The Evaluation of Ambiguity Based on the Distance between Transitive Verbs and Objects in Japanese

A method exists for detecting ambiguous expressions in requirements specifications using a dictionary focused on transitive verbs and their objects. This dictionary is constructed by extracting transitive verbs and objects from the requirements specifications and classifying them for inclusion based on specific conditions. Sentences with ambiguous expressions can be detected by searching for sentences containing transitive verbs and objects found in the dictionary. The accuracy of this dictionary has been observed to improve when more requirements specifications are used as input data. However, the selection criteria for constructing the dictionary and filtering ambiguous sentences after extraction have not been thoroughly examined, indicating that the accuracy of ambiguous sentence extraction could be further improved.In this study, to further enhance the accuracy of this dictionary, we measured the distance between the detected transitive verbs and objects within sentences to determine whether the sentence is ambiguous. We conducted a t-test to compare the average distance between transitive verbs and objects in ambiguous and non-ambiguous sentences. The two-tailed test yielded a p-value of 0.0367 at a 5% significance level, indicating a significant difference in the distances between transitive verbs and objects. Therefore, we confirmed that the accuracy of the dictionary can be improved by weighting the words in the dictionary based on the distance between transitive verbs and objects.Detecting ambiguous expressions with high accuracy is expected to increase the efficiency of reviewing the contents of requirements specifications and reduce the difficulty of clarifying specifications. This will contribute to better scope management in project management. Consequently, the proposed approach is expected to prevent delays and cost overruns, contributing to more effective schedule and cost management.