[Attempto] Source Code of RACE reasoner

[Huan Nguyen]

Thanks Dr. Fuchs,

I planned to use propositional phrases to express temporality as well.
However, I'm in the process of investigation on how many types of
requirements I can express with the current ACE. If the results are not
good, then I will need to reintroduce temporal operators + "before, after,
until, always..." into ACE (I'm quite interested in this task as well).

In case I need to modify the APE parser, is there any way that I can have
access to kind of APE documentation which supports the development process?

Kind regards,

Huan


>
> On Sat, Sep 22, 2012 at 9:39 PM, Norbert E. Fuchs <fuchs at ifi.uzh.ch>wrote:
>
>>
>> On 21 Sep 2012, at 15:24 , Huan Nguyen wrote:
>>
>> > I am just so curious that whether you have any plan to extend ACE with
>> temporal operators (which supported by temporal logics)? currently I think
>> this is the only considerable limitation of this cool language.
>>
>> Dear Huan
>>
>> I take the liberty to send this message also to the Attempto mailing list.
>>
>> In earlier implementations of ACE we had times, events and states. Citing
>> for example from our earliest publication
>>
>> N. E. Fuchs, R. Schwitter. Specifying Logic Programs in Controlled
>> Natural Language, Proceedings CLNLP 95, ELSNET/COMPULOG-NET/EAGLES Workshop
>> on Computational Logic for Natural Language Processing, University of
>> Edinburgh, April 1995.
>>
>> > DRT with Eventualities (DRT-E)
>> >
>> > DRT-E investigates further details of the semantics of verbs, taking
>> into account the theory of underlying eventualities (events or states) and
>> handling temporal and aspectual information [Kamp & Reyle 93, Reichenbach
>> 47]. A prototypical implementation of DRT-E is described in [Brown 94].
>> >
>> > Investigating sentences like
>> >
>> >      The customer enters the card.
>> >      SimpleMat checks the card.
>> >
>> > and
>> >
>> > Every customer has a personal code.
>> >
>> > we recognise that the first two sentences are naturally understood as a
>> report of temporally ordered events, while the second sentence describes
>> something like a condition or state.
>> >
>> > Verbs like enter or check introduce the existence of an event in much
>> the same way as a noun phrase introduces the existence of an object. Events
>> involve some kind of change in the universe of discourse, they persist
>> through a certain interval of time and come eventually to a culmination
>> point. They imply that some non-temporal condition, which is true when the
>> event starts, is terminated by the event, and is replaced by further events.
>> >
>> > States differ from events. A state verb such as have expresses a
>> quality that is true indefinitely – it involves the continuation of a
>> condition.
>> >
>> > Sometimes the distinction between state-sentences and event-sentences
>> is recognisable from the syntactic form of the verb, but it is well known
>> that it is not the verb alone which decides about the eventuality
>> introduced by a new sentence. The different thematic roles may exert a
>> major influence.
>> >
>> > In our approach, we represent the statement that E1 is the event of X1
>> entering X2 as enter(E1,X1,X2) and use the special predicate cul(E1,T1) to
>> express that the event E1 culminates at time T1. The relation between the
>> reference time T1 of E1 and the speech time N is established with the help
>> of the additional predicate at(T1,N). With these notational changes, the
>> DRS looks like
>> >
>> > N E1 T1 X1 X2 E2 T2 X3 X4
>> > customer(X1)
>> > card(X2)
>> > enter(E1,X1,X2)
>> > cul(E1,T1)
>> > at(T1,N)
>> > named(X3,simplemat)
>> > card(X4)
>> > check(E2,X3,X4)
>> > X4 = X2
>> > cul(E2,T2) at(T2,N)
>> >
>> > As mentioned above, a state is temporally extended and homogenous. It
>> describes a static situation S that holds or does not hold at a given time
>> T. The function of the verb have is twofold: it introduces a discourse
>> referent S which represents a state of affair and it provides a descriptive
>> characterisation of this state represented by S. We will retain this
>> information as a predicate of the form have(S,X1,X2). The additional
>> predicate hold(S,T) asserts that S holds at T and the condition at(T,N)
>> indicates that the eventuality described is located at the same time as the
>> utterance time of the discourse that the DRS is taken to represent.
>> >
>> > X1
>> > customer(X1)
>> > =>
>> > N S T X2
>> > personal_code(X2)
>> > have(S,X1,X2)
>> > hold(S,T)
>> > at(T,N)
>>
>> For some time we even considered introducing temporal operators like
>> "before", "after" and "while", but we never did for two reasons: first,
>> classifying verbs as event or state is not easy – see above citation – and
>> second, the development of ACE and its tools was often driven by the
>> projects we were involved in – in recent years the semantic web where there
>> is no need for temporality. Thus at some time we decided to remove times,
>> events and states from the language, concretely from the DRS representation
>> derived from ACE texts, and we simplified the ACE parser accordingly. We
>> have no plans to reintroduce these features.
>>
>> Now you have two possibilities: First, reintroduce yourself temporality
>> into ACE and the DRS language and modify the ACE parsing engine APE
>> accordingly. Second, use prepositional phrases to express temporality which
>> was done years ago in an Israelian project for signal processing. Here is a
>> modification of the above example
>>
>> A customer enters a card at a time T1.
>> SimpleMat checks the card at a time T2 and T2>T1.
>>
>> Best regards.
>>
>>    --- nef
>
>
>
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