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Bus evacuation during no-notice disasters in downtown areas: A case study of the Zhongguancun area, Beijing

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Journal of Safety Science and Resilience 2022年第3期3卷 235-242页

作者： Xingang Li Xiaodan Cui Rui Jiang Bin Jia Key laboratory of Transport Industry of big data application technologies for comprehensive Transport Beijing Jiaotong UniversityBeijing 100044China

This paper focuses on the bus evacuation problem with pedestrians’short-distance walking ability between bus stations during no-notice disasters in downtown areas.A mixed-integer linear programming model is proposed to solve this *** objective function is to minimize the evacuation time and number of *** model obtains the flow of evacuees and buses on each arc to the route of buses in the process of ***,a real-time bus evacuation demand estimation method is proposed based on smart card ***,the example of Zhongguancun area in Beijing is used to verify the practicality and validity of the *** results show that pedestrian short-distance walking can effectively reduce casualties and improve the utilization rate of buses.

关键词： No-notice disaster Bus evacuation Short-distance walking Mixed integer linear programming

Electrochemical conversion of methane to bridge the gap in the artificial carbon cycle

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Journal of Energy Chemistry 2025年第1期100卷 286-308页

作者： Yuhao Peng Yuefeng Song Ihar Razanau Juanxiu Xiao Wei Xiao Di Hu Guoxiong Wang College of Chemistry and Molecular Sciences Hubei Key Laboratory of Electrochemical Power Sources Wuhan University State Key laboratory of Catalysis Dalian National Laboratory for Clean Energy iChEM (Collaborative Innovation Center of Chemistry for Energy Materials) Dalian Institute of Chemical Physics Chinese Academy of Sciences laboratory of Physical-Chemical technologies SSPA Scientific and Practical Materials Research Centre of NAS of Belarus State Key laboratory of Marine Resources Utilization in South China Sea Collaborative Innovation Center of Marine Science and Technology School of Marine Science and Engineering Hainan University Department of Chemical and Environmental engineering University of Nottingham Ningbo China

Methane, an abundant one-carbon（C1） resource, is extensively used in the industrial production of vital fuels and value-added chemicals. However, current industrial methane conversion technologies are energy-and carbon-intensive, mainly due to the high activation energy required to break the inert C–H bond, low selectivity, and problematic side reactions, including CO2emissions and coke deposition. Electrochemical conversion of methane（ECM） using intermittent renewable energy offers an attractive solution, due to its modular reactor design and operational flexibility across a broad spectrum of temperatures and pressures. This review emphasizes conversion pathways of methane in various reaction systems, highlighting the significance and advantages of ECM in facilitating a sustainable artificial carbon cycle. This work provides a comprehensive overview of conventional methane activation mechanisms and delineates the complete pathways of methane conversion in electrolysis contexts. Based on surface/interface chemistry, this work systematically analyzes proposed reaction pathways and corresponding strategies to enhance ECM efficiency towards various target products, including syngas, hydrocarbons, oxygenates, and advanced carbon materials. The discussion also encompasses opportunities and challenges for the ECM process, including insights into ECM pathways, rational electrocatalyst design, establishment of benchmarking protocols, electrolyte engineering, enhancement of CH4conversion rates, and minimization of CO2emission.

关键词： Methane Electrochemical conversion Reaction mechanism Catalyst design Electrode Electrocatalysis

Advancing Graph Convolution Network with Revised Laplacian Matrix

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Chinese Journal of Electronics 2020年第6期29卷 1134-1140页

作者： WANG Jiahui GUO Yi WANG Zhihong TANG Qifeng WEN Xinxiu East China University of Science and Technology national engineering laboratory for big data Distribution and Exchange technologies

Graph convolution networks are extremely efficient on the graph-structure data,which both consider the graph and feature *** existing models mainly focus on redefining the complicated network structure,while ignoring the negative impact of lowquality input data during the aggregation *** paper utilizes the revised Laplacian matrix to improve the performance of the original model in the preprocessing *** comprehensive experimental results testify that our proposed model performs significantly better than other off-the-shelf models with a lower computational complexity,which gains relatively higher accuracy and stability.

关键词： Laplacian matrix graph-structure data network structure convolutional neural nets feature information computational complexity data structures graph theory Algebra Computational complexity graph convolution network Neural computing techniques File organisation matrix algebra Combinatorial mathematics

Investigation into the Methodology and Implementation of Life Cycle engineering under China’s Carbon Reduction Target in the Process Industry

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engineering 2024年第9期40卷 87-99页

作者： Mingyang Li Feng Gao Zuoren Nie Boxue Sun Yu Liu Xianzheng Gong national engineering laboratory for Industrial big-data application Technology College of Material Science and EngineeringBeijing University of TechnologyBeijing 100124China

The industrial sector is the primary source of carbon emissions in *** pursuit of meeting its carbon reduction targets,China aims to promote resource consumption sustainability,reduce energy consumption,and achieve carbon neutrality within its processing *** effective strategy to promote energy savings and carbon reduction throughout the life cycle of materials is by applying life cycle engineering *** strategy aims to attain an optimal solution for material performance,resource consumption,and environmental *** this study,five types of technologies were considered:raw material replacement,process reengineering,fuel replacement,energy recycling and reutilization,and material recycling and *** meaning,methodology,and development status of life cycle engineering technology abroad and domestically are discussed in detail.A multidimensional analysis of ecological design was conducted from the perspectives of resource and energy consumption,carbon emissions,product performance,and recycling of secondary resources in a manufacturing *** coupled with an integrated method to analyze carbon emissions in the entire life cycle of a material process industry was applied to the nonferrous industry,as an *** results provide effective ideas and solutions for achieving low or zero carbon emission production in the Chinese industry as recycled aluminum and primary aluminum based on advanced technologies had reduced resource consumption and emissions as compared to primary aluminum production.

关键词： Carbon neutrality Life cycle engineering Process Industry Carbon reduction technology Eco-design

Policy Iteration for Optimal Control of Discrete-Time Time-Varying Nonlinear Systems

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IEEE/CAA Journal of Automatica Sinica 2023年第3期10卷 781-791页

作者： Guangyu Zhu Xiaolu Li Ranran Sun Yiyuan Yang Peng Zhang Beijing Research Center of Urban traffic Information Sensing and Service technologies Key laboratory of Transport Industry of big data application technologies for comprehensive Transport Beijing Jiaotong UniversityBeijing 100044China Transport Planning and Research Institute Ministry of TransportChinaBeijing 100028China

Aimed at infinite horizon optimal control problems of discrete time-varying nonlinear systems,in this paper,a new iterative adaptive dynamic programming algorithm,which is the discrete-time time-varying policy iteration(DTTV)algorithm,is *** iterative control law is designed to update the iterative value function which approximates the index function of optimal *** admissibility of the iterative control law is *** results show that the iterative value function is non-increasingly convergent to the Bellman-equation optimal *** implement the algorithm,neural networks are employed and a new implementation structure is established,which avoids solving the generalized Bellman equation in each ***,the optimal control laws for torsional pendulum and inverted pendulum systems are obtained by using the DTTV policy iteration algorithm,where the mass and pendulum bar length are permitted to be time-varying *** effectiveness of the developed method is illustrated by numerical results and comparisons.

关键词： Adaptive critic designs adaptive dynamic programming approximate dynamic programming optimal control policy iteration time-varying

A new heuristics model of simulating pedestrian dynamics based on Voronoi diagram

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Chinese Physics B 2021年第1期30卷 623-639页

作者： Xin-Sen Wu Hao Yue Qiu-Mei Liu Xu Zhang Chun-Fu Shao Key laboratory of Transport Industry of big data application technologies for comprehensive Transport Ministry of TransportBeijing Jiaotong UniversityBeijing 100044China College of Civil engineering and Architecture Henan University of TechnologyZhengzhou 450001China

A new heuristics model based on the Voronoi diagram is presented to simulate pedestrian dynamics with the noncrowded state, in which these mechanisms of preference demand evading and surpassing, microscopic anti-deadlock, and site-fine-tuning are considered. The preference demand describes the willingness determination of detouring or following other pedestrians. In the evading and surpassing mechanisms, in order to achieve a balance between avoiding conflicts and minimizing detour distances, a new pair of concepts: "allow-areas and denial-areas" are introduced to divide the feasible region for pedestrians detour behaviors, in which the direction and magnitude of detour velocity are determined.A microscopic anti-deadlock mechanism is inserted to avoid deadlock problem of the counter-directional pedestrian. A site-fine-tuning mechanism is introduced to describe the behavior of avoiding getting too close to the neighbors in pedestrian movement. The presented model is verified through multiple scenarios, including the uni-or bi-direction pedestrian flow in the corridor without obstacles, the uni-direction pedestrian flow in the corridor with obstacles, and the pedestrian evacuation from a room with single-exit. The simulation results show that the velocity–density relationship is consistent with empirical data. Some self-organizing phenomena, such as lanes formation and arching are observed in the *** pedestrians detour an obstacle, the avoiding area before the obstacle and the unoccupied area after the obstacle can be observed. When pedestrians evacuate through a bottleneck without panic, the fan-shaped crowd can be found, which is consistent with the actual observation. It is also found that the behavior of following others in an orderly manner is more conducive to the improvement of the overall movement efficiency when the crowd moves in a limited space.

关键词： pedestrian dynamics pedestrian simulation heuristics rules Voronoi diagram

Influence of bottleneck on single-file pedestrian flow:Findings from two experiments

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Chinese Physics B 2020年第8期29卷 564-571页

作者： Cheng-Jie Jin Rui Jiang Da-Wei Li Jiangsu Key laboratory of Urban ITS Southeast University of ChinaNanjing 210096China Jiangsu Province Collaborative Innovation Center of Modern Urban traffic technologies Nanjing 210096China Key laboratory of Transport Industry of big data application technologies for comprehensive Transport Ministry of TransportBeijing Jiaotong UniversityBeijing 100044China

In order to investigate the influence of bottleneck on single-file pedestrian flow,we conduct two different bottleneck *** first one is on ring road,while the second one is on straight *** the first one,the global density is always set to be 1.5 ped/*** corresponding critical flow rate for the bottleneck activation is about 0.57 ped/*** data of the detectors set at different locations,including the velocities and time-headways,show that the amplitude of the oscillation of the stop-and-go waves gradually increases during the upstream ***,when the measured flow rates are the same,the different situations in the single-file experiments with and without bottleneck are compared and *** the second one,lower flow rates are used and the bottleneck is always *** all the runs,the system can reach one stable state,and the time needed is nearly the *** the stable area,the statistics of pedestrians'velocities keeps nearly constant in both time and *** this area,when the waiting time is not long(X=10 s),the phenomenon observed is similar to that found on ring road,e.g.,the statistics of pedestrians'velocities also gradually increases during the upstream *** phenomenon is similar to that found in vehicular traffic flow,which shows the universality of different traffic *** when the waiting time becomes longer(X=20 s),this situation will be broken since the actions of many pedestrians become much *** these results can facilitate understanding more about the influence of bottleneck on single-file pedestrian flow.

关键词： pedestrian flow single-file flow experiment bottleneck stop-and-go

Impact of connected and autonomous vehicles on traffic safety of mixed traffic flow:from the perspective of connectivity and spatial distribution

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Transportation Safety and Environment 2022年第3期4卷 88-97页

作者： Jiakuan Dong Jiangfeng Wang Dongyu Luo Key laboratory of Transport Industry of big data application technologies for comprehensive Transport of Ministry of Transport Beijing Jiaotong UniversityBeijing 100044China.

Equipped with high driving automation and advanced communication technologies, connected and autonomous vehicles (CAV) areexpected to possess a shorter reaction time and a wider vision,which are promising to improve traffic safety and efficiency. However,little attention has been paid to the effect of connectivity and spatial distribution on the safety performance of mixed traffic flow. Inthis paper, we attempt to investigate the impact of CAV on traffic safety considering these factors. To this end, a car-following modelfor CAV is proposed first. Then, the cooperative driving strategy for CAVs is designed. Precisely, the feedback gains of the informationare adjusted in real-time and are designed based on the derived stability criterion of the mixed traffic flow. Microscopic simulations ofmixed traffic flow in traffic oscillation are designed and conducted to explore how the distribution and connectivity of CAV affect thesafety performance ofmixed traffic flow. Simulation results show that increasing the penetration rate of CAV is promising to shift thesafety performance ofmixed traffic flow. In addition, the safety performance of mixed traffic flow is related to the spatial distributionand communication range of CAV. Besides, increasing communication range does not inevitably improve the safety performance ofmixed traffic flow when the penetration rate of CAV is low. Moreover, it is also found from the spatial–temporal trajectory of themixedtraffic flow that introducing CAV can mitigate the propagation of the stop-and-go wave and increase the throughput.

关键词： Mixed traffic traffic safety connected and autonomous vehicle connectivity spatial distribution

Optimal operating strategy of short turning lines for the battery electric bus system

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Communications in Transportation Research 2021年第1期1卷 193-204页

作者： Wenwei Zhang Hui Zhao Min Xu Department of Industrial and Systems engineering The Hong Kong Polytechnic UniversityHung HomHong KongChina MOT Key laboratory of Transport Industry of big data application technologies for comprehensive Transport School of Traffic and TransportationBeijing Jiaotong UniversityBeijing100044China

Operating short turning line is an efficient strategy to satisfy the unevenly distributed demand during peak periods while reducing operational ***,for the battery electric bus(BEB)system,the application of the strategy is challenging due to the disadvantages of BEBs,such as limited driving mileage and long charging *** vehicle configuration and charging scheduling may dramatically increase the operational cost and cut the benefits of these *** this work,we propose a general framework to design an effective short turning strategy for the BEB system at a tactical planning ***,the trade-off relationship between the battery capacity and the average trip time is identified by modeling the BEBs ***,a microeconomic model is formulated to jointly optimize the frequencies and charging schedules of the whole bus line and the short turning line,to effectively minimize passengers’waiting time and operational ***,numerical experiments have been carried out for an illustrative linear line to demonstrate the potential benefits of the sub-line operating strategy compared with the normal operation.

关键词： Battery electric bus Short turning line Microeconomic model Charging station