Xuecai(Daniel) Xu

Dr. Xuecai(Daniel) Xu

orcid

Research Focus & Metrics

Academic Career Length

12Years (2015-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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13 September 2019 in IEEE Access
Verified
Journal Article
Open access
GDGuowen Dai
Guowen Dai
CMChangxi Ma
Changxi Ma
XXXuecai(Daniel) Xu
Xuecai(Daniel) Xu
Accurate short-term traffic forecasts help people choose transportation and travel time. Through the query data, many models for traffic flow prediction have neglected the temporal and spatial correlation of traffic flow, so that the prediction accuracy is limited by the accuracy of traffic data. This paper proposed a short-term traffic flow prediction model that combined the spatio-temporal analysis with a Gated Recurrent Unit (GRU). In the proposed prediction model, firstly, time correlation analysis and spatial correlation analysis were performed on the collected traffic flow data, and then the spatiotemporal feature selection algorithm was employed to define the optimal input time interval and spatial data volume. At the same time, the selected traffic flow data were extracted from the actual traffic flow data and converted into a two-dimensional matrix with spatio-temporal traffic flow information. The GRU was used to process the spatio-temporal feature information of the internal traffic flow of the matrix to achieve the purpose of prediction. Finally, the prediction results obtained by the proposed model were compared with the actual traffic flow data to verify the effectiveness of the model. The model proposed in this paper was compared with the convolutional neural network (CNN) model and the GRU model, and the results show that the proposed method outperforms both in accuracy and stability.

2 February 2022 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
CMChangxi Ma
Changxi Ma
YZYongpeng Zhao
Yongpeng Zhao
GDGuowen Dai
Guowen Dai
XXXuecai(Daniel) Xu
Xuecai(Daniel) Xu
SWSze-Chun Wong
Sze-Chun Wong
Short-term traffic speed prediction is fundamental to intelligent transportation systems (ITS), and the accuracy of the model largely determines the performance of real-time traffic control and management. In this study, a short-term traffic speed prediction method based on the spatial-temporal analysis of traffic flow and a combined deep-learning model, and a hybrid spatial-temporal feature selection algorithm (STFSA) of a convolutional neural network–gated recurrent unit (CNN-GRU)) is initially developed. Specifically, the STFSA is firstly employed to reconstruct the spatial-temporal matrix of traffic speed based on temporal continuity and spatial characteristics, and then this matrix is considered as the input feature of the prediction model. After this, the nonlinear fitting ability of the CNN is adopted to extract deep features from the convolutional and pooling layers for model training. Finally, by combining the timing and long-range dependence of the captured data with the forward GRU and the reverse GRU, the accuracy of the prediction result is further improved. The validity of the proposed model can be verified by comparing the prediction results with the actual traffic data. Accordingly, in the case study, the performance is compared with various benchmark methods under the same prediction scenario, verifying the superiority of the proposed model.

2 September 2020 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
CMChangxi Ma
Changxi Ma
CWChao Wang
Chao Wang
XXXuecai(Daniel) Xu
Xuecai(Daniel) Xu
Various customized bus route optimization methods based on certain conditions have been applied to the actual route optimization problems, but the actual operation process of customized buses mostly lies in an uncertain condition. In this paper, a three-stage hybrid coding method based on NSGA-II algorithm was proposed to deal with customized bus route optimization under uncertain condition. Firstly, with the objective of minimizing passenger travel time and customized bus carbon emission, a robust optimization model was constructed. Second, with the Bertsimas-Sim robust optimization theory, the robust peer-to-peer transformation was performed on the robust model with uncertain parameters. Finally, the practical issue including three customized bus parking lots and 20 boarding and alighting stations were solved to verify the rationality of the model and algorithm. Compared with the hybrid algorithm based on K-means and multi-objective genetic algorithm, this method reveals not only better solution results, but saves 42.11% of computing time. The results are of great value for exploring customized bus route optimization methods and improving the efficiency of customized bus operations.

1 January 2020 in Accident Analysis & Prevention
Verified
Journal Article
Closed access
QYQuan Yuan
Quan Yuan
XXXuecai(Daniel) Xu
Xuecai(Daniel) Xu
MXMingchang Xu
Mingchang Xu
JZJunwei Zhao
Junwei Zhao
YLYibing Li
Yibing Li

19 December 2019 in Sustainability
Verified
Journal Article
Open access
PDF file
LTLimin Tan
Limin Tan
CMChangxi Ma
Changxi Ma
XXXuecai(Daniel) Xu
Xuecai(Daniel) Xu
Jin XUJin XU
Jin XU
To understand the public’s acceptance of autonomous vehicles, studies were conducted from the perspectives of personal attributes, travel demand and cognitions of autonomous vehicles based on 403 valid questionnaires. Influencing factors of whether travelers are purchasing autonomous vehicles, whether travelers without a driver’s license intend to take a driver’s license in the future and whether travelers are choosing an autonomous private car if travelers can only take a taxi or drive a private car are analyzed by building Logistic regression models. The results show that personal monthly income, driver’s license, driving confidence, preference for autonomous vehicles and convenience of arriving at public transport stations will affect the purchase decision of autonomous vehicles; teenagers, long-distance travelers, students and employees of enterprises and institutions, those who believe that traditional taxis/taxi-hailing are unsafe, and those who lack confidence in driving have a higher probability of choosing autonomous vehicles. This research can be used to predict the probability of future purchase and use decisions for autonomous vehicles based on data from other populations.

21 July 2017 in PLOS ONE
Verified
Journal Article
Open access
PDF file
XXXuecai(Daniel) Xu
Xuecai(Daniel) Xu
SWS. C. Wong
S. C. Wong
FZFeng Zhu
Feng Zhu
XPXin Pei
Xin Pei
HHHelai Huang
Helai Huang
YLYoujun Liu
Youjun Liu
The objective of this paper is to provide a new method for estimating crash rate and severity simultaneously. This study explores a Heckman selection model of the crash rate and severity simultaneously at different levels and a two-step procedure is used to investigate the crash rate and severity levels. The first step uses a probit regression model to determine the sample selection process, and the second step develops a multiple regression model to simultaneously evaluate the crash rate and severity for slight injury/kill or serious injury (KSI), respectively. The model uses 555 observations from 262 signalized intersections in the Hong Kong metropolitan area, integrated with information on the traffic flow, geometric road design, road environment, traffic control and any crashes that occurred during two years. The results of the proposed two-step Heckman selection model illustrate the necessity of different crash rates for different crash severity levels. A comparison with the existing approaches suggests that the Heckman selection model offers an efficient and convenient alternative method for evaluating the safety performance at signalized intersections.