Embed Size (px)
Citation preview
BuildingupaTimeSeries DataModel
M.Louys,F.Bonnarel,L.Michel,A.Nebot,M.CresitelloDittmar,B.Cecconni,T.Boch,S.Derrière,GillesLandais
• Timeseriesisconsideredinalargesenseasacollectionofdatasamples,takenalongasequenceoftimestamps.
• F=f(t),withFbeing– asimplevalueforameasure,– Onestructuredmeasurewithvalue,error,precision,etc.–Multiplevalues(e.g.multi-wavelength)– Adatasetitself,e.g.thedataproductresultingofanobservation:spectrum,image,cube,etc .
• Fis adataset,observed inonegoorcompiled from variousobservations
Which TimeDomainDatatocover?
• Fhasasetofmeasures along some observed physical axes– Position,spectralband,polarimetry,– Observablesvarying with time:velocity,flux,mag,etc .– RichdescriptionofTimeaxisproperties
• Search forTimedomain data:–When arethetimestamps taken andhow?–Which observablequantities (measures) areavailable foratimeseries dataset?
–Which axestogether with their coordinate system?
Minimalmetadata needed
Various combinations usecases
Ultracam timeseries
0
0,5
1
1,5
He
0
0,5
1
1,5
0,5 1 1,5 2 2,5 3 3,5 4 4,5
u'
0
0,5
1
1,5
2
r'
Phase
norm
aliz
ed c
ount
rate
Various combinations usecases
MultibandFluxmeasures
IVOAmeeting,VictoriaMay2018,TimeDomain&DM,Mireille Louys
Coord/Measure
T1 T2 T3 T4 T5 T6 T7 T8 Timerange Mintimeperiod T-xel
magB + + + 3
Err_magB + + + 3
magV * * * * T8-T2 Min(tj+1-tj) 4
Err_magV * * * * 4
magU ^ ^ ^ ^ ^ T7 –T4 5
Err_magU ^ ^ ^ ^ ^ 5
Measures +datasets
Progenitor imageLocalisationmap
DataModelReuse from theIVOA
• ATimeseries is– adataset à reuse ObsDataset from DatasetMetadata DM– Amultiaxisdatasetà reuse SparseCubeCube DM– AcollectionofpointsofmultipledimensionsCubeNDPoint– TheprincipalCubeDataAxis is TimeAxis– Its properties can be summarized with Characterization DM – Measures/Observations depend ontimesamples– Simplemeasurement à reuse CoordMeasure asinSTCv2.0 DM– Structured measures asdataproducts à ObsDataset element from
DatasetMetadata DM
– Bundleofmeasurements onasimilar physical axisà To be modelled
Discoveryà Characterisation DM
Dataselection :Simplemeasure
Multiple Measurements
Dataselection :associated dataproducts
Howtohandle multiplemeasures
• Simplelightcurve 1TimeAxis,1Fluxaxis• Multiwavelength lightcurve–MultipleDataAxis asFluxaxis=f(λ)
• Heterogeneous TS– Lightcurvewith associated images(orspectra?)
• TSofdatasets– CubeTS,e.g.MUSEseries ofhyperspectral cubes
IVOAmeeting,VictoriaMay2018,TimeDomain&DM,Mireille Louys
Howtobind with STC/meas andcoos
• We identify thebasicphysical measures inTSDM• Howtodescribe them inSTC
Measures ,CoordMeasure,etc .
• Howtobind totheCoordinate Frames
• Describe allkinds ofObservables– Generic physical measure with UCDTag
IVOAmeeting,VictoriaMay2018,TimeDomain&DM,MireilleLouys
Grouped bycolorGrouped bysourceIfseveral visits,etc.
instancenb
Multiplicity case:multiband /heterogeneous details level
IVOAmeeting,VictoriaMay2018,TimeDomain&DM,Mireille Louys
t1
• magB• errorMagB
t2
• magB• errormagB• magU• errormagU
t3
• magV• errormagV• magU• errormagU
t4
• magB• errorMagB
t5
• magB• errormagB• magU• errormagU
t6
• magV• errormagV• magU• errormagU
Modeling Status
• Coded intheModelioUMLmodeler3.6• VODMLImportofCubeDMandSTCDM• Todo–Re-use CharDM andEPN-Core DMforcompleting theTimeAxis description–Resolve howtorepresent multiplicityofobservablesatatimestamp–Generation oftheVO-DMLxml descriptionforthis model–Generation ofthehtmldocumentationviaVO-DMLtools
• Exploremoresciencecases
IVOAmeeting,VictoriaMay2018,TimeDomain&DM,Mireille Louys
Lessons learned
• Therearealotofconceptsalready existing• There-use ofclassesfrom different models is moretricky thanexpected–Modelcomplexity :many levels ofabstractioninSTC–Modeling tool
• Importing themodels inModelio is notstraightforward– Importofxmi works– Cannot see theclassesinModelio
• Moretoexperience atVODMLHackaton
