GECCO '20: Proceedings of the 2020 Genetic and Evolutionary Computation Conference

GECCO '20: Proceedings of the 2020 Genetic and Evolutionary Computation Conference

Full Citation in the ACM Digital Library

SESSION: Ant colony optimization and swarm intelligence

A weighted population update rule for PACO applied to the single machine total weighted tardiness problem

  • Daniel Abitz
  • Tom Hartmann
  • Martin Middendorf

In this paper a new population update rule for population based ant colony optimization (PACO) is proposed. PACO is a well known alternative to the standard ant colony optimization algorithm. The new update rule allows to weight different parts of the solutions. PACO with the new update rule is evaluated for the example of the single machine total weighted tardiness problem (SMTWTP). This is an `NP-hard optimization problem where the aim is to schedule jobs on a single machine such that their total weighted tardiness is minimized. PACO with the new population update rule is evaluated with several benchmark instances from the OR-Library. Moreover, the impact of the weights of the jobs on the solutions in the population and on the convergence of the algorithm are analyzed experimentally. The results show that PACO with the new update rule has on average better solution quality than PACO with the standard update rule.

ACO with automatic parameter selection for a scheduling problem with a group cumulative constraint

  • Lucas Groleaz
  • Samba N. Ndiaye
  • Christine Solnon

We consider a RCPSP (resource constrained project scheduling problem), the goal of which is to schedule jobs on machines in order to minimise job tardiness. This problem comes from a real industrial application, and it requires an additional constraint which is a generalisation of the classical cumulative constraint: jobs are partitioned into groups, and the number of active groups must never exceeds a given capacity (where a group is active when some of its jobs have started while some others are not yet completed). We first study the complexity of this new constraint. Then, we describe an Ant Colony Optimisation algorithm to solve our problem, and we compare three different pheromone structures for it. We study the influence of parameters on the solving process, and show that it varies from an instance to another. Hence, we identify a subset of parameter settings with complementary strengths and weaknesses, and we use a per-instance algorithm selector in order to select the best setting for each new instance to solve. We experimentally compare our approach with a tabu search approach and an exact approach on a data set coming from our industrial application.

A multiobjective optimization approach for market timing

  • Ismail Mohamed
  • Fernando E. B. Otero

The introduction of electronic exchanges was a crucial point in history as it heralded the arrival of algorithmic trading. Designers of such systems face a number of issues, one of which is deciding when to buy or sell a given security on a financial market. Although Genetic Algorithms (GA) have been the most widely used to tackle this issue, Particle Swarm Optimization (PSO) has seen much lower adoption within the domain. In two previous works, the authors adapted PSO algorithms to tackle market timing and address the shortcomings of the previous approaches both with GA and PSO. The majority of work done to date on market timing tackled it as a single objective optimization problem, which limits its suitability to live trading as designers of such strategies will realistically pursue multiple objectives such as maximizing profits, minimizing exposure to risk and using the shortest strategies to improve execution speed. In this paper, we adapt both a GA and PSO to tackle market timing as a multiobjective optimization problem and provide an in depth discussion of our results and avenues of future research.

An approach to assess swarm intelligence algorithms based on complex networks

  • Clodomir Santana
  • Edward Keedwell
  • Ronaldo Menezes

The growing number of novel swarm-based meta-heuristics has been raising debates regarding their novelty. These algorithms often claim to be inspired by different concepts from nature but the proponents of these seldom demonstrate whether the novelty goes beyond the nature inspiration. In this work, we employed the concept of interaction networks to capture the interaction patterns that take place in algorithms during the optimisation process. The analyses of these networks reveal aspects of the algorithm such as the tendency to achieve premature convergence, population diversity, and stability. Furthermore, we make use of portrait divergence, a newly-proposed state-of-the-art metric, to assess structural similarities between our interaction networks. Using this approach to analyse the cat swarm optimization (CSO) algorithm, we were able to identify some of the algorithm's characteristics, assess the impact of one of the CSO's parameters, and compare this algorithm to two other well-known methods (particle swarm optimization and artificial bee colony). Lastly, we discuss the relationship between the interaction network and the performance of the algorithms assessed.

Exploratory path planning for mobile robots in dynamic environments with ant colony optimization

  • Valéria de C. Santos
  • Fernando E. B. Otero
  • Colin Johnson
  • Fernando S. Osório
  • Cláudio F. M. Toledo

In the path planning task for autonomous mobile robots, robots should be able to plan their trajectory to leave the start position and reach the goal, safely. There are several path planning approaches for mobile robots in the literature. Ant Colony Optimization algorithms have been investigated for this problem, giving promising results. In this paper, we propose the Max-Min Ant System for Dynamic Path Planning algorithm for the exploratory path planning task for autonomous mobile robots based on topological maps. A topological map is an environment representation whose focus is the main reference points of the environment and their connections. Based on this representation, the path can be composed by a sequence of state/actions pairs, which facilitates the navigability of the path, with no need to have the information of the complete map. The proposed algorithm was evaluated in static and dynamic environments, showing promising results in both of them. Experiments in dynamic environments show the adaptability of our proposal.