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.

Considering that two of the three avoider species could not reach the target area in the inittial scenario, five alternative corridor scenarios were created. In all cases, we generated a greater amount of cover area under ‘Urban forest’, including elements such as scattered trees, woody plants, wooded areas, and rows of trees. This covered type was selected since all three species use it as a regular habitat. That is the second sceneario where those ecological parks and other areas inside the capital city were boostered into “urban forest patches” or buffer points, with the idea of improving the survive of the three bird species and their movement. However one of the most restrictive specie was still having movement and survival issues.

The purpose of this model is to analyze different configurations and scenarios of ecological corridors to simulate the movement of three avoider bird species at a local scale: Chondrohierax uncinatus (Accipitridae), a large carnivorous bird; Ampelion rubrocristatus (Cotingidae), a species that seeks areas with substantial land cover for refuge and rest; and Coeligena bonapartei (Trochilidae), a large hummingbird that prefers areas with a rich and diverse food supply. The model focusses on juvenile bird individuals seeking refuge and food, taking into account the mobility parameters of each species and the existing land cover types within the study area.
Specifically, the model aims to:
• Simulate the movement of 45 avoiders birds which are considered umbrella species sensitive to urban changes (which were chosen based on their specific biological and ecological requirements and parameters relevant to urban conservation efforts), 15 avoiders birds per specie to cross a two-dimensional world predominant urban.
• To be able to select which corridor scenario would be the most beneficial, in order to help the mobility of other species affected by urban fragmentation.
• Contribute to urban ecology research and support decision-making processes by relevant stakeholders.

ABMIND, the Agent-Based Model of Individual Psychological Distance, is a modeling framework developed to examine how psychological distance influences environmental protection behavior in coastal farming communities in southern China. Using household survey data and empirically estimated behavioral pathways, the model represents how uncertainty shapes four dimensions of psychological distance, namely temporal, spatial, social and hypothetical distance, and how these dimensions guide protection and degradation decisions. Agents include households, government actors and mangrove ecosystem patches, connected through social networks and ecological feedbacks that affect learning, expectations and perceived benefits. Policy interventions such as rewards, penalties and publicity guidance efforts work by modifying uncertainty and psychological distance rather than directly controlling behavior. ABMIND is implemented as a spatially explicit model following the ODD protocol, and a concise user guide is provided. In developing ABMIND we introduce a structured validation workflow that links statistical mediation analysis with simulation-based diagnostics, allowing empirical cognitive mechanisms to be systematically embedded and tested within the ABM. This integrated approach strengthens the credibility of psychological-mechanism models and supports their use in policy evaluation. The framework offers a methodological platform for integrating cognitive mechanisms into agent-based environmental behavior modeling and for evaluating policy strategies that support ecosystem protection.
Model paper:
ABMIND: An empirically informed agent-based model of psychological distance and environmental protection behaviour
Ecological Modelling
https://doi.org/10.1016/j.ecolmodel.2026.111700

This model visualizes gradient descent optimization - the fundamental algorithm used to train neural networks and other machine learning models. Agents represent different optimization algorithms searching for the minimum of a loss landscape (the “error surface” that ML models try to minimize during training).

The model demonstrates how different optimizer types (SGD, Momentum with different parameters) behave on various loss landscapes, from simple bowls to the notoriously difficult Rosenbrock “banana valley” function. This helps build intuition about why certain optimization algorithms work better than others for different problem geometries.

HOW IT WORKS

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This computational model is an agent-based model (ABM) developed to investigate how repeated failures of emerging niches accumulate and influence the trajectory of socio-technical transitions. Built in AnyLogic 8.7.11, the model simulates the dynamic interactions between a dominant regime and sequential niche entrants within a two-dimensional practice space. It models alignment, movement, and competition based on technological maturity and market penetration. The model utilizes a reinforcing feedback structure linking consumer support, output, resource accumulation, and capacity development (Physical and Institutional Capacity). A complete model specification following the ODD+D (Overview, Design concepts, Details, and Decision) protocol is included in the documentation.

This model is a minimal agent-based model (ABM) of green consumption and market tipping dynamics in a stylised two-firm economy. It is designed as an existence proof to illustrate how weak individual preferences, when combined with habit formation, social influence, and firm price adaptation, can generate non-linear transitions (tipping points) in market outcomes.

The economy consists of:
1) Two firms, each supplying a differentiated consumption bundle that differs in its fixed green share (one relatively greener, one less green).
2) Many households, each consuming a unit mass per period and allocating consumption between the two firms.

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In his 2003 book, Historical Dynamics (ch. 4), Turchin describes and briefly analyzes a spatial ABM of his metaethnic frontier theory, which is essentially a formalization of a theory by Ibn Khaldun in the 14th century. In the model, polities compete with neighboring polities and can absorb them into an empire. Groups possess “asabiya”, a measure of social solidarity and a sense of shared purpose. Regions that share borders with other groups will have increased asabiya do to salient us vs. them competition. High asabiya enhances the ability to grow, work together, and hence wage war on neighboring groups and assimilate them into an empire. The larger the frontier, the higher the empire’s asabiya.
As an empire expands, (1) increased access to resources drives further growth; (2) internal conflict decreases asabiya among those who live far from the frontier; and (3) expanded size of the frontier decreases ability to wage war along all frontiers. When an empire’s asabiya decreases too much, it collapses.  Another group with more compelling asabiya eventually helps establish a new empire.

Project Selene ABM Suite

Agent-Based Scenario Exploration for Consortium Cooperation Dynamics

Version: 2.1 (Revised)
Date: January 2026
Status: Exploratory Analysis Tool

HUMLAND Fire-in-the-Hole is a conceptual agent-based model (ABM) designed to explore the ecological and behavioral consequences of fire-driven hunting strategies employed by hunter-gatherers, specifically Neanderthals, during the Last Interglacial period around the Neumark-Nord (Germany) archaeological site.

This model builds on and specializes the HUMLAND 1.0.0 model (Nikulina et al. 2024), integrating anthropogenic fires, elephant group behavior, and landscape response to simulate interactions between humans, megafauna, and vegetation over time.