The Information Brittleness Of Train Operation Control System In High-speed Railway

With the continuous construction of high-speed railway network, and the continuous improvement ofhigh-speed rail operating speed, the external environment of the high speed train operation control processes is increasingly complex;thesystem security requirements are more stringent. At the same time, the characteristics of high-speed train operation control process increase the security difficulty also.Specifically, the system has a huge number of sub-units, the information exchange relationship involves multiple levels and forms, and the system is open with the emergence of system development.Most of the existing study of train operation control procrssessafety is focused on subsystems and achieve security management by simulation or safety assessment based on reductionism. which is lack of system integrity.Based on the informational interrelationships between subsystems and subunits, this paper builds a high-speed railway train operation control process system involving Computer-based Interlocking subsystem, Cebtralized Train Control subsystem and Chinese Train Control subsystem. A new brittleness research method is put forward based on Petri net theory based on the connotation and characteristics of the complex system brittleness theory. Then the root causes of the system brittleness are analysised and the security management strategy is proposed from the perspectives of strutural brittleness and dynamic fuzzy brittleness. The specific implementation process is as follows:(1)Applicability of complex system brittleness theory. Brittleness is a system characteristic that when a subunit collapses, the consequence will spread based on the interalationship between subsystems and subunits until the whole system breaks down. Firstly, the brittleness method requirements is analysied based on the characterristics of high-speed train operation control processes. Through applicabilitu analysis of existing research methods such as entropy theory, cellular automata theory and catastrophe theory, this paper proposed a new research method of system brittleness based on Petri net theory.(2) Information processing modeling of high-speed railway train operation control system. Firstly,the characteristics of the high-speed train operation control process and the root causes of the system complex are analysed. Then aexperimental frame of high-speed railway train operation control system is built,and the original model building based on Coloured Petri net is completed using top-down modeling ideas.(3) Strutural brittleness analysis of high-speed railway train control process.The system structural brittleness takes anynode in state space as the brittleness sources, and the degree of the impact on the overall system function achievement.In structural brittleness, the brittleness transimits based on the association relationship betweent nodes in the state space. Firstly, the original model of high-speed railway train control system is transformed to an structural model based on the requirement of structural brittleness analysis. Then an emulated platform of system brittleness analysis is built based on Standard Modeling Languaage and C #.Finally, the brittleness degree and brittleness correlation of the subsystems or subunits are calculated and analyzed by the simulation.(4) Dynamic fuzzy brittleness analysis of high-speed railway train operation control system. The system dynamic fuzzy brittleness takes the depressed fuzzy reliability of the subsystem or subunits as the brittleness sources and the reliability continual accumulates based on the fuzzy proposition inference rules in Fuzzy Petri net. In dynamic fuzzy brittleness, the fuzzy brittleness transimits based on the connections between transitions and places until the comprehensive fuzzy reliability is lower than the minimum acceptance criteria. Firstly, the original model is transformed to a fuzzy model with fuzzy reliability factors. Then a quantitative approach to determine the fuzzy reliability of subsystems based on the conflict numbers or the failure numbers in real system. Lastly, a simulation in different fuzzy reliability combinations is down and the simulation results reflect the impact of subsystems or subunits on the overall function achievement when the fuzzy reliability of subsystems or subunits floats in different levels.(5) The brittleness safety supervision strategy of high-speed railway train operation control system. The brittleness safety supervision strategy is proposed from structural brittleness and dynamic fuzzy brittleness. Firstly, different monitors are set up in different stages of train operation control processes and the fuzzy reliability is supervised in real time in dynamic fuzzy brittleness. When the fuzzy reliability is lower than the minimum acceptance criteria, the system will send alerts and the restore from outside starts unitil the fuzzy reliability back to the original value. In structural brittleness analysis, the usual safety management level should match the brittleness index reaults such as brittleness degree or the brittleness correlation.In this paper, the brittleness character of the high-speed railway train operation control system is studied. The root causes of system brittleness are explained from the perspective of structural brittleness. And the real time monitoring of system fuzzy reliability is realized by setting up different monitors in different stages. The safety supervision strategies are also proposed. This research provides a new way of thinking for the safety supervision of the high-speed railway train operation control system.