David Durán Pérez
DMD Solutions (Spain)
Development and implementation of a Direct Evaluation solution for Fault Tree Analyses competing with Minimal Cut Sets methods
Fault Tree Analysis (FTA) is a well-established technique to analyze the safety risks of a system. Two prominent FTA methods in aerospace are the so-called Minimal Cut Sets (MCS), which uses an approximate evaluation of the problem, and the Direct Evaluation (DE), which uses a top-down recursive algorithm. The first approach is valid for small values of basic event probabilities and has historically yielded faster results than exact solutions for complex fault trees. The second one means exact solutions at a higher computational cost.
Several research lines have been followed in order to improve the computing performance of both approaches. Firstly, improvements to MCS have been performed, where the main idea has been to optimize the number of required permutations and to take advantage of the available information from previous solved subsets. Secondly, improvements to DE have been developed, which deal with a reduction of the number of recursive calls through a deep search for independent events.
Additional implementation improvements have been applied regarding hash tables, memory access and usage, but also implementing the so-called “virtual gates”, which enable limitless children on each gate. The results presented hereafter are promising, not only because they show that both approaches have been highly optimized compared to the literature, but also because a Direct Evaluation solution has been achieved, which can compete in computational performance with MCS.
David has extensive experience in Reliability, Safety, Cybersecurity and Maintainability projects for the Aerospace industry. He joined DMD Solutions’ team in mid-2016 and has been giving training and consulting services for ED-202A, ED-203, ED-204, ARP4761, ARP4754A, DO-178C (Airborne SW) and DO-254 (Complex HW) certification processes in the framework of CS-23, CS-27, CS-25, CS-LUAS and CS-LURS. David’s hands-on background in Safety & Reliability analysis has acquainted him with the vision to become the Software Architecture & Design Lead for Robin RAMS. In the framework of the Fault Tree Analysis calculation module, he has developed a Direct Evaluation solution competing with Minimal Cut Sets methods. He is currently leading in the research activities in Predictive Maintenance within Robin, whose project has been awarded the Seal of Excellence as a high-quality project within the framework of Horizon Europe 2020.