A Formal Basis for Safety Case Patterns

  • Ewen Denney
  • Ganesh Pai
Part of the Lecture Notes in Computer Science book series (LNCS, volume 8153)


By capturing common structures of successful arguments, safety case patterns provide an approach for reusing strategies for reasoning about safety. In the current state of the practice, patterns exist as descriptive specifications with informal semantics, which not only offer little opportunity for more sophisticated usage such as automated instantiation, composition and manipulation, but also impede standardization efforts and tool interoperability. To address these concerns, this paper gives (i) a formal definition for safety case patterns, clarifying both restrictions on the usage of multiplicity and well-founded recursion in structural abstraction, (ii) formal semantics to patterns, and (iii) a generic data model and algorithm for pattern instantiation. We illustrate our contributions by application to a new pattern, the requirements breakdown pattern, which builds upon our previous work.


Safety cases Safety case patterns Formal methods Automation 


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  1. 1.
    Alexander, R., Kelly, T., Kurd, Z., McDermid, J.: Safety Cases for Advanced Control Software: Safety Case Patterns. Final Report, NASA Contract FA8655-07-1-3025, Univ. of York (October 2007)Google Scholar
  2. 2.
    Denney, E., Habli, I., Pai, G.: Perspectives on Software Safety Case Development for Unmanned Aircraft. In: Proc. 42nd IEEE/IFIP Intl. Conf. Dep. Sys. and Networks (June 2012)Google Scholar
  3. 3.
    Denney, E., Pai, G.: A lightweight methodology for safety case assembly. In: Ortmeier, F., Lipaczewski, M. (eds.) SAFECOMP 2012. LNCS, vol. 7612, pp. 1–12. Springer, Heidelberg (2012)CrossRefGoogle Scholar
  4. 4.
    Denney, E., Pai, G., Pohl, J.: Automating the generation of heterogeneous aviation safety cases. Tech. Rep. NASA/CR-2011-215983, NASA Ames Research Center (August 2011)Google Scholar
  5. 5.
    Denney, E., Pai, G., Pohl, J.: AdvoCATE: An Assurance Case Automation Toolset. In: Ortmeier, F., Daniel, P. (eds.) SAFECOMP Workshops 2012. LNCS, vol. 7613, pp. 8–21. Springer, Heidelberg (2012)CrossRefGoogle Scholar
  6. 6.
    Denney, E., Pai, G., Pohl, J.: Heterogeneous aviation safety cases: Integrating the formal and the non-formal. In: 17th IEEE Intl. Conf. Engineering of Complex Computer Systems pp. 199–208 (July 2012)Google Scholar
  7. 7.
    Denney, E., Pai, G., Whiteside, I.: Hierarchical safety cases. In: Brat, G., Rungta, N., Venet, A. (eds.) NFM 2013. LNCS, vol. 7871, pp. 478–483. Springer, Heidelberg (2013)CrossRefGoogle Scholar
  8. 8.
    Goal Structuring Notation Working Group: GSN Community Standard Version 1 (November 2011), http://www.goalstructuringnotation.info/
  9. 9.
    Industrial Avionics Working Group: Modular Software Safety Case Process, Parts A and B: Process and Guidance. Tech. Rep. IAWG-AJT-301, Issue 2 (October 2007)Google Scholar
  10. 10.
    Kelly, T.: Arguing Safety: A Systematic Approach to Managing Safety Cases. Ph.D. thesis, Univ. of York (1998)Google Scholar
  11. 11.
    Kelly, T., McDermid, J.: Safety case construction and reuse using patterns. In: Daniel, P. (ed.) Safe Comp 1997, pp. 55–69 (1997)Google Scholar
  12. 12.
    Menon, C., Hawkins, R., McDermid, J.: Interim standard of best practice on software in the context of DS 00-56 Issue 4. SSEI Standard of Best Practice (Issue 1). Univ. of York (2009)Google Scholar
  13. 13.
    Object Management Group: Structured Assurance Case Metamodel (SACM) version 1.0. Formal/2013-02-01 (February 2013), http://www.omg.org/spec/SACM/
  14. 14.
    Sun, L., Kelly, T.: Elaborating the concept of evidence in Safety Cases. In: Proc. 21st Safety Critical Sys. Symp. (February 2013)Google Scholar
  15. 15.
    Weaver, R.: The Safety of Software – Constructing and Assuring Arguments. Ph.D. thesis, Dept. of Comp. Sci., Univ. of York (2003)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Ewen Denney
    • 1
  • Ganesh Pai
    • 1
  1. 1.SGT / NASA Ames Research CenterMoffett FieldUSA

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