Papers by Jeffrey Simonoff
The age of U.S. infrastructure connects in subtle ways with many other threats such as terrorism,... more The age of U.S. infrastructure connects in subtle ways with many other threats such as terrorism, natural hazards, and climate change that these facilities and services face. Many new infrastructure initiatives being introduced to address these threats are also likely to address many of the condition and performance problems of aging infrastructure. This paper evaluates a number of infrastructure areas
This research work has developed methodologies to enhance the ability of decision-makers to distr... more This research work has developed methodologies to enhance the ability of decision-makers to distribute resources for security by (a) estimating critical infrastructure densities around hypothetical vulnerable sites as a basis for risk-based resource allocation; and (b) summarizing and evaluating the conceptual and practical soundness of critical infrastructure density estimates applicable to a wide variety of infrastructures. The methodology to estimate
Social and economic consequences of a terrorist attack on a vulnerable site can magnify impacts b... more Social and economic consequences of a terrorist attack on a vulnerable site can magnify impacts by indirectly damaging nearby critical infrastructure systems. This work extended research conducted in Years 4 and 5 on the implications of proximity and concentration of infrastructure facilities for nearby vulnerable sites. Metrics and models are necessary to approach this problem. This work is applicable to
Public and private decision-makers continue to seek risk-based approaches to allocating funds to ... more Public and private decision-makers continue to seek risk-based approaches to allocating funds to secure facilities that are potentially vulnerable to terrorist attacks. An important input into decisions about allocating funds for security is the density of critical infrastructure around facilities that could be potential targets of an attack. A terrorist attack on a vulnerable facility located in the vicinity of
Incident data about disruptions to the electric power grid provide useful information that can be... more Incident data about disruptions to the electric power grid provide useful information that can be used as inputs into risk management policies in the energy sector for disruptions from a variety of origins including terrorist attacks. This paper uses data from the Disturbance Analysis Working Group (DAWG) database, which is maintained by the North American Electric Reliability Council (NERC) to
Proceedings of the 39th Annual Hawaii International Conference on System Sciences (HICSS'06), 2006
Interdependencies among infrastructure systems are now becoming commonplace, and present both opp... more Interdependencies among infrastructure systems are now becoming commonplace, and present both opportunities and vulnerabilities. Initial attention was paid to functional interdependencies among infrastructure systems regardless of locational characteristics. Using electric power as a focal point, geographic interdependencies are evaluated, that is, outages that spread across several states rather than being confined to single states. The analysis evaluates the extent to which the two different groups have distinct characteristics. The characteristics examined include incident counts, number of customers lost, duration and energy unserved. Data are drawn from the Disturbance Analysis Working Group (DAWG) database, which is maintained by the North American Electric Reliability Council (NERC), and from the U.S. Energy Information Administration (EIA).
Statistical Thinking in Sports, 2007
International Journal of Critical Infrastructure Protection, 2009
that result in the unplanned release of hazardous liquids are examined. Understanding how differe... more that result in the unplanned release of hazardous liquids are examined. Understanding how different causes of accidents are associated with consequence measures can provide important inputs into risk management for this (and other) critical infrastructure systems. Data on 1582 accidents related to hazardous liquid pipelines for the period 2002-2005 are analyzed. The data were obtained from the US Department of Transportation's Office of Pipeline Safety (OPS). Of the 25 different causes of accidents included in the data the most common ones are equipment malfunction, corrosion, material and weld failures, and incorrect operation. This paper focuses on one type of consequence -various costs associated with these pipeline accidents -and causes associated with them. The following economic consequence measures related to accident cost are examined: the value of the product lost; public, private, and operator property damage; and cleanup, recovery, and other costs. Logistic regression modeling is used to determine what factors are associated with nonzero product loss cost, nonzero property damage cost and nonzero cleanup and recovery costs. The factors examined include the system part involved in the accident, location characteristics (offshore versus onshore location, occurrence in a high consequence area), and whether there was liquid ignition, an explosion, and/or * Corresponding author. Tel.: +1 212 992 9867; fax: +1 212 995 4875.
The Economic Costs and Consequences of Terrorism, 2007
IFIP International Federation for Information Processing, 2007
This paper examines the spatial and temporal distribution of failures in three critical infrastru... more This paper examines the spatial and temporal distribution of failures in three critical infrastructure systems in the United States: the electrical power grid, hazardous liquids (including oil) pipelines, and natural gas pipelines. The analyses are carried out at the state level, though the analytical frameworks are applicable to other geographic areas and infrastructure types. The paper also discusses how understanding the spatial distribution of these failures can be used as an input into risk management policies to improve the performance of these systems, as well as for security and natural hazards mitigation.
This paper studies the asymptotic and nite-sample performance ofpenalized regression methods when... more This paper studies the asymptotic and nite-sample performance ofpenalized regression methods when different selectors of theregularization parameter are used under the assumption that the truemodel is, or is not, included among the candidate model. In the lattersetting, we relax assumptions in the existing theory to show thatseveral classical information criteria are asymptotically efficientselectors of the regularization parameter. In both settings,
Zoo Biology, 1997
... Analytical Software. STATISTIX version 4.0, St. Paul, MN, Analytical Software, 1992. Asper, E... more ... Analytical Software. STATISTIX version 4.0, St. Paul, MN, Analytical Software, 1992. Asper, ED; Young, WG; Walsh, MT Observa-tions on the birth and development of a cap-tive-born whale. INTERNATIONAL ZOO YEARBOOK 27:295304, 1988. Page 14. 260 Russell et al. ...
Technometrics, 2002
The single index model is a generalization of the linear regression model with E4y-x5 D g4x 0 ‚5,... more The single index model is a generalization of the linear regression model with E4y-x5 D g4x 0 ‚5, where g is an unknown function. The model provides a exible alternative to the linear regression model while providing more structure than a fully nonparametric approach. Although the tting of single index models does not require distributional assumptions on the error term, the properties of the estimates depend on such assumptions, as does practical application of the model. In this article score tests are derived for three potential misspeci cations of the single index model: heteroscedasticity in the errors, autocorrelation in the errors, and the omission of an important variable in the linear index. These tests have a similar structure to corresponding tests for nonlinear regression models. Monte Carlo simulations demonstrate that the rst two tests hold their nominal size well and have good power properties in identifying model violations, often outperforming other tests. Testing for the need for additional covariates can be effective, but is more dif cult. The score tests are applied to three real datasets, demonstrating that the tests can identify important model violations that affect inference, and that approaches that do not take model misspeci cations into account can lead to very different results.
Risk Analysis, 2007
Incident data about disruptions to the electric power grid provide useful information that can be... more Incident data about disruptions to the electric power grid provide useful information that can be used as inputs into risk management policies in the energy sector for disruptions from a variety of origins including terrorist attacks. This paper uses data from the Disturbance Analysis Working Group (DAWG) database, which is maintained by the North American Electric Reliability Council (NERC) to look at incidents over time in the United States and Canada for the period 1990-2004. Negative binomial regression, logistic regression and weighted least squares regression are used to gain a better understanding of how these disturbances varied over time and by season during this period, and to analyze how characteristics such as number of customers lost and outage duration are related to different characteristics of the outages. The results of the models can be used as inputs to construct various scenarios to estimate potential outcomes of electric power outages, encompassing the risks, consequences, and costs of such outages.
Research in Higher Education, 2012
ABSTRACT The purpose of this paper was to explore innovative entrepreneurship and to gain insight... more ABSTRACT The purpose of this paper was to explore innovative entrepreneurship and to gain insight into the educational practices and experiences that increase the likelihood that a student would graduate with innovative entrepreneurial intentions. To this end, we administered a battery of assessments to 3,700 undergraduate seniors who matriculated in the spring of 2007; these students attended one of five institutions participating in this study. Results showed that, after controlling for a host of personality, demographic, educational, and political covariates, taking an entrepreneurial course and the assessments faculty use as pedagogical strategies for teaching course content were significantly related to innovation intentions. Implications for higher education stakeholders are discussed.
Naval Research Logistics, 2006
This paper discusses a novel application of mathematical programming techniques to a regression p... more This paper discusses a novel application of mathematical programming techniques to a regression problem. While least squares regression techniques have been used for a long time, it is known that their robustness properties are not desirable. Specifically, the estimators are known to be too sensitive to data contamination. In this paper we examine regressions based on Least-sum of Absolute Deviations (LAD) and show that the robustness of the estimator can be improved significantly through a judicious choice of weights. The problem of finding optimum weights is formulated as a nonlinear mixed integer program, which is too difficult to solve exactly in general. We demonstrate that our problem is equivalent to one similar to the knapsack problem and then solve it for a special case. We then generalize this solution to general regression designs. Furthermore, we provide an efficient algorithm to solve the general non-linear, mixed integer programming problem when the number of predictors is small. We show the efficacy of the weighted LAD estimator using numerical examples.
Machine Learning, 2012
Longitudinal data refer to the situation where repeated observations are available for each sampl... more Longitudinal data refer to the situation where repeated observations are available for each sampled object. Clustered data, where observations are nested in a hierarchical structure within objects (without time necessarily being involved) represent a similar type of situation. Methodologies that take this structure into account allow for the possibilities of systematic differences between objects that are not related to attributes
Journal of the American Statistical Association, 1993
Procedures for the Identification of Multiple Outliers in Linear Models Ali S. Hadi and Jeffrey S... more Procedures for the Identification of Multiple Outliers in Linear Models Ali S. Hadi and Jeffrey S. Simonoff* We consider the problem of identifying and testing ...
Journal of Computational and Graphical Statistics, 1999
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Papers by Jeffrey Simonoff