KQML as an Agent Communication LanguageTim Finin, Yannis Labrou, James Mayfield

Overview(1)Personal assistant is a agent?_?Interaction and interoperation is desirableIntelligent interaction is knowledge sharing that includes bothmutual understanding of knowledgecommunication of that knowledge

Overview(2)Effective interaction and interoperation requires three components a common languagea common understanding of the knowledge exchangedthe ability to exchange whatever is included in aboveKnowledge Sharing Effort consortium

Overview(3)This paper will presentThe Approach and Solutions of the KSECommunication Language and their Desired FeaturesKnowledge Query and Manipulation Language(KQML)Other Communication LanguagesConclusions

The Approach of the KSE(1)Figure1.(p.293)Components of interoperating software agents are grouped into:Representation componentsCommunication componentsComponents not directly related to shared understanding

The Approach of the KSE(2)Mutual understanding can be divided into two subproblems:Translating from one representation language to anotherSharing the semantic content of the represented knowledge among different application

The Approach of the KSE(3)Communication is a threefold problem involving knowledge ofInteraction protocolhigh-level strategy pursued by the agentCommunication languagewhat the content of the communication isTransport protocolTCP, SMTP, HTTP

The Approach of the KSE(4)Other components to help the agent carry out its businessReasoningMeta-knowledgePlanning activitiesModeling other agents

The Approach of the KSE(5)KSE is organized around the three working groupsInterlingua(KIF)Common language for expressing the content Shared Reusable Knowledge Bases(Ontolingua)Repository for sharable ontologies and toolsExternal Interfaces(KQML)Run-time interaction in knowledge-based system

The Solutions of the KSE(1)Knowledge Interchange FormatKIF is a prefix version of first order predicate calculus with extensions to support nonmonotonic reasoning and definitionsOntologies and OntolinguaOntolingua is the framework for the development of ontologiesKQML

The Solutions of the KSE(2)Knowledge Interchange Format(KIF) The Language description includes both a specification for it's syntax and one for its semanticsexamples(salary 026-40-9152 grommets 36000)(>(*(width chip1)(length chip1))(*(width chip2)(length chip2)))(=> (and(real-number ?x)(even-number ?n)) (>(expt ?x ?n)0))(interested joe '(salary ,?x,?y,?z))(progn (fresh-lint t)(print "Hello!")(fresh-line t))

The Solutions of the KSE(3)Ontologies and OntolinguaThe SRKB is building knowledge-based software reused as off-the-shelf technologyOntologies are written in KIF, using the definitional vocabulary of Ontolingua (classes, function, object constants, and rules to constrain the interpretation)

The Solutions of the KSE(4)KQMLKQML messages are opaque to the content they carryPerformatives define the permissible actions that agents may attempt in communicating with each otherAn environment of KQML speaking agents may be enriched with special agents, called facilitators

Communication Languages and their Desired Features(1)FormContentSemanticsImplementationNetworkingEnvironmentReliability

Communication Languages and their Desired Features(2)FormDeclarative Syntactically simpleReadable by peopleConciseLinearextensible

Communication Languages and their Desired Features(3)ContentCommunication languageCommunicative actsContent languageFacts about the domain

Communication Languages and their Desired Features(4)SemanticsUnambiguousCanonical formModel of communication

Communication Languages and their Desired Features(5)ImplementationEfficientBoth in speed and bandwidthInterfaceEasy to useAmenableTo handle partial implementation

Communication Languages and their Desired Features(6)NetworkingPoint to pointMulti-castBroadcastSynchronousAsynchronous

Communication Languages and their Desired Features(7)EnvironmentDistributedHeterogeneousDynamic

Communication Languages and their Desired Features(8)ReliabilityReliable communicationSecure communicationRobust to malformed messages

KQMLA Description of KQMLFacilitators, Mediators, and the Environment of KQML AgentsEvaluation of KQML as an Agent Communication LanguageApplication of KQML

A Description of KQML(1)The KQML language can be thought of as consisting of three layersThe content layerActual content of the messageThe message layerInteractions with KQML-speaking agentThe communication layerLower level communication parameters

A Description of KQML(2)Table 1.(p.303)Figure 2.(p304)A BA CA D

Facilitators,Mediators and the Environment of KQML AgentsFacilitators, MediatorsFigure 3.(p.305)Figure 4.(p.306)Figure 5.(p.306)Figure 6.(p.307)Figure 7.(p.307)EnvironmentKQML API, register, facilitator.domain

Evaluation of KQML as an ACL(1)FormContentSemanticsImplementationNetworkingEnvironmentreliability

Evaluation of KQML as an ACL(2)FormDeclarative(performatives)Linear(Lisp-like syntax)Easy to read, parse, and convert to otherSimple and extensible

Evaluation of KQML as an ACL(3)ContentThe content layerThe message layerProviding a small set of primitives thereby requiring overloading at the content levelProviding an extensive set of acts, where inevitably acts will overlap one another and/or embody fine distinctions The communication layer

Evaluation of KQML as an ACL(4)SemanticsStill an open issueFor now there are only natural language descriptions of the intended meaning of the performatives and their use(protocol)

Evaluation of KQML as an ACL(5)ImplementationContent-independent message router FacilitatorHandler functionsKQML speaking interfaceEfficiency(message sizes, substantial fraction of symbol lookup and string duplication)

Evaluation of KQML as an ACL(6)NetworkingCommunicate directly with other agentsBroadcast their messagesSolicit the services of facilitatorsSynchronous-asynchronous interactionsBlocking-nonblocking message sending

Evaluation of KQML as an ACL(7)EnvironmentAny transport protocol(TCP/IP, HTTP,etc)KQML messages are oblivious to contentFacilitators can cooperate with other knowledge discovery applications available in the World Wide Web

Evaluation of KQML as an ACL(8)ReliabilityNo decision has been made on whether the issues of security and authentication should be handled at the transport protocol level or at the language levelNew performatives can be introduced at the language level(encryption, error, sorry)

Applications of KQMLIntegration of design and engineering tools ARPA Rome Lab Planning InitiativeTechnology integrationSIPE agent, Common Lisp scheduler, toolsCoBASE, SIMS, LIMAgent-Based Software Integration KQML implementation ACL(Stanford)KQML URL for the World Wide Web

Other Communication LanguageAgent-Oriented ProgrammingTheoreticalIntentional(beliefs,capablilities,etc)AOP paradigm need to be provenTelescriptAppliedDo NOT communication(predefined script)

ConclusionsThere is no silver bullet for the problem of knowledge sharing KSE approach Translating between representations(KIF)Sharing the semantic content of the knowledge that is represented(Ontolingua)Communication attitudes about the shared knowledge(KQML)Facilitators