N-rule
From UNL Wiki
(Difference between revisions)
(→Roles of Normalization Rules) |
(→Type of Normalization Rules) |
||
| Line 7: | Line 7: | ||
== Type of Normalization Rules == | == Type of Normalization Rules == | ||
| − | Normalization rules are used | + | Normalization rules are string replacement rules. They are used to replace existing strings by new strings. |
{|cellpadding="5" border="1" align="center" | {|cellpadding="5" border="1" align="center" | ||
| Line 21: | Line 21: | ||
|} | |} | ||
<div align="center">Where %x and %y are nodes.</div> | <div align="center">Where %x and %y are nodes.</div> | ||
| − | |||
== Roles of Normalization Rules == | == Roles of Normalization Rules == | ||
Revision as of 20:02, 31 May 2013
Normalization rules are used to prepare the natural language input for automatic processing. They constitute the preprocessing module that applies over the input as a string and runs prior to the tokenization. The set of n-rules forms the Normalization Grammar, or N-Grammar.
Contents |
Syntax
Normalization Rules follow the very general formalism
α:=β;
where the left side α is a condition statement, and the right side β is an action to be performed over α.
Type of Normalization Rules
Normalization rules are string replacement rules. They are used to replace existing strings by new strings.
| ACTION | RULE | DESCRIPTION |
|---|---|---|
| REPLACE | (%x):=(%y); | All the instances of the node %x will be replaced by the node %y |
Where %x and %y are nodes.
Roles of Normalization Rules
Normalization roles have two roles:
- to normalize the input text (to replace abbreviations by their extend forms, to extend contractions, etc.)
- to segment the natural language text into sentences (i.e., to create the tags <SHEAD> (beginning of a sentence), <STAIL> (end of a sentence), <CHEAD> (beginning of a scope) and <CTAIL> (end of a scope) inside the input text). These tags are used as sentence and clause boundaries, and define the units of processing of the Transformation and Disambiguation grammars.
Examples of Normalization rules
- Segmentation
- ("/.*\./",%x):=(%x)(+STAIL,%y); (creates an STAIL node after any sequence of characters followed by "." (/.*\./);
- ("/\(/",%x):=(+CHEAD,%y)(%x); (creates an CHEAD node before the opening of a parentheses (/\(/);
- Normalization
- ("an "):=("a "); ("an apple" > "a apple")
- ("don't"):=("do not"); ("I don't see" > "I do not see")
