I. Introduction
The keyword extraction is referred to the process of extracting important words which reflect essentially the content from a text, automatically. Even if the indexing is the process of extracting words from a text is similar as the task, the two tasks should be distinguished from each other. In this research, the keyword extraction is viewed into a binary classification where each word is classified into keyword or non-keyword, and the modified KNN version is proposed as the approach. A text is indexed into a list of words, they are classified into one of the two categories, and the words which are classified into keyword are extracted as the output. In this section, we briefly describe the motivation, the idea, and the validation of this research.