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Bai L.,China Academy of Railway Sciences
Jiaotong Yunshu Xitong Gongcheng Yu Xinxi/Journal of Transportation Systems Engineering and Information Technology | Year: 2017

Urban rail transit passenger flow characteristics show not only the periodicity, seasonal and normality peak, but also the difference and particularity because of holidays, sports events, urban large-scale events, emergencies, special weather and other factors. In this paper, we carry out the method and realization of more mature normal and poorly studied abnormal passenger flow prediction. Firstly, the general ARIMA time series prediction algorithm is used to analyze the sample history data to realize the normal daily passenger flow forecast. Then for the special factors of passenger flow, we not only put forward a combination model of time series and regression analysis, but also introduce dummy variables and similar daily sample data for further improvement. The scheme realizes the high precision solution of the abnormal prediction problem. The simulation results show that this method has good applicability for the short-term forecasting of passenger flow. In particular, the comparison between the abnormal- state improved combination and the single time series model with the same samples and forecast cycle shows that the improved model can be applied to passenger flow predictions including the inherent nature of time invariant and special factors which has strong adaptability and better prediction accuracy. Copyright © 2017 by Science Press.


Luo X.,China Academy of Railway Sciences | He F.,China Railway Southeast Research Institute Co.
Modern Tunnelling Technology | Year: 2014

Water bursts are one of the most serious geological disasters that can occur during the construction of long deep-buried tunnels, and their occurrences are closely related to the aquifer ahead of the working face or outside the free face. In this paper, the causes of water burst occurrences in long deep-buried tunnels are analyzed. Five kinds of structures and models are systematically presented: a highly fractured zone at upper wall of an uncemented and water-rich compressive fault; an uncemented and water-rich tensional fault zone; an uncemented and water-rich faulted bedding plane (a closely jointed rock mass); water-filling karst; and an underground water-bearing syncline structure and its water burst model. Moreover, disasters that occurred in five kinds of structures are analyzed through examples.


Chunyu S.,China Academy of Railway Sciences
MATEC Web of Conferences | Year: 2016

Copper doped TiO2 by the method of sol-gel preparation was conducted to stimulate the TiO2 visible light response and enhance the performance of photocatalytic degradation. By XRD, SEM and EDS analysis, molar ratio of 1.0%, 1.5%, 2.0% and 1.0% Cu doped TiO2 presented smaller grain sizes (20-50 nm) than German P25 TiO2 (50-100 nm). Especially, 1.5% Cu doped TiO2 presented the highest and finest degree of crystallinity from XRD peak. Its reunion phenomenon was the weakest among all Cu doped TiO2. Combined with Cu doping structure, micro stress changes as well as the performance of the degradation of nitrobenzenes (NBs), the optimum mol ratio of Cu doped TiO2 was 1.5%. With 1.5% Cu doped TiO2 for 180 min UV light degradation of NBs, the removal efficiency was 60.02%, two times higher than that of Germany P25 TiO2. The reaction of NBs photocatalytic degradation by CuxTi(1-x)O2 followed first order kinetics. Synthetically, SEM, ESD and performances of NBs degradation confirmed that the optimal formula of CuxTi(1-x)O2 for degradation of NBs was Cu0.0183Ti0.9817O2. © The Authors, published by EDP Sciences, 2016.


Li Q.,Beijing Jiaotong University | Ren S.,China Academy of Railway Sciences
IEEE Transactions on Systems, Man and Cybernetics Part C: Applications and Reviews | Year: 2012

Discrete surface defects are the most common anomalies of rails and they should be carefully inspected. However, it is a challenge to detect such defects in a vision system because of illumination inequality and the variation of reflection property of rail surfaces. This paper presents an intelligent vision detection system (VDS) for discrete surface defects and focuses on two key issues of VDS: image enhancement and automatic thresholding. We propose the local Michelson-like contrast (MLC) measure to enhance rail images. MLC-based method is nonlinear and illumination independent; therefore, it notably improves the distinction between defects and background. In addition, we put forward the new automatic thresholding method-proportion emphasized maximum entropy (PEME) thresholding algorithm. PEME selects a threshold that maximizes the object entropy and meanwhile keeps the defect proportion in a low level. Our experimental results demonstrate that VDS detects the Type-II defects with a recall of 91.61% and Type-I defects with a recall of 88.53%, and the proposed MLC-based image enhancement method and PEME thresholding algorithm outperform the related well-established approaches. © 1998-2012 IEEE.


Wang L.,China Academy of Railway Sciences
Zhongguo Tiedao Kexue/China Railway Science | Year: 2011

From the point of methodology view, this paper systematically researches the ideas and principles when establishing the testing and commissioning methods for high speed railway by using the meta-synthetic engineering from the qualitative method to the quantitative method. It brings forward that the structured lifecycle for high speed railway is composed of such phases as system layout, analysis, design, implementation, testing and commissioning, operation testing, operation and maintenance, etc.. The relationship between the system test and overall system testing and commissioning in high speed railway is put forward based on the dialectical entity method of holism and reductionism. Taking the step by step speed-up test as an example, the systemic examination method of high speed railway testing and commissioning based on the synthesis integration method of meta-synthetic engineering from the qualitative to the quantitative is expounded. A comprehensive evaluation system of the high speed railway lifecycle is constructed by using the comprehensive evaluation method based on WSR methodology.


Tao X.,China Academy of Railway Sciences
Zhongguo Tiedao Kexue/China Railway Science | Year: 2013

In order to study the influence of different structures on the stress and the fatigue performance of orthotropic steel bridge deck, three section models were designed and the static and fatigue tests were carried out. Results show that the thickness of bridge deck has significant influence on the stress of the attachment weld between bridge deck and U rib. We suggest that the thickness of bridge deck should be more than 14 mm. The spacing of diaphragm plates directly influences the out-of-plane stress of the intersection between diaphragm plate and U rib attachment weld, the out-of-plane deformation of diaphragm plate and the vertical deformation of middle U rib. The stress of arc opening decreases with the increase of the thickness of diaphragm plate. The crack of orthotropic steel bridge deck caused by secondary stress grows slowly, and will not directly affect the bearing capacity of the whole bridge deck. It is disadvantageous to the fatigue performance of orthotropic steel bridge deck that welding holes are left in the upper intersection between the diaphragm plate and U rib.


Yu H.,China Academy of Railway Sciences
Zhongguo Tiedao Kexue/China Railway Science | Year: 2013

In order to treat the diseases (such as base subsidence and mud pumping) in tunnel under the condition of heavy axle load train on certain existing railway, drilling combined with geophysical drilling detection methods were used for detecting the disease section of tunnel. Detection results show that the base plate of tunnel disease section is plain concrete and is thinner (25 cm or so). There is a weak interlayer of about 5 cm between the bedrock and concrete. The water content of the base in disease section is greater, which causes serious damage of base plate concrete. On the basis of mastering the present situation of tunnel base, treatment measure by combining well point dewatering and grouting is put forward. Through theoretical calculations, the numerical analysis of dewatering effect, construction feasibility analysis, and taking into account construction costs, the specific programs are determined as follows. Unilateral dewatering is adopted, and then well point system will be arranged in the lateral line of heavy vehicle. Fifty well points will be laid in 100 m disease section with the spacing of 2 m. Grouting is carried out at both ends of the sleeper in heavy vehicle line. Grouting pipe diameter is 60 mm, length is 2.0 m, spacing is 1.0 m, and grouting pressure is 0.3 MPa. After the treatment measure by combining well point dewatering and grouting has been implemented, the water level of the tunnel base in this section always keeps at about 1.5 m under the base. No such diseases as base subsidence and mud pumping occur, which indicates that the measure is very effective.


Li Q.,Beijing Jiaotong University | Ren S.,China Academy of Railway Sciences
IEEE Transactions on Instrumentation and Measurement | Year: 2012

Discrete surface defects impact the riding quality and safety of a railway system. However, it is a challenge to inspect such defects in a vision system because of illumination inequality and the variation of reflection property of rail surfaces. This paper puts forward a real-time visual inspection system (VIS) for discrete surface defects. VIS first acquires a rail image by the image acquisition system, and then, it cuts the subimage of rail track by the track extraction algorithm. Subsequently, VIS enhances the contrast of the rail image using the local normalization (LN) method, which is nonlinear and illumination independent. At last, VIS detects defects using the defect localization based on projection profile (DLBP), which is robust to noise and very fast. Our experimental results demonstrate that VIS detects the Type-II defects with a recall of 93.10% and Type-I defects with a recall of 80.41%, and the proposed LN method and DLBP algorithm are better than the related well-established approaches. Furthermore, VIS is very fast with a linear computational time complexity, and it can be in real time to run on a 216-km/h test train under our experimental setup. © 1963-2012 IEEE.


Patent
China Academy of Railway Sciences | Date: 2012-08-28

A ballastless track system comprises a base; a track slab arranged above the base; a poured-field layer arranged between the base and the track slab, the poured-field layer being formed by filling self-compacting concrete, emulsified asphalt cement mortar or resin mortar, and the inside of the poured-field layer being of a steel bar structure; a connecting piece, the first end of the connecting piece extending into the track slab, and the second end of the connecting piece extending into the poured-field layer; and two rows of rail-seat arranged on the track slab in parallel; and rails arranged on the rail-seat. The ballastless track system is high in reliability, good in durability, and easy in construction and maintenance.


Patent
China Academy of Railway Sciences | Date: 2011-12-15

Provided in the disclosure is a pre-stressed concrete track slab of slab-type ballast-less track, which includes a slab body (1), on which fastening embedded casings (4) are arranged. At least one row of longitudinal common steel bars (11) and at least one row of transverse common steel bars (12) are arranged in the slab body (1) along a length direction and a width direction. The longitudinal common steel bars (11) are insulated from the transverse common steel bars (12). At least one row of longitudinal pre-stressed steel bars (7) and at least one row of transverse pre-stressed steel bars (6) are fastened in the slab body (1) along the length direction and the width direction through anchor backing plates and fastener devices (8). In the pre-stress directions of the longitudinal pre-stressed steel bars (7) and the transverse pre-stressed steel bars (6), it is post-tensioned in both directions or it is pre-tensioned in one direction and post-tensioned in the other direction. Limiting structures (5) and grounding terminals (10) are also arranged on the slab body (1). The pre-stressed concrete track slab has the characteristics of light structural dead weight, small structure height, low manufacturing cost and deformation resistance.

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