Juan Zhang

Dr. Juan Zhang

University of Exeter, Exeter, Devon, UK
+1
orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

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

Representative Publications

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28 April 2021 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
PWPangwei Wang
Pangwei Wang
HDHui Deng
Hui Deng
JZJuan Zhang
Juan Zhang
LWLi Wang
Li Wang
MZMingfang Zhang
Mingfang Zhang
YLYongfu Li
Yongfu Li
Vehicular platoon control can effectively achieve group consensus, improve vehicular running safety and increase road capacity. However, some constraints exist in practical situations due to the limitations of traffic environment in time-varying metrics (time-delay, packet-dropout or interruption) in wireless communication systems. In this work, a distributed model predictive control (MPC) algorithm is proposed for connected vehicle platoon with a focus on switching communication topologies and control strategy under abnormal communications. Firstly, the predecessor-leader following is selected as the basic communication topology, by which the switching communication topology and the desired vehicle spacing policy are established. Secondly, the platoon control algorithm of connected vehicles is established and a set of constraints is analyzed. Thirdly, the ${\mathcal{ L}}_{2} $ -norm string stability criterion and the asymptotic stability criterion are considered within the proposed MPC. Finally, a co-simulation platform for connected vehicle platoon is developed based on Prescan/Matlab/V2X communication simulator. In addition, the platoon control algorithm is tested in three traffic scenarios including normal communication, leading vehicle with abnormal communication and following vehicle with abnormal communication. The experiments demonstrate that the communication topologies in different communication environments can be switched well in real time through the proposed platoon control algorithm. In addition, the string stability, the consistency of vehicle spacing, speed and acceleration are proven to be guaranteed simultaneously.

16 January 2024 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
JZJuan Zhang
Juan Zhang
YWYulei Wu
Yulei Wu
Geyong  MinGeyong Min
Geyong Min
Keqin LiKeqin Li
Keqin Li
With the unprecedented scalability issues rising in vehicular edge computing (VEC), we argue in this paper that the scalability, along with the remarkable growth of demands for offloading, should be integrated into the modelling for effective offloading decision-making strategies requested by a large number of vehicles. A two-stage game-theory model can depict offloading decision-making strategies by considering both the revenue of network operators and the cost of VEC users. However, heuristic processes of solving such models show significant limitations in terms of high computational complexity and energy consumption due to the changing VEC environment. Therefore, our objective in this study is to solve the game-theory model efficiently and achieve scalable offloading for the changing VEC environment. We first develop a two-stage game-theory model for the offloading decision-making strategy for VEC, by which an operator’s revenue, energy consumption and latency are considered. Then a neural network (NN) model is designed to learn the predicted behaviours of the established game-theory model for offloading decisions in a more efficient manner. After that, a feature-based transfer learning algorithm is proposed for scalable offloading optimization under unseen VEC environments. Experimental results show that the proposed NN can significantly improve the efficiency of solving the game theory model, and the developed transfer learning approach can effectively achieve the scalability of offloading decisions in a changing VEC environment. The results demonstrate that the accuracy of the proposed transfer learning approach is 37% higher than that of several state-of-the-art algorithms, and the runtime halves.

29 April 2022 in Applied Sciences
Verified
Journal Article
Open access
PDF file
PWPangwei Wang
Pangwei Wang
RYRongsheng Ye
Rongsheng Ye
JZJuan Zhang
Juan Zhang
TWTianren Wang
Tianren Wang
The rapid increase in the number of vehicles has brought significant challenges to energy conservation and environmental sustainability. To solve these problems, various frameworks and models based on intelligent connected vehicles (ICVs) have been identified for road capacity improvement and fuel consumption reduction. In this paper, an eco-driving controller with ICVs was first proposed by combining vehicular dynamics with wireless communication technologies, where the nodes that can implement perception and control in a simulated complex traffic environment have been deployed. Then, the information of the surrounding environment, including the preceding vehicles, was obtained through a wireless communication module based on the technology of vehicle to everything (V2X). Besides, the advanced model predictive control (MPC) strategy was integrated into the ICV controller with the objectives of minimizing the driving spacing and improving environmental sustainability. Finally, a co-simulation platform for ICVs based on a robot operating system (ROS) and PreScan software was constructed, and the dynamic characteristics of the controller were verified in three aspects, including car-following behaviors, fuel efficiency improvement, and carbon dioxide emission reduction. The proposed controller showed that it can reduce fuel consumption by 3.71% and reduce carbon dioxide emissions by 3.42%, in the scenarios of a preceding vehicle with constant velocity, and by 6.77% and 7.91%, respectively, in a preceding vehicle with variable velocity scenario. The demonstrated experimental results show that the proposed controller can effectively reduce fuel consumption and emissions during car-following.

19 December 2023 in IEEE Transactions on Intelligent Transportation Systems
Verified
Journal Article
Closed access
PWPangwei Wang
Pangwei Wang
CLCheng Liu
Cheng Liu
JZJuan Zhang
Juan Zhang
LWLi Wang
Li Wang
MZMingfang Zhang
Mingfang Zhang
In order to locate the position of intelligent connected vehicles (ICVs) robustly in urban intersection scenarios, a novel compound positioning method based on the Dempster-Shafer evidence theory and the improved multi-layer unscented Kalman filter (DS-UKF) is proposed in this paper. The Euclidean distance between the heterogeneous data is used to optimize the Dempster-Shafer (D-S) evidence theory, so that the position of ICVs and the distance between ICVs and roadside positioning platform with higher confidence can be obtained. Meanwhile, considering the high complication of urban intersections, the unscented Kalman filter (UKF) algorithm is improved based on the covariance of error sequences so that the influences caused by observation noise anomalies can be reduced. To further improve the accuracy of positional prediction, the position of roadside positioning platform is extended dimensionally into the state vector of ICVs to observe the distance between ICVs and roadside positioning platform. Then the particle filter (PF) theory is introduced to integrate the upper-layer with the lower-layer UKF to reduce the positioning errors brought by signal interferences. Besides, an adaptive factor is adopted to connect D-S theory with the improved multi-layer UKF (IUKF) to dynamically update the weights of output values from sensors. Furthermore, a communication mechanism between the ICVs platform and the roadside positioning platform is established in this project with considering the reliability and low latency of vehicle to everything (V2X) communications. Finally, the feasibility and superiority of the proposed method is validated by experiments with three ICVs at an urban intersection. The experimental results have shown that the proposed method can locate the position of ICVs rapidly and stably in urban intersections and has better positioning performance compared to the current state-of-the-art algorithms.

15 December 2020 in Journal of Advanced Transportation
Verified
Journal Article
Open access
PDF file
PWPangwei Wang
Pangwei Wang
YWYunfeng Wang
Yunfeng Wang
HDHui Deng
Hui Deng
MZMingfang Zhang
Mingfang Zhang
JZJuan Zhang
Juan Zhang
It is agreed that connected vehicle technologies have broad implications to traffic management systems. In order to alleviate urban congestion and improve road capacity, this paper proposes a multilane spatiotemporal trajectory optimization method (MSTTOM) to reach full potential of connected vehicles by considering vehicular safety, traffic capacity, fuel efficiency, and driver comfort. In this MSTTOM, the dynamic characteristics of connected vehicles, the vehicular state vector, the optimized objective function, and the constraints are formulated. The method for solving the trajectory problem is optimized based on Pontryagin’s maximum principle and reinforcement learning (RL). A typical scenario of intersection with a one-way 4-lane section is measured, and the data within 24 hours are collected for tests. The results demonstrate that the proposed method can optimize the traffic flow by enhancing vehicle fuel efficiency by 32% and reducing pollutants emissions by 17% compared with the advanced glidepath prototype application (GPPA) scheme.

11 December 2024 in IEEE Transactions on Network Science and Engineering
Verified
Journal Article
Closed access
JRJeffrey Redondo
Jeffrey Redondo
Nauman AslamNauman Aslam
Nauman Aslam
JZJuan Zhang
Juan Zhang
ZYZhenhui Yuan
Zhenhui Yuan
Reinforcement Learning (RL) algorithms have been increasingly applied to tackle the complex challenges of offloading in vehicular ad hoc networks (VANETs), particularly in high-density and high-mobility scenarios where network congestion leads to significant latency issues. These challenges are further exacerbated by the introduction of low-latency applications, such as high-definition (HD) Maps, which are compromised in the current IEEE 802.11p standard due to their low-priority classification. In our previous work, we developed a novel coverage-aware Q-learning algorithm using a single-agent approach to address these concerns. However, a key question remains: how does this solution perform when scaled to a larger, more complex environment using a multi-agent system? To address this, our current study evaluates the scalability and effectiveness of the previously developed single-agent Q-learning solution within a distributed multi-agent environment. This multi-agent approach is designed to enhance network performance by leveraging a smaller state and action space across multiple agents. We conduct extensive evaluations through various test cases, considering factors such as reward functions for individual and overall network performance, the number of agents, and comparisons between centralized and distributed learning. The experimental results show that our proposed multi-agent solution significantly reduces time latency in voice, video, HD Map, and best-effort cases by 40.4%, 36%, 43%, and 12%, respectively, compared to the single-agent approach. These findings demonstrate the potential of our solution to effectively manage the challenges of VANETs in dynamic and large-scale environments.