Subject: [salud] Improving the wording of section 8

From: "Worley, Dale R (Dale)" <[email-masked]>
Date: Mon, 20 Feb 2012 16:42:57 -0500

Here are some changes that I think would improve how section 8 reads.
The changes are marked with >>> and <<<.

8.  Non-normative Algorithm for Handling Combinations of URNs

   >>>The following text is a non-normative example of an algorithm for
   handling combinations of URNs that complies with the requirements
   in section 7.  Thus, it demonstrates that requirements in section 7
   are consistent and implementable.  (Of course, a device may use any
   other algorithm which complies with section 7.)<<<

...

   The algorithm proceeds by considering each URN in the received
   Alert-Info header from left to right, while revising a set of
   signals.  The set of signals starts as the entire set of signals
   available to the device.  Each URN excludes some signals from the
   set, and *sorts* the signals that remain in the set according to
   how well they represent the URN.  >>>(The details of these
   operations are described below.)<<<  The first URN is the "major
   sort", and has the most influence on the position of a signal in
   the set. ...

...

   At the end of the algorithm, a final, "most minor" sort is done,
   which orders the signals which have been tied under all the sorts
   driven by the URNs.  >>>This final sort places the least specific
   signals (within their groups) *first*.  (If one signal's position
   in each category tree is ancestral or the same as a second signal's
   position in that tree, the first signal is "less specific" than the
   second signal.  Other cases are left to the implementation to
   decide.)<<<

...

   Here is how a single sort step proceeds, examining a single URN to
   modify the set of signals (by excluding some signals and further
   sorting the signals that remain):

   >>>[a number of minor changes]

   o  The URN specifies a specific node in a specific category tree.

   o  All signals in the set that are positioned at that node, or at
      an ancestor node of the URN, are kept.  All other signals are
      removed from the set.

   o  Within any group of signals that are tied under the previous sorts,
      place first those which are at the node of the URN, place second
      those which are at the parent node of the URN, etc., and place
      last those which are at the root node of the feature tree.
   <<<

I believe that this paragraph can be deleted, if we discuss this point
as section 7.1:

   In cases when the device can render audio and visual (e.g. video or
   text) signals at the same time, the algorithms as we have been
   discussing them would work correctly if we consider that the input
   set of signals is a set of *pairs*, each pair containing an audio
   component and a visual component, and the input set of pairs contains
   all possible pairs of audio and visual components.

Dale