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1 – 10 of 66Yong Chen, Zhixian Zhan and Wei Zhang
As the strategy of 5G new infrastructure is deployed and advanced, 5G-R becomes the primary technical system for future mobile communication of China’s railway. V2V communication…
Abstract
Purpose
As the strategy of 5G new infrastructure is deployed and advanced, 5G-R becomes the primary technical system for future mobile communication of China’s railway. V2V communication is also an important application scenario of 5G communication systems on high-speed railways, so time synchronization between vehicles is critical for train control systems to be real-time and safe. How to improve the time synchronization performance in V2V communication is crucial to ensure the operational safety and efficiency of high-speed railways.
Design/methodology/approach
This paper proposed a time synchronization method based on model predictive control (MPC) for V2V communication. Firstly, a synchronous clock for V2V communication was modeled based on the fifth generation mobile communication-railway (5G-R) system. Secondly, an observation equation was introduced according to the phase and frequency offsets between synchronous clocks of two adjacent vehicles to construct an MPC-based space model of clock states of the adjacent vehicles. Finally, the optimal clock offset was solved through multistep prediction, rolling optimization and other control methods, and time synchronization in different V2V communication scenarios based on the 5G-R system was realized through negative feedback correction.
Findings
The results of simulation tests conducted with and without a repeater, respectively, show that the proposed method can realize time synchronization of V2V communication in both scenarios. Compared with other methods, the proposed method has faster convergence speed and higher synchronization precision regardless of whether there is a repeater or not.
Originality/value
This paper proposed an MPC-based time synchronization method for V2V communication under 5G-R. Through the construction of MPC controllers for clocks of adjacent vehicles, time synchronization was realized for V2V communication under 5G-R by using control means such as multistep prediction, rolling optimization, and feedback correction. In view of the problems of low synchronization precision and slow convergence speed caused by packet loss with existing synchronization methods, the observer equation was introduced to estimate the clock state of the adjacent vehicles in case of packet loss, which reduces the impact of clock error caused by packet loss in the synchronization process and improves the synchronization precision of V2V communication. The research results provide some theoretical references for V2V synchronous wireless communication under 5G-R technology.
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Cong Li, YunFeng Xie, Gang Wang, XianFeng Zeng and Hui Jing
This paper studies the lateral stability regulation of intelligent electric vehicle (EV) based on model predictive control (MPC) algorithm.
Abstract
Purpose
This paper studies the lateral stability regulation of intelligent electric vehicle (EV) based on model predictive control (MPC) algorithm.
Design/methodology/approach
Firstly, the bicycle model is adopted in the system modelling process. To improve the accuracy, the lateral stiffness of front and rear tire is estimated using the real-time yaw rate acceleration and lateral acceleration of the vehicle based on the vehicle dynamics. Then the constraint of input and output in the model predictive controller is designed. Soft constraints on the lateral speed of the vehicle are designed to guarantee the solved persistent feasibility and enforce the vehicle’s sideslip angle within a safety range.
Findings
The simulation results show that the proposed lateral stability controller based on the MPC algorithm can improve the handling and stability performance of the vehicle under complex working conditions.
Originality/value
The MPC schema and the objective function are established. The integrated active front steering/direct yaw moments control strategy is simultaneously adopted in the model. The vehicle’s sideslip angle is chosen as the constraint and is controlled in stable range. The online estimation of tire stiffness is performed. The vehicle’s lateral acceleration and the yaw rate acceleration are modelled into the two-degree-of-freedom equation to solve the tire cornering stiffness in real time. This can ensure the accuracy of model.
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Yunfei Li, Shengbo Eben Li, Xingheng Jia, Shulin Zeng and Yu Wang
The purpose of this paper is to reduce the difficulty of model predictive control (MPC) deployment on FPGA so that researchers can make better use of FPGA technology for academic…
Abstract
Purpose
The purpose of this paper is to reduce the difficulty of model predictive control (MPC) deployment on FPGA so that researchers can make better use of FPGA technology for academic research.
Design/methodology/approach
In this paper, the MPC algorithm is written into FPGA by combining hardware with software. Experiments have verified this method.
Findings
This paper implements a ZYNQ-based design method, which could significantly reduce the difficulty of development. The comparison with the CPU solution results proves that FPGA has a significant acceleration effect on the solution of MPC through the method.
Research limitations implications
Due to the limitation of practical conditions, this paper cannot carry out a hardware-in-the-loop experiment for the time being, instead of an open-loop experiment.
Originality value
This paper proposes a new design method to deploy the MPC algorithm to the FPGA, reducing the development difficulty of the algorithm implementation on FPGA. It greatly facilitates researchers in the field of autonomous driving to carry out FPGA algorithm hardware acceleration research.
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Abstract
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Mohammed S. Al-kahtani, Lutful Karim and Nargis Khan
Designing an efficient routing protocol that opportunistically forwards data to the destination node through nearby sensor nodes or devices is significantly important for an…
Abstract
Designing an efficient routing protocol that opportunistically forwards data to the destination node through nearby sensor nodes or devices is significantly important for an effective incidence response and disaster recovery framework. Existing sensor routing protocols are mostly not effective in such disaster recovery applications as the networks are affected (destroyed or overused) in disasters such as earthquake, flood, Tsunami and wildfire. These protocols require a large number of message transmissions to reestablish the clusters and communications that is not energy efficient and result in packet loss. This paper introduces ODCR - an energy efficient and reliable opportunistic density clustered-based routing protocol for such emergency sensor applications. We perform simulation to measure the performance of ODCR protocol in terms of network energy consumptions, throughput and packet loss ratio. Simulation results demonstrate that the ODCR protocol is much better than the existing TEEN, LEACH and LORA protocols in term of these performance metrics.
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Son Nghiem and Xuan-Binh (Benjamin) Vu
Basic income (BI) is predicted to be the major economic intervention in response to raising income inequality and accelerating technological progress. Financing is often the first…
Abstract
Purpose
Basic income (BI) is predicted to be the major economic intervention in response to raising income inequality and accelerating technological progress. Financing is often the first question that arises when discussing a BI. A thorough answer to this question will determine the sustainability of any BI program. However, BI experiments implemented worldwide have not answered this question. This paper explores two options for a BI program in Australia: (1) BI and (2) top-up basic income (TBI).
Design/methodology/approach
The authors employ “back-of-the-envelope” calculations with the latest publicly available data on income distribution, the poverty line and the share of income tax in the government revenue to estimate the costs of implementing BI in Australia.
Findings
Even without any change in the current tax regulations, the TBI option, which requires a contribution of 2–3% disposable income from net contributors, will guarantee that no Australian family lives under the current national poverty line. The BI for all options is not financially feasible under the current tax and transfer regulations because it requires an additional tax rate of at least 42% of disposable income from net contributors.
Practical implications
The results of this study can serve as inputs for the design and implementation of BI options in Australia and similar countries.
Originality/value
This is the first paper that examines the macroeconomic effects of BI options in Australia.
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Wei Xue, Rencheng Zheng, Bo Yang, Zheng Wang, Tsutomu Kaizuka and Kimihiko Nakano
Automated driving systems (ADSs) are being developed to avoid human error and improve driving safety. However, limited focus has been given to the fallback behavior of automated…
Abstract
Purpose
Automated driving systems (ADSs) are being developed to avoid human error and improve driving safety. However, limited focus has been given to the fallback behavior of automated vehicles, which act as a fail-safe mechanism to deal with safety issues resulting from sensor failure. Therefore, this study aims to establish a fallback control approach aimed at driving an automated vehicle to a safe parking lane under perceptive sensor malfunction.
Design/methodology/approach
Owing to an undetected area resulting from a front sensor malfunction, the proposed ADS first creates virtual vehicles to replace existing vehicles in the undetected area. Afterward, the virtual vehicles are assumed to perform the most hazardous driving behavior toward the host vehicle; an adaptive model predictive control algorithm is then presented to optimize the control task during the fallback procedure, avoiding potential collisions with surrounding vehicles. This fallback approach was tested in typical cases related to car-following and lane changes.
Findings
It is confirmed that the host vehicle avoid collision with the surrounding vehicles during the fallback procedure, revealing that the proposed method is effective for the test scenarios.
Originality/value
This study presents a model for the path-planning problem regarding an automated vehicle under perceptive sensor failure, and it proposes an original path-planning approach based on virtual vehicle scheme to improve the safety of an automated vehicle during a fallback procedure. This proposal gives a different view on the fallback safety problem from the normal strategy, in which the mode is switched to manual if a driver is available or the vehicle is instantly stopped.
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Liwei Xu, Guodong Yin, Guangmin Li, Athar Hanif and Chentong Bian
The purpose of this paper is to investigate problems in performing stable lane changes and to find a solution to reduce energy consumption of autonomous electric vehicles.
Abstract
Purpose
The purpose of this paper is to investigate problems in performing stable lane changes and to find a solution to reduce energy consumption of autonomous electric vehicles.
Design/methodology/approach
An optimization algorithm, model predictive control (MPC) and Karush–Kuhn–Tucker (KKT) conditions are adopted to resolve the problems of obtaining optimal lane time, tracking dynamic reference and energy-efficient allocation. In this paper, the dynamic constraints of vehicles during lane change are first established based on the longitudinal and lateral force coupling characteristics and the nominal reference trajectory. Then, by optimizing the lane change time, the yaw rate and lateral acceleration that connect with the lane change time are limed. Furthermore, to assure the dynamic properties of autonomous vehicles, the real system inputs under the restraints are obtained by using the MPC method. Based on the gained inputs and the efficient map of brushless direct-current in-wheel motors (BLDC IWMs), the nonlinear cost function which combines vehicle dynamic and energy consumption is given and the KKT-based method is adopted.
Findings
The effectiveness of the proposed control system is verified by numerical simulations. Consequently, the proposed control system can successfully achieve stable trajectory planning, which means that the yaw rate and longitudinal and lateral acceleration of vehicle are within stability boundaries, which accomplishes accurate tracking control and decreases obvious energy consumption.
Originality/value
This paper proposes a solution to simultaneously satisfy stable lane change maneuvering and reduction of energy consumption for autonomous electric vehicles. Different from previous path planning researches in which only the geometric constraints are involved, this paper considers vehicle dynamics, and stability boundaries are established in path planning to ensure the feasibility of the generated reference path.
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In response to the pandemic, the Korean government introduced fiscal measures: including the Emergency Disaster Relief Funds which is the first-ever universal benefit in Korea…
Abstract
Purpose
In response to the pandemic, the Korean government introduced fiscal measures: including the Emergency Disaster Relief Funds which is the first-ever universal benefit in Korea. This paper identifies the effects of the measures on poverty, household income and household consumption expenditure under the disproportionate effect of the pandemic.
Design/methodology/approach
This study analysed the Korea Household Income and Expenditure Survey (KHIES) with Changes-in-Changes at five percentiles (5, 25, 50, 75 and 95%) instead of Difference-in-Differences (DD) because the parallel trends assumption of DD cannot be investigated due to the recent KHIES redesign. In addition, it also exmined the effects on vulnerable groups (e.g. female, elderly and young households).
Findings
COVID-19 has had prompt and disproportionate effects on the vulnerable, such as low-income, female and elderly households. However, the government measures had a limited effect. First, the measures could not mitigate the initial income reduction and only had temporary positive effects on income and consumption expenditure. Second, young households tended to save the relief instead of present consumption. Lastly, education disparity was observed at 25 and 50%. Therefore, this study suggests that response measures need to be sustainable and concentrated on the vulnerable.
Originality/value
A large literature estimated effects on either household income or household consumption expenditure, and focused on macroeconomic indices (e.g. marginal propensity to consumption). This study analysed both income (poverty) and consumption expenditure and found policy implications for better welfare system in an economic downturn.
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Spam emails classification using data mining and machine learning approaches has enticed the researchers' attention duo to its obvious positive impact in protecting internet…
Abstract
Spam emails classification using data mining and machine learning approaches has enticed the researchers' attention duo to its obvious positive impact in protecting internet users. Several features can be used for creating data mining and machine learning based spam classification models. Yet, spammers know that the longer they will use the same set of features for tricking email users the more probably the anti-spam parties might develop tools for combating this kind of annoying email messages. Spammers, so, adapt by continuously reforming the group of features utilized for composing spam emails. For that reason, even though traditional classification methods possess sound classification results, they were ineffective for lifelong classification of spam emails duo to the fact that they might be prone to the so-called “Concept Drift”. In the current study, an enhanced model is proposed for ensuring lifelong spam classification model. For the evaluation purposes, the overall performance of the suggested model is contrasted against various other stream mining classification techniques. The results proved the success of the suggested model as a lifelong spam emails classification method.
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