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

Hassan Aït-Kaci wrote:
> 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.


indeed! (I just saw that I also typoed it in my reply, sorry)

axel

> 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/

>>>  >
>>>  >
>>>  >
>>>  >
>>
>>
>>
>>
> 
> 


-- 
Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/

Received on Wednesday, 25 April 2007 14:01:50 UTC