Modeling and Assessment ofProduction Printing Workflows Using

Petri NetsRajuRaju GottumukkalaGottumukkala

Computer Science DepartmentComputer Science DepartmentLouisiana Tech UniversityLouisiana Tech University

Dr. Tong SunDr. Tong SunPrincipal ScientistPrincipal Scientist

Adaptive & Smart Document System LabAdaptive & Smart Document System LabXerox Innovation GroupXerox Innovation Group

September 7, 2005September 7, 2005BPM Conference PresentationBPM Conference Presentation

Nancy, FranceNancy, France

©2004 Xerox Corporation. Xerox®, The Document Company® and the digital X® are trademarks of Xerox Corporation. All rights reserved.

Challenges & Motivations

– Major paradigm shift in the printing industry:• From a traditional human-intensive manufacturing process into more

automated digital workflows• Product centric => Solution centric

– In automated digital workflows,• Ever increasing number of heterogeneous devices and software

applications seamlessly interoperate with each other• High-speed, large volume, highly concurrent execution

– Business value:• Improve customer current production process efficiency by migrating into

digital workflows• Help customer make better-informed business decision• Foresee the performance implications to meet changing business needs

(what-if analysis)

Why Using Petri Nets?

– Single FORMAL model for the process analysis,verification, and simulation

– Open source tools available (Renew, Design/CPN, etc.)

– Promising new development fronts• PNML

• Petri Net Ontology

• BPEL2PN

Production Printing Workflows: Core Domain Model

– Service Model• Built upon the SOA and Semantic Web Service notions

• Production Printing Service Specifics:

– Large grain logical model (functionality externally visible)

– Building block of a production printing workflow

– Document Model• Describes the entire lifecycle of the content data model

• Transfer modes: spool, stream.

– Job Model• Intent-based (what) vs. instruction-based (how)

• Print job dynamic operational behavior and lifecycle

Production Printing Workflows in Petri Nets(1)

– Executable Service Net (ESN)

Production Printing Workflows in Petri Nets(2)

– Executable Workflow Net (EWN)• A superset of ESNs = ESNs + Control Elements• Input to Renew tool to simulate process model

– a user given set of simulation input profiles: workload, jobarrival rate, document types, etc.

– service capability specification» Setup time» Processing time» Failure probability» Repair Time

– generate the process performance metrics:» Turnaround time & throughput» Waiting time» Service utilization rate

Production Printing Workflows in Petri Nets(3)

– Abstract Service Net (ASN)• A finite set of service states (as Places) and service

transitions (as Transitions)• Job is a Token• Document is characterized as Token properties

– Abstract Workflow Net (AWN)• A super net of ASNs = ASNs + Control Elements• Input to Design/CPN Tool for workflow model verification

(deadlock, liveness, reachability, etc.)

Simulation-driven Workflow Assessment Tool

3rdParty WorkflowModelingTool (s)

Petri Net Simulator(Renew)

Data Analysis Component

Simulation Components

GUI EditorSimulation resultreporter

EWN Generator

ESN Templates

Event Driven Simulation Engine

Workflow Simulation Interface

Workflow Model

Constructor

Database

Trace Generator

Scenario – Sample Process Models

Scenario – Sample Models (2)

Abstract Workflow Net

Executable Workflow Net

On-going & Future Work

– Seamless mapping/integration between standard XML-basedworkflow specifications (e.g. BPMN, BPEL, JDF) into Petri Net(or PNML)

– Extension scheme for Service Net (generic vs. specific)

– Extend the construction scheme of Abstract/ExecutableService Net based on Job lifecycle and Document lifecycle

– Extend the construction scheme of Abstract/ExecutableWorkflow Net based on Document’s semantic behavior

– Semantic Web, Web Service, OWL-S