Computational Model Library

Displaying 10 of 156 results for "Uta Berger" clear search

Game of Thrones model

Claudine Gravel-Miguel Sean Bergin | Published Sunday, January 03, 2021 | Last modified Sunday, January 03, 2021

This model slowly evolves to become Westeros, with houses fighting for the thrones, and whitewalkers trying to kill all living things. You can download each version to see the evolution of the code, from the Wolf Sheep Predation model to the Game of Thrones model. If you are only interested in the end product, simply download the latest version.

For instructions on each step, see: https://claudinegravelmigu.wixsite.com/got-abm

I model a forest and a community of loggers. Agents follow different kinds of rules in order to log. I compare the impact of endogenous and of exogenous institutions on the state of the forest and on the profit of the users, representing different scenarios of participatory conservation projects.

This model, realized on the NetLogo platform, compares utility levels at home and abroad to simulate agents’ migration and their eventual return. Our model is based on two fundamental individual features, i.e. risk aversion and initial expectation, which characterize the dynamics of different agents according to the evolution of their social contacts.

This work aims at describing and simulating the (social) game around the production of potato seeds in Venezuela. It shows the effect of the identification of some actors with the production of native potato seeds (e.g., Venezuelan State´s low ident)

The simulation is a variant of the “ToRealSim OD variants - base v2.7” base model, which is based on the standard DW opinion dynamics model (but with the differences that rather than one agent per tick randomly influencing another, all agents randomly influence one other per tick - this seems to make no difference to the outcomes other than to scale simulation time). Influence can be made one-way by turning off the two-way? switch

Various additional variations and sources of noise are possible to test robustness of outcomes to these (compared to DW model).
In this version agent opinions change following the empirical data collected in some experiments (Takács et al 2016).

Such an algorithm leaves no role for the uncertainties in other OD models. [Indeed the data from (Takács et al 2016) indicates that there can be influence even when opinion differences are large - which violates a core assumption of these]. However to allow better comparison with other such models there is a with-un? switch which allows uncertainties to come into play. If this is on, then influence (according to above algorithm) is only calculated if the opinion difference is less than the uncertainty. If an agent is influenced uncertainties are modified in the same way as standard DW models.

Correlated random walk

Thibault Fronville | Published Friday, April 01, 2022 | Last modified Monday, April 25, 2022

The first simple movement models used unbiased and uncorrelated random walks (RW). In such models of movement, the direction of the movement is totally independent of the previous movement direction. In other words, at each time step the direction, in which an individual is moving is completely random. This process is referred to as a Brownian motion.
On the other hand, in correlated random walks (CRW) the choice of the movement directions depends on the direction of the previous movement. At each time step, the movement direction has a tendency to point in the same direction as the previous one. This movement model fits well observational movement data for many animal species.
The presented agent based model simulated the movement of the agents as a correlated random walk (CRW). The turning angle at each time step follows the Von Mises distribution with a ϰ of 10. The closer ϰ gets to zero, the closer the Von Mises distribution becomes uniform. The larger ϰ gets, the more the Von Mises distribution approaches a normal distribution concentrated around the mean (0°).
This model is implemented in python and can be used as a building block for more complex agent based models that would rely on describing the movement of individuals with CRW.

The model is based on the influence function of the Leviathan model (Deffuant, Carletti, Huet 2013 and Huet and Deffuant 2017) with the addition of group idenetity. We aim at better explaining some patterns generated by this model, using a derived mathematical approximation of the evolution of the opinions averaged.

We consider agents having an opinion/esteem about each other and about themselves. During dyadic meetings, agents change their respective opinion about each other, and possibly about other agents they gossip about, with a noisy perception of the opinions of their interlocutor. Highly valued agents are more influential in such encounters. Moreover, each agent belongs to a single group and the opinions within the group are attracted to their average.

We show that a group hierarchy can emerges from this model, and that the inequality of reputations among groups have a negative effect on the opinions about the groups of low status. The mathematical analysis of the opinion dynamic shows that the lower the status of the group, the more detrimental the interactions with the agents of other groups are for the opinions about this group, especially when gossip is activated. However, the interactions between agents of the same group tend to have a positive effect on the opinions about this group.

Prior to COVID-19, female academics accounted for 45% of assistant professors, 37% of associate professors, and 21% of full professors in business schools (Morgan et al., 2021). The pandemic arguably widened this gender gap, but little systemic data exists to quantify it. Our study set out to answer two questions: (1) How much will the COVID-19 pandemic have impacted the gender gap in U.S. business school tenured and tenure-track faculty? and (2) How much will institutional policies designed to help faculty members during the pandemic have affected this gender gap? We used agent-based modeling coupled with archival data to develop a simulation of the tenure process in business schools in the U.S. and tested how institutional interventions would affect this gender gap. Our simulations demonstrated that the gender gap in U.S. business schools was on track to close but would need further interventions to reach equality (50% females). In the long-term picture, COVID-19 had a small impact on the gender gap, as did dependent care assistance and tenure extensions (unless only women received tenure extensions). Changing performance evaluation methods to better value teaching and service activities and increasing the proportion of female new hires would help close the gender gap faster.

Network-Based Trust Games

Bin-Tzong Chie | Published Thursday, August 22, 2013 | Last modified Wednesday, April 15, 2020

The network-based trust game is a hybridization of both the repeated trust games and the network games.

code for graphical output

Mert Edali Hakan Yasarcan | Published Wednesday, November 05, 2014

This is the R code of the mathematical model that includes the decision making formulations for artificial agents. Plus, the code for graphical output is also added to the original code.

Displaying 10 of 156 results for "Uta Berger" clear search

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