Table of Content

25 November 2020, Volume 48 Issue 11

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Traffic & Transportation Engineering

Double Iterative Afloat Condition Calculation Method for Convex Polyhedron Composite Structure



LIU Xiao, XU Lei, FAN Tianhui, et al

2020, 48(11):  1-9.  doi:10.12141/j.issn.1000-565X.200039

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A new method for calculating the afloat condition of convex polyhedron composite structure was pro-posed． Firstly，the afloat object was meshed by the tetrahedra，and then the water plane equation was calculated by the double iterative method，which consists of the inner and outer iterative procedures simulating the heaving and rotation motions of the afloat object respectively． The afloat condition experiment was carried out for a semi-submersible offshore platform． The algorithm proposed in this paper was also compared with Maxsurf which is the famous computer aided ship design and construction software． The experimental and comparative test results show that the method has clear physical meaning，the corresponding algorithm is accurate and reliable with good conver-gence． This new method is more suitable for analyzing the afloat condition of the convex polyhedron composite structure than the traditional method．


Study on Testing Mechanism and Application of Tension under Anchor for External Prestressing Strand by Ｒeverse Tension Method



GUO Wenlong SHAN Chenglin LIANG Peng

2020, 48(11):  10-18.  doi:10.12141/j.issn.1000-565X.200173

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In view of the lack of reliable testing methods for the effective tension of end anchor of external prestressed strand，the mechanical mechanism of testing the tension of end anchor by the reverse tension method was revealed based on the mechanical mechanism of mechanical equilibrium and deformation coordination． And the theoretical testing error under the most unfavorable conditions was analyzed，and the applicable conditions of the method were pointed out. Finally，based on the most commonly used construction machines and equipment in the construction site，a practical test method and system composition were put forward and verified on the indoor static load anchorage test machine． The test results show that the sensitivity of different parameter curves in judging tension force under strand anchor is:  forcedisplacement  curve ＞ force-time curve ＞ displacement-time curve． The test accuracy of the proposed method can meet the requirements of engineering accuracy．


Crash Risk Evaluation Model Based on Brake Heating for Trucks under Continuous Downhill Road Conditions



ZHANG Chi, HU Tao, HOU Yudi, et al

2020, 48(11):  19-29.  doi:10.12141/j.issn.1000-565X.200072

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An innovative model based on brake heating for crash risk evaluation was proposed to quantitatively evaluate the driving risk of trucks on continuous downhill． First，considering the risk of chain accidents caused by the continuous reduction of truck braking performance，the brake heating of the brake hub was used to represent the key risk cause of the crash accidents，and the truck accident rate was used to represent the risk accident.Then，taking the continuous downhill in Ya'an-Xichang section of Beijing-Kunming highway as the research section，the risk cause and risk accident were quantified by numerical simulation of the brake heating，and the inner connection between braking temperature, temperature gradient and accident rate was revealed by correlation analysis.Finally，the crash risk measurement equation was constructed by using multiple nonlinear regression method to fit the surface function，and the crash risk evaluation model was established in combination with the risk classification criteria． The results show that the Cumulative Logistic function can better explain the changing law of the truck crash risk on downhill． The average error between the final model evaluation result and the actual accident is 0. 288，and the accuracy rate is 80. 87%． The evaluation model shows high accuracy and can provide reference for scientific decision-making in traffic safety management and control of continuous downhill sections．


Research on the Comprehensive Influence of Navigation BroadcastWording on Driving Behavior



BIAN Yang, YU Jie ZHAO, Xiaohua, et al

2020, 48(11):  30-37,54.  doi:10.12141/j.issn.1000-565X.190913

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In order to reduce the traffic accident caused by the deviation of the driver under the complicated road conditions and to improve the driving safety，the exits of urban expressway with five forks were taken as the research object． Based on the driving simulation technology，the driving behavior data was obtained and evaluated with six indicators． The driver's behavior was analyzed from the aspects of driving efficiency and stability under different navigation broadcast wording． The TOPSIS evaluation method was used to select out the optimal broadcast wording． The results show that different navigation broadcasts have different influence on the driving behavior at the five forks of urban expressway． The driving behavior under navigation broadcasts with a moderate amount of information is efficient and stable，and the driving behavior is the worst under navigation broadcasts with too little information．This result indicates that the navigation information needs to be moderate． Broadcasts with little information can easily lead to confusion，while broadcasts with too much information will increase the information load．Both confusion and the increase in information load have a negative impact on driving behavior． This study can provide guidance for the design of the navigation broadcast wording in urban expressways with multiple forks．



Multi-type Bus Timetable Optimization Considering Unbalanced Passenger Flow in Time and Space



HU Baoyu PANG Yu PEI Yulong

2020, 48(11):  38-48.  doi:10.12141/j.issn.1000-565X.190887

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A multi-type bus timetable optimization method based on the rule of passenger flow change was put forward in order to solve the problem of mismatch between supply and demand caused by unbalanced passenger flow in time and space． The objective function and constraint conditions of the model were determined from the perspectives of bus company and passengers，and the multi-objective optimization model of bus model was established．Graph theory was introduced，and feasible timetable was regarded as branch (path)． Feasible timetable set of public transport vehicles was represented by tree diagram． Public transport operation was described with vehicle space-time track diagram and cumulative passenger flow diagram． Based on this，feasible timetable，vehicle type combination and corresponding departure interval of each branch were determined，and waiting time and other target values of each branch were calculated． Then the multi-objective Pareto optimal solution (optimal schedule) of the model was solved by using the multi-objective K shortest path idea． Finally，the case data (No． 18 bus in Harbin) was calculated and compared with the multi-type bus configuration model with a single target fixed departure interval． The results show that the optimization can effectively reduce the line passenger capacity (30% in this case) and improve the service level of public transport under the condition of low operating cost.


Mechanical Engineering

Parameter Estimation Method Based on Minimum Cumulative Error Square Sum



ZHANG Yingzhi, ZHAI Fenli, ZHENG Yubin, et al

2020, 48(11):  49-54.  doi:10.12141/j.issn.1000-565X.200159

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When using classical least squares and weighted least squares to estimate the two-parameter Weibull model parameters，it satisfies the unbiasedness well but it doesn't satisfy the validity． Aiming at this problem，a parameter estimation method based on the minimum sum of squared cumulative errors was proposed． The parameters were calculated for full samples，time-censored samples，and fixed-number censored samples． The root mean square error was used as an indicator to evaluate the effect，and an empirical study was carried out in conjunction with relevant literature data． The research shows that the ＲMSE value of the proposed parameter estimation method is small than that of the least squares and weighted least squares，so it can efficiently estimate the parameters of the two-parameter Weibull model．


Design and Analysis of Quasi-zero Stiffness Hydropneumatic Suspension System



ZHANG Xiaojiang YAN Zhenhua

2020, 48(11):  55-63,79.  doi:10.12141/j.issn.1000-565X.200107

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A new type of hydropneumatic suspension system was designed based on the traditional hydropneumatic suspension． The stiffness of the new suspension at the origin position can be adjusted，and theoretically the stiffness of suspension can be positive，zero or even negative． A matching design method and boundary for the suspension parameters at the origin were given for the new hydropneumatic suspension system when the suspension has zero stiffness at the origin position． The stability conditions of the new suspension system at the origin position was analyzed． The phase diagrams of the new suspension system under the free vibration conditions in balance position was obtained without damping，and the nonlinear relationship between the free vibration frequency and the amplitude of the suspension was obtained． This research enriches the design theory of hydro pneumatic suspension and provides a new design method for the design of hydropneumatic suspension．


Research on Buffeting Noise Characteristics of Automobile Side Window



HU Xingjun, ZHANG Yanghui, GUO Peng, et al

2020, 48(11):  64-71.  doi:10.12141/j.issn.1000-565X.200119

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Based on the LES method，the buffeting noise characteristics of automobile side window was studied with the DSLM subgrid-scale model． The simulation method was verified through the comparison of experimental data，and the buffeting noise characteristics of different opening degrees of side windows，different combinations of opening modes，crosswinds and the number of passengers were also studied． The research results show that: the SPL and frequency of buffeting noise increases with increase of the vehicle speed; the side window has lower buffe-ting noise at a small opening degree and higher buffeting noise at a large opening degree; the buffeting noise under the positive yaw angle is lower than the negative yaw angle; the number of passengers has a limited impact on the buffeting noise．


Simulation and Optimization of Water Contamination on Automotive Side Window



XIN Li HU, Xingjun, ZHANG Jinglong, et al

2020, 48(11):  72-79.  doi:10.12141/j.issn.1000-565X.200126

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In order to reduce the water contamination on side window of vehicle running in the rain and improve driving safety，an water contamination optimization design of side window was carried out based on the boundary seeded domain method and automatic optimization design method． The parameters of the A-pillar section were se-lected as design variables，and the sample space was constructed using orthogonal test design． The droplet trajec-tory and water covering area on side window were calculated by combing lattice Boltzmann method，the Lagrangian particle motion model，the liquid film model and boundary seeded domain method． The approximate relationship between the design variables and the contaminated area was fitted by the Kriging model． Multi-island genetic algo-rithm was used to get the minimum area of side window water contimination． The results show that the area of water contamination in the side window of the optimized model decreases by 66. 2%．


Research on Dynamic Characteristics of a Double Roller Tripod Joint



QIU Yinyuan, ZHEN Ran, LI Ruilong, et al

2020, 48(11):  80-86.  doi:10.12141/j.issn.1000-565X.200199

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The multi-body dynamic model of a double roller tripod joint was established，and the dynamic forces generated during its working process were analyzed． The generated axial force and high frequency plunging force were tested，and the comparison between the calculation results and the test results verifies the correctness of the model． Based on the established model，the dynamic characteristics of a tripod joint and double roller tripod joint were compared． The results show that the axial generated force of a double roller tripod joint is reduced by 80%，and the high frequency plunging force is reduced by 50%．


Computer Science & Technology

Partial Multi-view Clustering Based on StarGAN and Subspace Learning



LIU Xiaolan YE Zehui

2020, 48(11):  87-98.  doi:10.12141/j.issn.1000-565X.200128

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The traditional multi-view clustering method assumes that the data of each view is complete． However，there is a lack of data in some views in real life，and thus leads to the problem of partial multi-view clustering．Most of the existing partial multi-view clustering methods are based on kernel matrix and non-negative matrix de-composition，and most of them are just learning a common clustering structure，rather than making full use of the existing data information to infer the missing data． Based on StarGAN and subspace learning，a partial multi-view clustering algorithm (SSPMVC) was proposed in this study． SSPMVC makes full use of the existing data informa-tion to generate the missing data with the generation model based on StarGAN，captures the integrity and consisten-cy global structure of the data，and then clusters the completed multi-view data in the subspace． The generation model and clustering model were trained jointly by SSPMVC，and the generation model and clustering model were alternately optimized． The experimental results show that the algorithm proposed in this paper is superior to the classical multi-view clustering method．


Improved Transfer Learning Algorithm Based on Cross-domain in Recommendation System



ZHANG Ziye, LI Mingchang, LIANG Lingrui, et al

2020, 48(11):  99-106.  doi:10.12141/j.issn.1000-565X.190619

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In recommendation system，the single-domain recommendation algorithm faces many practical prob-lems． The main collaborative filtering algorithms only use the information of the interaction between users and i-tems，and can not avoid the problem of data sparsity in practical applications． This study focuses on the fusion of information from other fields to deal with sparse data，and solve the problem that it is difficult to find effective asso-ciation from cross-fields． An associative feeling network model based on the deep neural network was proposed． It realizes transfer learning by mining the content information and information of items to obtain the optimal feature as-sociation，thus the accuracy of recommendation was optimized． The algorithm can deal with the problem of data sparsity in the recommendation system． Compared with some recently proposed algorithms，it shows an improved performance (15% ～20%) and better expansibility．


Short-term Traffic Flow Prediction Based on Temporal Convolutional Networks



YUAN Hua CHEN Zehao

2020, 48(11):  107-113,122.  doi:10.12141/j.issn.1000-565X.190276

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Short-term traffic flow prediction is the key for Intelligent Transport Systems (ITS) to achieve traffic control and traffic guidance． Traditional convolutional neural networks are difficult to obtain long-term memory in short-term traffic flow prediction，and there is information “leakage”from future to past． Dilated-Causal Fully Convolutional Networks (DCFCN)，which introduces dilated convolutions to increase the reception field and ob-tain long term memory of sequences，was proposed in this study． At the same time，the causal convolutional was introduced into DCFCN to solve the problem of information“leakage”． DCFCN is composed of 6 convolutional la-yers，each layer achieves causal convolution by padding，and the dilated increases exponentially with the depth of the network． Experiments show that the proposed DCFCN is superior to other comparison models in short-term tra-ffic flow prediction，and the computational efficiency on the GPU is significantly improved．


Research on SDN Topology Attack and Its Defense Mechanism



LU Yiqin, MAO Zhongshu, CHENG Zhe, et al

2020, 48(11):  114-122.  doi:10.12141/j.issn.1000-565X.200282

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A SDN topology attack defense mechanism———PolicyTopo was proposed in order to protect the view se-curity of the controller in software-defined networking (SDN)，especially the global view integrity in the context of network link state changes． This mechanism introduces information entropy theory to build a model to verify the change of network link delay，and at the same time defines the security of data device ports． It also solves the de-fense problem of topology attacks under network state changes while defending against traditional topology attacks．PolicyTopo was deployed both on the virtual environment and the physical experiment platform，and the offensive and defensive tests were carried out based on Floodlight． The results show that PolicyTopo can dynamically and ef-fectively protect the topology integrity during network state changes and improve the security of the global view of the network． Compared with other mainstream defense mechanisms，this mechanism can largely reduce the cost of network resource and improve the security，flexibility and scalability of the network．


Food Science & Technology

Study on Interaction between Heterocyclic Aromatic Amines and Bovine Serum Albumin



LI Lin, WU Ming, LI Bing, et al

2020, 48(11):  123-130.  doi:10.12141/j.issn.1000-565X.200285

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Heterocyclic aromatic amines (HAAs)，as a kind of carcinogenic substance，is mainly generated in the thermal process of foods． The study of its interaction with transport proteins is important for revealing its toxicity in human bodies． The interaction between two common heterocyclic aromatic amines as 2-amino-3-methylimidazole［4，5-f］-quinoline (IQ)，9H-pyrido ［3，4-b］indole (Norharman) and bovine serum albumin (BSA) was studied with multi-spectroscopic methods． It shows that both heterocyclic aromatic amines can be spontaneously combined with BSA to quench the endogenous fluorescence，and the binding site is about one for both heterocyclic aromatic amines． The quenching mechanism of IQ to BSA is a combination of dynamic and static quenching，in most cases dynamic quenching is dorminant． The molecular interaction between IQ and BSA is mainly driven by a hydrophobic force． The quenching mechanism between Norharman and BSA is the static quenching of ground state complex formation，and the binding is driven by hydrogen bonding and van der Waals force． Both IQ and Norhar-man can cause the changes of BSA conformation，and the degree of conformational change caused by IQ is higher than that of Norharman． In addition，according to the principle of minimum energy，the binding site of HAAs and BSA was simulated by molecular docking．


Effect of Microwave Pre-expansion Process on the Quality of Highland Barley Chiffon Cake



RUAN Zheng, ZHANG Chi, LI Dandan, et al

2020, 48(11):  131-138,146.  doi:10.12141/j.issn.1000-565X.190369

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Under the traditional hot air baking conditions，the chiffon cake，which is made of high highland bar-ley powder，is difficult to expand and easy to produce wet flesh inside． Besides，it has other problems such as un-stable product structure，rough taste and so on． To solve these peoblems，the effect of microwave pre-expansion combined with hot air baking on the quality of highland barley chiffon cake was discussed． The main indexes in-clude moisture content，specific volume，sensory quality，texture，color，and internal stomata shape of cake．The results show that microwave (800 W) pretreatment for 20 s can make the highland barley batter rapidly ex-pand to the maximum volume point，and then after hot air baking for 35 min，the cooked cake will show fine struc-ture，high stomata density and uniform distribution． Compared with the pure hot baking (170 ℃，50 min) and pure microwave curing (800 W，95 s)，microwave pre-expansion process can improve the specific volume，rough feeling and internal viscosity of the cake． In addition，the cake baked with microwave pre-expansion process is better than pure microwave curing cake in appearance，color，texture，mouthfeel，stomata pore distribution u-niformity and the cavity wall uniformity．


Effect of Pulsed Electric Field Treatment on Kumquat Texture and Its Mechanism



ZENG Xinan, ZHOU Lizhen, LIN Songyi, et al

2020, 48(11):  139-146.  doi:10.12141/j.issn.1000-565X.200139

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As a high-efficiency non-thermal processing technology，pulsed electric fields (PEF) can be applied in drying，extraction，sterilization，and immersion procedures of food production． The influence of PEF pretreatment on the texture characteristics of kumquat from the perspective of physical properties (hardness，chewiness，elastic-ity，etc． ) was studied in this article． Moreover，the reasons resulting in the quality change of kumquat were dis-cussed． Experimental results show that the crystallinity of kumquat cellulose decreases and the distance between chains increases when the PEF treatment intensity is between 1. 0 to 2. 0 kV/cm，thus the structure become looser which leads to the decrease of hardness and chewiness． When the hemicellulose structure collapses，molecular chain become shorter，and hydrophilicity and swelling property are improved，resulting in better elasticity． The re-duction of molecular weight of pectin leads to the decrease of kumquat's hardness and adhesion． This study can pro-vide guidance for the improvement of immersion and maceration process in food industry．