Software Tool for Manipulation with Decision Diagrams Used in Reliability Analysis

Reliability analysis of a system is a complex task that includes a lot of steps. Typical steps are creation of a mathematical model of the system, computation of global reliability characteristics, detection of circumstances under which a failure of the system can occur, quantification of importance of individual elements of the system, optimization of system reliability, etc. At our faculty, we have a course on reliability analysis. During the course, the students are taught how a mathematical model of a system can be created and how it can be analyzed. For this purpose, they use various mathematical apparatus, such as Boolean algebra, calculus, theory of probability and stochastic processes. During the lectures, the students are taught how these methodologies can be applied in reliability analysis, and during the practical classes, they apply this knowledge in analysis of real systems. However, real modern systems are usually composed of a lot of components, what makes their analysis impossible without a support software. Because of that, we decided to implement a software that makes laboratory classes less time consuming on routine calculations. This software has been developed in a frame of a project course at our faculty. In the current state, it allows creating various data structures for representation of the structure of a system and, based on them, compute global reliability characteristics, such as system availability and unavailability. From the existing structures, it mainly focuses on binary decision diagrams because they can be used to represent the structure of a system in an efficient way. The software allows its user to create a binary decision diagram, manipulate with its elements, export the diagram into PNG or SVG file format. Thanks to these and others, it allows students to understand work with binary decision diagrams, investigate their properties, and prepare graphical parts of a documentation for their term projects. Furthermore, the diagrams created using the software can also be used by the teachers of the course in preparation of learning materials for students of our faculty.