EnhancingWeb Process Self-Awareness with Context-Aware Service Composition

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

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EnhancingWeb Process Self-Awareness with Context-Aware Service Composition

  1. 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. 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 2 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  3. 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 3 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  4. 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 4 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  5. 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 5 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  6. 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 6 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  7. 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 7 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  8. 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 8 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  9. 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 9 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  10. 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 10 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems
  11. 11. References1. 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 –82. 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. 20123. 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. 20124. 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/10.1145/1929566.19295735. 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 11 AWARENESS, SASO 2012 - 2nd Workshop on Challenges for Achieving Self-Awareness in Autonomic Systems

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