Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a...
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Transcript of Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a...
![Page 1: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/1.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
UCD2...When all you have is a hammer...... every problem looks like a nail.
Registry, service description
Problems in the VO:
Resource discovery
Combine heterogeneous data
Answer=UCD ???
![Page 2: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/2.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
● UCD2 are motivated by practical needs.● It is not an attempt to build an absolute abstract vision of astronomy.
UCD should ensure interoperability between VO components:
● Do you have this quantity?● Can I compare this and that?
Standardized description of quantities, between:
● Fuzzyness of natural language● Specificity of data models
![Page 3: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/3.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Building UCD2
We need something working. Quick.
Conciliate 2 different views:● Bottom-up: describe what exists (VizieR, FITS headers...)● Top-down: global coherence, UCD3 in mind
Concept Property
Class
Instance
Idea of a galaxy Velocity
M31 120 km/s
UCD here
![Page 4: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/4.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Building UCD2
In UCD2: the primary word describes a property
Major problem: what is a property ? This can depend on the context. This can depend on the use case.phys.velocity
phys.velocity,srcstat.error,phys.velocity,src
![Page 5: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/5.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Use case
What is the price of a red apple ?
Query expressed in user's terms.
Analyse the query:
●We must find a value for a property: price●We have additional constraints:
●Fruit type must be an apple●Color must be red
![Page 6: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/6.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Use case
What is the price of a red apple ?
Query expressed in user's terms.
Find resource, and ask query:
SELECT item.price FROM resource WHERE item.fruit.type='apple' AND item.color='red'
UCD Not UCD
![Page 7: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/7.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Now, what do resources look like ? (resource discovery and querying)
Price Coloritem.price item.color0.19 green0.25 yellow0.39 red
Fruit Price Coloritem.fruit.typeitem.price item.colororange 0.50 orangegrape 0.75 violetapple 0.39 red... ... ...
item.fruit.type='apple'
apples
![Page 8: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/8.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Description of resource is critical...
●<PARAMETER> in VOTable : addition of a value to a <FIELD> (with associated UCD)● <GROUP>ing of fields, parameters
●No UCD for src.star, or src.galaxy, but src.class exists (concept/instances)●src.class='star' src.class='galaxy'●Need for a normalized vocabulary for objects types (thesaurus more than UCD)
star, late-type stars, early-type starsvariable stars, binary stars...galaxies, AGN, BL Lac, ...
![Page 9: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/9.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
●Need for useable description of parameters in tables.●UCD for instances of photometric bandpasses/filtersThis is not completely satisfying, but we
need it to compensate uncomplete descriptions !
Because we don't have the complete information:●<FIELD>: Column name= Vmag Unit = mag●Related <PARAMETER> :
ID,instr.bandpass= 'V filter'
We use:●Column name= Vmag●Unit = mag●UCD= phot.mag;em.opt.V
![Page 10: Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17 UCD2... When all you have is a hammer...... every problem looks like a nail. Registry,](https://reader038.fdocuments.us/reader038/viewer/2022110115/55149d00550346ea6e8b57df/html5/thumbnails/10.jpg)
Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
UCDFilters, bandpasse
s
UCDObjects types
Data Modelsutype
DALTranslation Layer
VOQL
VOTable
Registry
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Interoperability meeting S. Derriere, Strasbourg, 2003 October 16-17
Complex quantities
Complex = resulting from combination of basic properties. Maths +-/*...
Is it relevant to describe this with words ?
e.g. Color indices: B-V●should we define phot.colorIndex.B-V ? (but what about B-K, J-H, V-I, ...)●or do we allow something like (phot.mag;em.opt.B)-(phot.mag;em.opt.V)