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Re: Dilbert example - defining hasCubicle

From: Jeremy Carroll <jeremy@topquadrant.com>
Date: Thu, 13 Oct 2011 11:16:24 -0700
Message-ID: <4E972AF8.2030800@topquadrant.com>
To: public-rdf-wg@w3.org
Dan

to push your thought experiment a bit further, we could have cube moves 
every day, or four times a day.
By this point the importance of time in cube assignments is very clear, 
and this should be modelled.

However, if the cube moves are once a decade, then the blib in the model 
during the move is probably unimportant, and the simpler model is 
probably 'better'

But aren't modelling choices all about what your application goals are - 
there is no one true way to see the world.
Let's suppose the application we are interested in, is sandwich 
delivery, then if there is a cube move every day, the sandwich for Alice 
should go to Alice's current cube, and modelling the cube move itself is 
unnecessary.

In fact, I have actually worked with such a system of cube moves, it's 
called 'hot desking'.
The actual data recorded was:
- entry and exit time for each employee
- while the employee is "in" the hot desk area their desk assignment is 
recorded simply by their coat being on the chair

This system would not support the sandwich delivery app.

Jeremy


On 10/13/2011 9:34 AM, Dan Brickley wrote:
> Pat, (well, everyone; but triggered by Pat's comments)
>
> You're suggesting if I read you right, that RDF shouldn't be written
> in ways that make it's truth context-dependent; e.g. that a 'date of
> birth' property is preferable by far to an 'age' property.
>
> Below is a sketch of a reasonably common descriptive scenario. Could
> you maybe suggest a modelling / descriptive idiom that avoids these
> problems? I hope it anchors some of the
> issues we've discussed in a small enough example that might be turned
> into concrete decision test cases or example documentation.
>
> Dan
>
> -----
>
> Theory and Practice
>
> Consider an RDF vocabulary for describing office assignments in the cartoon
> universe inhabited by Dilbert<http://en.wikipedia.org/wiki/Dilbert>.
> First I describe the universe, then some ways in
> which we might summarise what's going on using RDF graph descriptions.
> I would love to get a sense for any
> 'best practice' claims here. Personally I see no single best way to
> deal with this, only different and annoying tradeoffs.
>
> So --- this is a fictional highly simplified company in which workers
> each are assigned to occupy exactly one cubicle,
> and in which every cubicle has at most one assigned worker. Cubicles
> may also sometimes
> be empty.
>
> * Every 3 months, the Pointy-haired boss
> <http://en.wikipedia.org/wiki/List_of_Dilbert_characters#Pointy-haired_boss>
>    has a strategic re-organization, and re-assigns workers to cubicles.
> * He does this in a memo dictated to Dogbert, who will take the boss's
> vague and forgetful instructions and compare them
>    to an Excel spreadsheet. This, cleaned up, eventually becomes an
> emailed Word .doc sent to the all-staff@ mailing list.
>    The word document is basically a table of room moves, it is headed
> with a date and in bold type "EFFECTIVE
>    IMMEDIATELY", usually mailed out mid-evening and read by staff the
> next morning.
> * In practice, employees move their stuff to the new cubicles over the
> course of a few days; longer if they're
>    on holiday or off sick. Phone numbers are fixed later, hopefully. As
> are name badges etc.
> * But generally the move takes place the day after the word file is
> circulated, and at any one point, a given
>    cubicle can be fairly said to have at most one official occupant worker.
>
> So let's try to model this in RDF/RDFS/OWL.
>
> First, we can talk about the employees. Let's make a class, 'Employee'.
>
> In the company systems, each employee has an ID, which is 'e-' plus an
> integer. Once assigned, these are
> never re-assigned, even if the employee leaves or dies.
>
> We also need to talk about the office space units, the cubes or
> 'Cubicles'. Let's forget for now that
> the furniture is movable, and treat each Cubicle as if it lasts
> forever. Maybe they are even somehow symbolic
> cubicle names, and the furniture that embodies them can be moved
> around to diferent office locations. But we
> don't try modelling that for now.
>
> In the company systems, each cubicle has an ID, which is 'c-' plus an
> integer. Once assigned, these are
> never re-assigned, even if the cubicle becomes in any sense de-activated.
>
> Let's represent these as IRIs. Three employees, three cubicles.
>
>   * http://example.com/e-1
>   * http://example.com/e-2
>   * http://example.com/e-3
>   * http://example.com/c-1000
>   * http://example.com/c-1001
>   * http://example.com/c-1002
>
> We can describe the names of employees. Cubicicles also have informal
> names. Let's say that neither change, ever.
>
>   * e-1 name 'Alice'
>   * e-2 name 'Bob'
>   * e-3 name 'Charlie'
>   * c-1000 'The Einstein Suite'.
>   * c-1001 'The doghouse'.
>   * c-1002 'Helpdesk'.
>
> Describing these in RDF is pretty straightforward.
>
> Let's now describe room assignments.
>
> At the beginning of 2011 Alice (e-1) is in c-1000; Bob (e-2) is in
> c-1001; Charlie (e-3) is in c-1002. How can
> we represent this in RDF?
>
> We define an RDF/RDFS/OWL relationship type aka property, called eg:hasCubicle
>
> Let's say our corporate ontologist comes up with this schematic
> description of cubicle assignments:
>
>   * eg:hasCubicle has a domain of eg:Employee, a range of eg:Cubicle.
>   * it is an owl:FunctionalProperty, because any Employee has at most
> one Cubicle related via hasCubicle.
>   * it is an owl:InverseFunctionalProperty, because any Cubicle is the
> value of hasCubicle for no more than one Employee.
>
> So... at beginning of 2011 it would be truthy to assert these RDF claims:
>
>   *<http://example.com/e-1>  <http://example.com/hasCubicle>
> <http://example.com/c-1000>  .
>   *<http://example.com/e-2>  <http://example.com/hasCubicle>
> <http://example.com/c-1001>  .
>   *<http://example.com/e-3>  <http://example.com/hasCubicle>
> <http://example.com/c-1002>  .
>
> Now, come March 10th, everyone at the company receives an all-staff
> email from Dogbert, with cubicle reassignments.
> Amongst other changes, Alice and Bob are swapping cubicles, and
> Charlie stays in c-1002.
>
> Within a week or so (let's say by March 20th to be sure) The cubicle
> moves are all made real, in terms
> of where people are supposed to be based, where they are, and where
> their stuff and phone line routings are.
>
> The fictional world by March 20th 2011 is now truthily described by
> the following claims:
>
>   *<http://example.com/e-1>  <http://example.com/hasCubicle>
> <http://example.com/c-1001>  .
>   *<http://example.com/e-2>  <http://example.com/hasCubicle>
> <http://example.com/c-1000>  .
>   *<http://example.com/e-3>  <http://example.com/hasCubicle>
> <http://example.com/c-1002>  .
>
>
> Questions / view from Named Graphs.
>
> 1. Was it a mistake, bad modelling style etc, to describe things with
> 'hasCubicle'? Should we have instead
> described a date-stamped 'CubicleAssignmentEvent' that mentions for
> example the roles of Dogbert, Alice,
> and some Cubicle? Is there a 'better' way to describe things? Is this
> an acceptable way to describe things?
>
> 2. How should we express then the notion that each employee has at
> most one cubicle and vice versa? Is this
> appropriate material to try to capture in OWL?
>
> 3. How should a SPARQL store or TriG++ document capture the different
> graphs describing the evolving state of the
> company's office-space allocations?
>
> 4. Can we offer any practical but machine-readable metadata that helps
> indicate to consuming applications
> the potential problems that might come from merging different graphs
> that use this modelling style?
> For example, can we write any useful definition for a class of
> property "TimeVolatileProperty" that could help
> people understand risk of merging different RDF graphs using 'hasCubicle'?
>
> 5. Can the 'snapshot of the world-as-it-now-is' view and the
> 'transaction / event log view' be equal citizens, stored in the same
> RDF store, and can metadata / manifest / table of contents info for
> that store be used to make the information usefully exploitable and
> reasonably truthy?
>
Received on Thursday, 13 October 2011 18:16:48 GMT

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