The Palaeo-Agulhas Plain formed an important habitat exploited by Pleistocene hunter-gatherer populations during periods of lower sea level. This productive, grassy habitat would have supported numerous large-bodied ungulates accessible to a population of skilled hunters with the right hunting technology. It also provided a potentially rich location for plant food collection, and along its shores a coastline that moved with the rise and fall of sea levels. The rich archaeological and paleontological records of Pleistocene sites along the modern Cape south coast of South Africa, which would have overlooked the Palaeo-Agulhas Plain during Pleistocene times of lower sea level, provides a paleoarchive of this extinct ecosystem. In this paper, we present a first order illustration of the “palaeoscape modeling” approach advocated by Marean et al. (2015). We use a resourcescape model created from modern studies of habitat productivity without the Palaeo-Agulhas Plain. This is equivalent to predominant Holocene conditions. We then run an agent-based model of the human foraging system to investigate several research questions. Our agent-based approach uses the theoretical framework of optimal foraging theory to model human foraging decisions designed to optimize the net caloric gains within a complex landscape of spatially and temporally variable resources. We find that during the high sea-levels of MIS 5e (+5-6 m asl) and the Holocene, the absence of the Plain left a relatively poor food base supporting a much smaller population relying heavily on edible plant resources from the current Cape flora. Despite high species diversity of plants with edible storage organs, and marine invertebrates, encounter rates with highly profitable resources were low. We demonstrate that without the Palaeo-Agulhas Plain, human populations must have been small and low density, and exploited plant, mammal, and marine resources with relatively low caloric returns. The exposure and contraction of the Palaeo-Agulhas Plain was likely the single biggest driver of behavioral change during periods of climate change through the Pleistocene and into the transition to the Holocene.

The model is then used for assessing three hypothetical and contrasted infrastructure-oriented adaptation strategies for the winter tourism industry, that have been previously discussed with local stakeholders, as possible alternatives to the “business-as-usual” situation.

Abstract: The notion of physical space has long been central in geographical theories. However, the widespread adoption of information and communication technologies (ICTs) has freed human dynamics from purely physical to also relational and cyber spaces. While researchers increasingly recognize such shifts, rarely have studies examined how the information propagates in these hybrid spaces (i.e., physical, relational, and cyber). By exploring the vaccine opinion dynamics through agent-based modeling, this study is the first that combines all hybrid spaces and explores their distinct impacts on human dynamics from an individual’s perspective. Our model captures the temporal dynamics of vaccination progress with small errors (MAE=2.45). Our results suggest that all hybrid spaces are indispensable in vaccination decision making. However, in our model, most of the agents tend to give more emphasis to the information that is spread in the physical instead of other hybrid spaces. Our study not only sheds light on human dynamics research but also offers a new lens to identifying vaccinated individuals which has long been challenging in disease-spread models. Furthermore, our study also provides responses for practitioners to develop vaccination outreach policies and plan for future outbreaks.

This model played a small part in the UK government’s review of the working of local authority implementation of the Domestic Abuse legislation. The model explicitly represents victim-survivor families as they: (a) try to contact the local DA support system, (b) are triaged by the system and (if there is space) allocated to safe temporary accomodation (c) recieve support services from this position and (d) eventually move on to more permenant accomodation. The purpose of the model was to understand some possible ways in which the implementation of DA Duty, might be frustrated in practice, the identification of gaps in the evidence base and to inform the developing Theory of Change. The key measures used for assessing outcomes in the model were the number of families helped and the services that were delivered to them. The exploration was grounded for in two archetypal cases: that of a relatively immature system for the delivery of DA services and a more mature one (based on actual local authority cases, but not based on any single one). See the official report under associated publications for a summary of results.

This paper tries to shed some light on the mutual influence of citizen behaviour and the spread of a virus in an epidemic. While the spread of a virus from infectious to susceptible persons and the outbreak of an infection leading to more or less severe illness and, finally, to recovery and immunity or death has been modelled with different kinds of models in the past, the influence of certain behaviours to keep the epidemic low and to follow recommendations of others to apply these behaviours has rarely been modelled. The model introduced here uses a theory of the effect of norm invocations among persons to find out the effect of spreading norms interacts with the progress of an epidemic. Results show that norm invocations matter. The model replicates the histories of the COVID-19 epidemic in various region, including “second waves” (but only until the end of 2021 as afterwards the official statistics ceased to be reliable as many infected persons did not report their positive test results after countermeasures were relieved), and shows that the calculation of the reproduction numbers from current reported infections usually overestimates the “real” but in practice unobservable reproduction number.

This model describes and analyses the Travel-Tour Case study.

Manipulate[
Module[{fDot, mDot, poly, roots, stableRoots, rStar, rIso,
endPointStar, endPointIso},(1. Define the System Dynamics)
fDot = phi1(f/m) - phi2(m/f);
mDot = mu1(f/m) - mu2(m/f);
(*2. Find the Equilibrium Ratio r=f/
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This model is an extension of Wilensky’s (2003) Traffic Grid, a foundational NetLogo model of urban traffic flow. It embeds a dual-process cognitive architecture into each driver agent, transforming the original’s identical reactive units into cognitively heterogeneous individuals whose internal mental state evolves with experience; making the same intersection produce different decisions from different drivers, and different decisions from the same driver across occasions.
The core question the model addresses is the yellow-light dilemma zone: the seconds following amber onset in which a driver can neither stop safely nor clear the intersection before red. Field research documents that behavioral variance at this moment cannot be explained by geometry or legal obligation alone. This model provides the cognitive architecture that has been missing from traffic ABMs.
Each driver routes every amber-onset decision through either System 1 (fast, heuristic, automatic) or System 2 (slow, deliberative, prospect-theoretic), switching dynamically based on cognitive load, accumulated near-miss memory, and situational framing. The result is crash outcomes that are attributable, path-dependent, and sensitive to both driver disposition and signal infrastructure; none of which fixed-rule models can reproduce. Three signal control modes are included: fixed-cycle (replicating Wilensky’s original), adaptive-queue, and smart occupancy-based switching.

Reducing packaging waste is a critical challenge that requires organizations to collaborate within circular ecosystems, considering social, economic, and technical variables like decision-making behavior, material prices, and available technologies. Agent-Based Modeling (ABM) offers a valuable methodology for understanding these complex dynamics. In our research, we have developed an ABM to explore circular ecosystems’ potential in reducing packaging waste, using a case study of the Dutch food packaging ecosystem. The model incorporates three types of agents—beverage producers, packaging producers, and waste treaters—who can form closed-loop recycling systems.

Beverage Producer Agents: These agents represent the beverage company divided into five types based on packaging formats: cans, PET bottles, glass bottles, cartons, and bag-in-boxes. Each producer has specific packaging demands based on product volume, type, weight, and reuse potential. They select packaging suppliers annually, guided by deterministic decision styles: bargaining (seeking the lowest price) or problem-solving (prioritizing high recycled content).

Packaging Producer Agents: These agents are responsible for creating packaging using either recycled or virgin materials. The model assumes a mix of monopolistic and competitive market situations, with agents calculating annual material needs. Decision styles influence their choices: bargaining agents compare recycled and virgin material costs, while problem-solving agents prioritize maximum recycled content. They calculate recycled content in packaging and set prices accordingly, ensuring all produced packaging is sold within or outside the model.

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Agent-Based-Modeling - space colonization
ask me for the .nlogo model
WHAT IS IT?
The goal of this project is to simulate with NetLogo (v6.2) a space colonization of humans, starting from Earth, into the Milky Way.

HOW IT WORKS
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