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Articles

by Yong-Chun He
31 Views, 0 PDF Downloads

Co-delivery can effectively improve the utilization of logistics resources and reduce logistics costs. Under this environment, this paper proposes a vehicle routing problem with order selection. Transportation companies can entrust transportation orders to cooperative enterprises or accept orders issued by cooperative enterprises. At the same time, order selection and vehicle path optimization are needed. In order to optimize the economic benefits of the enterprise, a mixed integer programming model is established. A genetic algorithm is designed to solve this NP-Hard problem, and the chromosome coding of the problem is proposed. An accurate segmentation algorithm to obtain the structure of feasible solutions. This paper constructs examples of different scales and uses Matlab to carry out numerical experiments. The results show that the transportation enterprises can effectively reduce the driving distance of vehicles and improve the enterprise through the two-way entrustment of orders. The economic benefits provide a theoretical basis for the analysis of individual behavior in the common distribution system.

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Articles

by Weiyi Zhu
40 Views, 0 PDF Downloads

Taking Kunming subway first phase project ring--Kunming section overlapping tunnel as the project background, using MIDAS/ GTS and finite element program to simulate shield excavation process, using first-down and then-up excavation methods and different overlapping angles as construction conditions, analyzing the influence of overlapping tunnel construction on surface settlement and segment internal force under different overlapping angle conditions. The results show that, the surface settlement and segment internal force change with the change of overlapping angle, overlapping angle decreases, surface settlement range increases, while the maximum settlement value and segment stress both decrease. 

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Articles

by Xiang-Ming Liu
41 Views, 0 PDF Downloads

Train Passenger Information Display System (PIDS) is one of the vehicle systems that directly contact passengers. Its Performance Reflects the Level of Train Operation Service. Passenger Information Display System including 3 subsystems: Broadcasting System, Video Monitoring System and Media Display System. This article only discusses the broadcasting system. First,the function of broadcasting system is introduced. Second, explain the control logic of automatic station reporting of the broadcasting system, and put forward optimization suggestions for problems occurring in the subway operation process. Finally, compare and analyze 2 kinds of automatic station reporting modes.

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Articles

by Maocai Du
53 Views, 0 PDF Downloads

Analyzed the Time Series Characteristics of Ship AIS Data and Ship Handling Characteristics, Proposed Improved Sliding, Window and Online Compression Algorithm; Calculated 277 Total Ships 1 026 408 Coordinate Points, AIS and Track Data, Determined the appropriate compression threshold, Analyzed the sensitivity of distance threshold and angle threshold to the compression ratio of the algorithm; Recommended the distance threshold of high, medium, low 3 and 1 angle threshold, Contrast Douglas-Peucker Algorithm and Improvement Sliding Window Algorithm Compression Ratio and Compression Efficiency. Test results show that: as the compression rate increases, the number of points left after compression, the useful information retained by the data is also less and less; the compression rate is proportional to the distance threshold, the angle threshold; the high, medium, the low-range compression distance threshold after dimensional 1 normalization They are 43%, 38%, 33% Captain; Distance Threshold 130m Time, Angle Threshold Exceeds 9° Stable Post Compression Rate, So Recommended Angle Threshold is 9°, and Harbour Master Design Code (JTS XZ8 024--2013) Stroke Flow Pressure Difference Angle 8° Close; With Increase of Distance Threshold, Douglas-Peucker Algorithm and Improvement Sliding Window Algorithm Compression Rate Closer, When Distance Threshold is 120m, Douglas-peucker algorithm compression ratio is only higher than improved sliding window algorithm 1.74%; Under 5 Different Distance Thresholds, Douglas-Peucker The average time taken for the algorithm to run is improved Sliding, Window and 5 of the algorithm. 39 Times; With the Increase of Data Quantity, 2 The Difference in Compression Efficiency of Different Algorithms Is More Obvious. Visible, Improved Sliding Window algorithm can greatly improve compression efficiency while reducing compression risk, Can keep compression state in the state of continuous data update, Compared with normal compression mode, System occupies less resources, Processing efficiency is higher, Can be used for ship trajectory data processing, Electronic chart display and extraction of key behavior characteristics of ships.

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Articles

by Hao Lee
47 Views, 0 PDF Downloads

By mining massive AIS data, a new method for obtaining channel water depth information is proposed, that is, to construct a reference for safe navigation of ships; to clean and repair historical and online AIS data by data preprocessing method, to generate ship motion trajectory; to select the time, longitude and latitude of ship navigation area, to use K-means clustering algorithm. Cluster analysis of draft data during ship navigation is carried out to obtain ship classification in different safe navigation areas. BP neural network model is used to predict and fill the maximum draft information missing from AIS data. Historic ship trajectories are segmented and Spline interpolation method is used when the time interval of sub-trajectories is 10-20 minutes. The lost data are interpolated; the safe navigation depth area maps of the same kind of ships are constructed by convex hull, and the safe navigation depth area maps of different draft types are merged to obtain the merged safe navigation depth maps of ships; the merged safe navigation depth maps of different draft types are superimposed with the channel maps to obtain the reference of safe navigation depth of ships. The experimental results show that when the parameters of the clustering algorithm are set to 4, four types of ships can be obtained after clustering. The corresponding maximum draught ranges are 0.1-4.8, 4.8-6.6, 6.6-10.0, 10.0-13.0 m, and the corresponding draught of at least navigable ships are 1.8, 2.4, 3.3 and 5.0 m, respectively. The maximum draft is positively correlated with the draft of at least navigable ships; the reference of safe navigation depth of ships constructed covers 86% of the channels in the electronic channel chart and coincides with the Deep water part of the channel chart at 80%. Therefore, the reference of safe navigation depth of ships constructed can reflect the real situation of the channel depth and meet the navigation needs of different types of ships.

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