Transcript Safety Justification of Artificial Neural Networks in

Develop a Safety Assurance
approach for Complex Systems
(Problem Definition)
Chris Leong
HISE Group
Supervisors: Tim Kelly, Rob Alexander
Giving a Presentation - Nov 14
Problem Definition
• With more and more independent entities (systems and platforms)
dynamically networking as a complex system to achieve a common
purpose (e.g. operation and training),
How safe is considered
safe enough for such
complex system?
How can simulation help
to make safety
assessment of such
complex system more
effective and efficient?
Is the current way of
doing hazard and risk
analysis and safety
assessment sufficient to
analyse such complex
system?
How do we consider the
unique characteristics
(e.g. adaptive and
emergent) of such
complex system as part
of safety assessment?
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Key Concepts
Develop a Safety Assurance
approach for Complex Systems
• What is Safety Assurance?
• Which description of Complex System best
describes the problem space?
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Safety Assurance
HA: Hazard Analysis
• Identifies potential hazards
and safety risks of the system
PSA: Preliminary Safety
Assessment
• Performs safety analyses as the
system is being developed to
suggest design and architectural
choices to meet safety goals
HA
PSA
SSA
[Bozzano10]
General safety assessment workflow
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SA: Safety Assessment
• Verifies compliance of the
system architecture with the
safety requirements
Complex System
Dynamic of Complex System
[Yam97]
A complex system is a system formed out of
many components whose behaviour is emergent,
that is, the behaviour of the system cannot be
simply inferred from the behaviour of its
components. The amount of information
necessary to describe the behaviour of such a
system is a measure of its complexity.
Cyber-Physical Systems (CPS) [Shi11]
systems that integrate the dynamics of the
physical processes with those of the
software and communication, providing
abstraction and modelling, design, and
analysis techniques for the integrated world
Open Adaptive Systems (OAS) [Trapp13]
systems that dynamically connect to each
other (openness) and adapt to a changing
context at runtime (adaptive)
System-of-Systems (SoS) [Kazman13]
Is a set of systems that are cooperating
while simultaneously working as
independent entities
….
Properties
System-ofSystems
Open
Adaptive
Systems
Independence
Yes
Geographical distributed
Yes
Emergent behaviour
Yes
Yes
Evolutionary development
Yes
Yes
Interface interactions
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Cyber
Physical
Systems
Yes
Yes
Yes
Summary
• Safety assurance: Leverage on the different
phases under the safety engineering practices
to minimize the risks of operational hazards
(e.g. HRA, PSA, SSSA, certification, awareness).
• Complex Systems: Intend is not to present a
unified definition but to gain awareness of the
unique characteristics compared to monolithic
systems (e.g. independence, emergent
behaviour, evolutionary)
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