DrDC Game Technical Matters: Use of OWL-DL for Game Ontology
DrDC Game Technical
Matters
The DrDC game is to be
played on the WWW. Like all games it has rules and a playing field which we call
the magic circle.
Magic
Circle:
The WWW itself provides
the basic ground for the playing. But we need to restrict it in some way in
order that players will know when they are on the playing field or not. In other
words we need to define the magic circle of play. This is a matter of current
research. Currently, rules are used to define the magic
circle.
Rules:
Let
us imagine that Google is the only search engine permitted? This is like saying
that a ball can only be kicked with the feet and not touched by the hands in the
game of football. Searching with Google certainly limits the type of play but
not much.
Let us imagine that any
player is permitted to search in their own language as well as the lingua franca
(English). For definiteness, suppose that two players agree to use Gaeilge and
Bulgarian, in addition to English. Then to a certain extent use of these
languages also restricts the magic circle. Some of the rules of play have
already been introduced earlier in this issue of the
Journal.
Computability:
Since
the DrDC game lives in a digital world on the WWW it is natural that all
relevant matters concerning computability should be addressed. For the past year
we have been focussing on the transcription or recording of games. We have
assumed that the played game will be available to anyone on the WWW in a form
that will enable them to replay it in order to learn how such a game is played
or to gain further experience, much as one might do to learn or improve in the
playing of chess. But we need to do more for computability. In order that search
engines (such as Google) can make “cultural” connections
independently of human intervention our DrDC games must conform to the Semantic
Web Ontology Language: OWL. [http://www.w3.org/2004/OWL/]. For practical
research purposes we are using a free Ontology editor: Protégé and the
OWL plugin, available from Stanford University
[http://protege.stanford.edu/plugins/owl/].
OWL-DL
For
the DrDC Ontology we deliberately restrict ourselves to that OWL based on
Description Logics (DL), the latter being “a family of knowledge
representation (KR) formalisms that represent the knowledge of an application
domain (the “world”) by first defining the relevant concepts of the
domain (its terminology), and then using these concepts to specify properties of
objects and individuals occurring in the domain (the world description).”
(Baader et al. 2003, 43).
A
simple example or two of OWL-DL will
help:
Ō
hasKeyword. Butterfly -- individual games having butterfly as a
keyword
ÅÕ
hasKeyword. Butterfly -- individual games all of which have butterfly as a
keyword.
The concept of
Butterfly Game may then be defined by the concept expresion
Ō
hasKeyword. Butterfly
⊓
∀
hasKeyword. Butterfly,
which
denotes the set of individual games having at least one filler of the role
hasKeyword belonging to the concept Butterfly and moreover, every filler of the
role hasKeyword must be a
Butterfly.
Let us now put
together the concepts of URL and Image, both of which are key elements of a DrDC
game. The corresponding roles are hasURL and hasImage, respectively. Consider
the concept defined by the DL expression (≥2 hasImage)
⊓
(≤ 3 hasURL). This represents the concept of “individual games
having at least 2 images and at most 3 URLs.” It is clear to see that the
Ohrid Game is such a game. In the actual Ontology we are constructing we use a
very general role called hasKey. Subroles of this are hasKeyword, hasKeyphrase,
and hasKeyimage. We can imagine that the Key element to a game might be an image
rather than a word.
Corresponding
to each role, such as hasKeyword, there is an inverse role, isKeywordOf. Details
of the OWL-DL Ontology for the DrDC game will eventually be released into the
public domain
at
http://homepage.mac.com/micheal1/iblog/B1888672450/index.html
Posted: Thu - September 1, 2005 at 03:23 p.m.