The Survey
Image taken from the project "Renaissance Écologique", promoted by the French author and expert in ecology, Julien Dossier.
What is the purpose of the survey?
The survey you are asked to fill out will be used to:
Estimate individual awareness about climate change.
Georeference responses on the map of the historic center of Siena.
Define different types of behavior regarding sustainable practices on topics such as recycling, energy and water consumption, purchasing goods, and cleaning public spaces.
Data collection and agent's definition
An agent-based model that accurately represents reality and where entities are all the people living in the historic center of Siena, including those who reside temporarily in the city (students, tourists, workers, etc.), requires extensive data collection.
For this reason, we have developed a survey (available at this link: https://survey.unisi.it/MAS) aimed at obtaining individual opinions on climate change and environmental issues in various aspects such as recycling, care and cleaning of public spaces, energy and water consumption, food and goods purchasing, low-emission transportation, and renewable energy technologies for the home.
The responses to the survey are anonymous, except for the request to indicate the street of residence/accommodation (we do not ask for the house number), and will be managed in accordance with the European Regulation 2016/679 on data protection. The responses obtained do not investigate private aspects of citizens and will serve to identify different types of behavior according to individual inclinations and opinions towards sustainable practices, with the aim of having an overall picture of the community rather than analyzing the responses individually.
The street of residence (or accommodation, in the case of tourists and temporary visitors to the city) is solely used to georeference the responses and position them on the map of our historic center, so that the model represents the urban structure of our city as realistically as possible.
Georeferentiation of responses on the map of the historic center of Siena
The map with a black background shown in the figure represents the historic center of Siena. The red nodes represent an example of georeferencing of the agents.
How is the agent-based model built starting from the survey?
Once the dataset obtained from the survey has been analyzed, it will be used to develop the agent-based model (ABM).
Each agent in the model is an individual citizen, student, worker, tourist, or temporary visitor of the city who has responded to the survey and is represented by a node placed on the map of Siena.
The nodes are connected to each other to form a mathematical structure called a graph. The two questions in the survey asking for the residential address (or accommodation in the case of tourists and temporary visitors) and the most frequented street for work, study, sports, or other purposes serve mainly to build the graph on which the agent-based model is based.
The responses obtained from the survey define the initial state of the model, from which it is possible to simulate the global behavior of the community over time.
This is made possible by the fact that at each time step, each agent makes a decision based on its internal state (defined by the questionnaire responses) and interaction with others, where the interaction is represented by the graph on which the model is positioned.
The decisions concern issues that have an environmental impact, such as recycling and water and energy consumption.
From a mathematical point of view, the decision-making process is described by game theory, and more specifically, each agent can choose between two strategies at each time step: cooperate and defect, where cooperation represents environmentally sustainable actions and vice versa for defection.
The types of behavior identified through the questionnaire correspond to the types of games most studied and recognized in the literature according to game theory, including the Prisoner's Dilemma, the Stag-Hunt and the Hawk-Dove games.
More specifically, each agent in the model will be characterized by a particular behavior regarding sustainable practices: some may show strong active commitment, others may deny the importance of such practices, while others may be influenced by the actions of their neighbors or oppose them, and still others may simply act according to their individual interests.
Example of how the ABM model works
The two images show how the ABM works with 324 agents (colored nodes) placed on the map of Siena.
The first image represents the model configuration at the initial time, provided by the survey.
On the other hand, the second image represents the model configuration at the final time.
Once the simulation is started, after some time, the system reaches a global sustainability scenario, made visible by the fact that in the model, blue and red colors have been assigned to cooperation and defection, respectively.
Initial model configuration
Final model configuration
What will the model be used for?
The obtained agent-based model can be used:
to study measures to foster sustainable behaviors at the individual level, contributing to fight climate change
to develop and customize intervention strategies and adapt sustainable policies based on the specific needs of citizens.
We would like to thank Professors Pierangelo Isernia, Francesco Olmastroni and Simone Bastianoni for their valuable support in developing the survey.