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WordNet::Similarity::hUser)Contributed Perl DocumenWordNet::Similarity::hso(3)

       WordNet::Similarity::hso	- Perl module for computing semantic
       relatedness of word senses using	the method described by	Hirst and
       St-Onge (1998).

	 use WordNet::Similarity::hso;

	 use WordNet::QueryData;

	 my $wn	= WordNet::QueryData->new();

	 my $object = WordNet::Similarity::hso->new($wn);

	 my $value = $object->getRelatedness("car#n#1",	"bus#n#2");

	 ($error, $errorString)	= $object->getError();

	 die "$errorString\n" if($error);

	 print "car (sense 1) <-> bus (sense 2)	= $value\n";

       This module computes the	semantic relatedness of	word senses according
       to the method described by Hirst	and St-Onge (1998). In their paper
       they describe a method to identify 'lexical chains' in text. They
       measure the semantic relatedness	of words in text to identify the links
       of the lexical chains. This measure of relatedness has been implemented
       in this module.

	   This	method is internally called to determine the parts of speech
	   this	measure	is capable of dealing with.

	   Parameters: none.

	   Returns: none.

       $hso->getRelatedness ($synset1, $synset2)
	   Computes the	relatedness of two word	senses using the method	of
	   Hirst & St-Onge.

	   Parameters: two word	senses in "word#pos#sense" format.

	   Returns: Unless a problem occurs, the return	value is the
	   relatedness score, which is greater-than or equal-to	0 and less-
	   than	or equal-to 16.	 If an error occurs, then the error level is
	   set to non-zero and an error	string is created (see the description
	   of getError()).

       The semantic relatedness	modules	in this	distribution are built as
       classes that define the following methods:


       See the WordNet::Similarity(3) documentation for	details	of these

       Typical Usage Examples

       To create an object of the hso measure, we would	have the following
       lines of	code in	the Perl program.

	  use WordNet::Similarity::hso;
	  $measure = WordNet::Similarity::hso->new($wn,	'/home/sid/hso.conf');

       The reference of	the initialized	object is stored in the	scalar
       variable	'$measure'. '$wn' contains a WordNet::QueryData	object that
       should have been	created	earlier	in the program.	The second parameter
       to the 'new' method is the path of the configuration file for the hso
       measure.	If the 'new' method is unable to create	the object, '$measure'
       would be	undefined. This, as well as any	other error/warning may	be

	  die "Unable to create	object.\n" if(!defined $measure);
	  ($err, $errString) = $measure->getError();
	  die $errString."\n" if($err);

       To find the semantic relatedness	of the first sense of the noun 'car'
       and the second sense of the noun	'bus' using the	measure, we would
       write the following piece of code:

	  $relatedness = $measure->getRelatedness('car#n#1', 'bus#n#2');

       To get traces for the above computation:

	  print	$measure->getTraceString();

       However,	traces must be enabled using configuration files. By default
       traces are turned off.

       The behavior of the measures of semantic	relatedness can	be controlled
       by using	configuration files. These configuration files specify how
       certain parameters are initialized within the object. A configuration
       file may	be specififed as a parameter during the	creation of an object
       using the new method. The configuration files must follow a fixed

       Every configuration file	starts with the	name of	the module ON THE
       FIRST LINE of the file. For example, a configuration file for the hso
       module will have	on the first line 'WordNet::Similarity::hso'. This is
       followed	by the various parameters, each	on a new line and having the
       form 'name::value'. The 'value' of a parameter is optional (in case of
       boolean parameters). In case 'value' is omitted,	we would have just
       'name::'	on that	line. Comments are supported in	the configuration
       file. Anything following	a '#' is ignored till the end of the line.

       The module parses the configuration file	and recognizes the following

	   The value of	this parameter specifies the level of tracing that
	   should be employed for generating the traces. This value is an
	   integer equal to 0, 1, or 2.	If the value is	omitted, then the
	   default value, 0, is	used. A	value of 0 switches tracing off. A
	   value of 1 or 2 switches tracing on.	A trace	of level 1 means the
	   synsets are represented as word#pos#sense strings, while for	level
	   2, the synsets are represented as word#pos#offset strings.

	   The value of	this parameter specifies whether or not	caching	of the
	   relatedness values should be	performed.  This value is an integer
	   equal to  0 or 1.  If the value is omitted, then the	default	value,
	   1, is used. A value of 0 switches caching 'off', and	a value	of 1
	   switches caching 'on'.

	   The value of	this parameter indicates the size of the cache,	used
	   for storing the computed relatedness	value. The specified value
	   must	be a non-negative integer.  If the value is omitted, then the
	   default value, 5,000, is used. Setting maxCacheSize to zero has the
	   same	effect as setting cache	to zero, but setting cache to zero is
	   likely to be	more efficient.	 Caching and tracing at	the same time
	   can result in excessive memory usage	because	the trace strings are
	   also	cached.	 If you	intend to perform a large number of
	   relatedness queries,	then you might want to turn tracing off.

       perl(1),	WordNet::Similarity(3),	WordNet::QueryData(3)

	Ted Pedersen, University of Minnesota Duluth
	tpederse at

	Siddharth Patwardhan, University of Utah, Salt Lake City
	sidd at


       Copyright (c) 2005, Ted Pedersen	and Siddharth Patwardhan

       This program is free software; you can redistribute it and/or modify it
       under the terms of the GNU General Public License as published by the
       Free Software Foundation; either	version	2 of the License, or (at your
       option) any later version.

       This program is distributed in the hope that it will be useful, but
       WITHOUT ANY WARRANTY; without even the implied warranty of
       General Public License for more details.

       You should have received	a copy of the GNU General Public License along
       with this program; if not, write	to

	   The Free Software Foundation, Inc.,
	   59 Temple Place - Suite 330,
	   Boston, MA  02111-1307, USA.

       Note: a copy of the GNU General Public License is available on the web
       at <>	and is included	in this
       distribution as GPL.txt.

perl v5.24.1			  2008-03-27	   WordNet::Similarity::hso(3)


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