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Tim Williams Member since: Friday, September 29, 2017

BE (hons) in Natural Resources Engineering

I’m a PhD student in the department of Industrial and Operations Engineering at the University of Michigan.
I am interested in issues related to risk and vulnerability in the developing world, particularly in the face of an uncertain future. In my dissertation I plan to use agent-based simulation to explore issues of food security, livelihood, and well-being of smallholder farmers in Ethiopia under different future scenarios.

Birgit Müller Member since: Wednesday, October 26, 2011 Full Member Reviewer

PhD, Head of Junior Research Group POLISES

I am currently head of the Junior Research Group POLISES which uses agent-based models to study intended and unintended effects of global policy instruments on the social-ecological resilience of smallholders. In this project, we focus on the impact of policies targeting climate risk in two common property regimes of pastoralists in Africa (Morocco and Kenya/Ethiopia).
On a conceptual level, I work in an international team of modellers, psychologists and natural scientists on adequate representations of human behaviour in agent-based models. Furthermore, I am interested in how to describe models in an appropriate and standardised manner to increase their comprehensibility and comparison.

Kristin Crouse Member since: Sunday, June 05, 2016 Full Member Reviewer

B.S. Astronomy/Astrophysics, B.A. Anthropology

I am a PhD Candidate in the Biological Anthropology program at the University of Minnesota. My research involves using agent-based models combined with field research to test a broad range of hypotheses in biology. I have created a model, B3GET, which simulates the evolution of virtual organisms to better understand the relationships between growth and development, life history and reproductive strategies, mating strategies, foraging strategies, and how ecological factors drive these relationships. I also conduct field research to better model the behavior of these virtual organisms. Here I am pictured with an adult male gelada in Ethiopia!

I specialize in writing agent-based models for both research in and the teaching of subjects including: biology, genetics, evolution, demography, and behavior.

For my dissertation research, I have produced “B3GET,” an agent-based model which simulates populations of virtual organisms evolving over generations, whose evolutionary outcomes reflect the selection pressures of their environment. The model simulates several factors considered important in biology, including life history trade-offs, investment in body size, variation in aggression, sperm competition, infanticide, and competition over access to food and mates. B3GET calculates each agent’s ‘decision-vectors’ from its diploid chromosomes and current environmental context. These decision-vectors dictate movement, body growth, desire to mate and eat, and other agent actions. Chromosomes are modified during recombination and mutation, resulting in behavioral strategies that evolve over generations. Rather than impose model parameters based on a priori assumptions, I have used an experimental evolution procedure to evolve traits that enabled populations to persist. Seeding a succession of populations with the longest surviving genotype from each run resulted in the evolution of populations that persisted indefinitely. I designed B3GET for my dissertation, but it has an indefinite number of applications for other projects in biology. B3GET helps answer fundamental questions in evolutionary biology by offering users a virtual field site to precisely track the evolution of organismal populations. Researchers can use B3GET to: (1) investigate how populations vary in response to ecological pressures; (2) trace evolutionary histories over indefinite time scales and generations; (3) track an individual for every moment of their life from conception to post-mortem decay; and (4) create virtual analogues of living species, including primates like baboons and chimpanzees, to answer species-specific questions. Users are able to save, edit, and import population and genotype files, offering an array of possibilities for creating controlled biological experiments.

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