Table of Content

25 April 2024, Volume 52 Issue 4

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2024, 52(4):  0. 

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Biological Engineering

Effects of Trigger Transposable Element-Derived 1 on the Growth of Hepatocellular Carcinoma



GAO Ping, YE Zijian, QIAN Xiaoyu, et al

2024, 52(4):  1-7.  doi:10.12141/j.issn.1000-565X.230248

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Cell cycle dysregulation is one of the most important hallmarks of cancer. Bioinformatics studies have suggested that trigger transposable element-derived 1 (TIGD1) is expressed at higher levels in the tumor tissues from the clinical hepatocellular carcinoma (HCC) samples and may be related to the cell cycle. However, the underlying mechanism is unclear. To explore the specific mechanism of TIGD1 regulating the growth of hepatocellular carcinoma cells, this paper first analyzed the growth of HCC cell line Hep3B with TIGD1 knockdown by using shRNA plasmid. The results show that cell growth is inhibited. Then, cell cycle analysis by flow cytometry was used to investigate the effect of TIGD1 knockdown on cell cycle of HCC. The results show that the cell cycle progression of the Hep3B cell line is mainly blocked in the G2/M phase. Next, Immunoprecipitation (IP) experiments were used to verify the protein molecules with which TIGD1 might interact. And the results show that TIGD1 may be bound to Aurora kinase interacting protein 1 (AURKAIP1). Further, the Co-IP experiment confirmed the interaction between TIGD1 and AURKAIP1. AURKAIP1 is known to regulate the proteasomal degradation pathway of Aurora kinase A (AURKA), and AURKA is a mitotic regulatory protein that is closely associated with cell cycle progression. The paper further explored the effect of TIGD1 on AURKA protein levels, and the results show that TIGD1 knockdown obviously decreases the protein level of AURKA without affecting its mRNA level in Hep3B cells. In conclusion, TIGD 1 may affect cell cycle progression by regulating the post-transcriptional levels of AURKA in HCC cells, thus affecting the development of HCC.

Molecular Modification of Taq DNA Polymerase and Its Application in Probe-Based qPCR Direct Amplification System



HU Songqing, YUAN Jiahui, LIU Guangyi, et al

2024, 52(4):  8-16.  doi:10.12141/j.issn.1000-565X.230090

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As the key component of quantitative real-time polymerase chain reaction （qPCR） technology, Taq DNA polymerase’s performance directly affects the further development of qPCR technology. However, the wild-type Taq DNA polymerase has inadequate properties in inhibitor tolerance and elongation performance. To obtain Taq DNA polymerase with high performance, this study fused the double-stranded DNA-binding protein Sso7d or Sto7d to the N-terminal or C-terminal of wild-type Taq DNA polymerase by genetic engineering technology, which four soluble expression transformants were constructed, and then the better transformant was screened by tolerance test. The results show that the better transformant Taq-Sto has the highest tolerance, with no impact on its thermal stability, and the target can be successfully amplified by Taq-Sto under the extension condition of 1 s/kbp, indicating that Taq-Sto has enhanced extension performance. It also shows good tolerance to humic acid, tannic acid and whole blood in TaqMan qPCR system. EMSA experiment shows that the binding affinity of Taq-Sto to DNA template is improved, which is beneficial to enhancing the competitiveness of Taq-Sto to DNA template. Taq-Sto was applied to the TaqMan qPCR detection of African swine fever virus (ASFV). Compared with commercial reagents, Taq-Sto has lower detection limit of ASFV, and the detection sensitivity in 2%~6% (volume fraction) pig fecal samples or pork samples is 100.0% and 85.4%, respectively, indicating that Taq-Sto has more advantages in the field of direct qPCR detection. The results provide a reference for the development of DNA polymerase with better performance, which is conducive to further promoting the practical application of qPCR technology.

Improvement Effects of Co-administration of Cartilage Extract, Turmeric Extract, Pueraria Lobata and Coix Seed Extract on Cartilage Damage of Rats with Knee Osteoarthritis



DING Liugang, GUAN Ting, MIAO Jindian, et al

2024, 52(4):  17-25.  doi:10.12141/j.issn.1000-565X.220815

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This paper studied the synergistic effects of turmeric extract, cartilage extract, Pueraria lobata and Coix (Coix lacryma-jobi) seed extract alone and the combination on the improvement of cartilage damage of rats with knee osteoarthritis. The synergistic effects of the three extracts in rat knee osteoarthritis were evaluated mainly by reducing knee swelling (inflammation), protecting chondrocyte and repairing joint cartilage. The results show that the turmeric extract has a more obvious effect in inhibiting joint swelling and improving cartilage damage, which is specifically manifested in the ability to better improve the levels of Collagen Ⅱ, matrix metalloproteinase 3 (MMP3), cartilage oligomeric matrix protein (COMP), tumor necrosis factor-alpha (TNF-α) and superoxide dismutase (SOD). The cartilage extract significantly improves the arthritic lesions by improving the levels of MMP3, COMP, TNF-α, prostaglandin E2 (PGE2) and SOD. Pueraria lobata and Coix seed extract improves the levels of Collagen Ⅱ and SOD, inhibits the elevation of MMP3, COMP, TNF-α and interleukin 1β (IL-1β), and improves cartilage damage of rats with knee osteoarthritis. The combined use of the three extracts exhibits better effects on the repair of rat knee cartilage. These data imply that by optimizing the ratio of turmeric extract, cartilage extract and Pueraria lobata and Coix seed extract, functional foods can be developed with significant anti-inflammatory and cartilage repairing effects and contribute to the realization of “Healthy China 2030”.

Food Science & Technology

Effect of Tea Polyphenols on Soy Protein Isolate-Stabilized Emulsions and Interfacial Protein Displacement by Bile Salts



GE Ge, LIN Li, ZHENG Jiabao, et al

2024, 52(4):  26-32.  doi:10.12141/j.issn.1000-565X.230325

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The soy protein isolate was modified by adding different concentrations of tea polyphenols extract to prepare the oil-in-water (O/W) emulsion. The interfacial tension, interfacial protein adsorption fraction, emulsion particle size and zeta potential were investigated to explore the effect of tea polyphenols on the properties of soy protein isolate emulsion and interfacial protein displacement. The results show that the interfacial tension of soy protein isolate is increased after the addition of tea polyphenols. When soy protein isolate (1%, mass concentration) and soy oil are prepared into O/W emulsion with 9∶1 mass ratio by high-speed shear and ultrasound, tea polyphenols addition can improve the emulsion stability. Compared to the blank control group, when the amount of tea polyphenols added is 0.04%, the particle size of emulsion decreases significantly from 1.702 μm to 1.203 μm (P < 0.05), the protein adsorption fraction increases significantly from 9.22% to 20.68% (P < 0.05), and the zeta potential increases significantly from 25.7 mV to 27.1 mV (P < 0.05), respectively. Soy protein isolate shows resistance to bile salts displacement at the oil-water interface. In addition, the soy protein isolate modified by tea polyphenols is more difficult to be displaced by bile salts because of the strong electrostatic interaction and the thicker interface layer. Lipid digestion in intestine is an interfacial process. Exploring the interfacial displacement between protein and bile salts is beneficial to the study of lipid metabolism and food precise design.

Inhibitory Effects and Molecular Mechanism of Wheat Antioxidant Peptides on Oxidative Stress Injury in Human Embryonic Kidney Cells



LIU Wenying, REN Jie, WU Hanshuo, et al

2024, 52(4):  33-41.  doi:10.12141/j.issn.1000-565X.230082

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The study firstly established oxidative stress injury model of human embryonic kidney cells (HEK293) by the induction of 2,2-azobis (2-methylpropionamidine) dihydrochloride (AAPH) to evaluate the antioxidant activity of five wheat protein-derived peptides Leu-Tyr (LY), Pro-Tyr (PY), Tyr-Gln (YQ), Ala-Pro-Ser-Tyr (APSY) and Arg-Gly-Gly-Tyr (RGGY). Then, it used quantum chemistry and molecular docking techniques to predict the optimal configuration and binding effect of five wheat protein-derived peptides combined with 2,2-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS), and to explore the molecular mechanism of wheat protein-derived peptides. The results of cell test show that after the action of five wheat protein-derived peptides, the cell death rate significantly decreases to below 3.68% (P < 0.05), and the generation of reactive oxygen species (ROS) induced by AAPH was significantly reduced (P < 0.05), making the ROS content tend to normal levels. All five wheat protein-derived peptides show good total antioxidant capacity and free radical scavenging capacity of 1,1-Diphenyl-2-picrylhydrazyl (DPPH) (P < 0.05). RGGY shows the strongest total antioxidant capacity, with an activity value of (1.46 ± 0.08) mmol/L Trolox, followed by APSY, YQ, PY and LY. The DPPH free radical scavenging ability of YQ is the strongest, with a scavenging rate of 61.34% ± 2.24%, followed by APSY, RGGY, PY and LY. The results of molecular docking show that the CDOCKER interaction energy (-CIE) scores of the five wheat protein-derived peptides are 13.304 9, 13.397 3, 13.412 1, 16.768 5 and 16.268 3, respectively, which can effectively interact with ABTS, mainly through the formation of strong hydrogen bonds and hydrophobic forces between ABTS molecules to exert antioxidant activity.

Mechanical Engineering

Multi-Object Recognition and 6-DoF Pose Estimation Based on Synthetic Datasets



HU Guanghua, OU Meitong, LI Zhendong

2024, 52(4):  42-50.  doi:10.12141/j.issn.1000-565X.230327

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Multi-object recognition and 6-DoF (degree of freedom) pose estimation are the key to achieve automatic sorting of robots in the state of unordered stacking of materials. In recent years, methods based on deep neural networks have received much attention in the multi-object recognition and 6-DoF pose estimation fields. Such methods rely on a large number of training samples, however, the collection and labeling of samples is time-consuming and laborious, which limits its application. In addition, when the imaging conditions are poor and the targets are occluded by each other, the existing pose estimation methods cannot guarantee the reliability of the results, resulting in grasping failures. To this end, this paper presented a method for target recognition, segmentation and pose estimation based on synthetic data samples. Firstly, multi-view RGB-D synthetic images of virtual scenes were generated using 3D graphics programming tools based on the 3D geometric models of the target objects, and then style transfer and noise enhancement was performed, respectively, on the generated RGB images and the depth images to improve their realism, so that they are suited for the detection in real scenes. Next, the YOLOv7-mask instance segmentation model was trained with synthetic datasets and tested by real data. The results demonstrate the effectiveness of the proposed method. Secondly, the ES6D model was utilized to estimate target poses based on the segmentation results, and an online posture evaluation method was proposed to automatically filter out severely distorted estimation results. Finally, a pose estimation correction strategy based on active vision technique was proposed to guide the robot arm to move to a new viewpoint for re-detection, which can effectively solve the problem of pose estimation deviation caused by occlusion. The above methods have been verified on a self-built 6-DoF industrial robot vision sorting system. The experimental results show that the proposed algorithm can well meet the requirements of recognition and 6-DoF posture estimation of common workpieces in complex environments.

Trajectory Friction Compensation Algorithm for Robots Based on Velocity Control



YE Bosheng, LI Siao, TAN Shuai, et al

2024, 52(4):  51-58.  doi:10.12141/j.issn.1000-565X.230368

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Currently, robots are extensively utilized in industrial manufacturing. However, due to the influence of joint friction and other factors in the robot system, the robot trajectory tracking accuracy is difficult to meet the requirements of high-precision production. In this study, a friction compensation control algorithm in speed mode was proposed to mitigate the impact of non-linear friction factors in the mechanical structure and unmodelled disturbances on the robot’s operational stability and machining precision. The optimal excitation trajectory was designed by a combination of Fourier series and fifth-order polynomial. Dynamic parameters were then pre-identified by the least squares method and iteratively optimized through the Levenberg-Marquardt method to establish a more precise robot dynamic model. Subsequently, the Lyapunov method was adopted to design the trajectory tracking control algorithm, and the joint angles collected in the steepest discrete tracking differentiator were fed into the control algorithm to calculate the real-time compensation. The compensation value was then applied in the robot, which effectively achieving friction compensation. The proposed algorithm was validated by employing a six-degree-of-freedom serial robot as an experimental subject. The results demonstrate that the trajectory tracking error is reduced by approximately 35%, as comparing with that under the non-compensation conditions, which confirms the efficacy of the algorithm in the realm of robot friction compensation.

Model Feedforward Compensation Active Disturbance Rejection Control for a Heavy-Duty Hydraulic Manipulator Arm



GUO Xinping, HE Xin, WANG Hengsheng, et al

2024, 52(4):  59-67.  doi:10.12141/j.issn.1000-565X.230115

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Hydraulically-driven heavy-duty manipulator arms are widely used in construction and mining machinery, and there is an urgent need for its automatic control in the industry. However, the strong parametric uncertainties and difficult-to-model dynamics of the hydraulic system and other factors bring certain challenges to its automatic control. This paper studied the position tracking control problem of a class of heavy-duty hydraulic manipulator arm driven hydraulic cylinders by taking an anchor drilling truck as an example, and proposed a model feedforward compensation active disturbance rejection controller. To solve the control problems caused by nonlinear factors such as variable load, dead zone, parametric uncertainties and friction under heavy loads, the study adopted the control method of combining model feedforward and active disturbance rejection feedback, and established the mechanism model of the system by combining the mechanism dynamics model of the heavy-duty hydraulic manipulator arm and the model of proportional valve-controlled hydraulic cylinders. Then based on the mechanism model of the system, it constructed the feedforward compensation part of the controller, and designed an extended state observer to observe the unmodeled factors of the system in real time, and the active disturbance rejection controller was constituted together with the feedback adjustments based on the state error. The experimental studies were carried out on a real heavy-duty hydraulic manipulator arm, and the results show that the model feedforward compensation active disturbance rejection controller has smaller hysteresis and tracking error than PID controller, and the overall tracking accuracy is improved by 63.5% compared with that of PID controller. This indicates that the designed controller can overcome the adverse effects of the nonlinear factors of the hydraulic system very well, and it has a higher robustness than the PID controller. Therefore, the designed control method is more suitable for the position tracking control of this kind of heavy-duty hydraulic manipulator arm.

Application of Compressed Sensing in Sound Intensity Imaging of Bent-Axis Motor



CHEN Shumei, LUO Yuanming, HUANG Hui, et al

2024, 52(4):  68-76.  doi:10.12141/j.issn.1000-565X.230328

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The internal noise sources of the bent-axis piston motor are close in distance. For example, the distance between the inlet and outlet of the motor valve plate is 38 mm, and the noise sources have the same frequency and multiple frequency phenomenon. The dense and complex noise sources in the bent-axis motor cause difficulties for the spectrum analysis method to accurately identify the same frequency and multiple frequency signals. The maximum resolution of traditional sound intensity measurement is 50 mm, which cannot meet the requirement of identification accuracy of motor internal noise source. Aiming at the problem that the traditional methods are difficult to identify the motor noise sources accurately, this paper proposed a sound intensity measurement method based on compressed sensing. The compressed sensing theory was applied to the high-precision reconstruction of sound intensity image to obtain the high-resolution sound intensity reconstruction image of the motor. Firstly, the noise radiation simulation of the bent-axis motor was carried out to obtain the characteristics of its external surface sound field. Then, based on the sound intensity image for the motor, a compressed sensing frame applied to the motor sound field was designed to obtain the sound intensity cloud image of the motor with high precision. Finally, the feasibility of the compressed sensing theory to improve the identification accuracy of motor noise source was verified by comparing the traditional acoustic intensity measurement with the compressed sensing acoustic intensity measurement. The results show that the identification scale of motor noise sources are improved from 70 mm to 30 mm by the sound intensity measurement method based on compressed sensing, which improves the accuracy of motor noise sources identification and realizes the high precision location of motor noise sources.

Influence of Cycloidal Pinwheel Reducer Parameters on Transmission Efficiency and Parameter Optimization



ZHANG Yueming, LI Tianyu, JI Shuting

2024, 52(4):  77-87.  doi:10.12141/j.issn.1000-565X.230259

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In order to further improve the transmission efficiency of the cycloidal pinwheel reducer, this study conducted in-depth research on the influence of the reducer transmission efficiency. It proposed a calculation model for the transmission efficiency of the cycloidal pinwheel reducer that takes into account changes in design parameters and working condition parameters and optimized the parameters. Firstly, considering the friction force and meshing backlash, the study established a multi-tooth load-bearing contact analysis model of the cycloid pinwheel transmission mechanism, and calculate the meshing force and load distribution pattern of the cycloid pinwheel gear. Then, considering the engagement loss, output loss, bearing loss, lubrication loss and sealing loss, this paper proposed a calculation model for the transmission efficiency of the cycloidal pinwheel reducer, and analyzed the influence of the design parameters and working condition parameters on the transmission efficiency of the cycloidal pinwheel reducer. Research shows that, taking frictional stress into account, rotation speed, load, pin tooth pin radius, pin tooth distribution circle radius, eccentricity, and pin tooth sleeve radius are the main parameters that affect transmission efficiency, followed by the number of pin teeth, pin distribution circle radius, pin radius and cycloid tooth width. Finally, the optimal parameter solution was obtained through a multi-objective optimization analysis of the design parameters with gear strength, gear width, tooth profile shape, inter-tooth clearance and load-bearing capacity as the parameter optimization range, and transmission efficiency and volume as the goals. And then a smaller volume and more efficient cycloidal pinwheel reducer was obtained.

Effects of the Wear of Fabric Liner on Self-Lubricating Joint Bearings Dynamics



HAO Xiuhong, TIAN Runwei, JIAO Wei, et al

2024, 52(4):  88-94.  doi:10.12141/j.issn.1000-565X.230211

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In the service process of self-lubricating joint bearings, the wear of the liner leads to the gap between the inner and outer rings of the self-lubricating joint bearings. The existence of the clearance of the self-lubricating remote pair accelerates the collision between the inner and outer rings and further wear of the liner, which has a great impact on the dynamic characteristics of the self-lubricating joint bearings. In addition, the wear of the liner will also lead to the deterioration of the nonlinear characteristics of each component and reduce the stability of self-lubricating joint bearings. In order to study the effects of the wear of the self-lubricating liner on the dynamic response of the self-lubricating joint bearing, this study established the kinematic subvector model of self-lubricating joint bearing with clearance. Firstly, it modeled the collision force at the gap between the inner and outer rings by modifying the Lankarani-Nikravesh (L-N) normal contact force model and improving the Coulomb friction force model. Then, based on Newton’s second law, it established the rigid-flexible coupling dynamic equation with gap. Finally, it analyzed the dynamic characteristics of the drive system of the self-lubricating knuckle bearing with clearance under different wear amount and friction factor. And it also analyzed the nonlinear characteristics of the self-lubricating knuckle bearing by using phase diagram and Poincare mapping diagram. The results show that the dynamic behavior of the inner and outer rings of the self-lubricating joint bearing exhibits nonlinear characteristics with the increase of the wear amount of the fabric liner. When the wear amount is certain, the stability of the system is improved with the increase of the friction factor of the liner, and the occurrence of chaos is suppressed.

Traffic Safety

Safety of Existing Intersection High-Speed Railway Trains Under the Condition of Sheild Tunnel Penetration Construction Considering the Stochastic Field



TANG Qianlong, PENG Limin, DENG E, et al

2024, 52(4):  95-103.  doi:10.12141/j.issn.1000-565X.230062

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In view of the problem that the subgrade soil is often regarded as a medium with deterministic parameters in the traffic safety analysis of high-speed railway in subgrade section. In this paper, based on the stochastic field theory, subgrade soil was regarded as a three-dimensional medium with longitudinal uniformity, and a numerical model was established for a shield tunnel penetrating below an existing high-speed railway line. The parameter randomness of the subgrade soil cross section was simulated based on the number theory point selection method. In order to further explore the impact of a penetration shield tunnel on the safety of the existing high-speed railway, a 31-DOF vehicle model was established in this paper. Combined with the Fluent 3D fluid simulation software and dynamic grid technology, the aerodynamic load time history curve of high-speed train was obtained, and the derailment coefficient and probability density evolution information of trains at speeds of 300, 350 and 400 km/h were analyzed based on the probability density evolution theory. The results show that the existence of stochastic field makes the wheel weight reduction rate and derailment coefficient present a certain probability distribution range. The vertical wheel-rail force curve fluctuates obviously under the influence of the aerodynamic load and the subgrade deformation caused by the tunnel penetration. The maximum load reduction rate of wheel weight appears in the descending section on both sides of the maximum surface settlement. The vertical aerodynamic load is greater than the transverse aerodynamic load. With the increase of vehicle speed, the upper limits of wheel weight reduction rate and derailment coefficient are gradually increasing. In order to ensure the safety of intersecting trains, it is recommended that the running speed of high-speed trains under the shield tunneling should not exceed 300 km/h.

Lane-Changing Trajectory Planning Strategy for Autonomous Vehicles on Superhighways



HE Yongming, XING Wanyu, WEI Kun, et al

2024, 52(4):  104-113.  doi:10.12141/j.issn.1000-565X.230339

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To improve the driving safety of autonomous vehicles on superhighways, this paper proposed a lane-changing trajectory planning strategy. Firstly, five polynomials were used to generate general lane-changing trajectory clusters, and the trajectory planning problem was quantified as the duration of solving lane-changing behavior with the limit of vehicle dynamics and surrounding traffic vehicles. Then, considering the constraints of vehicle dynamics, the vehicle dynamics model and Brush tire model were established. Based on the tire lateral force data of the established vehicle model, the tire lateral stiffness was solved, and the magic tire model was used to verify the tire lateral stiffness. Next, the phase plane of sideslip angle and yaw rate was introduced to obtain the safe driving envelope of high-speed vehicle. CarSim simulation training was carried out on given multiple groups of vehicle speeds and adhesion coefficients to determine the shortest lane-changing time that meets the vehicle dynamics constraints. Finally, considering the collision avoidance constraints with surrounding traffic vehicles, three typical lane-changing scenarios were analyzed. The shortest and longest lane-changing durations satisfying the collision avoidance requirements were determined based on the position of single obstacle vehicle, and the threshold model of lane-changing duration satisfying the safe lane-changing requirements was established. The multi-parameter safety lane-changing domain test shows that the established vehicle safety lane-changing duration boundary model can solve the safe and feasible lane-changing trajectory under the given parameters, provide trajectory reference for the superhighway lane-changing behavior, and improve the safety of the superhighway lane-changing behavior.

Effect of Connected HUD Warning System on Driving Behavior for Pedestrian Crossing Events



BIAN Yang, ZHANG Yu, ZHAO Xiaohua, et al

2024, 52(4):  114-125.  doi:10.12141/j.issn.1000-565X.230096

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In order to demonstrate the effectiveness of the warning system, this study explored the influence of the head up display warning system on driving behavior under different weather conditions in the connected environment for pedestrian crossing events. Firstly, this paper designed three warning systems: baseline, head down display (HDD), and head up display (HUD). Based on the driving simulation platform, it developed connected scenarios of urban roads under clear and foggy weather conditions and extracted driving behavior parameters through experimental testing. Then, from the micro level, the paper described the whole spatial change process of driving behavior under the action of connected HUD warning system for pedestrian crossing events, analyzed the influence rules of the warning systems and weather conditions on driving behavior, and constructed the influence model of driving behavior including risk avoidance stage and recovery stage. Next, a comprehensive index system was proposed to reflect the safety level at the risk avoidance stage, the recovery level at the recovery stage and the stability level of the whole process, including the first braking distance, the minimum conflict distance, the recovery stabilization time, the recovery amount of velocity, the maximum deceleration and the maximum acceleration. Finally, it quantified the effects of different warning systems (Baseline/ HDD/ HUD), weather conditions (clear weather/ foggy weather) and the interaction between the two factors on driving behavior. Research shows that the connected HUD warning system for pedestrian crossing events has a significant effect on drivers’ driving behavior in the risk avoidance and recovery stage, and it significantly improves the safety level of driving behavior in the risk avoidance stage. At the same time, it has a significant improvement effect on the recovery efficiency during the recovery stage, and also significantly affects the stability level of the operational characteristics throughout the whole process. The connected HUD warning system for pedestrian crossing events shows more obvious advantages under foggy conditions.

Online Driving Style Recognition Method Considering Lane-Changing Game

ZHANG Yunchao, HUANG Jianling, LI Yongxing, et al

2024, 52(4):  126-137.  doi:10.12141/j.issn.1000-565X.230159

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Driving style is the external expression of driving behavior. Drivers with aggressive style tend to engage in more frequent risky driving operations, intensifying interactions between vehicles and affecting lane-changing safety. Identifying a driver’s driving style before executing a lane-changing can effectively constrain driver’s behavior through personalized warning information. This paper proposed the SHAP-XGBoost method, which considers lane-changing game in a connected environment, aiming to achieve the real-time recognition of driving styles during the lane-changing intention phase. Firstly, the fluctuation degree of individual behavior and gaming behavior during the lane-changing intention was used as input feature variables, and the driving style was marked by correlation analysis, principal component analysis, and four different clustering methods. Next, the proposed SHAP-XGBoost model was used to select key features for training the driving style recognition model, and online recognition was completed through a sliding window. Finally, experiments were conducted using the HighD dataset. Results show that: compared with clustering methods based on centroid distance, connectivity and density distribution, spectral clustering based on graph theory principles can better label driving styles based on the morphology of the input feature variables; using the proposed SHAP-XGBoost model with 14 key features for driving style recognition can improve online recognition efficiency without loss of accuracy, and the driving style recognition accuracy is up to 99%; simultaneously incorporating individual features and gaming features as inputs to the model can improve the accuracy of driving style labeling and recognition. The research results can be used to support personalized lane-changing decisions and early warnings.

Identification of Hazardous Driving Hotspots of Conventional Urban Bus Based on Spatial Autocorrelation



ZHANG Wenhui, LIU Tuo, SONG Yajing, et al

2024, 52(4):  138-150.  doi:10.12141/j.issn.1000-565X.230026

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In order to obtain the spatial distributing characteristics of hazardous bus driving status, this paper identified the spatial clustering through spatial autocorrelation analysis, determined the hot spots, and analyzed the significant influencing factors. Firstly, the study collected position system data samples of the urban buses for one week in each of the four quarters and modified the duplicate, abnormal and missing data. Bus stops were used as nodes to divide spatial spots, and every spot was numbered. Over speed, urgent acceleration, urgent deceleration and sharp turn were identified as hazardous driving status. The four conditions thresholds were obtained according to the kinematic characteristics of vehicles. The study calculated statistical indicators and global Moran’s I_g of four conditions. The results show that hazardous driving status are spatially clustered (probability of a spatial random distribution p < 0.01, standard deviation score Z > 2.58). Over speed has most significant characteristic of spatial clustering (I_g = 0.731). The study performed local spatial autocorrelation analysis for the four conditions. According to the analysis, local Moran’ s I scatter plots and LISA clustering plots are plotted at 90%, 95% and 99% confidence levels. The hazardous hot spots of urban buses were obtained combining with city maps. Finally, the study selected 9 factors such as road length, number of lanes and straightness to formulate models. The compare and analysis were performed to get the fitting goodness of OLS, SLE, SEM and SDM model. The SDM model was used to obtain the significant influencing factors for 4 dangerous driving states. The results can provide a theoretical basis for supervising the safety operation and identifying the hazardous driving status of urban buses in spatial perspective.