scholarly journals Neural Network Approximation of Graph Fourier Transform for Sparse Sampling of Networked Dynamics

2022 ◽  
Vol 22 (1) ◽  
pp. 1-18
Author(s):  
Alessio Pagani ◽  
Zhuangkun Wei ◽  
Ricardo Silva ◽  
Weisi Guo
Keyword(s):  
Fourier Transform ◽  
Water Distribution ◽  
Distribution Networks ◽  
Sensor Data ◽  
Data Sampling ◽  
Sampling Schemes ◽  
Performance Guarantees ◽  
Wide Range ◽  
Contaminant Sources ◽  
Under Sampling

Infrastructure monitoring is critical for safe operations and sustainability. Like many networked systems, water distribution networks (WDNs) exhibit both graph topological structure and complex embedded flow dynamics. The resulting networked cascade dynamics are difficult to predict without extensive sensor data. However, ubiquitous sensor monitoring in underground situations is expensive, and a key challenge is to infer the contaminant dynamics from partial sparse monitoring data. Existing approaches use multi-objective optimization to find the minimum set of essential monitoring points but lack performance guarantees and a theoretical framework. Here, we first develop a novel Graph Fourier Transform (GFT) operator to compress networked contamination dynamics to identify the essential principal data collection points with inference performance guarantees. As such, the GFT approach provides the theoretical sampling bound. We then achieve under-sampling performance by building auto-encoder (AE) neural networks (NN) to generalize the GFT sampling process and under-sample further from the initial sampling set, allowing a very small set of data points to largely reconstruct the contamination dynamics over real and artificial WDNs. Various sources of the contamination are tested, and we obtain high accuracy reconstruction using around 5%–10% of the network nodes for known contaminant sources, and 50%–75% for unknown source cases, which although larger than that of the schemes for contaminant detection and source identifications, is smaller than the current sampling schemes for contaminant data recovery. This general approach of compression and under-sampled recovery via NN can be applied to a wide range of networked infrastructures to enable efficient data sampling for digital twins.

scholarly journals Complex network and fractal theory for the assessment of water distribution network resilience to pipe failures

2017 ◽  
Vol 18 (3) ◽  
pp. 767-777 ◽  
Author(s):  
Armando Di Nardo ◽  
Michele Di Natale ◽  
Carlo Giudicianni ◽  
Roberto Greco ◽  
Giovanni Francesco Santonastaso
Keyword(s):  
Complex Network ◽  
Water Distribution ◽  
Fractal Theory ◽  
Distribution Networks ◽  
Pipe Failure ◽  
Operational Conditions ◽  
Complex Network Theory ◽  
Topological Features ◽  
Wide Range ◽  
The Impact

AbstractWater distribution networks (WDNs) must keep a proper level of service under a wide range of operational conditions, and, in particular, the analysis of their resilience to pipe failures is essential to improve their design and management. WDNs can be regarded as large sparse planar graphs showing fractal and complex network properties. In this paper, the relationship linking the geometrical and topological features of a WDN to its resilience to the failure of a pipe is investigated. Some innovative indices have been borrowed from fractal geometry and complex network theory to study WDNs. Considering all possible network configurations obtained by suppressing one link, the proposed indices are used to quantify the impact of pipe failure on the system's resilience. This approach aims to identify critical links, in terms of resilience, with the help of topological metrics only, and without recourse to hydraulic simulations, which require complex calibration processes and come with a computational burden. It is concluded that the proposed procedure, which has been successfully tested on two real WDNs located in southern Italy, can provide valuable information to water utilities about which pipes have a significant role in network performance, thus helping in their design, planning and management.

scholarly journals A Six Sigma Approach to Water Savings

2017 ◽  
Vol 6 (2) ◽  
pp. 98
Author(s):  
Ryland Cairns ◽  
Michael Macpherson
Keyword(s):  
Six Sigma ◽  
Distribution System ◽  
Water Distribution ◽  
Demand Management ◽  
Distribution Networks ◽  
Water Losses ◽  
Water Savings ◽  
Wide Range ◽  
Six Sigma Approach

The purpose of this paper is to explore the potential of a six sigma approach to reducing water losses through a combination of water efficiency and leak detection on a private distribution system. The paper takes the form of a case study that investigates the implementation of water reduction strategy across an estate with 26 miles of potable water pipe and over 200 facilities. This incorporates methods developed in the water industry such as water loss reduction and water demand management. The paper demonstrates that large water savings could be made through adoption of a six sigma approach. The approach has the potential to be applied to a wide range of situations including sites with limited technology. This case study provides a useful source for Facilities Managers involved in the management of utilities to determine suitable water saving approaches and strategies for large estates with private water distribution networks.

The four Rs performance indicators of water distribution networks

2017 ◽  
Vol 34 (5) ◽  
pp. 720-732 ◽  
Author(s):  
Indra Gunawan ◽  
Frank Schultmann ◽  
Seyed Ashkan Zarghami
Keyword(s):  
Performance Indicators ◽  
System Performance ◽  
Distribution Systems ◽  
Water Distribution ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Critical Infrastructures ◽  
Content Type ◽  
Wide Range ◽  
Definition Of

Purpose The purpose of this paper is to review the different interpretations of four key performance indicators of water distribution networks (WDNs): reliability, resilience, redundancy and robustness. It then addresses a range of metrics which have been developed to assess the performance of critical infrastructures, in particular WDNs. Design/methodology/approach The paper provides a comprehensive review and categorization of performance indicators of WDNs. The main focus is on papers addressing performance indicators of water distribution systems, additionally papers on application of complex system approach to critical infrastructures are also included. Findings Due to this complexity, a wide range of interpretation of WDNs performance indicators exists in the literature. This represents a significant impediment toward universally accepted interpretation of these indicators Accurate assessment of WDNs’ performance depends on clear definition of system performance indicators as well as accurate quantifying of these indicators. The application of 18 metrics as a basis for assessing the system performance have been reviewed in this paper and none are particularly significant as standalone values. Combination of these indicators are required to accurately indicate the performance of WDNs. Originality/value The authors believe that this paper can be a valuable source of information for academic researchers and practitioners and suggests a roadmap for future works.

scholarly journals The Application of K Value Adaptive VMD Method in Pipeline Leakage Location

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
R. F. Liu ◽  
M. J. Yang ◽  
C. Q. Sun ◽  
S. Zeng
Keyword(s):  
Water Distribution ◽  
Saddle Points ◽  
Distribution Networks ◽  
Time Delay Estimation ◽  
Signal Frequency ◽  
Intrinsic Mode Functions ◽  
K Value ◽  
Wide Range ◽  
Sampled Signal ◽  
Leakage Location

The research about online monitoring and leakage automatic location of water distribution networks (WDN) has a wide range of applications that include water resource protection, monitoring, and allocation. Variational mode decomposition (VMD) and cross-correlation (CC) based leakage location is a popular and effective method in WDN. However, the value of K intrinsic mode functions (IMFs) based on VMD decomposition needs to be determined artificially, which affects the separation effect of signal frequency band characteristics directly. Hence, this work proposes an adaptive method to determine the parameter K of leakage vibration signal’s IMFs, which will be applied to automatic leakage location in WDN. Firstly, the number of saddle points in the frequency domain envelope of the sampled signal in different step sizes is calculated. The parameter K is determined according to the curvature change of the number of saddle points and the sampled signal. Finally, the selective IMFs are reconstituted into a new signal, which can determine a leak position using CC based time-delay estimation (TDE). To verify the effectiveness of the proposed algorithm, the different methods based on EMD and Fast ICA are compared. The experimental results demonstrate that the proposed parameter K value adaptive VMD (KVA-VMD) decomposition method is more suitable for leakage location in WDN.

scholarly journals A systematic mixed-integer differential evolution approach for water network operational optimization

2018 ◽  
Vol 474 (2217) ◽  
pp. 20170879 ◽  
Author(s):  
Wanqing Zhao ◽  
Thomas H. Beach ◽  
Yacine Rezgui
Keyword(s):  
Differential Evolution ◽  
Value Chain ◽  
Water Distribution ◽  
Cost Savings ◽  
Distribution Networks ◽  
Mixed Integer ◽  
Water Network ◽  
Operational Strategy ◽  
Time Operation ◽  
Wide Range

The operational management of potable water distribution networks presents a great challenge to water utilities, as reflected by the complex interplay of a wide range of multidimensional and nonlinear factors across the water value chain including the network physical structure and characteristics, operational requirements, water consumption profiles and the structure of energy tariffs. Nevertheless, both continuous and discrete actuation variables can be involved in governing the water network, which makes optimizing such networks a mixed-integer and highly constrained decision-making problem. As such, there is a need to situate the problem holistically, factoring in multidimensional considerations, with a goal of minimizing water operational costs. This paper, therefore, proposes a systematic optimization methodology for (near) real-time operation of water networks, where the operational strategy can be dynamically updated using a model-based predictive control scheme with little human intervention. The hydraulic model of the network of interest is thereby integrated and successively simulated with different trial strategies as part of the optimization process. A novel adapted mixed-integer differential evolution (DE) algorithm is particularly designed to deal with the discrete-continuous actuation variables involved in the network. Simulation results on a pilot water network confirm the effectiveness of the proposed methodology and the superiority of the proposed mixed-integer DE in comparison with genetic algorithms. It also suggests that 23.69% cost savings can be achieved compared with the water utility's current operational strategy, if adaptive pricing is adopted for all the pumping stations.

scholarly journals Prior Assumptions for Leak Localisation in Water Distribution Networks with Uncertainties

2021 ◽  
Author(s):  
Caroline Blocher ◽  
Filippo Pecci ◽  
Ivan Stoianov
Keyword(s):  
Water Distribution ◽  
Network Models ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Sensitivity Matrix ◽  
Leak Location ◽  
Wide Range ◽  
Coefficient Vector ◽  
Resistance Coefficients ◽  
Location Estimate

AbstractHydraulic model-based leak (burst) localisation in water distribution networks is a challenging problem due to a limited number of hydraulic measurements, a wide range of leak properties, and model and data uncertainties. In this study, prior assumptions are investigated to improve the leak localisation in the presence of uncertainties. For example, $$\ell _2$$ ℓ 2 -regularisation relies on the assumption that the Euclidean norm of the leak coefficient vector should be minimised. This approach is compared with a method based on the sensitivity matrix, which assumes the existence of only a single leak. The results show that while the sensitivity matrix method often yields a better leak location estimate in single leak scenarios, the $$\ell _2$$ ℓ 2 -regularisation successfully identifies a search area for pinpointing the accurate leak location. Furthermore, it is shown that the additional error introduced by a quadratic approximation of the Hazen-Williams formula for the solution of the localisation problem is negligible given the uncertainties in Hazen-Williams resistance coefficients in operational water network models.

scholarly journals Interactions of Cryptosporidium parvum, Giardia lamblia, Vaccinal Poliovirus Type 1, and Bacteriophages φX174 and MS2 with a Drinking Water Biofilm and a Wastewater Biofilm

2008 ◽  
Vol 74 (7) ◽  
pp. 2079-2088 ◽  
Author(s):  
Karim Helmi ◽  
Sylvain Skraber ◽  
Christophe Gantzer ◽  
Raphaël Willame ◽  
Lucien Hoffmann ◽  
...  
Keyword(s):  
Drinking Water ◽  
Cryptosporidium Parvum ◽  
Giardia Lamblia ◽  
Viral Genome ◽  
Water Distribution ◽  
Distribution Networks ◽  
Protozoan Parasites ◽  
Poliovirus Type ◽  
Wide Range

ABSTRACT Biofilms colonizing surfaces inside drinking water distribution networks may provide a habitat and shelter to pathogenic viruses and parasites. If released from biofilms, these pathogens may disseminate in the water distribution system and cause waterborne diseases. Our study aimed to investigate the interactions of protozoan parasites (Cryptosporidium parvum and Giardia lamblia [oo]cysts) and viruses (vaccinal poliovirus type 1, φX174, and MS2) with two contrasting biofilms. First, attachment, persistence, and detachment of the protozoan parasites and the viruses were assessed with a drinking water biofilm. This biofilm was allowed to develop inside a rotating annular reactor fed with tap water for 7 months prior to the inoculation. Our results show that viable parasites and infectious viruses attached to the drinking water biofilm within 1 h and persisted within the biofilm. Indeed, infectious viruses were detected in the drinking water biofilm up to 6 days after the inoculation, while viral genome and viable parasites were still detected at day 34, corresponding to the last day of the monitoring period. Since viral genome was detected much longer than infectious particles, our results raise the question of the significance of detecting viral genomes in biofilms. A transfer of viable parasites and viruses from the biofilm to the water phase was observed after the flow velocity was increased but also with a constant laminar flow rate. Similar results regarding parasite and virus attachment and detachment were obtained using a treated wastewater biofilm, suggesting that our observations might be extrapolated to a wide range of environmental biofilms and confirming that biofilms can be considered a potential secondary source of contamination.

scholarly journals Optimal Sensor Placement in Hydraulic Conduit Networks: A State-Space Approach

Water ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3105
Author(s):  
Caspar V. C. Geelen ◽  
Doekle R. Yntema ◽  
Jaap Molenaar ◽  
Karel J. Keesman
Keyword(s):  
State Space ◽  
Water Distribution ◽  
Fluid Transport ◽  
Model Simulation ◽  
Sensor Placement ◽  
Distribution Networks ◽  
Sensor Data ◽  
Optimal Sensor Placement ◽  
Time Flow ◽  
Conduit Networks

Conduit bursts or leakages present an ongoing problem for hydraulic fluid transport grids, such as oil or water conduit networks. Better monitoring allows for easier identification of burst sites and faster response strategies but heavily relies on sufficient insight in the network’s dynamics, obtained from real-time flow and pressure sensor data. This paper presents a linearized state-space model of hydraulic networks suited for optimal sensor placement. Observability Gramians are used to identify the optimal sensor configuration by maximizing the output energy of network states. This approach does not rely on model simulation of hydraulic burst scenarios or on burst sensitivity matrices, but, instead, it determines optimal sensor placement solely from the model structure, taking into account the pressure dynamics and hydraulics of the network. For a good understanding of the method, it is illustrated by two small water distribution networks. The results show that the best sensor locations for these networks can be accurately determined and explained. A third example is added to demonstrate our method to a more realistic case.

scholarly journals Evaluation of performance and environmental benefits of a full-scale pump as turbine system in Antalya water distribution network

2017 ◽  
Vol 18 (1) ◽  
pp. 130-141 ◽  
Author(s):  
Ayse Muhammetoglu ◽  
Cezmi Nursen ◽  
I. Ethem Karadirek ◽  
Habib Muhammetoglu
Keyword(s):  
Carbon Dioxide Emissions ◽  
Energy Production ◽  
Water Distribution ◽  
Distribution Networks ◽  
Green Energy ◽  
Full Scale ◽  
Environmental Benefits ◽  
Evaluation Of Performance ◽  
Wide Range ◽  
Pat System

Abstract In recent years, pumps used in turbine mode (pump as turbine, PAT) have started to appear as a viable option to reduce pressure in water distribution networks in addition to energy production at micro scale. In this study, evaluation of performance of a recently installed PAT system in Antalya City, Turkey, is presented for the first operational period of approximately 5 months. This full-scale PAT system was implemented in a parallel pipeline with a pressure reducing valve. The operation of the installed PAT system was continuously monitored online for flow rate, power and pressure. The installed PAT system, being in operation since 26 January 2016, works efficiently in a wide range of inflows (130–300 m3/h) and the produced energy varies between 0.7 and 8.4 kWh for a reduction of approximately one bar pressure head with an average efficiency of 60%. Based on the initial 5 months of operational data, environmental benefits of green energy production, reduction in physical water losses and carbon dioxide emissions were evaluated. Based on the implementation cost of the PAT system and the revenues from the environmental benefits, payback period of this specific full-scale PAT application was computed as 53 days or 1.8 months.

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