Tweets Monitored to detect a target event of social sensor in location estimation

Twitter, a popular microblogging service, has received much attention recently. This online social network is used by millions of people around the world to remain socially connected to their friends, family members, and coworkers through their computers and mobile phones. Twitter asks one question, “What’s happening?” Answers must be fewer than 140 characters. A status update message, called a tweet, is often used as a message to friends and colleagues. A user can follow other users; that user’s followers can read her tweets on a regular basis. A user who is being followed by another user need not necessarily reciprocate by following them back, which renders the links of the network as directed.1 Currently, 190 million users use Twitter per month, generating 65 million tweets per day.2 Many researchers have published their studies of Twitter to date, especially during the past year. Most studies can be classified into one of three groups: first, some researchers have sought to analyze the network structure of Twitter. Twitter is categorized as a microblogging service. Microblogging is a form of blogging that enables users to send brief text updates or micromedia such as photographs or audio clips. Microblogging services other than Twitter include Tumblr, Plurk, Jaiku, identi.ca, and others.3 Our study, which is based on the real-time nature of one social networking service, is applicable to other microblogging services, but we specifically examine Twitter in this study because of its popularity and data volume. It is common among microblogging services is their real-time nature. Although blog users typically update their blogs once every several days, Twitter users write tweets several times in a single day. Users can know how other users are doing and often what they are thinking about now, users repeatedly return to the site and check to see what other people are doing. The real-time nature of Twitter that is designed to ascertain whether we can extract valid information from it.