HKU USI Summer Retreat 2026: Advancing the Urban Systems Science

From June 27 to 29, 2026, the Urban Systems Institute (USI) at The University of Hong Kong (HKU) successfully convened 2026 annual retreat and strategic workshop in Yangzhou, Jiangsu Province, China. This retreat brought together over twenty distinguished scholars across wide fields of remote sensing, urban planning, civil engineering, landscape architecture, public health, humanities, environmental health, and computer science. Throughout the intensive two-day workshop, participants shared their latest research progress and engaged in profound dialogues addressing core scientific questions and cutting-edge developments in urban systems science, collectively mapping out the future academic objectives and strategic planning for USI.

1. Opening Remark

Professor Peng Gong, Chair Professor of Global Sustainability, Vice-President and Pro-Vice-Chancellor (Academic Development) of HKU, delivered the opening remark. He extended a warm welcome to all participants and fondly recounted the original intention behind founding the Urban Systems Institute at The University of Hong Kong—to establish a globally oriented, highly distinctive, and frontier-leading research institute. He emphasized that this retreat is a critical step toward further exploring and realizing this grand vision. Outlining the strategic roadmap, he specified the core ethos as "rooted in China, facing the world," with a sharp focus on the critical, pressing, and anticipated challenges encountered throughout urban development. Concluding his remarks, Prof. Gong expressed his high expectations for interdisciplinary research collaborations, calling upon all colleagues to forge ahead together, pool their collective wisdom, and contribute significantly to the sustainable development of global urban systems.

2. Overview and Vision of Urban Systems Institute

Following the opening remark, Professor Bin Chen, Deputy Director (Interim) of USI and Associate Professor in Division of Landscape Architecture of HKU, delivered a thematic report on behalf of the institute. He first provided a comprehensive overview of USI’s development and vision, highlighting its core mission to confronting pivotal global challenges such as sustainable urban development, climate change, and environmental transformations. He pointed out that USI is actively constructing multi-scale coupled urban system models by integrating ubiquitous sensing, digital twins, and artificial intelligence. He then demonstrated the latest milestones achieved across the institute’s core research clusters, including healthy cities, land and housing systems, and urban-rural systems, alongside a series of high-impact research outputs published in top scientific journals such as the Nature and The Lancet series, while outlining the strategic blueprint for USI's upcoming development phases. During the panel session, the attending experts engaged in an enthusiastic and rigorous discussion centered around "the most critical core questions in urban systems science".

3. Research Deep Dive

Professor Chris Webster, the Chair Professor in the Department of Urban Planning and Design of HKU, delivered a presentation titled "Trigger thoughts for finding USI's cutting edge in multi-disciplinary urban systems science". He reviewed the evolution of urban science from Zipf's law to modern big data models, emphasizing the critical importance of balancing descriptive data distribution patterns with structural behavioral theories. He urged that USI should position itself at the forefront of understanding the behavioral mechanisms underlying urban big data and exploring new theoretical and modeling opportunities in urban shrinkage and scaling laws.

Professor Bo Huang, Chair Professor in Department of Geography and Deputy Director of USI of HKU, presented on "From human mobility to urban science". He pointed out that the essence of urban science lies in the dynamic interplay among Space, Agents, and Flows, with human mobility serving as the quintessential "flow" linking people, places, and urban functions. Prof. Huang demonstrated how high-resolution multi-source datasets, including mobile device trajectories and GPS data, can precisely measure human activity patterns. He showcased their successful application in epidemiological analytics through a mobility and contact-based SEIR (MC-SEIR), providing robust evidence-based support for public health interventions. Lastly, he advocated for discovering universal spatiotemporal scaling laws of mobility to transition from descriptive patterns to mechanistic explanations of urban structures, thereby bridging human mobility research with comprehensive urban systems science.

Professor Ge Lin Kan, Professor and Head of Thrust of Urban Governance and Design, Hong Kong University of Science and Technology (Guangzhou), gave a lecture titled "Spatial navigation, what can we learn from neurobiology". He highlighted his team’s groundbreaking trials on digital twin care for elderlies which combines virtual reality (VR), digital humans, and EEG-based cognitive workload tracking, personalizing cognitive interventions for elderly residents in Hong Kong. Clinical results confirmed that this dual physical-cognitive intervention effectively activates place-responsive cells and memory-triggering mechanisms in the brain, yielding significant clinical efficacy in mitigating cognitive decline and enhancing spatial orientation. Additionally, he explored the future potential of utilizing AI and digital twins to reconstruct urban layouts through a friendly "One-Meter City" perspective.

Professor W.S. (Wilson) LU, Chair Professor (Digital Construction) and Head of Department of Real Estate and Construction of HKU, presented "We AI (Almost) everything in our urban systems studies! What’s next?". He comprehensively elucidated the disruptive role of artificial intelligence in reshaping urban systems research, showcasing the iLab's latest breakthroughs in the field of smart construction. These innovations include the generative design of high-rise modular buildings using Graph Neural Networks (GNNs), as well as the processing of multi-source big urban data via Vision-Language Models (VLMs) to achieve high-precision 3D building reconstruction and panoramic analysis. Furthermore, he articulated an evolutionary logic for urban systems research methodologies, emphasizing the imperative transition from "using new AI tools to solve old questions" to "leveraging new AI tools to discover and address entirely new urban science questions." Looking ahead, he envisioned a broad horizon for innovating urban systems research paradigms driven by foundation large models.

Professor David Bishai, Division Head and Clinical Professor, School of Public Health of HKU, delivered a presentation titled "Update on climate and health in Hong Kong". He pointed out that extreme heatwaves have emerged as a highly lethal public health threat in Hong Kong, with heat-related excess mortality becoming an undeniable crisis that poses severe risks to vulnerable populations. Given the current lack of a unified heat-health action plan in Hong Kong, Prof. Bishai emphasized that effective intervention requires a multi-sectoral, city-scale collective action framework. He announced that the USI team will proactively convene legislative councilors, meteorological authorities, and community stakeholders to push forward the formulation of Hong Kong's first comprehensive action plan.

Professor Bin Jiang, Associate Professor in Division of Landscape Architecture of HKU, spoke on "Healing the land, healing the soul". He highlighted his team's long-term empirical research focusing on perceived oppressiveness and resident stress within high-density urban environments, proposing a quantified nature resolution. He recommended that urban dwellers maintain an approximately 6 hours of physical exposure to natural environments and 8 hours of visual access to natural landscapes per week to achieve optimal mental restoration. Furthermore, he elaborated on an innovative "Digital Twin Cycling Intervention for the Elderly" experiment conducted in Hong Kong, which integrated VR and digital human technologies. The research findings not only validated the system's clinical efficacy in enhancing cognitive health among elderlies but also further demonstrated its positive role in alleviating their mental workload.

Professor Xiaohu Zhang, Assistant Professor in the Department of Urban Planning and Design of HKU, presented on "How cities evolve in technology space". He delved into the positioning and shifting trajectories of cities within the global technological evolution network, highlighting a prevailing trend of "declining technological differentiation" across the vast majority of cities, which signifies an increasing homogenization in the inter-city technological division of labor. By introducing an evolutionary model grounded in the mechanisms of "Exploitation" and "Exploration," Prof. Zhang elucidated the profound impact of technological path dependency on the urban innovation landscape. His research offers deep theoretical insights into how cities dynamically calibrate their positions within the technology space through strategic imitation or selective breakthroughs.

Professor Xintao Yan, Assistant Professor in Department of Civil Engineering in HKU, gave a presentation titled "Traffic world models and behavioral safety evaluation of autonomous vehicles". He detailed a deep learning-based simulation framework named "NeuralNDE," which achieves high-fidelity reproduction of human driving behavior and multi-sensor data, thereby statistically mirroring real-world driving environments within a virtual setting. By introducing naturalistic and adversarial driving environment (NADE) modeling and deep reinforcement learning methods, this technology dramatically accelerates autonomous vehicle safety testing by approximately 5,000 times without compromising accuracy, effectively addressing the industry-wide pain point of excessive testing time for extreme safety-critical scenarios.

Professor Frank van der Wouden, Assistant Professor in Department of Geography of HKU, presented "Academic Mobility Reallocates Access to Scientific Knowledge". By constructing a large-scale database of academic mobility, he provided an in-depth exploration of how scientific mobility systems exacerbate inequalities in knowledge access across cities. He reveals that while academic collaboration is increasingly globalized and cross-regional, "local collaboration" remains irreplaceable in terms of knowledge output and learning effects, with local knowledge access serving as a cornerstone for enhancing academic productivity. He proposed utilizing a natural experiment approach to precisely compare the knowledge output of scholars who relocate versus those who remain, providing a scientific explanation for global talent mobility, technological innovation disparities, and their underlying mechanisms.

4. Outdoor Activities

The retreat not only sparked intellectual brilliance within the seminar hall but also allowed participants to immerse themselves in the deep cultural heritage of Yangzhou through a tailored outdoor field experience. This outdoor activity and cultural interaction provided the scholars with an immersive experience of the spatial layout aesthetics and dimensions of classical oriental gardens. Furthermore, it ignited profound resonances regarding urban water systems, historical heritage, and ecological landscape conservation, providing a vivid practical context for subsequent discussions on urban resilience and livability.

The successful conclusion of the USI Retreat in Yangzhou not only facilitated profound dialogues on the complex relationship between human civilization and urban development in the AI era but also further solidified the research consensus of USI. Looking ahead, the Urban Systems Institute will continue to contribute oriental wisdom and scientific paradigms to the sustainable, resilient, and livable development of global cities.