Angelo Furno and Eugenio Zimeos presentation at the 2nd Awareness Workshop on challenges for achieving self-awareness in autonomic systems at SASO 2012, Lyon.

1. ENHANCING WEB PROCESS SELF-AWARENESS
WITH
CONTEXT-AWARE SERVICE COMPOSITION
Angelo Furno
Ph. D. Candidate
University of Sannio
Eugenio Zimeo
Ph. D. Tutor
Ph.D. Forum - AWARENESS, SASO 2012 - Lyon University of Sannio
2nd Workshop on Challenges for Achieving
Self-Awareness in Autonomic Systems
University of Sannio, Department of Engineering
82100 Benevento - Italy

2. Context-aware Semantic Service Design & Composition
Context: “any information that can be used to characterize the situation of an entity. An entity
is a person, place, or object that is considered relevant to the interaction between a user and
an application, including the user and applications themselves.” (Dey and Abowd, 1999)
 Problem: to take context into account during semantic service design and automatic
composition
• context awareness to enhance Web Process self-awareness
− essential for implementing self-managing properties of the autonomic computing vision
 Pervasive scenario example: TV-Show Episode retrieval and reproduction
Context-aware
Service Domain
Problem specification
and current context
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

3. Autonomic Workflow
AW life-cycle
 Autonomic Workflow (AW)
• executable composition of automatic/manual services
• able to automatically proceed towards the goal
− even if external events change the execution context
• AW life-cycle:
− direct action flow (plan-bind-execute)
− reaction flow (self-awareness)
 Context-aware Service Composition
 Initial definition of the autonomic workflow (plan)
• Re-planning (parts of) already defined workflow (plan1)
 SAWE: Semantic Autonomic Workflow Engine
• Developed at University of Sannio
• Implements the autonomic workflow lifecycle
• OWL + OWL-S
• for Semantic Web Service design
• and problem semantic description SAWE
• What about context support?
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

4. Context Model
 Application state
• set of variables and corresponding values the application is able to access or modify.
• Internal state
− set of variables only visible to
the application
 input, output
 referred by pre/post conditions
• External state
− set of variables accessible by:
 users
 devices
 other applications
− the context
 Context-aware Web Services
• WS exhibiting dependencies from the context in pre/post-conditions
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

5. OWL-Ctx: (top-level) ontology for context
 Extensible OWL ontology for describing contexts
• semantically model contexts
• context-dependent conditions
 Top-level ontology
• context as a set of context dimensions and values
 Partial context middle-level ontology:
• domain-independent context dimensions (time, location, etc.)
 Designers may specify domain-specific context dimensions and their relationships
OWL-Ctx
middle-level
OWL-Ctx
top-level Media-Ctx
specification
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

6. OWL-SC (1): Top-level ontology
 Extension of the OWL-S service ontology
• for describing context-aware semantic services
 Designers may describe slightly different versions of the same service
• by defining context adaptation rules over a basic OWL-S description
− context condition + context adaptation
OWL-S
− profile, process or grounding properties are adapted when conditions are satisfied
 OWL-S Profile, Process and Grounding middle-level ontology
• Contexts or Context dimension values may be used in CTX-Conditions
− a current context reference is used to refer the current situation
 may be automatically updated by a monitoring component
OWL-SC
(top level ontology)
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

7. OWL-SC (2): Context Conditions and Adaptations
 Context adaptations:
• Defaulting an input/output parameter
• Nulling a parameter, not applicable for a specific context condition
• Changing the owls <process:parameterType> of an input/output parameter to a different ontology concept
• Replacing pre-conditions or effects of the basic OWL-S service description
• Changing the WsdlAtomicProcessGrounding input/output section of an atomic Process with a new Wsdl
MessageMap
• Changing the WsdlAtomicProcessGrounding section of an atomic Process with a new WSDL operation and/or
WSDL portType
SWRL context condition (diskSpace: Pervasive scenario)
 Context-dependent conditions:
• Expressed using Semantic Web Rule
Language (SWRL)
• Currently supported by our OWL-SC ontology:
− current_ctx matches ref_ctx
− current_ctx includes "concept hasValue ontology_individual"
− current_ctx includes "concept.datatype_property = value"
− current_ctx includes "concept.object_property hasValue individual"
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

8. Context-aware Composition Tool for Autonomic Workflows
 Five-Step Composition Process
• manually triggered for initial workflow definition, automatically triggered on monitored events requiring re-planning
1. OWL-SC problem and domain conversion into internal representation
2. Domain and Problem Contextualization (+ serialization)
3. Planning
4. Deserialization and Plan Validation
− Rules & Constraints
5. Contextualized Translation into Standard Language Executable Business Process (WS-BPEL, XPDL, etc.)
1 2 3 4 5
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

9. Pervasive Scenario: a Context-aware WS-BPEL Composition
disk space swrl ctx cond.
Context-aware
Service Domain
Problem specification
and current context
OWL-S conversion + Contextualization +
PDDL planning + WS-BPEL serialization
WS-BPEL
contextualized
business process
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

10. Future Work
 Problems:
• Context may change during planning
• Contextualization not always possible before/after planning
− e.g.: for an abstract service, more than one post-condition may fit the context
− only one of them satisfies the pre-conditions of the next services
 e.g. there is disk space for retrieving a HD file but the player is not able to play it
− it is possible that valid composite solutions are indirectly excluded during domain construction
 e.g. the HD file retrieval service is selected, but it won’t be possible to reproduce it
 Solution:
• Contextualization should be performed during planning
 Development of a new planner
• supporting context evaluation at each step of the planning process
• business constraints verification during planning
• support for more complex context conditions and control flow structures
− choice, loops, etc.
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

11. References
1. L. Bevilacqua, A. Furno, V. di Carlo, and E. Zimeo, “A tool for automatic generation of ws-bpel
compositions from owl-s described services,” in Software, Knowledge Information, Industrial
Management and Applications (SKIMA), 2011 5th International Conference on, sept. 2011, pp. 1 –8
2. L. Bevilacqua, A. Furno, V. di Carlo, and E. Zimeo, “Automatic generation of concrete compositions
in adaptive contexts [to appear],” in Mediterranean Journal of Computers and Networks, oct.
2012
3. A. Furno and E. Zimeo, “Context-Aware Design of Semantic Web Services to Improve the Precision
of Compositions [to appear],” in International Conference on Context-Aware Systems and
Applications (ICCASA), nov. 2012
4. G. Tretola and E. Zimeo, “Autonomic internet-scale workflows,” in Proceedings of the 3rd
International Workshop on Monitoring, Adaptation and Beyond, ser. MONA ’10. New York, NY,
USA: ACM, 2010, pp. 48–56. [Online]. Available: http://doi.acm.org/10.1145/1929566.1929573
5. M. Polese, G. Tretola, and E. Zimeo, “Self-adaptive manage-ment of web processes,” in Web
Systems Evolution (WSE), 2010 12th IEEE International Symposium on, sept. 2010, pp. 33 –42
Thank You
For Your Attention!
Angelo Furno - University of Sannio, Benevento - Italy
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AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems