Multi-Agent Systems - Architecture Craig Thompson Object Services - PowerPoint PPT Presentation

Multi-Agent Systems - Architecture Craig Thompson Object Services and Consulting, Inc. (OBJS) OBJS Agents - 1

OUTLINE • Vision • Agent Reference Architecture • Agent Services • Applications • Contributions & Directions OBJS Agents - 2

VISION – EVERYTHING IS ALIVE orders & observations & subscriptions recommendations Need Any I see a fuel! threats? tank! OBJS Agents - 3

AGENT REFERENCE ARCHITECTURE What is a Reference Architecture – a meta-architectural blueprint for a family of concrete architectures that may appear in implemented systems, providing architectural views, a collection of the component parts of the architecture, how they can fit together, and any constraints on how they fit. – a litmus test for a good reference architecture is that it covers actual systems and provides a way to reason about missing pieces, sub-architectures that make sense, interdependencies of parts, and how the architecture relates to other nearby architectures. What should an Agent Reference Architecture do? – help people understand the scope and value-added of agent systems so they can realize their potential more quickly (agents for the masses) – explain • how agent architectures solve application domain problems • how agent systems complement OMA, HLA, Web, DBMS • how to insure systemic properties of agent systems – scalability, survivability, … – identify • principle components of agent systems, their interfaces and their interactions • missing components • what parts of the architecture already exist in COTS and GOTS, what parts are already prototyped, and what parts are still needed. • candidate standards and a roadmap for adoption • research issues (e.g., agent control, agent interoperability) OBJS Agents - 4

Characteristics of Agents Agents dynamically adapt Agents coordinate to and learn about and negotiate to achieve their environment common goals Intelligent Information social social personality Agents personality Agents Adaptive Adaptive Cooperative Cooperative to uncertainty and change self-organizing delegation Autonomous Autonomous Mobile Mobile Interoperate Interoperate proactive Agents move Agents interoperate Agents are goal directed to where they with humans, other, and act on their are needed legacy systems, and own performing information sources tasks on your behalf OBJS Agents - 5

What are people saying about agents? • software that acts on a human’s behalf to provide some service or function in an intelligent manner • modular software that exhibits some of these properties: autonomy, mobility, intelligence • objects with an attitude -- component software constructed according to certain principles and/or mechanisms, e.g., objects that use an ACL to communicate, objects that make use of a planner, … • networked society where every software artifact, information source, and device is connected and running in parallel. Connect the $40B worth of DoD equipment that currently only interoperates with one or two other components, permitting better knowledge sharing. A process improvement in factory 1 is broadcast immediately to factories 2 .. N • intelligent automation-- application connectivity where networks of agents self-organize at run-time. Reduce the 60% of time in command and control systems spent manipulating stovepipes; incrementally replace stovepipes. • humans and agents connect to the agent grid anytime from anywhere and get the information and capability they need. Enable teams led by humans and staffed by agents. • agent-enable object and web applications to reconfigure as new data and function is added to the system. Add capability modularly. Stable, scaleable, evolvable, reliable, secure, survivable, ... • Scale to millions of agents so agents are pervasive and information and computation is not restricted to machine or organization boundaries. • Survivable so if one agent goes down, another takes its place; OBJS Agents - 6

Relevant Theories View • speech acts, conversations/dialogs • ontologies • KBMS • distributed AI • architecture description languages • patterns and protocols • OO middleware service architectures (OMA/ORB) • web architectures • workflow • dynamic DBMS • simulation • network management, QoS • planning & case-based reasoning • learning • game theory • economic markets • ... OBJS Agents - 7 * = Architecture WG in Pittsburg

What is an Agent? deconstructionist view: agents augment objects with additional capabilities    Object Component Agent ? • state • reflection • agent comm. language • TBD • behavior • packaging • process inside • encapsulation • serialization • mobility • inheritance • repository • goals, planning, rules • autonomous • ontologies • collaborative/teams OBJS Agents - 8

FIPA Abstract Architecture Foundation for Intelligent Physical Agents -- http://www.fipa.org/specs/fipa00001 • Agent Abstract Architecture  goal is interoperability – Agent API via Agent Communication Language (ACL) components • addressing • publish & subscribe & • content language semantics interfaces – Agent Services • Encoding/Parsing Service – how messages are encoded • Message Transport Service – how messages are sent, guarantees, survivability • Directory Service – register agent description, discover agents • Borrows from other areas – User Interface(s) – optional – GUI, natural language , … – Security services Interfaces insulate components. – Directory services We should be able to add or change a component. – Distributed communications – asynchronous, intermittent – Platform & comm. – host abstract machine, environment • Candidates not yet in current abstract architecture – Agent lifecycle – Mobility – Domains – Conversational policies – Ontologies – representation of state OBJS Agents - 9

Agent Ontology View (aka Functional/Compositional View) Architecture Principle: separation of concerns deconstructionist view - what can you take away and still have an agent system policy*, management ALP, HLA, IA GRID federates AGENT SYSTEM • resource dial • single vs. multi-agent heterogeneous* • computing environ. systemic common services ensembles societies agent properties & kinds • agent systems grid features • # of agents* • closed vs. open, • communication • ACLs • teams, peers, communities of interest capability distribution • content languages • computation capability contracting, messaging svcs* • ontologies autonomous • org. responsibility • by role in system agent life cycle* - start, stop, • policies decentralized* • roles, capabilities, • information agent control*, coordination*, I*3 checkpoint, • services OMG • mutual beliefs • data sources BADD multi-agent synchronization name service** • open world • hierarchy* • cooperation, competition JTF • interface agent AICE event monitoring scalability* assumption • conversational Jini • NL leasing, compensation • fisheye view policies* catalog services*, adaptation, evolution* • task agent registry/repository* via market model, ... licensing & cost • web agent register*, • middleware agent offer/accept/decline • mobile agent , itinerary publish*, subscribe* • social, personality, mobility** trading*, matchmaking, ONTOLOGY** motivation, forgetting advertising*, negotiating*, • ontolingua, OKBC • intelligent agent brokering*, yellow pages* • metadata representations security** • interests, locations, secure*, trust IA authenticate* availability, capability, speech acts*: ACL* - encrypt price/cost KQML, FIPA ACL, OAA access control lists* • XML and web object models ICL survivability firewall* CIA model agent suspects transactions planning* infrastructure • reactive* persistence* EDCS evolvability primitives • goal interactions* query, profile (of metadata)* • reflection • discrete vs continuous* data fusion • serialization missing • constraints replication* reliable* • threads • views • iterative, revision groups • interceptors • MOP • workflow multicast • proxies (scarce) resource mgmt*, • filters Quorum QoS* allocate*, deallocate*, • multicast • accuracy learning monitor*, • wrappers • priorities • by example local, global optimization, More common services • legacy sys • ... load balancing*, negotiation • data sources instrumenting, logging for resources* caching time-constrained* scheduling content languages queuing * = Architecture WG in Pittsburg • KIF, FOL, IDL, time, geo-location DDB routing, rerouting * = Control WG in Pittsburg rules, constraints RDF pedigree, drill down * = Interoperability WG in Pittsburg planning* translation* red = Sun Jini property list OBJS Agents - 10 ... green = other DARPA programs versioning, config