Inspections to Avert Terrorism: Robustness Under Severe Uncertainty

Moffitt, L. Joe; Stranlund, John K.; Field, Barry C.

doi:10.2202/1547-7355.1134

Cited by 23 publications

(13 citation statements)

References 12 publications

(9 reference statements)

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“…Preventing illicit nuclear materials from entering the US has become a prominent issue not only in the security community (Cochran and McKinzie 2008;Fritelli 2005;Moffitt et al 2005), but also the academic community. Several researchers have applied operations research methodologies to the problem of preventing nuclear materials smuggling.…”

Section: Related Workmentioning

confidence: 99%

Detecting nuclear materials smuggling: using radiography to improve container inspection policies

Gaukler

Cannaday

et al. 2010

Ann Oper Res

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This paper proposes a layered container inspection system for detecting illicit nuclear materials using radiography information. We argue that the current inspection system, relying heavily on the Automated Targeting System (ATS) and passive radiation detectors, is inherently incapable of reliably detecting shielded radioactive materials, especially highly enriched uranium (HEU). This motivates the development of a new inspection system, which is designed to address a fundamental flaw of the ATS-based system, allowing for improved defense against sophisticated adversaries. In the proposed inspection system, all cargo containers go through x-ray imaging equipment first. From the x-ray image, a hardness measure of the container is computed. This hardness measure characterizes how likely it is that shielded HEU, if it does exist in the container, will not be detected in a subsequent passive detection step. Depending on the value of the hardness, the lower-hardness containers are sent to passive detection and the high-hardness containers are sent directly to active detection. This paper explores the trade-off between the detection probability of the new inspection system and the expected sojourn time a container spends in the system. The solution details and decision-making tools for using such a system are provided. Comparisons are made between the proposed system and the current ATS-based nuclear inspection system.

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Section: Related Workmentioning

confidence: 99%

Detecting nuclear materials smuggling: using radiography to improve container inspection policies

Gaukler

Cannaday

et al. 2010

Ann Oper Res

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“…An even more general info gap model would abandon all parametric assumptions. Such an approach was adopted by Moffitt et al [2005] where the distributions were restricted simply by making all probabilities positive and by setting the total mass below the probability curve to unity. Here we have preferred to continue to work within an, albeit rather general, parametric family of distributions but to make only minimal assumptions about the distribution of errors.…”

Section: Discussionmentioning

confidence: 99%

Information gap analysis of flood model uncertainties and regional frequency analysis

Hine

Hall

2010

Water Resources Research

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[1] Flood risk analysis is subject to often severe uncertainties, which can potentially undermine flood management decisions. This paper explores the use of information gap theory to analyze the sensitivity of flood management decisions to uncertainties in flood inundation models and flood frequency analysis. Information gap is a quantified nonprobabilistic theory of robustness. To analyze uncertainties in flood modeling, an energy-bounded information gap model is established and applied first to a simplified uniform channel and then to a more realistic 2-D flood model. Information gap theory is then applied to the estimation of flood discharges using regional frequency analysis. The use of an information gap model is motivated by the notion that hydrologically similar sites are clustered in the space of their L moments. The information gap model is constructed around a parametric statistical flood frequency analysis, resulting in a hybrid model of uncertainty in which natural variability is handled statistically while epistemic uncertainties are represented in the information gap model. The analysis is demonstrated for sites in the Trent catchment, United Kingdom. The analysis is extended to address ungauged catchments, which, because of the attendant uncertainties in flood frequency analysis, are particularly appropriate for information gap analysis. Finally, the information gap model of flood frequency is combined with the treatment of hydraulic model uncertainties in an example of how both sources of uncertainty can be accounted for using information gap theory in a flood risk management decision.

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“…Note that Ramirez-Marquez (2008) assume that various sensors screen containers in a selected order, whereas order is not a factor in CRKP. Moffitt et al (2005) develop a model using information gap decision making to determine how to inspect a number of targets to shed light on robust decisions. They find that robustness to protect against a minimum level of the expected utility is not always monotonic in the number of vessels to inspect, and they recommend developing robust inspection policies that depend on inspection costs and expected utilities.…”

Section: Introductionmentioning

confidence: 99%

Interdicting nuclear material on cargo containers using knapsack problem models

2009

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This paper introduces a framework for screening cargo containers for nuclear material at security stations throughout the United States using knapsack problem, reliability, and Bayesian probability models. The approach investigates how to define a system alarm given a set of screening devices, and hence, designs and analyzes next-generation security system architectures. Containers that yield a system alarm undergo secondary screening, where more effective and intrusive screening devices are used to further examine containers for nuclear and radiological material. It is assumed that there is a budget for performing secondary screening on containers that yield a system alarm. This paper explores the relationships and tradeoffs between prescreening, secondary screening costs, and the efficacy of radiation detectors. The key contribution of this analysis is that it provides a risk-based framework for determining how to define a system alarm for screening cargo containers given limited screening resources. The analysis suggests that highly accurate prescreening is the most important factor for effective screening, particularly when screening tests are highly dependent, and that moderately accurate prescreening may not be an improvement over treating all cargo containers the same. Moreover, it suggests that screening tests with high true alarm rates may mitigate some of the risk associated with low prescreening intelligence.

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Inspections to Avert Terrorism: Robustness Under Severe Uncertainty

Cited by 23 publications

References 12 publications

Detecting nuclear materials smuggling: using radiography to improve container inspection policies

Detecting nuclear materials smuggling: using radiography to improve container inspection policies

Information gap analysis of flood model uncertainties and regional frequency analysis

Interdicting nuclear material on cargo containers using knapsack problem models

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