FWD: ASN.1/XML Presentation from XML Europe 2003

["R. Allen Wyke" <emtc@nc.rr.com>]

Some good stuff in this presentation the IF could might want to think about... 

> > From: Art Botterell <acb@incident.com>
> > Date: Sun May 11, 2003  9:07:33 PM US/Eastern
> > To: allenwyke@nc.rr.com
> > Subject: Fwd: [asn1xml] XML Europe 2003
> >
> > I imagine you've seen this?
> >
> >> Date: Thu, 08 May 2003 13:14:08 +0100
> >> From: John Larmouth <j.larmouth@salford.ac.uk>
> >> To: asn1dev@oss.com, asn1xml <asn1xml@oss.com>
> >> Subject: [asn1xml] XML Europe 2003
> >>
> >> I attach the slides I used for this presentation (you will have seen 
> >> some before!).
> >>
> >> It went down pretty well, but the audience was only about forty 
> >> people (five parallel sessions).  But I got quite a few nods on some 
> >> of my points, such as discussion of the importance of canonical 
> >> encodings, and the statement that if we had patented TLV in 1980 XML 
> >> would not exist today!  (Or at least, would have been in violation of 
> >> the TLV patent on nested self-identifying and self-delimiting 
> >> elements in an encoding.)
> >>
> >> Two or three people came up aftwerwards and said how much they had 
> >> learned, which was pleasing.
> >>
> >> A number of questions, most were positive or for clarification, with 
> >> only a few slightly awkward questions:
> >>
> >> 	1)	How could ASN.1 claim to be a general-purpose data-modelling 
> >> language when it did not allow the general net represented by ID and 
> >> IDREF?  (I said the concern was with document content, not semantic 
> >> relationships between parts of that content, but that the issue of 
> >> ASN.1 support in this area was still under discussion.)
> >>
> >> 	2)	Had any tool vendors provided a SAX or DOM-like interface to an 
> >> ASN.1 (XER) decoder?  (I ummed and arrghed about commercial 
> >> confidentiallty, but no tool known to be publicly available, but I 
> >> was rescued by another member of the audience who said "No-one in 
> >> their right mind would want a DOM or SAX interface if there was code 
> >> to marshall into a C, C++, or Java datastructure".)
> >>
> >> 	3)	Did I know about the XSD mapping into Java?  (I had to admit I 
> >> did not, but I said that ASN.1 implementors tended to prefer the C 
> >> mapping, as the application ran faster.)
> >>
> >> There were two other presentations that are worth commenting on, both 
> >> given by Henry Thompson, who seems to be very much part of XSD 
> >> standardisation.
> >>
> >> The first was describing "bugs" that were going to be mended in XSD. 
> >> There were three areas that he covered that seem relevant to ASN.1 
> >> work:
> >>
> >> 	a)	XSD is not properly aligned with 8601 for time types, and this 
> >> needs to be addressed.
> >>
> >> 	b)	XSD does not conform to the RFC for Base64, and this needs to be 
> >> mended.
> >>
> >> 	c)	There is a user-demand for relational constraints between parts 
> >> of the document (if this integer field has value 29 that that 
> >> optional element has to be present), and this has to be addressed by 
> >> future work.
> >>
> >> 	d)	There is a demand for being able to specify precision in decimal 
> >> floating-point.
> >>
> >> There were other points, but these were the main ones.  It makes me 
> >> worry about how much work we may have to do in the future in both 
> >> X.693 and X.694 to track XSD.
> >>
> >> The second presentation was also by Henry. (He also attended my 
> >> presentation, and we had a good chat afterwards, and I think we both 
> >> appreciated each other.)  This one was about determinism, and seemed 
> >> also highly relevant to our ASN.1 work (our Annex B).  He has almost 
> >> completed a theoretical mapping (which is being transformed into a 
> >> tool) from XSD into a finite state automata, with the names of XML 
> >> elements as the labels on the state transition arrows.  (What he 
> >> calls "exponents" - repetitions that have both a maxoccurs and a 
> >> minoccurs - give him the most trouble).  Having done the mapping, 
> >> then a lot of old academic stuff can be applied to determine if the 
> >> defined finite state machine is deterministic or not.  Hence you can 
> >> determine whether the XSD is valid or not (in terms of determinism). 
> >> I am not sure whether this is just seen as an academic exercise, or 
> >> whether it may eventually impact the XSD specification.  Clearly the 
> >> same approach could be done to determining formally and precisely 
> >> whether an EXTENDED-XER spec violates determinism or not, but it 
> >> would require work.
> >>
> >> All in all, some interesting sessions, and probably useful publicity 
> >> for ASN.1, but conferences like this are really just too big to get 
> >> to know people if you don't know them already (I said hello to a few 
> >> OASIS people, including Karl and Jon and Mark, and had a chat with 
> >> Patrick the CEO, but there is nothing really to report on that).
> >>
> >> John L
> >>
> >> --
> >> PLEASE NOTE - As an anti-SPAM measure, e-mails will shortly
> >> not be accepted by my machine from an unknown sender unless
> >> the subject contains the phrase "Hi John".
> >>
> >> If you pass my e-mail address to others (which I am very happy
> >> for you to do) please tell them to include this phrase in the
> >> subject line of their first mailing to me.  Thanks.
> >>
> >>    Prof John Larmouth
> >>    Larmouth T&PDS Ltd
> >>    (Training and Protocol Development Services Ltd)
> >>    1 Blueberry Road
> >>    Bowdon                               j.larmouth@salford.ac.uk
> >>    Cheshire WA14 3LS                    (put "Hi John" in subject)
> >>    England
> >>    Tel: +44 161 928 1605		Fax: +44 161 928 8069
> >>
> ----
> 

> >
> -------------------
> R. Allen Wyke
> allenwyke@nc.rr.com
> Fax: 508.526.0729
-- 
R. Allen Wyke
Chair, Emergency Management TC
emtc@nc.rr.com
http://www.oasis-open.org/committees/emergency

xml2003.ppt