SweetDeal: Representing Agent Contracts With Exceptions using XML Rules, Ontologies, and Process Descriptions

tags
Rules as Code Benjamin Grosof

Notes

Abstract

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SweetDeal is a rule-based approach to representation of business contracts

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builds upon the situated courteous logic programs knowl- edge representation in RuleML

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process knowledge descriptions whose ontologies are represented in DAML+OIL

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process ontology knowledge from the MIT Process Handbook

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1. INTRODUCTION

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automates (parts or all of) such business contracts by repre- senting and communicating them as modular sets of declarative logic-program rules.

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2. OVERVIEW OF THE REST OF THE PAPER

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3. SWEETDEAL, RULEML, and SWEETRULES: MORE BACKGROUND

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Contracts are represented using interoperable rules in XML. Declarative logic pro- grams (LP) are the fundamental knowledge representation (KR) in which these rules are expressed.

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Rules represent part or all of an overall contract.

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Modification of a contract rulebase can be performed modularly during negotiation or completion

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Procedural attachments in the rules are used to perform external actions or queries

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advantages of the SweetDeal approach. What are the compet- ing approaches to representing contracts?

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SweetDeal is fairly unique in being rule-based, and quite unique in using SCLP

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Rules (vs. general code) provide a relatively high level of conceptual abstraction.

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Rules are especially good for specifying contingent provisions

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One may automatically reason about the contract/proposal by performing inferencing in the rule KR, for which computational tractability guarantees are available

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One may modify modularly, and thus relatively easily, the contract provisions: using prioritized defaults and rule modules

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SweetRules enables bi-directional translation from SCLP RuleML

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The SCLP case of RuleML is expressively powerful.

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the design of SCLP as a knowledge representation (KR) grew out of a detailed requirements analysis [1] for rules in automated contracts and business policies.

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The SCLP KR has fairly attractive worst-case computational complexity

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The complexity, and scaleability, of Datalog SCLP KR is thus not much worse than that of SQL databases

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(SC)LP (i.e., RuleML) has one main expressive limitation, as compared to First Order Logic (FOL) – or to Description Logic: in LP one cannot conclude a disjunction (nor an existential).

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FOL lacks nonmonotonicity

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FOL lacks procedural attachments

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although Epilog has operations, at least

4. MIT PROCESS HANDBOOK (PH)

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5. REPRESENTING THE PH PROCESS ONTOLOGY IN DAML+OIL

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6. CONTRACT ONTOLOGY

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We view a contract as a specification for one or more processes.

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7. INTEGRATING DAML+OIL ONTOLOGIES INTO RULEML RULES

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RuleML rules are specified “on top of” the DAML+OIL ontology. This same approach also applies to OWL

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The high-level goal of rules “on top of” ontologies has been an important topic of discus- sion in the Semantic Web community, including in architecting standards, since at least 1998. (However, before our work here, this had not been operationalized with a specific technical approach.)

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what? really?

RuleML rules can reference DAML+OIL ontologies.

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the names of predicates appearing in the RuleML rules may be URI’s that reference (i.e., denote) classes and properties in a DAML+OIL ontology.

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the names of individuals appearing in RuleML rules may be URI’s for indi- viduals in DAML+OIL.

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the referenced DAML+OIL ontological knowledge base is viewed as a background theory for the rulebase

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A DAML+OIL property is treated in RuleML as a binary predicate.

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A DAML+OIL class is treated in RuleML as a unary predicate.

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Assertions about instances in a class are treated as rule atoms

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how to define formally the semantics of such integration, i.e., of the hybrid KR formed by combining LP rules on top of DL ontologies

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Description Logic Programs is a KR that captures a large subset of the expressive intersec- tion of Logic Programs and Description Logic.

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Description Logic Programs are (contained in) the expressive intersection of Description Logic and Horn Logic Programs. DLP is thus a subset of FOL.

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What makes it challenging to define the semantics of hybridizing the LP and DL KR’s is the potential for incompleteness or inconsistency.

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expressively re- stricting the ontologies (or the rules) – to be in the Description Logic Programs (DLP) KR

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DLP can be viewed as an “ontology sublan- guage” within the full LP KR.

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The approach in [19]​ is, however, quite limiting for practical purposes since it does not permit predicates defined in the DL ontology to appear in the heads of the LP rules.

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8. RULEML CONTRACTS WITH EXCEPTIONS USING THE PROCESS AND CONTRACT ONTOLOGIES

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9. CONCLUSIONS: SUMMARY OF NOVEL CONTRIBUTIONS

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10. CURRENT AND FUTURE WORK

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