Complex system designed to simulate and analyze various urban scenarios

The OLYMPUS model (Elessa Etuman et al., 2018) integrates several interacting subsystems that represent the various aspects of the urban issue, including demography, networks, mobility, energy demand of buildings, and production of polluting emissions. The architecture of the model is based on the statistical analysis of individual behaviors regarding energy consumption within a defined geographical area. This model allows me to understand, at the individual level, the repercussions of urban planning and the organization of public transport systems on movements, energy consumption and, consequently, on the emissions of greenhouse gases and pollutants into the atmosphere. As essential input data, OLYMPUS requires variables influencing urban configuration - notably the spatial structure of the city, demographic density, employment centers, and transport infrastructures - as well as information from surveys on mobility habits, household equipment (for example, vehicles and heating systems), and the specific energy composition of the region. The simulation process of the OLYMPUS model encompasses the entire population of the studied area by adopting statistical methods to develop a synthetic population with attributes similar to those of the real population. This development relies on the use of conditional probabilities to assign individual characteristics such as age, gender, and socioeconomic status, integrating data such as possession of a driver's license, based on information concerning land use and sociodemographic data. The model generates for this fictitious population travel profiles and behaviors based on demographic data and the urban landscape, where the mobility of each subject is simulated through (1) an activity-based modeling for the creation of mobility demand, (2) a gravity method for the spatial distribution of activities, and (3) the allocation of transport demand on the network through a shortest path method, considering network congestion.

In parallel, the energy demand of buildings in the area is calculated based on standard energy consumption rates for households and businesses, taking into account domestic practices and building specifics, including variables such as housing type, area, and energy consumption habits, adjusted according to the climate. OLYMPUS also classifies areas according to three main criteria: urban density, attractiveness, and accessibility of urban spatial units. It establishes connections between these dimensions by calculating transport demand, derived from a register of daily activities, which results in the production of matrices and mobility patterns for each individual in the studied space. Finally, pollutant emissions are assessed by applying methodologies based on activity data, taking into account the characteristics of equipment (type of vehicles and heating devices), the distribution of fuel types, and the regional energy composition. OLYMPUS produces emission data designed to feed air quality models.