KQML as an Agent Communication Language Tim Finin, Yannis Labrou, James Mayfield

Overview(1) Personal assistant is a agent … ?_? Interaction and interoperation is desirable Intelligent interaction is knowledge sharing that includes both mutual understanding of knowledge communication of that knowledge

Overview(2) Effective interaction and interoperation requires three components a common language a common understanding of the knowledge exchanged the ability to exchange whatever is included in above Knowledge Sharing Effort consortium

Overview(3) This paper will present The Approach and Solutions of the KSE Communication Language and their Desired Features Knowledge Query and Manipulation Language(KQML) Other Communication Languages Conclusions

The Approach of the KSE(1) Figure1.(p.293) Components of interoperating software agents are grouped into: Representation components Communication components Components 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 another Sharing the semantic content of the represented knowledge among different application

The Approach of the KSE(3) Communication is a threefold problem involving knowledge of Interaction protocol high-level strategy pursued by the agent Communication language what the content of the communication is Transport protocol TCP, SMTP, HTTP

The Approach of the KSE(4) Other components to help the agent carry out it ’ s business Reasoning Meta-knowledge Planning activities Modeling other agents

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

The Solutions of the KSE(1) Knowledge Interchange Format KIF is a prefix version of first order predicate calculus with extensions to support nonmonotonic reasoning and definitions Ontologies and Ontolingua Ontolingua is the framework for the development of ontologies KQML

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 semantics examples (salary 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 Ontolingua The SRKB is building knowledge-based software reused as off-the-shelf technology Ontologies 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) KQML KQML messages are opaque to the content they carry Performatives define the permissible actions that agents may attempt in communicating with each other An environment of KQML speaking agents may be enriched with special agents, called facilitators

Communication Languages and their Desired Features(1) Form Content Semantics Implementation Networking Environment Reliability

Communication Languages and their Desired Features(2) Form Declarative Syntactically simple Readable by people Concise Linear extensible

Communication Languages and their Desired Features(3) Content Communication language Communicative acts Content language Facts about the domain

Communication Languages and their Desired Features(4) Semantics Unambiguous Canonical form Model of communication

Communication Languages and their Desired Features(5) Implementation Efficient Both in speed and bandwidth Interface Easy to use Amenable To handle partial implementation

Communication Languages and their Desired Features(6) Networking Point to point Multi-cast Broadcast Synchronous Asynchronous

Communication Languages and their Desired Features(7) Environment Distributed Heterogeneous Dynamic

Communication Languages and their Desired Features(8) Reliability Reliable communication Secure communication Robust to malformed messages

KQML A Description of KQML Facilitators, Mediators, and the Environment of KQML Agents Evaluation of KQML as an Agent Communication Language Application of KQML

A Description of KQML(1) The KQML language can be thought of as consisting of three layers The content layer Actual content of the message The message layer Interactions with KQML-speaking agent The communication layer Lower level communication parameters

A Description of KQML(2) Table 1.(p.303) Figure 2.(p304) A  B A  C A  D

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

Evaluation of KQML as an ACL(1) Form Content Semantics Implementation Networking Environment reliability

Evaluation of KQML as an ACL(2) Form Declarative(performatives) Linear(Lisp-like syntax) Easy to read, parse, and convert to other Simple and extensible

Evaluation of KQML as an ACL(3) Content The content layer The message layer Providing a small set of primitives thereby requiring overloading at the content level Providing 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) Semantics Still an open issue For 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) Implementation Content-independent message router Facilitator Handler functions KQML speaking interface Efficiency(message sizes, substantial fraction of symbol lookup and string duplication)

Evaluation of KQML as an ACL(6) Networking Communicate directly with other agents Broadcast their messages Solicit the services of facilitators Synchronous-asynchronous interactions Blocking-nonblocking message sending

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

Evaluation of KQML as an ACL(8) Reliability No decision has been made on whether the issues of security and authentication should be handled at the transport protocol level or at the language level New performatives can be introduced at the language level(encryption, error, sorry)

Applications of KQML Integration of design and engineering tools ARPA Rome Lab Planning Initiative Technology integration SIPE agent, Common Lisp scheduler, tools CoBASE, SIMS, LIM Agent-Based Software Integration KQML implementation ACL(Stanford) KQML URL for the World Wide Web

Other Communication Language Agent-Oriented Programming Theoretical Intentional(beliefs,capablilities,etc … ) AOP paradigm need to be proven Telescript Applied Do NOT communication(predefined script)

Conclusions There 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