[rdfweb-dev] foaf thoughts

Fri Jul 18 17:15:10 UTC 2003

At 19:00 18/07/03 +0200, Flo Ledermann wrote:
>graham, thanks for these pointers. unfortunately the first host seems to 
>be down, i tried again today but no luck there.

They do seem to be a bit up-and-down, at times.  I just checked and they're 
accessible.  I can only suggest... keep trying.

>josangs stuff i found very interesting as a basis for trust calculations. 
>although, as i said, i do not really believe that a subjective rating of 
>trust on any scale is a good idea, the subjective logic approach might be 
>useful.

I share your skepticism, but it seems to be a well-liked approach.  And I 
expect it will find use in local domains where simp[lifying assumptions can 
be applied, even if it's not fully scalable.

#g
--

>Graham Klyne wrote:
>>You might find this of some interest:
>>   http://www.itrust.uoc.gr/
>>Also, there has been some work on modelling of trust using subjective 
>>logic, where work by Josang seems to be oft-cited; cf.
>>   http://security.dstc.edu.au/staff/ajosang/
>>There's also a more application-oriented resource guide here:
>>   http://www.wiwiss.fu-berlin.de/suhl/bizer/SWTSGuide/
>>#g
>>--
>>At 13:50 17/07/03 +0200, Flo Ledermann wrote:
>>
>>>hi all, i am new to the FOAF world but already fascinated...
>>>
>>>i am carrying this project around in my brain for a long time already, 
>>>circulating around friendship networks, resource sharing, collaborative 
>>>filtering and the like, and i already had some prototypes implemented 
>>>over the years. but now i came across foaf and i think it is really 
>>>answering a lot of open questions to me...
>>>
>>>however, some questions still remain open, and some new emerged, and 
>>>after i read through the whole archive of rdfweb-dev yesterday, i dare 
>>>to discuss them with you:
>>>
>>>the basic motivation for me is that i think a lot of resources (in the 
>>>real world) are wasted because of a lack of communication and trust 
>>>between the individuals - flats are empty, cars are unused or used with 
>>>only one person sitting in there, mp3 collections are maintained 
>>>individually, knowledge is not used or has to be acquired from 
>>>centralized, "official" sources (like google) and so on. as far as real 
>>>life is concerned, there are established means and procedures to 
>>>exchange these resources, either in public (via a "market") or in 
>>>private (via friends that i "trust"), but for the infosphere we lack 
>>>these established standards.
>>>
>>>ok, so far i think i've just written a basic introduction to the foaf 
>>>ideas :). now for the concrete questions:
>>>
>>>- concerning real life resources, these can currently not be expressed 
>>>in foaf in every details. do i just take any ontology i come across, to 
>>>describe, for example, that i "own" a "car" that i might "lend" to 
>>>anyone who i "trust" with a maximum degree of 2 (i.e. a friend or a 
>>>friend-of-a-friend)? concerning the things itself, i think this is not a 
>>>problem and even intended like this by rdf and namespaces, but the 
>>>abstract concepts like "trust", "resource", "lending" etc. should maybe 
>>>go into the foaf core.
>>>
>>>- which leads to the definition of "trust", which has been a topic in 
>>>this community from the start, as far as i can tell from the archives. 
>>>i've read jennifer goldbeck's paper, and i don't think that i would want 
>>>to rate the degree of friendship or trust that i have towards a person 
>>>on any scale - i think we have to find other ways to enable the user to 
>>>express and control these things, and to enable the software agents 
>>>acting on behalf of our users to draw the right conclusions from the 
>>>rdfweb they are spidering. before i came across foaf, i decided (after 
>>>many iterations and discussions of the topic) that i would want to have 
>>>two basic relationship types, "knows" and "trusts", without any further 
>>>specification or quantification (of course that can always be layered on 
>>>top of that). i think with these two relationships we could go a long 
>>>way, because i would have some way for rapidly extending my personal 
>>>network with people i know, without giving away too much control and 
>>>still connecting to my friends (the people i trust) in a tighter way.
>>>
>>>- for querying and using the network, this would give quite powerful 
>>>capabilities. things like "ask all people i know and who live in my town 
>>>whether they have a welding machine" or "allow all people i trust to a 
>>>degree of two or less to download mp3s from me" are then possible. but 
>>>how do i formulate these queries (for now, on a technical level rather 
>>>than a ui level)? is there any rdf query language that can perform these 
>>>kind of tasks?
>>>
>>>- now comes a hard one: in the real world, i give out different 
>>>information depending on who is talking to me. a friend knows a lot 
>>>about me (including address, resources, but also personal details, 
>>>interests etc.), whereas towards a strangr i might be more careful with 
>>>giving out information or i might even lie to him/her! how do we model 
>>>that in rdf/foaf? i know this has been discussed on the list, but for me 
>>>no conceptual solution was ever presented. i don't like the 
>>>cryptographic approaches that have been discussed, because they might 
>>>ensure integrity of the information, but i am more interested in this on 
>>>a conceptual level - how do we want this to work? i think the 
>>>cryptographic approaches are just not fine-grained enough to solve this.
>>>
>>>first of all, we have to find some way of describing these constraints 
>>>in foaf - which parts of my foaf file are given out to whom. to do that, 
>>>one would need a kind of pattern language, and persons/agents matching 
>>>the patterns (similar to a query, but a kind of ex-post query) would 
>>>receive the information. on an implementation level, we would have to 
>>>move away from openly published foaf files, and put them behind a kind 
>>>of "firewall" (which i would maybe call "skin") to protect the personal 
>>>information and only give out the information that i want the other 
>>>agent to receive. this would require some kind of 
>>>authentication/identification mechanism ("i am an agent asking in behalf 
>>>of this person for that information"), but could still be realized in http.
>>>
>>>the major implication of such a feature would be that it requires more 
>>>infrastructure to set it up - at least a webserver that you can control 
>>>and script to a certain amount - and would therefore go away a bit from 
>>>the grassroots p2p approach that is possible now. on the other hand - it 
>>>is just an optional enhancement, and people could still publish thier 
>>>public info through static rdf files, as they do now.
>>>
>>>of course one would then use cryptographic approaches to ensure the 
>>>integrity of authentifications and so on, but i am not interested in 
>>>cryptography and could personally live with potential misuse, in a 
>>>prototype phase. but i am sure there are people out there who can solve 
>>>these problems.
>>>
>>>
>>>- finally, a few usecases i am interested in, and i would be happy to 
>>>contribute to foaf and the surrounding tools to be able to realize them:
>>>
>>>+ collaborative filtering/forwarding of messages through my foaf network
>>>+ mp3/movie recommendations (and maybe sharing, but that would require 
>>>additional software installed at the users machine, which at this point 
>>>probably goes too far.)
>>>+ car sharing and "who can give me a ride" service
>>>+ resource sharing (tools, space, knowledge)
>>>
>>>ah, btw you can have a look at a system i started to develop (a kind of 
>>>proprietary foaf) at http://architekt.ims.tuwien.ac.at/map/map.php - 
>>>it's defunct at the moment (transitioning to foaf ;), but you can take 
>>>it as a proof for my commitment/skills if you want :) ah, and the "new 
>>>entity" dhtml form might be handy for the foaf-o-matic, i am especially 
>>>proud of the expandable "connections" list. not sure if this works 
>>>outside mozilla though.
>>>
>>>phew, pretty long mail, nevertheless hoping for feedback...
>>>
>>>all the best,
>>>
>>>f/0
>>>
>>>http://www.mediavirus.org/f/0/foaf.rdf
>>>
>>>--
>>>|-
>>>| Florian Ledermann <ledermann at ims.tuwien.ac.at>
>>>| http://www.mediavirus.org/f/0/
>>>|-
>>>| "I think I'm thinking, therefore I possibly are."
>>>|-
>>>
>>>
>>>
>>>_______________________________________________
>>>rdfweb-dev mailing list
>>>rdfweb-dev at vapours.rdfweb.org
>>>wiki: http://rdfweb.org/topic/FoafProject
>>>http://rdfweb.org/mailman/listinfo/rdfweb-dev
>>
>>-------------------
>>Graham Klyne
>><GK at NineByNine.org>
>>PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
>
>--
>|-
>| Florian Ledermann <ledermann at ims.tuwien.ac.at>
>| http://www.ims.tuwien.ac.at/~flo/
>|-
>| TU Wien - Vienna University of Technology
>| Interactive Media Systems Group
>| Favoritenstrasse 9-11/188/2
>| A-1040 Vienna, Austria
>|-
>| "I think I'm thinking, therefore I possibly are."
>|-
>
>
>
>_______________________________________________
>rdfweb-dev mailing list
>rdfweb-dev at vapours.rdfweb.org
>wiki: http://rdfweb.org/topic/FoafProject
>http://rdfweb.org/mailman/listinfo/rdfweb-dev

-------------------
Graham Klyne
<GK at NineByNine.org>
PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E