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[protege-owl] Modeling change, source, uncertainty, contradiction?

Matt Williams matthew.williams at
Wed Aug 22 07:36:11 PDT 2007

This looks more like RDF reification.

You may have more luck looking at something like Jena.


Johann Petrak wrote:
> Matt Williams wrote:
>> As a very simple approach to modelling time, you could use 
>> time-interval-valid versions of the ontology. Not pretty, but might be 
>> enough.
> For my purpose, I would be more interested in searchability than
> deductability. In other words, I do not want to make deductions based
> on time -- it would be sufficient to find properties of instances
>  that are valid at a specific time. (So time would not be an issue
> for classes, just for instances)
> Naively I want an attribute "valid during" for each property/relation
> between instances.
> More generically I want several attributs: "valid during", "source"
> etc.
> The only thing I would need to do is to get the value of these
> attributes out of the knowledge base and to search for triples
> where these attributes match a specific pattern.
>> DL ontologies will not handle conflicting information. To do that, you 
>> need to use a defeasible formalism. There is a little bit of work on 
>> ontologies & defeasibel reasoning.
>> I have used argumentation & ontologies; there's a paper at 
>> which also has 
>> references to the other approaches.
> Thank you for the reference. I am not sure I need it at such a
> complex level though, since I do not need a reasoner to
> come up with sets of entailed or conflicting facts.
> I think it would be sufficient for me to be able to model
> something like
>   "source A indicates instanceX Rel1 instanceY"
>   "source B indicates instanceX notRel1 instanceY"
> or put differently
>   instanceX Rel1-withattr: from source A instanceY
> etc.
> So it comes down to attatching searchable arbitrary attributes
> to properties/relations again.
> Could it be that I am missing something totally elementary
> here because it seems that should be something that is needed
> all the time?
> Cheers,
>   Johann
>> If you want to discuss this in more detail, email me off-list.
>> HTH,
>> Matt
>> Johann Petrak wrote:
>>> I am pretty new to using Ontologies for knowledge represenation so
>>> most of the tutorials and examples I have seen only are about
>>> modeling some consistent set of unchanging facts.
>>> However, in real word situations it is often necessary to deal
>>> with knowledge or information that has one of the following
>>> complications:
>>> * a fact might change over time. More exactly, a property
>>>   might be valid during some period of time but not another.
>>>   Is it possible to model this in OWL ontologies and if yes,
>>>   what are common design patterns to do it?
>>> * The fact that some instance has some property might be
>>>   known based on sources A and B but might not be confirmed
>>>   from source C. More problematic, it might contradict
>>>   information from source D. So instead of some fact just
>>>   "existing" we would like to model that it exists
>>>   "according to source A" but "not confirmed by source C"
>>>   and "not, according to source D"
>>>   Is it possible to model this?
>>> * Sometimes it would be useful to attach a level of belief
>>>   to a fact. E.g. some instance having some property might
>>>   be likely but not certain.
>>> These things are probably differently hard to model, if at
>>> all.
>>> My biggest concern at the moment is change over time: for
>>> most applications where I need some knowledge representation
>>> it would be extremely important to be able to know that
>>> e.g. some name was used during a certain time or that some
>>> property existed during a certain period but not another.
>>> I would be thankful for any hints you could give me or
>>> any papers or sources you could point out where these
>>> issues are discussed.
>>> Johann
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