CSC 379:Week 5, Group 5: Difference between revisions
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"Accident models based on systems theory consider accidents as arising from the interactions among system components and usually do not specify single causal variables or factors" | "Accident models based on systems theory consider accidents as arising from the interactions among system components and usually do not specify single causal variables or factors" | ||
"In the simpler systems of the past, where all the interactions between components could be predicted and handled, component failure was the primary cause of accidents. In today’s complex systems, made possible by the use of software, this is no longer the case." | |||
==Why was the Milstar satellite damaged although the components of the Inertial Navigation Unit (INU) operated correctly with respect to the instructions, including constraints, and data provided? Why would use of the STAMP model more thoroughly prevent problems such as those that occurred with the INU compared to traditional accident reporting?== | ==Why was the Milstar satellite damaged although the components of the Inertial Navigation Unit (INU) operated correctly with respect to the instructions, including constraints, and data provided? Why would use of the STAMP model more thoroughly prevent problems such as those that occurred with the INU compared to traditional accident reporting?== | ||
Revision as of 22:48, 2 August 2007
Software Safety: Accident Models - Systems Theory vs. Chain of Events
Skim through the following paper (focus on sections 1, 2.3, and 3, skip figures and tables) entitled "A Systems-Theoretic Approach to Safety in Software-Intensive Systems" by Nancy G. Leveson, a Professor of Aeronautics and Astronautics at MIT, then answer the following questions:
What are some shortcomings of traditional methods of accident reporting when applied to complex systems like software systems?
- Blame - "reports stopped after assigning blame—usually to the operators who interacted with the software—and never got to the root of why the accident occurred"
"in dealing with software in safety-critical systems is the result of inappropriately attempting to extend the techniques that were successful in simpler, electromechanical systems and were based on models of accident causation that no longer apply"
How does the STAMP model improve accident prevention efforts? Explain some general concepts of the model.
"Systems theory allows more complex relationships between events to be considered"
"Accident models based on systems theory consider accidents as arising from the interactions among system components and usually do not specify single causal variables or factors"
"In the simpler systems of the past, where all the interactions between components could be predicted and handled, component failure was the primary cause of accidents. In today’s complex systems, made possible by the use of software, this is no longer the case."
What are some appropriate applications of the STAMP model (both current and past)? Explain.
What are some ethical concerns of assigning blame for accidents?
The majority of the content you need to form an informed response to the above questions is included in the paper. Bring in outside resources and topics discussed in class lectures as appropriate to support your response.