Dependability in digital technology

Aim. The migration towards the Industry 4.0 digital technology will soon enable “right first time” (virtually with no material expenditures for experimental testing and subsequent design improvement) creation of increasing numbers of entities with unique application properties. Calculating the dependability indicators of such entities based on reliable statistical data will be greatly challenging. However, the need for dependable entities will remain. Additionally, the approaches to digital technology based on physical models and engineering knowledge enable the creation of predictive dependability methods (based on the assumption of non-acceptability or, contrarily, intentional programming of failures). That inevitably causes a paradigm shift in the modern dependability theory associated with a forced deviation from the mathematical models as the basis of the dependability theory. Methods. According to the Russian tradition, dependability is normally defined by specifying the required functions through a set of parameters that characterize the ability to perform them and the allowable variation limits of the parameter values. If the criteria of some required functions cannot be specified through parameters, a technique can be used, whereas the operation of the item is substituted with an information model in the form of a black box, in which the performance of the required functions is characterized by probabilistic indicators of failures (statistical, logical, Bayesian, subjective). In order to account for the parameters and probabilities of performance of the required functions in a coordinated manner, finding the values of the parameters within the allowed range can be characterized by the probability as the degree of confidence in the occurrence of such event, for example accounting for design reserves. In this case the performance of all the required functions can be characterized by an additive dependability indicator that is identified using the method of dependability structure diagram. This indicator completely characterizes the predicted dependability level. Results. Predicted dependability is estimated using the method of design engineering analysis of dependability (DEAD). This method allows using a set of algorithm-based techniques to present the design (per GOST 2.102) and process control (per GOST 3.1102) documentation for a technical item in the form of a generalized parametric model of operation. Such model allows taking into consideration the individual specificity of the design of entities based on the unity of functionality, operability and dependability, and thereupon estimating the probability of failures. DEAD and digital design algorithms are completely compatible and driven by common problems related to the substantiation of design solutions for the purpose of elimination (reduction of probability) of errors able to cause failures based on analytical, computational and experimental verification. Conclusions. Digital technology provides a tangible opportunity of predicting, reducing the impact or eliminating possible failures. That can be achieved through the same means that often cause failures, i.e. design engineering. For that purpose, it is required to create new applications of the modern dependability theory based on engineering disciplines and design engineering methods developed for ensuring quality and dependability of entities.

digital technology, dependability theory, dependability prediction, unique highly vital system, design engineering analysis of dependability (DEAD)

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