arXiv subjects

Diego Ortega

Publications and source records attributed to Diego Ortega.

5 recordsLinked to original sources

arXiv2025

Exploring the interplay between population profile and optimal routes in U.S. cities

Cities have developed over time alongside advancements in civilization, focusing on efficient travel and reducing costs. Many studies have examined the distinctive features of urban road networks, such as their length, efficiency, connection to population density, and other properties. However, the relationship between car routes and population in city structures remains unclear. In this study, we used the center of mass for each city tract, defined by the US Census, as the origins and destinations for our itineraries. We calculated travel time, and both Euclidean and travel distances for sixty major cities. We discovered that the total sum of all routes adheres to an urban law. The distribution of these car journeys follows Weibull functions, suggesting that the urban center plays a crucial role in optimizing routes across multiple cities. We also developed a simple point pattern model for the population, which aligns with the well-known decreasing exponential density expression. Our findings show that the interplay between population and path optimization influences city structure through its center. This study offers a new perspective on the fundamental principles that shape urban design.

physics.soc-ph↗

arXiv2022

Segregation in spatially structured cities

Half of the world population resides in cities and urban segregation is becoming a global issue. One of the best known attempts to understand it is the Schelling model, which considers two types of agents that relocate whenever a transfer rule depending on the neighbor distribution is verified. The main aim of the present study is to broaden our understanding of segregated neighborhoods in the city, i.e. ghettos, extending the Schelling model to consider economic aspects and their spatial distribution. To this end we have considered a monetary gap between the two social groups and five types of urban structures, defined by the house pricing city map. The results show that ghetto sizes tend to follow a power law distribution in all the considered cases. For each city framework the interplay between economical aspects and the geometrical features determine the location where ghettos reach their maximum size. The system first steps shape greatly the city's final appearance. Moreover, the segregated population ratios depends largely on the monetary gap and not on the city type, implying that ghettos are able to adapt to different urban frameworks.

physics.soc-ph↗

arXiv2022

A Schelling Extended Model in Networks -- Characterization of Ghettos in Washington D.C

Segregation affects millions of urban dwellers. The main expression of this reality is the creation of ghettos which are city parts characterized by a combination of features: low income, poor cultural level... Segregation models have been usually defined over regular lattices. However, in recent years, the focus has shifted from these unrealistic frameworks to other environments defined via geographic information systems (GIS) or networks. Nevertheless, each one of them has its drawbacks: GIS demands high-resolution data, that are not always available, and networks tend to have limited real-world applications. Our work tries to fill the gap between them. First, we use some basic GIS information to define the network, and then, run an extended Schelling model on it. As a result, we obtain the location of ghettos. After that, we analyze which parts of the city are segregated, via spatial analysis and machine learning and compare our results. For the case study of Washington D.C., we obtain an $80\%$ accuracy.

physics.soc-ph↗

arXiv2021

A Schelling model with a variable treshold in a closed city segregation model. Analysis of the universality classes

Residential segregation is analyzed via the Schelling model, in which two types of agents attempt to optimize their situation according to certain preferences and tolerance levels. Several variants of this work are focused on urban or social aspects. Whereas these models consider fixed values for wealth or tolerance, here we consider how sudden changes in the tolerance level affect the urban structure in the closed city model. In this framework, when tolerance decreases continuously, the change rate is a key parameter for the final state reached by the system. On the other hand, sudden drops in tolerance tend to group agents into clusters whose boundary can be characterized using tools from kinetic roughening. This frontier can be categorized into the Edward-Wilkinson (EW) universality class. Likewise, the understanding of these processes and how society adapts to tolerance variations are of the utmost importance in a world where migratory movements and pro-segregational attitudes are commonplace.

physics.soc-ph↗

arXiv2021

Avalanches in an extended Schelling model: an explanation of urban gentrification

In this work we characterize sudden increases in the land price of certain urban areas, a phenomenon causing gentrification, via an extended Schelling model. An initial price rise forces some of the disadvantaged inhabitants out of the area, creating vacancies which other groups find economically attractive. Intolerance issues forces further displacements, possibly giving rise to an avalanche. We consider how gradual changes in the economic environment affect the urban architecture through such avalanche processes, when agents may enter or leave the city freely. The avalanches are characterized by power-law histograms, as it is usually the case in self-organized critical phenomena.

physics.soc-ph↗