Production Rule Representation Team Response

Presentation to BEIDTFOMG Montreal Aug 2004

Ruleml.org

Agenda

Introduction to PRR

Introduction to PRR Team

PRR Scope, Goals, Requirements

PRR Positioning & Other Standards

What is a Production Rule?

• A statement of programming logic that specifies the execution of one or more actions in the case that its conditions are satisfied.– If Conditions then Actions– Executed by an inference engine

• NOT what is meant in OMG model transformations

Why a PRR Standard?• Production Rules & Inference Engines are used in

industry as a means of– Efficiently representing and executing business rules– 100Ks – Ms of such rules in use across different

organizations– Used in decision automation in financial svcs, government,

insurance, healthcare etc

• Issues in PRR implementations include– How do I represent rules in my UML model?– How do I guarantee vendor neutrality in rule representation?

• Lack of standard results in– Rules being omitted from models– Rules being integrated into UML incorrectly– No rule exchange standards– No standardized training for modelers

State of the Technology• Inferencing with Production Rules: 20 years old

– Backward chaining and forward chaining are well established technologies

• Vendors in the industry– Commercial inference engines

• Fair Isaac: Blaze Advisor• ILOG: JRules• CA: Aion

– Open source / source-available tools• JESS• DROOLS

– More in development

PRR Team Members

• IBM: largest IT services and tools company

• Fair Isaac:

• Ilog:

• LibRT: vendor of rule verification technology

• RuleML: existing rule standards body

the Top 2 Suppliers of inference engines & rule management technology

PRR Scope

• MDA Platform Independent Model: an “Inferencing platform” that is independent of specific inferencing product

• Excludes – Logic programming and unification– Constraint programming and constraint

satisfaction– Event-Condition-Action (ECA) rules– Fuzzy rules and Bayesian inferencing

PRR Team Goals• Opportunity for PRR standard that satisfies

both OMG and RuleML.org needs• Provides basis for rule interoperability &

encourage further adoption of production rules in software systems

• Standardize the representation of rules within common UML diagrams

NOTE: At this time, we are NOT concerned withtheoretical MDA transformations

to/from other metamodelsHOWEVER: We do not preclude this capability

being provided outside of this standard

PRR Requirements• MOF 2.0 compliant Production Rule Metamodel

– Abstract syntax for representing PR in UML models– Supports “patterns” across Conditions and Actions

• Supported inferencing algorithms– Forward or backward chaining– Support for Rete algorithm is required

• XML Schema for XMI support• Rulesets

– Properties: reasoning mode, identifier– Ruleset aggregation– Association with UML Activity Diagram

• Rule/ruleset naming• Examples

PRR in UML

Re-use existing UML languages as much as possible, withminimum extensions / changes required to achieve a PRR

Conditions: OCL subset against a defined object model+ extensions to support patterns+ extensions to support variable / pattern sharing with actions- OR -

RuleML constructs

Actions: Action Language subset against a defined object model+ extended to support scope defined through conditions’ context

Metamodel of Rules

DerivationRule ReactionRuleIntegrityRule

SQL:1999Assertion

ProductionRule

ECARule

SQL:1999 Trigger

SQL:1999 View

OCL 2.0 Invariant

XSB 2.6 PrologRule Jess 3.4 Rule

ECAPRule

TransformationRule

XSL 1.0 RulePIM

MS Outlook 6 Rule

PSMOracle 10gSQL View

ILOG JRule BlazeAdvisorRule

Rule

Possibly also consider “Procedural Rules”

Metamodel under development

Investigating basics of representation structureas well as effects of OCL and AS; extended for rule scope

name[1] : string

ProductionRule1

condition1..*

1

producedAction1..*

{ordered}

ActionExpressionLogicalFormula

name : string

ProductionRule

ActionExpressionLogicalFormula

+parentRule

1

+producedAction1..*

-parentRule

1

-condition1..*

Use of association:this means conditions and actions arerepresented independently.Useful if conditions and actions- have independent scope,- can be shared.

Use of composition:this means conditions and actions arerepresented within rules.Useful if conditions and actions- are dependent on rule contexteg action depends on condition context for pattern,- should be repeated rather than shared.

Comparison with Existing Stds

JavaInvocation

JSR-094

Desire to includestandard

rule transportas well asinvocation

W3C / XML

XPath etc

Need for

specificproduction rulerepresentation

RuleML

Predicate-logic

Requirementfor more

commercial usageEg OORuleML

separatesrules from data

PRR positioningin MDA for Current Tools

CIM

PIM

PSM

Execution layer

Fair Isaac& IlogRule MgmtTechnology

IBMTools

andSolutions

thatdefine,embed

productionrules

LibRTRule

TestingTechnology

PRR

PRR positioningin MDA for BEIDTF Models

CIM

PIM

PSM

Execution layer

BPDMBSBR*Rule & ProcessModels

Business Metamodel

Business Object Model

PRR

BSBR Vocabulary

PRR positioningin MDA for BEIDTF Models

CIM

PIM

PSM

Execution layer

BPDMBSBR*Rule & ProcessModels

Business Metamodel

Business Object Model

PRR

BSBR Vocabulary

Appropriate engines / code generators

PRR Issues

• Is PRR still useful, given BSBR defines formal rules at business level?

• Will transformations be automatable? Or just traceable?

• Is OMG Metamodel structure too heavyweight?

POSSIBLY: BSBR is an information model; not targeted at implementation of services

UNKNOWN: Depends on customerinterest. Note lack of success of CASE…

POSSIBLY: Could derivea lightweight version in future

PRR Issues (2)

• Will RuleML be coverable in same standard?

Use/extend of BOTH OCL & ASL? Why not extend just 1?

PROBABLY: Working on examplesto verify this assumption

POSSIBLY: Might be that extensionsare useful for other rules / uses in OMG?

Status & Summary

• Effective PRR team in place• Current work:

– Expanding metamodel to accommodate RFP requirements

– Exploration of OCL + AL to provide behavior– Example-driven investigations comparing

RuleML, LibRT RBML, Ilog + Fair Isaac rule implementations, and OCL + AL definitions

• Next: Diagramming PR• Next Update: Nov mtg