Notes on semantics and models

[William Cox <wtcox@CoxSoftwareArchitects.com>]

These are a few notes on semantic and modeling issues. This is background for agenda item 3 today. Specific work items are discussed below.

Agenda:
3. Discussion on information models, exactly-one and implicit relationships, and definitions of programs/terms and conditions. (Bill Cox) Please have available the following documents:
(a) CEC Report PDF http://www.oasis-open.org/committees/download.php/33260/cec-500-2009-063.pdf
(b) Committee Draft 01 (PDF in http://www.oasis-open.org/committees/download.php/33627/energyinterop-1.0-spec-wd-01.zip)

I got started thinking about the contractual/terms and conditions model for "programs", which are often reflected in tariffs. Since tariffs are a formalization of agreements, and aggregator/facility agreements are not always reflected in tariffs, without loss of generality (I hope) I'll use the term "contracts".

Notes with line numbers are to the Committee Draft 01 PDF; notes with page numbers are to the CEC PDF linked above.

(a) The table on lines 393-400 has no description of programs; in the CEC document they're in Appendix D (APD-1 et seq, page 149 of the PDF). The descriptions, or a more general mechanism, will be needed so CD02 holds together better.  Evan's email (http://lists.oasis-open.org/archives/energyinterop/200908/msg00030.html) on August 13 points this out.

The key issue to me is "how do you define a program"; just as there is a program reference/name in the schemas in CD01, there is a desciption and namespace (NOT XML namespace) issue for the names. Should names be globally unique? That requires a registry and more. Should they be locally unique? More than one provider can service a geographic area?

One way that uniqueness can be guaranteed is to use a URI; another is a URN, with the namespace managed by ICANN and registrars, so we don't have to deal with it. So a pge program might be "http://www.pge.com/drprograms/CBP".

In passing, the examples in Appendix D all refer to PGE programs. Surely there are more? We'll need to survey a broader range including from the ISO/RTO and aggregator perspective.

(b) A facility has exactly one "uttility" and may participate in zero or more "programs".  If a facility works with one or more aggregators (for DR or DER), then this model and the schemas appear to break. A more general model appears to be required.

Following the NYT article that Rish sent to the list (http://lists.oasis-open.org/archives/energyinterop/200908/msg00040.html, linking to http://www.nytimes.com/external/venturebeat/2009/08/14/14venturebeat-power2switch-lets-consumers-choose-their-ele-62417.html ), and looking at the situation as I understand it in Europe and (in part) Texas, this relationship needs to be explored. What if a facility can choose among several providers (whether "utilities" or "aggregators")?

(c) The "programs" listed reflect those that a real utility apparently has in place. Are these suitable for standardization, or as a base set of standardized "programs"?

(d) I hate to say roles and actors (as in the recent email conversation started by Toby at http://lists.oasis-open.org/archives/energyinterop/200908/msg00043.html ). But the roles and relationships that are implicit in the CEC and CD01 versions need to be tackled head on. This is also critical for the security model (PDF page 129, printed page number 113 in CEC). The security model needs to be applied to composable fine-grained security rather than a series of "secure pipes" using SSL (which, incidentally, was superceded by TLS some years ago). So there's work needed to develop the relevant security model and policies for CD02.

(e) CEC version disclaims any "semantics" (PDF page 22) but describes "programs" that have specific meaning. We need to resolve that issue. IMO, the meaning and expected response to the messages is the "semantics" -- and we need a discussion on this soon. (CD01 on lines 795 et seq discusses "Energy Interoperability Semantics").

Thanks!

bill

--
William Cox
Email: wtcox@CoxSoftwareArchitects.com
Web: http://www.CoxSoftwareArchitects.com
+1 862 485 3696 mobile
+1 908 277 3460 fax