2008-06-26Gerard Lemson Theory in the VO and the SimDB specification Euro-VO DCA workshop Garching, June 26, 2008 Feedback questionnaire

2008-06-26 Gerard Lemson

Theory in the VOand the SimDB specification

Euro-VO DCA workshopGarching, June 26, 2008

Feedback questionnaire


Overview Theory in the VO

Definition Motivation Issues

Standardisation for theory Existing standards Theory interest group: SimDB and SimDAP Prototype implementations


What theory? Simulation resultss

raw, “Level-0” data Post-processing, Level-1 products

halo catalogues theoretical spectra ...

Synthetic observations (Level 2) virtual telescope

Analysis (Level 3?) correlation functions power spectra ...

Services related to these

This talk, focus on LARGE simulations and post-processing products 3+1D, spatial/temporal “micro-physics” simulations under discussion, sometimes already

supported.


Detailed observations

electron density

gas pressuregas temperature

Courtesy Alexis Finoguenov, Ulrich Briel, Peter Schuecker, (MPE)


Require detailed models

Courtesy Volker Springel


Observations in the VO Most VO efforts concentrate on observational

data sets simple observables: photons detected at a certain

time from a certain area on the sky long history of archiving pre-existing standards (FITS) valuable over long time (digitising >80 yr old

plates) Standards observationally biased

common sky: cone search, SIAP, region common objects: XMatch data models: characterisation of sky/time/energy,

STC


Theory in the VO: issues Simulations not so simple

Complex observables, non-standard No standardisation on data formats or metadata Archiving ad hoc, for local use

Moore’s law makes useful lifetime relatively short: few years later can do better

Current IVOA standards somewhat irrelevant No common sky No common objects New data models required for content, physics,

code


“Moore’s law” for N-body simulations

Courtesy Simon White

Millennium Run

Mare Nostrum


Historical simulations

Toomre & Toomre, 1972

Di Matteo, Springel and Hernquist, 2005

Volker Springel


Theory in the VO: issues Simulations not so simple

Complex observables, non-standard No standardisation on data formats or metadata Archiving ad hoc, for local use

Moore’s law makes useful lifetime relatively short: few years later can do better

Current IVOA standards somewhat irrelevant No common sky No common objects New data models required for content, physics,

code


So why bother? Simulations are interesting:

For many cases only way to see processes in action

Complex observations require sophisticated models for interpretation

Bridging gap in specialisations: not everyone has required expertise to create simulations, though they can analyse them.

Many use cases do not require the latest/greatest exposure time calculator survey design


DAL standards Similarity of

products SSAP

theory spectra SCS-like

mock catalogues SIAP-like

visualisation services


Other Registry

Allows any web service ADQL + TAP

theory SkyNode (Rick Wagner) Millennium Run (see later today)

Applications VisIVO (see later today)

Semantics theory UCDs Vocabularies/ontologies for astronomical

objects, physical processes, ...


SimDB and SimDAP Effort of IVOA theory interest group Originally attempt at S*AP protocol for

simulations (SNAP) queryData getData

DAL v2: based on data model. queryData in terms of elements in DM

getData special attention large datasets no uniform formats see SimDAP presentation (Claudio Gheller)


SimDB: Simulation Database Supports discovery of interesting

simulation results. and links to (SimDAP)services for

accessing them Rich data model describing simulations

and post-processing products Focused on 3+1D simulations

but easily extended


Common questions What was simulated?

LSS, galaxy merger, rings of Saturn What physics was included?

gravity only, hydrodynamics, chemistry How is the world represented?

N bodies, adaptive mesh, spherically symmetric 1D

What properties are calculated? position, velocity, mass, temperature, density,

chemical abundances How do I get access? etc.


SimDB: Data model (in progress)

http://code.google.com/p/volute/source/browse/trunk/projects/theory/snapdm/input/SimDB_DM.xml


File


Storage


Results of Experiments


Experiments


Protocol


Parameters


Target


Web service


SimDB data model


Complex? Registry data

model

Spectrum Data Model

STC SDSS SkyServer

etc.


Representations (Generated)* XML Schemas

Protocol: PDR code (courtesy Franck LePetit + Laurent Bourges)

Simulation: Millennium Run Ideally generated from simulation and post-

processing pipe-lines Relational Database Schema Java code HTML

* http://code.google.com/p/volute/wiki/TheoryHome

http://code.google.com/p/volute/source/browse/trunk/projects/theory/snapdm/output/schema/

http://code.google.com/p/volute/wiki/TheoryHome


XML fragments (PDR protocol)








RDB views (ADQL/TAP interface)


RDB tables (generated)








SimDB: Implementation Complex data model requires more

advanced support Simple HTTP requests insufficient Browsing or full query language needed

More registry than S*AP queryData a few central sites (France, Germany,

Italy, USA) with advanced access methods


(Laurent Bourges)


Access Services (in progress) ADQL+TAP

relational mapping global-as-view wrapping

“REST” XML documents GET and PUT (and DELETE ?)

OAI ala Resource Registry harvesting

Web Browsing (example) Fully generated support possible (in

progress)


Prototypes CNRS

GalMER ITVO

Trieste: http://wwwas.oats.inaf.it/IA2/ITVO Catania: http://itvo.oact.inaf.it

Under development SimCat (UCSD) PDR/SimDB (Paris) Horizon/GalICS (Lyon) GAVO (hydro simulations)


Main message SimDB/SimDAP in progress Participate in the IVOA theory interest

group If you have a “theory service”

whether standard or not: wrap it deploy it register it


Thank you.

Thanks toUgo BeccianiLaurent BourgesIgor ChillingarianClaudio GhellerNorman GrayFranck LePetitMireille LouysPatrizia ManzatoRick WagnerHervé Wozniak

Documents

2008-06-26Gerard Lemson Theory in the VO and the SimDB specification Euro-VO DCA workshop Garching, June 26, 2008 Feedback questionnaire