Threat protection pair as a parameter of object security and risk assessment

[b]Abstract[/b]. The paper presents a concept of threat protection pairs as virtual elements of a structure of an object, to indicate its potential capacity to safeguard against specific risks. Neutrality of the pair occurs in a situation of full calm or full protection against the threat assigned to this situation. Degrees of the neutrality violation (defined by the probabilities) are the inputs to determine: the object security and the risk of servicing and risk of compensation for the downtime. It can be noted that the results of the work may be used for many other issues, e.g. to optimize the full conditional programs for diagnosing.[b]Keywords[/b]: threat protection pair, security, risk of servicing, risk of compensation for the downtime, diagnostics program, invasion, faul