A Semantic Metanetwork

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A Semantic Metanetwork
Vagan Terziyan University of Jyvaskyla,
Finland e-mail vagan_at_it.jyu.fi http//www.cs.jyu.
fi/ai/vagan/index.html
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Creating and Managing Knowledge According to
Different Levels of Possible Context - are among
the basic abilities of an intelligent agent
Metacontexts
Meta-metaknowledge
Contexts
Metaknowledge
Data
Knowledge
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Contents

• Metasemantics
• Metasemantic Network
• Metasemantic Algebra of Contexts

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Metasemantics
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Semantic Predicate
Lk
Aj
Ai
Relation (i ? j)
Ai
Property (i j)
Lk
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State of a Semantic Net
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Structure of the Metasemantics
Metasemantics
Production Rules
Temporal Rules
Semantic Rules
Semantic Network
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Read more about Metasemantics in
Terziyan V., Multilevel Models for Knowledge
Bases Control and Their Applications to Automated
Information Systems, Doctor of Technical Sciences
Degree Thesis, Kharkov State Technical University
of Radioelectronics, 1993.
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Metasemantic Networks
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A Metasemantic Network
Metasemantic Network (Semantic Metanetwork) is
considered formally as the set of semantic
networks, which are put on each other in such a
way that links of every previous semantic network
are in the same time nodes of the next network
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An Example of a Semantic Metanetwork
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How it Works

• In a Semantic Metanetwork every higher level
  controls semantic structure of the lower level.
• Simple controlling rules might be, for example,
  in what contexts certain link of a semantic
  structure can exist and in what context it should
  be deleted from the semantic structure.
• Such multilevel network can be used in an
  adaptive control system which structure is
  automatically changed following changes in a
  context of the environment.
• The algebra for reasoning with a semantic
  metanetwork is also developed.

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Published and Further Developed in
Terziyan V., Multilevel Models for Knowledge
Bases Control and Their Applications to Automated
Information Systems, Doctor of Technical Sciences
Degree Thesis, Kharkov State Technical University
of Radioelectronics, 1993.
Terziyan V., Puuronen S., Reasoning with
Multilevel Contexts in Semantic Metanetworks, In
P. Bonzon, M. Cavalcanti, R. Nossun (Eds.),
Formal Aspects in Context, Kluwer Academic
Publishers, 2000, pp. 107-126.
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Metasemantic Algebra of Contexts
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Metasemantic Algebra A Semantic Predicate
Semantic predicate describes a piece of knowledge
(relation or property) by the expression if
there is knowledge that a relation with name Lk
holds between objects Ai and Aj
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Example of Knowledge
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Semantic Operations Inversion
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Semantic Operations Negation
P(ltMarygt, ltto_lovegt, ltTomgt) false, it is the
same as P(ltMarygt, ltnot_to_lovegt, ltTomgt) true.
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Semantic Operations Composition
If it is true P(ltMarygt, ltto_be_married_withgt,
ltTomgt) and P(ltTomgt, ltto_have_mothergt,
ltDianagt), then it is also true that P(ltMarygt,
ltto_have_mother-in-lawgt, ltDianagt).
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Semantic Operations Intersection
ltto_give_birth_togt ltto_take_care_ofgt
ltto_be_mother_ofgt.
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Semantic Operations Interpretation
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Interpreting Knowledge in a Context
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Example of Interpretation
The interpreted knowledge about the relation
between A1 and A3 taking all contexts and
metacontexts into account is as follows
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Decontextualization
Suppose that your colleague, whose context you
know well, has described you a situation. You use
knowledge about context of this person to
interpret the real situation. Example is more
complicated if several persons describe you the
same situation. In this case, the context of the
situation is the semantic sum over all personal
contexts.
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Context Recognition
Suppose that someone sends you a message
describing the situation that you know well. You
compare your own knowledge with the knowledge you
received. Usually you can derive your opinion
about the sender of this letter. Knowledge about
the source of the message, you derived, can be
considered as certain context in which real
situation has been interpreted and this can help
you to recognize a source or at least his
motivation to change the reality.
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Lifting (Relative Decontextualization)
This means deriving knowledge interpreted in some
context if it is known how this knowledge was
interpreted in another context.
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Published and Further Developed in
Terziyan V., Multilevel Models for Knowledge
Bases Control and Their Applications to Automated
Information Systems, Doctor of Technical Sciences
Degree Thesis, Kharkov State Technical University
of Radioelectronics, 1993.
Terziyan V., Puuronen S., Reasoning with
Multilevel Contexts in Semantic Metanetworks, In
P. Bonzon, M. Cavalcanti, R. Nossun (Eds.),
Formal Aspects in Context, Kluwer Academic
Publishers, 2000, pp. 107-126.