Word-Oriented Approximate String Matching Using Occurrence Heuristic Tables: A Heuristic for Searching Arabic Text

In this article, a word-oriented approximate string matching approach for searching Arabic text is presented. The distance between a pair of words is determined on the basis of aligning the two words by using occurrence heuristic tables. Two words are considered related if they have the same morphological or lexical basis. The heuristic reports an approximate match if common letters agree in order and noncommon letters represent valid affixes. The heuristic was tested by using four different alignment strategies: forward, backward, combined forward–backward, and combined backward– forward. Using the error rate and missing rate as performance indicators, the approach was successful in providing more than 80% correct matches. Within the conditions of the experiments performed, the results indicated that the combined forward–backward strategy seemed to exhibit the best performance. Most of the errors were caused by multiple-letter occurrences and by the presence of weak letters in cases in which the shared core consisted of one or two letters.