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Re: Semantics Attributes: XLink CR03062000

From: Hartmut Obendorf <hartmut@obendorf.de>
Date: Wed, 15 Nov 2000 11:20:03 -0000
To: <www-xml-linking-comments@w3.org>
Message-ID: <LPBBKJNMAJPPLFOGMFKKAECGCBAA.hartmut@obendorf.de>
Hello again,

first of all, thank you for answering some of my questions. (This did
create new ones though, I'm afraid :)

Sorry it took me so long to answer, but I had to reread some old
discussions about link functionality I found in the Hitachi newsgroup.

To get immediately to the point:

> >If the example in 5.2 "Simple link functionality done with an extended
> >link" is correct, the most important title for a link (the only one left
> >in simple links) would be the title for the target locator. As I pointed
> >out before, I would have thought the main feature describing the
> >semantic relationship is the attribute "arcrole".
> >
> >I would argue that the title of the arc is more important than the
> >locator's.
> So are you intending to make the case that we should remove the
> ability to
> specify ending resource roles on simple links?  I believe the WG
> discussed
> this exact proposal about a year ago, but I'd have to look it up.  If you
> actually make this proposal, that will force me to do so. :-)

yes, I would like to have something changed.

I will try to explain why:

  - you have four types of "roles":

> In order to facilitate sophisticated processing and traversal by
> XLink-aware applications, XLink allows link authors to provide "role"
> information for the following constructs:
> - A link as a whole (if expressed as an extended link)
> - A starting resource (if it is in an extended link)
> - An ending resource (whether in a simple or an extended link)
> - An arc (whether in a simple or an extended link)

  - you have four types of titles - one for each "role"

  - you allow two types of "roles" for simple links
    (role: ending resource "role", arcrole: arc "role")

  - you only allow one type of title for simple links
    (for the ending resource)

Though there might be some good reasons to do so, I don't see
them and so it seems to be a bit arbitrary to me.

For one, you keep more than one role for simple links but drop
the corresponding title element. If titles should help humans
to understand the purpose of the link better, why drop that
information? On the other hand, will it really help humans to
have the machine select one of a large number of titles for them?

Let's take a look at your scenario:
> You are reading a document about the game of Go.  In the text, the word
> "tesuji" (a kind of Go move) is mention.  The word serves as the starting
> resource for several arcs (created in extended links, with this starting
> resource being remote): One takes you to an illustration of the move,
> another takes you to a definition of the word, another takes you to the
> etymology of the word, and so on.

This are all functions "in relation to" the starting element - arc roles?

> If all these arcs came from random third-party links created by several
> link authors, it might be useful and sufficient to display their link
> titles in a pop-up dialog when the user right-clicks on the word.  But if
> the arcs were specified in the same link, it would not be sufficiently
> helpful to the reader to display the link title; you'd probably want to
> display the titles of the different arcs.

Is it really information the user expects to see, if he is asked to choose
between "link titles" (corresponding to link "roles" - which

 #cross-citation from Re: Introductory comments..
 >>A role for a whole link might suggest a particular interpretation that a
 >>link processor should have when handling the link or a particular
 >>"template" that such links should follow; e.g., a role of ".../twins"
 >>allow processors to rely on the fact that the resources will be supplied
 >>pairs in this type of link.

seem to be intended for link processing, not for humans)?
To be exemplary: Will it be more useful for users to choose between a "twin"
link and a "single" link than between "illustration" and "definition" -
corresponding titles to arc roles?

 >>A title for a whole link might be displayed in preference to other levels
 >>of title (or used when no other titles are provided).
This seems to be a rather bad idea: I don't believe that the function of the
different types of titles should be interchangeable - it is hard enough for
a link author to seperate the title functions - the user should be made
conscious of the context that the title is valid for (a "twin" link might
mean something completely different..)

> Similarly, two ending resources might (in the absence of arcs) have the
> same title, such as "Person Name", but in the context of arcs, need arc
> titles to distinguish them as "this person's father" and "this person's
> mother".

Same argument - I don't think "Person Name" is not a useful information -
but I believe "this person's father" is much more helpful.

> However, I can understand how there could be some confusion!

I think that this confusion could be decreased:

I would suggest to either drop the "role" for the ending resource
in simple links or add another title.

I would suggest to use the title in simple links like an arc title in
extended links.

I would prefer the use of "class" for "link roles".

I would prefer the use of "type" for "starting/ending resource roles".

> I found it helpful.  I hope you did.

I sure enjoyed your answers and again hope this will be of use..


  Hartmut Obendorf                    mailto:hartmut@obendorf.de
  Graduate Student                        http://www.obendorf.de
  Distributed Systems Group
  Universitay of Hamburg
Received on Wednesday, 15 November 2000 05:20:53 UTC

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