- From: Martin Hepp <martin.hepp@ebusiness-unibw.org>
- Date: Thu, 9 Sep 2010 18:17:31 +0200
- To: Michael Uschold <uschold@gmail.com>
- Cc: semantic-web@w3.org, Pat Hayes <phayes@ihmc.us>
Hi Michael,
I agree with your trade-offs. However, just clarifying my point: The
VSO does simply not say that a Kayak need to be considered a "boat".
It does not make a kayak a non-boat. Such is IMO also following the
principle of minimal ontological commitment.
>> IMHO it is dangerous to stray far from common sense - it is too
>> expensive in scaring users away by getting surprising and incorrect
>> behavior in applications.
I assume you are not stating that the VSO is "far from common sense",
are you?
>> IMHO catering too much to the whims of inference engines and making
>> life easy for web developers often results in an unfortunate amount
>> of messiness in an ontology.
I assume you are not stating that the VSO is "messy", are you?
Side note: The relevance of a strict class hierarchy for Web
ontologies is, IMO, very much overrated in Semantic Web research. The
top-level ontological distinctions are very important for reusing data
(e.g. keeping book titles and book copies apart), but not for search.
Who will search for things as generic as a "human-powered arm
vehicle"? If you want to rent a kayak, you will search for kayaks and
not any type of boat.
So I would say that the subject of discussion - whether kayaks are
always boats or not - it not a particularly important axiom.
Martin
On 09.09.2010, at 06:09, Pat Hayes wrote:
>
> On Sep 8, 2010, at 4:26 PM, Michael F Uschold wrote:
>
>> There are various tradeoffs:
>> • Conceptual simplicity of the ontology,
>> • for easy understandabilty
>> • for ease of use
>> • Alignment with common sense
>> • for easy understandabilty
>> • to avoid repelling potential users
>> • Ontological correctness which should correlate with 2. but may
>> be at odds with 1.
>> • to align with common sense
>> • to increase correctness and scope of usability
>> • more correct can often mean more complex
>> • Keeping things nice for inference engines
>> • to improve functionality in an application
>> • Keeping things nice for [semantic] web developers and programmers
>> • to encourage use
>> IMHO it is dangerous to stray far from common sense - it is too
>> expensive in scaring users away by getting surprising and incorrect
>> behavior in applications.
>>
>> IMHO catering too much to the whims of inference engines and making
>> life easy for web developers often results in an unfortunate amount
>> of messiness in an ontology.
>>
>> On Mon, Aug 30, 2010 at 11:36 PM, Martin Hepp <martin.hepp@ebusiness-unibw.org
>> > wrote:
>> Hi Michael,
>> Thanks for the feedback! I chose to consider Kayaks as a special
>> kind of watercraft in order to exclude them from the domain of all
>> properties associated with having a motor, because to my knowledge,
>> kayaks are extremely rarely powered by an engine (other than e.g.
>> canoes, which occasionally have small electric or combustion
>> engines).
>>
>> This seems to be trading off ontologically correctness and
>> alignment with common sense for simplicity and making things nice
>> for web programmers and inference engines. I am all in favor of
>> simplicity to encourage use, but I think it is dangerous to be too
>> out of alignment with common sense - which says a kayak is a boat.
>>
>>
>> By simply also making kayak a subclass of boat, one would recommend
>> (*) a lot of properties that 99.9% of the kayaks in the world don't
>> have (engine displacement etc.), which will irritate potential
>> adopters.
>>
>> Otherwise, I would have needed rather "ontology expert" classes
>> like "motorizableWaterVehicle" etc. This would also require complex
>> class definitions for the range / domain definitions, which cause
>> practical problems in many pure RDF and RDFS environments (e.g.
>> resolving unionOf without an OWL reasoner is a pain for developers).
>>
>> You seem to be using the term "boat" to mean "motorizable water
>> vehicle". I agree that "motorizable water vehicle" is not very
>> natural or simple, even if it is ontologically correct.
>
> Um... don't the (natural) categories of powered boat, sailboat and
> rowboat capture the needed distinctions here quite adequately? I
> have no idea whether a kayak is usually called a rowing boat, but it
> clearly belongs in a natural class of boats propelled by arm muscles
> holding a paddle or oar. BTW, there are, or once were, sea-going
> ships in all these three categories.
>
> Pat Hayes
>
>
>> I agree that there can be domain and range issues. I always cringe
>> at examples like this where we cater to the whims of the language
>> and the reasonsers at the cost of common sense.
>>
>> You have thought about it longer than I, but intuition and
>> experience suggests there is likely a way to keep things reasonably
>> simple and also aligned with common sense.
>>
>>
>>
>> So it was really just a decision for bringing order to the domains
>> and ranges of typical properties.
>>
>> I hope this modeling compromise is acceptable for all kayakers in
>> the world.
>>
>> Martin
>>
>> (*) I am well aware of the specific semantics of rdfs:range and
>> rdfs:domain ;-)
>> (**) I know that you know that I am not saying that a kayak is not
>> a boat but just that a kayak does not always need to be a regular
>> boat for everybody ;-)
>>
>>
>> On 30.08.2010, at 20:36, Michael F Uschold wrote:
>>
>> Overall this ontology is just fine, highly suitable for its
>> intended purpose. I do have one [hopefully] minor concern. Why is
>> a kayak not a kind of a boat? The classification in this ontology
>> goes like this:
>> • Watercraft
>> • Boat
>> • Kayak
>> • Ship
>> The source of this (IHMO) mistake may be in the WIkipedia entry for
>> Watercraft:
>>
>> However, there are a number of craft which many people would
>> consider neither a ship nor a boat, such as:canoes, kayaks, rafts,
>> barges, catamarans, hydrofoils, windsurfers, surfboards (when used
>> as a paddle board), jet skis, underwater robots, seaplanes, and
>> torpedoes.
>>
>> Contradictorily, the opening words in the definition of kayak in
>> Wikipedia clearly state that a kayak is a boat:
>> A kayak (sometimes generalised as a canoe) is a small human-powered
>> boat that traditionally has a covered deck, and one or more
>> cockpits, each seating one paddler who strokes a double-bladed
>> paddle.
>>
>> I have been a kayaker for 35 years, and every kayaker I know thinks
>> and speaks of their kayak as a kind of boat. In the US, most
>> whitewater kayakers consider themselves boaters.
>>
>> What competency question justifies this classification?
>> What is an example of a kayak that is categorically not a boat?
>>
>> Michael
>>
>>
>>
>> On Mon, Aug 30, 2010 at 10:22 AM, Martin Hepp <martin.hepp@ebusiness-unibw.org
>> > wrote:
>> Dear all:
>>
>> I am happy to announce the first mature release of the Vehicle
>> Sales Ontology [1], a GoodRelations-compliant [2,3] Web vocabulary
>> for
>> - Cars,
>> - Bikes,
>> - Boats,
>> - etc.
>> on the Web of Data.
>>
>> It can be used by car listing sites, bike or canoe rental services
>> and the like.
>>
>> In combination with
>>
>> - http://purl.org/goodrelations/v1#owns and
>> - http://purl.org/goodrelations/v1#seeks ,
>>
>> it is also possible to expose ownership ("I own a Volkswagen Golf")
>> as part of online identity data or purchasing interest ("I am
>> looking for a canoe").
>>
>> The ontology recommends DBPedia resource URIs as predefined
>> qualitative values as much as possible.
>>
>> Any feedback is very welcome.
>>
>> Best wishes
>>
>> Martin
>> [1] http://purl.org/vso/ns
>> [2] http://purl.org/goodrelations/v1
>> [3] http://www.ebusiness-unibw.org/wiki/
>> Own_GoodRelations_Vocabularies
>>
>>
>> --------------------------------------------------------
>> martin hepp
>> e-mail: mhepp@computer.org
>> www: http://www.heppnetz.de/
>> skype: mfhepp
>> twitter: mfhepp
>>
>> Check out GoodRelations for E-Commerce on the Web of Linked Data!
>> =================================================================
>> * Project Main Page: http://purl.org/goodrelations/
>> * Quickstart Guide for Developers: http://bit.ly/quickstart4gr
>> * Vocabulary Reference: http://purl.org/goodrelations/v1
>> * Developer's Wiki: http://www.ebusiness-unibw.org/wiki/GoodRelations
>> * Examples: http://bit.ly/cookbook4gr
>> * Presentations: http://bit.ly/grtalks
>> * Videos: http://bit.ly/grvideos
>>
>>
>>
>>
>> --
>> Michael Uschold, PhD
>> LinkedIn: http://tr.im/limfu
>> Skype: UscholdM
>>
>>
>>
>>
>> --
>> Michael Uschold, PhD
>> LinkedIn: http://tr.im/limfu
>> Skype: UscholdM
>
> ------------------------------------------------------------
> IHMC (850)434 8903 or (650)494
> 3973
> 40 South Alcaniz St. (850)202 4416 office
> Pensacola (850)202 4440 fax
> FL 32502 (850)291 0667 mobile
> phayesAT-SIGNihmc.us http://www.ihmc.us/users/phayes
>
>
>
>
Received on Thursday, 9 September 2010 16:18:05 UTC