[expertfinder-dev] Re: Expertise and Trust Vocabs

[Axel Polleres]

Reto Krummenacher wrote:
>>My point is that these numbers are usually arbitrary (ok, maybe for the
>>particular example with the trains, they could be backed by some
>>statistics). If you can convincingly tell me how you'd guess the number
>>for  "I trust Reto by 73.456% that he knows about RDF", I'd be happy to
>>know... (Do you keep a personal statistics on how often your friends say
>>nonense about a specific topic and keep this up-to-date? :-) )
>>Seriously, I am just not sure how to arrive at such values in a useful
>>manner. That's why I said, either saying yes or no
>>could be good enough for getting a start.
> 
> 
> sure.
> 
> 
>>>anyway, also of what i remember from my security classes at
>>>university, there
>>>are trust evaluation algorithms that are based on the combination of
>>>trust
>>>values from different parties, arent there?
>>
>>Not aware, maybe Daniel could post some relevant pointers?
>>
>>anyway, my claim was that the numeric values seem to be arbitrary and
>>hard to assess and I was suggesting to start simple.
>> Also other wider used vocabs have some arguable properties in favor of
>>keeping things simple than being over-precice. Take for instance:
>>
>>  foaf:based_near
> 
> 
> this example might be unhappily chosen, as based_near calls not only upon trust
> of information, but rather a lot of interpretation.
> 
> if i say near innsbruck, i mean up to may be 50km away. my friends in sweden
> refer to nearby when considering distances around 200km. where is the trust
> value now?

That wasn't an example for trust, but that meta_data might be 
deliberately imprecice just to get 80% of the use cases right and not 
every single application. See the next sentence...


>>In fact this also should be rather a ternary relation which also gives
>>the time range (since) when a person was/is based near a certain
>>location, but it seems a simple and possibly incomplete way to represent
>>information was chosen dliberately here.
>>
>>I'd at least guess we should have means for both, a very simple and a
>>more fine-grained vocabulary.
> 
> and even if you start taking about digital-trust (i.e 1 or 0) you will soon get
> into non-digital trust values anyway. what about cases where you have
> contradicting information about the statement you consider. lets say 6 guys
> support the truth value of your statement with trust 1, while other 3 contradict
> it (i.e. truth value 0). what is now the trust you give your statement?

I was really thinking of something simpler here...
ie. if e.g. many people say they think you are an expert in RDF, then 
this would be ranked higher, anyway, all this is subject to an 
algorithm, this depends on the application, e.g. something like pagerank 
could be a basis here, but I see this as a separate issue from the 
meta-data itself.

axel


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