Interaction between scale and scheduling choices in simulations of spatial agents

Authored by Raja Sengupta, Tyler R Bonnell, Colin A Chapman

Date Published: 2016

DOI: 10.1080/13658816.2016.1158822

Sponsors: National Science and Engineering Research Council of Canada (NSERC) Fonds de Recherche Nature et Technologies

Platforms: Repast Java R

Model Documentation: Other Narrative Flow charts

Model Code URLs: Model code not found

Abstract

Spatial simulations are a valuable tool in understanding dynamic spatial processes. In developing these simulations, it is often required to make decisions about how to represent features in the environment and how events unfold in time. These spatial and temporal choices have been shown to significantly alter model outcomes, yet their interaction is less well understood. In this paper, we make use of a simple group foraging model and systematically vary how features are represented (cell size of the landscape) as well as how events unfold in time (order in which foragers take action) to better understand their interaction. Our results show similar nonlinear responses to changes in spatial representation found in the literature, and an effect of the order in which agents were processed. There was also a clear interaction between how features are represented and how events unfold in time, where, under certain environmental representations results were found to be more sensitive to the order in which individuals were processed. Furthermore, the effects of feature representation, scheduling of agents, and their interaction were all found to be influenced by the heterogeneity of the spatial surface (food), suggesting that the statistical properties of the underlying spatial variable will additionally play a role. We suggest that navigating these interactions can be facilitated through a better understanding of how these choices affect the decision landscape(s) on which agents operate. Specifically, how changes to representation affect aggregation and resolution of the decision surface, and thereby the degree to which agents interact directly or indirectly. We suggest that the challenges of dealing with spatial representation, scheduling, and their interaction, while building models could also present an opportunity. As explicitly including alternate representations and scheduling choices during model selection can aid in identifying optimal agent-environment representations. Potentially leading to improved insights into the relationships between spatial processes and the environments in which they occur.

Tags

models Land-use ecology systems Decisions Sensitivity-analysis