Object Services and Consulting, Inc.

StrawmanAgent Reference Architecture

(DARPA ISO coABS Program - Draft 11-30-98)

Craig ThompsonObject Services and Consulting, Inc. (OBJS)thompson@objs.com, http://www.objs.com

Object Services and Consulting, Inc.

Agent Reference ArchitectureRequirements

Target operational requirements:

• Networked society where everything is alive -- every software artifact, information source, and device is connected and running in parallel. 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.

• Intelligent automation -- easier application connectivity where networks of agents self-organized at run-time. Reduce the 60% of time in command and control systems spent manipulating stovepipes; incrementally replace stovepipes.

• Connect the $40B worth of DoD equipment that currently only interoperates with one or two other components, permitting better knowledge sharing. Another example is a process improvement in factory 1 is broadcast immediately to factories 2..N.

• Agent-enable object and web applications to reconfigure as new data and function is added to the system. Scale to millions of agents so agents are pervasive and information and computation is not restricted to machine or organization boundaries; if one agent goes down, another takes its place; add capability modularly; stable, scaleable, evolvable, reliable, secure, survivable, ...

Object Services and Consulting, Inc.

AdaptiveAdaptiveto uncertainty and change

Agents are goal directedand act on theirown performing

tasks on your behalf

Agents coordinate and negotiate to achieve

common goals

Agents moveto where they

are needed

AutonomousAutonomousproactive

MobileMobile InteroperateInteroperate

Agents interoperatewith humans, other, legacy systems, and information sources

Agents dynamically adaptto and learn abouttheir environment

CooperativeCooperativeself-organizing

delegation

socialpersonality

socialpersonality

Characteristics of Agents

Object Services and Consulting, Inc.

Agents + the Global Software Grid

System Concept View

Server

DataService

AA

A

A

A

AA

A

A

A

A

A

A

A

AA

A

A

A

AA

A

A

A

A

A

A

A

A

A

AA

Server

ComponentLibrary

Server

DataService

Server

ComponentLibrary

• speech acts, conversations/dialogs• ontologies• game theory• economic markets• patterns and protocols• planning & case-based reasoning• learning• KBMS• workflow• dynamic DBMS• simulation• architecture description languages• distributed AI• component technology• Web architectures• frameworks (Jini)• OO middleware services (OMA/ORB)• network management and QoS

Relevant Theory

Object Services and Consulting, Inc.

agent properties & kinds• communication

capability• computation capability• by role in system

• information agent• data sources

• interface agent• NL• fisheye view

• task agent• web agent• middleware agent

• mobile agent, itinerary• social, personality,

motivation, forgetting• intelligent agent

distributionmessaging svcs*agent life cycle* - start, stop,

checkpoint, name service**event monitoringleasing, compensationcatalog services*, registry/repository* register*, offer/accept/decline publish*, subscribe* trading*, matchmaking, advertising*, negotiating*, brokering*, yellow pages*security** authenticate* encrypt access control lists* firewall* CIA model agent suspectstransactionspersistence*query, profile (of metadata)*data fusionreplication* groups multicast(scarce) resource mgmt*,

allocate*, deallocate*, monitor*,

local, global optimization, load balancing*, negotiation for resources*

schedulingtime, geo-locationrules, constraintsplanning*property listversioning, config

Agent Architecture Details

speech acts*: ACL* - KQML, FIPA ACL, OAA ICL

planning*• reactive*• goal interactions*• discrete vs continuous*• constraints• iterative, revision• workflow

systemicgrid features

common services

AGENT SYSTEM• single vs. multi-agentAGENT SYSTEM• single vs. multi-agent

ensembles• # of agents*• teams, peers,

contracting,• org. responsibility• roles, capabilities,• mutual beliefs• hierarchy*• conversational

policies*

scalability*

policy*, management• resource dial

survivability

evolvability

reliabile*

licensing & cost

QoS*• accuracy• priorities

GRID

time-constrained*

control*, coordination*,multi-agent synchronization• cooperation, competition

adaptation, evolution*via market model, ...

federates

infrastructureprimitives• reflection• serialization• threads• interceptors• proxies• filters• multicast • wrappers

• legacy sys• data sources

ONTOLOGY**• ontolingua, OKBC• metadata representations

• interests, locations, availability, capability, price/cost

• XML and web object models

I*3BADDAICE

IA

EDCS

Quorum

OMGJTFJini

ALP, HLA, IA

Architecture Principle: separation of concernsdeconstructionist view - what can you take away

and still have an agent system

secure*, trust

societies• closed vs. open,

communities of interest

learning• by example• ...

mobility**

heterogeneous*• computing environ. • agent systems• ACLs• content languages• ontologies• policies• services• open world

assumption

autonomousdecentralized*

* = Architecture WG in Pittsburg* = Control WG in Pittsburg* = Interoperability WG in Pittsburgred = Sun Jini green = other DARPA programs

content languages• KIF, FOL, IDL,

RDF

missing• views• MOP

More common services

instrumenting, loggingcachingqueuingrouting, reroutingpedigree, drill downtranslation*...

DDB

Object Services and Consulting, Inc. Architecture Issues

• What are agents? - code and data packets that are autonomous, adaptive, cooperative, mobile, interoperable … We want all these properties in future agent-based systems. We need experience building systems with these properties.

• Pervasiveness - How do we insure that the architecture stays lite-weight for wide-spread adoption. • Embracing heterogeneity - We must piggyback agent systems on already pervasive infrastructure like ORBs, the

Web, email, and DBMS systems. We must identify the specific kinds of heterogeneity we want agent system architectures to support.

• Separation of concerns• agent-agent separation - can agents access each other’s state directly• agent-service separation - do agents implement the long list of services that the grid provides or is that done via

underlying component-based middleware? • grid-agent separation - agents are autonomous but they cooperate and compete for resources within the

software grid. The grid provides some global systemic properties and some basic shared services. Is there an explicit grid or is it implicit in the way agents interact with each other? Are some “services” (like planning) optionally distributed into agents or are they available from the grid’s planing service? Can new services be autoloaded into a grid that does not have them?

• Semantic interoperability, ontology - do ontologies scale? How do they extend class libraries?• Licensing - Agents, data sources, and component software need an economic model so broad communities can get

value from them. A model of licensing might be critical to success in the large.• Agent communication language (ACL) - Is the ACL compositional and extensible so one can define new speech acts

from existing ones? How many speech acts is enough? 20 or 5000?• Control points - where are the control points where different control algorithms might be substituted into the

architecture• Grid federation issues - How are software grids federated - flat versus hierarchical models? If different grids contain

different policy choices or different services, how does that affect agents communicating across grid boundaries? Can we add new services and -ilities to a grid once it is deployed? how transparent is addition or subtraction of services and ilities

• Coordination - Insure Agent Reference Architecture augments DARPA ISO ATAIS architecture. Provide template for next generation unified OMG, FIPA, and W3C agent standards. Insure that reference implementations (toolkits) exist and are widely available.