Planning and Scheduling for
Dynamic Workflow Management
Dr Nikolay Mehandjiev
Department of Computation, UMIST, Manchester, U.K.
E-mail: mehandjiev@acm.org WWW: www.co.umist.ac.uk/~ndm
Aim: Promoting the effective application of AI P&S techniques to WM
Roadmap:
• similarities between P&S and WM
• areas where P&S can provide substantial input to dynamic WM
Some related projects
Motivation
Workflow Management
– Growing need for
• Business Process Modelling
• Supply Chain Execution
– Rapidly changing processes
– Static tools incapable of dynamic optimisation
AI Planning and Scheduling
– Applied to a range of real work problems
– Mostly linked with materials and production
– Potential for Workflow Management
A simple workflow process
1. Customer selects laptop
2. Customer sends specs to purchasing
3. Purchasing requests quote from supplier
4. Supplier sends quote to purchasing
5. Purchasing confirm quote with customer
6. Purchasing send purchase order
7. Supplier sends laptop to customer
8. Supplier sends invoice to purchasing
9. Purchasing send cheque to supplier
Workflow Management
Semi-automatic composition
Effective monitoring and prediction
Optimisation
Re-planning
Conflict identification and
resolution
Role for Planning and Scheduling
Mapping similarities
Highlighting differences
Terminology
Design-time work
WM: humans assisted by simple tools
P&S: mainly automatic by software
Representations
WM: domain-oriented and user-friendly but vague
P&S: mathematically formal and semantically precise
Languages
WM: scripting languages for coordination of activities
P&S: AI plan languages are higher level
Requirements
Short-term
Integration of scheduling and resource allocation in WM tools
Re-planning
Generating workflow definitions from process models
Process mining
Medium-term
WM support for skilled work
User empowerment
Visualising work
Long-term
Flexibility
Evolvability and Adaptiveness
Decentralised management
Roadmap themes
Human factors
State-of-art
WM: tailorable workflow systems
P&S: mixed-initiative planning
Research issues
User empowerment versus centralised control
Balance human and software effort at different stages
Visualising the way planners work
Recommended actions
Trans-disciplinary workshops
Prototype supporting user control
Infrastructure
State-of-art
WM: WfMC reference architecture
P&S: PDDL and ADL
Research goals
From objects through components to agents
Developing planning and scheduling servers
Recommended actions
Draw up a reference architecture
Interface standards
Domain and business modelling
State-of-art
Process management: ARIS, iThink, IDEF, PIF, PSL, WPDL
Knowledge engineering: CommonKADS, CoRE
Ontologies: CYC, Enterprise, TOVE, DAML-OIL/OWL
AI planning: ADL, PDDL, STRIPS/PDDL, GIPO
Research goals
How to synthesise BPM, P&S and ontology modelling languages into a
language which is:
•Useable by domain experts;
•Has rigorous semantics and mathematicall formal;
•Executable
•Translateable into other formalisms
•Suitable for planning
Recommended actions
Taxonomy of languages and tools
Organise a hands-on workshop on modelling
Planning and scheduling
State-of-art
Many planning techniques available, current trends to:
• integrated planning and scheduling
• mixed initiative planning
• constraint-based approaches
Some tools to support these, eg ILOG Scheduler, but expert-oriented
Successful industrial applications but not in WM
Research goals
How to best combine human capabilities with P&S?
Create interfaces so that planners are easily used by domain experts.
Recommended actions
Definition of graduated reference problems
Enactment / execution
State-of-art
Conditional planning
Reactive planning
Research goals
flexible working with overall plan
use of plan repair or re-planning techniques for exception handling
combination of plans for multiple actors
Requirements
Techniques for monitoring execution
Techniques for exception handling
Adaptation, optimisation & metrics
State-of-art
Mature optimisation techniques coming from AI and OR
Using multiple criteria for planning and scheduling
Research goals
Appropriate metrics for WM – time and cost only?
Languages for providing metrics to the system
Combination of metrics
Requirements
User-definable metrics and optimisation parameters
Integration with process design and enhancement tools
Interaction with the user
Main recommendations
• To raise awareness of real challenges and constraints in
workflow domain;
• To make application and tool developers aware of what AI
planning and scheduling research has to offer;
• To address practical issues of integrating planning and
scheduling technology into suites of application software,
and of making the techniques usable by typical software
engineers, analysts, etc.
• To form a consensus on medium and long term research
goals.
• The RoadMap should be seen as a living document and be
extended and updated regularly.
Related work at UMIST
1. Tailorable workflow systems and EUD - ECHOES
2. Allocating tasks in distributed teams – SAMBA, BT Exact
3. Semi-automatic allocation of tasks to agents - RAMASD
4. Agent-based workflow support systems – Agentcities & IntLog
5. Supporting the automatic formation of Virtual Enterprises
ECHOES
workflow description
organisational taxonomy
Application
Achievements
• Users can change workflow during execution under an “intelligent guardian”
• Highly responsive mode of interaction
• Multi-aspect visual language that can evolve
• Architecture to support all this
SAMBA
visualisation and
monitoring agent
control
viewpoint 1
control
viewpoint 2
business process layer
agent workflow
support software layer
(a)
(b)
BT Short Term Fellowship (1998)
Aim: Provide work coordination software that:
• Allows workers to control their work
• Allows managers to modify local business rules
• Informates people about the work process
• Supports team building and social interaction processes
control
viewpoint n
RAMASD
Funded by BT Exact as a PhD studentship (June 1999 – June 2002)
Allocate behaviour to agents using
• Roles
• Role models
• Role algebra
Method
• Use synthesis-based design process
• Allocated by constraint satisfaction algorithm
• Incorporated in the agent-building toolkit Zeuss
Application
•Currently for the design of agent systems
•Can be used to allocate tasks to performers
Agentcities.ORG network snapshot taken from http://www.agentcities.org/Network/
IntLog
Co-optimise production and logistics services.
Agents allocate work using extensions to Contract Net protocol.
An Agentcities prototype related to EC-funded project MaBE (www.mabe-project.com)
Summary
Workflow Management TCU produced a Roadmap on the use of AI P&S
techniques to Workflow Management.
This presentation summarised findings of the Roadmap regarding:
• Similarities and differences between the two areas;
• Open research issues and actions in the area of P&S application to
Workflow Management.
• Requirements for applying P&S techniques to Workflow Management.
Several projects were then described briefly as an example of activities
relevant to the Roadmap.
For further information regarding this presentation, please e-mail me on
mehandjiev@acm.org