2,804 research outputs found
PROLOG META-INTERPRETERS FOR RULE-BASED INFERENCE UNDER UNCERTAINTY
Uncertain facts and inexact rules can be represented and
processed in standard Prolog through meta-interpretation. This
requires the specification of appropriate parsers and belief
calculi. We present a meta-interpreter that takes a rule-based
belief calculus as an external variable. The certainty-factors
calculus and a heuristic Bayesian belief-update model are then
implemented as stand-alone Prolog predicates. These, in turn,
are bound to the meta-interpreter environment through second-order
programming. The resulting system is a powerful
experimental tool which enables inquiry into the impact of
various designs of belief calculi on the external validity of
expert systems. The paper also demonstrates the (well-known)
role of Prolog meta-interpreters in building expert system
shells.Information Systems Working Papers Serie
META-INTERPRETERS FOR RULE-BASED REASONING UNDER UNCERTAINTY
One of the key challenges in designing expert systems is a credible representation
of uncertainty and partial belief. During the past decade, a number of
rule-based belief languages were proposed and implemented in applied systems.
Due to their quasi-probabilistic nature, the external validity of these
languages is an open question. This paper discusses the theory of belief revision
in expert systems through a canonical belief calculus model which is
invariant across different languages. A meta-interpreter for non-categorical
reasoning is then presented. The purposes of this logic model is twofold:
first, it provides a clear and concise conceptualization of belief representation
and propagation in rule-based systems. Second, it serves as a working
shell which can be instantiated with different belief calculi. This enables
experiments to investigate the net impact of alternative belief languages on
the external validity of a fixed expert system.Information Systems Working Papers Serie
Acquiring Word-Meaning Mappings for Natural Language Interfaces
This paper focuses on a system, WOLFIE (WOrd Learning From Interpreted
Examples), that acquires a semantic lexicon from a corpus of sentences paired
with semantic representations. The lexicon learned consists of phrases paired
with meaning representations. WOLFIE is part of an integrated system that
learns to transform sentences into representations such as logical database
queries. Experimental results are presented demonstrating WOLFIE's ability to
learn useful lexicons for a database interface in four different natural
languages. The usefulness of the lexicons learned by WOLFIE are compared to
those acquired by a similar system, with results favorable to WOLFIE. A second
set of experiments demonstrates WOLFIE's ability to scale to larger and more
difficult, albeit artificially generated, corpora. In natural language
acquisition, it is difficult to gather the annotated data needed for supervised
learning; however, unannotated data is fairly plentiful. Active learning
methods attempt to select for annotation and training only the most informative
examples, and therefore are potentially very useful in natural language
applications. However, most results to date for active learning have only
considered standard classification tasks. To reduce annotation effort while
maintaining accuracy, we apply active learning to semantic lexicons. We show
that active learning can significantly reduce the number of annotated examples
required to achieve a given level of performance
An overview of decision table literature 1982-1995.
This report gives an overview of the literature on decision tables over the past 15 years. As much as possible, for each reference, an author supplied abstract, a number of keywords and a classification are provided. In some cases own comments are added. The purpose of these comments is to show where, how and why decision tables are used. The literature is classified according to application area, theoretical versus practical character, year of publication, country or origin (not necessarily country of publication) and the language of the document. After a description of the scope of the interview, classification results and the classification by topic are presented. The main body of the paper is the ordered list of publications with abstract, classification and comments.
HUDDL for description and archive of hydrographic binary data
Many of the attempts to introduce a universal hydrographic binary data format have failed or have been only partially successful. In essence, this is because such formats either have to simplify the data to such an extent that they only support the lowest common subset of all the formats covered, or they attempt to be a superset of all formats and quickly become cumbersome. Neither choice works well in practice. This paper presents a different approach: a standardized description of (past, present, and future) data formats using the Hydrographic Universal Data Description Language (HUDDL), a descriptive language implemented using the Extensible Markup Language (XML). That is, XML is used to provide a structural and physical description of a data format, rather than the content of a particular file. Done correctly, this opens the possibility of automatically generating both multi-language data parsers and documentation for format specification based on their HUDDL descriptions, as well as providing easy version control of them. This solution also provides a powerful approach for archiving a structural description of data along with the data, so that binary data will be easy to access in the future. Intending to provide a relatively low-effort solution to index the wide range of existing formats, we suggest the creation of a catalogue of format descriptions, each of them capturing the logical and physical specifications for a given data format (with its subsequent upgrades). A C/C++ parser code generator is used as an example prototype of one of the possible advantages of the adoption of such a hydrographic data format catalogue
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