Gerard Lemson, IVOA DM 28/5/2004

Unified domain model for Astronomy Much maligned and misunderstood (anonymous) with Pat Dowler and Tony Banday (MPA) Background/goals Methodology (analysis model) Language (UML) Content Binding (XML Schema, Java, …) Usage (views)

Gerard Lemson, IVOA DM 28/5/2004 Goal Find place for (seemingly) disparate sub-areas in DM: quantity-observation-simulation- phenomenology(-proposal ?) Background: analysis phase in software design Understand the universe of discourse (problem domain) Benefits Patterns for design and implementation models. Formalize comparability Domain model as Esperanto Domain model == ontology ?

Gerard Lemson, IVOA DM 28/5/2004

Methodology Object oriented analysis: –a method of analysis in which requirements are examined from the perspective of the classes and objects found in the vocabulary of the problem domain. (Booch) Universe of Discourse –.. the world(or universe) that we are interested in talking (or discoursing) about (Halpin) List concepts and relations Translate into formal language (UML) –Normalized –Explicit –Patterns

Gerard Lemson, IVOA DM 28/5/2004 UML

Gerard Lemson, IVOA DM 28/5/2004 Universe of Discourse for VO We want to talk/discourse about the work that astronomers, astrophysicists and support scientists do and the results they have obtained We want to do this in a scientifically rigorous manner

Gerard Lemson, IVOA DM 28/5/2004 Concepts experiment, observation, simulation, result, protocol, objective (observable, goal), variable (dependent, independent), measurement, value, quantity, category, uncertainty, confidence, error, classification, identification, phenomenon, property, subject (body, substance, space,...), unit, reference system, representation, standard, physical artifact, file, table

Gerard Lemson, IVOA DM 28/5/2004 Analysis pattern: Observation and Measurement Martin Fowler 1997, Analysis Patterns, Addisson Wesley

Gerard Lemson, IVOA DM 28/5/2004 SI A quantity in the general sense is a property ascribed to phenomena, bodies, or substances that can be quantified for, or assigned to, a particular phenomenon, body, or substance. Examples are mass and electric charge. A quantity in the particular sense is a quantifiable or assignable property ascribed to a particular phenomenon, body, or substance. Examples are the mass of the moon and the electric charge of the proton. A physical quantity is a quantity that can be used in the mathematical equations of science and technology. A unit is a particular physical quantity, defined and adopted by convention, with which other particular quantities of the same kind are compared to express their value. The value of a physical quantity is the quantitative expression of a particular physical quantity as the product of a number and a unit, the number being its numerical value. Thus, the numerical value of a particular physical quantity depends on the unit in which it is expressed.

Gerard Lemson, IVOA DM 28/5/2004

Binding XML Schema –Presentation during registry teleconPresentation during registry telecon Formalize bindings as XSLT working on XMI representation of UML diagrams Example: –Java + hibernate mapping files + AXIS Java2WSDL == metadata repository

Gerard Lemson, IVOA DM 28/5/2004 Usage Complex model Simplify using view concept Example from RDB ( to Francois Bonnarel, link)link XSLT for translation between domain XSD and application-specific derived schemas.

Gerard Lemson, IVOA DM 28/5/2004 CREATE VIEW SEXTRACTOR_GALAXIES AS SELECT S.RA AS _RAJ2000, S.DEC AS _DECJ2000, -2.5 * LOG(S.FLUX) AS M_APP, S.CLASSIFICATION, I.STORAGE_URL AS IMAGE FROM SOURCE S, SOURCE_CATALOGUE SC, IMAGE I, SOURCE_EXTRACTOR AS SE WHERE S.CLASS = GALAXY AND S.FLUX < 15 AND S.CATALOGUE_ID = SC.ID AND IMAGE.ID = SC.IMAGE_ID AND SC.EXTRACTED_WITH = SOURCE_EXTRACTOR.ID AND SE.IDENTIFIER = SExtractor