Upload
nailah
View
64
Download
0
Embed Size (px)
DESCRIPTION
Hierarchical Task Network (HTN) Planning for Grid/Web Services Composition and Workflow Austin Tate AIAI, University of Edinburgh. Simple Messages. HTN Planning could be a useful paradigm Compose workflows from requirements and component/template libraries - PowerPoint PPT Presentation
Citation preview
1
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
Hierarchical Task Network (HTN)Planning for Grid/Web Services
Composition and Workflow
Austin TateAIAI, University of Edinburgh
2
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
Simple MessagesSimple Messages
HTN Planning could be a useful paradigm– Compose workflows from requirements and component/template libraries– Covers simple through to very complex (pre-planned) components– Allows for execution support, reactive repair, recovery, etc.
Simple extendable underlying “plan” representation from our work on <I-N-C-A>
– Activities– Constraints
Extendable framework from <I-N-C-A> could be useful– Issues– Annotations
Could be complementary component technology in many other projects described at this workshop
3
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
HTN PlanningHTN PlanningActivity CompositionActivity Composition
A1
A2
A3
A5A4
“Initial” Plan
Refine
Introduce activities to achieve preconditionsResolve interactions between conditions and effects
Handle constraints (e.g. world state, resource, spatial, etc.)
“Final” Plan
A2.2A2.1
A1
A3
A5A4
Plan Library
A2 Refinement
S2S1
Augment to describeGrid/web services
Augment to describeGrid/web requirements
4
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
HTN PlanningHTN PlanningInitial Plan Stated as “Goals”Initial Plan Stated as “Goals”
Refine
Plan Library
Ax Refinement
S2S1
P
“Initial” Plan
P & Q
Initial Plan can be any combination of Activities and Constraints
“Refined” Plan
A1.2A1.1
Q
P
5
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
Relevant AIAI Work to DateRelevant AIAI Work to Date O-Plan
– On-line web service exposing API via CGI scripts since 1994– HTTP interface since 1997– Simple - single user single-shot plan generator– More comprehensive - multiple users with multiple roles, long transactions,
collaborative planning, execution and plan repair on failure– Air Campaign Planning Workflow Aid - people and systems
I-X– I-X supports the construction of mixed-initiative agents and systems which are
intelligible to their users and to other systems and agents– Dynamic workflow generation and reactive execution support– I-Q query adaptor for OWL, OWL-S lookups via CMU Matchmaker, Semantic
Web Queries via RDF, DAML, OWL and RDQL (AKTive Portal)– I-Plan planning aid (to be packaged as a web service composition tool)
CoAX and CoSAR-TS– Coalition Command and Control/Search and Rescue Task Support– Use on CoABS Grid and with KAoS Domain and Policy Management
O-Plan Unix SysAdmin AidO-Plan Unix SysAdmin Aid
O-Plan MOUT Task Description,O-Plan MOUT Task Description,Planning and Workflow AidsPlanning and Workflow Aids
8
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
O-Plan as a Workflow PlannerO-Plan as a Workflow Planner
Air Campaign Planning (ACP) Workflow – 1996 Real ACP Process Models utilised Composes workflow Process from a range of
system and user capability descriptions Models the creation and modification of
“Process Products” by effects and conditions on process steps. Values of attributes of each product/object changed during process. E.g. status of documents.
Supports planning, execution monitoring and plan repair on failure.
9
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
I-TechnologyI-Technology
Cooperation and Communication
I-DEDomainEditor
I-P2
ProcessPanels
I-PlanPlanningAid
CoABS Grid,KAoS,
AKTBus,XML Sockets,
Jabber,[Globus GT3]
Other Agents &Services
I-Q Adaptor
10
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
<I-N-C-A> Ontology for <I-N-C-A> Ontology for Synthesised ArtifactsSynthesised Artifacts
Issues
Nodes E.g. activities in a process or parts in a physical artifact
ConstraintsCritical Constraints (shared across multiple components)Auxiliary Constraints (localised to a single component)
Annotations E.g. decision rationale and other notes
Used for Processes and Process Products
11
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
<I-N-C-A><I-N-C-A>
Constraints
Issues
Nodes
Space of Legitimate Bahaviours
Issues or ImpliedConstraints
NodeConstraints
(e.g. include activity)
DetailedConstraints
I
N
C
A=Annotations
12
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
Constraints
Issues
Nodes
Space of Legitimate Behaviours
Issues or ImpliedConstraints
NodeConstraints
DetailedConstraints
I
N
C
A=Annotations
I-X and <I-N-C-A>I-X and <I-N-C-A>
Do (IH)
Choose (IH)
IH=Issue Handler (Agent Functional Capability)
PropagateConstraints
13
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
I-X Aim is a Workflow and I-X Aim is a Workflow and Messaging “Catch All”Messaging “Catch All”
Can take ANY requirement to:– Handle an issue– Perform an activity– Respect a constraint– Note an annotation
Deals with these via:– Manual activity– Internal capabilities– External capabilities– Reroute or delegate to other panels or agents– Plan and execute a composite of these capabilities
Receives reports and interprets them to:– Understand current status of issues, activities and constraints– Understand current world state, especially status of process products– Help user control the situation
Copes with partial knowledge
CoSAR-TS Demo CoSAR-TS Demo ArchitectureArchitecture
I-Plan(Planning Service)
I-CE and I-K-CEI-CE and I-K-CEI-X/KAoS Composer & EnactorI-X/KAoS Composer & Enactor
I-CEI-CE
Enactment (e.g. via I-P2)Enactment (e.g. via I-P2)
EnforcementEnforcement (e.g. via KAoS)(e.g. via KAoS)
18
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
http://i-x.info
http://www.aiai.ed.ac.uk/project/ix . . . coax . . . cosar-ts . . . coakting
http://www.swsi.org
Thanks to my co-workers on the I-X and CoSAR-TS projects:– Jeff Dalton, Stephen Potter, Stuart Aitken, Jessica Chen-Burger,
John Levine, Natasha Lino, Clauirton Siebra– IHMC: Jeff Bradshaw, Andrzej Uszok
Further InformationFurther Information
19
Artificial Intelligence Applications InstituteCentre for Intelligent Systems and their Applications
Shared Task Model – Mixed initiative model of “mutually constraining the space of products”.
Shared Space of Options – for the product.Shared Model of Agent Capabilities -
handlers for issues, functional capabilities and constraint managers.
Shared Understanding of Authority – management of the authority to handle issues and act which may take into account options.
Shared Product Model – using constraints on the space of products (<I-N-CA>).
Shared Task and Activity ModelShared Task and Activity Model
UserRole 1
O-PlanWebPlanner
Other Agents
UserRole 2
*
Nodes
:
Constraints
~
Preferences
|
Options (Alternative Activities)
Evaluations
+ - =
#
Evaluation Criteria
Activity
Record RationaleMake Choice
“Annotation,Statements,Arguments,Reports
?
Issues
Version N
Document/
Product
of Collaboration
Properties
N
I
C
AOptions for the Activity to be performed may beevaluated against evaluation criteria. The result ofevaluations may be a Pro (+), Con (-), or neutral (=).
Document/
Product
of Collaboration
Version N+1
Properties
Product Model Refinement StepProduct Model Refinement StepUsing <I-N-C-A> FrameworkUsing <I-N-C-A> Framework