Development and Enhancement of a Stemmer for the Greek Language
Georgios Ntais, Spyridon Saroukos, Eleni Berki, Hercules Dalianis · 2016
Although there are three stemmers published for the Greek language, only the one presented in this paper and called Ntais' stemmer is freely open and available, together with its enhancements and extensions according to Saroukos' algorithm. The primary algorithm (Ntais' algorithm) uses only capital letters and works with better performance than other past stemming algorithms for the Greek language, giving 92.1 percent correct results. Further extensions of the proposed stemming system (e.g. from capital to small letters) and more evaluation methods are presented according to a new and improved algorithm, Saroukos' algorithm. Stemmer performance metrics are further used for evaluating the existing stemming system and algorithm and show how its accuracy and completeness are enhanced. The improvements were possible by providing an alternative implementation in the programming language PHP, which offers more syntactical rules and exceptions. The two versions of the stemming algorithm are tested and compared.