IMPROVEMENT OF THE PROCEDURE FOR SEARCHING RATIONAL TIME RESERVES FOR RECOVERY OF TRAIN MOVEMENT OF DIFFERENT CATEGORIES

This article improves the procedure for finding rational time reserves for theresumption of trains of different categories depending on the number of detained trains on the basisof the epidemiological SIR-model. A modified epidemiological SIR-model has been implemented forthe experimental railway line, which allows to take into account the interaction of trains of differentpriorities in the train schedule and the possibility of resumption of delayed trains due to the set timereserve. The adjustment of the delay rate transfer coefficients on the real data of train delays at theline has been performed. The solution of the system of differential equations of the SIR-model isproposed to be performed by the numerical Runge-Kutta method of the 4th order. Experimentalstudies of the impact of passenger train delays on the reliability of the regulatory schedule havebeen conducted. Experimental studies of the impact of passenger train delays on the reliability ofthe regulatory schedule have been conducted. The dependences of the number of detained trains ofdifferent categories on the change in the amount of time reserve for the resumption of trains ofdifferent categories are obtained. Rational time reserves for passenger, suburban and freight trainshave been established. These results were expertly assessed and confirm the adequacy of theobtained decisions in the practice of developing a regulatory schedule of trains at JSCUkrzaliznytsia. The application of the proposed approach will automate the complex process offinding rational values of compensation time in the threads of trains of different categories on therailway line and, as a consequence, increase the level of reliability of the regulatory train schedule.

EFFICIENCY OF COMPUTER NETWORKS WITH SDN IN THE CONDITIONS OF INCOMPLETE INFORMATION ON RELIABILITY

The paper analyzes the effectiveness of computer networks with SDN in conditions of incomplete reliability information. In order to ensure the specified indicators of the reliability of the computer network, it is recommended to use their guaranteed estimates. To increase the level of security of information systems and introduce the concept of time reserve in the process of packet transmission, it is necessary to separate the functions of traffic transmission from management functions. This is the basic principle of SDN. When using SDN technology in computer networks, it is possible to enter a time reserve when transmitting messages. This makes it possible to more accurately determine the reliability. The evaluation of the data transmission system of the computer network takes into account the possibility of entering a time reserve and obtained the basic calculated ratios for reliability indicators in terms of incomplete information about their distribution laws. A priori information is limited by knowledge of the first initial moments of mathematical expectation and variance. These results are a justification for the structure of computer networks that are designed or upgraded. You can also use this information to build highly reliable networks or technical facilities that exist in a single implementation.

Hidden Markov Model of Two-Component System with Group Instantly Replenished Time Reserve

Most systems allow the construction of a semi-Markov model. However, during the operation of the system, full information contained in the state encoding is not always available, but it is possible to obtain some signal (information). Tasks arise to assess the consistency of the model with the received data (signals), to refine the model and its parameters. Such parameters can be characteristics of random values characterizing system operation, time reserve value, etc. The theory of hidden Markov models allows solving these problems. In order to move from a semi-Markov model of the system to its hidden Markov model, it is proposed to first the semi-Markov model merge using a stationary phase merging algorithm. In this paper, on the basis of the semi-Markov model with a common phase state space of a two-component system with a group instantly replenished timereserve, we construct a hidden Markov model of a two-component system with a group instantly replenished time reserve. It is used to evaluate the characteristics and predict the states of the system in question based on the received vector of signals. The influence of the time reserve value on the probability of occurrence of the obtained vector of signals is shown.

TWO–COMPONENT RESTORABLE TOOL SYSTEM MULTI–PURPOSE MACHINE WITH AN INSTANTLY REFILLED TIME RESERVE

The object of the research is the technical system of a multipurpose machine tool, the tools of which can fail and be restored. A failed tool remains functional for some time due to a temporary reserve until a parametric failure occurs, the magnitude of which is random. All random variables describing the system have general distributions. The apparatus for constructing a mathematical model of the described system is a semi–Markov process with a discrete–continuous phase space of states. The stationary distribution of the embedded Markov chain is found explicitly. For systems with parallel connection, series connection with disconnection and without disconnection of elements, the stationary time between failures of the system, the stationary time spent in the state of failure and the stationary system availability factor are found. A numerical example shows the dependence of the stationary characteristics of the system on the size of the time reserve.