Hasil untuk "Urbanization. City and country"

Matthew Fry, Rylee Babino, Ashley R. Coles et al.

Abstract Digital tools are used widely to plan and manage urban forests for sustainability. We conducted a scoping review to investigate how researchers use and envision integrating digital tools into urban forestry. Employing content analysis, we identified and analyzed which urban forest variables are studied, how decision-making is understood, and who this research empowers. Findings indicate that researchers predominantly use remote sensing tools to inventory and assess urban forests; tools are less often used in strategizing, monitoring, or planning for future scenarios. Researchers recognize municipal governments as loci of urban forestry decision-making, yet fail to identify entities capable of implementing findings. References to inclusive and participatory governance are infrequent. We find that reliance on a limited set of digital tools predetermines which aspects of urban forests are valued and whose perspectives are privileged. Additional emphasis on digital tools activating participation in urban forestry is needed to enhance urban forest sustainability.

Mingxuan Liu, Honglin He, Elisa Ricci et al.

Urban embodied AI agents, ranging from delivery robots to quadrupeds, are increasingly populating our cities, navigating chaotic streets to provide last-mile connectivity. Training such agents requires diverse, high-fidelity urban environments to scale, yet existing human-crafted or procedurally generated simulation scenes either lack scalability or fail to capture real-world complexity. We introduce UrbanVerse, a data-driven real-to-sim system that converts crowd-sourced city-tour videos into physics-aware, interactive simulation scenes. UrbanVerse consists of: (i) UrbanVerse-100K, a repository of 100k+ annotated urban 3D assets with semantic and physical attributes, and (ii) UrbanVerse-Gen, an automatic pipeline that extracts scene layouts from video and instantiates metric-scale 3D simulations using retrieved assets. Running in IsaacSim, UrbanVerse offers 160 high-quality constructed scenes from 24 countries, along with a curated benchmark of 10 artist-designed test scenes. Experiments show that UrbanVerse scenes preserve real-world semantics and layouts, achieving human-evaluated realism comparable to manually crafted scenes. In urban navigation, policies trained in UrbanVerse exhibit scaling power laws and strong generalization, improving success by +6.3% in simulation and +30.1% in zero-shot sim-to-real transfer comparing to prior methods, accomplishing a 300 m real-world mission with only two interventions.

Yatao Zhang, Ye Hong, Song Gao et al.

Understanding how urban systems and traffic dynamics co-evolve is crucial for advancing sustainable and resilient cities. However, their bidirectional causal relationships remain underexplored due to challenges of simultaneously inferring spatial heterogeneity, temporal variation, and feedback mechanisms. To address this gap, we propose a novel spatio-temporal causality framework that bridges correlation and causation by integrating spatio-temporal weighted regression with a newly developed spatio-temporal convergent cross-mapping approach. Characterizing cities through urban structure, form, and function, the framework uncovers bidirectional causal patterns between urban systems and traffic dynamics across 30 cities on six continents. Our findings reveal asymmetric bidirectional causality, with urban systems exerting stronger influences on traffic dynamics than the reverse in most cities. Urban form and function shape mobility more profoundly than structure, even though structure often exhibits higher correlations, as observed in cities such as Singapore, New Delhi, London, Chicago, and Moscow. This does not preclude the reversed causal direction, whereby long-established mobility patterns can also reshape the built environment over time. Finally, we identify three distinct causal archetypes: tightly coupled, pattern-heterogeneous, and workday-attenuated, which map pathways from causal diagnosis to intervention. This typology supports city-to-city learning and lays a foundation for context-sensitive strategies in sustainable urban and transport planning.

Ricardo de S Alencar, Fabiano L. Ribeiro, Horacio Samaniego et al.

\abstract{Urban scaling theories posit that larger cities exhibit disproportionately higher levels of socioeconomic activity and human interactions. Yet, evidence from developing contexts (especially those marked by stark socioeconomic disparities) remains limited. To address this gap, we analyse a month-long dataset of 3.1~billion voice-call records from Brazil's 100 most populous cities, providing a continental-scale test of urban scaling laws. We measure interactions using two complementary proxies: the number of phone-based contacts (voice-call degrees) and the number of trips inferred from consecutive calls in distinct locations. Our findings reveal clear superlinear relationships in both metrics, indicating that larger urban centres exhibit intensified remote communication and physical mobility. We further observe that gross domestic product (GDP) also scales superlinearly with population, consistent with broader claims that economic output grows faster than city size. Conversely, the number of antennas required per user scales sublinearly, suggesting economies of scale in telecommunications infrastructure. Although the dataset covers a single provider, its widespread coverage in major cities supports the robustness of the results. We nonetheless discuss potential biases, including city-specific marketing campaigns and predominantly prepaid users, as well as the open question of whether higher interaction drives wealth or vice versa. Overall, this study enriches our understanding of urban scaling, emphasising how communication and mobility jointly shape the socioeconomic landscapes of rapidly growing cities.

Ariel Favier, Christine Hedde-von Westernhagen, Meghan Krieg et al.

More than half of the world's population now lives in urban environments, which concentrate services and infrastructure to satisfy the material needs of a growing number of inhabitants. The interdependencies between physical infrastructure systems are required for cities to function efficiently, but simultaneously expose cities to new hazards. Failures that emerge from one infrastructure system and cascade through these interdependencies are becoming larger and more frequent due to climate change and growing urban environments. Because of the uneven distribution of resources and basic services, cascade failures often exacerbate pre-existing socioeconomic inequalities. Human communities rely on both social capital and infrastructure services to prepare for, manage, and recover from these challenging scenarios, but the overlap between social and physical infrastructure creates unpredictable feedback dynamics. While prior research has focused on either social capital or physical infrastructure in urban disaster management, an integrative view of these two perspectives is seldom explored. In this paper, the feedback mechanisms between the physical and social layers of different urban designs are identified and analyzed to optimize relief response. Methodologically, we identify cities with high accessibility that have undergone disasters. From these cities, we measure their physical and social resilience indicators before and after disaster as a means to evaluate the impact of accessibility on disaster relief and preparedness. We will supplement this empirical analysis with a simulation that captures a cascade failure/disaster through a multilayer infrastructure and social network model.

Gaëtan Laziou, Rémi Lemoy

A good understanding of cities is crucial to implement urban planning policies leading to social and economic sustainability and an efficient use of resources. While urban concentration has been associated with both positive and negative effects, echoing debates on compact cities, few studies have documented how density evolves with city size. We fill this gap by investigating how the population density radial structure changes across the urban hierarchy. Our results uncover strong regularities in urban settlements. In terms of density, cities can be seen as exponential cones which evolve homothetically with city population. This rather simple but universal geometric structure of cities provides a new spatial scaling law, which is an important step forward in understanding how cities work and grow. Some deviations can be observed, which mainly oppose dense cities in the developing world and sprawled cities in high-income countries, associated with high energy use per capita. This suggests that urban lifestyle in wealthiest countries has come at the price of negative impacts on environmental outcomes. This research has a broad range of applications as it provides a powerful tool to compare cities of different sizes.

Yu Shang, Yuming Lin, Yu Zheng et al.

Cities, as the essential environment of human life, encompass diverse physical elements such as buildings, roads and vegetation, which continuously interact with dynamic entities like people and vehicles. Crafting realistic, interactive 3D urban environments is essential for nurturing AGI systems and constructing AI agents capable of perceiving, decision-making, and acting like humans in real-world environments. However, creating high-fidelity 3D urban environments usually entails extensive manual labor from designers, involving intricate detailing and representation of complex urban elements. Therefore, accomplishing this automatically remains a longstanding challenge. Toward this problem, we propose UrbanWorld, the first generative urban world model that can automatically create a customized, realistic and interactive 3D urban world with flexible control conditions. UrbanWorld incorporates four key stages in the generation pipeline: flexible 3D layout generation from OSM data or urban layout with semantic and height maps, urban scene design with Urban MLLM, controllable urban asset rendering via progressive 3D diffusion, and MLLM-assisted scene refinement. We conduct extensive quantitative analysis on five visual metrics, demonstrating that UrbanWorld achieves SOTA generation realism. Next, we provide qualitative results about the controllable generation capabilities of UrbanWorld using both textual and image-based prompts. Lastly, we verify the interactive nature of these environments by showcasing the agent perception and navigation within the created environments. We contribute UrbanWorld as an open-source tool available at https://github.com/Urban-World/UrbanWorld.

Margarita Mishina, Mingyi He, Venu Garikapati et al.

Urban development is shaped by historical, geographical, and economic factors, presenting challenges for planners in understanding urban form. This study models commute flows across multiple U.S. cities, uncovering consistent patterns in urban population distributions and commuting behaviors. By embedding urban locations to reflect mobility networks, we observe that population distributions across redefined urban spaces tend to approximate log-normal distributions, in contrast to the often irregular distributions found in geographical space. This divergence suggests that natural and historical constraints shape spatial population patterns, while, under ideal conditions, urban organization may naturally align with log-normal distribution. A theoretical model using preferential attachment and random walks supports the emergence of this distribution in urban settings. These findings reveal a fundamental organizing principle in urban systems that, while not always visible geographically, consistently governs population flows and distributions. This insight into the underlying urban structure can inform planners seeking to design efficient, resilient cities.

Vinicius M. Netto, Otavio Peres, Caio Cacholas

Entropy is arguably one of the most powerful concepts to understand the world, from the behavior of molecules to the expansion of the universe, from how life emerges to how hybrid complex systems like cities come into being and continue existing. Yet, despite its widespread application, it is also one of the most misunderstood concepts across the sciences. This chapter seeks to demystify entropy and its main interpretations, along with some of its explorations in the context of cities. It first establishes the foundations of the concept by describing its trajectory since its inception in thermodynamics and statistical mechanics in the 19th century, its different incarnations from Boltzmanns pioneering formulation and Shannons information theory to its absorption in biology and the social sciences, until it reaches a nascent urban science in the 1960s. The chapter then identifies some of the main domains in which entropy has been explored to understand cities as complex systems, from entropy-maximizing models of spatial interaction and applications as a measure of urban form, diversity, and complexity to a tool for understanding conditions of self-organization and urban sustainability.

Zeng Guanwen, Serok Nimrod, Lieberthal Efrat Blumenfeld et al.

We analyze the patterns of traffic jams in urban networks of five large cities and an urban agglomeration region in China using real data based on a recently developed jam tree model. This model focuses on the way traffic jams spread through a network of streets, where the first street that becomes congested represents the bottleneck of the jam. We extended the model by integrating additional realistic jam components into the model and find that, while the locations of traffic jams can vary significantly from day to day and hour to hour, the daily distribution of the costs associated with these jams follows a consistent pattern, i.e., a power law with similar exponents. This distribution pattern appears to hold not only for a given region on different days, but also for the same hours on different days. This daily pattern of exponent values for traffic jams can be used as a fingerprint for urban traffic, i.e., jam-prints. Our findings are useful for quantifying the reliability of urban traffic system, and for improving traffic management and control.

Heba Mohamed Ammar, Kariman Ahmed Shawkyorcid

تتسم المدن بالتغير المستمر بشكل تكيفي لتتجاوز الأزمات الطبيعية والمجتمعية التي تواجهها، يتم هذا التغير والتطور باستحداث آليات متنوعة لمواكبة التغير المستمر. وشهدت مصر سلسلة من التغيرات والتحديات الاقتصادية الاجتماعية، ومن أحدث ما واجهته مصر والعالم جائحة فيروس كورونا المستجد (كوفيد-19). وتعد المجتمعات ذات الدخل المنخفض الأكثر تأثراً بالأزمات والتغيرات والأقل قدره على معالجة التغيرات والتكيف معها، ووفقاً لتقديرات البنك الدولي لعام 2020 بلغت نسبة السكان ذوي الدخل المنخفض بمصر نحو 26.1%. تعتمد زيادة قدرة المجتمعات وخاصة ذات الدخل المنخفض على التكيف ومواجهة الأزمات على أسباب متعددة، أحد أهمها مدى فعالية منظومة ادارة العمران. وتساهم الحوكمة التكيفية في تمكين المجتمعات المحلية للتصدي للأزمات سواء المحلية أو العالمية، وفي تحقيق المرونة وتعزيز قدرة المجتمع على التكيف بفاعلية مع المتغيرات المختلفة. لذا يهدف البحث للتوصل لكيفية دمج أبعاد الحوكمة التكيفية بمنظومة إدارة العمران بمؤسسات التنمية العمرانية بمصر خاصة لمشروعات تنمية المجتمعات ذات الدخل المنخفض. وتحديد أوجه القوة التي تساهم في إمكانية تطبيقها وأوجه القصور الواجب مراعاتها وتحسينها. للوصول لذلك الهدف يقوم البحث بالتعرف على مفهوم الحوكمة التكيفية وأبعادها والنماذج النظرية المتعلقة بها بالمراجعة التحليلية للدراسات النظرية، بالإضافة إلى تحليل نماذج من التجارب العالمية المطبقة لمعايير الحوكمة التكيفية، لتحديد مدى امكانية تطبيق تلك المعايير بمؤسسات التنمية العمرانية بمصر، كما تم اجراء استبيان للخبراء بمجال التخطيط العمراني وإدارة العمران لتحديد أولويات تطبيق معايير الحوكمة التكيفية بالسياق المصري. وتتلخص نتائج البحث في الوصول لإطار لتطبيق الحوكمة التكيفية بمؤسسات التنمية العمرانية بمصر، والذي قد يساهم في تحسين أوضاع المجتمعات ذات الدخل المنخفض لتكون اكثر مرونة وقدرة على التكيف والصمود ضمن الإطار المؤسسي لإدارة العمران بمصر. Cities are constantly adapting to deal with the natural and societal crises they are experiencing. This adaptation requires developing various mechanisms to keep pace with ongoing changes. Egypt has experienced a range of social and economic changes and challenges. (COVID-19) is the most recent crisis in Egypt and the whole world. Low-income communities are the most affected by crises and changes while being the least able to adapt to them, furthermore, Egypt's low-income population was about 26.1% according to the World Bank estimation for 2020. Achieving more resilient communities, particularly low-income, is dependent on multiple factors. The efficiency of the urban management system is one of the most crucial factors, Adaptive governance empowers communities to respond to both local and global crises, increases resilience, and enhances society's ability to adapt to changing factors. The research aims to examine how to integrate the adaptive governance aspects in the management system of Egyptian urban development institutions, especially for low-income community development projects. In addition, identify the strengths and weaknesses of applying adaptive governance. Based on the analytical theoretical approach the research reviews literature of adaptive governance definition, aspects, and theoretical models. International case studies have been selected and analyzed to determine the applicability of adaptive governance indicators to Egyptian urban development institutions. In addition, an expert questionnaire was conducted as an empirical study, to examine ranking of the adaptive governance indicators according to priority in the Egyptian context. The paper ends with a framework for adaptive governance application in the Egyptian urban development institutions. Which could be applied and enhanced the resilience of the low-income communities.

Christopher M. Raymond, Alex M. Lechner, Minttu Havu et al.

Abstract Managing nature-based solutions (NBS) in urban areas for carbon mitigation and biodiversity outcomes is a global policy challenge, yet little is known about how to both assess and weave diverse knowledge systems and values into carbon-biodiversity trade-off assessments. This paper examines the spatial relationships between biophysical and social values for carbon sequestration potential (measured as carbon dioxide, CO2, flux) and biodiversity in Helsinki, Finland, using integrated valuation. The approach combines methods from carbon sequestration modelling, expert scoring approaches to biodiversity assessment and public participation geographic information systems (PPGIS). Results indicate strong spatial associations between biophysical assessment of CO2 flux and biodiversity priorities, and weaker associations between biophysical and social values. Integration of social and biophysical values leads to multiple pathways for protection of NBS to achieve carbon mitigation and biodiversity outcomes, as well as options for the spatial targeting of education and capacity building programs to areas of local concern.

Rosário Mauritti, Sónia Pintassilgo, Helena Belchior Rocha et al.

O estudo analisa o posicionamento de Portugal nos fluxos de mobilidade internacional por motivos de estudo, num processo que se constrói e consolida, sobretudo, no âmbito dos acordos de cooperação da CPLP. O objetivo é identificar os perfis e características dos estudantes estrangeiros que frequentam o ensino superior em Portugal, sobretudo os provenientes de países da CPLP, detalhar os fluxos e as proveniências, bem como a sua distribuição pelas instituições de ensino superior e pelo território nacional, discutindo os potenciais benefícios da sua integração para as diferentes tipologias de instituições/territórios. O estudo recorre a dados oficiais de natureza censitária produzidos pela DGEEC, relativos a 2012-2021. A análise demonstra a presença crescente de estudantes internacionais nas IES portuguesas, num processo facilitado pela alteração do quadro institucional no âmbito dos acordos de cooperação. No elenco de razões para a adesão das IES a essa tendência, assinalam-se quer as possibilidades de captação de novos recursos financeiros através das prestações de propinas, quer elementos simbólicos de prestígio das IES nos rankings nacionais e internacionais, além do potencial de dinamismo e inovação que resulta da confluência no campus das IES de estudantes com referenciais de experiência e orientações culturais diferenciadas. No artigo evidencia-se também a relevância da procura internacional para o reforço da oferta de ensino superior hoje em funcionamento nas diferentes áreas de educação e ciclos de estudo, incluindo nas regiões com menor capacidade de atração de estudantes nacionais.The study analyses the positioning of Portugal in the international mobility flows for study purposes, in a process built and consolidated mainly in the scope of the CPLP cooperation agreements. The aim is to identify the profile and characteristics of foreign students attending higher education in Portugal, especially those coming from CPLP countries, to detail the flows and origins, as well as their distribution across higher education institutions and the national territory, discussing the potential benefits of their integration for the different types of institutions/territories. The study is based on official census data produced by DGEEC for the years 2012-2021. The analysis shows the adherence of Portuguese Higher Education Institutions (HEI) to the recruitment of international students, a process facilitated by the change in the institutional framework under the cooperation agreements. In the list of reasons for this adhesion, it is pointed out both the possibilities of attracting new financial resources through the payment of tuition fees, as well as symbolic elements of prestige of the HEI in the national and international rankings, besides the potential for dynamism and innovation that results from the confluence on the HEI campus of students with differentiated references of experience and cultural orientations. The article also highlights the relevance of international demand to strengthen the supply of higher education currently in operation in the different areas of education and study cycles, including in regions with less capacity to attract national students.

Shih-Kung Lai

Nora Fagerholm, Karl Samuelsson, Salla Eilola et al.

Abstract Recent empirical research has confirmed the importance of green infrastructure and outdoor recreation to urban people’s well-being during the COVID-19 pandemic. However, only a few studies provide cross-city analyses. We analyse outdoor recreation behaviour across four Nordic cities ranging from metropolitan areas to a middle-sized city. We collected map-based survey data from residents (n = 469–4992) in spring 2020 and spatially analyse green infrastructure near mapped outdoor recreation sites and respondents’ places of residence. Our statistical examination reveals how the interplay among access to green infrastructure across cities and at respondents’ residential location, together with respondents’ socio-demographic profiles and lockdown policies or pandemic restrictions, affects outdoor recreation behaviour. The results highlight that for pandemic resilience, the history of Nordic spatial planning is important. To support well-being in exceptional situations as well as in the long term, green infrastructure planning should prioritise nature wedges in and close to cities and support small-scale green infrastructure.

Haruka Kato, Atsushi Takizawa

Abstract Controlling human mobility is thought to be an effective measure to prevent the spread of the COVID-19 pandemic. This study aims to clarify the human mobility types that impacted the number of COVID-19 cases during the medium-term COVID-19 pandemic in the Osaka metropolitan area. The method used in this study was analysis of the statistical relationship between human mobility changes and the total number of COVID-19 cases after two weeks. In conclusion, the results indicate that it is essential to control the human mobility of groceries/pharmacies to between −5 and 5% and that of parks to more than −20%. The most significant finding for urban sustainability is that urban transit was not found to be a source of infection. Hence governments in cities around the world may be able to encourage communities to return to transit mobility, if they are able to follow the kind of hygiene processes conducted in Osaka.

Katielle Silva, Jorge Malheiros

Entre 2010 e 2015, o contexto migratório português alterou-se significativamente em consequência dos impactos sociais da crise financeira e económica, o que resultou num saldo migratório negativo, combinando redução do fluxo de entrada e incremento nas saídas de imigrantes (para novos destinos ou retorno ao país de origem) com o aumento da emigração portuguesa. Neste contexto, alguns casais luso-brasileiros mudaram-se para o Brasil, onde as oportunidades económicas e sociais, naquele período, pareciam mais favoráveis; contudo, entre 2016 e 2019, esse fluxo terá de novo oscilado, favorecendo agora Portugal enquanto espaço de destino. Combinando dados quantitativos sobre casamentos e nascimentos para demonstrar as ligações familiares entre brasileiras/os e portugueses/as e dados qualitativos coletados em entrevistas com famílias luso-brasileiras que vieram para Portugal, este texto procurou escrutinar duas ideias principais: (i) as razões do retorno para Portugal e a relevância dos contextos familiares, neste processo; e (ii) os projetos migratórios futuros e as suas implicações na (im)permanência neste país europeu. Teoricamente este artigo pretende desafiar e discutir categorias migratórias clássicas dos estudos migratórios como emigrantes-imigrantes e, sobretudo, partida e retorno, posicionando-as em contextos binacionais. Pretende-se assim desafiar a noção clássica de retorno a partir de uma perspetiva centrada em sujeitos migrantes mais complexos (os casais mistos) em relação aos espaços originais de referência que, por sua vez, também se vão transformando no quadro da circularidade migratória.

Lucía Fank

<p>There are multiple disadvantages associated with urban informality that negatively affect inhabitants living conditions, leading to numerous vulnerability situations. This research aims to define urban vulnerability degree and composition in informal settlements of Ushuaia, Argentina, from a comparative and multi-actor approach. For this, an index is applied to incorporate existing problems comprehensiveness, weighted according to three groups of actors: neighborhood referents, local government and the specialized academy. Results show that urban vulnerability level is higher in new settlements than in the rest of the city, and that its composition varies according to the case and the perspective of the different actors. The analysis presented constitutes a basic input for adequate and comprehensive public policies formulation to deal with urban informality, allowing to establish prioritization criteria establishment in future territorial approaches.</p>

Martin Feldkircher, Florian Huber, Gary Koop et al.

Panel Vector Autoregressions (PVARs) are a popular tool for analyzing multi-country datasets. However, the number of estimated parameters can be enormous, leading to computational and statistical issues. In this paper, we develop fast Bayesian methods for estimating PVARs using integrated rotated Gaussian approximations. We exploit the fact that domestic information is often more important than international information and group the coefficients accordingly. Fast approximations are used to estimate the latter while the former are estimated with precision using Markov chain Monte Carlo techniques. We illustrate, using a huge model of the world economy, that it produces competitive forecasts quickly.

Thomas G. Beatty

Next-generation missions designed to detect biosignatures on exoplanets will also be capable of placing constraints on technosignatures (evidence for technological life) on these same worlds. Here, I estimate the detectability of nightside city lights on habitable, Earth-like, exoplanets around nearby stars using direct-imaging observations from the proposed LUVOIR and HabEx observatories, assuming these lights come from high-pressure sodium lamps. I consider how the detectability scales with urbanization fraction: from Earth's value of 0.05%, up to the limiting case of an ecumenopolis -- or planet-wide city. Though an Earth analog would not be detectable by LUVOIR or HabEx, planets around M-dwarfs close to the Sun would show detectable signals at $3\,σ$ from city lights, using 300 hours of observing time, for urbanization levels of 0.4% to 3%, while city lights on planets around nearby Sun-like stars would be detectable at urbanization levels of $\gtrsim10\%$. The known planet Proxima b is a particularly compelling target for LUVOIR A observations, which would be able to detect city lights twelve times that of Earth in 300 hours, an urbanization level that is expected to occur on Earth around the mid-22nd-century. An ecumenopolis, or planet-wide city, would be detectable around roughly 30 to 50 nearby stars by both LUVOIR and HabEx, and a survey of these systems would place a $1\,σ$ upper limit of $\lesssim2\%$ to $\lesssim4\%$, and a $3\,σ$ upper limit $\lesssim10\%$ to $\lesssim15\%$, on the frequency of ecumenopolis planets in the Solar neighborhood assuming no detections.