A Combined Method for Usage of NLP Libraries Towards Analyzing Software Documents

Natural Language Processing (NLP) library is widely used while analyzing software documents. The numerous toolkits result in a problem on NLP library selection. The selection of NLP library in current work commonly misses some objective reasons, which may pose threats to validity. And it is also not clear that whether the existing guideline on selection still works for the latest versions. In this work, we propose a solution for NLP library selection when the effectiveness is unknown. We use the NLP libraries together in a combined method. Our combined method can utilize the strengths of different NLP libraries to obtain accurate results. The combination is conducted through two steps, i.e., document-level selection of NLP library and sentence-level overwriting. In document-level selection of primary library, the results are obtained from the library that has the highest overall accuracy. Through sentence-level overwriting, the possible fine-gained improvements from other libraries are extracted to overwrite the outputs of primary library. We evaluate the combined method with 4 widely used NLP libraries and 200 documents from 3 different sources. The results show that the combined method can generally outperform all the studied NLP libraries in terms of accuracy. The finding means that our combined method can be used instead of individual NLP library for more effective results.