Using Multi-Agent Systems to Simulate Dynamic Infrastructures Populated with Large Numbers of Web Service Enabled Device

Abstract: In this paper, the author use  a  multi-agent  system  to simulate   dynamic  infrastructure  populated  with large number of web-service enabled devices.

Concepts:

Motivation:

    1.Web services are suitable and capable of running natively on embedded devices, providing an interoperability layer and easy coupling with other components in highly heterogeneous shop-floors. (Technologies: DPWS, OPCUA; Projects: SODA,SOCRADES)

    2.According the dynamic infrastructure ,the author give some basic requirements(solutions):

  • Dynamic Discovery of Devices and Services--------(solution:DPWS-enabled devices support WS-Discovery, any device using DPWS can be discovered and it gives more   capabilities in simulating event-based infrastructure: which  are the most likely paradigm to dominate real world environment)
  • Roaming-------------(solution: use mobility capabilities of the agent system to simulate)
  • Volatile devices------(solution: The agent can change the status of simulated service based on their internal strategy)
  • Cooperation capabilities------(solution:variety of available tools such ACL and defined semantics and ontologies can promote cooperation)
  • Heterogeneity------(solution:use agent to wrap heterogeneous functionality to enhance interoperability)
  • Large scale--------(solution:MAS are designed to be scalable and accommodate lots of agents that carry out their task. )
  • Complex Devices Simulation-----(solution:Agents can be grouped to depicts complex behavior)
  • Real and virtual data sources-----(solution: wrap devcie as a web service with DPWS, where others can subscribe to .)
  • Transparent device simulation-----(solution: Agent can discover and use the data emitted by a real device and then create duplicate simulated devices that depict simulated devices that depict exactly the same behavior to the outside of the world.) 
  • Self-* behavior-------------(solution:use the Autonomy characteristic of Agent)

    And the author shows that how DPWS and MAS can address the majority of requirements mentioned(see above solutions) .

    WHY MAS?

  • They support  group  behaviour  of  agents  in  dynamic  situations,and  are  capable  of  simulating  systems  with  large  number of heterogeneous entities behaving differently. As such MAS are  suitable  for  evaluating  distributed  systems  that  involve complex interaction between entities
  • And as agents are autonomous and operate without human intervention ,MAS can model really complex non-deterministic systems governed by common and possiblyeven conflicting goals.

   WHY DPWS?

  • it  runs  on  resource-constrained devices
  • allows dynamic discovery of devices and servicesrunning on devices
  • developer implementations of it are available as open source in Java and C. 

Proposed Method:

     The author use MAS i.e. the JADE platform and DPWS to address the simulation requirements.

     The simulation Environment is :

     

  • Device layer: consists of devices that directly implement web services e.g. via the DPWS protocol, and/or via DPWS gateway. 
  • Execution layer: the MAS hosts several agents that not only  cooperate  but  also  control  the  created  virtual  devices. Each agent represents one SOA-ready devices.
  • Logic layer: describes the scenarios the users run within the simulator.
  • Enterprise layer:various  services  and  applications  can  communicate  via  web services with the devices, both real and simulated ones.

And The simulation environment consists of a basic set of agents:

  • Management Agent: evaluation of user arguments, creation of other agents and other management functions, e.g. logging etc.
  • Device Explorer Agent : discover all the DPWS-enabled devices with a specific scope.
  • Device Generator Agent: receive and execute requests towards creating and initializing service agents.
  • Scenario Agent: is specific  for each scenario as it executes its strategy.
  • Service Agent:simulate a DPWS service and are visible to the external world via DPWS communication.
posted @ 2011-03-04 13:39  leon.wei  阅读(436)  评论(0)    收藏  举报