Scott Ferson

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This report summarizes a variety of the most useful and commonly applied methods for obtaining Dempster-Shafer structures, and their mathematical kin probability boxes, from empirical information or theoretical knowledge. The report includes a review of the aggregation methods for handling agreement and conflict when multiple such objects are obtained from(More)
Modeling and simulation efforts continue to expand in areas where they have been used for some time, and they are also beginning to be used in new application areas. Modeling and simulation have been heavily used in risk assessment for high-consequence systems, such as nuclear power reactors, underground storage of radioactive wastes, and the nuclear weapon(More)
The World Conservation Union (IUCN) defined a set of categories for conservation status supported by decision rules based on thresholds of parameters such as distributional range, population size, population history, and risk of extinction. These rules have received international acceptance and have become one of the most important decision tools in(More)
Uncertainty is very important in risk analysis. A natural way to describe this uncertainty is to describe a set of possible values of each unknown quantity (this set is usually an interval), plus any additional information that we may have about the probability of different values within this set. Traditional statistical techniques deal with the situations(More)
Ecotones are inherent features of landscapes, transitional zones, and play more than one functional role in ecosystem dynamics. The delineation of ecotones and environmental boundaries is therefore an important step in land-use management planning. The delineation of ecotones depends on the phenomenon of interest and the statistical methods used as well as(More)
When we have only interval ranges [<i>x<inf>i</inf>,</i> <i>x<inf>i</inf></i>] of sample values <i>x</i><inf>1</inf>,&#8230;, <i>x<inf>n</inf>,</i> what is the interval [<i>V, V</i>] of possible values for the variance <i>V</i> of these values? We prove that the problem of computing the upper bound <i>V</i> is NP-hard. We provide a feasible (quadratic time)(More)
In this paper, we start research into using intervals to bound the impact of bounded measurement errors on the computation of bounds on finite population parameters (“descriptive statistics”). Specifically, we provide a feasible (quadratic time) algorithm for computing the lower bound σ on the finite population variance function of interval data. We prove(More)
Probability bounds analysis (PBA) provides analysts a convenient means to characterize the neighborhood of possible results that would be obtained from plausible alternative inputs in probabilistic calculations. We show the relationship between PBA and the methods of interval analysis and probabilistic uncertainty analysis from which it is jointly derived,(More)
This report summarizes methods to incorporate information (or lack of information) about inter-variable dependence into risk assessments that use Dempster-Shafer theory or probability bounds analysis to address epistemic and aleatory uncertainty. The report reviews techniques for simulating correlated variates for a given correlation measure and dependence(More)