Re: [RIFRAF] ACTION 173: Initial Ontology for Action Language Discriminators

Axel (and Leora) - the correct word is "INERTIA". It is used to mean
that things stay unchanged unless explicitly transformed - i.e. frame
axiom. See e.g. http://www.cs.utexas.edu/users/tag/cc/tutorial/describing.html.

-hak

Axel Polleres wrote:

> 
> Leora Morgenstern wrote:
> 
>>
>>
>> public-rif-wg-request@w3.org wrote on 04/25/2007 04:24:57 AM:
>>
>>  >
>>  > Leora Morgenstern wrote:
>>  > >
>>  > > Attached please find the initial pass at an ontology for action
>>  > > languages (Action 173).   > >
>>  > >
>>  > > Some remarks on the ontology.
>>  > >
>>  > > 1.I built my ontology on top of the ontology that Allen Ginsberg had
>>  > > created for Action 173 (ontologizing semantic discriminators). This
>>  > > approach has the advantage of dealing with at least some integration
>>  > > issues from the start, instead of deferring them to a later date.
>>  > >
>>  > > 2. As discussed during earlier telecons, I broadened the original
>>  > > mandate for this action, which was to create an ontology for
>>  > > discriminators for  ECA (event-condition-action) rules, which are 
>> used
>>  > > mainly to describe updates to databases. I looked at the more 
>> general
>>  > > problem of discriminators for AI action languages.
>>  > > These more general action languages would seem to be needed to 
>> represent
>>  > > the use cases in the UCR document. (For example, in the use case 
>> Ruleset
>>  > > Integration for Medical Decision Support, one reasons about various
>>  > > medical events, such as Bob’s Hb1AC levels increasing, the 
>> doctor
>>  > > prescribing various medications, Bob’s reactions to them, 
>> and Bob’s
>>  > > taking a medical test.) ECA rules, which are much narrower in 
>> scope, can
>>  > > be considered a subset of general action rules.
>>  > >
>>  > > Examples of such general AI action languages include the situation
>>  > > calculus, the event calculus, the fluent calculus, temporal action
>>  > > logics, and  the action description languages \cal{A}, and \cal{C}
>>  > >
>>  > > 3. These languages share certain features, but differ on other 
>> features.
>>  > > A list of features of interest follows:
>>  > >     > > a. Division into sets of sentences: domain description, 
>> observation
>>  > > sentences, queries. /(It is almost universally accepted to have 
>> at the
>>  > > first two classes of sentences in action languages.)/
>>  > > b. Intervals vs. time points. vs. both /(E.g., the event calculus 
>> has
>>  > > both time points and intervals; sitcalc has situations/time points,
>>  > > \cal{A} has time points.)/
>>  > > c. Discrete time vs. continuous time /(Situation calculus: discrete
>>  > > time; fluent calculus,  event calculus: continuous time)/
>>  > > d. Branching time vs. linear time; branching forward only vs. 
>> branching
>>  > > both forward and backward /(Event calculus: linear time; situation
>>  > > calculus: forward branching time.)/
>>  > > e. Causation as an explicit relation vs. concept explicit in rule 
>> and/or
>>  > > material implication. /(Explicit in \cal{C}; implicit in temporal 
>> action
>>  > > logics, EC, SC.)/
>>  > > f. Causal rules; state constraints
>>  > > g. Concurrency: concurrency disallowed; concurrent processes 
>> allowed,
>>  > > but can’t have them starting at exactly the same time
>>  > > (asynchronicity).  /(Fluent calculus, event calculus: concurrency
>>  > > allowed; vanilla sitcalc; only one action at a time; extended
>>  > > (Reiter-style) situation calculus: asynchronicity.)/
>>  > > h. Explicit agent vs. implicit agent
>>  > > i. Single agent vs. multiple agent
>>  > > j. Determinism vs. non-determinism
>>  > > k. Solving the frame problem: monotonic solutions (explanation 
>> closure
>>  > > axioms; Reiter) vs. nonmonotonic solutions (using 
>> circumscription, or
>>  > > answer-set semantics, e.g. together with an appropriate 
>> formulation of
>>  > > the commonsense law of inertia)
>>  >
>>  > Note that a further distinction in the action languages you 
>> mention, is
>>  > that interia is not always implicit.
>>
>> Could you let me know what "interia" is? I googled, but that didn't help.
> 
> 
> basically frame axioms, ie that atoms (also called fluents in these 
> languages) keep there value if not affected by any action over a state 
> change. Intertia can be defined "per fluent" in some of these languages...
> 
>>  >As far as I remember, it is in
>>  > \cal{A}, but not in \cal{C} (or the related language \cal{K} which we
>>  > developed in Vienna during my thesis...)
>>  >
>>  > In that context, it would maybe also, even be worthwhile to look into
>>  > planning languages like PDDL.
>>  >   The PDDL work might by itself be interesting, since it is also 
>> kind of
>>  > a family of languages around a common core, where features can be
>>  > added/left out, maybe providing some inspiration for the extension
>>  > mechanism for dialects...
>>  >
>>  > Axel
>>
>> Axel, I think it would be very interesting to look at PDDL --- I agree 
>> that the way
>> it has been developed, over time, from a common core, could be a model
>> for how we develop methods for RIF's handling of different dialects 
>> (down the road).
>>
>> I will also look at \cal{K} --- thanks for the reference!
>>
>> In the meantime, however, as Chris and Sandro pointed out yesterday, I 
>> need
>> to refocus this work on RIF's short-term goals and the RIF Core. This 
>> means
>> less focus, at least in the short term, on many of the distinctions that
>> I've thus far put in the ontology, which are model-based and/or based on
>> the method of inference.
> 
> 
> fair enough.
> 
> best,
> axel
> 
>> Nevertheless, I agree with you that it's important for us, as we continue
>> in this work, to be aware of as many of the languages, systems, and 
>> issues that are out
>> there, as possible.
>>
>>  >
>>  > > l. All actions have preconditions and effects. Can also have failure
>>  > > conditions and success conditions. (Success conditions different 
>> than
>>  > > preconditions.)
>>  > >
>>  > > 4. The different features are sometime superficial, but may reflect
>>  > > different deep-seated foundational assumptions. Different sets of
>>  > > assumptions underlying these languages could make translation 
>> difficult.
>>  > >  Of importance is the growing set of results on methods of 
>> translations
>>  > > between various pairs of languages (e.g., between TAL and   sitcalc,
>>  > > fluent calc and various formalisms).
>>  > >
>>  > > 5. The exercise of constructing the ontology brought to light some
>>  > > interesting questions regarding the categorization of these 
>> features.
>>  > >  Does the distinction between single agents and multiple agents 
>> belong
>>  > > to the model or the theory? What about the distinction between the
>>  > > concurrency and asynchronicity? I’ve done a first effort 
>> at addressing
>>  > > these issues, but they remain open for discussion.
>>  > >
>>  > > Best regards,
>>  > > Leora
>>  >
>>  >
>>  > --
>>  > Dr. Axel Polleres
>>  > email: axel@polleres.net  url: http://www.polleres.net/
>>  >
>>  >
>>  >
>>  >
> 
> 
> 


-- 
Hassan Aït-Kaci  *  ILOG, Inc. - Product Division R&D
http://koala.ilog.fr/wiki/bin/view/Main/HassanAitKaci

Received on Wednesday, 25 April 2007 13:47:42 UTC