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Beijing, China

Zhou W.,National Institute of Design | Cheng X.,Indian Ministry of Railways | Cheng X.,C3 Group | Zhao H.,National Institute of Design | Wang S.,Tsinghua National Laboratory for Information Sciences and Technology
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

In order to solve the problem of the static test methods which execute test according to the fixed test sequence set, this paper proposes a dynamic test method for the testing of train control system. This method uses the test results obtained from the last test sequence execution as the feedback for the next test sequence selection to set up a testing close loop. If there was no fault detected after executing one test sequence, the test actuator executes the following test sequence. If faults were detected, the test actuator updates the test model of the system under test and generates new test sequence set according to new test model and test aim with the least cost, and then executes test according to new test sequence set. The simulation results show that the effective test efficiency and test coverage rate have been evidently increased by the dynamic test method, and no fake test results were given during the testing. Source

Li K.,Beijing Jiaotong University | Li K.,C3 Group | Xu T.,Beijing Jiaotong University | Tang T.,Beijing Jiaotong University
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

The coordination between the on-board equipment of Chinese Train Control System Level 3 (CTCS-3) and the Radio Block Center (RBC) is realized by the collision avoidance protocol (CAP). According to the safety requirement for train collision avoidance, the model of CAP is represented by safety use case diagram and safety class diagram in the safety UML to implement the following safety functions: the train speed can never exceed the desired speed in any interval and the train position is never beyond the end of Movement Authority(MA). The safety function of CAP is implemented by the formal refinement of the continuous and discrete collision avoidance strategies. The former gives the static structure, the dynamic interaction and the continuous control strategy of CAP in the case that the speed and the position of the train are continuous variables. Otherwise, the latter has achieved the discretization for the continuous collision avoidance strategy by discrete logic. The CAP real-time program code is generated through the further refinement of the discrete collision avoidance strategy. The correctness and the safety of the refinement for the continuous and discrete collision avoidance strategies as well as the final code generation have been guaranteed by the rigorous reasoning based on the formal logic-Weakly monotonic time extension of iterative Duration Calculus (WDC*). Source

Cai B.,Beijing Jiaotong University | Liu D.,Indian Ministry of Railways | Liu D.,C3 Group | Shangguan W.,Beijing Jiaotong University | And 3 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

Based on multi-resolution modeling and High Level Architecture (HLA), CTCS-3 train control system simulation was studied. According to the structure of CTCS-3, four key modules including Radio Block Center (RBC), train control center (TCC), the balise information transmission module and the on-board vital computer were chosen to constitute the train control model. Based on the difference of the information transmission level, using multi-resolution modeling method, the different modules of train control model were divided into high, middle and low resolution module. The HLA simulation technology was used to construct the property publication and the ordering relationship of train control model federation object module and federation member, and the train control simulation process was realized with RTI software. The simulation realized the following simulation scenes, which included the connection and disconnection of the train control model and RTI software, the movement authorization generation realized by RBC and TCC in different resolution, the on-board vital computer computed object distance curve and train running view display, etc. The simulation results have validated the feasibility of the multi-resolution modeling method in CTCS-3 simulation. Source

Xiong L.,Beijing Jiaotong University | Lu X.,Indian Ministry of Railways | Lu X.,C3 Group | Zhong Z.,Beijing Jiaotong University | And 2 more authors.
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

According to the characteristics of the wireless channel and the scenarios of high-speed railway, this paper introduces the methods of small-scale fading modeling with various scenarios for the wireless channel of high-speed railway GSM-R system. With the methods for modeling, the parameters of high-speed railway small-scale fading channels in time domain and frequency domain, such as the delay spread, the coherence bandwidth, the level crossing rate and the coherence time, are quantitatively discussed with simulation and computing. The Hard-In-the-Loop (HIL) simulation test bench for high-speed railway GSM-R communications system is built, and the performance of high-speed GSM-R system is evaluated. The simulation and experimental results show that the communication quality will decline at different degrees with the increase of the running speed. The communication quality in the downlink at the train speed of 350 km · h-1 is worse than that at 80 km · h-1 to a certain extent. Whereas, it still can meet the requirement of GSM-R system, which indicates that the communication quality of high-speed railway is guaranteed. However, the communication quality will deteriorate seriously at 500 km · h-1. To improve the design of the receiver is the key to solving the problem of communication quality deterioration. Source

Wu D.,Beijing Jiaotong University | Xiong J.,Indian Ministry of Railways | Xiong J.,C3 Group | Zhu G.,Beijing Jiaotong University | Zhong Z.,Beijing Jiaotong University
Zhongguo Tiedao Kexue/China Railway Science | Year: 2010

According to the theory of John Berry, the moment method was adopted to compute the site attenuation (SA) through establishing a simulation model of a test site based on the equivalent circuit of the specific balun. The differences (ΔSA) between the simulated SA of an actual site and the SA of the ideal site was used as the correction values for correcting the measured SA on the actual site. The influences (ΔSA) of the site size, the controlling room and the lightening rods on SA were computed respectively. The integrated influence of all factors was computed too. The simulated SA of the actual site was compared with the measured SA. Results show that these three factors all have effect on SA. The maximum difference (ΔSA) is up to 0.74 dB. The computed ΔSA can be considered as the correction of the measured SA on an actual test site. The computed SA basically agrees with the measured SA of the actual site, which demonstrates the effectiveness of the proposed method. Source

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