B., & Gucht, D. V. (1985). Genetic algorithms for the traveling salesman...
There are more references available in the full text version of this article.

Cited by (24)

  • The aircraft recovery problem: A systematic literature review

    2023, EURO Journal on Transportation and Logistics
  • A reinforcement learning approach for multi-fleet aircraft recovery under airline disruption

    2022, Applied Soft Computing
    Citation Excerpt :

    These assumptions were used to reflect the situation that aircraft operation is disrupted by airport closures. In addition, several studies also adopted these assumptions to simplify the problem [39,43]. We added Assumptions (11) and (12) for the following three reasons.

  • Airline disruption management: A literature review and practical challenges

    2021, Computers and Operations Research
    Citation Excerpt :

    Here the model is tested on data from China Airlines. Liu et al. (2010) presented a hybrid heuristic that combined an adaptive evaluated vector (AEV) and an inequality-based multi-objective genetic algorithm (GA) formulation that was used to search for Pareto solutions to the daily short-haul recovery problems. The AEV was used to guide the search and the GA was to provide the multi-objective solution.

  • Multiple objective solution approaches for aircraft rerouting under the disruption of multi-aircraft

    2017, Expert Systems with Applications
    Citation Excerpt :

    But, there are very few literatures to study the multi-objective optimization problems of the aircraft schedule recovery. Liu, Chen, and Chou (2010) constructed a multi-objective combinational optimization model formulation for daily short-haul recovery problems, and developed a hybrid evolutionary algorithm composed of an adaptive evaluated vector and the method of inequality-based multi-objective genetic algorithm. A simulated disturbance experiment of daily domestic airline plans in Taiwan with only 7 aircraft and 39 flights was tested.

View all citing articles on Scopus
View full text