Rules

1
CmpE 583- Web Semantics Theory and
PracticeRULES RULE MARKUP

• Atilla ELÇI
• Computer Engineering Department
• Eastern Mediterranean University

2
Introduction

• On top of ontologies layer there rests rules
  layer in the semantic Web protocol stack.
• Rules are of differing nature / purpose (the rule
  spectrum)
• Derivation rules
• Transformation rules
• Reaction rules
• Rules serve to
• Specify queries and inferences in Web ontologies,
• Mappings between Web ontologies, and
• Dynamic Web behaviors of workflows, services, and
  agents.
• Rules can be stated in natural language, some
  formal notation, or in a combination of both.

3
Agenda

• Rules facts
• RuleML (Rule Markup Language)
• Ontology rule languages like the Semantic Web
  Rule Language (SWRL), which combine RuleML with
  OWL.
• Rule Interchange Format initiative at W3C.

4
Rules Facts TBL-1998

• The Semantic Web is a universal space for
  anything which can be expressed in classical
  logic. (NB try reverse this sentence
  implication is anything of classical logic is in
  the Semantic web!).
• Many knowledge representation systems exist. All
  distinguish data and rules
• Data pool of info expressed in a simple
  language (NB but not in a natural language).
• Rules
• Control the inference steps
• Written in a restricted language (NB so to
  maintain computability)
• Aim at preserving computability.
• Conveys two separate pieces of info
• Classic logic fact (NB as embedded in the rule
  system)
• Deduced-implied finding (NB that is, append all
  rules as extracted from fact documentation and
  their implication).
• The Semantic Web uses the classical logic.
• Inconsistent data is tolerated because trust is
  based on verified reputation of the source. (NB
  Every document has its truth system user
  consumes that whose creator/conveyor he/she knows
  as reputable and trusts).

5
RuleML docs RuleML Homesite

• Rules can be stated in natural language, in some
  formal notation, or in a combination of both.
• Being in the 'semiformal' category, the RuleML
  Initiative is working towards an XML-based markup
  language that permits Web-based rule storage,
  interchange, retrieval, and firing/application.
• RuleML covers the entire rule spectrum, from
  derivation rules to transformation rules to
  reaction rules. RuleML can thus specify queries
  and inferences in Web ontologies, mappings
  between Web ontologies, and dynamic Web behaviors
  of workflows, services, and agents.
• Aiming for business intelligence, AI?
• Harold Boley RuleML Initial Steps, Version 1.0.
  2002-08-22.
• Harold Boley, Benjamin Grosof, Michael Sintek,
  Said Tabet, Gerd Wagner RuleML Design, Version
  0.8. 2002-09-03.

6
RuleML presentations

• By Benjamin N. Grosof and Harold Boley
• "Introduction to RuleML", slides of
  teleconference talk (in pdf).
• "Part 2 of 2 Additional Optional Slides" (in
  pdf).
• "RuleML Intro Examples and More Syntax Details".
• The RuleML Tutorial.

7
Rule Layer Work

• Rule Interchange Format initiative at W3C
• See the charter
• Especially the RIF Use Cases and Requirements
  document.
• RuleML Initiative vied to merge with DAML, OASIS,
  W3C, or US/EU Joint Committee (JC) in search of a
  home base some years ago. Still independent!
• In effect, JC merged with DAML and later DAMLOIL
  merged with W3C. So now, OASIS, W3C RuleML
  Initiative are still going their separate ways.

8
Five Publications from RIF-WG of W3C

• The Rule Interchange Format (RIF) Working Group
  published five new Working Drafts today. Since
  the Last Call Working Draft of RIF Basic Logic
  Dialect (BLD), the group has been developing
  other key dialects, components, and test cases.
  The new publications are
• RIF Use Cases and Requirements minor changes
• RIF Core new design to support both BLD and PRD
• RIF Datatypes and Built-Ins 1.0 various
  improvements
• RIF Production Rule Dialect (PRD) operational
  semantics are complete
• RIF Test Cases early stages of test suite
• The Working Group is nearing Last Call on these
  remaining elements of RIF, and welcomes feedback
  from rulesystem users and designers. Please send
  comments by 23 January. Learn more about the
  Semantic Web Activity. Dated 2008-12-19

9
Where to Get More Information?

• TBL-1998 TBL Axioms of Web Architecture Rules
  and facts Inference Engines vs. Web. In Design
  issues.
• RuleML Homesite The Rule Markup Initiative
  http//www.ruleML.org/