Disaster has a great impact on human mobility patterns. Clustering mobility patterns by generalizing group level characteristics from diverse individual trajectories plays a vital role in informing post-disaster recovery strategies. However, predefined clustering criteria or supervised labeling alone are insufficient to adequately capture the dynamics of mobility patterns during disaster events. Besides, the existing methods are not enough to capture the sensitive changes in mobility patterns in disaster events and handle the data of high-dimensional. This research investigates an embedded deep learning-based method which can automatically extract the groups' short-term feature of mobility patterns and achieves short-term mobility pattern clustering during disaster. The proposed method employs a Transformer-based temporal encoder to capture intra-day sequence patterns and integrates a VAE component with an embedded latent variable that directly encodes group-level mobility modes. We also design a compactness–separation loss that explicitly encourages within-mode feature compactness and between-mode feature separation. Based on massive mobile data, we conduct mobility pattern clustering on the case of 2011 Fukushima Earthquake. Compared to conventional clustering approaches, the proposed model structure is more discriminative and can capture the more sensitive changes between pre- and post- events. Compared to baselines with different loss functions, proposal methods can make more accurate fitting result and obtain more discrete clusters modes. Additionally, sensitivity analysis is conducted to examine the influence of key hyper parameters within the model. Based on the clustering outcomes, five representative mobility patterns are identified. We further analyze the spatial-temporal characteristics of mobility pattern changes during the disaster events and the recovery period of mobility pattern.

Enhancing the energy efficiency of buildings significantly relies on monitoring indoor ambient temperature. The potential limitations of conventional temperature measurement techniques, together with the omnipresence of smartphones, have redirected researchers' attention towards the exploration of phone-based ambient temperature estimation methods. However, existing phone-based methods face challenges such as insufficient privacy protection, difficulty in adapting models to various phones, and hurdles in obtaining enough labeled training data. In this study, we propose a distributed phone-based ambient temperature estimation system which enables collaboration among multiple phones to accurately measure the ambient temperature in different areas of an indoor space. This system also provides an efficient, cost-effective approach with a few-shot meta-learning module and an automated label generation module. It shows that with just 5 new training data points, the temperature estimation model can adapt to a new phone and reach a good performance. Moreover, the system uses crowdsourcing to generate accurate labels for all newly collected training data, significantly reducing costs. Additionally, we highlight the potential of incorporating federated learning into our system to enhance privacy protection. We believe this study can advance the practical application of phone-based ambient temperature measurement, facilitating energy-saving efforts in buildings.

Monitoring the crowd in urban hot spot has been an important research topic in the field of urban management and has high social impact. It can allow more flexible allocation of public resources such as public transportation schedule adjustment and arrangement of police force. After 2020, because of the epidemic of COVID-19 virus, the public mobility pattern is deeply affected by the situation of epidemic as the physical close contact is the dominant way of infection. In this study, we propose a confirmed case-driven time-series prediction of crowd in urban hot spot named MobCovid. The model is a deviation of Informer, a popular time-serial prediction model proposed in 2021. The model takes both the number of nighttime staying people in downtown and confirmed cases of COVID-19 as input and predicts both the targets. In the current period of COVID, many areas and countries have relaxed the lockdown measures on public mobility. The outdoor travel of public is based on individual decision. Report of large amount of confirmed cases would restrict the public visitation of crowded downtown. But, still, government would publish some policies to try to intervene in the public mobility and control the spread of virus. For example, in Japan, there are no compulsory measures to force people to stay at home, but measures to persuade people to stay away from downtown area. Therefore, we also merge the encoding of policies on measures of mobility restriction made by government in the model to improve the precision. We use historical data of nighttime staying people in crowded downtown and confirmed cases of Tokyo and Osaka area as study case. Multiple times of comparison with other baselines including the original Informer model prove the effectiveness of our proposed method. We believe our work can make contribution to the current knowledge on forecasting the number of crowd in urban downtown during the Covid epidemic.

Activity pattern prediction is a critical part of urban computing, urban planning, intelligent transportation, and so on. Based on a dataset with more than 10 million GPS trajectory records collected by mobile sensors, this research proposed a CNN-BiLSTM-VAE-ATT-based encoder-decoder model for fine-grained individual activity sequence prediction. The model combines the long-term and short-term dependencies crosswise and also considers randomness, diversity, and uncertainty of individual activity patterns. The proposed results show higher accuracy compared to the ten baselines. The model can generate high diversity results while approximating the original activity patterns distribution. Moreover, the model also has interpretability in revealing the time dependency importance of the activity pattern prediction.

Life pattern clustering is essential for abstracting the groups' characteristics of daily life patterns and activity regularity. Based on millions of GPS records, this research proposes a framework on the life pattern clustering which can efficiently identify the groups that have similar life patterns. The proposed method can retain original features of individual life pattern data without aggregation. Metagraph-based data structure is proposed for presenting the diverse life pattern. Spatial-temporal similarity includes significant places semantics, time-sequential properties and frequency are integrated into this data structure, which captures the uncertainty of an individual and the diversities between individuals. Non-negative-factorization-based method is utilized for reducing the dimension. The results show that our proposed method can effectively identify the groups that have similar life pattern in long term and takes advantage in computation efficiency and representational capacity compared with the traditional methods. We reveal the representative life pattern groups and analyze the group characteristics of human life patterns during different periods and different regions. We believe our work helps in future infrastructure planning, services improvement and policy making related to urban and transportation, thus promoting a humanized and sustainable city.

In this paper, an innovative fuzzy group decision-making model is designed for assessing regional transportation sustainability, focusing on the correlation between various attributes of the evaluation system. The focus of this model is the partitioned Maclaurin symmetric mean operator because of its better applicability when considering attribute correlation and attribute grouping. The modified spherical fuzzy partitioned Maclaurin symmetric mean operator is proposed, which has superior application scope. Its weighted form and special cases are discussed. Then, the extended statistical variance method and the evidence-based Bayes approximation method are used to obtain weight vectors of attributes and experts. In addition, a fuzzy assessment model of sustainable transportation is developed. Finally, a numerical example of regional transportation sustainability assessment and a comparison with previous studies are presented to illustrate the feasibility and universality of this method.

To date immunity to disruptions of multi-scale urban road networks (URNs) has not been effectively quantified. This study uses robustness as a meaningful - if partial - representation of immunity. We propose a novel Relative Area Index (RAI) based on traffic assignment theory to quantitatively measure the robustness of URNs under global capacity degradation due to three different types of disruptions, which takes into account many realistic characteristics. We also compare the RAI with weighted betweenness centrality, a traditional topological metric of robustness. We employ six realistic URNs as case studies for this comparison. Our analysis shows that RAI is a more effective measure of the robustness of URNs when multi-scale URNs suffer from global disruptions. This improved effectiveness is achieved because of RAI’s ability to capture the effects of realistic network characteristics such as network topology, flow patterns, link capacity, and travel demand. Also, the results highlight the importance of central management when URNs suffer from disruptions. Our novel method may provide a benchmark tool for comparing robustness of multi-scale URNs, which facilitates the understanding and improvement of network robustness for the planning and management of URNs.

Long-term pedestrian trajectory prediction in crowds is highly valuable for safety driving and social robot navigation. The recent research of trajectory prediction usually focuses on solving the problems of modeling social interactions, physical constraints and multi-modality of futures without considering the generalization of prediction models to other scenes and objects, which is critical for real-world applications. In this paper, we propose a general framework that makes trajectory prediction models able to transfer well across unseen scenes and objects by quickly learning the prior information of trajectories. The trajectory sequences are closely related to the circumstance setting (e.g. exits, roads, buildings, entries etc.) and the objects (e.g. pedestrians, bicycles, vehicles etc.). We argue that those trajectory information varying across scenes and objects makes a trained prediction model not perform well over unseen target data. To address it, we introduce MetaTraj that contains carefully designed sub-tasks and meta-tasks to learn prior information of trajectories related to scenes and objects, which then contributes to accurate long-term future prediction. Both sub-tasks and meta-tasks are generated from trajectory sequences effortlessly and can be easily integrated into many prediction models. Extensive experiments over several trajectory prediction benchmarks demonstrate that MetaTraj can be applied to multiple prediction models and enables them generalize well to unseen scenes and objects.

Human mobility similarity comparison plays a critical role in modeling city dynamics, which exerts an enormous impact on developing intelligent transportation system. By expanding origin-destination matrix, we propose a mobility expression named mobility tableau and corresponding similarity measurement approach. Compared with traditional Origin-Destination matrix-based mobility comparison, mobility tableau comparison provides multi-dimensional similarity information, including volume similarity, spatial similarity, mass inclusiveness and structure similarity. The robustness of the measure is supported through several sensitive analysis based on real Global Positioning System dataset. The better performance of our proposed approach compared with traditional methods in two case studies including Call Detail Record based mobility tableau validation and different cities’ mobility comparison also demonstrates the practicality and superiority of our method.

The fast growing of e-commerce makes the express delivery an important component of transportation system. Absent delivery as one of the main reasons of failed delivery, brings serious waste of resources every year. Although with the development of Internet of Things technology, positioning system of recipients’ mobile devices can provide location information to help delivery routing optimization solving absent delivery, the lack of security makes it not practical. This paper proposes an IoT positioning technology based intelligent delivery system by introducing blockchain system and location information encryption, which overcomes three fatal problems of traditional IoT positioning technology based system: different party shares all information, location information interaction is too exposed and the system is unattractive to recipients. A set of analysis with real case experiment about efficiency improvement, incentive effect and security are conducted to validate the robustness of the system. Compared with previous research, the proposed system not only has high accuracy by utilizing real-time location information instead of unreliable prediction results, but also possesses high security.

How to effectively extract identifiable information from human mobility data and distinguish different agents is a significant topic for location-based services and intelligent transportation systems, which is described as the Human Mobility Signature Identification problem. A deeper understanding of the identifiable information underlain in human mobility can help us lay the foundation for applications such as irregular user behavior detection and privacy protection. However, human mobility comprises a mixture of different mobility patterns, traditional methods usually pay more attention to spatial-temporal features, while pattern dimension feature is usually ignored, which makes the result very dependent on the population agglomeration degree. To bridge the research gap, in this paper, we propose a novel Life-Travel pattern-based learning module (LTP-Net), in which spatial-temporal-pattern dimension features are embedded together to provide more comprehensive information for individual identification. A real-world mobile phone location dataset is utilized to evaluate the performance of the proposed LTP-Net and traditional methods. Several case studies are also conducted to analyze the model performance, including the abnormal behavior detection for the east Japan earthquake.

Aggregating crowd density in grids from big mobile datasets is a basic but critical work in urban computing and mobile computing. The error of position estimation in raw mobile data, including spatial deviation and temporal deviation, is inevitable and directly impacts the accuracy of aggregated crowd density results. In this case, a key modifiable areal unit problem is raised to understand the relationship among the crowd density accuracy, raw mobile data error, grid shape, and size, but few studies focused on it. This paper analyzes this modifiable areal unit problem of the error in crowd density estimation from big mobility data. By regarding the error as the result of a convolution operation, an optimization model based restoration method was proposed to fix the error of the estimated result, and we analyzed the restoration effect under different circumstances by several simulation experiments. A real application for grided population distribution map construction and restoration from Call Detail Record was conducted to prove the reliability of the whole analysis, which demonstrates the restoration method can reduce the error by nearly 40% under certain conditions.

Recent decades have seen a significant increase in the frequency, intensity, and impact of natural disasters and other emergencies, forcing the governments around the world to make emergency response and disaster management national priorities. The growth of extremely large and complex datasets—commonly referred to asbig data—and various advances in information and communications technology and computing now support more effective approaches to humanitarian relief, logistical coordination, overall disaster management, and long-term recovery in connection with natural disasters and emergency events. Leveraging big data and technological advances for emergency management has attracted considerable attention in the research community. However, the desired merging ofbig data and emergency management(BDEM) requires coordinated efforts to align and define interdisciplinary terminologies and methodologies. To date, the key concepts and technologies in this emerging research area have not been coherently discussed in a sufficiently broad and multidisciplinary manner. In this article, an international team presents an overview of the BDEM domain, highlighting a general framework and discussing key challenges from several perspectives. We introduce and summarize typical technologies and applications, organized into the six broad categories of remote sensing, resilient communication networks, mobile communication networks, human mobility and urban sensing, social network analysis, and knowledge graphs. Finally, we outline several directions of future research.

We consider long-term path forecasting problems in crowds, where future sequence trajectories are generated given a short observation. Recent methods for this problem have focused on modeling social interactions and predicting multi-modal futures. However, it is not easy for machines to successfully consider social interactions, such as avoiding collisions while considering the uncertainty of futures under a highly interactive and dynamic scenario. In this paper, we propose a model that incorporates multiple interacting motion sequences jointly and predicts multi-modal socially acceptable distributions of futures. Specifically, we introduce a new aggregation mechanism for social interactions, which selectively models long-term inter-related dynamics between movements in a shared environment through a message passing mechanism. Moreover, we propose a loss function that not only accesses how accurate the estimated distributions of the futures are but also considers collision avoidance. We further utilize mixture density functions to describe the trajectories and learn the multi-modality of future paths. Extensive experiments over several trajectory prediction benchmarks demonstrate that our method is able to forecast socially acceptable distributions in complex scenarios.

Accurate human path forecasting in complex and crowded scenarios is critical for collision avoidance of autonomous driving and social robots navigation. It still remains as a challenging problem because of dynamic human interaction and intrinsic multimodality of human motion. Given the observation, there is a rich set of plausible ways for an agent to walk through the circumstance. To address those issues, we propose a spatio-temporal model that can aggregate the information from socially interacting agents and capture the multimodality of the motion patterns. We use mixture density functions to describe the human path and predict the distribution of future paths with explicit density. To integrate more factors to model interacting people, we further introduce a coordinate transformation to represent the relative motion between people. Extensive experiments over several trajectory prediction benchmarks demonstrate that our method is able to forecast various plausible futures in complex scenarios and achieves state-of-the-art performance.

Based on inverse hydraulic-thermodynamic transient analyses and on an improved particle swarm optimization (PSO), a leak detection and localization method is proposed for liquid pipelines. The finite volume method is employed to numerically model the continuity, momentum, and energy equations. To determine the optimum-improved PSO algorithm and corresponding parameters, four types of algorithms were used for the analyses of a virtual pipeline. Accuracy, stability, robustness, and false alarm rate tests were conducted. The SIPSO algorithm has been shown to outperform the other algorithms. Two oil pipelines were utilized as example cases in conjunction with the use of the SIPSO algorithm. One of these pipelines was involved in a field opening experiment, while the other was involved in a real leak accident. The results demonstrated that smaller relative errors were achieved with the proposed method for the estimations of the location, coefficient, and starting time of the leak.