Mobility trajectories are essential for understanding urban dynamics and enhancing urban planning, yet access to such data is frequently hindered by privacy concerns. This research introduces a transformative framework for generating large-scale urban mobility trajectories, employing a novel application of a transformer-based model pre-trained and fine-tuned through a two-phase process. Initially, trajectory generation is conceptualized as an offline reinforcement learning (RL) problem, with a significant reduction in vocabulary space achieved during tokenization. The integration of Inverse Reinforcement Learning (IRL) allows for the capture of trajectory-wise reward signals, leveraging historical data to infer individual mobility preferences. Subsequently, the pre-trained model is fine-tuned using the constructed reward model, effectively addressing the challenges inherent in traditional RL-based autoregressive methods, such as long-term credit assignment and handling of sparse reward environments. Comprehensive evaluations on multiple datasets illustrate that our framework markedly surpasses existing models in terms of reliability and diversity. Our findings not only advance the field of urban mobility modeling but also provide a robust methodology for simulating urban data, with significant implications for traffic management and urban development planning. The implementation is publicly available at https://github.com/Wangjw6/TrajGPT_R.
Self-organized free-flight arrival for urban air mobility
Technische Universität Dresden(德累斯顿工业大学);Center for Scalable Data Analytics and Artificial Intelligence (ScaDS.AI)(可扩展数据分析与人工智能中心(ScaDS.AI));Institute of Flight Systems, Universität der Bundeswehr München(慕尼黑联邦国防军大学飞行系统研究所)
University of Illinois, Urbana-Champaign(伊利诺伊大学厄巴纳-香槟分校);NASA Langley Research Center(美国国家航空航天局兰利研究中心);Skygrid LLC(Skygrid有限责任公司)
This work considers the scheduling problem for Urban Air Mobility (UAM) vehicles travelling between origin-destination pairs with both hard and soft trip deadlines. Each route is described by a discrete probability distribution over trip completion times (or delay) and over inter-arrival times of requests (or demand) for the route along with a fixed hard or soft deadline. Soft deadlines carry a cost that is incurred when the deadline is missed. An online, safe scheduler is developed that ensures that hard deadlines are never missed, and that average cost of missing soft deadlines is minimized.…
Airspace models have played an important role in the development and evaluation of aircraft collision avoidance systems for both manned and unmanned aircraft. As Urban Air Mobility (UAM) systems are being developed, we need new encounter models that are representative of their operational environment. Developing such models is challenging due to the lack of data on UAM behavior in the airspace. While previous encounter models for other aircraft types rely on large datasets to produce realistic trajectories, this paper presents an approach to encounter modeling that instead relies on expert kno…
University of Maryland(马里兰大学);University of Tehran(德黑兰大学);Sharif University of Technology(谢里夫理工大学)
Urban air mobility is the new mode of transportation aiming to provide a fast and secure way of travel by utilizing the low-altitude airspace. This goal cannot be achieved without the implementation of new flight regulations which can assure safe and efficient allocation of flight paths to a large number of vertical takeoff/landing aerial vehicles. Such rules should also allow estimating the effective capacity of the low-altitude airspace for planning purposes. Path planning is a vital subject in urban air mobility which could enable a large number of UAVs to fly simultaneously in the airspace…
It has been considered that urban air mobility (UAM), also known as drone-taxi or electrical vertical takeoff and landing (eVTOL), will play a key role in future transportation. By putting UAM into practical future transportation, several benefits can be realized, i.e., (i) the total travel time of passengers can be reduced compared to traditional transportation and (ii) there is no environmental pollution and no special labor costs to operate the system because electric batteries will be used in UAM system. However, there are various dynamic and uncertain factors in the flight environment, i.…
Rethinking Urban Mobility Prediction: A Super-Multivariate Time Series Forecasting Approach
Sichuan University(四川大学);The Hong Kong University of Science and Technology (Guangzhou)(香港科技大学(广州));McGill University(麦吉尔大学);Shanghai Jiao Tong University(上海交通大学);Shanghai AI Lab(上海人工智能实验室)
Synergistic Fusion of Topological Structure and Temporal Semantics of Mobility for Urban Region Embedding
Urban AI Institute, Korea Advanced Institute of Science and Technology (KAIST)(韩国科学技术院城市人工智能研究院);Graduate School of Data Science, KAIST(韩国科学技术院数据科学研究生院);Department of Industrial Engineering and Systems, KAIST(韩国科学技术院工业工程与系统系);Department of Civil and Environmental Engineering, KAIST(韩国科学技术院土木与环境工程系)
Commute Networks as a Signature of Urban Socioeconomic Performance: Evaluating Mobility Structures with Deep Learning Models
Department of Mathematics and Statistics Faculty of Science, Masaryk University(数学与统计学系,科学学院,马萨里克大学);Center for Urban Science + Progress New York University(城市科学与进步中心,纽约大学)
Beijing National Research Center for Information Science and Technology(北京信息科学与技术国家研究中心);Tsinghua University(清华大学);University of Helsinki(赫尔辛基大学);The Hong Kong University of Science and Technology(香港科技大学)
Understanding urban dynamics, i.e., how the types and intensity of urban residents' activities in the city change along with time, is of urgent demand for building an efficient and livable city. Nonetheless, this is challenging due to the expanding urban population and the complicated spatial distribution of residents. In this paper, to reveal urban dynamics, we propose a novel system UrbanRhythm to reveal the urban dynamics hidden in human mobility data. UrbanRhythm addresses three questions: 1) What mobility feature should be used to present residents' high-dimensional activities in the city…
Singapore University of Technology and Design (SUTD)(新加坡科技设计大学)
In this paper, we present an unsupervised learning approach to identify the user points of interest (POI) by exploiting WiFi measurements from smartphone application data. Due to the lack of GPS positioning accuracy in indoor, sheltered, and high rise building environments, we rely on widely available WiFi access points (AP) in contemporary urban areas to accurately identify POI and mobility patterns, by comparing the similarity in the WiFi measurements. We propose a system architecture to scan the surrounding WiFi AP, and perform unsupervised learning to demonstrate that it is possible to ide…
As the demand for mobility in our society seems to increase, the various issues centered on urban mobility are among those that worry most city inhabitants in this planet. For instance, how to go from A to B in an efficient (but also less stressful) way? These questions and concerns have not changed even during the covid-19 pandemic; on the contrary, as the current stand, people who are avoiding public transportation are only contributing to an increase in the vehicular traffic. The are of intelligent transportation systems (ITS) aims at investigating how to employ information and communicatio…
FloGAN: Scenario-Based Urban Mobility Flow Generation via Conditional GANs and Dynamic Region Decoupling
Future Cities Laboratory Global(未来城市实验室全球);Singapore-ETH Centre(新加坡-ETH中心);College of Computing and Data Science(计算与数据科学学院);Nanyang Technological University(南洋理工大学);Department of Civil Engineering and Engineering Mechanics(土木工程与工程力学系);Columbia University(哥伦比亚大学)
Institute for Clarity in Documentation(文档清晰度研究所);Brookhaven Laboratories(布鲁克海文实验室);NASA Ames Research Center(美国国家航空航天局艾姆斯研究中心);Palmer Research Laboratories(帕尔默研究实验室);Inria Paris-Rocquencourt(法国国家信息与自动化研究所巴黎-罗克库尔中心);Rajiv Gandhi University(拉吉夫·甘地大学);Tsinghua University(清华大学);University of Pittsburgh(匹兹堡大学)
Which area in NYC is the most similar to Lower East Side? What about the NoHo Arts District in Los Angeles? Traditionally this task utilizes information about the type of places located within the areas and some popularity/quality metric. We take a different approach. In particular, urban dwellers' time-variant mobility is a reflection of how they interact with their city over time. Hence, in this paper, we introduce an approach, namely hood2vec, to identify the similarity between urban areas through learning a node embedding of the mobility network captured through Foursquare check-ins. We co…
Mobility-on-demand (MoD) systems represent a rapidly developing mode of transportation wherein travel requests are dynamically handled by a coordinated fleet of vehicles. Crucially, the efficiency of an MoD system highly depends on how well supply and demand distributions are aligned in spatio-temporal space (i.e., to satisfy user demand, cars have to be available in the correct place and at the desired time). To do so, we argue that predictive models should aim to explicitly disentangle between temporal} and spatial variability in the evolution of urban mobility demand. However, current appro…
Beyond travel mode: urban context shapes active mobility's mental health effects over time
Martin Centre for Architectural and Urban Studies, University of Cambridge(剑桥大学马丁建筑与城市研究中心);Cambridge Public Health, University of Cambridge(剑桥大学剑桥公共卫生)
The Hong Kong Polytechnic University(香港理工大学);MIT(麻省理工学院);Universidad Carlos III de Madrid(马德里卡洛斯三世大学)
Urbanization and its problems require an in-depth and comprehensive understanding of urban dynamics, especially the complex and diversified lifestyles in modern cities. Digitally acquired data can accurately capture complex human activity, but it lacks the interpretability of demographic data. In this paper, we study a privacy-enhanced dataset of the mobility visitation patterns of 1.2 million people to 1.1 million places in 11 metro areas in the U.S. to detect the latent mobility behaviors and lifestyles in the largest American cities. Despite the considerable complexity of mobility visitatio…