Background to ASHiCS

SESAR WP-E: ASHiCS project 2011-2013


Project contact information: 
Dr. Rob Alexander (Project manager)
Dr. Kester Clegg
High Integrity Systems Engineering (SESAR WP-E ASHiCS)
Department of Computer Science
University of York
York YO10 5GH

Introduction and problem statement
Large systems of systems (SoS) such as ATM systems are challenging to model, as creating high-fidelity simulations for safety analysis can result in models that are themselves large and difficult to explore.  In order to explore these simulations effectively in the future, specifically designed algorithms may be able to discover hazards automatically and offer causal traces describing how those hazardous situations initially develop.  Our project investigates how we can use metaheuristic search to manipulate and configure ATM simulation models, so that a huge number of pathways and subsystem combinations can be explored without the need for manual intervention.

Predicting the consequences of making changes to part of a SoS can be difficult.  Emergent properties, such as self-organisation, manifest themselves above the level of individual subsystems making it hard to predict how the system will behave.  With pressure on safety-critical systems such as Air Traffic Management (ATM) to become larger and more complex, there is a growing risk that manual safety analysis methods will reach the limit of their capabilities before we have had chance to formulate alternative techniques.  In response to this, ASHiCS will work on a proof-of-concept approach that will enable future SESAR applications to automatically explore and safety check proposed changes to ATM scenarios. 

Project objectives and expected results
The project objectives are:
  • To provide the groundwork for a future, fully-automated hazard discovery process that can be used within a fast-time ATM simulation environment.
  • To demonstrate the potential for tool-based evidence to support the process of change management in complex systems of systems.
The project will produce, as outcomes: 
  • A systematic method for instrumenting risk within simulation models.

Approach / methodology
The output of these simulations will build up a picture of the critical system parameters in a given scenario, even when a direct casual link between system entities is not immediately obvious. The work will draw on in-house expertise at York for the design of the search algorithms to give advice on sophisticated techniques for understanding emergent phenomena and to provide in-depth SoS safety analysis.  The success of the project will be based on:
  • An analysis of how metaheuristic search could provide automated hazard discovery.  
  • Prototype software relevant to the aims of SESAR that demonstrates the approach in practice and embodies the algorithms.  
  • Reports that describe the methods and technologies used, with recommendations on how the approach could be scaled up for future SESAR applications.
The 23 month project is funded as part of the SESAR WP-E programme of long term research and development.  It will be carried out entirely by the University of York, in consultation with a panel of invited SESAR ATM domain experts and support from ISA Software Ltd.

Please contact Dr. Kester Clegg for more information on this project.