The First Urban Systems Forum
On 19 July 2026, the Urban Systems Institute (USI) of the University of Hong Kong (HKU), in collaboration with the Institute for Climate and Carbon Neutrality (ICCN) at HKU, the State Key Laboratory of Subtropical Building and Urban Science Hong Kong Base (SKL-SBUS-HK), the Otto Poon Charitable Foundation Smart Cities Research Institute, The Hong Kong Polytechnic University, and the IEEE Geoscience and Remote Sensing Society Hong Kong Chapter (GRSS-HK), successfully hosted the inaugural Urban Systems Forum under the theme "Advanced Modeling of Urban Systems for Sustainable Cities." The Forum served as a high-level international academic platform, fulfilling USI's core mission to advance the sciences of urban systems and deepen their practical applications.
The event gathered outstanding global scholars to discuss cutting-edge technologies including artificial intelligence, digital twin, remote sensing, and spatiotemporal analytics. It also focused on multi-scale urban modeling approaches that address population, environmental, ecological, and infrastructural challenges, aiming to bridge theoretical research and practical policy solutions."
Opening Address: Urban Research Needs a Paradigm Shift
Professor Peng Gong, Vice-President (Academic Development) of the University of Hong Kong, delivered the opening remarks. He pointed out that traditional urban research, which relies heavily on qualitative descriptions and isolated case studies, falls short in addressing the complexities of modern urban governance. He emphasized that urban systems research must adhere to three core principles: interdisciplinary integration, quantitative modeling, and a global perspective — adopting quantitative models to support empirical qualitative judgments while conducting multi-scale studies that account for global capital flows, information technology, and population dynamics. Reflecting on China's urbanization journey, he expressed his hope that the new era of high-quality urban development would embrace a holistic, interdisciplinary systems mindset that highlights multi-objective synergies across social, economic, environmental, and health dimensions.
Institute Profile: Theory, Methods, Application — Three Pillars in One
Professor Bin Chen, Deputy Director of the Urban Systems Institute (USI), introduced the Institute's strategic direction. As a cross-faculty research platform at HKU, USI's core mission consists of two main pillars: to advance foundational theories of urban systems by integrating geography, ecology, economics, sociology, and other disciplines through remote sensing, big data, AI, and spatial modeling; and to drive research application by providing government and industry with practical solutions for urban governance and sustainable development.
The institute focuses on cutting-edge issues such as population spatiotemporal distribution, human settlements, and urban-rural sustainability, and is committed to conducting interdisciplinary collaborative research. Through academic forums, thematic workshops, and summer institutes, USI brings together scholars from around the world to contribute to the development of livable and sustainable cities globally.
Keynote Presentations
Professor Peng Gong delivered a speech entitled "The Exquisite City: Towards a New Theory for Sustainable Chinese Urban Development ". He proposed a new theoretical framework for "Exquisite City", which moves beyond a GDP-centric development model and establishes a new evaluation system with labor, capital, land, and carbon footprint as input dimensions, and encompassing 48 refined indicators covering health, inclusivity, prosperity, ecology, and livability. Based on empirical data from 148 Chinese cities over a decade, this framework provides a new evaluation paradigm for Chinese cities to transition toward refined, low-carbon, and sustainable high-quality development.
Professor Cindy Fan, Professor and Vice Provost for International Studies and Global Engagement at the University of California, Los Angeles (UCLA), delivered a speech titled "Shrinking Population in China: Policy, Social Changes, and Fertility Decline". She analyzed the structural causes of continuous population decline and persistent fertility decline. The "4-2-1 family structure" shaped by the one-child policy has increased childcare and elderly care costs, continuously suppressing fertility intentions. She emphasized that rising female education levels, increased workforce participation, urbanization, and high living costs are key drivers of sustained fertility decline. Simply incentivizing childbirth has limited effectiveness. Systemic reforms across multiple dimensions, including social institutions, family support, and social welfare, are necessary to effectively address the long-term challenges of population shrinkage and aging.
Professor John Wenzhong Shi, Chair Professor at The Hong Kong Polytechnic University, delivered a keynote speech titled "The Science of Urban Informatics". His research team pioneered the interdisciplinary field of urban informatics in 2013, and articulated five core dimensions of urban informatics: urban science, urban sensing, urban big data infrastructure, urban computing, and urban systems and applications. He demonstrated core technologies including GeoAI, mobile 3D mapping, and digital twin combining empirical cases like spatiotemporal pandemic risk prediction and real-scene modeling, illustrating how the discipline addresses complex urban challenges.
Professor Bo Huang, Chair Professor of the Department of Geography and the Deputy Director of USI at HKU, delivered a keynote speech titled "Toward a Mobility-Informed Urban Science". He noted that traditional urban research relies on static population and land statistics while overlooking human mobility as a core variable. He introduced his original GTWR (Geographically and Temporally Weighted Regression) model, demonstrating through pandemic transmission simulation and urban heatwave exposure assessment that mobility big data can accurately identify vulnerable populations and governance gaps. He advocated for deep integration of GIS, spatiotemporal intelligence, and urban-rural planning to support refined governance and low-carbon planning in high-density cities.
Professor Yong Li from Tsinghua University presented the "AI Urban Scientist" system, which integrates tens of thousands of urban research papers and multi-source data to automatically generate research hypotheses, fuse multi-source spatiotemporal data, complete simulations and empirical calculations, and output scientifically sound conclusions. This AI framework lowers the barrier to entry for urban data analysis, moving beyond its role as merely an auxiliary tool to actively explore urban system mechanisms and collaborates with planners in building fairer, more resilient, and sustainable urban spaces.
Professor Ying Long from Tsinghua University delivered a speech titled "Mid-Frequency Dynamics of Urban Streetscapes: Findings from Five Consecutive Years of Self-Collected Street View Imagery in Xining". He presented research based on five consecutive years of street view imagery collected in Xining, constructing a long-term dataset of over 225GB. After spatial alignment and frame extraction, more than 60% of sampling points obtained complete five-year continuous imagery coverage. The study fills a gap in mid-frequency urban street dynamics research, demonstrating that annual continuous street view monitoring can accurately identify renewal blind spots and environmental deficiencies, providing long-term monitoring method and empirical support for refined street governance and improved living quality.
Professor Martin Brandt, Associate Professor from the University of Copenhagen, delivered a speech titled "Canopy-Scale Long Term Tree Monitoring". His team developed a monitoring framework based on high-resolution satellite imagery and the U-Net deep learning model to automatically segment, locate, and measure individual tree crown width and height across large areas. Empirical validations across the African Sahel, France, and Danish woodlands accurately captured ecological disturbances from canopy degradation, logging, and climate stress. This monitoring system can be applied to urban forest resilience assessment and agroforestry management, providing more refined observational tools for sustainable urban ecology and global carbon cycle research.
Invited Presentations
Professor Shan Yin (Shanghai Jiao Tong University), Professor Xuecao Li (Sun Yat-sen University), and HKU scholars Assistant Professor Xiaohu Zhang, Assistant Professor Alec Kirkley, Assistant Professor Liqing Peng, Associate Professor Jun Ma, and Assistant Professor Yimeng Song also delivered frontier research presentations:
- Professor Shan Yin: Based on years of data from the Shanghai Urban Forest Ecological Positioning Station, and integrating satellite remote sensing and soundscape monitoring, he demonstrated that mixed forests offer significantly higher ecological benefits than pure stands, proposing strategies for stratified tree species allocation and coordinated urban-rural green space planning.
- Professor Xuecao Li: He constructed a multi-sector coupling modeling framework based on standardized geospatial data, integrating remote sensing, road networks, and industry statistics to achieve synchronized simulation of land expansion and carbon budgeting, providing a unified quantitative tool for regional sustainable planning.
- Professor Xiaohu Zhang: He constructed a three-tier spatial analysis framework across macro-, meso-, and micro-scales, quantifying the nonlinear effects of built environments on shared mobility behavior, providing data support for low-carbon transportation policies in high-density cities.
- Professor Alec Kirkley: He integrated statistical physics and Bayesian inference to develop an unsupervised network inference framework that automatically identifies urban structural patterns from noisy geographic data, providing new tools for spatial differentiation and transportation network optimization.
- Professor Liqing Peng: She compared the carbon emissions and supply potential of low-carbon bio-based materials, low-carbon concrete, and stabilized earth blocks. The feasibility of meeting global housing demand and carbon neutrality goals is assessed.
- Professor Jun Ma: He explored how general large-scale models can reshape built-environment research workflows, proposing a human-AI collaborative framework that improves efficiency while considering spatial common sense and interpretability.
- Professor Yimeng Song: He developed a healthy city monitoring framework integrating real-time GIS and GeoAI, achieving hourly dynamic mapping of environmental exposure and health risks, providing technical support for equitable healthy city planning.
Roundtable Discussions
The first roundtable, moderated by Professor Bin Chen, brought together keynote speakers including Professors Cindy Fan, John Shi, Bo Huang, Yong Li, Ying Long, and Martin Brandt. The discussion began with in-depth discussions on important scientific questions and key challenges in urban systems research, and further explored multi-scale analytical frameworks, problem-oriented research pathways, Global North-South differences, and the applications of digital technologies (particularly AI) in the context of demographic change. Scholars jointly explored the complex challenges and solutions within urban systems, analyzed related underlying mechanisms, and discussed the potential paths and impacts of emerging technologies such as AI in supporting sustainable development.
The second roundtable, moderated by Professor Yimeng Song, brought together invited speakers including Professors Shan Yin, Xuecao Li, Xiaohu Zhang, Alec Kirkley, Liqing Peng, and Jun Ma. The discussion delved into cutting-edge intelligent tools and low-carbon sustainable cities, analyzing the advantages and disadvantages of technologies such as real-time GIS, large-scale urban models, network inference, and long-term street view monitoring. It also explored the shortcomings such as algorithmic bias, computing power and energy consumption, and model interpretability. Furthermore, it expanded on low-carbon topics such as the supply of low-carbon building materials, the ecological value of urban forests, and multi-sectoral urban coupling modeling.
Closing Remarks
Finally, Professor Gong Peng delivered a closing remark, summarizing three core takeaways: the global urban landscape is evolving rapidly, population migration and mobility data serve as the fundamental basis for urban research, and artificial intelligence can effectively support academic research. He stressed that accurate understanding of population distribution, structure, and mobility is fundamental for formulating scientific policies. Additionally, he pointed out the widespread problem of overestimating population projections in academia using several classic cases. He noted that challenges such as population aging and labor shortages could be addressed through robotics and AI technologies. He reaffirmed that the core mission of urban systems research is to translate scientific findings into practical governance solutions that support the Earth's ecological carrying capacity and sustainable human settlements.
The successful convening of this Forum provided a platform for in-depth discussion on the challenges and opportunities faced by global cities. The diverse perspectives and insights shared will offer valuable inspiration and reference for future urban systems research and planning. The Institute will continue its commitment to fostering interdisciplinary collaboration and translating urban systems research into actionable solutions for real-world urban challenges, contributing to the development of sustainable cities globally.
About the Urban Systems Institute, The University of Hong Kong
The Urban Systems Institute (USI) is a pioneering cross-faculty research institute at HKU, dedicated to advance the sciences of urban systems and the applications of urban systems research. By reunifying the social and natural sciences, USI fosters a holistic approach to exploring the dynamic relationships between urban social and ecological systems. Through experimental research, the Institute bridges classical urban studies with investigations of contemporary, controversial, and futuristic normative systems, linking upstream future city and smart city research with downstream innovations in planning, design, management, and governance. To learn more, please visit our website: https://www.usi.hku.hk/
