DPN -- Dependability Priority Numbers
This addresses the need for systematic dependability evaluation and trade-off analysis in engineering systems, though it appears incremental as it builds on existing analysis methods.
The paper tackles the problem of combining quantitative dependability analysis with trade-off analysis for system design by proposing DPN (Dependability Priority Numbers), which compares actual dependability characteristics to target values and evaluates trade-offs, as demonstrated in a case study on a brake warning contact system.
This paper proposes a novel model-based approach to combine the quantitative dependability (safety, reliability, availability, maintainability and IT security) analysis and trade-off analysis. The proposed approach is called DPN (Dependability Priority Numbers) and allows the comparison of different actual dependability characteristics of a systems with its target values and evaluates them regarding trade-off analysis criteria. Therefore, the target values of system dependability characteristics are taken as requirements, while the actual value of a specific system design are provided by quantitative and qualitative dependability analysis (FHA, FMEA, FMEDA, of CFT-based FTA). The DPN approach evaluates the fulfillment of individual target requirements and perform trade-offs between analysis objectives. We present the workflow and meta-model of the DPN approach, and illustrate our approach using a case study on a brake warning contact system. Hence, we demonstrate how the model-based DPNs improve system dependability by selecting the project crucial dependable design alternatives or measures.