Mega cities and some large cities have been trying to alleviate serious problems such as traffic congestion, shortage of public services, and environmental pressure by reducing population. Conversely, some cities are facing challenges such as population loss and low density, need to address issues such as inefficient land use, low spatial efficiency, and lack of social vitality. The high concentration of urban population and the density collapse are two sides of spatial imbalance, reflecting the deviation of individual rationality from collective rationality. In this regard, game theory can be used to analyze its practical logic, with a focus on the agglomeration dimension. Research has found that individual rational choices in urban systems make large cities even larger and locked in; In the core-periphery game, the competition to save total commuting distance leads to an overly dense core, while functional duality limits the probability of migration; At the community scale, both medium and high density constitute Nash Equilibrium, but it depends on spatial supply. Therefore, population diversion should be based on individual preferences, and guide the rational allocation of population density by reconstructing the income matrix.

With the continuous deepening of urbanization, urban density has obviously become an important factor affecting the sustainable development of cities, as well as its connotation has been contained in the huge and complex urban system and presents characteristics of multiple values. Firstly, this paper extracts elements related to urban density from the theoretical models of “Compact City”, “New Urbanism” and “Smart Growth”, and clarifies design strategies for addressing the development of high-density compact urban areas. Secondly, through analyzing typical cases, this paper aims to address cognitive misconceptions regarding spatial design in compact urban areas and explore the value of spatial design governance. Results show that high compactness in spatial design governance is characterized by three main manifestations: three-dimensional physical space with functional integration, spatial environment quality and experiential value, and spatial matching degree of resource elements. Finally, taking Shenzhen as a practical case study, this paper proposes innovative approaches to existing design methodologies from three aspects: achieving balanced density allocation, enhancing ecological aspects of density through precise increments, and creating spatial quality within dense environments. This paper provides a reference for the method innovation and practice strategy of spatial design in compact urban areas, so as to establish a spatial design technology module for high-quality development and high-quality life.

Existed research has revealed that urban density would influence the incidence rates of common chronic diseases, but lack theoretical mechanism and empirical studies. The development of artificial intelligence (AI) and the urban big data provide new opportunities to explore original ideas and methods of complex correlations. Aiming at identifying the relationships between urban density and chronic diseases, this paper takes metropolitan census tracts in U.S. as the study areas and analyzes three dimensions of population density, built environment density, and activity density. With the help of data visualization, this paper initially investigates the trends between variables. By building several machine learning (ML) models and using interpretable methods, this paper then uncovers the key influencing features, describes non-linear relationships, finds key thresholds, explains the interactions of factors, and discovers spatial distinction. Finally, this paper summarizes similarities and differences of common chronic diseases. The results verify the significant impacts of urban density on chronic diseases, interpret the complicated relationships and regional disparity. The conclusions are of great importance for constructing health cities, guiding sustainable development, and promoting livability.

Garden City is the most influential urban planning idea in the 20th century, as well as one of the earliest foreign planning ideas introduced into China with deep influence. Using Said’s traveling theory, based on the perspective of China’s subject, this paper analyzes the complicated process and comprehensive impacts of Garden City since entering China. Over the past hundred years, the travel of Graden City in China could be divided into three phases: (1) “misreading and remoulding”from the early 20th century to the 1940s; (2) “criticism and rejection”from the 1950s to the 1970s; and (3) “re-reading and re-creation” after the 1980s. China’s acceptance, rejection and remoulding of Garden City mainly according to the characteristics of Chinese ideological culture and the internal demands of urban development in different periods. Garden City is remolded and utilized according to China’s conditions, and finally internalized into a part of Chinese idea and practice. Entering the new era, Park City is hoping to replace Garden City with a new journey.

Tel Aviv is the first modern Hebrew city in the world, which has significant values for the international urban planning history study. As the only implemented urban planning scheme made by British planner Patrick Geddes, and the key factor that Tel Aviv “White City” was listed as a World Heritage Site, the Geddes Plan of Tel Aviv in the early 20 century is worthy of research. This paper outlines the process of Tel Aviv’s early modern planning history, discusses the contents and innovative ideas of Geddes Plan from three aspects: regional research and urban orientation, land division and general layout, road system and block planning. On this basis, the paper further analyzes the unique connotations of Geddes Plan. It finds that continuation and innovation are not distinct opposing concepts, which can be integrated into the urban planning scheme; Geddes is not only the successor of Tel Aviv’s previous urban planning, but also a great pioneer of modernist urban planning. The paper indicates that tracing back to the essence of Geddes Plan is still has positive references value for today’s urban planning practice.

As population continues to agglomerate in cities, high density has emerged as a prominent feature of large cities, accompanied by growing concerns regarding urban health issues. While problems such as traffic congestion, residential overcrowding, and environmental degradation are exacerbated in high-density cities, the compact urban layout and well-developed public transportation can also contribute to reduced energy consumption and increased physical activity levels among residents. These dual impacts are interconnected. Therefore, how to allocate built environment elements through urban planning and design to improve residents’ overall health while mitigating the negative effects of density has become a critical issue for urban health development. This paper proposes a design concept in holistic health and explore it through a case study involving multi-source data from four typical high-density cities: New York, Paris, Hong Kong, and Shanghai. Based on the basic behavioral activities in cities, the study identifies different dimensions of the built environment that are crucial for health and quantitatively analyzes the influence of high-density built environments on urban health. Ultimately, it summarizes the demands of urban planning and design for holistic health and explores strategies for designing highdensity built environments with the overarching goal of promoting holistic health.

With the frequent disasters caused by climate change, the construction of resilient cities has become an important measure to deal with risks. As the fundamental unit of governance, community resilience system construction is particularly important. Nature-based solutions (NbS) is an important path to achieve community resilience, primarily through integrating engineering interventions and systematic social governance measures to effectively enhance both the material and social resilience of communities. The United States has made great achievements in applying NbS to improve community resilience. This paper explores the mechanisms of NbS in community resilience construction, reviews the process of integrating NbS into community resilience planning in the United States, and categorizes typical examples based on the mechanisms. Finally, this paper draws insights from the United States experiences from theoretical, planning, and governance perspectives, aiming to provide references for the development of resilient communities in China.