RE: [obix] Proposed "Relationship" feature for oBIX

That kind of sounds like CORBA tried to do with the relationship service.

I think the REST and web way of doing that is to just use URIs to cross reference other oBIX documents. The question really boils down to if the references should be typed, or enough semantics are implied simply by the name attribute of the ref element. I kind of prefer to try loose typing first which lends itself to plain text search and only add typing when a very clear use case emerges.

Regarding the map location, that would more likely be an object you would read/write (or GET/PUT) than an operation you would invoke. Location gets into the BIM issues and how you model “spaces” and “systems”. Which would be very nice to standardize (but a lot of work ahead of us).

From: Considine, Toby (Technology Services) [mailto:Toby.Considine@unc.edu]
Sent: Saturday, June 23, 2007 4:55 PM
To: obix@lists.oasis-open.org
Subject: [obix] Proposed "Relationship" feature for oBIX

Proposed “Relationship” feature for oBIX

Numerous conversations in the last month have caused me to focus on the relationship between systems. Inside a single control system, perhaps all components are part of a single system, but as we reach out beyond a single system, and define interactions across domains, we will want a means to put a system in context.

The relationship types I see, quickly, are

- Support – with a URI to the system it supports.

- Is Supported by – with a URI to the system it is supported by.

- Is a component of - with a URI to the system it is a component of.

- Is comprised of – with a list of URIs to its components.

- Is allied with – with URIs to all the other systems this works with, but for which no hierarchy is apparent

Note: in a world with heterogeneity, in which we cannot assume that all systems are on the same revision, or have the same capabilities, there should be no presumption that the system I point to with a URI has a reciprocal URI pointing back at me.

If the URL points to a BIM server, this gets us to “HVAC system for the 3^rd floor (and a pointer to the URI for the model of the 3^rd floor). There will have to be methods to set and remove these relationships as well.

Referring to previous committee work, this would also serve as a general case of to two of the methods requested by the power systems sub-committee:

- Service: obixps.set_location_map(location descriptions)
Description: sets the mapping of locations to specific meters.

Example:
Obixps.set_location_map(…,Murry_Hall.Floor1=subnetwork3_meter12, …)
This command maps the first floor of Murry Hall to a specific meter.

"It is the theory that decides what can be observed." - Albert Einstein

Toby Considine

Chair, OASIS oBIX TC
Facilities Technology Office
University of North Carolina
Chapel Hill, NC

Email: Toby.Considine@ unc.edu
Phone: (919)962-9073

http://www.oasis-open.org

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