W3C home > Mailing lists > Public > public-xg-urw3@w3.org > September 2007

Re: RIF Working Group in a Nutshell

From: Jeff Z. Pan <jpan@csd.abdn.ac.uk>
Date: Mon, 10 Sep 2007 11:36:20 +0100
Message-ID: <46E51E24.9020604@csd.abdn.ac.uk>
To: Anne Cregan <annec@cse.unsw.edu.au>
CC: Giorgos Stoilos <gstoil@image.ece.ntua.gr>, public-xg-urw3@w3.org

Hi Anne and all,

It is true that RIF does not intend to be *the* Semantic We rule 
language; however, some widely used RIF dialect(s) will surely be 
regarded as (a) Semantic Web rule language(s). So far, it is unclear 
which dialect(s) will be the one(s) though.


Anne Cregan wrote:
> Giorgos,
> Thanks for that - I learnt something very important that I didn't 
> realise before.
> Are others as surprised as I am that RIF is ONLY going to be an 
> interchange
> format and is NOT attempting to build a language for writing Rules for 
> the Semantic Web?
> I think that for URW3 purposes, the ability to write rules will be 
> critical, so we
>  should keep a close eye on this.  Do we know of any working group 
> taking this on?
> Ken and Kathy - when you attend the W3C SemWeb Coordination Group
> conference call, could you perhaps ask them what work is afoot to support
> rule writing for the (semantic) Web?
> I would assume whatever we deliver would need this as a vehicle.
> Would others agree?
> Anne
> On 08/09/2007, at 4:23 PM, Giorgos Stoilos wrote:
>> Dear All,
>> During the August 1st telecon I promised to provide some feedback to the
>> group regarding the RIF Wroking Group (WG). Since it seems that I 
>> will also
>> miss some of the next telecons (both on the 19th and the 3rd it seems 
>> that I
>> will be travelling) I am sending a mail with some feedback.
>> ==ID==
>> - RIF stands for Rule Interchange Format.
>> - It is a Working Group (unlike our Interest Group), i.e. it will 
>> provide a
>> standard (W3C Recommendation).
>> - RIF is chartered for 2 years.
>> - RIF home page: http://www.w3.org/2005/rules/
>> - RIF Charter: http://www.w3.org/2005/rules/wg/charter.html
>> - RIF wiki page: http://www.w3.org/2005/rules/wg/wiki/FrontPage
>> == Objectives ==
>> RIF is the current action of W3C for the rules layer of Semantic Web. 
>> The
>> primary purpose is to propose a format for interchanging rules 
>> between rule
>> systems on the (Semantic) Web and *NOT* to create a W3C Rule Language 
>> for
>> the Semantic Web. Thus, one should not expect to use RIF to represent 
>> its
>> rules, i.e. creating a RIF Rule Base.
>> RIF is also expected to provide compatibility with current W3C 
>> Semantic Web
>> standards like RDF and OWL.
>> == Architecture ==
>> The work is split in to 2 phases:
>> In phase 1 we will defined a RIF Core language which is lets say "a 
>> minimum
>> *interesting* fragment that is common over most logic programming 
>> languages
>> and systems". Then in phase 2 several RIF Dialects will extend or 
>> restrict
>> the semantics and functionality of RIF Core elements to create a rule
>> interchange format for an LP language not supported by RIF Core. 
>> Examples of
>> RIF Dialects could be an F-Logic Dialect, a DisjunctiveDatalog 
>> Dialect, a
>> Horn+Negation, a Production Rule dialect, etc.
>> So if you wanted to exchange rules between your Disjunctive Datalog 
>> system
>> and some other one (also a Disjunctive Datalog system) you would have to
>> implement a mapping from your rule base to the appropriate RIF 
>> Dialect and
>> of course the other part should also be able to translate the RIF 
>> Rules to
>> its own format.
>> Maybe the group will examine some cases of exchanging rules between 
>> diverse
>> systems, i.e. a RIF StableNegationToWellFoundedNegation Dialect but 
>> is only
>> expected to do it for cases that such mapping has been studied in the
>> literature and not do research on its own.
>> Checkout: http://www.w3.org/2005/rules/wg/wiki/Arch/Extensibility
>> == So Far ==
>> The group started with UseCases & Requirements and until then it has
>> produced 3 versions of them. The working version is here
>> http://www.w3.org/2005/rules/wg/wiki/UCR.
>> Currently the work is focused on RIF Core 
>> http://www.w3.org/TR/rif-core/,
>> its XML syntax, RDF Compatibility and build-ins. Originally RIF Core was
>> proposed to be Horn Logic + Sorts, but we have backtracked to Horn
>> http://www.w3.org/2005/rules/wg/wiki/Core.
>> Regarding dialects there was some work on a NegationDialect and some
>> Prodcution Rule System dialect but I think little has been done on this
>> issue.
>> == RIF and Uncertainty ==
>> Since the beginning we (the NTUA-IVML group) have tried to bring up the
>> issue of uncertainty extensions of Semantic Web standards whenever 
>> possible.
>> Initially, we succeeded in having "uncertainty" mentioned in the RIF 
>> Charter
>> under the RIF Extensibility section
>> http://www.w3.org/2005/rules/wg/charter#extensibility.
>> Then during the UseCases work we added a UC for Fuzzy
>> http://www.w3.org/2005/rules/wg/wiki/Fuzzy_Reasoning_with_Brain_Anatomical_S 
>> tructures but it didn't made it into the UCs document. Nevertheless, we
>> tried to add it implicitly through the Medical Decision support Use Case
>> http://www.w3.org/2005/rules/wg/wiki/UCR/Ruleset_Integration_for_Medical_Dec 
>> ision_Support that exists in it.
>> As with the UseCases it seems that we could propose an Uncertainty 
>> Dialect
>> to the RIF group. Actually together with Carlos Damasio, Jeff Pan and
>> Umberto Straccia we have already done some work for an Uncertainty RIF
>> dialect in a paper to appear in Fundamenta Informaticae.
>> But on the other hand from my experience in related W3C activities I 
>> would
>> say that it is unlike that such an extension will survive as a 
>> dialect in
>> the final standard. Uncertainty always looks kind of exotic to most 
>> people,
>> while several ones in RIF would definitely eagerly object having them 
>> as a
>> RIF Dialect. On the other hand even neutral people would prefer to see a
>> dialect covering their favourite or some popular system rather than
>> uncertainty if it gets to choosing among "n" for standardization. 
>> Moreover,
>> as far as I know, the issue of uncertainty LP is not such mature in the
>> sense that there are not so many uncertainty rule bases and systems out
>> there that one would like to interchange between them. So our case is
>> generally weak.
>> Currently, it is not decided how many and which dialects would the group
>> create as well as the requirements for Phase 2
>> http://www.w3.org/2005/rules/wg/wiki/Design_Constraints, where 
>> uncertainty
>> is included, have not been discussed yet.
>> Hope I was concise enough. I also welcome any related questions.
>> Greetings,
>> -gstoil
Received on Monday, 10 September 2007 10:37:34 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 19:50:54 UTC