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Xian, China

Long J.,Central South University | Huang G.,Xian Railway Bureau | Wang M.-J.,Central South University | Zhang Y.-C.,Central South University
Jiaotong Yunshu Gongcheng Xuebao/Journal of Traffic and Transportation Engineering

In order to solve the reserve depot location problem of railway emergency material with the restrictions of response time and minimum number of reserve depots, complex railway network was simplified to sections by analyzing the uniqueness of the problem. A mathematic model was established relying on supply and demand matrix, and its solving program with improved branch and cut search method was introduced. The reserve depot location problem of a railway bureau was taken as an empirical analysis. Analysis result indicates that choosing Yanliang as reserve depot is correspond to reality, the model simplifies complex railway network to sections with the premise of ensuring the consistency of effective solution, and eliminates the constraint of point covering line, so the model is more applicable to the reserve depot location problem of railway emergency material. Source

Du J.,Changan University | Du J.,Shaanxi Road Traffic Detection and Equipment Engineering Research Center | Hao J.,Xian Railway Bureau | Fan H.-W.,Changan University
Jiaotong Yunshu Xitong Gongcheng Yu Xinxi/Journal of Transportation Systems Engineering and Information Technology

The expressway toll data are high-dimensional and massive, of which distribution is unknown, therefore it is hard to decide which algorithm and what parameters are more suitable for clustering to this kind of data set. Aiming to this problem, IBCS, a clustering evaluation index based on balance of clusters' shapes, is proposed, and various cluster shape features which include outline, distribution, density, and sizes, are evaluated evenly and synthetically. By means of this index, the neighborhood confidence interval is adjusted adaptively according to data set sparsity, and the degrees of scattering and separating to cluster structure are measured. With density evaluation, IBCS is provided with capability of selecting algorithm for data set. With size evaluation, the problem that clusters are too different after separated is avoided. Results of comparison experiment on UCI data set with several candidate algorithms show that, IBCS is feasible and efficient, and the correct cluster number and clustering pattern are achieved. Finally, result of Xi'an-Baoji expressway toll data clustering based on IBCS indicates that, the clustering scheme with K-means algorithm and 5 clusters is optimal. Copyright © 2016 by Science Press. Source

Peng H.,Changan University | Zhao J.-F.,Xian Railway Bureau | Wang A.-Y.,Changan University | Chen G.-D.,Changan University
Jiaotong Yunshu Xitong Gongcheng Yu Xinxi/Journal of Transportation Systems Engineering and Information Technology

Entrusted transportation management model is an important form of joint-venture railway in China. To establish a macro, reasonable and effective management mechanism of entrusted transportation management model for joint-venture railway, the principal-agent theory is used on the bases of Douglas function. The optimal incentive-compatible mechanism is constructed on the case of symmetric and asymmetric information. On the basis of survey data of Xi'an Railway Bureau and Xiyan Joint-venture Railway Company. It analyzes the model and obtains that the coefficient of excitation intensity is 7.2%, and also demonstrates operation management mechanism and incentive-compatible policy on the basis of entrusted transportation model of joint-venture railway. Finally, from Railway Bureau and joint railway company, it puts forward the strategies to construct incentive-compatible mechanism of joint-venture railway by analyzing the potential problems of incentive-compatible mechanism, and provides the theoretical analysis method for the joint-venture railway of entrusted transportation management model. Source

Yan R.,The Experimental Center for Minig and Metallurgy and Environmental Science of Guangxi | Yan R.,CAS Wuhan Institute of Rock and Soil Mechanics | Wei C.,CAS Wuhan Institute of Rock and Soil Mechanics | Fu X.,The Experimental Center for Minig and Metallurgy and Environmental Science of Guangxi | And 2 more authors.
Yanshilixue Yu Gongcheng Xuebao/Chinese Journal of Rock Mechanics and Engineering

Based on the two synthesis methods of hydrate in soils, the unsaturation sampling(US method) and gas diffusion sampling method for saturation soil(SD method), triaxial shear tests are performed to study the effects of occurrence mode of hydrate on the mechanical properties of hydrate-bearing soils containing CO2. The experimental results confirm that the occurrence mode and saturation of hydrate have significant impact on the mechanical behaviour of soil with hydrate. In view of the microscopic mechanism, some analysis indicate that samples formed by US method, which are called as cementation mode, exhibit some structure characteristics of cementing soil. the samples formed by SD method, which are called as pore filling mode, loading mode and lenticle mode, show the properties of the friction material significantly, and exhibit strain softening due to the crushing damage of hydrate during the shearing period. Besides, by introducing a new parameter-the effective saturation of hydrate, a formula considering the influence of hydrate synthesis methods, which can predict the shearing strength of hydate-bearing soil, is proposed. Source

Zhang Y.,Xian Railway Bureau | Zhang Y.,Lanzhou Jiaotong University
Zhendong yu Chongji/Journal of Vibration and Shock

Dynamic behavior of a electrodynamic tethered system operating in a circular inclined orbit was studied. The dynamic model of the system was described, the basic periodic solution was obtained using perturbation method and a new numerical method. The stability of the periodic solution was analyzed based on the stability criterion in the numerical algorithm and it was concluded that the system periodic motion is instable. Finally, two algorithms were compared with simulation. The results showed that the periodic solutions obtained with the two algorithms are the same basically when perturbation is smaller, but the periodic solutions obtained with perturbation method are distorted when perturbation is large, at this time the numerical algorithm is normally adopted; instability of the periodic solutions is also confirmed with the simulation results. Source

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