A data mining application of the incidence semirings
- Authors: Abawajy, Jemal , Kelarev, Andrei , Yearwood, John , Turville, Christopher
- Date: 2013
- Type: Text , Journal article
- Relation: Houston Journal of Mathematics Vol. 39, no. 4 (2013), p. 1083-1093
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Full Text: false
- Reviewed:
- Description: This paper is devoted to a combinatorial problem for incidence semirings, which can be viewed as sets of polynomials over graphs, where the edges are the unknowns and the coefficients are taken from a semiring. The construction of incidence rings is very well known and has many useful applications. The present article is devoted to a novel application of the more general incidence semirings. Recent research on data mining has motivated the investigation of the sets of centroids that have largest weights in semiring constructions. These sets are valuable for the design of centroid-based classification systems, or classifiers, as well as for the design of multiple classifiers combining several individual classifiers. Our article gives a complete description of all sets of centroids with the largest weight in incidence semirings.
An algorithm for minimization of pumping costs in water distribution systems using a novel approach to pump scheduling
- Authors: Bagirov, Adil , Barton, Andrew , Mala-Jetmarova, Helena , Al Nuaimat, Alia , Ahmed, S. T. , Sultanova, Nargiz , Yearwood, John
- Date: 2013
- Type: Text , Journal article
- Relation: Mathematical and Computer Modelling Vol. 57, no. 3-4 (2013), p. 873-886
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Full Text: false
- Reviewed:
- Description: The operation of a water distribution system is a complex task which involves scheduling of pumps, regulating water levels of storages, and providing satisfactory water quality to customers at required flow and pressure. Pump scheduling is one of the most important tasks of the operation of a water distribution system as it represents the major part of its operating costs. In this paper, a novel approach for modeling of explicit pump scheduling to minimize energy consumption by pumps is introduced which uses the pump start/end run times as continuous variables, and binary integer variables to describe the pump status at the beginning of the scheduling period. This is different from other approaches where binary integer variables for each hour are typically used, which is considered very impractical from an operational perspective. The problem is formulated as a mixed integer nonlinear programming problem, and a new algorithm is developed for its solution. This algorithm is based on the combination of the grid search with the Hooke-Jeeves pattern search method. The performance of the algorithm is evaluated using literature test problems applying the hydraulic simulation model EPANet. © 2012 Elsevier Ltd.
- Description: 2003010583
Optimal rees matrix constructions for analysis of data
- Authors: Kelarev, Andrei , Yearwood, John , Zi, Lifang
- Date: 2012
- Type: Text , Journal article
- Relation: Journal of the Australian Mathematical Society Vol. 92, no. 3 (2012), p. 357-366
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Relation: http://purl.org/au-research/grants/arc/DP0211866
- Full Text:
- Reviewed:
- Description: Abstract We introduce a new construction involving Rees matrix semigroups and max-plus algebras that is very convenient for generating sets of centroids. We describe completely all optimal sets of centroids for all Rees matrix semigroups without any restrictions on the sandwich matrices. © 2013 Australian Mathematical Publishing Association Inc.
- Description: 2003010862
Impact of water-quality conditions in source reservoirs on the optimal operation of a regional multiquality water-distribution system
- Authors: Mala-Jetmarova, Helena , Barton, Andrew , Bagirov, Adil
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Water Resources Planning and Management Vol. 141, no. 10 (2015), p.1-14
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Full Text: false
- Reviewed:
- Description: The impact of water quality conditions in source reservoirs on the optimal operation of a regional multiquality water-distribution system is analyzed. The optimization model concurrently minimizes three operational objectives being pump energy costs, turbidity, and salinity deviations at customer demand nodes from allowed values. The optimization problem is solved using the optimization tool GANetXL incorporating the NSGA-II, linked with the network analysis software EPANet. The example network adapted from the literature captures some of the unique features of the Wimmera Mallee Pipeline in Australia. Six scenarios representing different water quality conditions in source reservoirs are analyzed. It was discovered that two types of trade-offs, competing and noncompeting, exist between the objectives and that the type of trade-off is not unique between a particular pair of objectives for all scenarios. These and other findings may be of particular use to system operators in their long-term operational planning and decision making. (C) 2015 American Society of Civil Engineers.
Exploration of the trade-offs between water quality and pumping costs in optimal operation of regional multiquality water distribution systems
- Authors: Mala-Jetmarova, Helena , Barton, Andrew , Bagirov, Adil
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Water Resources Planning and Management Vol. 141, no. 6 (2015), p. 1-16
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Full Text: false
- Reviewed:
- Description: This paper explores the trade-offs between water quality and pumping costs objectives in optimization of operation of regional multiquality water distribution systems. The optimization model is designed to concurrently minimize each objective, where water quality is represented by the deviations of constituent concentrations from required values and pumping costs are represented by energy consumed by the pumps. The optimization problem is solved using an optimization software, incorporating the nondominated sorting genetic algorithm II (NSGA-II), linked with network analysis software. Two typical but purposefully different example networks are used. First, a network with multiple water sources of different qualities and second, a network with one water source only, which was converted to represent a regional nondrinking water distribution system. The trade-offs between water quality and pumping costs are explored using a total of 14 scenarios reflecting different water quality configurations of these networks. Those scenarios, into which time variability was introduced for both source water quality and customer water quality requirements, were systematically developed to represent real-life situations that could be found in practice. The results indicate that for the majority of the scenarios, there is a trade-off with a competing nature between water quality and pumping costs objectives. Additionally, it was discovered that multiobjective optimization problems with water quality (i.e., concentration deviations) and pumping costs objectives could be reduced in certain instances into a single-objective problem of minimizing pumping costs. In fact, a regional water distribution system in which water quality is represented by a single conservative constituent can produce either a trade-off or single-objective solution between those two objectives, and this outcome is dependent on both the water quality configuration of the system and system operational flexibility. Last, some particular conclusions are drawn for both a water distribution system with multiple water sources and a water distribution system with a single water source, which suggest how changes in source water qualities or customer water quality requirements may impact system operation. It is, therefore, demonstrated that water utilities which operate regional multiquality nondrinking water distribution systems could benefit from the exploration of trade-offs between water quality and pumping costs for the purpose of operational planning.
Sensitivity of algorithm parameters and objective function scaling in multi-objective optimisation of water distribution systems
- Authors: Mala-Jetmarova, Helena , Barton, Andrew , Bagirov, Adil
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Hydroinformatics Vol. 17, no. 6 (2015), p. 891-916
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Full Text: false
- Reviewed:
- Description: This paper presents an extensive analysis of the sensitivity of multi-objective algorithm parameters and objective function scaling tested on a large number of parameter setting combinations for a water distribution system optimisation problem. The optimisation model comprises two operational objectives minimised concurrently, the pump energy costs and deviations of constituent concentrations as a water quality measure. This optimisation model is applied to a regional nondrinking water distribution system, and solved using the optimisation software GANetXL incorporating the NSGA-II linked with the network analysis software EPANet. The sensitivity analysis employs a set of performance metrics, which were designed to capture the overall quality of the computed Pareto fronts. The performance and sensitivity of NSGA-II parameters using those metrics is evaluated. The results demonstrate that NSGA-II is sensitive to different parameter settings, and unlike in the single-objective problems, a range of parameter setting combinations appears to be required to reach a Pareto front of optimal solutions. Additionally, inadequately scaled objective functions cause the NSGA-II bias towards the second objective. Lastly, the methodology for performance and sensitivity analysis may be used for calibration of algorithm parameters.
A history of water distribution systems and their optimisation
- Authors: Mala-Jetmarova, Helena , Barton, Andrew , Bagirov, Adil
- Date: 2015
- Type: Text , Journal article
- Relation: Water Science and Technology-Water Supply Vol. 15, no. 2 (2015), p. 224-235
- Relation: http://purl.org/au-research/grants/arc/LP0990908
- Full Text: false
- Reviewed:
- Description: Water distribution systems have a very long and rich history dating back to the third millennium B.C. Advances in water supply and distribution were followed in parallel by discoveries and inventions in other related fields. Therefore, it is the aim of this paper to review both the history of water distribution systems and those related fields in order to present a coherent summary of the complex multi-stranded discipline of water engineering. Related fields reviewed in this paper include devices for raising water and water pumps, water quality and water treatment, hydraulics, network analysis, and optimisation of water distribution systems. The review is brief and concise and allows the reader to quickly gain an understanding of the history and advancements of water distribution systems and analysis. Furthermore, the paper gives details of other existing publications where more information can be found.