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Engineering Emergence - at Nano-scales

Engineering Emergence - at Nano-scales. Fiona Polack With acknowledgements to the TUNA project team, and Tim Kelly’s HISE argumentation group. Gosper’s glider gun : emits glider stream. … complex emergent behaviour. gliders : patterns that moves constantly across the grid

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Engineering Emergence - at Nano-scales

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  1. Engineering Emergence - at Nano-scales Fiona Polack With acknowledgements to the TUNA project team, and Tim Kelly’s HISE argumentation group

  2. Gosper’s glider gun : emits glider stream … complex emergent behaviour • gliders: patterns that moves constantly across the grid • after 4 generations the original pattern is reproduced one site further right and one site further down http://www.math.com/students/wonders/life/life.html http://www.cogs.susx.ac.uk/users/andywu/gallery/ddlab_gallery.html http://en.wikipedia.org/wiki/Conway's_Game_of_Life

  3. Emergence – a different example! At the nano-scale: particles doing their thing (Cannot determine the emergent goal from this …)

  4. Emergence If there are enough particles, features are observed at a macro-scale Particles are water molecules – emergent effect is flowing water Wharfe, Burnsall, March 2006

  5. Emergence Actual effect dependent on environment: riverbed depth (vol. of water) gradient etc Moselle, June 2006

  6. Emergence Actual effect dependent on environment: riverbed depth (vol. of water) gradient etc Effect of variation among particles is minimal Troller’s Gill,, March 2006

  7. Using nano-scale emergence • Proposals for nanite assemblers • Artificial platelets; repair and maintenance etc • Risks: • Inadequately-modelled environment • Replication of elements causing dangerous mutation • Engineering problems: • Element and system models/languages are different • Emergent properties do not refine

  8. Engineering emergent systems • Nanite assemblers are critical systems • Must be reliable • operator control or override is not possible • Must avoid damage, under operation or failure • Plan for an engineering framework • Exploit existing best practice in critical systems • Motivate contents by need to assuredependability • Three contributions so far…

  9. Macro language Nano language element system specification specification mapping specification element system in environment in environment system combined language Contribution 1: an architecture • Map between macro and nano models (languages) via environment:

  10. mappedSpec model mappedImpltn model Integration Environment rule migration: rules for primitive behaviours(movement, aggregation, dispersion, …); plus means to combine rules Contribution 1: an architecture Specification of emergent system Implementation of individual agents

  11. Examples Moving shapes Cell sites on grid Run CA on grid GoL gliders CA GoL rules Platelet aggregation Platelets in static vessel Blood flow in vessel Mobile platelet behaviour Implementation of nanite platelets

  12. Contribution 2: assurance-driven engineering • Emergent systems are critical systems • Parallel development goals: • Construct an emergent (eg nanite) system • Construct a dependability argument • Look to York research on dependability of macro-scale systems of systems (SoS) • Command and control systems • Kelly, Alexander, Hall-May, Despotou and others

  13. State of the Art (Kelly et al,York HISE group) • Dependability arguments forSoS • Safety, security, reliability, ... & their interactions • Cross-system arguments & policies • Evidence-based software engineering • Development driven by need for evidence • Argumentation also used to justify techniques • Argumentstructures; argument management • Derived for safety certification

  14. Argument management (HISE) • Goal Structuring Notation and argument management • Modular, reusable arguments and patterns context goal1 • Structured presentation of argument and of evidence • Goal decomposition; cross-goal analysis • Explicit context and assertion strategy goal2 goal3 solution

  15. A structure for assurance argument Constructed using GSN Visio plug-in

  16. Related - Contribution 3:adapting macro SoS to nano scale • Macro SoS characteristics • Overall goals, shared by all components • Individual component goals • Multiple heterogeneous components with individual capabilities & some autonomy • Spatial distribution & mobility of components • Components need to collaborate to achieve overall goals • Communication by ad hoc networks [Alexander, Hall-May & Kelly 04]

  17. Adapting system of systems to nano-scale • No humans involved • No sense of buy-in to goals by elements • Free will replaced by probabilistic features of elements & environment • Policies, operational guidance etc irrelevant • No imaginative solutions to unforeseen scenarios • Probabilitistic behaviour rather than autonomy • Other SoS features are quite similar

  18. DISCUSS

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