Modeling UK's national railway network. More stories here
Connectivity and community structure in the London bike sharing system. More stories here
A big-data approach to analyzing urban metro ridership in Beijing. More stories here
Modeling of passenger queuing and crowding at a major international train station
Simulation of Shanghai metro system. Youtube link here
Reduction of Black Carbon concentration in West Glasgow after applying intelligent traffic signal control and variable message sign. Negative values indicate reduction (the CARBOTRAF project)
Dr Han's research focuses on developing models and methodologies for the design and management of complex transport systems, with social, economic, environmental, and technological dimensions. This is achieved by combining modern mobility concepts and data with the tools of mathematics, statistics, operations research, and artificial intelligence. This underpins the areas of research below.
(1) TRANSPORT NETWORK MODELING.
He have been developing novel techniques for modelling dynamic network traffic at microscopic, mesoscopic, and macroscopic scales. This is done with varying levels of temporo-spatial granularities, travellers’ behavioural uncertainties, and penetration of disruptive technologies to address the challenges of predicting large-scale urban transport networks and supporting transport authorities with decisions regarding the planning and management of network infrastructure and users. Focus is also placed on the analytical properties and mathematical rigor of the developed models.
(2) TRANSPORT OPERATION & MANAGEMENT.
Dr Han has been focusing on the optimisation of urban transport systems in terms of efficiency, capacity, safety, and environmental impact. He has been applying innovative optimisation and control techniques such as robust optimisation, bi-level optimisation, deep reinforcement learning, and meta-heuristics to traffic network design, congestion charging, signal control, and route guidance. Such techniques have been combined with (1) to demonstrate the impact of these optimisation solutions.
(3) SUSTAINABLE TRANSPORT.
He has extended his modelling capabilities to address vehicle emissions and air pollutant concentration, by combining car traffic dynamics with engine performance models to estimate traffic emissions at individual vehicle, road segment, and network levels. Such estimation is further connected to public health impact by analysing the temporal and spatial distributions of pollutants given weather and atmospheric conditions. He has also successfully developed multi-objective optimisation and real-time control strategies to reduce traffic congestion and public exposure, and demonstrate their impacts in a real-world test environment.
(4) AIR TRAFFIC MANAGEMENT.
His work in this regard focuses on improving flow capacity and reducing delays in existing air traffic systems including airport ground surface, terminal areas, and air traffic networks. This is achieved by offering novel air traffic flow models and control frameworks that have been validated using empirical data, subject matter experts, and high-fidelity simulations. By working with US, European, and Chinese authorities, he is seeking real-world impact of these solutions and evidence of transferability of the developed models and techniques.
(5) BIG DATA ANALYSIS.
His work in this regard is three-fold: (i) utilise multi-source and heterogeneous urban and transport data to analyse urban mobility patterns, identify key bottlenecks and inefficiencies, and make recommendations regarding transport planning and management; (ii) apply machine/deep learning techniques to obtain results and insights (e.g. traffic prediction, pattern recognition) unavailable through conventional math/stat/engineering tools; (iii) leverage Internet of Things and cloud computing to generate and evaluate new forms of urban mobility services (e.g. ride sharing, bike sharing, e-hailing). His work overlaps with urban logistics, retail, e-commerce, and public health, and draws upon interdisciplinary research on an international level.
- Co-Investigator. Post Brexit impact analysis on M20/A20 motorway congestion, BBC, 2018 (GBP 6k)
- Principal Investigator. Intelligent mobile sensing network for measuring air quality in urban micro-environment. Deheng Information Ltd., 2017-2018 (GBP 34k)
- Principal Investigator. Newton Fund Researcher Links Workshop, Newton Fund, 2017 (GBP 24k).
- Principal Investigator. College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, start-up funds, 2016-2019 (RMB 150k).
- Principal Investigator. Mitigating urban traffic emissions based on big data in traffic and air quality. Imperial College – Zhejiang University Exchange Program, 2016-2018 (RMB 400k)
- Co-Investigator. Passenger growth forecasts for international passengers departing from St Pancras. HighSpeed 1, 2015 (GBP 60k).
- Principal Investigator. CARBOTRAF – A decision support system for reducing CO2 and Black Carbon emissions by adaptive traffic management. 7th EU Framework Program, 2011-2015 (EUR 450k).
- Named Researcher. Robust and dynamic prototyping of strategies for sustainable network congestion manage- ment. US National Science Foundation, 2013-2017 (USD 250k).
- Participant. A theory of complex transportation network design. US National Science Foundation, 2010-2013 (USD 310k).
College of Civil Aviation, Nanjing University of Aeronautics and Astronautics, Air traffic flow management, 2015
Reducing air pollution with smart transportation, Smart City in the Big Data Era Summit, the Big Data Expo, Guiyang, Guizhou, China, 2017
Real-time traffic management: challenges and solutions, Institute for Transport Studies, University of Leeds, Leeds, UK, 2016
An analytical approach to sustainable transportation network design, Transportation Research Board Doctoral Dissertation Workshop on Transportation Modeling, Washington DC, USA, 2014
Statistical metamodeling of dynamic network loading and application to dynamic traffic assignment, University of New South Wales, Sydney, NSW, Australia, 2016
On the continuum approximation of the on-and-off signal control on dynamic traffic networks, Institut Henri Poincaré, Paris, 2014
The mathematical foundation of dynamic user equilibria, Workshop on ANalysis and COntrol on NETwork (ANCONET), University of Padova, Italy, 2016
Data-driven decision rule approach for real-time traffic management, Transportation Research Board Traffic Flow Theory and Characteristics Committee, ISTTT21 Webinar Series, 2016
On some theoretical and practical aspects of traffic signal control, Southwest Jiaotong University, Chengdu, Sichuan, China, 2015
Optimization of operations in multi-airport systems, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, China, 2016
Data-driven decision rule approach for real-time traffic management, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, China, 2016
Dynamic traffic flow on networks (Tutorial), University of Sydney, Sydney, New South Wales, Australia, 2016
Dynamic user equilibrium: A differential game perspective (Tutorial), University of Sydney, Sydney, New South Wales, Australia, 2016
Traffic operation facilitated by telecommunication: Some case studies, Transportation Research Board Chan Wui & Yunyin Rising Star Workshop, USA, 2016
How to publish your research in scientific journals, Nanjing University of Aeronautics and Astronautics, Nanjing, Jiangsu, China, 2016
Optimization of operations in multi-airport systems, Dalian Maritime University, Dalian, Liaoning, China, 2016
Some aspects of real-time traffic control & management, Zhejiang University, Hangzhou, Zhejiang, China, 2016