Beijing Jiaotong University , formerly Northern Jiaotong University , is one of the oldest universities in mainland China. The main campus is located close to Xizhimen, central Beijing. The university's abbreviated name which locals usually call it by is JiaoDa . JiaoDa is a participant in the Ministry of Education's Project 211. Wikipedia.
Beijing Jiaotong University | Date: 2017-07-12
A six degree of freedom laser simultaneous measurement system, wherein a laser emitting unit is separated from a fixed sensor head; the laser emitting unit is connected with the fixed sensor head by a single polarization maintaining fiber; a moving unit comprising the reflector and the beam splitter is mounted on the linear guide; utilizing of the single polarization maintaining fiber, which connects the laser emitting unit with the fixed sensor head, reduces the influence of heat generated by laser source on the measurement accuracy, and makes the system more compact and integrated. The six degree of freedom errors, including position error, horizontal and vertical straightness errors, pitch, raw and roll, can be measured simultaneously by only one incident light. The non-cable connection on the moving unit makes long-distance and in-situ measurement possible (Fig. 2).
Beijing Jiaotong University | Date: 2016-07-28
Embodiments of the present invention provide a train control method for maximizing utilization of regenerative energy. The method mainly comprises: working out a matching error T of a current matched pair of trains Mx (i, j) of a station in the current running situation; and comparing the matching error T with a preset maximum adjustable error T_(x )of the current matched pair of trains Mx (i, j) of the station and determining a strategy for adjusting train running of the current matched pair of trains Mx (i, j) according to comparison results.
Beijing Jiaotong University | Date: 2014-04-24
The present invention provides a failure logic modeling method for a high-speed railway train operation control on-board system, including the following steps: determining the functional relationship between the structure and the parts of the train control on-board system; analyzing the failures of the parts based on known failures of the train control on-board system in combination with brainstorming; establishing an FMEA table to generalize the failures of the parts; editing and simulating the failures by using a modeling tool. By adopting the present invention, the failure modes analyzed are more systematic, and the failure logic modeling can be carried out from a global perspective more easily, the whole process can be better targeted meanwhile, the security analysis complexity of the train control system will be effectively reduced and the development period of the train control system will be shortened.
Beijing Jiaotong University | Date: 2014-09-03
A six degree of freedom laser simultaneous measurement system, wherein a laser emitting unit is separated from a fixed sensor head; the laser emitting unit is connected with the fixed sensor head by a single polarization maintaining fiber; a moving unit comprising the reflector and the beam splitter is mounted on the linear guide; utilizing of the single polarization maintaining fiber, which connects the laser emitting unit with the fixed sensor head, reduces the influence of heat generated by laser source on the measurement accuracy, and makes the system more compact and integrated. The six degree of freedom errors, including position error, horizontal and vertical straightness errors, pitch, raw and roll, can be measured simultaneously by only one incident light. The non-cable connection on the moving unit makes long-distance and in-situ measurement possible.
Agency: European Commission | Branch: FP7 | Program: CP-IP | Phase: SST.2010.1.1-3. | Award Amount: 4.90M | Year: 2011
As pointed out in the White paper for European transport the aim of the European rail operators is to increase the market share of goods traffic from 8 % in 2001 to 15 % in 2020. The nightly time slots will play an important in this. Railway vibration annoyance and sleep disturbance in residential areas is a potential show stopper for this increase. Therefore the aim of Cargovibes is to develop and assess measures to ensure acceptable levels of vibration for residents living in the vicinity of freight railway lines in order to facilitate the extension of freight traffic on rail. Existing evaluation criteria in use are deemed too strict and not based on relevant surveys. There are no uniform assessment methods available and knowledge about mitigation measures is fractured and hardly common. In this proposal the right criteria will be established, given the characteristics of freight traffic. Existing mitigation measures for conventional railway are not directly applicable to freight trains which generate a different soil vibration pattern than conventional railways in terms of vibration amplitudes and frequency contents. Viable efficient new mitigation measures for freight rail traffic will be designed and validated. In operational terms the project aims at developing a) criteria for the evaluation of the adverse effects. These criteria will be formulated as extensions of current guidelines. b) a protocol for the assessment of the effect of mitigation measures. c) three new mitigation measures: a measure for the rolling stock, one for the track and one in the propagation path. These measures will be pilot tested and validated in service. d) catalogue of mitigation measures, for use of railway community. To ensure that the project will generate products that can readily put to use, a Board of End Users will be put into place which will judge intermediate results and guide the developments in the course of the project.
Liu Z.-B.,Beijing Jiaotong University
Optics Express | Year: 2014
This paper firstly demonstrated the refractive index (RI) characteristics of a singlemode-claddingless-singlemode fiber structure filter based fiber ring cavity laser sensing system. The experiment shows that the lasing wavelength shifts to red side with the ambient RI increase. Linear and parabolic fitting are both done to the measurements. The linear fitting result shows a good linearity for applications in some areas with the determination coefficient of 0.993. And a sensitivity of ∼131.64nm/RIU is experimentally achieved with the aqueous solution RI ranging from 1.333 to 1.3707, which is competitively compared to other existing fiber-optic sensors. While the 2 order polynomial fitting function, which determination relationship is higher than 0.999, can be used to some more rigorous monitoring. The proposed fiber laser has a SNR of ∼50dB, and 3dB bandwidth ∼0.03nm. © 2014 Optical Society of America.
Chen J.,Beijing Jiaotong University
The British journal of nutrition | Year: 2012
The aim of the present study was to investigate the effects of Bifidobacterium adolescentis (Bif) supplementation on visceral fat accumulation and insulin sensitivity of the metabolic syndrome in HF-diet-fed rats. Adult male Wistar rats (n 10 per group) were fed four different experimental diets for 12 weeks as follows: standard diet; high-fat (HF) diet; a mix of HF diet and Bif; a mix of standard diet and Bif. Liver, mesenteric fat, epididymal fat, retroperitoneal fat, and inguinal fat, pancreas and triceps surae in all four groups of the rats were weighed, while liver steatosis and insulin sensitivity were evaluated at the end point of the study. As the number of intestinal Bifidobacterium species decreased obviously, fat pad weight and body weight increased significantly in the HF group compared with in the other three groups (P <0·05). Addition of Bif led to a reduction in body weight and fat pad weight (P <0·05). With an increase in liver weight, more severe steatosis of hepatocytes was observed in the HF group compared with in the other three groups. A significant decrease of the glucose infusion rate and pancreas weight was found in the HF group (P <0·05). This deleterious effect was alleviated when Bif was added to the diets. Bifidobacterium supplementation ameliorated visceral fat accumulation and insulin sensitivity of the metabolic syndrome in HF-diet-fed rats.
Lu X.,Beijing Jiaotong University
Chaos | Year: 2013
A spectral problem, the x-derivative part of which is a simple generalization of the standard Ablowitz-Kaup-Newell-Segur and Kaup-Newell spectral problems, is presented with its associated generalized mixed nonlinear Schrödinger (GMNLS) model. The N-fold Darboux transformation with multi-parameters for the spectral problem is constructed with the help of gauge transformation. According to the Darboux transformation, the solution of the GMNLS model is reduced to solving a linear algebraic system and two first-order ordinary differential equations. As an example of application, we list the modulus formulae of the envelope one- and two-soliton solutions. Note that our model is a generalized one with the inclusion of four coefficients (a, b, c, and d), which involves abundant NLS-type models such as the standard cubic NLS equation, the Gerdjikov-Ivanov equation, the Chen-Lee-Liu equation, the Kaup-Newell equation, and the mixed NLS of Wadati and/or Kundu, among others. © 2013 AIP Publishing LLC.
Beijing Jiaotong University | Date: 2015-11-27
The invention discloses a complex network-based high speed train system safety evaluation method. The method includes steps as follows: (1) constructing a network model of a physical structure of a high speed train system, and constructing a functional attribute degree of a node based on the network model; (2) extracting a functional attribute degree, a failure rate and mean time between failures of a component as an input quantity, conducting an SVM training using LIBSVM software; (3) conducting a weighted kNN-SVM judgment: an unclassifiable sample point is judged so as to obtain a safety level of the high speed train system. For a high speed train system having a complicated physical structure and operation conditions, the method can evaluate the degree of influences on system safety when a state of a component in the system changes. The experimental result shows that the algorithm has high accuracy and good practicality.
Beijing Jiaotong University | Date: 2014-12-05
The present invention provides a fault prediction and condition-based repair method of an urban rail train bogie. An optimum service life distribution model of a framework, a spring device, a connecting device, a wheel set and axle box, a driving mechanism, and a basic brake device of a bogie is determined by adopting a method based on survival analysis; a reliability characteristic function of each subsystem is obtained; then, a failure rate of each subsystem of the bogie is calculated by adopting a neural network model optimized by an evolutionary algorithm; and finally, proportional risk modelling is conducted by taking the failure rate and safe operation days of each subsystem of the bogie as concomitant variables; and on the basis of cost optimization, thresholds and control limits for condition-based repair of a bogie system are obtained.