Carlo Giudicianni

Water Supply Network Partitioning Based On Weighted Spectral Clustering

Water Network Partitioning (WNP) in District Meter Area (DMA), obtained inserting remote control valves and flow meters in water supply systems, allows simplifying the water balance and pressure control in order to reduce water leakage and to improve water quality protection. Traditionally, the WNP is based on empirical suggestions and on trial and error approaches used with hydraulic simulation software, difficult to apply to large networks. Recently, some heuristic procedures, based on graph and network theory, have shown that it is possible to find optimal solutions in terms of number, shape and dimension of DMAs. In this paper, spectral clustering theory was used to define the water districts, taking into account the spatial and hydraulic constraints, through weight matrices. A comparison between different spectral clustering methods was achieved on a real water network measuring some energy performance indices, in order to identify the optimal water network partitioning.

Scaling-Laws of Flow Entropy with Topological Metrics of Water Distribution Networks

Robustness of water distribution networks is related to their connectivity and topological structure, which also affect their reliability. Flow entropy, based on Shannon’s informational entropy, has been proposed as a measure of network redundancy and adopted as a proxy of reliability in optimal network design procedures. In this paper, the scaling properties of flow entropy of water distribution networks with their size and other topological metrics are studied. To such aim, flow entropy, maximum flow entropy, link density and average path length have been evaluated for a set of 22 networks, both real and synthetic, with different size and topology. The obtained results led to identify suitable scaling laws of flow entropy and maximum flow entropy with water distribution network size, in the form of power–laws. The obtained relationships allow comparing the flow entropy of water distribution networks with different size, and provide an easy tool to define the maximum achievable entropy of a specific water distribution network. An example of application of the obtained relationships to the design of a water distribution network is provided, showing how, with a constrained multi-objective optimization procedure, a tradeoff between network cost and robustness is easily identified.

Simplified approach to water distribution system management via identification of a primary network

This is the author accepted manuscript. The final version is available from American Society of Civil Engineers via the DOI in this record.

Weighted spectral clustering for water distribution network partitioning

In order to improve the management and to better locate water losses, Water Distribution Networks can be physically divided into District Meter Areas (DMAs), inserting hydraulic devices on proper pipes and thus simplifying the control of water budget and pressure regime. Traditionally, the water network division is based on empirical suggestions and on ‘trial and error’ approaches, checking results step by step through hydraulic simulation, and so making it very difficult to apply such approaches to large networks. Recently, some heuristic procedures, based on graph and network theory, have shown that it is possible to automatically identify optimal solutions in terms of number, shape and dimension of DMAs. In this paper, weighted spectral clustering methods have been used to define the optimal layout of districts in a real water distribution system, taking into account both geometric and hydraulic features, through weighted adjacency matrices. The obtained results confirm the feasibility of the use of spectral clustering to address the arduous problem of water supply network partitioning with an elegant mathematical approach compared to other heuristic procedures proposed in the literature. A comparison between different spectral clustering solutions has been carried out through topological and energy performance indices, in order to identify the optimal water network partitioning procedure.

Performance of partitioned water distribution networks under spatial-temporal variability of water demand

Abstract Water network partitioning (WNP) into District Meter Areas allows improving pressure management, water budget, leaks detection, compared to classical redundantly looped networks. Anyway, WNP can significantly worsen the hydraulic performance, because often many gate valves are required, and the reduced set of possible paths for water flow makes the network vulnerable, especially to concentrated peaks of water request. Hence, reliably modeling the spatial and temporal distribution of water demand would allow better understanding the effects of WNP, improving both network design and management. Aiming at taking into account the behavior of a partitioned network under spatial and temporal variability of water demand, a design procedure is proposed, coupling a stochastic model of water demand with novel partitioning techniques, based on spectral clustering. The application of the procedure to a real medium-sized network shows that demand variability may significantly affect the hydraulic performance of the partitioned network, evaluated by means of topological and hydraulic indices.

DMA Optimal Layout for Protection of Water Distribution Networks from Malicious Attack

Water distribution networks (WDNs) are among the most important civil networks, because they deliver drinking and industrial water to metropolitan areas, supporting economic prosperity and quality of life. Therefore, they constitute critical infrastructures (CIs) as systems whose operability are of crucial importance to ensure social survival and welfare. In the last years, extreme natural events and intentional malicious attacks have shown that global safeguard of systems cannot be ever performed. In this regard, critical infrastructure protection (CIP) strategies should be focused both on the prevention of these events and on the procedures for the functioning recovery and damage limitation. In this paper, starting from previous works of the authors, the impact of an intentional contamination attack to water distribution network and a possible strategy to mitigate the user risk have been studied, simulating the introduction of potassium cyanide with a backflow attack into water system. As protection technique, the water network partitioning (WNP) has been adopted in order to improve the management and also to reduce the extent of damage showing a dual use-value. WNP reveals to be an efficient way to protect water networks from malicious contamination, through the closure of gate valves by a remote control system creating semi-independent District Meter Areas (DMAs). The study also investigates the possibility to identify a priori the most critical point of a water distribution network for the malicious attack through a novel procedure based on topological metric. The methodology, tested on a real medium size water network in Italy, shows very interesting results in terms of mitigation risk.

Water Distribution Network Clustering: Graph Partitioning or Spectral Algorithms?

Water Network Partitioning (WNP) is among the most attractive and studied strategies for the improvement of the Water Distribution Network (WDN) management. The proper definition of sub-regions (called clusters or districts) with high link density between nodes in the same group, and a relatively low link density between nodes in different groups, is a crucial aspect for the partitioning of a water system. If on one hand the definition of these monitored sub-areas, called District Metered Areas (DMAs), allows simplifying the water balance, the pressure control, the water leaks identification and the water quality protection, on the other hand it may worsen the hydraulic performance and the reliability of the system. In this paper, two clustering algorithms, graph partitioning based on a Multi-Level Recursive Bisection and Spectral Clustering, were used to define the districts. Some of the major geometrical and hydraulic characteristics of the network has been adopted as weights in the partitioning procedure. A comparison between the two clustering methods was made for a real water network of the South Italy, Parete, evaluating some clustering quality and hydraulic indices, in order to define the algorithm and the weight which work better for the definition of the optimal clustering layout.