Ant Colony Hyper-heuristics for Graph Colouring Nam Pham ASAP Group, Computer Science School University of Nottingham
Nam Pham Overview Hyper-heuristic Framework Problem Description Hyper-heuristic design for the problem An ant colony hyper-heuristic approach and experimental results Future works
Nam Pham Hyper-heuristic “Heuristics that choose heuristics” High level heuristics: Meta-heuristics Choice Function Ant Algorithm Case-based Reasoning … Low level heuristics: different moving strategies, constructive heuristics …
Nam Pham Hyper-heuristic Framework
Nam Pham Graph Colouring Problem Assignment of “colours” to vertices in a graph Adjacent vertices have different colours Objective: minimise the number of required colours
Nam Pham Hyper-heuristic Design Constructive hyper-heuristics Search for sequence of heuristics [Ross 2002] Each heuristic is applied for colouring one vertex Evaluation function is defined as the number of required colours when applying heuristic sequence
Nam Pham Graph Example Heuristic 1 (H1) Heuristic 2 (H2) Heuristic 3 (H3)
Nam Pham Search Space of Heuristic Sequences We are looking for a heuristic sequence that produces smallest number of used colours Decisions H 1 H 2 H 3 Sequence
Nam Pham Ant Colony Hyper-heuristics Ant algorithms are well-known if used as low level heuristics There are only two papers using ant algorithms as hyper-heuristics so far (reference at the end)
Nam Pham Ant Colony Hyper-heuristics Ant algorithm is well-known if used as a low level heuristic There are only two papers using ant algorithm as hyper-heuristic so far (reference at the end)
Nam Pham Ant Colony Hyper-heuristics Ant algorithm is well-known if used as a low level heuristic There are only two papers using ant algorithm as hyper-heuristic so far (reference at the end)
Nam Pham Ant Colony Hyper-heuristics Ant algorithm is well-known if used as a low level heuristic There are only two papers using ant algorithm as hyper-heuristic so far (reference at the end)
Nam Pham Experiment Heuristics employed include: Largest Degree First (LD) Largest Colour Degree First (LCD) Least Saturation Degree First (SD) University of Toronto Benchmark Data ftp://ftp.mie.utoronto.ca/pub/carter/testprob ftp://ftp.mie.utoronto.ca/pub/carter/testprob
Nam Pham Results LDLCDSDAnt Algorithm HHBest known Car Car Ear Hec Kfu Lse Pur Rye Sta8313 Tre Uta Ute9210 Yor
Nam Pham Future works Compare ant colony hyper-heuristic with other population based hyper-heuristics – evolutionary algorithms, genetic algorithm, swarm intelligence… Do research on characteristics of heuristic search space Expand to exam timetabling problem
Nam Pham Reference Burke, E.K., Kendall, G., Landa Silva, J.D., O'Brien, R.F.J., Soubeiga, E.: An ant algorithm hyperheuristic for the project presentation scheduling problem. Cuesta-Cañada, A., Garrido, L., Terashima-Marín, H.: Building Hyper-heuristics Through Ant Colony Optimization for the 2D Bin Packing Problem.