TY - GEN A1 - Höfig, Kai T1 - Analyzing the availability of a system N2 - An apparatus and method for analyzing availability of a system including subsystems each having at least one failure mode with a corresponding failure effect on the system are provided. The apparatus includes a degraded mode tree generation unit configured to automatically generate a degraded mode tree. The degraded mode tree includes at least one degraded mode element representing a degraded system state of the system that deviates from a normal operation state of the system based on a predetermined generic system meta model stored in a database including Failure Mode and Effects Analysis elements representing subsystems, failure modes, failure effects, and diagnostic measures. The apparatus also includes a processor configured to evaluate the generated degraded mode tree for calculation of the availability of the system. KW - System availability KW - Mode trees KW - Failure Mode Y1 - 2016 N1 - US Patent App. 15/048,644 ER - TY - GEN A1 - Höfig, Kai A1 - Zeller, Marc T1 - Automated Qualification of a Safety Critical System N2 - A method for automated qualification of a safety critical system including a plurality of components is provided. A functional safety behavior of each component is represented by an associated component fault tree element. The method includes automatically performing a failure port mapping of output failure modes to input failure modes of component fault tree elements based on a predetermined generic fault type data model stored in a database. KW - Automated qualification KW - Safety-critical systems KW - Fault trees Y1 - 2016 N1 - US Patent App. 14/644,119 ER - TY - GEN A1 - Höfig, Kai T1 - Automated Recertification of a Safety Critical System N2 - A method for automated recertification of a safety critical system with at least one altered functionality is provided. The method includes providing a failure propagation model of the safety critical system. The method also includes updating the failure propagation model of the safety critical system according to the at least one altered functionality using inner port dependency traces between inports and outports of a failure propagation model element representing the at least one altered functionality. The method includes calculating top events of the updated failure propagation model, and comparing the calculated top events with predetermined system requirements to recertify the safety critical system. KW - Automated recertification KW - Safety-critical systems Y1 - 2016 N1 - US Patent App. 14/586,818 ER - TY - CHAP A1 - Zeller, Marc A1 - Höfig, Kai T1 - INSiDER: Incorporation of system and safety analysis models using a dedicated reference model T2 - 2016 Annual Reliability and Maintainability Symposium (RAMS) N2 - In order to enable model-based, iterative design of safety-relevant systems, an efficient incorporation of safety and system engineering is a pressing need. Our approach interconnects system design and safety analysis models efficiently using a dedicated reference model. Since all information are available in a structured way, traceability between the model elements and consistency checks enable automated synchronization to guarantee that information within both kind of models are consistent during the development life-cycle. KW - Safety KW - CFT Y1 - 2016 SP - 1 EP - 6 ER - TY - CHAP A1 - Möhrle, Felix A1 - Zeller, Marc A1 - Höfig, Kai A1 - Rothfelder, Martin A1 - Liggesmeyer, Peter T1 - Automating compositional safety analysis using a failure type taxonomy for component fault trees T2 - Risk, Reliability and Safety: Innovating Theory and Practice: Proc. of ESREL N2 - Safety assurance is a major challenge in the design of today’s complex embedded systems and future Cyber-physical systems. Changes in a system’s architectural design invalidate former safety analyses and require a manual adaptation of related safety analysis models in order to restore consistency. In this work, we present an approach for automating the compositional assembly of Component Fault Trees by automatically generating mappings between their input and output failure modes. Therefore, we propose a taxonomy of failure types for annotating model elements and deriving a model of the failure propagation. This way, automatic and system-wide safety analyses can be executed and easily repeated after making modifications to the system’s architecture. We demonstrate the feasibility of our approach using an example ethylene vaporization unit from an industrial domain. KW - Compositional safety analysis KW - CFT Y1 - 2016 SP - 1380 EP - 1387 ER -