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KQML - A Language and Protocol for Knowledge and Information Exchange

Reference: Finin, Fritzson, McKay, McEntire (1994). AAAI Technical Report WS-94-02, Workshop on Knowledge-Based Collaboration Systems. Source file: WS94-02-007.pdf. URL

Summary

This is one of the canonical early KQML papers, describing the Knowledge Query and Manipulation Language as both a message format and a message-handling protocol for run-time knowledge sharing among intelligent agents. Developed as part of the ARPA Knowledge Sharing Effort (KSE), KQML is presented as an enabling technology for building large-scale, sharable, reusable knowledge bases and for letting independently developed systems interoperate at the knowledge level rather than at the level of raw RPC or ad-hoc protocols.

The paper introduces the core architectural commitments of KQML: an extensible set of performatives (reserved speech-act-like operations that agents perform on each other’s knowledge and goal stores), a three-layer message structure (content, message/communication, and communication mechanics), and a special class of facilitator agents that coordinate interactions and provide services such as brokering, recruitment, and content-based routing. Performatives fall into seven categories (basic query, multi-response query, response, generic informational, generator, capability-definition, networking) including ask-one, ask-all, tell, untell, achieve, subscribe, advertise, broker, recommend, and recruit.

The authors sketch KQML’s semantics informally in terms of effects on an agent’s belief and intention stores (e.g., tell(S) is an assertion by the sender that S is in its virtual belief store; achieve(S) asks the recipient to add S to its intention store), and note ongoing work on formal semantics via definite clause grammars and on interoperability with KIF and Ontolingua ontologies.

Key Ideas

  • KQML as both message format and message-handling protocol; focused on pragmatics, secondarily on semantics.
  • Three-layer message structure: content, communication/message, communication mechanics.
  • Extensible performative set organized into seven categories.
  • Facilitator agents: brokers, matchmakers, recruiters, content-based routers.
  • Synchronous, asynchronous, streaming, and subscription interaction protocols.
  • Performatives as speech-act-like operations on agents’ belief and goal stores.
  • Integration with KIF for content and shared ontologies for semantic grounding.
  • Part of the ARPA Knowledge Sharing Effort (KSE): Interlingua, KRSS, SRKB, External Interfaces working groups.

Connections

Conceptual Contribution

Tags

#kqml #acl #speech-acts #agent-communication #multi-agent-systems #ontologies

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