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    Decision-making Forum
    Serving for Xiong’an New Area and Innovation of Traffic Photoelectric Network
    PENG Hong-qin, ZHANG Guo-wu
    2018, 18(4): 1-4. 
    Abstract ( )   PDF (2625KB) ( )  

    Xiong’an New Area as bearing land for untwining non capital function of Beijing, it will be built to a high level socialist modern city, an important part of a world-class city cluster on Beijing, Tianjin and Hebei, a new engine of the modern economic system, and a national example of promoting high quality development. The 51st conference of “Traffic and Transportation 7+1 Forum” sets its theme as “Serving for Xiong’an New Area and Innovation of Traffic Photoelectric Network”. Photoelectric network is reliable, security and steady basic network for constructing Xiong’an New Area, building smart city and intelligent transportation. According to the technical features of new energy and renewable energy, physical network and internet fusion platform of energy is built base on the energy internet, so that the efficiency of the whole energy system can be optimized. The analysis shows that distributed optical fiber sensing technology can provide strong support for intelligent detection and disaster warning of infrastructure such as city pipe network and roads.

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    Public Service Protection Constrained Railway Seat Inventory Control Policy
    HAN Shu-yi, RONG Chao-he
    2018, 18(4): 5-10. 
    Abstract ( )   PDF (3233KB) ( )  

    The passenger transportation of normal-speed railway contains the profitable service and public service. Distinguishing these two services is good for both fair and profitable objection. Based on the asymmetric transshipment model, this paper provides a policy named separated and delay transferred seat allocation (SDP). That is the seat is allocated to profitable and public service at the beginning of sale period. Before the time of departure, e.g. 24 hours, the unsold public service seat can be transferred to profitable market. This policy also introduces the service-percentage-constraint (SPC) to protect public service demand and the capacity constraint. The results show that SDP can improve the profit and SPS at the meantime.

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    Forum about Comprehensive Transportation System
    A Green Intermodal Transportation Stochastic Optimization Strategy
    LI Jun, YANG Bin, ZHU Xiao-lin
    2018, 18(4): 11-18. 
    Abstract ( )   PDF (4753KB) ( )  

    This paper researches on the green intermodal transportation routing planning strategy with traveling speed obeying stochastic distribution. A green intermodal stochastic optimization model is established by using stochastic optimization method. A hybrid method of combining sample average approximation and particle swarm optimization based on priority is designed for solving this model. In numerical experiments, a simper case is designed to test the model reliability and accuracy, and analyzes a set of scenarios such as the normal distribution and uniform distribution of the speed, and the carbon emission factor. According to the actual situation, it is concluded that when the size of the sample is 600, the situation 3-4 transportation cost is 501.11 and the carbon emission cost is 649.07 is the ideal decision with high stability. When the carbon emission factor increases to 0.8, the cost is reduced. Experiments results show that the proposed stochastic optimization model can deal with the problem of intermodal transport path optimization under uncertain and can provide decision support for intermodal transport operation manager.

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    Total Factor Productivity of China Airlines under Carbon Emission Constraints
    HUANG Gan-xiang, JING Chong-yi, WANG Hong-yan
    2018, 18(4): 19-24. 
    Abstract ( )   PDF (3538KB) ( )  

    To study the total factor productivity growth of China airlines and its influencing factors under carbon emission constraints, this paper uses CO2 emissions as undesirable output and applies the GML index to estimate the total factor productivity and its dynamic changes of China airlines during 2009-2013, and then analyzes the influencing factor with panel data model. The results show that: ignoring CO2 emissions will significantly overestimate the growth of China airlines TFP and cannot get the true productivity growth; The TFP growth is mainly due to the improvement of technical efficiency during the investigation; The TFP growth under the carbon emission constraints has a significant negative correlation with the fuel consumption of per ton-kilometer, and improving fuel efficiency is the most remarkable and effective way to promote its growth; Besides, the TFP growth is positively correlated with the aircraft utilization, while negatively correlated with the flights, and has no significant correlation with the average distance and the private property.

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    Dominant Transportation Distance for Multi Transportation Modes in Urban Integrated Transportation Network Based on General Travel Costs
    2018, 18(4): 25-31. 
    Abstract ( )   PDF (3406KB) ( )  

    In order to study the structure of urban integrated transportation network and help policymakers to allocate urban traffic resources reasonably, the probability density curve of the dominant travel distance of each mode of transport based on the generalized travel cost in urban comprehensive traffic network is studied. Analysis of the general travel costs for residents’ travel (which is the service level of transport modes, including travel time, fares and comfort levels) can determine the average costs of travel modes in the city. The probability density curve of travel distance with different transport modes in the same travel network is constructed, and the probability density model of urban transport modes based on generalized travel cost can be obtained by analyzing and fitting the probability density curve. Finally, Nanjing is taken an empirical analysis as a case study.

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    Connectivity Reliability of Nodes in the Maritime Transportation Network of Crude Oil Based on Vine Copulas
    WANG Shuang, LV Jing, LAI Cheng-shou
    2018, 18(4): 32-37. 
    Abstract ( )   PDF (3608KB) ( )  

    To evaluate the connectivity reliability of key nodes under the effect of correlative extreme events in the maritime transportation network of crude oil, the vine copula is proposed to construct the joint probability distribution, and the connectivity reliability is evaluated based on the joint and conditional probability distribution. Finally, the Strait of Malacca is illustrated as a case study. The results show that there is a symmetric tail dependence between the political instability or military conflict and the pirates and maritime terrorism. While there is a lower tail dependence between the pirates and maritime terrorism, the vessel accidents and the heavy weather, respectively. Besides, under the effect of political instability or military conflict, heavy weather and pirates and maritime terrorism, the connectivity reliability of the Strait of Malacca is low, which is only 0.239 5. While under the effect of political instability or military conflict, heavy weather and vessel accidents, the connectivity reliability is relatively high.

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    Intelligent Transportation System and Information Technology
    High Accuracy Vehicle Localization by Referring to Pavement Fingerprint
    WANG Xiang-long, HU Zhao-zheng, LI Yi-cheng, HUANG Gang, CAI Hao
    2018, 18(4): 38-45. 
    Abstract ( )   PDF (5326KB) ( )  

    Visual based localization methods are widely used in vehicle localization. Since the forward and lateral views are susceptible to environmental change and traversing images of mapping data is time-consuming, this paper proposes a new down-view image-based presentation model: pavement fingerprint. The pavement fingerprint contains GPS(Global Positioning System), pavement feature and image feature points. It applies CNN (Convolutional Neural Network) and connect region to recognition the pavement feature of query image. It uses pavement feature to narrow the range of candidate map nodes which are filtered by GPS coarse localization. It improves efficiency of localization. In the experiment, the pavement fingerprint has been tested on the roads with dense pavement feature and road with sparse pavement feature, respectively. The results show that by utilizing the pavement fingerprint, the time consuming for localization reduced by 20.3% and the average localization error is 47.4 mm. This method improves the efficiency of vehicle localization and realizes vehicle localization with high precision.

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    High Precision Distance Measurement Based on Monocular Vision for Intelligent Traffic
    ZOU Bin, YUAN Yu-xiang
    2018, 18(4): 46-53. 
    Abstract ( )   PDF (4918KB) ( )  

    The preceding vehicle distance is a significant factor, affecting driving safety. A preceding vehicle distance measurement based on monocular vision for future intelligent traffic system is proposed. First, the model of internet of vehicles is proposed with the fusion of internet of things, intelligent recognition, and cloud computing technology. The vehicle can send back the location information and the preceding vehicle image to the internet of vehicles in real time, and request the nearby traffic signs and the geometry of the preceding vehicle. Then, establish a mathematical model of the monocular camera, and introduce a distance measurement based on monocular vision with a cooperation sign of traffic signs and lane lines. Finally, a preceding vehicle adaptive vision distance measurement is designed by comprehensive application of the distance measurement based on monocular vision. The simulation demonstrates that the distance measurement based on monocular vision is valid and effective, enriching driving assistance system.

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    Dynamic Group Generation for Airport Ground Staff Scheduling
    LU Min, WANG Li
    2018, 18(4): 54-60. 
    Abstract ( )   PDF (3580KB) ( )  

    The problem of scheduling airport ground staffs is to dynamically generate groups and assign employees to groups. The existing group-specific staff scheduling algorithms are built on the fixed number of groups. Nevertheless, it is impractical to know the number of groups in advance. An algorithm is proposed to address the issue via dynamically generating groups. Its key idea is to employ Gibbs sampling with replacement to iteratively optimize three sub-problems: assigning staffs to groups, allocating flights to groups and group generation. Experimental results on a real dataset demonstrate that the proposed algorithm can generate reasonable groups under the constraints of skill requirements for flights and shifts for employees.

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    Bus Speed Control Strategy and Algorithm Based on Real-time Information
    YAN Hai, LIU Run-kun
    2018, 18(4): 61-68. 
    Abstract ( )   PDF (5250KB) ( )  

    According to the unstable phenomenon of bus arrival time, a real-time bus speed control strategy is proposed in this paper, aiming at minimizing the mean absolute error of bus headway. Three kinds of bus operation scenes are designed, and the expected speed is calculated based on the real time traffic state and the passenger arrival rate. Through numerical simulation, the stability of the bus headway, the reliability of the bus running time, the average waiting time of the passengers and the speed of the operation are evaluated. The results show that the strategy can improve bus headway stability about 77.63% and bus operation reliability about 93.5%, which is the best in the three scenarios. However, the average waiting time for passengers will increase about 6.12% when the impact of road traffic flow is considered. Therefore, the strategy is more effective for improving stability of the route which is less affected by the traffic flow or shorter in length. To achieve the goal of improving stability, the target bus is not necessary to travel as fast as possible.

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    Multi-approach Collaborative Release Method of the Signalized Four-leg Roundabout
    MA Xin-lu, YANG Xing-qing
    2018, 18(4): 69-75. 
    Abstract ( )   PDF (4461KB) ( )  

    For the problem of intersection delay caused by mutual interference between circulating vehicles of the signalized four-leg roundabout, the paper proposes a signal control method for multi- approach collaborative release. Firstly, a dynamic model is established based on a cell transmission model, which uses to describe traffic flow characteristics of the signalized four-leg roundabout. Then, a signal optimization model is established with intersection delay as the optimization goal and timing parameters as target variables, and the signal timing parameters are obtained through optimization with the genetic algorithm. Finally, the applicability of the model is analyzed by cases. The results show that vehicle delay of circulating lane was improved obviously after channelization of the left-turn and straight lane of the four-leg roundabout. Compared with the single-approachentering operation, the proposed multi-approach collaborative release control method can effectively relieve the vehicle delay of intersections.

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    Release Characteristics and Safety Evaluation of Intersection with Reversing Variable Lane
    QU Zhao-wei, QI Xing-zu, CHEN Yong-heng, TAO Chu-qing, BAI Qiao-wen, LIU Fang-hong
    2018, 18(4): 76-82. 
    Abstract ( )   PDF (5474KB) ( )  

    The statistical analysis is used to compare the safety risk between the intersection of the reverse variable lane and the conventional intersection. The results show that the ratio of pre-signal red light crossing at the intersection with reverse variable lane is significantly increased. The average speed of driving in the lane is reduced by 15.31% . And also the feature of release and the spatial trajectory of the intersection with reverse variable lane are analyzed through probability statistics and video processing technology. Conflicts between the traffic flow of reverse variable lane and traffic flow of left lane are determined by using the traffic conflict technique (post encroachment time) and the test is carried out with the dual left-turn lanes to find out that setting reverse variable lane increase the level of interference between the intersection of left-turn traffic flow. The results of this study may help to provide a theoretical basis for the setting of reverse variable lane and improve the safety of the intersection with the reverse variable lane.

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    A Support Vector Machine Approach on Real-time Hazardous Traffic State Detection
    YOU Jin-ming, FANG Shou-en, TANG Tang, ZHANG Lan-fang
    2018, 18(4): 83-87. 
    Abstract ( )   PDF (3046KB) ( )  

    The real-time detection of traffic flow safety is the prerequisite for active traffic safety management. The paper sets the traffic states prior to the crashes as the criterion of hazardous traffic states. Parameters are extracted based on the lane-level traffic data and 9 parameters are selected with the principle component analysis. A support vector machine approach with radial basis kernel function is utilized to detect the real-time safety of the traffic flow. Grid search method is employed to select the optimized penalty parameter C and the kernel function parameter γ. Results indicate that the support vectors machine classifier could successfully classify 79.55% of the hazardous traffic states prior to the crashes. The method could be utilized to detect the hazardous traffic states on freeway in real time efficiently.

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    Anchors Identification in Trajectory Based on Temporospatial Clustering Algorithm
    ZHOU Yang, YANG Chao
    2018, 18(4): 88-95. 
    Abstract ( )   PDF (4770KB) ( )  

    Based on the individual GPS data collected by the mobile terminal like smartphones, a novel spatiotemporal clustering algorithm called AT-DBSCAN is proposed to identify anchors in the trajectories. In this algorithm, the core points are found and checked within a sliding window, the similarity is defined by the temporospatial difference, and clusters are merged according to the density. Rather than using the recall or precision to evaluate results, the consistency of travel times, the comprehensive bias when the travel starts and ends, the difference between anchors duration, and the central distance between the true and identified anchors, are proposed and applied to get the exact temporal-spatial information. Results suggest that 98 percent anchors’ distances are less than 30 meters, 100 percent duration difference are less than 5 minutes, and 98 percent travel time difference are within 5 minutes. Besides, the proposed algorithm also has a good performance in generalization of indoor activity, positioning drift and severe overlying segments.

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    A Class of New Lattice Model with Consideration of the Optimal Current Changes with Memory
    ZHAI Cong, LIU Wei-ming, HUANG Ling
    2018, 18(4): 96-102. 
    Abstract ( )   PDF (3870KB) ( )  

    Based on the effect of optimal current estimated by the driver, meanwhile, the driver is affected by the memory time during driving, in this paper, a new lattice model is presented with the consideration of the optimal current change with memory effect. The model’s linear stability condition is obtained by applying the linear stability theory, and through nonlinear analysis, a modified Korteweg-de Vries (mKdV) equation is derived to describe the propagating behavior of traffic density wave near the critical point. Numerical simulation verified that not only the sensitivity of the optimal velocity change with memory of driver but also the memory step could effectively stabilize the traffic flow. In addition, the stability of traffic flow is strengthened by increasing the memory step-size of optimal current changes and the intensity of drivers’ memory with such changes that the new model can improve the stability of traffic flow by adjusting the driver’s memory parameter, which is consistent with the theoretical analysis.

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    Systems Engineering Theory and Methods
    Integrated Bus Control Strategy Considering Holding and Limited-boarding
    HUANG Qing-xia, JIA Bin, QIANG Sheng-jie, XIAO Yao
    2018, 18(4): 103-109. 
    Abstract ( )   PDF (3709KB) ( )  

    To reduce bus bunching and improve service reliability, this paper proposes a headway-based threshold integrated bus control strategy, which combines holding with limited boarding. To evaluate the strategy in a systematic manner, a simulation framework based on cellular automata has been developed to depict the operations of buses and the activities of passengers, and the parameters involved are calibrated by data from a real-life bus route. In the simulations, we analyze the influences of control parameters on different performance measures. The results show that, when minimizing passenger average waiting time, the obtained integrated strategy has a greater ability to improve service reliability; while it performs higher passenger travel efficiency and bus operating speed, when minimizing passenger average travel time.

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    Emergency Bus Reserve Location Based on Risk Analysis of Passengers Stranded at Urban Rail Transit Station
    LIU Shuang, ZHI Xiao-yu, CHEN Shao-kuan, XING Yan
    2018, 18(4): 110-115. 
    Abstract ( )   PDF (3393KB) ( )  

    Along with the urban rail transit network expansion and rapid growth in passenger flow, the risk of passengers stranded at the station and emergency response problem are getting more attention. This paper sets up arisk evaluation index system and back-propagation neural network (BPNN) based on an analysis of passenger stranded risk, and combining the improved P-center location model, a service matching scheme for the URT stations and emergency bus reserve bases is proposed. The case solution and program comparison show that the risk weight has an influence on the relative importance among stations during location process, which decreases the average distance between high-risk stations and the EBRB by 0.8%~8.4%, but has little impact on the service coverage effect of the whole study area, so it's beneficial to the reasonable and efficient utilization of emergency resources.

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    A Regret-based Stochastic User Equilibrium Model Considering Travelers’Loss Aversion
    ZHAO Lei, GUAN Hong-zhi, ZHANG Xin-jie, ZHAO Peng-fei
    2018, 18(4): 116-122. 
    Abstract ( )   PDF (3820KB) ( )  

    Based on the classical random regret minimization model, this paper develops a new attribute level regret function by introducing travelers’ loss aversion and proposes Logit-based stochastic user equilibrium model. In the proposed regret function, the difference between the regret generated by a loss and the rejoice generated by a gain with equal size is jointly affected by the taste parameter reflecting the relative importance of the regret and rejoice and loss aversion of travelers. In addition, the equivalent variational inequality problem of the proposed stochastic user equilibrium is given and the method of successive average is applied to solve it. Finally, a simple example network is used to prove the reasonability of the model and the feasibility of the algorithm. The results show that travelers’ loss aversion has a great impact on route choice behavior. Moreover, travelers will be more inclined to choose the shortest route as the degree of the loss aversion increases.

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    A User Equilibrium Model Considering a Degradable Transportation Network and Double Reference Points
    WEI Qing-qi, XIAO Wei
    2018, 18(4): 123-129. 
    Abstract ( )   PDF (3880KB) ( )  

    Considering a degradable transportation network and double reference points, a user equilibrium model is developed in this paper. Then we examine the existence of the equilibrium solution, and design a solving algorithm. This model is suitable to find out the relationships among capacity degradation, travel time expectation and variance, best arrival reference point, earliest arrival reference point, cumulative perceived value, and equilibrium network flow. Finally, a numerical example is conducted to analyze the effect of capacity degradation on traveler and traffic equilibrium.

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    Preference Reversals Phenomenon of Travel Mode under the Equate-to-differentiate Interpretation
    ZHANG Nian, LUO Xia, DENG Yan
    2018, 18(4): 130-134. 
    Abstract ( )   PDF (2908KB) ( )  

    In the travel investigation for school bus and 119 road bus between the two campus of Southwest Jiaotong University,we found the inconformity between the preferences and evaluation for these two travel mode. Through experimental design of cautious control, the existence of preference reversal phenomenon is confirmed. Under the equate-to-differentiate interpretation, we establish the judgment dimension system of option attributes, and carry out the psychological experiment of matching task. Test results show that,there is significant relationship between the matching task and preference, and PRP can be explained under the equate-to-differentiate interpretation. Then we change the order of experimental task, proving the preference could be forecasted under the equate-to-differentiate interpretation, and preference is the process of equate-to-differentiate, but not dimension integration. At last, we carry out two groups of experiments under the risk condition, and the results show that probability does not necessarily improve the level of decision-making, and the phenomenon of preference reversal is not due to the fact that preference really reverses, but the different strategic process, and the different judgment results of dimension cause the preference reversals.

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    Urban Freight Vehicle Type Choice Model and Application
    ZHANG Rong, LI Lu, JIAN Wen-liang
    2018, 18(4): 135-141. 
    Abstract ( )   PDF (3969KB) ( )  

    This paper takes the urban freight vehicles travelling in the center of Shanghai during the daytime as objectives. Multinomial Logit Model and Nested Logit Model are established considering vehicle type, tour and company related attributes. The results show that the travel cost, travel time, loading rates, the number of stops and the satisfaction degree of traffic permits are all significant. Then the Nested Logit Model is chosen to evaluate freight passing policies. The results show that the adjusted freight passing policies can transfer the share rate of the seven-seat car to the small freight vehicle effectively. Besides, the share rate of the seven-seat car has significant variation among tours with different stop numbers. At last, suggestions are provided to improve the phenomenon of delivering goods by passenger cars.

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    Complex System of the Risk on Dangerous Goods Transportation & Risk Assessment Model and Application:Take Liquid Chlorine as an Example
    WANG Hai-xing, LIANG Qian-qian
    2018, 18(4): 142-147. 
    Abstract ( )   PDF (3826KB) ( )  

    The risk system analysis and risk measurement of dangerous goods road transportation based on the overall optimal system are the key technologies to avoid the high risk section. This paper, taking the risk of dangerous goods as the research object, combines the typical regional characteristics, carries on the system analysis of the dangerous goods road transportation risk and puts forward the concept complex system of the risk on dangerous goods transportation. Based on this, the paper puts forward the risk measurement model of road transport of dangerous goods, and takes the application of liquid chlorine road transportation of typical dangerous goods as an example. In the study of risk measurement model of road transport of dangerous goods, two indicators of exposure population risk loss and environment-sensitive area loss caused by leakage accident are taken as object of evaluation, combined with ALOHA to simulate the situation of leakage accident and the diffusion into ArcMap to analyze the loss caused by leakage accident. Considering transportation cost, a dual objective programming model for road transportation of dangerous goods with the best overall system, the minimum risk and the lowest transportation cost, is established. Finally, an example is used to verify the practicability and validity of the model by using the ant colony algorithm.

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    The Impact of Window Size and Sliding Length on the Results of Black Spots Identification
    MENG Xiang-hai, ZHANG Dao-yu, WU Pei-jie
    2018, 18(4): 148-155. 
    Abstract ( )   PDF (4788KB) ( )  

    Taking Jingzhu freeway for example to identify the black spots, analyzing the potential issue of sliding window application, and discussing the impact of window size and sliding length on the results of black spots identification. Finally, a method is provided based on Quantile Method to choose the optimum window size and sliding length. The result shows that different size of window and sliding length decide the different result of black spots, if the window size and the sliding length is unseasonable or the method are used incorrectly, the results will be omitted or be exaggerated when use the sliding window identify the black spots. The longer the window size, the longer black spots be identified. The longer the sliding length, the less black spots be identified. It is optimum combination that the ratio of the sliding length to the window size is 0.4 ~ 0.8.

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    An Ant Colony Optimization for the Bi-objective Vehicle Routing Problem with Time Windows on Mutilgraph
    CHAI Huo, HE Rui-chun, SU Jiang-sheng, SONG Yu-bo, DAI Cun-jie, MA Chang-xi
    2018, 18(4): 156-162. 
    Abstract ( )   PDF (4179KB) ( )  

    An ant colony algorithm is designed for the vehicle routing problem with time windows on multigraph. A mathematical bi-objectives optimization model of vehicle routing problem with time windows on multigraph is established firstly, and a search space construction method for the solution of the problem is proposed. Then, a state transition probability formula that combines the heuristic information about optimization objectives, time windows, pheromones is defined. In order to illustrate the effectiveness of the algorithm by comparison, a multi-objective genetic algorithm based on NSGA-II is designed at the same time. In the example, the sensitivity of each parameter in the ant colony algorithm is analyzed. According to the analysis results, the algorithm parameters are set up, and the Pareto-optimal path set of the example is obtained. The CPU time, convergence and population diversity are compared with the NSGA-II algorithm and existing ant colony algorithm. The comparison results show that the three indexes of the ant colony algorithm designed are more competitive than the NSGA-II algorithm, and convergence and population diversity are better than existing ant colony algorithm.

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    A High-speed Railway New-added Train Timetable Partial Adjustment Model Based on Lagrangian Relaxation
    JIANG Feng, NI Shao-quan, LV Hong-xia
    2018, 18(4): 163-170. 
    Abstract ( )   PDF (4078KB) ( )  

    Give ideal departure time and initial profit for each new train path, consider the penalties caused by departure time adjustment and total stop time prolong, based on a time-space graph build an ILP model which take the maximum total profit of the timetable as object function, relax the model in a Lagrangian way, take consideration of the relaxation dual information to design a heuristic algorithm to get the practical solution of each train path, optimize the global solution by updating the Lagrangian multipliers. JingHu high-speed railway was taken as a verification case, the results show: under the given case, compared with the existing timetabling method that search the train path according to the departure time instant, the proposed method scheduled 6 more train paths; with the departure time window expanded from 10 min to 60 min, the solving time of CPLEX increased dramatically, while Lagrangian method had a shorter solving time and could get better solutions than CPLEX except the 10 min scenario. Prolong the departure time window to 4 h, at most 18 new trains are scheduled, which proved that the capacity of JingHu high-speed railway is nearly saturated under the case-study situation.

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    Optimal Maintenance Planning Model for Railway Rail Grids
    BAI Lei, JIA Chuan-jun, LI Qing, LIU Reng-kui, SUN Quan-xin
    2018, 18(4): 171-177. 
    Abstract ( )   PDF (4329KB) ( )  

    Optimal maintenance planning is of great significance for managers to allocate resource properly and ensure the railway traffic safety. Using the grid-based management theory for railway infrastructure, a railway line is divided into adjacent segments of the same specific length. Each segment is termed a “rail grid”. Rail grids are the subjects of this paper. Employing the multi-stage exponential Markov model, the degradation law of each rail grid is obtained. Markov decision process is employed to establish a condition-based maintenance policy model, and find optimal maintenance policies over a finite planning horizon. The objective is to minimize the total expected cost. Actual data for the Longhai Railway is used to verify the proposed model. The proposed model is superior to the threshold-based China Railway's existing management methods.

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    Joint Optimization of Loading Sequence and Yard Crane Travel Route in Container Terminals
    GUO Wen-wen, JI Ming-jun, ZHU Hui-ling, WANG Qing-bin
    2018, 18(4): 178-187. 
    Abstract ( )   PDF (4876KB) ( )  

    To reduce the number of rehandles and the operation time of yard cranes, considering the known ship stowage plan and yard stacking status, this paper studies the joint optimization problem of loading sequence and crane travel route. The integer programming model is established to minimize the operation time, which measures the number of rehandles and the crane travel route by operation time. The heuristic algorithm considering the rehandles and yard crane operation time is designed to solve the problem. The lower bound is proposed to verify the effectiveness of algorithm. Meanwhile, numerical examples are designed to compare the heuristic algorithm and lower bound, which provides the decision making for terminal operator.

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    Passenger Choice Behavior Model and Empirical Study under Flight Delay Information
    JIANG Hong, REN Xin-hui
    2018, 18(4): 188-193. 
    Abstract ( )   PDF (3231KB) ( )  

    In view of the uncertainty of passengers' choice behavior after flight delay, this paper studies the choice behavior of passengers under different delay situation based on cumulative prospect theory. First of all, the passenger choice behavior model under flight delay information is proposed by taking the expected travel time as reference point. And the reference point is dynamic in different delay situation. The time sensitivity, degree of information impact and the judgment of travel time in different delay situation are obtained by questionnaire. According to these parameters the paper calculates the expected travel time. Finally, taking Beijing-Shanghai route as an example, the cumulative prospect values of passengers' different behaviors under different delay situation are calculated, thus obtaining the optimal choice behavior of passengers. The results show that, with the increase of flight delay scale and delay time, the expected travel time of passengers will grow, reflecting the dynamic characteristics of the reference point. Under different delay situations, the optimal choice behavior of passengers is different. Verified by practice, the theoretical model can effectively describe the choice behavior of passengers at different delay situation.

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    Flight Operations Risk Improvement Prediction Based on Adaptive Lasso and RF
    WANG Yan-tao, CHEN Guan-ming, LIU Yu, YANG Yuan-hao, ZHAO Hang
    2018, 18(4): 194-201. 
    Abstract ( )   PDF (4327KB) ( )  

    In order to solve the problem of high computation complexity of flight operations high-dimensional arrays, and to avoid models over-fitting and the prediction precision influence, the 450 real flights data of certain airlines and the risk assessment system issued by the Civil Aviation Administration of China are used. Firstly, Adaptive Lasso is used to reduce dimensions, the fifteen independent variables are selected from 63 risk factors. Then, 12 items with the highest importance ranking and lowest error are retained according to the random forest over-fitting test results. Finally, the two methods are combined as a two-step hybrid algorithm; the principal component analysis, RBF neural network and support vector machine are selected for comparison and analysis; 10-fold cross validation is used to confirm outcome. The results show that the results accuracy does not change significantly after 48 indicators deleted by Adaptive Lasso method,and the assessment accuracy after RF processing is better than before RF. The prediction accuracy and stability of the Adaptive Lasso-RF hybrid model are better than that of principal component analysis, RBF neural network and support vector machine. All above conclusions indicate the Adaptive Lasso-RF prediction method is feasible and effective to solve the flight risk prediction problem, which can reduce dimensions, avoid models over-fitting and improve accuracy significantly.

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    An Improved Spatial Vulnerability Model for Civil Aviation Network
    LI Hang, HU Xiao-bing
    2018, 18(4): 202-208. 
    Abstract ( )   PDF (3745KB) ( )  

    Vulnerability is an important concept to reflect the performance of a system at face of a hazard. In order to show the vulnerability of civil aviation network systems under hazards as realistic as possible, we must consider the hazard spreading effect, i.e., hazard indirect impact in civil aviation networks reasonably and adequately. Based on recent studies on spatial vulnerability model, we analyze the characteristics of hazard spreading effect in civil aviation network detailedly, determine three key factors for calculating hazard indirect impact, including link between airport flights, distance between airports and failure threshold of airports, and specific method, then propose an improved spatial vulnerability model for civil aviation network. Finally, a case study on Chinese civil aviation network system is conducted to verify the effectiveness of the improved spatial vulnerability model.

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    Cases Analysis
    Energy-saving Effect Analysis of Policies Based on Passenger Cars Fuel Accounting Model
    LIU Yu-huan, YAO En-jian, GU Yan, LI Meng
    2018, 18(4): 209-214. 
    Abstract ( )   PDF (3486KB) ( )  

    In recent years, the problem of energy consumption and emission pollution caused by fast growing private cars is becoming more and more serious. How to build a fuel accounting model for private passenger cars and analyzing the macro energy saving effect of different TDM (Traffic Demand Management) policies are essential to urban traffic related energy saving and emission reduction. Considering the problem that the accuracy of energy consumption data derived from conventional survey for private passenger cars is poor and unable to meet the delicacy management requirements of urban traffic energy conservation and emission reduction. In this study, using the existing survey data and monitoring data and based on the method of “OLS( Ordinary Least Square) + Robust standard deviation”, the significant influencing factors are analyzed,and an accounting model of energy consumption for private passenger car based on traffic big data and applies it to the macro analysis of energy saving effect of TDM policy is proposed. The reliability and effectiveness of the proposed model are then verified by using the measured data of Beijing. Finally, the macro effect of private car's energy saving under different TDM policies (including combined policies) are analyzed. The result shows that when the policy effect indicators change at the same rate, the total fuel consumption reduction resulted from the policy combination of congestion charging and controlling the number of large-displacement passenger cars is largest.

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    Systems Engineering Theory and Methods
    Taxi Demand Prediction Based on CNN-LSTM-ResNet Hybrid Depth Learning Model
    DUAN Zong-tao, ZHANG Kai, YANG Yun, NI Yuan-yuan, SAURAB Bajgain
    2018, 18(4): 215-223. 
    Abstract ( )   PDF (5094KB) ( )  

    To forecast the demand of the taxi, it is significant part of smart city and intelligent traffic system to use large amount of off-line GPS data. A deep learning-based, CNN-LSTM-ResNet, is proposed for the demand of taxi in this paper. We converted GPS data of taxi and weather data into raster data, and put them into the model as input to obtain the predictions. Firstly, Convolutional Neural Network (CNN) is used to extract the spatial features of urban traffic flow, and Residual Units to deepen the layers of network, then to extract the temporal proximity, periodicity and tendency of the GPS data, Long Short-Term Memory (LSTM) is used. Finally, to predict the demand of taxi in specific areas of the city, three components are fused by the corresponding weights, and the syncretic result is combined with external factors, like the weather, holiday and air quality index. The experiments are conducted on taxi GPS data of Xi’an, and the result shows that prediction accuracy of proposed model is much more higher than the traditional models such as ARIMA, CNN and LSTM.

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    Cases Analysis
    Metro Station Classification by Service Function Based on AFC Data and RF Method
    WANG Zi-jia, LIU Hai-xu, TAKU Fujiyama
    2018, 18(4): 224-230. 
    Abstract ( )   PDF (4302KB) ( )  

    The spatial distribution of the type of passengers rail stations serving is an indicator of urban structure. This paper analyzes the spatial and temporal evolution of the type of passenger flow on the whole network station service by using random forest model (RF) and automatic fare collection (AFC) data. For the traditional RF model relying too much on subjective experience in selecting training sets, this paper firstly uses traditional RF model to measure the degree of similarity between stations, and then adopts the PAM method to cluster. Clustering results show that the unsupervised RF method has better accuracy. Finally, based on a large amount of AFC data and unsupervised RF method, we reveal the change of metro station attribute from 2014 to 2017 in Beijing. The analysis shows that the city’s structure of job and house location in Beijing has largely remained unchanged on a large spatial scale in the past four years, but the functional areas within the city are undergoing a slow variation, and the area where stations serving both commuting and living passengers are hot spots in the evolution of urban structure. The research results of this paper can provide a new perspective for the understanding of the interaction between urban rail transit and urban structure.

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    Customer Segmentation for Expressway ETC System
    QIAN Chao, YANG Meng, GENG Jian, XU Hong-ke
    2018, 18(4): 231-239. 
    Abstract ( )   PDF (4676KB) ( )  

    Applying big data technology, a customer segmentation method of electronic toll collection (ETC) system is presented based on vehicle behavioral characteristics. A segmentation index system of ETC customer consisting of Recency, Frequency, and Monetary is constructed and extracted using ETC data. The whole sample clustering analysis of ETC customer is accomplished by CLARA algorithm while overcoming the invalidation problem on big data clustering. The decision tree of ETC customer segmentation is finally built and transformed into a set of segmentation rules. The empirical results indicate that the proposed method has a better ability to analyze the traveling characteristics, present values and appreciation potentials for different classifications of ETC customers. It provides an innovative idea to implement precision marketing and make hierarchical discount rates for ETC customers. Meanwhile, it provides theoretical support to further increase of ETC customer scale and paying ratio, as improve decision-making level in expressway operation and management.

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    A Real-time Identification Method of Highway Service Level Based on Multi-dimension Data
    ZHAO Wen-zhong, GENG Li-yan, LIANG Yi-gang, ZHANG Zhan-fu
    2018, 18(4): 240-246. 
    Abstract ( )   PDF (4024KB) ( )  

    With the continuous development of highway, traffic information of highway is diversified gradually. Integration of the traffic of highway and real-time identification of the service level of highway is very important for the later traffic controlling and management and provision of real-time and efficient road information. Combing least squares support vector machine with cluster analysis algorithm, this paper proposes a real-time identification model of highway service level based on multi-dimension data in order to achieve the parameter prediction and real-time identification of highway service level. The model includes many influence factors, such as time, weather, travel dates and so on. In addition, it selects vehicle speed and density to evaluate highway service level. The validity of the model is tested by using 237 360 training samples and 6 048 prediction samples of Hebei province. The results show that the model produces the higher identification accuracy and better prediction effect, which is a method for real-time identification of highway service level.

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