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.
This is a preview of subscription content, log in via an institution to check access.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Preview
Unable to display preview. Download preview PDF.
References
Here, we define the revision operations with respect to single fact revisions; in section 4.5.3, we generalize them to perform multiple revisions at the same time.
is to be read as “exclusive or”. This third operation is necessary because MOBAL permits additions which are inconsistent at first and are resolved later on, see below.
This is a simplified version of the Levi identity known from theory change work ([Levi, 1977] foll. [Nebel, 1989]).
Two less important supplementary postulates that deal with the properties of conjunction under removal are also sometimes used.
The term besserwisser is due to [Gärdenfors, 1988].
Clearly, this measure is not without problems, as the number of applications of a rule directly depends on what other rules are in the theory. Thus a rule that appears very strong before revision may end up very weak if another rule that produced the former rule’s antecedents is removed.
Thanks to J.U. Kietz for pointing this out.
This also implies that ø will always keep the side of a contradiction that is supported by an input fact, which corresponds well with our intentions.
Without assuming maximal predicate arities.
This table shows only the reformulation operators that use existing concepts. In chapter 5, we define additional operators that use CLT to introduce new concepts for reformulation.
In the following, we omit the variable list of the support set.
As pointed out in [Emde, 1991], using supports sets instead of premises also means that rules which have been revised are easy to find in the knowledge base if this should become necessary.
In chapter 5, this table will be extended to include the concept formation operators.
If desired, such rules can also be learned by letting RDT or some other learning algorithm analyze the manually assigned access rights.
It can be shown that different programming languages change the size of this quantity only by an additive factor.
[Srinivasan et al., 1994] point out that equivalently this evaluation could be incorporated into the CWS specialization directly.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 1994 Springer Science+Business Media Dordrecht
About this chapter
Cite this chapter
Wrobel, S. (1994). Knowledge Revision as a Concept Formation Context. In: Concept Formation and Knowledge Revision. Springer, Boston, MA. https://doi.org/10.1007/978-1-4757-2317-5_4
Download citation
DOI: https://doi.org/10.1007/978-1-4757-2317-5_4
Publisher Name: Springer, Boston, MA
Print ISBN: 978-1-4419-5146-5
Online ISBN: 978-1-4757-2317-5
eBook Packages: Springer Book Archive