On 20/5/09 07:44, David Huynh wrote:
Sherman Monroe wrote:
>> That's when I was turned on
to Frame Semantics, which I immediately praised, it is by far the most
expressive and elegant knowledge representation framework for NL I
have come across (although, it's been 3 or 4 years since I really
looked). In short, frame semantics sees all sentences as a "scene"
(like a movie scene) and the nouns all play "roles" in that scene.
E.g. a boy eating is involved in a ConsumeFood scene, and the actors
are the boy, the utensil he uses, the food, the chair he sits in. So I
choose framesemantics as the KB model for Cypher grammar parser output.
Thanks, Sherman, for your story. I had a "history" with Semantic Web
technologies, too, since 2001. Data on the Web is inevitable. I just
want to figure out ahead of time what it will actually be like.
This sent off lightbulbs for me, I went back to RDF, and saw that, low
and behold, frames can be represented as RDF, the scene types being
classes, a scene instance (i.e. the thing representing a complete
sentence) being the subject, the property is the role, and the object
is the thing playing that role, e.g:
EatFrame023 rdf:type mlo:EatFrame
EatFrame023 mlo:eater someschema:URIForJohn
EatFrame023 utensil someschema:JohnFavoriteSpoon
EatFrame023 mlo:seatedAt _:anonChair
EatFrame023 foaf:location someschema:JohnsLivingRoom
EatFrame023 someschema:time _:01122
EatFrame023 truthval "false"^booleanValueType
dbpedia:Heroes(Series) rdf:type dbpedia:TVShow
dbpedia:Heroes(Series) dbpedia:showtime _:01122
_:01122 rdf:type types:TimeSpan
_:01122 types:startHour "20"^num:PositiveInteger
_:01122 types:startMinutes "00"^num:PositiveInteger
_:01122 types:endHour "21"^num:PositiveInteger
_:01122 types:endMinutes "00"^num:PositiveInteger
_:01122 types:timezone "EST"
This says: /No, John didn't eat in a sandwich in a chair in his living
room using his favorite spoon, during the TV show Heroes/. Do you
still believe RDF is incapable of expressing complex NL statements?
Yes, I still believe. :)
Skeptical? Me too, here. You have to be pretty careful with negations
expressed over representations that are shipped around in RDF triples.
>> EatFrame023 rdf:type mlo:EatFrame
>> EatFrame023 mlo:eater someschema:URIForJohn
>> EatFrame023 utensil someschema:JohnFavoriteSpoon
>> EatFrame023 mlo:seatedAt _:anonChair
>> EatFrame023 foaf:location someschema:JohnsLivingRoom
>> EatFrame023 someschema:time _:01122
>> EatFrame023 truthval "false"^booleanValueType
What happens when you add properties to EatFrame023, or when you remove
properties from the description? If the above is true, can I take it,
omit ">> EatFrame023 utensil someschema:JohnFavoriteSpoon" and pass it
along to some downstream system in a context that suggests it remains a
true description?
Detail aside: yes, event-centric descriptions are pretty seductive. In a
world where everything is constantly changing, at least a true
description of an event seems something that is timelessly true. But
they can be super-slippery to compute with, especially in a world of
partial, fragmented descriptions. They're also hard to manage w.r.t. to
identification: given two descriptions of an event or frame, how do you
know whether they refer to different ones? etc.
My dabbling with event modelling came through
http://www.ilrt.bris.ac.uk/discovery/harmony/docs/abc/abc_draft.html
where we tried to explore the resolution of some tensions between Dublin
Core and other metadata vocabularies by articulating everything in terms
of events. It is very appealing, but ultimately I think the problem with
describing everything in terms of a giant "what happened?" log is that
it doesn't directly tell you what the state of the world is at any
point. And that's what many information consumers (human or mechanical)
more often need.
/What
happens if all the worlds databases (e.g. Oracle, Mysql, etc databases
out there) could be directly connected to one another in a large
global network, all sharing one massive, distributed schema, and
people were able to send queries to that network using a Esperanto for
SQL?/ The ability of RDF to represent (not sentences but) rows and
columns of any database schema imaginable means it can deliver this
vision, and the value tied to it.
And look what happened to Esperanto... After one century, 2 million
speakers, or 0.025% of the world population.
[...]
Media are notoriously hard to understand, from what I can understand. If
we were to say that television was radio but "just" with images, then we
would be missing something huge. Or that printing was writing but "just"
much faster. Or that writing was speech "just" recorded on paper.
Or that SPARQL is "just" Esperanto for computers? The metaphor is nice
but ... just that. As you point out, even non-metaphorical conceptual
shortcuts can mislead us. Sometimes metaphors can inspire us and show a
glimpse of the bigger picture. But I don't think they so often help us
predict what'll actually happen.
Consumer digital cameras are cameras, but just smaller and cheaper and
faster to develop. Cell phones are phones but just without cords. Etc.
etc. Is the Data Web the Web just with data? Just for machines? Is the
difference just that the user can now combine data from several sources?
How often is that desirable? (Think of your experience today: how often
would you be willing to pay $1 for RDF from some web page? Daily?
Weekly? Monthly?) What are the second-order effects?
And money is just written promises :)
cheers,
Dan
