1,785,430 research outputs found
Within- and between-pen transmission of Classical Swine Fever Virus: a new method to estimate the basic reproduction ratio from transmission experiments
We present a method to estimate basic reproduction ratio R0 from transmission experiments. By using previously published data of experiments with Classical Swine Fever Virus more extensively, we obtained smaller confidence intervals than the martingale method used in the original papers. Moreover, our method allows simultaneous estimation of a reproduction ratio within pens R0w and a modified reproduction ratio between pens R'0b. Resulting estimates of R0w and R'0b for weaner pigs were 100 (95% CI 54.4-186) and 7.77 (4.68-12.9), respectively. For slaughter pigs they were 15.5 (6.20-38.7) and 3.39 (1.54-7.45), respectively. We believe, because of the smaller confidence intervals we were able to obtain, that the method presented here is better suited for use in future experiments
An application of the variable-r method to subpopulation growth rates in a 19th century agricultural population
This paper presents an analysis of the differential growth rates of the farming and non-farming segments of a rural Scottish community during the 19th and early 20th centuries using the variable-r method allowing for net migration. Using this method, I find that the farming population of Orkney, Scotland, showed less variability in their reproduction and growth rates than the non-farming population during a period of net population decline. I conclude by suggesting that the variable-r method can be used in general cases where the relative growth of subpopulations or subpopulation reproduction is of interest.agricultural population, Scotland, subpopulation growth rates, variable-r method
Apocalypse and recuperation: Blake and the maw of commerce
The paper is a "materialist" reading of Blake's illuminated works. It examines the copperplate method itself as the main theme of Blake's work, and also as a potentially practical means of conveying Blake's art to its intended audience. The question of audience must be at the center of any avowedly prophetic project. Did Blakean production actually facilitate reception? Are we the audience it sought? What forms of supplementary reproduction are necessary for modern discourse on Blake, and what are the effects of such mediation? To what extent does reproduction undermine. sublate, cancel or recuperate Blakean priorities even as it seeks to represent them? What do we actually read when we read a reproduction? The paper also thinks through the Blakean problem to a broader consideration of artistic projects operating marginally to the predominant cultural economy. and of their relation to criticism
A rigorous evaluation of crossover and mutation in genetic programming
The role of crossover and mutation in Genetic Programming (GP) has been the subject of much debate since the emergence of the field. In this paper, we contribute new empirical evidence to this argument using a rigorous and principled experimental method applied to six problems common in the GP literature. The approach tunes the algorithm parameters to enable a fair and objective comparison of two different GP algorithms, the first using a combination of crossover and reproduction, and secondly using a combination of mutation and reproduction. We find that crossover does not significantly outperform mutation on most of the problems examined. In addition, we demonstrate that the use of a straightforward Design of Experiments methodology is effective at tuning GP algorithm parameters
Optimization method for the determination of material parameters in damaged composite structures
An optimization method to identify the material parameters of composite structures using an inverse method is proposed. This methodology compares experimental results with their numerical reproduction using the finite element method in order to obtain an estimation of the error between the results. This error estimation is then used by an evolutionary optimizer to determine, in an iterative process, the value of the material parameters which result in the best numerical fit. The novelty of the method is in the coupling between the simple genetic algorithm and the mixing theory used to numerically reproduce the composite behavior. The methodology proposed has been validated through a simple example which illustrates the exploitability of the method in relation to the modeling of damaged composite structures.Peer ReviewedPostprint (author’s final draft
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