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1994 | Buch

Concept Formation and Knowledge Revision

verfasst von: Stefan Wrobel

Verlag: Springer US

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A fundamental assumption of work in artificial intelligence and machine learning is that knowledge is expressed in a computer with the help of knowledge representations. Since the proper choice of such representations is a difficult task that fundamentally affects the capabilities of a system, the problem of automatic representation change is an important topic in current research. Concept Formation and Knowledge Revision focuses on representation change as a concept formation task, regarding concepts as the elementary representational vocabulary from which further statements are constructed.
Taking an interdisciplinary approach from psychological foundations to computer implementations, the book draws on existing psychological results about the nature of human concepts and concept formation to determine the scope of concept formation phenomena, and to identify potential components of computational concept formation models. The central idea of this work is that computational concept formation can usefully be understood as a process that is triggered in a demand-driven fashion by the representational needs of the learning system, and identify the knowledge revision activities of a system as a particular context for such a process.
The book presents a detailed analysis of the revision problem for first-order clausal theories, and develops a set of postulates that any such operation should satisfy. It shows how a minimum theory revision operator can be realized by using exception sets, and that this operator is indeed maximally general. The book then shows that concept formation can be triggered from within the knowledge revision process whenever the existing representation does not permit the plausible reformulation of an exception set, demonstrating the usefulness of the approach both theoretically and empirically within the learning knowledge acquisition system MOBAL.
In using a first-order representation, this book is part of the rapidly developing field of Inductive Logic Programming (ILP). By integrating the computational issues with psychological and fundamental discussions of concept formation phenomena, the book will be of interest to readers both theoretically and psychologically inclined.

From the foreword by Katharina Morik:

` The ideal to combine the three sources of artificial intelligence research has almost never been reached. Such a combined and integrated research requires the researcher to master different ways of thinking, different work styles, different sets of literature, and different research procedures. It requires capabilities in software engineering for the application part, in theoretical computer science for the theory part, and in psychology for the cognitive part. The most important capability for artificial intelligence is to keep the integrative view and to create a true original work that goes beyond the collection of pieces from different fields.
This book achieves such an integrative view of concept formation and knowledge revision by presenting the way from psychological investigations that indicate that concepts are theories and point at the important role of a demand for learning. to an implemented system which supports users in their tasks when working with a knowledge base and its theoretical foundation. '

Inhaltsverzeichnis

Frontmatter
1. Introduction
Abstract
Ever since the advent of computers, people have been intrigued by the possibility of making computers exhibit behavior similar to the general intelligent capabilities of humans. Since the early fifties of this century, this goal is being addressed in the subdiscipline of computer science that has come to be known under the name of Artificial Intelligence (AI) [Charniak and McDermott, 1985; Winston, 1992]. We can define the goal of this discipline in a general fashion as the construction of computer models of behavior that is regarded as intelligent in humans. Over the course of AI’s history, the kinds of behavior that have been studied have varied, and there is no universally accepted position on what form the computer model is to take, and whether it is to be regarded as an embodiment of intelligence or, as the author believes, merely an operational description of intelligence (see [Morik, 1992, ch. 1]).
Stefan Wrobel
2. The Psychology of Concepts and Concept Formation
Abstract
In the preceding chapter, we saw that the design of a representation system requires choices on two different levels. First, there is the level of representation formalism, i.e., the choice of syntax and semantics for the representation. Then, there is the equally important choice of a representation language, i.e., the vocabulary to be made available in the chosen formalism. We also saw that this vocabulary is to be looked at not as a set of syntactical terms, but as a system of concepts.
Stefan Wrobel
3. Concept Representation in a Paraconsistent Logic with Higher-Order Elements
Abstract
The discussion of psychological data on human concept formation in the preceding chapter (chapter 2) has enabled us to arrive at a number of minimal requirements that a knowledge representation should meet if it is to serve as the basis of a computational model of concepts and concept formation. As a central conclusion, we observed that a propositional formalism is insufficient to represent people’s knowledge about concepts, their features, and their relationships to other concepts.
Stefan Wrobel
4. Knowledge Revision as a Concept Formation Context
Abstract
After discussing the technical aspects of what concepts are and how they are represented in the preceding chapter, let us now return to the issue of how concepts are formed. In chapter 2, we had concluded that one of the most important sources of constraints on concept formation is its embedding in a particular context. Based on those psychological arguments, our choice was to examine a demand-driven concept formation approach, i.e., an approach that forms concepts only when there is a specific need for a new concept arising out of the problem solving activities of the system.
Stefan Wrobel
5. Demand-Driven Concept Formation
Abstract
With the discussion of KRT knowledge revision in the preceding chapter, we have finally assembled the three pillars upon which our model of computational concept formation is to be built:
  • In chapter 2, we have discussed a number of psychological results as hints to the requirements for concept representation, and the possible mechanisms for concept formation.
  • In chapter 3, we developed a logical representation language that meets most of the psychological requirements on concept representation, and showed that it has a well-defined semantics and is tractable.
  • In chapter 4 finally, we discussed MOBAL’s knowledge revision activities, which are to provide the context for concept formation.
Stefan Wrobel
6. Embeddedness
Abstract
In the preceding chapters, we have discussed the psychological foundations and technical realization of a model of demand-driven concept formation that exploits the problem-solving context of the reasoner to help it decide which new concepts to introduce into the representation. The method constructs new concepts out of concepts (or predicates) already existing in the representation by combining them into rules that express sufficient or necessary conditions on concept membership. This means that the approach must assume the elementary building blocks of concepts as given, and seems unable to account for the origin of truly new features or concepts that are not combinations of existing ones.
Stefan Wrobel
7. Conclusions
Abstract
At the end of this book, we want to conclude with an assessment of areas where we hope this book will make a contribution, a description of problems that are still open, and a discussion of possible future work.
Stefan Wrobel
A. Mobal Software Info Page
Abstract
MOBAL [Morik et al., 1993] (see also section 1.6) is a sophisticated system for developing, validating, and maintaining operational models of application domains. It integrates a manual knowledge acquisition and inspection environment, a powerful inference engine, machine learning methods for automated knowledge acquisition, and a knowledge revision tool.
Stefan Wrobel
B. Glossary of Symbols
Abstract
This glossary lists the important symbols and abbreviations that are used in the text, in the order of first occurrence. The first column of the table contains the symbol or abbreviation, the second provides a short reminder of its meaning, and the third lists the page or pages where the symbol is defined or first mentioned.
Stefan Wrobel
Backmatter
Metadaten
Titel
Concept Formation and Knowledge Revision
verfasst von
Stefan Wrobel
Copyright-Jahr
1994
Verlag
Springer US
Electronic ISBN
978-1-4757-2317-5
Print ISBN
978-1-4419-5146-5
DOI
https://doi.org/10.1007/978-1-4757-2317-5