• Netes V.A.
  SUSTAINABLE EFFICIENCY RATIO AS AN INDICATOR OF RELIABILITY OF COMPLEX SYSTEMS

The key indicator for estimating the reliability of complex systems is a ratio of sustainable efficiency that characterizes the impact of failures on the efficiency of a system’s application. The paper studies the definition and basic properties of this indicator, its application for various classes of systems, general methods of its calculation, decomposition of systems.
Keywords: complex system reliability, partial failures, sustainable efficiency ratio, classification of systems, calculation methods, decomposition of systems.

• Varzhapetyan A.G., Ivanov N.N., Strelnikov V.P.
  EVALUATION OF DURABILITY OF SOLDERED JOINTS USING DIFFUSED NONMONOTONIC DISTRIBUTION

The paper presents a technique for estimating the durability of soldered joints according to results of failure-free extreme tests. The major initial data are characteristics of constituent processes of soldered joints degradation (E_aj, P_oj, V_oj) which define accuracy of calculated reliability parameters.
Keywords: failure, durability, durability distribution, activation energy, high acceleration factor.

• Pereguda A.I., Pereguda A.A.
  MATHEMATICAL MODEL OF CUMULATIVE CHANGING OF THE KEY AVAILABILITY PARAMETER OF A PRODUCT FUNCTIONING UNDER CONDITIONS OF CYCLIC DISTURBANCES

The paper presents a mathematical model of cumulative changing of the key availability parameter of a product affected by cyclic shock loads. It considers ratios allowing parameters of product reliability and durability to be calculated. The exponential estimate of a failure-free operation probability has been proposed. The paper also gives an example of obtaining parameters of reliability and durability for water-wall tubes of gas and oil-burning steam generators of a thermal power station (GRES).
Keywords: damage accumulation, shock load, distribution of random variables sums, reliability parameter, durability, evaluation of mean value, shock.

Functional reliability. The theory and practice

• Shubinsky I., Schäbe H.
  ON THE DEFINITION OF FUNCTIONAL RELIABILITY

The theory of reliability has been developed in order to ensure the availability of technical objects (components and systems). However, no thorough explanation of the term "functional reliability" is given by now, although it has been used increasingly. We deduce a definition based on the terms of property, quality and function, while we draw attention to the principal differences between functional and structural reliabilities. We explain similarities between functional safety and functional reliability and show how their properties smoothly transit into each other.
Keywords: functional reliability, reliability, safety, quality, function.

• Yakovlev V.A., Adadurov A.S.
  METHOD OF SAFE DATA TRANSMISSION TO TRAIN BASED ON THE «SECRET SHARING» PRINCIPLE USING ADDITIONAL CHANNELS

The paper presents a method of secured data transmission to train using additional channels formed by audio frequency track circuits, spot radio transmitters (Eurobalises), inductive loops (Euroloop). The method is based on the «secret sharing» principle that assumes a transmitted message to be a set of individual secrets (fragments), with each of them transmitted to train when it passes through a block section (radio transmitter, Euroloop). To reconstruct a secret, it is required to receive correctly any M fragments from N transmitted fragments. The intruder has no opportunity to restore the message or to impose a false message by controlling V<M block sections (radio transmitters). Efficiency parameters and criteria of the proposed method of information protection have been introduced. Issues related to the increase of reliability of individual secret transmission based on jamproof coding have been studied in detail, and some ways for the optimization of method parameters have been provided.
Keywords: secret sharing, audio frequency track circuits, Eurobalises, jamproof coding, automatic block system.

• Frank P.A. Coolen
  NONPARAMETRIC PREDICTIVE INFERENCE IN RELIABILITY AND RISK: RECENT DEVELOPMENTS

During the last two decades, statistical methods using lower and upper probabilities have become increasingly popular. One such method is Nonparametric Predictive Inference (NPI), which makes relatively few modeling assumptions. Due to the specific nature of many reliability and risk scenarios, NPI provides attractive new solutions to many problems in these fields. This paper provides an introductory overview to this area, including examples on competing risks, system reliability and prediction of unobserved or even unknown failure modes.
Keywords: сompeting risks, imprecise reliability, lower and upper probability, nonparametric predictive inference, system reliability, unobserved or unknown failure modes

Functional safety

• Zamyshlyaev A.M., Ermakov A.O., Novozhilov E.O.
  METHOD OF MANAGING THE RELIABILITY AND FUNCTIONAL SAFETY OF RAILWAY FACILITIES BASED ON RISK EVALUATION

The state-of-the-art concept of railway infrastructure facilities maintenance assumes evaluating the technical state of a facility by its reliability parameters. The main drawback of a widely used method of evaluating a facility state based on fail-safety parameters (failure numbers, failure rates) is that the evaluation does not take into account the impact of facility failures on transportation process.
This paper presents a method allowing to manage the reliability and safety of infrastructure facilities maintenance, with the risk of train delays taken into account, which is based on the use of a facility downtime rate applied for the evaluation of its technical state.
Keywords: downtime rate, transportation process, train delay, decision-making scenario.