philosophical question about VOEvent

[Matthew Graham]

Hi,

So let's see what the spec actually says: "The <What> and <Why> elements work together to characterize the nature of a VOEvent. That is: <What> was factually measured or observed to occur, versus <Why> in terms of its hypothesized underlying cause or causes". And in the <Why> section, the <Inference> element has an attribute "probabililty" which "is an estimate of the likelihood of the <Inference> accurately describing the event in question. It is expressed as a floating point number bounded between 0.0 and 1.0 (inclusive)." 

So use "probability" in <Why> to report your "percentage measure of fit" and put the proper details of how likelihood was "factually measured" in the <What> section.

	Cheers,

	Matthew



On Mar 19, 2010, at 8:53 AM, Roy Williams wrote:

> I am running into a difficulty with the VOEvent model of reporting a transient. The problem is that the schema is ostensibly divided into "philosophical" sections: Who, What, Wherewhen, Why etc, but there are also "structural" sections, where we ask who is making the data model. For example, the Wherewhen section has a data model that the IVOA has defined, to make positions and time quite rigorous; but the What section has a data model defined by the author of the event, who invents and defines parameters that have meaning in relation to a specific instrument or project. From a structural point of view, it seems that What is where author-defined data model goes, and the other sections have an IVOA-defined data model.
> 
> So here is the question. Suppose events from a certain stream come with classification, and the author of those events wishes to express the quality of the classification as some sort of goodness-of-fit statistic on the classification, let's call it X. On the "philosophical" interpretation of VOEvent, X should be part of the Why section because it is "hypothesized underlying cause or effect" (quoting VOEvent spec), but unfortuantely the Why section has IVOA-defined syntax, and so there is no place in its data model for X (it only allows a percentage measure of fit). Structurally, X goes most easily into the What section, because the author can describe and define its meaning there.
> 
> Should we try to put X into the Why section of the VOEvent (how?), or simply put it in the What section, claiming that X is a measurement?
> 
> Your opinions welcome!
> Roy
> 
> -- 
> 
> California Institute of Technology
> 626 395 3670
> 

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