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The fractal geometry of fitness landscapes at the local optima level

Journal Article

Thomson, S. L., Ochoa, G., & Verel, S. (2022)

The fractal geometry of fitness landscapes at the local optima level. Natural Computing, 21(2), 317-333. https://doi.org/10.1007/s11047-020-09834-y

A local optima network (LON) encodes local optima connectivity in the fitness landscape of a combinatorial optimisation problem. Recently, LONs have been studied for their fra...

Inferring Future Landscapes: Sampling the Local Optima Level

Journal Article

Thomson, S. L., Ochoa, G., Verel, S., & Veerapen, N. (2020)

Inferring Future Landscapes: Sampling the Local Optima Level. Evolutionary Computation, 28(4), 621-641. https://doi.org/10.1162/evco_a_00271

Connection patterns among Local Optima Networks (LONs) can inform heuristic design for optimisation. LON research has predominantly required complete enumeration of a fitness ...

The Local Optima Level in Chemotherapy Schedule Optimisation

Presentation / Conference Contribution

Thomson, S. L., & Ochoa, G. (2020, April)

The Local Optima Level in Chemotherapy Schedule Optimisation. Presented at EvoCOP 2020: Evolutionary Computation in Combinatorial Optimization, Seville, Spain

In this paper a multi-drug Chemotherapy Schedule Optimisation Problem (CSOP) is subject to Local Optima Network (LON) analysis. LONs capture global patterns in fitness landsca...

Clarifying the Difference in Local Optima Network Sampling Algorithms

Presentation / Conference Contribution

Thomson, S. L., Ochoa, G., & Verel, S. (2019, April)

Clarifying the Difference in Local Optima Network Sampling Algorithms. Presented at 19th European Conference, EvoCOP 2019, Leipzig, Germany

We conduct the first ever statistical comparison between two Local Optima Network (LON) sampling algorithms. These methodologies attempt to capture the connectivity in the loc...

Multifractality and dimensional determinism in local optima networks

Presentation / Conference Contribution

Thomson, S. L., Verel, S., Ochoa, G., Veerapen, N., & Cairns, D. (2018, July)

Multifractality and dimensional determinism in local optima networks. Presented at GECCO '18: Genetic and Evolutionary Computation Conference, Kyoto, Japan

We conduct a study of local optima networks (LONs) in a search space using fractal dimensions. The fractal dimension (FD) of these networks is a complexity index which assigns...

On the Fractal Nature of Local Optima Networks

Presentation / Conference Contribution

Thomson, S. L., Verel, S., Ochoa, G., Veerapen, N., & McMenemy, P. (2018, April)

On the Fractal Nature of Local Optima Networks. Presented at 18th European Conference: EvoCOP 2018, Parma, Italy

A Local Optima Network represents fitness landscape connectivity within the space of local optima as a mathematical graph. In certain other complex networks or graphs there ha...

The effect of landscape funnels in QAPLIB instances

Presentation / Conference Contribution

Thomson, S. L., Ochoa, G., Daolio, F., & Veerapen, N. (2017, July)

The effect of landscape funnels in QAPLIB instances. Presented at GECCO '17: Genetic and Evolutionary Computation Conference, Berlin, Germany

The effectiveness of common metaheuristics on combinatorial optimisation problems can be limited by certain characteristics of the fitness landscape. We use the local optima n...

Comparing communities of optima with funnels in combinatorial fitness landscapes

Presentation / Conference Contribution

Thomson, S. L., Daolio, F., & Ochoa, G. (2017, July)

Comparing communities of optima with funnels in combinatorial fitness landscapes. Presented at GECCO '17: Genetic and Evolutionary Computation Conference, Berlin, Germany

The existence of sub-optimal funnels in combinatorial fitness landscapes has been linked to search difficulty. The exact nature of these structures --- and how commonly they a...