Stemming Indonesian - Techniques 2

Stemming Indonesian - Techniques 2

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• Saturday, October 5, 2013

Pre x Disallowed su xes
be- -i
di- -an
ke- -i, -kan
me- -an
se- -i,-kan
te- -an
Table 1: Disallowed pre x and su x combinations.
The only exception is that the root word \tahu" is
permitted with the pre x \ke-" and the su x \-i".
The square brackets indicate that an a x is optional.
The previous de nition forms the basis of the rules
used in the approach. However, there are exceptions
and limitations that are incorporated in the rules:
1. Not all combinations are possible. For example,
after a word is pre xed with \di-", the word is
not allowed to be su xed with \-an". A complete list is shown in Table 1
2. The same a x cannot be repeatedly applied. For
example, after a word is pre xed with \te-" or
one of its variations, it is not possible to repeat
the pre x \te-" or any of those variations
3. If a word has one or two characters, then stemming is not attempted.
4. Adding a pre x may change the root word or
a previously-applied pre x; we discuss thi… Stemming Indonesian - Techniques 2

Stemming Indonesian - Stemming Techniques 1

Stemming Indonesian - Stemming Techniques 1

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2 Stemming Techniques
In this section, we describe the ve schemes we have
evaluated for Indonesian stemming. In particular, we
detail the approach of Nazief and Adriani, which performs the best in our evaluation of all approaches in
Section 4. We propose extensions to this approach in
Section 5.

2.1 Nazief and Adriani's Algorithm
The stemming scheme of Nazief and Adriani is described in an unpublished technical report from the
University of Indonesia (1996). In this section, we describe the steps of the algorithm, and illustrate each
with examples; however, for compactness, we omit
the detail of selected rule tables. We refer to this
approach as nazief.
The algorithm is based on comprehensive morphological rules that group together and encapsulate allowed and disallowed a xes, including pre xes, suf-
xes, in xes (insertions) and con xes (combination
of pre xes and su xes). The algorithm also supports
recoding, an approach to restore an initial letter that
was removed from a root… Stemming Indonesian - Stemming Techniques 1

Stemming Indonesian - Introduction

Stemming Indonesian - Introduction

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1 Introduction
Stemming is a core natural language processing
technique for e cient and e ective Information Retrieval (Frakes 1992), and one that is widely accepted
by users. It is used to transform word variants to their
common root word by applying | in most cases |
morphological rules. For example, in text search, it
should permit a user searching using the query term
\stemming" to nd documents that contain the terms
\stemmer" and \stems" because all share the common root word \stem". It also has applications in
machine translation (Bakar & Rahman 2003), document summarisation (Oras an, Pekar & Hasler 2004),
and text classi cation (Gaustad & Bouma 2002).
For the English language, stemming is wellunderstood, with techniques such as those of
Lovin (1968) and Porter (1980) in widespread use.
However, stemming for other languages is less wellknown: while there are several approaches available
for languages such as French (Savoy 1993), Spanish (Xu &… Stemming Indonesian - Introduction

Stemming Indonesian - Abstract

Stemming Indonesian - Abstract

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Stemming Indonesian
Jelita Asian Hugh E. Williams S.M.M. Tahaghoghi
School of Computer Science and Information Technology
RMIT University, GPO Box 2476V, Melbourne 3001, Australia.
fjelita,hugh,saiedg@cs.rmit.edu.au

Abstract
Stemming words to (usually) remove su xes has applications in text search, machine translation, document summarisation, and text classi cation. For example, English stemming reduces the words \computer", \computing", \computation", and \computability" to their common morphological root,
\comput-". In text search, this permits a search for
\computers" to nd documents containing all words
with the stem \comput-". In the Indonesian language, stemming is of crucial importance: words
have pre xes, su xes, in xes, and con xes that make
matching related words di cult. In this paper, we
investigate the performance of ve Indonesian stemming algorithms through a user study. Our results
show that, with the availability of a reasonable dic… Stemming Indonesian - Abstract