Basic Reliability Structures of Complex Technical Systems - New Contributions in Information Systems and Technologies - page 314

Depending on the subject of system analysis the structure can reflect: the
general description of the system (general structure), the structure of the system
(constructional structure), the system (functional structure), the evaluation of
the technical condition (diagnostic structure) and the mapping of the technical
condition of elements on the state of the system (reliability structure).
In the paper, the system, which consists of machinery, equipment and technical
devices is called a technical system. In such a type systems, there is a clear
indication of machine and human activity directed at the exploit of resources,
phenomena and forces of nature. Each system reliability structure depends on:
- allocation of its constituent parts that was assumed in the analysis of the
system decomposition level;
- functional relationship between the elements of the system;
- adopted criteria to recognize down state of an element or system;
- functions carried out by the system.
System reliability structure can be represented using three other equivalent
methods [11]:
- positive, in which the analysis is directed to the description of the system
up state;
- negative, which boils down to the analysis of the description of the down
state of the system;
- combination (positive-negative) in which the analysis is carried out using
both the positive and negative description.
For each of these methods the following ways of the system reliability structure
description are provided:
- verbal description (in words);
- mathematical description (probabilistic or statistical methods, theory of ran-
dom functions);
- logic description (logical signs, logic, logic arrays, Venn diagrams).
Regardless of the above classification according to the paper [5] models of the
system structure can form:
- verbal description (verbal representation) of system forming relationship
without the use of drawings and mathematical relationships;
- graphic description, which is a schematic representation of the system using
the notations and symbols;
- analytical description (in mathematical form) describing the relationship
between the reliability state of elements and the reliability state of the whole
system;
- mixeddescriptionbasedonthecombined use of several of the mentioned
forms of the system description.
Different mathematical control models can be tested by means of reliability
structures, some of them will be considered in previously elaborated works e.g.
[5, 15-23].