I. Introduction
In the era of the fourth industrial revolution, people are changing the way of communicating or exchanging information with the advance of Internet of Things (IoT), more specifically, smart devices (e.g., smart phones and sensors). This supports people to share every thing online; therefore, data is increasing its volume, velocity, and variety [1] in these years. There are various studies in computer science that aim to cope with extracting information from social data. One of the topics that many researchers feel interested in is discovering events [2], [3].