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Operational optimisation of water distribution networks.

Lopez-Ibanez, Manuel (2009) Operational optimisation of water distribution networks. PhD thesis, Edinburgh Napier University.

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    Abstract/Description

    Water distribution networks are a fundamental part of any modern city and their daily operations constitute a significant expenditure in terms of energy and maintenance costs.
    Careful scheduling of pump operations may lead to significant energy savings and prevent wear and tear. By means of computer simulation, an optimal schedule of pumps can
    be found by an optimisation algorithm. The subject of this thesis is the study of pump scheduling as an optimisation problem.

    New representations of pump schedules are investigated for restricting the number of potential schedules. Recombination and mutation operators are proposed, in order to use
    the new representations in evolutionary algorithms. These new representations are empirically compared to traditional representations using different network instances, one of
    them being a large and complex network from UK. By means of the new representations, the evolutionary algorithm developed during this thesis finds new best-known solutions
    for both networks.

    Pump scheduling as the multi-objective problem of minimising energy and maintenance costs in terms of Pareto optimality is also investigated in this thesis. Two alternative
    surrogate measures of maintenance cost are considered: the minimisation of the number of pump switches and the maximisation of the shortest idle time. A single run of
    the multi-objective evolutionary algorithm obtains pump schedules with lower electrical cost and lower number of pump switches than those found in the literature. Alternatively,
    schedules with very long idle times may be found with slightly higher electrical cost.

    Finally, ant colony optimisation is also adapted to the pump scheduling problem. Both Ant System and Max-Min Ant System are tested. Max-Min Ant System, in particular,
    outperforms all other algorithms in the large real-world network instance and obtains competitive results in the smallest test network. Computation time is further reduced by
    parallel simulation of pump schedules.

    Item Type: Thesis (PhD)
    Uncontrolled Keywords: Computer simulation; Water distribution networks; Optimisation algorithms; Evolutionary algorithms; Max-min ant colony simulations; Parallel simulations; Applications; Pump scheduling; Switch reduction; Maximising idling times; Cost reduction
    University Divisions/Research Centres: Faculty of Engineering, Computing and Creative Industries > School of Engineering and the Built Environment
    Dewey Decimal Subjects: 000 Computer science, information & general works > 000 Computer science, knowledge & systems > 006 Special Computer Methods
    600 Technology > 620 Engineering > 627 Hydraulic engineering
    Library of Congress Subjects: T Technology > TC Hydraulic engineering. Ocean engineering
    Q Science > QA Mathematics > QA76 Computer software
    Item ID: 3044
    Depositing User: Dr. David A. Cumming
    Date Deposited: 03 Nov 2009 17:58
    Last Modified: 12 Jan 2011 04:51
    URI: http://researchrepository.napier.ac.uk/id/eprint/3044

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