UPD Mail Archive: UPD> RE: PS> Semantic model: media hand

UPD> RE: PS> Semantic model: media handling

From: Harry Lewis (harryl@us.ibm.com)
Date: Wed Jul 17 2002 - 11:34:40 EDT

  • Next message: NorbertSchade@oaktech.com: "UPD> data type separation"

    I like Bob's analysis. I think the Semantic Model will be most useful
    taking this approach.
    Harry Lewis
    IBM Printing Systems

    "TAYLOR,BOB (HP-Vancouver,ex1)" <robert_b_taylor@hp.com>
    Sent by: owner-ps@pwg.org
    07/16/2002 09:13 PM
            To: Norbert Schade <norbertschade@attbi.com>, Print Services group
            cc: UPD group <upd@pwg.org>
            Subject: RE: PS> Semantic model: media handling


    Hi Norbert, all,
    One of the things we (HP) have been suggesting for the semantic model is
    the separation of the raw "attribute/element" definitions from the
    structures/model that pull them together for a particular use. As you
    not, UPDF has done this structuring in a different way than IPP - which is
    also somewhat different than UPnP & PSI, etc. I'm not sure we want to try
    codify any one structure as part of the core semantic model - these will
    tend to vary by market segment and domain, and I'm not sure we can do this
    one-size-fits-all. What we would like to see, though, is common
    definition of the
    core "attributes/elements" - this seems much more reusable across models &
    domains. It does make sense, though, to publish some of the "common
    models" as at least examples of structural models - IPP, UPDF, etc. are
    likely candidates for this. This exposes some of useful constructs (such
    as the composite feature you describe below) for reuse.
    Bob Taylor
    Senior Architect
    IPG Strategic Technology Development
    Hewlett-Packard Co.
    phone: 360.212.2625/T212.2625
    fax: 208.730-5111
    -----Original Message-----
    From: Norbert Schade [mailto:norbertschade@attbi.com]
    Sent: Monday, July 08, 2002 7:32 AM
    To: Print Services group
    Cc: UPD group
    Subject: PS> Semantic model: media handling

    I have problems to follow two different ways to specify media handling and
    UPDF would have problems to support that.
    I'm fine with the specification of single media attributes like size,
    type, etc.
    I agree that there should exist a media instance a level higher, which is
    a media element with a number of media attributes.
    The number of attributes can vary. In one sample it may be just size and
    type, in another it may be something like the IPP media collection.
    My point is that the attributes a media is described by may vary.
    There should not be a predefined media collection in a common Semantic
    Model representing one implementation.
    Feel free to check the composite feature definition we have in UPDF. Open
    the UPDF.xsd schema to do this and follow the path down to
    PrintCapabilities.Features. The current sample description xml of an
    imaginary LJ9000 has a 'Media' composite feature. We can compose any
    number of features to a new feature, be it Media, Quality or anything
    else. This is a very flexible structure and is expected to be used
    frequently. We got very positive feedback once we finished it last year.
    We'd appreciate if the Semantic Model does something down that path.
    Otherwise the spec is ambiguous.
    Another statement:
    We've seen the current schema of the Semantic Model. We know there are a
    number of ways to write schemas. The UPDF group made the experience that
    working with attributes instead of assigning text to elements directly has
    advantages. Validation is easier and we can define constraints (these are
    really constraints and not dependencies) for attributes. You may think
    that over.
    Norbert Schade
    69 Prescott Drive
    North Chelmsford, MA 01863

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