Context Management in Event Marketplaces

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Context Management in Event Marketplaces

  1. 1. Information Management Unit / ICCS of NTUA www.imu.iccs.gr 7th International Workshop on Semantic Business Process Management Context Management in Event Marketplaces Yiannis Verginadis Ioannis Patiniotakis Nikos Papageorgiou Dimitris Apostolou Gregoris Mentzas Nenad Stojanovic FZI ForschungszentrumInformation Management Unit Informatik, Karlsruhe,Institute of Communication and GermanyComputer SystemsNational Technical University of Athens
  2. 2. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Overview of presentation  Introduction  Situation-Action-Networks (SANs)  Event-based Context Management  Illustrative Scenario  Conclusions
  3. 3. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Introduction Context is “any information that can be used to characterize the situation of an entity, i.e., a person, place, or object that is considered relevant to the interaction between a user and an application, including the user and applications themselves.” [1]. Events from event marketplaces are an important source of context for service-based applications and systems that consume them because they may convey important information, which is relevant for service execution and adaptation.[1] Dey, AK & Abowd, GD: Towards a Better Understanding of Context and Context-Awareness, In Proceedings ofthe PrCHI 2000 Workshop on the What, Who, Where, When, and How of Context-Awareness, pp. 304-307 (2000)
  4. 4. Information Management Unit / ICCS of NTUA www.imu.iccs.grThe Event Marketplace (1/2) Event-driven World: services exchange events asynchronously Events are input for services Just as Services should be tradable, so should events To receive events, the sources of events must be known A marketplace like a search engine provides visibility to distributed sources of events Nowadays, Everything can generate Events
  5. 5. Information Management Unit / ICCS of NTUA www.imu.iccs.grThe Event Marketplace (2/2) A platform offering a service based architecture, for maintaining subscriptions (along with their cost), receiving and relaying event notifications with the aim of different and distributed event sources integration (e.g. Pachube).
  6. 6. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Overview of presentation  Introduction  Situation-Action-Networks (SANs)  Event-based Context Management  Illustrative Scenario  Conclusions
  7. 7. Information Management Unit / ICCS of NTUA www.imu.iccs.grMotivation Not everything can be captured at design time  but we can predefine the Goals to be pursued and achieved Unexpected or non-ordinary situations must be identified  from streams of events exchanged in SBA environment and structure  they are usually not considered at design-time Selection of (re)Actions to the unexpected situations at runtime  exploiting the current application context information originating from… Identified situations; they update and enrich application context In previous work, we have proposed Situation Action Networks (SANs) framework
  8. 8. Information Management Unit / ICCS of NTUA www.imu.iccs.grA Basic SAN The black arrow indicates the order of visiting child nodes. Parent is visited fist. Goal expresses what is pursued. I.e. the purpose of process / app Situation “monitors” when a situation occurs. Blocks meanwhile Context - Condition  Updates and enriches app context from situation metadata  Checks whether context conditions hold Action to take if situation occurs and context condition is true  Situation-driven execution, i.e. execution when necessary
  9. 9. Information Management Unit / ICCS of NTUA www.imu.iccs.grMore complex SANs Root Goal Root Context Situation Condition 1 Sub-Goal Context Situation Action Condition 2 Root Goal S0 CC 0 // Sub-Goal 1 Sub-Goal 2 S1 CC1 A1 S2 CC2 A2
  10. 10. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Overview of presentation  Introduction  Situation-Action-Networks (SANs)  Event-based Context Management  Illustrative Scenario  Conclusions
  11. 11. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Event-based Context Management  We discuss a Context Model that associates Context elements with Events and SANs  We provide two approaches for acquiring context from simple or complex events and instantiating our context model. Both approaches use the SAN Editor for:  defining SPARQL queries to specific RDF event payload information that can update the values of an entity’s context elements  defining SANs that can use information from several event streams, analyse them and/or combine them with external services, in order to update the derived values of context elements. In this way, we succeed in acquiring higher level context compared to the lower level information that events carry.
  12. 12. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Context Model (1/2)  We extend and use a context model for facilitating event-based context detection and derivation functionality,  in order to better understand situations in dynamic service oriented environments that demand for new additional information sources or/and lead to a number of service adaptations as means for successfully coping with dynamic environmental changes.  This model is based on the W4H model [9] that describes the five main elements associated within a context; the five elements are arranged into a quintuple (When, What, Where, Who, How).[9] Truong, HL, Manzoor, A & Dustdar, S: On modeling, collecting and utilizing context information for disaster responses inpervasive environments, In Proceedings of the 1st int. workshop on Context-aware software technology and applications, pp.25–28 (2009)
  13. 13. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Context Model (2/2) This Context Model expresses the temporal (i.e. When), spatial (i.e. Where), declarative (i.e. Who, What) and explanatory (i.e. How) dimensions of context having as central point of focus the notion of Entity and the association of Context elements and Events
  14. 14. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Context Model Lifecycle
  15. 15. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Overview of presentation  Introduction  Situation-Action-Networks (SANs)  Event-based Context Management  Illustrative Scenario  Conclusions
  16. 16. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Marine Scenario – AIS Hub (1/2)  The International Maritime Organization (IMO) requires all vessels to carry an AIS (Automatic Identification System) transponder on board,  which transmits their position, speed and course, among some other static information, such as vessel’s name, dimensions and voyage details.  A vast amount of real time events are available from portals (http://www.aishub.net/ ) connected to automatic identification systems (AIS) that contain important vessel information worldwide.
  17. 17. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Marine Scenario – AIS Hub (1/2)
  18. 18. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Context Model Specialization (1/2)  In the AISHub Scenario we consider the “Vessel” as the entity of interest.  In order to capture contextual information related to Vessels’ context, we have defined the following Context Elements:  Speed, Course, Position, Status, Distance2Port  Context Model Specialisation using SAN Editor
  19. 19. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Context Model Specialization (2/2)
  20. 20. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Detecting Context  Using SAN Editor, we are able to define SPARQL queries to specific event payload information that update the values of an entity’s context elements.
  21. 21. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Context Model Instantiation for Position Context Element
  22. 22. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Deriving Context using SANs (1/2)  We define a number of SANs that can use information from several event streams and combine them with external services in order to update the derived value class of context elements.
  23. 23. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Deriving Context using SANs (1/2)  Context derivation can be more complex and may involve multi-level SANs. Upon traversal of the following SAN the derived value class of the Status context element will be updated
  24. 24. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Deriving Context using SANs (2/2)
  25. 25. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Overview of presentation  Introduction  Situation-Action-Networks (SANs)  Event-based Context Management  Illustrative Scenario  Conclusions
  26. 26. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Ongoing Work  The Detection and Derivation of Context from Events is considered essential for Event Marketplaces  The proposed context management approach aims to cover the increased needs of such dynamic environments and consists the pillar of our ongoing work regarding:  Situation Awareness  Dynamic Event Subscriptions Recommendations  Service Adaptation Recommendations
  27. 27. Information Management Unit / ICCS of NTUA www.imu.iccs.gr Thank you for your attention!!!

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