OWL-P: Protocols for Processes Toward the Pragmatic Web Munindar P. - - PowerPoint PPT Presentation

OWL-P: Protocols for Processes

Toward the Pragmatic Web

Munindar P. Singh (Students: Amit K. Chopra, Ashok U. Mallya)

singh@ncsu.edu

Department of Computer Science North Carolina State University http://www.csc.ncsu.edu/faculty/mpsingh/

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Why Processes and Protocols?

Heavy interest from IT practitioners. Standardization efforts. Match with Semantic Web research. Tractable problems with high impact. Great application area for semantics. Segue into upcoming research program.

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Emphases of this Project: 1

Commitment Protocols Rule-Based Commitment Protocols Protocols I m p l e m e n t a t i

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a n d e n a c t m e n t M

• d

e l i n g a n d v a l i d a t i

• n

M

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i t

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i n g a n d c

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p l i a n c e Dynamic Organizations

Not in 2004 Not in 2004

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Emphases of this Project: 2

Protocols: Support reuse via abstraction and composition for process modeling and enactment. Commitments: Enable flexible modeling and enactment of protocols. Engineering: Full automation is not needed. Tools needed for engineering. Modeling and validation. Implementation and enactment. Monitoring and compliance.

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Trends and Assessment

Increasing # of business protocols. IOTP , Escrow, SET, NetBill, . . . RosettaNet: 107 Partner Interface Processes (PIPs). ebXML Business Process Specification Schema (BPSS). Generally highly limited: two party, request-response protocols. No commitments; no formal semantics. Limited support for modeling or enactment.

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Simple Scenario and Example Run

A customer (C) looks up a book at a vendor (B) and is quoted price and availability. C orders the book from B. B ships to C. C pays B.

reqQuote(c,b,g) sendQuote(b,c,g,p) sendAccept(c,b,p) sendMoney(c,b,p)

s0 s1 s2 s3 s4 s5

Bookstore, b Customer, c sendGoods(b,c,g)

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Challenges: Modeling

Refinement: pay by credit card versus pay. Extensibility: verify C’s attributes, e.g., age. Adjustment: receive payment before shipping; receive book before paying. Alternative execution examples: B arranges for a shipper (S) to deliver the book to C. C pays via bank (K). Compose a process from the above.

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Process View: Global or Protocol?

Customer

Select Send Receipt Ship Pay

Bookstore Shipper Bank Customer Bookstore Customer Bookstore Customer Bookstore Bookstore Customer Bank Shipper

Ship Pay Pay Select Order Ship

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Example Run: Pay via Bank

reqQuote(c,b,g) sendQuote(b,c,g,p) sendAccept(c,b,p) sendGoods(b,c,g) authPay(c,b,p) s0 s1 s2 s3 s4 s21 Bookstore, b Customer, c s5 Customer's Bank, k sendMoney(k,b,p)

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Example Run: Shipper Protocol

s10

reqQuote(m,s,[gv]) sendQuote(s,m,[gv],q) sendAccept(m,s,[gv],q)

s11 s12 s13 s13

sendGoods(m,g,s)

s14

Shipper, s Sender, m

s15

sendMoney(m,s,q)

s16

sendGoods(s,v,g) Receiver, v

s15

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Example Run: Composed Purchase

reqQuote(c,b,g) sendQuote(b,c,g,p) sendAccept(c,b,g,p)

s0 s1 s2

s3

s4 s5

authPay(x,p)

s21

sendMoney(k,x,p) reqQuote(b,x,[gc]) sendQuote(x,b,[gc], px) sendAccept(b,x,[gc],px)

s11 s12 s13 s13

sendGoods(b,g,x)

s14

sendMoney(b,x,px)

s16

sendGoods(x,c,g)

Shipper, x Bookstore, b Customer, c Bank, k Shipping Payment

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Challenges: Enactment

Behaving adaptively: decide dynamically to ship before payment to trusted Cs. Handling exceptions. External problems: cannot ship book. Detecting violations: no payment; book arrives damaged. Correcting violations: remind, complain, refund, . . . Exploiting opportunities: combine orders from same C.

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Example Run: Return and Refund

Example: Uniform Commercial Code (UCC) allows returns with refunds for goods that are received damaged.

reqQuote(c,b,g) sendQuote(b,c,g,p) acceptQuote(c,b,p) sendMoney(c,b,p)

s0 s2 s3 s4 s5

Bookstore, b Customer, c

s5 s18

returnGoods(c,b,g) sendGoods(b,c,g) sendRefund(b,c,p)

s19 s1

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Architecture

Knowledge Base Rule Base lnternal Policy Protocol Rules Main updates queries

Maintains protocol state: Commitments and propositions, roles being played, ... Ex: Business policies, pricing policies Rules dictated by protocols being enacted

consults

Local domain Public domain Protocol Specified in OWL-P Commitments Roles Messages Propositions Rules Messages Binds to roles, interacts with other roles. Agent Playing a Role Usually several protocols, each with multiple roles Usually several roles per agent

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Deliverables

OWL-P: OWL for protocols. Roles. Messages: content as propositions and commitments. Rules to describe messages and role constraints. Autonomous communicating agents (JADE). Tool to generate skeletons from OWL-P . Rule-based policies that help agents satisfy their protocol roles. Methodology to develop agents.

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Functionality and IP Status

Open source; on SemWebCentral 6/30 onwards. Preliminary versions implemented for OWL-P . Multiagent architecture to enact. Policy-based architecture for each agent. Upcoming versions. Incorporate rules better (6/30). Compose protocols (6/30). Fully treat commitments (9/30). Represent quality of service for configuration (9/30) and apply it (12/31). Incorporate policies (12/31).

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Papers on this Topic

“Protocols for Processes: Programming in the Large for Open Systems.” OOPSLA, Oct 2004. “Agent Communication Languages: Rethinking the Principles.” IEEE Computer, 31(12):40–47, Dec 1998. “An Ontology for Commitments in Multiagent Systems.” AI & Law, 7:97–113, 1999. “Reasoning About Commitments in the Event Calculus: An Approach for Specifying and Executing Protocols.” Annals Math & AI, 42(1-3), 2004. “Verifying Compliance with Commitment Protocols.” J. Auton Agents & MAS, 2(3):217–236, Sep 1999.

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