Scientific Results

This catalogue is obtained by conducting a systematic literature review of scientific studies and reviews related to monitoring, forecasting, and simulating the inland water cycle. The analysis maps scientific expertise across research groups and classifies findings by the type of inland water studied, application focus, and geographical scope. A gap analysis will identify missing research areas and assess their relevance to policymaking.

ID ▲	Type	Year	Authors	Title	Venue/Journal	DOI	Abstract
publications-3741	article	1998	Watts, Duncan J. and Watts, Duncan J. and Strogatz, Steven H. and Strogatz, Steven H.	Collective dynamics of small-world networks	Nature	10.1038/30918	Networks of coupled dynamical systems have been used to model biological oscillators1,2,3,4, Josephson junction arrays5,6, excitable media7, neural networks8,9,10, spatial games11, genetic control networks12 and many other self-organizing systems. Ordinarily, the connection topology is assumed to be either completely regular or completely random. But many biological, technological and social networks lie somewhere between these two extremes. Here we explore simple models of networks that can be tuned through this middle ground: regular networks β€rewiredβ€™ to introduce increasing amounts of disorder. We find that these systems can be highly clustered, like regular lattices, yet have small characteristic path lengths, like random graphs. We call them β€small-worldβ€™ networks, by analogy with the small-world phenomenon13,14 (popularly known as six degrees of separation15). The neural network of the worm Caenorhabditis elegans, the power grid of the western United States, and the collaboration graph of film actors are shown to be small-world networks. Models of dynamical systems with small-world coupling display enhanced signal-propagation speed, computational power, and synchronizability. In particular, infectious diseases spread more easily in small-world networks than in regular lattices.
publications-3742	article	2007	Brumbelow, Kelly and Brumbelow, Kelly and Torres, Jacob M. and Torres, Jacob M. and Guikema, Seth D. and Guikema, Seth D. and Bristow, Elizabeth and Bristow, Elizabeth and Kanta, Lufthansa and Kanta, Lufthansa	Virtual cities for water distribution and infrastructure system research		10.1061/40927(243)469	In a society concerned over the possibility of terrorism, secrecy , and security of infrastructure data is crucial. However, research on infrastructure security is difficult in this environment since experiments on real systems can not be publicized. β€_x009c_Virtual citiesβ€_x009d_ are one potential answer to this problem, and a library of these virtual cities is now under development. β€_x009c_Micropolisβ€_x009d_ is a virtual city of 5000 resi dents fully described in both GIS and EPANet hydraulic model frameworks. To simulate realism of infrastructure, a developmental timeline spanning 130 years was included. This timeline is manifested in items such as pipe material, diameter, and topology. An example of using the virtual city for simulation of fire protection is presented. The data files describing Micropolis are avail able from the authors for other sβ€™ use. A larger city, β€_x009c_Mesopolis,β€_x009d_ is currently under development and will incorporate add itional critical infrastructure dependencies such as electrical power grids and communications. This will supplement the development of further models to account for risks and probability of electrical power failure due to hurricane events. It is hoped t hat Micropolis, Mesopolis , and additional virtual cities will serve as a β€_x009c_hubβ€_x009d_ for the development of further research models.
publications-3743	article	2004	Ostfeld, Avi and Salomons, Elad	Optimal Layout of Early Warning Detection Stations for Water Distribution Systems Security	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(2004)130:5(377)	Deliberate contamination is generally viewed as the most serious potential terrorist threat to water systems. Chemical or biological agents could spread throughout a distribution system and result in sickness or death among the people drinking the water. Since September 11, 2001 the U.S. Environmental Protection Agency's water protection task force and regional offices have initiated massive actions to improve the security of the drinking water infrastructure. A methodology is presented for finding the optimal layout of an early warning detection system ~EWDS!. The detection system is comprised of a set of monitoring stations aimed at capturing deliberate external terrorist hazard intrusions through water distribution system nodesβ€”sources, tanks, and consumers. The optimization considers extended period unsteady hydraulics and water quality conditions for a given defensive level of service to the public, defined as a maximum volume of polluted water exposure at a concentration higher than a minimum hazard level. Such a scheme provides an EWDS for a deliberate terrorist external hazard intrusion, as well as for accidental contamination entries under unsteady conditionsβ€”a problem that currently has not been solved. The methodology is cast in a genetic algorithm framework for integration with EPANET and is demonstrated through two example applications. DOI: 10.1061/~ASCE!0733-9496~2004!130:5~377! CE Database subject headings: Water distribution; Monitoring; Optimization; Evolutionary computation; Water quality; Security; Terrorism.
publications-3744	article	2011	Perelman, Lina and Ostfeld, Avi	Short communication: Topological clustering for water distribution systems analysis	Environmental Modelling and Software	10.1016/j.envsoft.2011.01.006
publications-3745	article	2008	Ostfeld, Avi and Uber, James G. and Salomons, Elad and Berry, Jonathan W. and Hart, William E. and Phillips, Cynthia A. and Watson, Jean-Paul and Dorini, G. and Jonkergouw, Philip and Kapelan, Zoran and di Pierro, Francesco and Khu, Soon-Thiam and Savic, Dragan and Eliades, Demetrios G. and Polycarpou, Marios M. and Ghimire, Santosh R. and Barkdoll, Brian D. and Gueli, Roberto and Huang, Jinhui J. and Huang, Jinhui Jeanne and McBean, Edward A. and James, William and Krause, Andreas and Leskovec, Jure and Isovitsch, Shannon L. and Xu, Jianhua and Guestrin, Carlos and VanBriesen, Jeanne M. and Small, Mitchell J. and Fischbeck, Paul S. and Preis, Ami and Propato, Marco and Piller, Olivier and Trachtman, Gary B. and Wu, Zheng Yi and Walski, Thomas M.	The battle of the water sensor networks (BWSN): A design challenge for engineers and algorithms	Journal of Water Resources Planning and Management	10.1061/(asce)0733-9496(2008)134:6(556)	Following the events of September 11, 2001, in the United States, world public awareness for possible terrorist attacks on water supply systems has increased dramatically. Among the different threats for a water distribution system, the most difficult to address is a deliberate chemical or biological contaminant injection, due to both the uncertainty of the type of injected contaminant and its consequences, and the uncertainty of the time and location of the injection. An online contaminant monitoring system is considered as a major opportunity to protect against the impacts of a deliberate contaminant intrusion. However, although optimization models and solution algorithms have been developed for locating sensors, little is known about how these design algorithms compare to the efforts of human designers, and thus, the advantages they propose for practical design of sensor networks. To explore these issues, the Battle of the Water Sensor Networks (BWSN) was undertaken as part of the 8th Annual Water Dist...
publications-3746	article	2014	Rasekh, Amin and Shafiee, M. Ehsan and Zechman, Emily M. and Brumbelow, Kelly	Sociotechnical risk assessment for water distribution system contamination threats	Journal of Hydroinformatics	10.2166/hydro.2013.023	Water distribution systems (WDS) are vulnerable to contaminants, and systematic risk assessment can provide valuable information for assisting threat management. Contamination events are sociotechnical systems, in which the interactions among consumers and water infrastructure may generate unpredicted public health consequences. This research develops a sociotechnical risk assessment framework that simulates the dynamics of a contamination event by coupling an agent-based modeling (ABM) framework with Monte Carlo simulation (MCS), genetic algorithm (GA) optimization, and a multi-objective GA. The ABM framework couples WDS simulation with agents to represent consumers in a virtual city. MCS is applied to estimate the uncertainty in human exposure, based on probabilistic models of event attributes. A GA approach is used to identify critical contamination events by maximizing risk, and a multi-objective approach explores the trade-off between consequence and occurrence probabilities. Results that are obtained using the sociotechnical approach are compared with results obtained using a conventional engineering model. The sociotechnical approach removes assumptions that have been used in engineering analysis about the static, homogeneous, and stationary behaviors of consumers, and results demonstrate new insight about the impacts of these actions and interactions on the public health consequences of contamination events.
publications-3747	article	2016	Koutiva, Ifigeneia and Koutiva, Ifigeneia and Makropoulos, Christos and Makropoulos, Christos	Modelling domestic water demand	Environmental Modelling and Software	10.1016/j.envsoft.2016.01.005
publications-3748	article	2017	Walski, Thomas M. and Walski, Thomas M.	Procedure for Hydraulic Model Calibration	Journal American Water Works Association	10.5942/jawwa.2017.109.0075	Calibrating a model can appear to be a daunting task, but by using an organized approach, the modeler can make the right adjustments and understand why.
publications-3749	article	2018	Abdulkareem, Shaheen A. and Abdulkareem, Shaheen A. and Augustijn, Ellen-Wien and Augustijn, Ellen-Wien and Mustafa, Yaseen T. and Mustafa, Yaseen T. and Filatova, Tatiana and Filatova, Tatiana	Intelligent judgements over health risks in a spatial agent-based model	International Journal of Health Geographics	10.1186/s12942-018-0128-x	Millions of people worldwide are exposed to deadly infectious diseases on a regular basis. Breaking news of the Zika outbreak for instance, made it to the main media titles internationally. Perceiving disease risks motivate people to adapt their behavior toward a safer and more protective lifestyle. Computational science is instrumental in exploring patterns of disease spread emerging from many individual decisions and interactions among agents and their environment by means of agent-based models. Yet, current disease models rarely consider simulating dynamics in risk perception and its impact on the adaptive protective behavior. Social sciences offer insights into individual risk perception and corresponding protective actions, while machine learningprovides algorithms and methods to capture these learning processes. This article presents an innovative approach to extend agent-based disease models by capturing behavioral aspects of decision-making in a risky context using machine learningtechniques. We illustrate it with a case of cholera in Kumasi, Ghana, accounting for spatial and social risk factors that affect intelligent behavior and corresponding disease incidents. The results of computational experiments comparing intelligent with zero-intelligent representations of agents in a spatial disease agent-based model are discussed. We present a spatial disease agent-based model (ABM) with agentsβ€™ behavior grounded in Protection Motivation Theory. Spatial and temporal patterns of disease diffusion among zero-intelligent agents are compared to those produced by a population of intelligent agents. Two Bayesian Networks (BNs) designed and coded using R and are further integrated with the NetLogo-based Cholera ABM. The first is a one-tier BN1 (only risk perception), the second is a two-tier BN2 (risk and coping behavior). We run three experiments (zero-intelligent agents, BN1 intelligence and BN2 intelligence) and report the results per experiment in terms of several macro metrics of interest: an epidemic curve, a risk perception curve, and a distribution of different types of coping strategies over time. Our results emphasize the importance of integrating behavioral aspects of decision making under risk into spatial disease ABMs using machine learning algorithms. This is especially relevant when studying cumulative impacts of behavioral changes and possible intervention strategies.
publications-3750	article	2019	Page, Philip R. and Page, Philip R. and Zulu, S'bonelo and Zulu, Sβ€™Bonelo and Mothetha, Matome L. and Mothetha, Matome L.	Remote real-time pressure control via a variable speed pump in a specific water distribution system	Journal of Water Supply Research and Technology-aqua	10.2166/aqua.2018.074	Pressure management (PM) in a water distribution system (WDS) can be accomplished by setting the pressure to be low and constant at remote consumer locations, through the use of a controller. The controller adjusts the speed of a variable speed pump (VSP) in real time. To study the implementation of these concepts, the installation of a VSP for PM in a real-world WDS in South Africa is investigated with a hydraulic model, to show how this can assist in addressing challenges and to determine the adequacy of various controllers. In this study, a suitable pump is installed which is sized to supply the required set pressure at maximum demand. Previously existing pressure deficiency challenges are solved. PM with recently proposed controllers, which depend on hydraulics theory, is performed for the first time for a WDS which exists in the real world. Since these controllers need to be studied under realistic conditions, stochastic water consumption is used. All controllers, including conventional proportional control, perform well. A consequence of this is that a controller without a tunable parameter can initially be used safely, and a related controller can then be tuned slowly to improve performance. Criteria for selecting an appropriate controller are given.