Siting Samplers to Minimize Expected Time to Detection

We present a probabilistic approach to designing an indoor sampler network for detecting an accidental or intentional chemical or biological release, and demonstrate it for a real building. In an earlier article, Sohn and Lorenzetti developed a proof of concept algorithm that assumed samplers could return measurements only slowly (on the order of hours). This led to optimal “detect to treat” architectures that maximize the probability of detecting a release. This article develops a more general approach and applies it to samplers that can return measurements relatively quickly (in minutes). This leads to optimal “detect to warn” architectures that minimize the expected time to detection. Using a model of a real, large, commercial building, we demonstrate the approach by optimizing networks against uncertain release locations, source terms, and sampler characteristics. Finally, we speculate on rules of thumb for general sampler placement.     

Empirical bayes estimation of the binomial parameter n

Estimation of the prior distribution of the binomial parameter nbased on a system of orthogonal polynomials, the Poisson-Charlier polynomials, is studied. It is shown that the resulting estimator is mean squared consistent with rate O(N ^ε-1), where Nis the sample size and ε> 0 is arbitrarily small.     

Another twist on the equality of OLS and GLS

We give a neccessary and sufficient condition for the equality of theOLS andGLS estimator of a subset of the regression coefficients in a linear model.     

Images of Success: How Illinois Farmers Define the Successful Farmer1

Abstract Farmers' views of farming success help frame their responses to information about farming, including alternative agriculture. A Q-analysis of 68 commercial farmers' subjective images of the successful farmer and the relative importance they accord different personal values and characteristics revealed four “model” images of the successful farmer. The Steward recognizes a moral responsibility to sustain land resources; the Manager succeeds largely by virtue of analytical skill; the Conservative's main goal is long-term preservation of the farm business; and the Agrarian values the rural life style and community participation. Farmers holding the Steward image tended to be older and to farm fewer acres; those with the Manager image included a large proportion of less experienced farmers. Approximately 40 percent of the farmers' views of success did not fit any of the four “model” images. Analysis of the findings suggests that images of success may be associated with life stage or generational differences in farming goals and values.     

A universal meta bargaining implementation of the Nash solution

This paper follows van Damme (1986) in presenting a meta bargaining approach that justifies the Nash bargaining solution. But in contrast to van Damme's procedure our meta bargaining game is universal in the sense that all bargaining solutions are allowed as strategic choices in the meta bargaining game. Also our result holds true for any number n of players. Received: 31 July 2000/Accepted: 19 March 2001