1. Blue Bear Systems Research Hardware Architectures for Distributed Agents Dr Simon Willcox 24 th Soar Workshop 9 th – 11 th June 2004 Building 32, Twinwoods Business Park, Clapham, Bedfordshire MK41 6AE Tel: 01234 212001 Email: simon@bluebearsystems.com www.bluebearsystems.com www.bluebearsystems.com

2. Blue Bear Systems Research Presentation Overview Objectives Objectives Clustering Approaches for Multi-Agent Systems Clustering Approaches for Multi-Agent Systems Agent Hardware Agent Hardware Agent Communication Framework Agent Communication Framework Prototype Soar Implementation Prototype Soar Implementation Example Problem Example Problem

3. Blue Bear Systems Research Objectives Investigate Investigate Multi-agent processing solutions Multi-agent processing solutions Multi-agent communications Multi-agent communications Provide pragmatic solutions featuring Provide pragmatic solutions featuring Distributed agent processing Distributed agent processing Small hardware footprint Small hardware footprint Automatic load balancing Automatic load balancing Fault tolerance Fault tolerance Inter-agent communication between diverse agents Inter-agent communication between diverse agents

4. Blue Bear Systems Research Clustering Approaches for Multi-Agent Systems Clustering maps naturally to multi-agent processing Clustering maps naturally to multi-agent processing Two approaches considered Two approaches considered Beowulf Beowulf Designer controls parallelism Designer controls parallelism Libraries such as PVM and MPI provide communications and parallelism Libraries such as PVM and MPI provide communications and parallelism OpenMosix OpenMosix Single-system image approach Single-system image approach Provides load balancing, process migration, fault tolerance, reconfiguration Provides load balancing, process migration, fault tolerance, reconfiguration Parallelism transparent to designer (almost) Parallelism transparent to designer (almost)

5. Blue Bear Systems Research Agent Hardware Autonomous mobile applications limit space, power, etc. Autonomous mobile applications limit space, power, etc. Two technologies under investigation Two technologies under investigation Field Programmable Gate Arrays (FPGA) Field Programmable Gate Arrays (FPGA) Provide flexibility of software within parallel, high speed hardware Provide flexibility of software within parallel, high speed hardware Use as agents studied by University of Kent Use as agents studied by University of Kent Miniature clusters Miniature clusters Miniature Beowulf/OpenMosix System Miniature Beowulf/OpenMosix System

6. Blue Bear Systems Research Miniature Clusters Power of embedded processors increasing Power of embedded processors increasing Feasible to build a miniaturised cluster based on COTS components Feasible to build a miniaturised cluster based on COTS components Systems such as XBoard and Gumstix provide A complete system Systems such as XBoard and Gumstix provide A complete system

7. Blue Bear Systems Research Agent Communication Framework #1 Agent communication between disparate agent difficult Agent communication between disparate agent difficult Agent Communication Languages (ACL) developed to address this Agent Communication Languages (ACL) developed to address this Wrap internal representation of information in a agent neutral form Wrap internal representation of information in a agent neutral form Little support currently within Soar Little support currently within Soar Developed communication framework and ACL wrapper for Soar Developed communication framework and ACL wrapper for Soar

8. Blue Bear Systems Research Agent Communication Framework #2 Marshaller Other Agent Agent Wrapper Java Agent Agent Wrapper Soar Agent Agent Wrapper Remote Object (CORBA) Agent Wrapper Other Marshallers Embedded Script Agent Wrapper

9. Blue Bear Systems Research Prototype Soar Implementation Multi-agent Soar Multi-agent Soar Send and receive complete substructures of working memory to other agents Send and receive complete substructures of working memory to other agents Locate agents in the external environment that are available for communications Locate agents in the external environment that are available for communications Consistent philosophy in the use of the Soar i/o link structures Consistent philosophy in the use of the Soar i/o link structures

10. Blue Bear Systems Research Soar Agent Communication #1 Receiving Receiving I6 I8 ^input-link I9 ^agents T1 B1 ^bill ^tom I6 I8 ^input-link I9 ^agents T1 B1 ^bill ^tom S2 ^sensor ^position ^finished 6 true

11. Blue Bear Systems Research Soar Agent Communication #2 Transmitting Transmitting Similar to receiving Similar to receiving New ^agents attribute under output link New ^agents attribute under output link Agent adds the names of the agents it wishes to communicate to below this Agent adds the names of the agents it wishes to communicate to below this

12. Blue Bear Systems Research Example Problem Road search application Road search application Generate a plan for searching a network of roads with a finite number of search assets (UAVs) Generate a plan for searching a network of roads with a finite number of search assets (UAVs) Input: Input: position and direction of target ground vehicle position and direction of target ground vehicle Output: Output: guidance commands to search assets guidance commands to search assets

13. Blue Bear Systems Research Algorithm Architecture #1 Original algorithm was a single soar agent Original algorithm was a single soar agent Large and complex Large and complex Unverifiable Unverifiable Current algorithm Current algorithm Uses work in agent hardware architectures to produce distributed solution Uses work in agent hardware architectures to produce distributed solution Agents written in verifiable soar as defined by Malvern Agents written in verifiable soar as defined by Malvern Partitions problem into a number of simple communicating agents Partitions problem into a number of simple communicating agents Each agent individually verifiable? Each agent individually verifiable?

14. Blue Bear Systems Research Algorithm Architecture #2

15. Blue Bear Systems Research Soar Search Agent Single agent is relatively simple written in verifiable soar Single agent is relatively simple written in verifiable soar Agent knows how to perform a single task Agent knows how to perform a single task From an initial position and direction, define search path until next junction From an initial position and direction, define search path until next junction At a junction, start more search agents with the junction as their initial position At a junction, start more search agents with the junction as their initial position Builds up road network ‘recursively’ Builds up road network ‘recursively’

16. Blue Bear Systems Research Other Agents/Processes #1 Search agent manager Search agent manager Maintains search agent processes Maintains search agent processes Monitors load balancing and fault conditions Monitors load balancing and fault conditions Search planner Search planner Receives search segments from search agents Receives search segments from search agents Gradually builds up a complete map Gradually builds up a complete map

17. Blue Bear Systems Research Other Agents/Processes #2 Asset manager Asset manager Receives connected road segments from search planner Receives connected road segments from search planner Allocates roads to the search assets Allocates roads to the search assets Asset controller Asset controller On-board the UAV On-board the UAV Maintains list of roads to search as series of waypoints Maintains list of roads to search as series of waypoints Two modes: Two modes: Loiter if no new roads to search Loiter if no new roads to search Search roads via waypoint following Search roads via waypoint following

18. Blue Bear Systems Research Demonstration Overview Heterogeneous network of PCs for search agents and other processes Heterogeneous network of PCs for search agents and other processes Search assets are two 6DOF UAV simulations Search assets are two 6DOF UAV simulations Real time Real time 3D visualisation of UAV and terrain 3D visualisation of UAV and terrain