Jun'ichi Toyoda

Some considerations on fuzzy automata

In this paper, we show: The threshold of fuzzy automata can be changed arbitrarily. The fuzzy sets of input sequences characterized by fuzzy automata constitute a distributive lattice, and the complement of the fuzzy set can be characterized by an optimistic fuzzy automaton.

A cognitive load application in tutoring

Research on intelligent tutoring systems has mainly concentrated on how to reduce a cognitive load which a student will bear in learning a domain. This load reduction approach contributes to facilitating his/her learning. However the approach often fails to reinforce the students comprehension and retention. Another approach to tutoring is to apply a load to him/her purposefully. In this paper, we present a framework for cognitive load application and describe a demonstration system. The framework imposes a load on a student who tries to understand an explanation. The important point toward the load application is to provide the student with an optimal load that does not go beyond his/her capacity for understanding. This requires controlling the students load by means of explanations. In order to implement such load control, it is necessary to estimate how much load the explanation imposes on his/her understanding process. The load estimate depends on his/her understanding capability since the same explanation imposes a different load according to the capability. Therefore a student model representing his/her capability is required. This paper shows how our system accomplishes a proper load application by generating explanations with the load estimate.

Web grammars and several graphs

This paper is concerned with the class of web grammars introduced by Pfaltz Rosenfeld and Montanari. In this paper, we show that context-sensitive web grammar cannot erase arcs, and monotone context-sensitive web grammar can erase arcs but cannot erase any vertices and they satisfy the condition |@a|@?|@b| in the rules @a@?@b. Then some hierarchical results hold, when grammars are normal and nonnormal. Normal grammars have rules that each vertex to be rewritten has exactly one image in the right member of the rule; nonnormal ones have rules that some vertices have two more images. Also, it is shown that there exists a complete grammar which generates some types of Eulerian graphs, line graphs and 3-connected graphs.

General formulation of formal grammars

Abstract By extracting the basic properties common to the formal grammars appeared in existing literatures, we develop a general formulation of formal grammars. We define a pseudo grammar and derive from it the well-known probabilistic, fuzzy grammars and so on. Moreover, several interesting grammars such as ⊔∗ grammars, ⊔ ⊓ grammars, ⊔ ⊓ grammars, composite B -fuzzy grammars, and mixed fuzzy grammars, which have never appeared in any other papers before, are derived.

N-fold fuzzy grammars

A new form of fuzzy grammar, which is called an n-fold fuzzy grammar, is defined and some of its properties are investigated. The n-fold fuzzy grammars are a generalization of fuzzy grammars defined by Lee and Zadeh, where the grade of application of the rule to be used next is conditioned by the n(⩾1) rules used before in a derivation. The n-fold fuzzy grammars whose rules are of context-free form can be shown to generate context-sensitive languages by setting a threshold appropriately. Fuzzy grammars by Lee and Zadeh with context-free rules, however, cannot generate context-sensitive languages. As to n-fold fuzzy grammars, we mainly focused our attention on n-fold fuzzy grammars with type 3 rules as a preliminary step.

Various kinds of automata with weights

By extracting the basic properties common to the automata appeared in existing literatures, we develop a general formulation of automata with ?weights?. We define a pseudoautomaton and derive from it the well-known deterministic automaton, nondeterministic automaton, probabilistic automaton, fuzzy automaton, and so on. Moreover, several interesting automata such as l-semigroup automaton, lattice automaton, dual lattice automaton, mixed boolean automaton, semiring automaton, ring automaton and field automaton which have never appeared in any other paper before are derived.

L-fuzzy grammars

Abstract An L -fuzzy grammar is defined by assigning the element of lattice to the rewriting rules of a formal grammar. According to the kind of lattice, say, distributive lattice, lattice-ordered group, and lattice-ordered monoid, two type of L -fuzzy grammars are defined. It is shown that some context-sensitive languages can be generated by type 3 ∗-L- fuzzy grammars with cut points. It is also shown that for type 2 L -fuzzy grammars, Chomsky and Greibach normal form can be constructed as an extension of corresponding notion in the theory of formal grammars.

Providing Problem Explanation for ITS

This paper describes a problem solving model and a problem explanation facility. Mastering the use of a solution method plays a crucial role in the progress of human problem solving capability. Our research aims at accomplishing an ITS which assists a student to master the use of a solution method. A student who can solve an example problem cannot always solve any exercise problems. Thus it becomes important to explain the equivalence between the two problems. In order to realize the explanation, we propose a problem solving model referred to as MIPS which provides a framework and vocabularies for describing the process of solution method selection. A problem solving module and a problem explanation module have been already implemented based on MIPS. The problem solving module is capable of solving several kinds of arithmetical word problems. Moreover, it describes the process of solution method selection. The problem explanation module derives the problem explanation from the description.

A Similarity Measure Between Patterns with Nonindependent Attributes

A generalized version of a set-theoretical measure for obtaining similarities between patterns with nonindependent attributes is presented. The dependence here is given by the pairwise correlation. Since the proposed measure needs no assumption of attribute independence, the resulting similarity values can reflect directly the relationships between the attributes.

Adaptive Postviewer for Constructive Learning in Hyperspace

Self-directed learning in hyperspace requires learners to monitor their navigation process involving knowledge construction, which they have carried out so far, since what and how they have learned becomes hazy as the navigation progresses. Although the reflective monitoring is an important activity in the self-directed learning, it is hard for them to keep it during navigating pages. The main issue addressed here is how to support the reflective monitoring. Our approach to this issue is to provide learners with the postviews of their knowledge construction adapted to their navigation process. Following the idea of adaptive postviewing, we have proposed an adaptive postviewer for self-directed learning with existing web-based resources. It generates page postviews and knowledge map, which display information suitable for their reflective monitoring to promote the constructive learning in hyperspace.