SMaRT-OnlineWDN: A Franco-German Project For The Online Security Management Of Water Distribution Networks

Water Distribution Networks (WDNs) are critical infrastructures that are exposed to deliberate or accidental chemical, biological or radioactive contamination which need to be detected in due time. However, until now, no monitoring system is capable of protecting a WDN in real time. Powerful online sensor systems are currently developed and the prototypes are able to detect a small change in water quality. In the immediate future, water service utilities will install their networks with water quantity and water quality sensors. For taking appropriate decisions and countermeasures, WDN operators will need to dispose of: 1) a fast and reliable detection of abnormal events in the WDNs; 2) reliable online models both for the hydraulics and water quality predictions; 3) methods for contaminant source identification backtracking from the data history. Actually, in general none of these issues (1) – (3) are available at the water suppliers. Consequently, the main objective of the project SMaRT-OnlineWDN is the development of an online security management toolkit for WDNs that is based on sensor measurements of water quality as well as water quantity. Its main innovations are the detection of abnormal events with a binary classifier of high accuracy and the generation of real-time, reliable (i) flow and pressure predictions, (ii) water quality indicator predictions of the whole water network. Detailed information regarding contamination sources (localization and intensity) will be explored by means of the online running model, which is automatically calibrated to the measured sensor data. Its field of application ranges from the detection of deliberate contamination including source identification and decision support for effective countermeasures to improved operation and control of a WDN under normal and abnormal conditions (dual benefit).In this project, the technical research work is completed with a sociological, economical and management analysis

Lessons Learned In Solving The Contaminant Source Identification In An Online Context

Protection of Water Distribution Networks (WDNs) against contamination events has a paramount importance. Either deliberate or accidental contamination of these infrastructures has strong negative consequences from both social and economical point of view. The project SMaRT-OnlineWDN aimed to develop methods and software solutions 1) to detect contamination from non-specific sensors, 2) to maintain an online water quantity and water quality model that is reliable and 3) to use the past model predictions to backtrack the potential sources of contaminations. For source identification, is more reliable velocities from an historical data base a substantial advantage compared to offline velocity predictions? The aim of this paper is to answer to this question and to report the main findings in the SMaRT-OnlineWDN project for contaminant source identification in an online context. The problem of source identification consists in determining the location and duration of a contamination taking into account sensor responses. Our solution is a two-step enumeration/exploration method. Firstly, we solve the transport equation in reverse time for enumeration of the potential solutions. This is made independent of the reaction kinetics of particular substances. The known boundary conditions are the responses of sensors that count the successive contaminant fronts arriving at each sensor. In the second exploration step a probability calculation for ranking of the candidate solutions is proposed with two general stochastic methods (minimum relative entropy or least squares methods). An extensive use of simplification methods is carried on both temporally and spatially on the dynamic graph. A sensitivity analysis is made with regards to the demand uncertainty. Results on real networks in France and Germany are presented

Oligocene and early Miocene mammal biostratigraphy of the Valley of Lakes in Mongolia

The Taatsiin Gol Basin in Mongolia is a key area for understanding the evolution and dispersal of Central Asian mammal faunas during the Oligocene and early Miocene. After two decades of intense fieldwork, the area is extraordinarily well sampled and taxonomically well studied, yielding a large dataset of 19,042 specimens from 60 samples. The specimens represent 176 species-level and 99 genus-level taxa comprising 135 small mammal species and 47 large mammals. A detailed lithostratigraphy and new magnetostratigraphic and radiometric datings provide an excellent frame for these biotic data. Therefore, we test and evaluate the informal biozonation scheme that has been traditionally used for biostratigraphic correlations within the basin. Based on the analysis of the huge dataset, a formalised biostratigraphic scheme is proposed. It comprises the Cricetops dormitor Taxon Range Zone (Rupelian), subdivided into the Allosminthus khandae Taxon Range Subzone and the Huangomys frequens Abundance Subzone, the Amphechinus taatsiingolensis Abundance Zone (early Chattian), the Amphechinus major Taxon Range Zone (late Chattian), subdivided into the Yindirtemys deflexus Abundance Subzone and the Upper Amphechinus major T. R. Z., and the Tachyoryctoides kokonorensis Taxon Range Zone (Aquitanian). In statistical analyses, samples attributed to these biozones form distinct clusters, indicating that each biozone was also characterised by a distinct faunal type

Adaptive Modeling Of Water Supply Networks For Improved Practical Applicability Of Hydraulic Online-Simulation

Online-Simulation of water distribution networks allows for estimating the current state of the entire network in near real-time. Measurement data coming from sensors at selected positions in the real network are used for driving a mathematical simulation model. Therefore the information gained from the measurements is extended and covers the whole system. As part of online monitoring or decision support systems online-simulations have multiple applications in operations and control of water supply networks. Although sensors and techniques for data transfer as well as mathematical simulation techniques are highly developed the practical applicability of online-simulations for decision support in large networks still suffers from the high time requirements for the whole cycle of measurement data updates, simulation and post-processing. One common approach to tackle this problem is the aggregation of the underlying models. However, for some applications like contaminant source identification the information that is lost can be crucial for the reliability of the decisions that are made based on the online-simulation results. In order to enhance online calculations and to improve the practical applicability of large online simulation models an adaptive calculation framework has been developed that allows for running the model with different levels of accuracy but using all one and the same data base. For each problem an adequate level of accuracy is chosen. Higher functions like source identification or optimisation algorithms that require a number of extra simulations can be focused on selected regions of the network. For the subnetwork in question detailed data are used whereas the rest of the system is omitted or, if necessary, considered with a lower level of accuracy. The framework is based on topological analysis and decomposition of the network graph. The paper describes the basic concepts and demonstrates its applicability by means of contaminant source identification

A Gradient-Type Method For Real-Time State Estimation Of Water Distribution Networks

Drinking water distribution networks risk exposure to malicious or accidental contamination. Several levels of responses are conceivable. One of them consists to install a sensor network to monitor the system on real time. Once a contamination has been detected, this is also important to take appropriate counter-measures. In the SMaRT-OnlineWDN project, this relies on modeling to predict both hydraulics and water quality. An online model use makes identification of the contaminant source and simulation of the contaminated area possible. The objective of this paper is to present SMaRT-OnlineWDN experience and research results for hydraulic state estimation with sampling frequency of few minutes. A least squares problem with bound constraints is formulated to adjust demand class coefficient to best fit the observed values at a given time. The criterion is a Huber function to limit the influence of outliers. A Tikhonov regularization is introduced for consideration of prior information on the parameter vector. Then the Levenberg-Marquardt algorithm is applied that use derivative information for limiting the number of iterations. Confidence intervals for the state prediction are also given. The results are presented and discussed on real networks in France and Germany

Battle of Postdisaster Response and Restoration

[EN] The paper presents the results of the Battle of Postdisaster Response and Restoration (BPDRR) presented in a special session at the first International water distribution systems analysis & computing and control in the water industry (WDSA/CCWI) Joint Conference, held in Kingston, Ontario, Canada, in July 2018. The BPDRR problem focused on how to respond and restore water service after the occurrence of five earthquake scenarios that cause structural damage in a water distribution system. Participants were required to propose a prioritization schedule to fix the damages of each scenario while following restrictions on visibility/nonvisibility of damages. Each team/approach was evaluated against six performance criteria: (1) time without supply for hospital/firefighting, (2) rapidity of recovery, (3) resilience loss, (4) average time of no user service, (5) number of users without service for eight consecutive hours, and (6) water loss. Three main types of approaches were identified from the submissions: (1) general-purpose metaheuristic algorithms, (2) greedy algorithms, and (3) ranking-based prioritizations. All three approaches showed potential to solve the challenge efficiently. The results of the participants showed that for this network, the impact of a large-diameter pipe failure on the network is more significant than several smaller pipes failures. The location of isolation valves and the size of hydraulic segments influenced the resilience of the system during emergencies. On average, the interruptions to water supply (hospitals and firefighting) varied considerably among solutions and emergency scenarios, highlighting the importance of private water storage for emergencies. 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Kingston Canada: Open Journal Systems

Modélisation et optimisation des réseaux de conduites sous pression

Drinking water distribution systems are critical, complex and interconnected infrastructures, of vital importance for human live and welfare. They may suffer physical damage or an important malfunctioning in case of a natural or anthropic disaster. Also, these systems are ageing, which emphasizes the water quality deterioration at the consumer taps and the water losses. This report describes twenty years of research work in Applied Mathematics and Engineering Sciences aiming to provide affordable solutions in terms of quality of service, security and sustainability. In the first part, a convex optimization problem is used to effectively address the large-size network solving issue. Then, local sensitivity of steady state solutions to variations in parameters are made explicit. Following, the primal formulation is generalized for encompassing leakage outflows, high-lying points and inertia terms. Finally, it is shown object-oriented programming and parallelisation effort may provide improved performance for solving large systems. In the second part, three important associated inverse problems are solved to consider control valves in modeling, or calibrate the model input parameters or still seeking optimal sensor placement. Solving algorithms are based on first- order information. The third part is devoted to water quality indicator transport and reaction modeling. Two algorithms are described, which are specially adapted to each physical phenomenon and to the hydraulic predictions, which are weakly coupled. Then, they are compared to classical algorithms. Next, sensitivity equations are made explicit. They share the same structure as the direct problem with an additional source term. Finally, the main results are reminded, as well as perspectives of research are given.Les réseaux d'alimentation en eau potable sont des infrastructures complexes et interconnectées, d'importance vitale, essentielles pour le bien-être de l'homme et de l'humanité. Ils peuvent subir des dommages physiques ou un dysfonctionnement important suite à une catastrophe naturelle ou anthropique. Aussi, le vieillissement de ces systèmes de distribution accentue les causes de détérioration de la qualité de l'eau au robinet du consommateur et le gaspillage de la ressource. Ce mémoire décrit vingt ans de recherche en mathématiques appliquées et en sciences pour l'ingénieur pour apporter des solutions abordables en termes de qualité de service, de sécurité et de durabilité. Dans une première partie, la formulation d'un problème d'optimisation convexe est utilisée pour résoudre efficacement les équations d'équilibrage hydraulique pour des réseaux de grandes tailles. Puis, les sensibilités locales de la solution aux variations des paramètres sont explicitées. Ensuite, la formulation primale est étendue pour permettre l'incorporation de fuites, la prise en compte de points hauts et de termes d'inertie. Enfin, les apports du génie logiciel sont examinés, à la fois en programmation orientée objet et en parallélisation, vis-à-vis de la performance du calcul. Dans la seconde partie, quelques problèmes inverses importants sont alors traités, pour prendre en compte les vannes de contrôle, ou bien caler les paramètres du modèle ou encore optimiser l'emplacement de points de mesure. Les algorithmes de résolutions utilisent de façon centrale les informations du premier ordre. La troisième partie est consacrée à la modélisation du transport et de la réaction d'indicateurs de la qualité de l'eau. Deux algorithmes sont décrits, lesquels sont spécialement adaptés aux phénomènes physiques et au modèle hydraulique faiblement couplé. Ils sont ensuite comparés aux algorithmes les plus classiques. Ensuite, les équations de sensibilités sont explicitées. Elles possèdent une même structure que le problème direct avec en plus un terme source additionnel. Finalement, les principaux résultats sont rappelés ainsi que des perspectives de recherche sont données

Modélisation du fonctionnement d'un réseau. Analyse hydraulique et choix des mesures pour l'estimation de paramètres

The objective of this thesis is the modelling of the operation of water supply network in permanent state by adopting a good measurement strategy. It includes three sections: the solving of water balancing equations, that of the network identification problem and that of the choice of measurements.Le but de cette thèse est de réaliser la modélisation du fonctionnement d'un réseau d'alimentation en eau potable, en régime permanent, en adoptant une bonne stratégie de mesure. Elle comprend trois parties : la résolution des équations d'équilibrage hydraulique, celle du problème de l'identification du réseau et celle du choix des mesures