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Zhang G.,Xian Railway Vocational and Technical Institute | Li Q.,Southwest Jiaotong University
Dianli Zidonghua Shebei/Electric Power Automation Equipment | Year: 2012

The out-phase power supply is transferred to in-phase power supply by applying additional breakers and converters to original structure and lines of traction substation. The phases of traction voltage become consistent by switching on/off the breakers. The converter is used as balancing device. Single-phase back-to-back converter is applied when the phase difference between two ports is ±90°, while three-bridge three-terminal or three-bridge four-terminal converter is applied according to the connection mode when the phase difference is ±120°. The expected compensative current is generated by the balancing device according to the given formula to avoid the superposition of negative currents caused by in-phase power supply. Simulative results show that, the three-phase current of power system is the superposition of the sine fundamental wave and the high-frequency modulation wave, which is in-phase with the voltage.


Liu X.Q.,Xian Railway Vocational and Technical Institute
Applied Mechanics and Materials | Year: 2014

Aggressive train signal belongs to typical accidents in the process of train running; it has many influence factors, widely related departments and complex results. In this paper, we carry on the qualitative and quantitative analysis on the typical accidents using FTA technology, to estimate and calculate the structure, probability and critical importance degree. The affecting factor of the typical accident to analysis deeply. Then the analysis conclusion is carried out and the prevention strategies of the typical accident are given. © (2014) Trans Tech Publications, Switzerland.


Xu X.,Xian Railway Vocational and Technical Institute
ICTE 2011 - Proceedings of the 3rd International Conference on Transportation Engineering | Year: 2011

According to features of the high speed railway and based on accident-causing theory, the influence factors and construction goal of high-speed railway security system were analyzed from human, machine and operation environment, the three-level security system of high-speed railway was constructed using system engineering. Moreover, function of high-speed railway security information system as well as structure and function of disaster prevention safety monitoring subsystem were analyzed. In order to ensure reliability of high-speed railway security system, long-effect mechanism should be taken to be the breakthrough point, as strong motivation and hard constraint to worker for improving work quality. Fundamentally strengthen the equipment quality to improve equipment reliability and finally ensure security. © 2011 ASCE.


Feng G.,Xian Railway Vocational and Technical Institute
Journal of Convergence Information Technology | Year: 2012

This paper proposes a method to improve the profile and eliminate the shadow and noises. First identify the changing area of the moving target by using difference of five-frame grads image and then perform "or" computing with the results obtained by the background difference method to get the complete profile of a moving target. We analyze the feature of the shadow in HSV color space to eliminate the shadow and eliminate the noises by the distribution features of the noises. The processing results indicate that the processing speed is 20ms/frame and the real-time requirement is met. The obtained moving target eliminates the shadow and noises and is very robust.


Tan X.R.,Xian Railway Vocational and Technical Institute
Advanced Materials Research | Year: 2014

With the transformation of China's urbanization and accelerated pace of urban agglomeration, increasing construction waste has brought the conflict between the development of urban and environmental degradation. To use recycled aggregate(RA) to a certain extent eased pollution on the environment. Because of the source of RA cause exist quality poor stability, dispersion and other shortcomings. By test, comparative analysis the differences indicators between recycled aggregate and natural aggregate, brick gravel content of recycled coarse aggregate performance indicators in particular made a crushing value performance test. As the research properties of recycled aggregate and adapted to the local grading standards provide a frame of reference. © (2014) Trans Tech Publications, Switzerland.


Zhao X.,Xian Railway Vocational and Technical Institute
Applied Mechanics and Materials | Year: 2012

To compare the similarities and differences between BLDCs and PMSMs firstly, then to present the theory of back-EMF zero-crossing rotor position detection. To propose the control scheme using 56F8013 based on back-EMF method. Finally investigate the research prospect of BLDCS. © (2012) Trans Tech Publications.


Fan X.,Xian Railway Vocational and Technical Institute
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2013

In distributed wireless network, the performance of random access protocol is not so good due to the lack of the central control on base station, therefore, how to improve this performance has always been the research hotspot being widely concerned. This article introduced and analyzed the random multi-access protocol at S-Aloha in detail, proposed an effective multi-queue model applied to random access protocol, made a further theoretical and simulation analysis on the proposed protocol, finally give out the analysis results. With the help of this theoretical analysis and simulation result, it proved that the improved random access protocol and multi-queue model can greatly improve the overall performance of the network. © 2013 SPIE.


Xing H.,Xian Railway Vocational and Technical Institute
Proceedings - IEEE 2011 10th International Conference on Electronic Measurement and Instruments, ICEMI 2011 | Year: 2011

In rail transit, sensor is the main measuring tool in speed measurement and location system, which consists of Electromagnetic induction sensor, Pulse speed sensor, Accelerometer and Inertial transducer, etc. Based on the comprehensive analyses of working principle, estimating mode and installed-application of sensors, this paper reaches the conclusion that integrated Multi-sensor can provide the most accurate speed positioning data, and through the data fusion algorithm train operation control is completed; rail traffic detecting technology will be the inevitably developing tendency in future. © 2011 IEEE.


Xing H.,Xian Railway Vocational and Technical Institute
Advanced Materials Research | Year: 2012

The present study explores the access of subway integrated supervisory and control system and all levels of mechanical and electronic subsystems, and discusses the network structure scheme of subway integrated supervisory and control system. After analyzing the merits and disadvantages of all kinds of network structures, the networking problem in subway integrated supervisory and control system that needs urgent solution has been raised. © (2012) Trans Tech Publications, Switzerland.


Xing H.,Xian Railway Vocational and Technical Institute
Applied Mechanics and Materials | Year: 2013

The present study analyzes some problems of the current higher vocational education on urban rail transit by investigating personnel cultivation of rail transit in higher vocational colleges in China. Subsequently, the researcher deeply discusses the following aspects: speciality establishment, curriculum system construction, systematic textbooks, teaching format, practice and internship equipment, faculty troop, cooperation between colleges and enterprises etc. Finally, the result reveals that the current situation of urban rail transit in higher vocational education is not optimistic, and needs to be reformed. © (2013) Trans Tech Publications, Switzerland.

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