23 research outputs found
Analysing heuristic subsequences for offline hyper-heuristic learning
This is the author accepted manuscript. The final version is available from ACM via the DOI in this recordThe paper explores the impact of sequences of search operationson the performance of an optimiser through the use of log returnsand a database of sequences. The study demonstrates that althoughthe performance of individual perturbation operators is important,understanding their performance in sequence provides greater op-portunity for performance improvements within and across opera-tions research domains
Markov Chain Selection Hyper-heuristic for the Optimisation of Constrained Magic Squares
UKCI 2015: UK Workshop on Computational Intelligence, University of Exeter, UK, 7-9 September 2015A square matrix of size n Ă— n, containing each of the numbers (1, . . . , n2) in which every row, column and both diagonals has the same total is referred to as a magic square. The problem can be formulated as an optimisation problem where the task is to minimise the deviation from the magic square constraints and is tackled here by using hyper-heuristics. Hyper-heuristics have recently attracted the attention of the artificial intelligence, operations research, engineering and computer science communities where the aim is to design and develop high level strategies as general solvers which are applicable to a range of different problem domains. There are two main types of hyper-heuristics in the literature: methodologies to select and to generate heuristics and both types of approaches search the space of heuristics rather than solutions. In this study, we describe a Markov chain selection hyper-heuristic as an effective solution methodology for optimising constrained magic squares. The empirical results show that the proposed hyper-heuristic is able to outperform the current state-of-the-art method
An analysis of heuristic subsequences for offline hyper-heuristic learning
This is the final version. Available on open access from Springer Verlag via the DOI in this recordA selection hyper-heuristic is used to minimise the objective functions
of a well-known set of benchmark problems. The resulting sequences of
low level heuristic selections and objective function values are used to generate a database of heuristic selections. The sequences in the database are
broken down into subsequences and the mathematical concept of a logarithmic return is used to discriminate between “effective” subsequences,
which tend to decrease the objective value, and “disruptive” subsequences,
which tend to increase the objective value. These subsequences are then
employed in a sequenced based hyper-heuristic and evaluated on an unseen set of benchmark problems. Empirical results demonstrate that the
“effective” subsequences perform significantly better than the “disruptive” subsequences across a number of problem domains with 99% confidence. The identification of subsequences of heuristic selections that can
be shown to be effective across a number of problems or problem domains
could have important implications for the design of future sequence based
hyper-heuristics
Multi-objective pipe smoothing genetic algorithm for water distribution network design
Session S6-03, Special Session: Evolutionary Computing in Water Resources Planning and Management IIIThis paper describes the formulation of a Multi-objective Pipe Smoothing Genetic Algorithm (MOPSGA) and its application to the least cost water distribution network design problem. Evolutionary Algorithms have been widely utilised for the optimisation of both theoretical and real-world non-linear optimisation problems, including water system design and maintenance problems. In this work we present a pipe smoothing based approach to the creation and mutation of chromosomes which utilises engineering expertise with the view to increasing the performance of the algorithm whilst promoting engineering feasibility within the population of solutions. MOPSGA is based upon the standard Non-dominated Sorting Genetic Algorithm-II (NSGA-II) and incorporates a modified population initialiser and mutation operator which directly targets elements of a network with the aim to increase network smoothness (in terms of progression from one diameter to the next) using network element awareness and an elementary heuristic. The pipe smoothing heuristic used in this algorithm is based upon a fundamental principle employed by water system engineers when designing water distribution pipe networks where the diameter of any pipe is never greater than the sum of the diameters of the pipes directly upstream resulting in the transition from large to small diameters from source to the extremities of the network. MOPSGA is assessed on a number of water distribution network benchmarks from the literature including some real-world based, large scale systems. The performance of MOPSGA is directly compared to that of NSGA-II with regard to solution quality, engineering feasibility (network smoothness) and computational efficiency. MOPSGA is shown to promote both engineering and hydraulic feasibility whilst attaining good infrastructure costs compared to NSGA-II
Artificial development of connections in SHRUTI networks using a multi-objective genetic algorithm
SHRUTI is a model of how first-order logic can be represented
and reasoned upon using a network of spiking neurons
in an attempt to model the brain’s ability to perform
reasoning. This paper extends the biological plausibility of
the SHRUTI model by presenting a genotype representation
of connections in a SHRUTI network using indirect encoding
and showing that networks represented in this way can
be generated by an evolutionary process
Interactive 3D visualisation of optimisation for water distribution systems
Session S6-03, Special Session: Evolutionary Computing in Water Resources Planning and Management IIIThis project investigates the use of modern 3D visualisation techniques to enable the interactive
analysis of water distribution systems with the aim of providing the engineer with a clear
picture of the problem and thus aid the overall design process. Water distribution systems are
complex entities that are difficult to model and optimise as they consist of many interacting
components each with a set of considerations to address, hence it is important for the engineer
to understand and assess the behaviour of the system to enable its effective design and
optimisation. This paper presents a new three-dimensional representation of pipe based water
systems and demonstrates a range of innovative methods to convey information to the user. The
system presented not only allows the engineer to visualise the various parameters of a network
but also allows the user to observe the behaviour and progress of an iterative optimisation
method. This paper contains examples of the combination of the interactive visualisation system
and an evolutionary algorithm enabling the user to track and visualise the actions of the
algorithm down to an individual pipe diameter change. It is proposed that this interactive
visualisation system will provide engineers an unprecedented view of the way in which
optimisation algorithms interact with a network model and may pave the way for greater
interaction between engineer, network and optimiser in the futur
Genetic programming for cellular automata urban inundation modelling
Session S5-02, Special Session: Computational Intelligence in Data Driven and Hybrid Models and Data Analysis IIRecent advances in Cellular Automata (CA) represent a new, computationally efficient method
of simulating flooding in urban areas. A number of recent publications in this field have shown
that CAs can be much more computationally efficient than methods that use standard shallow
water equations (Saint Venant/Navier-Stokes equations). CAs operate using local statetransition
rules that determine the progression of the flow from one cell in the grid to another
cell, and in a number of publications the Manning’s Formula is used as a simplified local state
transition rule. Through the distributed interactions of the CA, computationally simplified
urban flooding can be simulated, although these methods are limited by the approximation
represented by the Manning’s formula.
An alternative approach is to learn the state transition rule using an artificial intelligence
approach. One such approach is Genetic Programming (GP) that has the potential to be used to
optimise state transition rules to maximise accuracy and minimise computation time. In this
paper we present some preliminary findings on the use of genetic programming (GP) for
deriving these rules automatically. The experimentation compares GP-derived rules with
human created solutions based on the Manning’s formula and findings indicate that the GP
rules can improve on these approach
Evolution of connections in SHRUTI networks
SHRUTI is a model of how predicate relations can
be represented and reasoned upon using a network
of spiking neurons, attempting to model the brain’s
ability to perform reasoning using as biologically
plausible a means as possible. This paper extends
the biological plausibility of the SHRUTI model
by presenting a genotype representation of connections
in a SHRUTI network using indirect encoding
and showing that working networks represented
in this way can be produced through an evolutionary
process. A multi-objective algorithm is used
to minimise the error and the number of weight
changes that take place as a network learn
Subset-Based Ant Colony Optimisation for the Discovery of Gene-Gene Interactions in Genome Wide Association Studies
In this paper an ant colony optimisation approach for the discovery of gene-gene interactions in genome-wide association study (GWAS) data is proposed. The subset-based approach includes a novel encoding mechanism and tournament selection to analyse full scale GWAS data consisting of hundreds of thousands of variables to discover associations between combinations of small DNA changes and Type II diabetes. The method is tested on a large established database from the Wellcome Trust Case Control Consortium and is shown to discover combinations that are statistically significant and biologically relevant within reasonable computational time.The work contained in this paper was supported by an
EPSRC First Grant (EP/J007439/1).
This study makes use of data generated by the Wellcome
Trust Case Control Consortium. A full list of the inves-
tigators who contributed to the generation of the data is
available from http://www.wtccc.org.uk. Funding for the
project was provided by the Wellcome Trust under award
076113
An artificial neural network-based rainfall runoff model for improved drainage network modelling
This Presentation is brought to you for free and open access by the City College of New York at CUNY Academic Works. It has been accepted for
inclusion in International Conference on Hydroinformatics by an authorized administrator of CUNY Academic Works. For more information, please
contact [email protected]
th International Conference on Hydroinformatics
HIC 2014, New York City, USAModelling rainfall-runoff processes enables hydrologists to plan their response to flooding events. Urban drainage catchment modelling requires rainfall-runoff models as a prerequisite. In the UK, one of the main software tools used for drainage modelling is InfoWorks CS, based on relatively simple methods which are relatively robust in predicting runoff. This paper presents an alternative approach to modelling runoff that will allow for the complex inter-relation of runoff that occurs from impermeable areas, permeable areas, local surface storage and variation in rainfall induced infiltration. Apart from the uncertainties associated with the measurement of connected surfaces to the drainage system, the physical processes involved in runoff are nonlinear, making artificial neural networks (ANNs) an ideal candidate for modelling them. ANNs have been used for runoff prediction in natural catchments, and recently on a study for predicting the performance of urban drainage systems. This study seeks to determine an input set that predicts sewerage flow in urban catchments where the runoff is dominated by infiltration, a major issue for the water industry. A framework is proposed in which an ANN is trained by an evolutionary algorithm, which optimises ANN weights; results are assessed using the Nash-Sutcliffe Efficiency Coefficient. The model is demonstrated on a real-world case study site for which rainfall, flow, air temperature and groundwater levels in three boreholes have been measured. Various combinations of these data are used as model inputs, examining a mixture of daily and sub-daily timesteps. The best predictions are generated from daily linearly combined antecedent rainfall and air temperature, although sub-daily information improves the worst-case performance of the model. Although infiltration is affected by groundwater levels, incorporating groundwater into the model does not improve predictions. The proposed ANN model is capable of producing acceptable predictions, thus avoiding many of the uncertainties involved in traditional infiltration modelling