交通运输工程学报

Cover and Contents of Vol.23, No.5, 2023

Cover Contents

Review on research of global major disaster event related port and shipping operation and management

YANG Zhong-zhen, YANG Yun-qian, XIN Xu

Abstract: To systematically sort out the research progress in the field of port and shipping operation and management after the global major disaster event, a total of 577 pieces of global major disaster events-related literature in the field of port and shipping management were analyzed by co-word clustering analysis using the knowledge graph analysis software VOSviewer included in Web of Science database and China National Knowledge Infrastructure (CNKI) database. Three research hotspots, including the shipping market, port and shipping operation and management, and port and shipping disaster prevention and control, were sorted out. The research objects, methods, and conclusions of the representative literatures concerning the abovementioned research hotspots were reviewed. The current research status and research gaps of port and shipping operation and management in the context of global major disaster events were analyzed. Several potential research directions were proposed. Research results show that the studies on the shipping market in the context of global major disaster events are mainly related to the freight market, including the market supply and demand relationship, freight rate forecast, and design of transaction mechanisms between stakeholders considering risks. The studies on the port operation and management include the port operation performance assessment, port governance and business model, and sustainable development of ports. The studies on the shipping operation and management focus on changes in the shipping network patterns, shipping network design, and shipping service sales strategy. The studies on the port and shipping disaster prevention and control focus on the topics such as the seafarer stress, health management, and psychological intervention. Future research directions include the prediction of market quotations using the machine learning and big data, the game behavior of port and shipping stakeholders considering the market risk factors, realization of intelligent port and shipping operation and management by applying the blockchain, artificial intelligence, big data, 5G, digital twin, and other emerging technologies, as well as construction of collaborative governance mechanism of global ports and shipping enterprises. They also include the liner alliance shipping network design, profit allocation mechanism for alliance members, and discussion on the seafarer shift system, daily health management theory, psychological identification, and intervention method in the context of global major disaster event.More>

2023, 23(5): 1-18. doi: 10.19818/j.cnki.1671-1637.2023.05.001

FullText HTML (491) PDF (6111KB) (222)

Review on research of road traffic safety of connected and automated vehicles

GUO Yan-yong, LIU Pei, YUAN Quan, LIU Pan, XU Jin, ZHANG Hui

Abstract: To comprehensively understand the research progress in the field of traffic safety concerning connected and automated vehicles (CAVs), a bibliometric method was used to retrieve key words, such as connected and automated (autonomous) vehicles, connected (autonomous) vehicles, and traffic safety (accident, crash, collision, conflict) through the Web of Science core database. A total of 2 130 relevant publications spanning from 2010 to 2021 were retrieved. These publications encompassed contributions from 5 474 authors and addressed 7 017 key words. A map of scientific knowledge was employed to analyze, summarize, and visual elucidate the developmental trajectory, research affiliations, research themes and contents, and research focal points of investigations in the realm of road traffic safety for CAVs. By scrutinizing the research themes and focal points, forthcoming research directions were delineated. Analysis results show that the study of road traffic safety for CAVs has undergone stages of inception, gradual progression, and rapid expansion. Presently, the United States and China are the foremost contributors to research on the road traffic safety for CAVs. Research themes primarily focus on the macro and micro traffic flow, traffic system impacts (travel, traffic environment, and traffic safety), vehicle safety and obstacle avoidance, route planning, and traffic safety assessment. Research focal points encompass the CAV traffic control, system optimization, new hybrid traffic flow safety analysis, micro-behavior modeling, and simulation-based safety evaluation. Future research should pivot towards a transition from the single-vehicle safety to the traffic flow accident risk propagation. This shift calls for breakthroughs in intelligent connected fleet decision-making and formation control technology. Additionally, there is a need to establish a virtual reality-based intelligent connected data-driven simulation environment, coupled with an in-depth testing platform. These advancements will facilitate an assessment system of driver takeover performance in the context of CAV man-machine co-driving scenarios. Ultimately, this will enable a refined analysis on the accident risk causation, traffic safety modeling and assessment, as well as the development of strategies and algorithms for the accident risk prevention and control.More>

2023, 23(5): 19-38. doi: 10.19818/j.cnki.1671-1637.2023.05.002

FullText HTML (2428) PDF (11888KB) (463)

Review on application of graph neural network in traffic prediction

HU Zuo-an, DENG Jin-cheng, HAN Jin-li, YUAN Kai

Abstract: To seek effective ways to improve the performance of spatial-temporal computing tasks in traffic prediction, and explore the prospects and challenges of applying the graph neural network technology in traffic prediction, the development of traffic prediction methods was reviewed. The advantages and limitations of model-driven methods, statistical models, traditional machine learning methods, and deep learning methods were summarized. The compatibility between graph networks and traffic networks was explained. The methods for constructing graphs were summarized. The data used for traffic prediction were classified. The commonalities and differences between different traffic prediction tasks were analyzed. The graph neural network models commonly used for traffic prediction tasks were concluded, including the convolutional graph neural network, graph attention network, graph autoencoder, and graph spatial-temporal network. The main factors and spatial-temporal modules considered when the graph neural network model was applied to traffic prediction were analyzed. The performance of various traffic speed prediction methods was compared. The impacts of different components of the graph neural network framework on the prediction performance were analyzed. The challenges and opportunities faced by traffic prediction based on the graph neural network were discussed from multiple perspectives such as the data multi-sourcing, application diversity, multimodality, dynamicity, model interpretability, uncertainty, and small sample learning. Relevant suggestions for the development trend of graph neural network were proposed. Research results show that compared with the benchmark model that only considers the time correlation, the performance of the prediction method based on the graph neural network improves significantly. The multi-mode time correlation, spatial-temporal attention mechanism, edge features, and external data can all significantly affect the prediction performance. The graph neural network provides a powerful means for modeling the spatial-temporal correlation with complex dynamicity of traffic networks. Currently, diversified models have been developed for the traffic state prediction problems. Future research can focus on developing efficient and dynamic spatial-temporal module integration architectures, designing modules that effectively integrate external data, expanding diversified application tasks, realizing the multi-mode traffic synchronous prediction, and developing efficient, reliable, and easy-to-explain models to achieve a balanced improvement in prediction accuracy and efficiency, so as to develop higher-level intelligent traffic.More>

2023, 23(5): 39-61. doi: 10.19818/j.cnki.1671-1637.2023.05.003

FullText HTML (382) PDF (7778KB) (521)

Review on research of crowdsourcing delivery

ZHAO Jian-you, LI Yue, TIAN Hao, TAO Xu-qiu, HOU Xue

Abstract: Based on 1 495 literatures collected in the SCI database and CNKI database, the knowledge graph analysis software VOSviewer was used to perform the clustering analysis of the co-occurrence terms of crowdsourcing delivery. The influencing factors related to the participants engaged in crowdsourcing delivery, the operations of crowdsourcing delivery platforms, and the routes of crowdsourcing delivery vehicles were systematically reviewed. The present situation of crowdsourcing delivery in China and abroad was analyzed, the existing problems of crowdsourcing delivery were discussed, and the future development directions of crowdsourcing delivery were put forward. Research results show that in terms of participants in crowdsourcing delivery, price, safety, and delivery difficulty are important factors affecting the popularity of crowdsourcing delivery model. In terms of platform operation, the existing crowdsourcing delivery operation platforms take the minimum cost or shortest path as the goal to build a single task matching function. In terms of vehicle routing problem, the existing crowdsourcing delivery mostly relies on the existing databases to solve the vehicle routing problem with a heuristic algorithm. The future development trend of crowdsourcing delivery research mainly lies in studying the influencing factors of crowdsourcing participants, reasonably adjusting the delivery prices, and refining the scenario to attract participants with different characteristics and adapt to regional customer density and economic development level differences. In addition, in order to improve the service level and competitiveness of crowdsourcing delivery platform, the factors, such as safety, resources, environment, and transportation, should be incorporated into the delivery platform to build a multi-objective task matching function. In order to adapt to the characteristics of crowdsourcing delivery and improve the response speed of crowdsourcing delivery system, a multi-objective path optimization function with priority should be constructed. Artificial intelligence algorithms and other tools should be used to optimize the problem of crowdsourcing delivery routes.More>

2023, 23(5): 62-84. doi: 10.19818/j.cnki.1671-1637.2023.05.004

FullText HTML (583) PDF (12208KB) (140)

Review on research of containership stowage planning of container terminals

CHANG Yi-mei

Abstract: Chinese and foreign literatures on the containership stowage planning problem of container terminals was summarized. The research situations and results of stowage planning were reviewed from three aspects, including classification, influencing factors, and solution methods. The shortcomings in current research and future research directions were explored. Analysis results show that there are fewer and fewer literatures those directly point out master bay planning problems and slot allocation problems in the titles, and more of them directly point out stowage planning problem. Most literatures consider several influencing factors of stowage planning problem, such as the containership stability and strength, container properties (size, weight, type, etc.), and quay crane properties. Few literatures consider all the influencing factors of stowage planning problem. Therefore, in order to make the research more closely related to the actual operations in container terminals, comprehensive consideration of the influencing factors of stowage planning problem will be future key research. The stowage planning is also influenced by other operations in container terminals. Hence, in order to improve the operation efficiency and level of the container terminals, the interaction among various regions of container terminals should be comprehensively considered. With the development of rail-water intermodal transportation, railway containers will also be loaded onto the containerships, so the railway containers also need to be considered in the stowage planning problem. Intelligent algorithms are designed in most literatures, and better optimal solutions are gained. However, to display the solution results more intuitively and vividly, simulation optimization and algorithm calculation should be combined.More>

2023, 23(5): 85-103. doi: 10.19818/j.cnki.1671-1637.2023.05.005

FullText HTML (397) PDF (2754KB) (102)

Anti-seismic performance of cast-in-place ECC and prefabricated mortise-tenon hybrid connection assembled RC bridge piers

LIN Shang-shun, LIN Yong-jie, XIA Zhang-hua, ZHAO Jin-bing, LI Ya-le

Abstract: In order to improve the anti-seismic performance of assembled reinforced concrete (RC) bridge piers, a new connection configuration using a hybrid connection of cast-in-place engineered cementitious composites (ECC) and prefabricated mortise-tenon was proposed. Quasi-static tests of three assembled RC pier specimens using hybrid connections (with the height of cast-in-place ECC segments and depth of the notch as the varying parameters, No. DZ-1, AC-200, and XJ-250) and one assembled RC pier specimen using a cast-in-place ECC wet connection (No. PT-1) were carried out. A test validated ABAQUS finite element model was established, and the effects of parameters such as the axial compression ratio, length-to-slender ratio, depth of notch, and height of cast-in-place ECC segments on the anti-seismic performance of assembled RC bridge piers were analyzed. Analysis results show that the damage modes of the four pier specimens are all compression bending damage, and the cast-in-place ECC segments of each specimen are not damaged. Compared with the PT-1 specimen, the peak loads of assembled RC bridge piers with cast-in-place ECC and prefabricated mortise-tenon hybrid connection increase by 25.74%-30.03%, the ultimate displacement increase by 22.75%-106.39%, and the residual displacement decrease by 43.70%-61.42%, which indicates better anti-seismic performance. The AC-200 specimen has the largest depth of notch, and its residual displacement is larger than that of the other assembled bridge piers, with poorer energy dissipation capacity. The peak load and yield load of assembled bridge piers increase with the axial compression ratio and the height of cast-in-place ECC segments and decrease with the increase in the length-to-slender ratio. The ductility factor increases with the height of the cast-in-place ECC segment and decreases with the increase in the length-to-slender ratio and axial compression ratio. It is recommended that the depth of the notch in hybrid connections should not exceed 75% of the side length of the tenon.More>

2023, 23(5): 104-117. doi: 10.19818/j.cnki.1671-1637.2023.05.006

FullText HTML (102) PDF (14692KB) (112)

Mechanism of rail vibration absorber suppressing rail corrugation in Cologne-egg fastener section

CUI Xiao-lu, XU Jia, LI Tong, XU Xiao-tian, QI Wei, LIU Jin-zhi

Abstract: The field investigation of rail corrugation in Chongqing Metro Line 1 was implemented. The dynamical model of the vehicle-track system in the sharp curved section with Cologne-egg fastener was established, and the dynamical characteristics of the leading wheelset passing the section were studied. Based on the theory of friction self-excited vibration of the wheel-rail system, the finite element model of the wheelset-rail-vibration absorber system of the corresponding section was established. The complex eigenvalue and the instantaneous dynamic methods were applied to study the generation mechanism of rail corrugation and the suppression mechanism of the rail vibration absorber. The influence laws of connection parameters and installation methods of the rail vibration absorber on rail corrugation were explored by the control variable method. Analysis results show that the creep force between the leading wheelset and the rail tends to be saturated in the sharp curved section with Cologne-egg fastener, which can easily cause the friction self-excited vibration of the wheel-rail system with a frequency of 477.65 Hz, thereby leading to the rail corrugation with the wavelength of 30-40 mm on the surface of the low rail. By installing the rail vibration absorber, the friction self-excited vibration of the wheel-rail system at the corresponding frequency can be effectively reduced, which further suppresses the formation of rail corrugation in the sharp curved section with Cologne-egg fastener. Increasing the connection stiffness and damping of the rail vibration absorber within a certain range or changing the installation method of the rail vibration absorber can be beneficial to reduce the friction self-excited vibration of the wheel-rail system, thus inhibiting the generation and growth of rail corrugation. When the lateral connection stiffness and damping of rail vibration absorber are 60 MN·m^-1and 50 kN·s·m^-1, the longitudinal connection stiffness and damping of rail vibration absorber are 60 MN·m^-1 and 50 kN·s·m^-1, and the vertical connection stiffness and damping of rail vibration absorber are 120 MN·m^-1 and 100 kN·s·m^-1, respectively, and the rail vibration absorber is installed continuously on both sides of the rail web, the occurrence possibility of friction self-excited vibration of the wheel-rail system is the smallest.More>

2023, 23(5): 118-128. doi: 10.19818/j.cnki.1671-1637.2023.05.007

FullText HTML (225) PDF (14206KB) (101)

Lateral deviation model test of temporary anchorage system for immersed tube in Shenzhen-Zhongshan Link

YAN Lei, HAN Heng, HE Shuan-hai, XU Guo-ping, DENG Bin, YAN Jin-ning, XIN Shi-hao

Abstract: To find out the lateral deviation limit of the anchorage system during the jointing construction of the immersed tube in Shenzhen-Zhongshan Link, the displacement ability of the anchorage system was studied by the combination of numerical simulation and model test. The finite element model of the anchorage system was established, and the loading grading standard of the full-scale model test was determined based on the finite element analysis results. In view of the actual stress state of the anchorage system, the axial load grade of the tie rod was determined. The test simulated the initial installation deviations of 5 cm in horizontal and vertical directions, and the structure was loaded in four working conditions. In addition, the stress and displacement were tested. Research results show that under the given axial load of the tie rod, the safety reserve of the anchorage system decreases gradually with the increase in the lateral deviation. Under the axial test load of 1 000 kN of a single tie rod and the lateral deviation of 5 cm, the structure is in an elastic working state, and the maximum Mises stresses of the anchor plate and rib plate reach 190.8 and 179.3 MPa, respectively. The safety reserves relative to their design strengths of 295 and 280 MPa are 35.3% and 36.0%, respectively. Under 1.2 and 1.5 times of the axial test load, when the lateral deviation is applied to 5 cm, the anchorage system is still in an elastic working state. The maximum Mises stresses of the anchor plate and rib plate increase from 221.1 and 196.8 MPa to 286.8 and 260.5 MPa, respectively. The average designed safety reserve decreases from 27.4% to 5.0%. The maximum stress of the tie rod increases from 473.8 MPa to 623.7 MPa, and the yield safety reserve decreases from 43.3% to 25.3%. In the limit lateral deviation test, under 1.5 times of the axial test load, the anchor plate reaches the designed strength when the lateral deviation is 6 cm. When it continues to increase to 12.8 cm, the anchor plate yields first, and it is considered that the anchorage system has failed. At this time, the stress of the tie rod is 704.8 MPa, and the yield safety reserve is 15.6%. Therefore, it is recommended that the lateral deviation control value of immersed tubes should be 6 cm during the underwater jointing construction.More>

2023, 23(5): 129-142. doi: 10.19818/j.cnki.1671-1637.2023.05.008

FullText HTML (151) PDF (26100KB) (73)

Prediction of engine performance degradation based on adaptive change points

LI Yao-hua, ZHANG Cheng

Abstract: To effectively utilize the monitoring big data to accurately identify the performance status and predict the performance degradation process of civil aircraft engines, a reliability evaluation model considering the uncertain degradation characteristics of civil aircraft engine performance parameters in different stages was proposed, so as to address the lack of fault data and the multi-stage degradation characteristics of civil aircraft engines during the performance degradation process. The change point detection model based on the Bayesian information criterion (BIC) was improved by the dynamic adaptive window width, and the adaptive change point was identified by the improved BIC with adaptive window width. Based on the identified adaptive change points, a distribution function model of the uncertain Liu process was established in stages. The reliability evaluation was conducted according to the mathematical properties of the first threshold of the performance degradation process of civil aircraft engines. In addition, the accuracy and superiority of the model were verified by comparing the sample data of performance degradation of civil aircraft engines. Analysis results indicate that the mean square error of degradation process in stages described by the change points is 5.8×10^-28 after identifying the change points of performance degradation process of civil aircraft engines by using the BIC change point detection model with the improved adaptive window width. Under the conditions that the adaptive window width has different changing rules, the identified change points have no obvious change. Therefore, the model can accurately identify the adaptive change points of performance degradation process of civil aircraft engines and has strong robustness. When the uncertain Liu process in stages is used to analyze the dynamic degradation law of performance parameters of civil aircraft engines, the average evaluation error reduces by about 23.69% compared with the original Liu process model, and the reliability evaluation results are more accurate. Due to the Lipschitz continuity, the improved model can accurately predict the reliability level of performance degradation process of civil aircraft engines in a certain period of time in the future. It can be seen that the established improved reliability evaluation model can provide theoretical methods for the performance status monitoring and health management application of civil aircraft engines in practical engineering.More>

2023, 23(5): 143-151. doi: 10.19818/j.cnki.1671-1637.2023.05.009

FullText HTML (129) PDF (3355KB) (54)

Mass and hot spot temperature rise balance optimization of dry-type on-board traction transformers for EMUs

GUO Lei, CAI Feng-lin, YUAN Shuai, ZHU Qiu-yue, WANG Dong-yang, ZHOU Li-jun

Abstract: To address the mutual constraint between the mass and hot spot temperature rise of dry-type on-board traction transformers during the optimization process, an optimization method combining the simplified computational fluid dynamics (CFD) model simulation with the multi-objective algorithm was proposed. To enhance the computational efficiency of the CFD temperature rise simulation, a simplified modeling method for the CFD of dry-type on-board traction transformer winding was proposed based on the thermal-electric transfer analogical equivalence principle. A temperature rise test platform for simulating the operating conditions was established to validate the effectiveness of the simplified modeling method. Based on the simulation results of temperature rise and response surface method using the simplified model under the coupling of multiple fields, a mathematical explicit model reflecting the intrinsic relationship between the hot spot temperature rise and mass structural parameters of the dry-type on-board traction transformer was constructed. Furthermore, in view of the constraints of electricity, magnetism, and dimensions of the on-board traction transformer, an equilibrium optimization method based on the non-dominated sorting multi-objective genetic algorithm was proposed, and the optimized scheme was compared with the initial scheme. Research results demonstrate that the equivalent simplified modeling method is rapid and concise, and it has a high computational accuracy. In the simulation model with 170 turns of winding, the simulation time reduces from 4.00 h to 0.67 h. The average relative difference between the simplified model and the specific model in the temperature rise simulation results is 0.609%, and the maximum relative difference is 2.169%. The simplified modeling method eliminates the tiny spacing of the CFD model by using the equivalent principle and significantly reduces the number of solid region grids while ensuring the grid quality. The improvement of the computational efficiency is positively correlated with the number of winding turns to be simplified. Compared with the initial scheme, the optimized scheme reduces the hot spot temperature rise of the dry-type on-board traction transformer by 33.57% and decreases the mass by 29.20 %.More>

2023, 23(5): 152-162. doi: 10.19818/j.cnki.1671-1637.2023.05.010

FullText HTML (46) PDF (8205KB) (45)

Adaptive guidance control of super-twisting sliding mode for virtual track train

ZHANG Zhong-hua, YANG Cai-jin, ZHANG Wei-hua

Abstract: In order to improve the robust performance of autonomous guidance control of virtual track trains subject to parameter uncertainties and unknown external disturbances, the multi-input and multi-output overdrive control problem during train operation was studied, a nonlinear guidance control model of multi-articulated virtual track train was established based on Lagrange's formula, and the equivalent lateral tire force was used as the control input. By employing discrete point coordinates of the virtual track and the speed of the train, a reference model was built to calculate the location, speed, and acceleration of the train, and an independent guidance controller and longitudinal speed controller of the train were designed. By applying Lyapunov method, based on the traditional sliding mode control (SMC) and adaptive super-twisting sliding mode (ASTSM), two guidance controllers of the train were designed, respectively, and the control command of a steer-by-wire system was calculated by an inverse tire model. Moreover, a wheel speed allocation model was established, in which the longitudinal train speed control was converted to the speed and electromagnetic torque control of each in-wheel motor on the basis of the reference velocity vector. A dynamics simulation model composed of seven carriages was constructed, and the responses of in-wheel motor speed and electromagnetic torque were analyzed by variable speed and compound path test. The distribution law of the articulated force between vehicle modules was revealed, and the robustnesses of SMC and ASTSM under uncertain parameters and unknown external disturbances were compared. Research results show that the proposed guidance control model, motion reference model, and wheel speed allocation model are effective. The tracking errors of longitudinal velocities of vehicle modules are less than 1.5 km·h^-1, and the tracking error rates of wheel speeds are not more than 1%. Compared with the SMC, the proposed ASTSM has better adaptive robustness in the presence of unmodeled dynamics, 50% load changes, and unknown disturbances, and the deviation of each axle center can gradually converge to around 0 in finite time. Under the lateral force interference, the root mean square deviation and maximum deviation of the ASTSM for all axis centers are 10 and 42 mm, and decrease by 82% and 61%, respectively. In addition, the steady-state deviation of the ASTSM on the curved section is not significant, and the articulated angles can consistently converge to a stable value, which guarantees the stability of the virtual track train.More>

2023, 23(5): 163-182. doi: 10.19818/j.cnki.1671-1637.2023.05.011

FullText HTML (257) PDF (24879KB) (51)

Optimal configuration and allocation of berth resources in multi-port regions

ZHENG Jian-feng, ZHAO Yu-xing, LIU Xin-tong, GUO Ni-nan

Abstract: Under the background of integrated regional port development, by adjusting berthing ports for the ships from different liner shipping companies, the configuration and allocation of berth resources in multi-port regions were investigated. To improve berth utilization, different liner shipping companies were combined to form stable liner ship clusters and determine the optimal matching between berth resources and different liner ship clusters in multi-port regions. A set partitioning model was established to minimize the number of berths and berthing ports to be adjusted, and a three-stage optimization approach dependent on the queuing theory and cooperative game theory was presented. Three ports (Hong Kong Port, Yantian Port, and Shekou Port) in the Pearl River Delta region, with the ships from four liner shipping companies berthing at the region, were numerically analyzed. Numerical analysis results show that by using the three-stage optimization approach, the average queuing length of the ships from these four liner shipping companies decreases from 23.569 1 to 22.930 2, therefore the integration of berth resources in multi-port regions is helpful in relieving port congestion and ship queuing. The number of berths to be allocated by three ports serving four liner shipping companies reduces from 31 to 27, indicating that the reasonable configuration and allocation of berth resources in multi-port regions can not only improve berth utilization, but also reduce the repetitive construction of port resources of different ports. From the perspective of the number of ships served by berths, the port has different attractiveness when serving the ships of various liner ship clusters, indicating that the port should properly select liner shipping companies for serving their ships in order to improve the operation effectiveness of berth resources.More>

2023, 23(5): 183-191. doi: 10.19818/j.cnki.1671-1637.2023.05.012

FullText HTML (261) PDF (5695KB) (98)

A multi-objective route optimization method for passenger evacuations at subway stations during a fire outbreak

YANG Xiao-xia, ZHANG Rui, LI Yong-xing, QU Da-yi

Abstract: A passenger evacuation network at subway stations was established, the degrees of network nodes were analyzed to identify key nodes, and a modified walking evacuation network was proposed after node failures. A time prediction model for passengers traveling through the gate and stair/escalator nodes was designed based on the support vector regression algorithm, and its prediction performance was analyzed. A quantitative relationship between the number of passengers and travel time was obtained. Three objective functions, namely the total evacuation time including the node and road section travel time, the total road risk, and the total congestion cost, were established. A multi-objective route optimization model for passenger evacuation at subway stations during a fire outbreak was constructed, and a solution method of optimization model was proposed based on the genetic algorithm. The evacuation movement of passengers at subway stations during a fire outbreak was simulated, and the evacuation efficiencies under the Pareto solution of the route optimization model was analyzed, then the optimization degree of the route optimization strategy was evaluated. A WeChat applet for passenger dynamic guidance was designed, providing a possible solution for the timely release of evacuation route recommendation information. Research results indicate that the mean absolute error of the passenger travel time prediction model at the nodes for the validation set can be as low as 0.000 375, and the robust indicator value is up to 0.999 334, indicating a high degree of consistency between predicted data and real data. The average relative error between the field collected data at the gate and the simulated data is 4.9%. The significance values of normality test, homogeneity test of variance, and independent sample test are all greater than 0.05, verifying that the PathFinder software can simulate passenger movements accurately. Compared with the normal evacuation without optimization strategies, the optimization degrees of the route optimization model under three sets of Pareto solutions are 16.7%, 15.9%, and 18.0%, respectively. Therefore, corresponding evacuation optimization strategies can be selected based on specific evacuation scenarios, risk factors, service quality requirements, and other indicators.More>

2023, 23(5): 192-209. doi: 10.19818/j.cnki.1671-1637.2023.05.013

FullText HTML (152) PDF (22629KB) (100)

Fast intelligent decision of operation schemes for construction of intelligent crude oil pipelines

WANG Jun-fang, CAO Dan-fu, JIAO Jie, YU Hong-mei, YUAN Qing, YU Bo, CHEN Zhi-min, DENG Ya-jun

Abstract: To solve the real-time optimization problem during the construction of intelligent crude oil pipelines, an intelligent decision model of operation schemes with the optimization goals of minimizing the energy consumption and unsafe factor was established from the perspectives of energy saving and operational safety. Based on the differential evolution algorithm, the ideas of improving the reliability and optimization efficiency of the optimization algorithm were proposed from the perspectives of algorithms, including from the processing of mutation decision variables beyond bounds and the mutation operator of discrete decision variables. Combined with the algorithm computation process and parallel computing framework, four parallel computing strategies were proposed. The Yizheng-Changling Crude Oil Pipeline (Yichang Pipeline) with a length of about 900 km was used as the tested pipeline to verify and further analyze the algorithm improvement ideas and parallel computing strategies. Research results indicate that the intelligent decision method of operation schemes combining the intelligent decision model and the optimization algorithm can reduce the energy consumption cost of the Yichang Pipeline by 7.22% on the premise of safe operation of the pipeline, and the energy-saving effect is obvious. The improved processing method of mutation decision variables beyond bounds and the mutation operator of discrete decision variables based on the floating-point rounding can improve the reliability of the optimization results of crude oil pipeline operation schemes, and the former can reduce the optimization computation time by at least half, and the latter can reduce the optimization computation time by at least two-thirds. There are some differences in the advantages and disadvantages of different parallel computing strategies for different computer configurations. Under the optimal parallel computing strategy, the optimization computation time on the server reduces from 220 s to 10 s, and the acceleration ratio can reach 22 times. It can be seen that the acceleration ratio of optimization computation can be accelerated by over 130 times by using the fast intelligent decision method of operation schemes combining the algorithm improvement ideas and parallel computing strategies, and the optimization computation time significantly reduces. The above results demonstrate the effectiveness of the intelligent decision method for the fast operation optimization of the crude oil pipeline.More>

2023, 23(5): 210-222. doi: 10.19818/j.cnki.1671-1637.2023.05.014

FullText HTML (65) PDF (11065KB) (74)

Application of combined empowerment cloud model to expressway channel adaptability assessments

LI Bin, ZHU Peng-peng, XIAO Run-mou, LI Zi-tian, JIN Yin-li

Abstract: In order to scientifically assessment the adaptability between expressway channels and regional development, the influencing factors of expressway channels on the regional economy were analyzed. The evaluation index screening method of the anti-image correlation matrix was used for index dimensionality reduction, and the evaluation index system of expressway adaptability of regional channels was established. The weights of each evaluation index of the model were calculated by the objective assignment through the gray correlation, and the errors caused by the subjective judgment of the analytic hierarchy process (AHP) were compensated in the algorithm. A cloud model with a hybrid AHP-gray correlation degree constrained cone was developed, and 46 road sections of the Shenhai Expressway channel in 2019 were evaluated. Relevant improvement opinions and specific measures were proposed to address the problems of the non-adaptive road sections in terms of capacity expansion and reconstruction, differentiated charging, and active traffic management. Research results show that the model complexity can reduces substantially without affecting the model accuracy by reducing the expressway adaptability evaluation indexes from 18 to 9. By evaluating the Shenhai Expressway, the moderately over-adapted road sections, the overall adaptive road sections, the preliminary adaptive road sections, the relative lagging road sections and the seriously constrained road sections account for 6.52%, 21.74%, 43.48%, 21.74% and 6.52%, respectively. Compared with the traditional data enveloping analysis (DEA) model, the cloud model with AHP-grey correlation degree constraint cone has 17.39% fewer moderately over-adapted road sections, 43.48% more preliminary adaptive road sections, and 6.52% more seriously constrained road sections. In particular, the degree of maladaptation is the most serious in the inner sections of Fuzhou City, Quanzhou City, Jinjiang City, and Xiamen City, which are not evaluated by the traditional DEA model. It can be seen that the accuracy and scientificity of the evaluation results can be improved by the cloud model using the AHP-gray correlation degree combination assignment, and it is an effective method to solve the problem of expressway channel adaptability assessment.More>

2023, 23(5): 223-233. doi: 10.19818/j.cnki.1671-1637.2023.05.015

FullText HTML (92) PDF (9031KB) (96)

Standee preference for standing areas in urban buses

YAN Sheng-yu, BAI Zhao-ran, WEN Fu-hua, ZHOU Ji-biao, CHEN Li-mei

Abstract: To reveal the standee preference for standing areas in urban buses, a multinomial logit (MNL) model of standee preferences was proposed based on the stochastic utility theory. According to standee preference flow and seat arrangement, three key independent factors that affected the preference were introduced, including the looseness of standing, the convenience of getting-off, and the probability of obtaining a seat. The algorithms and thresholds of three factors were proposed, and the distribution law and coupling relationship of each factor among all the standing areas were put forward. The parameters to be estimated in the MNL model were calibrated by Newton iteration method in MATLAB. The typical urban bus of 12 m was taken as a case, and the selection model of each standing area was given based on the investigation data of 22 bus lines in Xi'an. In addition, the standee preference for standing areas under different average standee densities in buses was analyzed. Analysis results show that the calibrated MNL model can effectively reflect standee preferences. The priority of standee for the three independent factors is the convenience of getting-off, the looseness of standing, and the probability of obtaining a seat. There is a coupling relationship of looseness of standing between the two standing areas in the wheelbase. The standee preference for the looseness of standing and the probability of obtaining a seat in the reference area is weaker than that in the non-reference area. When the average number of standing passengers per square meter in the bus is no more than 2, the preference decrease rate of area 3 is 35.95%, while the preference increase rate of area 2 is 19.99%, with a significant phenomenon of coupling. When the average number of standing passengers per square meter in the bus is more than 2, area 2 will significantly relieve the passenger flow in area 1, and the standee always prefers area 1 than area 4. Standee preference for standing areas presents a convergence feature. The study on the standee preference for standing areas is of great value to measure the effect of seat arrangement and passenger flow adaptation, guide the emergency evacuation and diversion of passenger flows, and improve the service quality of urban bus travel.More>

2023, 23(5): 234-241. doi: 10.19818/j.cnki.1671-1637.2023.05.016

FullText HTML (423) PDF (1946KB) (87)

Lane-changing decision model of connected and automated vehicles driving off ramp

HAO Wei, ZHANG Zhao-lei, WU Qi-yu, YI Ke-fu

Abstract: A safety risk-based lane-changing decision model of connected and automated vehicles (CAVs) driving off the ramp in mixed traffic flow was proposed to macroscopically characterize the behaviors of CAVs driving off the ramp in the CAV lane. The model abstracted the lane-changing gap selection process into Bernoulli experiments of successful or unsuccessful lane-changing, and a lane-changing success rate formula was set up based on the traffic flow theory. A driving off ramp lane-changing decision cost function considering lane-changing safety and efficiency was proposed, in which the weight parameters of safety and efficiency were determined based on different driving modes, so as to determined the optimal lane-changing intention generation point for CAVs and provided instructions for CAV lane-changing. Numerical analysis results show that the success rate of CAV driving off the ramp is determined by the preparation distance of lane-changing, traffic demand, and CAV penetration rate. The cost function has an obvious inflection point with the change of CAV penetration rate. When the traffic volume is 2 400 veh·h^-1, the optimal lane-changing intention generation point for CAVs is 1 km away from the entrance of the off-ramp. When the traffic volume increases to 4 000 veh·h^-1, the optimal lane-changing intention generation point is 2.5 km away from the entrance of the off-ramp. When the traffic volume is greater than 6 400 veh·h^-1, the CAV needs to increase aggressiveness to drive off the highway efficiently. The cost function first decreases and then increases as the CAV penetration rate increases. If the penetration rate is lower than the inflection point penetration rate, the cost function can be reduced by increasing the preparation distance of lane-changing. If the penetration rate is higher than the inflection point penetration rate, reducing the preparation distance of lane-changing is necessary to reduce the cost function. Simulated results show that the traffic safety of driving off the ramp significantly influenced by the traffic demand and CAV penetration rate. The time-to-collision reduces to 76.23%, with the penetration rate increasing from 30% to 60%. 2 tabs, 8 figs, 31 refs.More>

2023, 23(5): 242-252. doi: 10.19818/j.cnki.1671-1637.2023.05.017

FullText HTML (251) PDF (5169KB) (143)

Federated heterogeneous model and algorithm for personal travel recommendation

YOU Lin-lin, HE Jun-shu, CHEN Kun-xu, HE Jia-qi, YUAN Shao-xin, ZHAO Juan-juan, CAI Ming

Abstract: To achieve personal travel recommendations by considering both the preference heterogeneity and data privacy, based on the model parametric aggregation and distributed training supported by the federated learning (FL) computing paradigm, a federated mixed Logit (FMXL) model was proposed by decoupling the standard mixed Logit model to separate the parameter estimation of local individual preferences and global population differences. In order to eliminate the dependence of the model on the original data, two federated Gibbs sampling algorithms, to be standardized or aggregated, were designed, to achieve the hierarchical estimation of the model through the interaction of local and global parameters. The proposed model and algorithm were validated for offline and online travel recommendation scenarios based on Swiss Metro data. Analysis results show that for offline scenario, the FMXL model based on two federated Gibbs sampling algorithms increase the log-likelihood value by 157.8 and 153.2, and the prediction rate by 12.3% and 12.1%, respectively, compared with the standard multinomial Logit model. In addition, the computation time reduce by 64.2% and 76.9%, respectively, and the communication times both reduce by 86.2% compared with the mixed Logit model based on the centralized Gibbs sampling algorithm. For the online scenario, both the log-likelihood value and the prediction rate of the FMXL model show an increasing trend, and the computation and communication times of the whole estimation process are lower than those of the standard mixed Logit model. Overall, with the data privacy as the precondition, the federated training of the MXL model ensures the accuracy of travel recommendations and effectively enhances the timeliness of travel recommendations by fully utilizing the idle computing power on the user side, reflecting the high adaptability and scalability of the proposed model and algorithms. In addition, the intelligent progress of the transportation system can be promoted effectively by personal travel recommendations based on the FMXL model. 3 tabs, 4 figs, 30 refs.More>

2023, 23(5): 253-263. doi: 10.19818/j.cnki.1671-1637.2023.05.018

FullText HTML (156) PDF (2766KB) (71)

Reciprocal velocity obstacle algorithm for collision risk avoidance of intelligent connected vehicles

WANG Shun-chao, LI Zhi-bin, CAO Qi, WANG Bing-tong, DING Hong-liang

Abstract: A reciprocal velocity obstacle (RVO) algorithm for collision risk detection and collaborative path planning for collision avoidance of intelligent connected vehicles was constructed to address the dynamic collision avoidance in the collaborative driving among multiple intelligent vehicles. Based on the artificial potential field (APF) theory, a vehicle collision risk potential field (CRPF) was built to quantify both the collision risk intensity and risk area. According to the interactive effect of vehicle driving behavior, an RVO algorithm was constructed to determine the conditions and rules for collaborative collision risk avoidance among conflicting vehicles. Based on the vehicle dynamics constraints, a dynamic window approach was established to identify the feasible velocity solution set for collision risk avoidance. Based on the principle of model predictive control, the optimization theory was employed to build a path planning model for the vehicle collision risk avoidance. The effectiveness of the proposed collision risk avoidance algorithm was tested and compared with other collision avoidance algorithms by constructing the collision avoidance simulation scenarios for the single conflicting vehicle, multiple conflicting vehicles, and conflicting traffic flow in bottleneck areas under an intelligent connected environment. Research results show that compared to other comparative algorithms, the security performance and efficiency performance of the RVO algorithm improves by more than 8.6% and 9.6%, respectively, indicating that the proposed RVO algorithm can effectively reduce the collision avoidance velocity and trajectory fluctuations for conflicting vehicles via the collaborative collision avoidance behavior, effectively avoid the collision conflicts among vehicles with nonlinear speeds and trajectories and mitigates the multiple vehicle collisions and significant traffic flow fluctuations in bottleneck areas. The proposed collision avoidance algorithm outperforms other algorithms in bottleneck areas with large-scale vehicle conflicts, enhancing the vehicle traffic efficiency by 10.42% and reducing the vehicle collision risk by 47.32%. Thus, the algorithm has sound performance in coordinating the collision avoidance behavior of large-scale conflict vehicles and reducing the vehicle collision risks and operation delays. 2 tabs, 20 figs, 41 refs.More>

2023, 23(5): 264-282. doi: 10.19818/j.cnki.1671-1637.2023.05.019

FullText HTML (375) PDF (21717KB) (154)

User Center

Journal Info

Collection of Source JournalsMore>

2023 Vol. 23, No. 5

Search Type

Search Journal

LinksMore>