# Expert Recommendation for Answering Questions on Social Media
## 1 Introduction  
The use of social media for generating and sharing thoughts or opinions among users has increased [1, 2, 3, 4] with advancements in network technology and mobile devices. Social media are communication media that facilitate interactions or develop interdependent relationships between individuals and groups [5, 6]. Social Networking Service (SNS) is a typical social media service used for communication and information sharing between users based on a human network of users [7, 8, 9, 10]. Recently, SNS has been used to create, reprocess, and propagate new information, having evolved from a method of simple information sharing.  
Because a large amount of information is reproduced and shared exponentially through SNS, users want to see only the information they demanded [11, 12, 13]. Furthermore, because unverified information is spread by non-experts, users must determine the level of trustworthiness of the information circulating on social media. In such an environment, social media users wish to find experts who can provide the desired information or answers to their queries [14, 15, 16]. Recently, services have been developed to answer questions by social media users [17, 18, 19]. There are online Question and Answer (Q&A) services such as Yahoo Answers, Naver Knowledge iN, and Baidu Knows, where users can ask questions and answer questions freely online. Recently, social Q&A services that combine social media and online Q&A services have been developed. Quora, for example, is an online social service that enables anyone to ask questions and comment on the answers that have been submitted by other users. On social media, users can get answers to questions throughQ&A services by registering feature problems and questions online. One problem with these Q&A services is that there may be inaccurate answers because many unspecified users can answer questions, and there may be no answers to specific questions. Further, since any unreliable user may answer a question, it may be difficult to obtain a high-quality answer. To solve these problems, it is necessary to identify and recommend experts who can answer the user's questions appropriately [20; 21; 22].  
Studies have been performed on expert recommendation services [23; 24] that recommend users who provide the requested information or provide a high-quality answer to a given question. Existing expert recommendation methods include recommendation methods based on direct input profiles of social media users and recommendation methods based on the analysis of user activities. The user profile method determines the similarity of user profiles with the question content and recommends a user who possesses the highest similarity. Because it simply compares a question and user profiles, the cost is low, but if the user profiles have not been updated or wrong information has been input with malicious intent, the precision of expert recommendations becomes low, which is a drawback [25; 26; 2  
in detail the characteristics and process of the proposed expert recommendation method. Section 4 proves the superiority of the proposed method through comparative performance evaluations between it and the existing expert recommendation methods. Finally, Section 5 provides the conclusions of this study and the directions for future studies.