Browsing by Author "Mekonnen, Wakshum"

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    Development of a Stemming Algorithm for Afaan Oromoo Text
    (Addis Ababa University, 2000-06) Mekonnen, Wakshum; Alemayehu, Nega (PhD)
    This paper reports the design and development of a stemming algorithm for Afaan 01"011100 language. Reviews of Afaan Oromoo morphology, stemming algorithms, and other relevant materials were made. In Afaan Oromoo, inflectional and derivational affixations are the major word formation processes. The initial design of the stemming algorithm was based on free-context conflation procedures following the longest-match suffix removal approach. An accuracy rate of 71 % was obtained from this initial attempt. The improved algorithm incorporated suffix, context-sensitive, and recording reles in the procedures. Before stemming, functional and frequently occurring words, which were compiled as stop list, are excluded from the input term(s) to increase the efficiency of the stemmer. Procedures for prefix removal and for conflation of words formed by reduplication of first syllable are also components of the modified algorithm . Using the modified stemmer an accuracy rate of92% was gained from the test based on a sample of 1061 words. The percentage of errors recorded as understenuning and over stemming were reduced to 4.58% and 2.5% respectively from 10.5% and 17.5% for the first version. A substantial decrease in size of sample text is achieved from this stemmer. The morphological complexity of the language is the main sources of errors for the resulting inaccuracies of the stemming algorithm. For further improvement of the stemmer therefore, detailed study ofaan oromoo morphology is helpful. The result of this study in general shows the possibility of employing a stemming algorithm for conflating Afaan orpmpp words.