Authors:
Susumu Yamasaki
and
Mariko Sasakura
Affiliation:
Department of Computer Science, Okayama University, Tsushima-Naka, Okayama, Japan
Keyword(s):
Abstract Consultation, Causal Analysis, Abstract State Machine, Model Theory in Database.
Abstract:
This paper deals with consultation as a role of consultant like a teacher in a virtual reality class for lessons. The consultation subject is taken in causal analysis and database design to conceive causal relation. The causal analysis is abstracted into effectiveness which is caused by requisites and prohibitions for effects. The database design is represented as recursive Backus-Naur Form for structural expressions. Then abstract consultation can be regarded as a function to transform effectiveness into recursive representation. The sense or meaning of such abstract consultation may be a semantics of conditioned formulas in modal logic. The modal logic is formulated in this paper, by extending postfix modality for name of database design as well as greatest fixed point operator for denoting an equilibrium state set where the transformation of effectiveness with prefix modality to design with postfix modality may be available. The conditioning of formulas is given by a state set so
that the formula may be considered in terms of propositional base. As regards recursive representations in Backus-Naur Form for database design, model theory is established in 3-valued domain, for the sense of strong negation in accordance to prohibitions influencing effectiveness. Some fixed point is taken for the mapping associated with recursive representations, where the mapping is related to formations of models over 3-valued domain. The fixed point model can be seen as means of retrieval. However, because the mapping is generally a nonmonotonic function whose fixed point semantics is not always available, we have another method to adopt negation as failure for strong negation such that the model of a given recursive representation as database is always guaranteed if the representation takes a restricted form. Abstract consultation to effectiveness for database design is thus formulated, with model theory in database representations.
(More)