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How do I decide whom to follow on Twitter ?. IARank: Ranking Users on Twitter in Near Real-time, Based on their Information Amplification Potential. Motivation. Follow the right users in order to catch up the breaking news. (Twitter showed to be a very good news media social network)
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How do I decide whom to follow on Twitter ? IARank: Ranking Users on Twitter in Near Real-time, Based on their Information Amplification Potential
Motivation • Follow the right users in order to catch up the breaking news. (Twitter showed to be a very good news media social network) • Cost-effective users. (chain reaction of information spread by word-of-mouth) • PageRank-like algorithms have been used to rank users in Twitter in the past, however their convergence time is non-trivial. • Therefore, it is not possible to rank users in large-scale events in near real-time since the ranks need to be recomputed after every tweet is received.
Data Set Summary Data Set used to test and compare the Ranking systems.
Influence • Defining Influence. How much excitation a user causes in the network by receiving attention from other users. • Retweets, Replies and Mentions. Retweets, replies and mentions are mechanisms of interaction between users in Twitter in which they can show interest to tweets or usernames. More interactions a user receives, more attention they have achieved. • Influence accumulated over time versus Instant Influence.
Models of Influence • Cumulative Influence Model: Summation of interactions, weighed by an Information amplification factor. • Instantaneous Influence Model: User k receives the accumulated influence from user j, plus his previous value of influence decayed by an α constant.
Information Amplification • Amplification of Information as a measure of influence is the capacity of a user to amplify the reach of a post shared by another user. • Features which can measure Information Amplification: • Buzz factor: • Event activity. how many times a user actively participated in an event • Attention acquired. how much attention a user received, directly related to the content of the their posts • Structure Advantage factor: • Social connectivity. Popularity, how many people are connected to the user and have direct and instant access to their tweets.
Information Amplification • Each weighed link in the cumulative influence model is substituted by the factors which measure the information amplification of a user. • Resulting in the fully defined model of cumulative Influence (IARank):
Performance Evaluation: User Study for LFW event • Poll 1: • Do you know this user? • It this user relevant to the event? • Would you follow this user? • Poll 2: Reference Rank: Top 20 from IARank and PageRank
Performance Evaluation: Comparison Measures • Scaling levels of comparison: • Sets: content comparison • Position: accounts for the difference between the users positions within the sets • Ranking progression, or accordance between ranks: how similar is a sequence of ranked usernames between two ranks. • Respectively, each level requires an appropriate mathematical tool: Precision, Error and Pearson’s Correlation.
Conclusion • This work showed that PageRank is not fast enough rank users in large-scale events such as London Fashion Week, Ipad 3 and London Olympics. • IARank, a simpler, faster and accurate ranking system was designed based on the concept of information amplification, which takes as influential those users who are generating buzz in the network, or have a potential to reach a high audience. • The ranking scheme is capable to accurately rank the most influential users in near real-time for large-scale events. • IARank was evaluated with a user study, which showed that it is marginally better than PageRank in finding relevant usernames. However, PageRank have a slightly better correlation and smaller error in comparison with the rank manually generated by the user study participants, inferring that there is a noticeable trade-off between having a small processing time and the accuracy of the recommended list. • Lastly, our user study also revealed that users have different personal opinions on the kinds of sources or usernames that would be useful to them. Therefore, incorporating personal preferences into a ranking scheme is likely to be a promising direction for further improving the performance of the IARank.