| publications-4121 |
article |
2004 |
Barreteau, Olivier and Barreteau, Olivier and Bousquet, François and Bousquet, François and Millier, Claude and Millier, Claude and Wéber, Jacques and Weber, Jacques |
Suitability of Multi-Agent Simulations to study irrigated system viability: application to case studies in the Senegal River Valley |
Agricultural Systems |
10.1016/j.agsy.2003.07.005 |
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| publications-4122 |
article |
2013 |
Wang, Hui and Wang, Hui and Wang, Hui and Harrison, Kenneth W. and Harrison, Kenneth W. |
Bayesian update method for contaminant source characterization in water distribution systems. |
Journal of Water Resources Planning and Management |
10.1061/(asce)wr.1943-5452.0000221 |
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AbstractBayesian analysis has application to probabilistic source characterization in water distribution systems. A new implementation of Markov-chain Monte Carlo (MCMC) for this problem is described. The solution addresses the discrete nature of water distribution networks that precludes the application of MCMC methods of general applicability that have been reported elsewhere in the water resources literature. The method is applied to a hypothetical network that has been used by others to test source identification methods. The likelihood function, a key component of Bayes’ rule, is evaluated using a Monte Carlo–based stochastic water-demand model. The results reinforce the need to address the multiple sources of uncertainty in the source characterization, including the stochastic variation of water demand. Further research is needed to make the approach feasible in operational environments. Limitations of the approach and future research directions are discussed. |
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| publications-4123 |
article |
2011 |
Langner, Ralph and Langner, R |
Stuxnet: Dissecting a Cyberwarfare Weapon |
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10.1109/msp.2011.67 |
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Last year marked a turning point in the history of cybersecurity-the arrival of the first cyber warfare weapon ever, known as Stuxnet. Not only was Stuxnet much more complex than any other piece of malware seen before, it also followed a completely new approach that's no longer aligned with conven tional confidentiality, integrity, and availability thinking. Con trary to initial belief, Stuxnet wasn't about industrial espionage: it didn't steal, manipulate, or erase information. Rather, Stuxnet's goal was to physically destroy a military target-not just meta phorically, but literally. Let's see how this was done. |
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| publications-4124 |
article |
1997 |
Kaplan, Stan and Kaplan, S. |
The Words of Risk Analysis |
Risk Analysis |
10.1111/j.1539-6924.1997.tb00881.x |
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This paper is a transcript of a talk given to a plenary session at the 1996 Annual Meeting of the Society for Risk Analysis. Its purpose is to contribute toward a single, uniformly understood language for the risk analysis community. |
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| publications-4125 |
article |
2004 |
McInnis, Duncan A. and McInnis, Duncan A. |
A relative-risk framework for evaluating transient pathogen intrusion in distribution systems |
Urban Water Journal |
10.1080/15730620412331290010 |
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Hydraulic transients generate significant negative pressures in water systems that may cause intrusion of contaminated water from the environment into the pipe. This paper expands the consideration of transient intrusion events from their purely hydraulic aspects by developing a risk-based framework for comparing the relative risk-reduction achieved by alternative transient-intrusion mitigation strategies. Alternative strategies may be any combination of changes to system operation or surge controls that would reduce the potential for intrusion of contaminants from the soil-groundwater environment surrounding the pipe. A reference groundwater contamination is assumed, and intrusion volumes and time-varying pathogen concentrations are computed respectively using hydraulic transient and water quality models. Risk-based measures are proposed to provide quantitative assessments of the relative reduction in the risk of receptor infection achieved by alternative mitigation strategies. |
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| publications-4126 |
article |
2006 |
Baranowski, T. M. and Baranowski, T. M. and LeBoeuf, Eugene J. and LeBoeuf, Eugene J. |
Consequence Management Optimization for Contaminant Detection and Isolation |
Journal of Water Resources Planning and Management |
10.1061/(asce)0733-9496(2006)132:4(274) |
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Vulnerability assessments may be used to help identify components of water distribution systems that require strengthening against possible attacks, including physical destruction and/or chemical contamination. Numerous recent research efforts have focused on the placement of sensor systems to aid vulnerability assessments associated with contamination events. A related issue is the probability of isolating a contaminant following sensor detection. In this current effort, we utilize three optimization techniques: (1) an unconstrained first-order reliability method (FORM); (2) a constrained FORM; and (3) parameter estimation (PEST), to determine the optimal demand to reduce contaminant concentration. This aids in consequence management of contamination events by supplying water distribution system operators with additional information to remediate contaminated sections. Application of these techniques to a relatively simple network and a moderately complex network demonstrates the usefulness of optimization methods in determining optimal demands in order to reduce contaminant concentration. Although each of the techniques performed well for this example, PEST illustrated greater capabilities in determining the most optimal solution. |
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| publications-4127 |
article |
2013 |
Hung, Mingβ€Feng and Hung, Ming-Feng and Chie, Binβ€Tzong and Chie, Bin-Tzong |
Residential Water Use: Efficiency, Affordability, and Price Elasticity |
Water Resources Management |
10.1007/s11269-012-0185-z |
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In practice, water pricing is the main economic instrument used to discourage the wasteful use of residential water. Owing to considerations of affordability, residential water is systematically underpriced because water is essential for life. Such a low price results in water being used inefficiently. This paper proposes a system that supplements the existing price system with a cap-and-trade measure to reconcile conflicts among the goals of residential water use. It forces all people (independent of income) to be faced with reasonable price signals and to use water efficiently. The poor could, however, gain from trade and afford water. By taking advantage of the agent-based model, a simulation of this system applied to Taipei, Taiwan shows that those with lower income per capita are better off under this system even though the equilibrium price of residential water is higher. The simulated average price elasticity of market demand is β’0.449. |
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| publications-4128 |
article |
2013 |
Zhao, Jianshi and Zhao, Jianshi and Cai, Ximing and Cai, Ximing and Wang, Zhongjing and Wang, Zhongjing |
Comparing administered and market-based water allocation systems through a consistent agent-based modeling framework. |
Journal of Environmental Management |
10.1016/j.jenvman.2013.03.005 |
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| publications-4129 |
article |
2012 |
Perelman, Lina and Ostfeld, Avi |
Extreme Impact Contamination Events Sampling for Real-Sized Water Distribution Systems |
Journal of Water Resources Planning and Management |
10.1061/(asce)wr.1943-5452.0000206 |
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AbstractContamination warning systems are being designed to protect water distribution systems against deliberate contamination intrusions. To design a contamination warning system, contamination intrusion events need to be selected. Because contamination intrusions are random, even for a medium-size network the theoretical number of possible injection events is huge, and thus the number of contamination events which can be considered in the design process is limited. To effectively cope with the threat of contamination events there is a need to identify those critical instances. A straightforward approach of enumerating all possible contamination intrusions from which critical events can be selected is limited to small systems. As critical events are rare the probability of revealing them using common Monte Carlo randomized simulations is very small or requires an extensive impractical computational amount of trials. In this study a methodology utilizing importance sampling and cross entropy based on a r... |
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| publications-4130 |
article |
2014 |
Crooks, Andrew and Crooks, Andrew and Hailegiorgis, Atesmachew and Hailegiorgis, Atesmachew B. |
An agent-based modeling approach applied to the spread of cholera |
Environmental Modelling and Software |
10.1016/j.envsoft.2014.08.027 |
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