SAHARA - A Structured Approach for Hazard Analysis and Risk Assessments

  • In this thesis, an approach is presented that turns the currently unstructured process of automotive hazard analysis and risk assessments (HRA), which relies on creativity techniques, into a structured, model-based approach that makes the HRA results less dependent on experts' experience, more consistent, and gives them higher quality. The challenge can be subdivided into two steps. The first step is to improve the HRA as it is performed in current practice. The second step is to go beyond the current practice and consider not only single service failures as relevant hazards, but also multiple service failures. For the first step, the most important aspect is to formalize the operational situation of the system and to determine its likelihood. Current approaches use natural-language textual descriptions, which makes it hard to ensure consistency and increase efficiency through reuse. Furthermore, due to ambiguity in natural language, it is difficult to ensure consistent likelihood estimates for situations. The main aspect of the second step is that considering multiple service failures as hazards implies that one needs to analyze an exponential number of hazards. Due to the fact that hazard assessments are currently done purely manually, considering multiple service failures is not possible. The only way to approach this challenge is to formalize the HRA and make extensive use of automation support. In SAHARA we handle these challenges by first introducing a model-based representation of an HRA with GOBI. Based on this, we formalized the representation of operational situations and their likelihood assessment in OASIS and HEAT, respectively. We show that more consistent situation assessments are possible and that situations (including their likelihood) can be efficiently reused. The second aspect, coping with multiple service failures, is addressed in ARID. We show that using our tool-supported HRA approach, 100% coverage of all possible hazards (including multiple service failures) can be achieved by relying on very limited manual effort. We furthermore show that not considering multiple service failures results in insufficient safety goals.

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Author:Sören Kemmann
URN:urn:nbn:de:hbz:386-kluedo-40270
Advisor:Peter Liggesmeyer
Document Type:Doctoral Thesis
Language of publication:English
Date of Publication (online):2015/03/17
Year of first Publication:2015
Publishing Institution:Technische Universität Kaiserslautern
Granting Institution:Technische Universität Kaiserslautern
Acceptance Date of the Thesis:2015/02/27
Date of the Publication (Server):2015/03/18
Tag:Funktionale Sicherheit; Gefahren- und Risikoanalyse; Risikobewertung
Functional Safety; Hazard Analysis; ISO 26262; Risk Assessment; SAHARA
Page Number:IX, 211
Faculties / Organisational entities:Kaiserslautern - Fachbereich Informatik
CCS-Classification (computer science):D. Software
DDC-Cassification:0 Allgemeines, Informatik, Informationswissenschaft / 004 Informatik
Licence (German):Standard gemäß KLUEDO-Leitlinien vom 13.02.2015