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

Re: RIF Working Group in a Nutshell

From: Ken Laskey <klaskey@mitre.org>
Date: Mon, 10 Sep 2007 00:14:32 -0400
Message-Id: <F962AE17-8C94-4625-9773-C5FD9BEAFC9E@mitre.org>
Cc: Giorgos Stoilos <gstoil@image.ece.ntua.gr>, <public-xg-urw3@w3.org>
To: Anne Cregan <annec@cse.unsw.edu.au>

The intent of RIF is to avoid choosing the winner among possible  
rules formats and to theoretically come up with a way of exchanging  
information across formats.  There was always the question of whether  
one could write the interchange format without effectively writing a  
new rules language.

URW3 is modeled with the idea behind RIF in mind to see if we can  
"interchange" uncertainty information without (or at least  
minimizing) making things specific to an uncertainty methodology.   
The answer is far from obvious.

As for whether there can be an uncertainty dialect for RIF, our  
challenge is to identify what would be in such a dialect.  I hope RIF  
provides a Dialect Framework to which others could develop specific  
dialects.  In that case, there would be less pressure on the scarce  
resources of a single WG.

Still, the current XG will not develop a Dialect because
(1) we have yet to establish what would go into such a dialect
(2) RIF hasn't sufficiently defined a dialect framework
(3) we aren't chartered to develop a dialect (but a future group might)

Other thoughts?


On Sep 9, 2007, at 11:39 PM, 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

Ken Laskey
MITRE Corporation, M/S H305      phone: 703-983-7934
7151 Colshire Drive                         fax:       703-983-1379
McLean VA 22102-7508

Received on Monday, 10 September 2007 04:14:49 UTC

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