Transcript SKA and SKADS Costing The Future Paul Alexander Andrew Faulkner, Rosie Bolton

SKA and SKADS Costing
The Future
Paul Alexander
Andrew Faulkner, Rosie Bolton
2nd SKADS Workshop 10-11 October 2007
Paul Alexander
Costing The SKA
• Our aim is to deliver a final SKA
– No point in design without costing
– Concepts and designs have to fit within a realistic budget when
costed honestly
• At this stage of the project the priority is “cost modelling”
– Compare and contrast design options
– Identify cost scalings and cost drivers  modify design
• SKADS is playing a major role
– First fully costed design for the SKA – Benchmark Scenario
– Now coordinating the collaboration between SKADS, ISPO
team, AU and SA costing teams in a single SKA costing exercise
and tool – whole process overseen by ISPO
2nd SKADS Workshop 10-11 October 2007
Paul Alexander
Design and Costing
• SKADS is contributing very significantly to the SKA cost model
and tool and next generation tools and concepts
• SKADS deliverable is a fully costed design
– Excellent progress towards the main SKADS deliverable
– Design and costing and evolution of the SKADS Benchmark Scenario is a
continuing process and will continue until at least the end of SKADS
– Rosie Bolton will talk tomorrow about the details of the costing process in
SKADS
– I will discuss the process and the tools
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Paul Alexander
Completed Design and
Costing Exercise – 1
Initial D&C meeting
November 2006
Work on details of system blocks
D&C Review meeting
15 January 2007
Preparing written work
Initial Drafts
SKADS Benchmark Scenario
9 February
Consolidating paper
Final Draft
21 February
Approval of Paper
28 February
Publication of Paper
7 March 2007
Design and Costing
Paul Alexander1, Rosie Bolton1, Andrew Faulkner2, Steve Torchinsky3,
Arnold van Ardenne4, Peter Wilkinson2, Marco de Vos4, Laurens Bakker4,
Simon Garrington2, Georgina Harris2, Tim Ikin2, Mike Jones5, Dion Kant4,
Roshene McCool2 and Parbhu Patel4. On behalf of the SKADS team.
1
University of Cambridge, 2University of Manchester, 3Obs. de Paris, 4ASTRON,
University of Oxford
5
Abstract
The SKADS Benchmark Scenario is an overall SKA concept which aims to
meet as many as possible of the SKA requirements presented in the SKA
reference design. The key element of the system design is the use of aperture
array technology on all baselines below a frequency of 1 GHz which gives a
field of view of 250 square degrees in the key mid-frequency band. At higher
frequencies comparatively low-cost, small (6.1 m) antennas are proposed each
equipped with a single wide-band feed. The detailed design of high frequency
dishes and wide-band, single pixel feeds is likely under a highly
complementary US TDP programme and elsewhere. This Scenario is
presented in detail, concentrating in particular on the design of the key midfrequency aperture array and drawing on the work of other projects for
elements of the system outside of the expertise and scope of the SKADS
project. Detailed costing of the design suggests strongly that the Benchmark
Scenario is a practical and achievable implementation which delivers the
scientific performance for the SKA. The “worst case” cost is estimated to be
€1.91 Billion with an uncertainty of 9% costed for 2011. Further development of
the Benchmark Scenario will include detailed scientific and astronomical
evaluation and simulation together with cost optimisation and cost/performance
tradeoffs.
Revisit for SKA Design Specification Review
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Paul Alexander
Needed for stage 2
• Not addresses in SKA Memo 93
– Correlator design and costs
– Central processing hardware, model and costs
– Phased development of Benchmark Scenario costed
• Identify scalings throughout the design
• Better models and methods for:
– Dishes
– Accounting practices
– Uncertainty calculations
ISPO team
collaboration
– Optimisations and tradeoffs
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Paul Alexander
Timetable for Stage 2
Start second Design and costing exercise
12 September 2007
Update those areas not properly analysed in stage 1
ISPO preliminary SKA phase-1 and SKA specs
March 2008
SKADS input on costed design incorporating AAs
ISPO final SKA phase-1 and SKA specs
March 2009
Detailed SKADS input
Prepare for SKADS deliverable
2nd SKADS Workshop 10-11 October 2007
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Costing Methodology
• Ideal is to have a single approach to costing within the SKA
project
– Share expertise across the entire project
– Have a single tool we can use for comparative purposes
– Collaboration between SKADS, ISPO, AU and SA costing teams
– Two weeks work + meeting in Cambridge in June/July
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The approaches
• SKADS costing in SKA Memo 93 used a spreadsheet approach
– Good: exposed costs to everyone involved in the project
– Good: easy to use and modify by non-experts
– Good: mapped costing onto the design elements of the
telescope and kept the model intimately linked to the design
– Bad: difficult to simulate, do montecarlo uncertainty modelling
– Bad: consistency and error checking done by hand
– Bad: lacks flexibility and poor scaling of elements of the design
2nd SKADS Workshop 10-11 October 2007
Paul Alexander
The approaches
• ISPO modelling, SKA Memo 92
– Good: simulation environment with montecarlo modelling
– Good: scaling and model exploration
– Good: consistency and error checking
– Bad: difficult for non experts to alter
– Bad: assumptions not easily exposed to the user – the tool can
be dangerous if the underlying model is wrong or not
appreciated by the users
– Bad: difficult to incorporate a real design or consider effects of
design changes
• SA costing for MeerKAT
– Good: used same original code base as ISPO
– Good: excellent tools to visualise outputs
– Bad: see ISPO
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Structure of a new tool
SKA
realisation
Design Block
Design Block
Design Block
Component
Design Block
Design Block
Component
Component
2nd SKADS Workshop 10-11 October 2007
Component
Paul Alexander
Structure of the new tool
• Adopt the SKADS high-level view
– System consisting of Design Blocks we combine together to form a realisation of
the telescope
– Design blocks use costed components and/or cost models which are determined
by domain experts
– The costing process involves everyone
• Use a modified ISPO code base for the implementation + new UI
– Python code (initially) implements the specifications / design of each design block
– Standard software tools provided to ensure consistency, error checking,
uncertainty modelling
– GUI enables non-experts to browse, modify and develop components and design
blocks (some python code needed)
• Build in the MeerKAT approach to visualisation
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Design Block
reporting and design structure
Cost modelling code
(python or …)
Library of DBs
and components
(xml format)
GUI interface
2nd SKADS Workshop 10-11 October 2007
Paul Alexander
Structure of the new tool
2nd SKADS Workshop 10-11 October 2007
Paul Alexander
Example Model: Aperture
Array
2nd SKADS Workshop 10-11 October 2007
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GUI Snapshot
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The Repository
• Develop libraries of components and design blocks in a
repository
• Domain experts review, extend and modify these
• Expect an SKA wide repository and also repositories
local to other projects one at least
• Individuals can have their own library or modify existing
system realisations, design blocks and components
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Using the Model
• Astronomer
– Use an existing design of the SKA and investigate cost and
performance tradeoffs within the design, output performance
information/statistics
• System designer or expert radio astronomer
– Construct SKA realisations (systems) out of existing design
blocks and components
• Engineer
– Develop and review design blocks and components
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Timeline – Best Efforts
• End September
– Include basic AA description into costing tool
• Mid October
– GUI to browse component library
– Underlying change to system architecture
• Mid November
– GUI to browse / modify design block library
• January/February 2008
– First release of an integrated tool
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Conclusions
• Initial design and costing has been a very good first step towards our
final deliverable
• We have learnt a great deal about feasible and affordable designs
• SKADS coordinating intercontinental effort to deliver the SKA costing
tool
• Work to date crucial in establishing AA technology as a core technology
for all SKA options
2nd SKADS Workshop 10-11 October 2007
Paul Alexander