Page 232 - DCAP310_INTRODUCTION_TO_ARTIFICIAL_INTELLIGENCE_AND_EXPERT_SYSTEMS

Introduction to Artificial Intelligence & Expert Systems

Notes

Source: http://www.cs.ox.ac.uk/files/219/parsing.pdf

Notice that the ?ltering done by Predict eliminates several possible items based on the S -> NP
VP rule at the point where the NP '?sh' is the current constituent (items 7 and 9), because S is not
a left corner of VP, which is the current MotherCatSought. Items marked * lead to parsing paths
that do not go anywhere: these too could be ruled out by doing a left corner check when Shifting:
if the category of the item shifted is not a left corner of the ?rst item in DaughtersSought, then no
parse will result.

!
Caution Each tagger has its meaning and importance.

Task Read parts of speech (POS) tagger and their meaning.

Self Assessment

State whether the following statements are true or false:
7. Parsing algorithms are usually designed for classes of grammar rather than tailored
towards individual grammars.
8. There is only one dimension on which is useful to characterise the behaviour of parsing
algorithms.
9. A successful parse is represented by an item with no more input and a single S rooted tree
on the list.

12.4 Semantic Analysis and Representation Structures

Computers are very fast and powerful machines, however, they process texts written by humans
in an entirely mindless way, treating them merely as sequences of meaningless symbols. The
main goal of language analysis is to obtain a suitable representation of text structure and thus
make it possible to process texts based on their content. This is necessary in various applications,
such as spell- and grammar-checkers, intelligent search engines, text summarization, or dialogue
systems.
Natural language text can be analyzed on various levels, depending on the actual application
setting. With regard to automatic processing of language data, the following analysis levels can
be distinguished: Morphological analysis gives a basic insight into natural language by studying
how to distinguish and generate grammatical forms of words arising through inflection

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