Abu Nowshed CHY †a) , Md Zia ULLAH †b) , Nonmembers, and Masaki AONO †c) , Member
SUMMARYMicroblog, especially twitter, has become an integral part of our daily life for searching latest news and events information. Due to the short length characteristics of tweets and frequent use of unconventional abbreviations, content-relevance based search cannot satisfy user's information need. Recent research has shown that considering temporal and contextual aspects in this regard has improved the retrieval performance significantly. In this paper, we focus on microblog retrieval, emphasizing the alleviation of the vocabulary mismatch, and the leverage of the temporal (e.g., recency and burst nature) and contextual characteristics of tweets. To address the temporal and contextual aspect of tweets, we propose new features based on query-tweet time, word embedding, and query-tweet sentiment correlation. We also introduce some popularity features to estimate the importance of a tweet. A three-stage query expansion technique is applied to improve the relevancy of tweets. Moreover, to determine the temporal and sentiment sensitivity of a query, we introduce query type determination techniques. After supervised feature selection, we apply random forest as a feature ranking method to estimate the importance of selected features. Then, we make use of ensemble of learning to rank (L2R) framework to estimate the relevance of query-tweet pair. We conducted experiments on TREC Microblog 2011 and 2012 test collections over the TREC Tweets2011 corpus. Experimental results demonstrate the effectiveness of our method over the baseline and known related works in terms of precision at 30 (P@30), mean average precision (MAP), normalized discounted cumulative gain at 30 (NDCG@30), and R-precision (R-Prec) metrics. key words: microblog search, temporal information retrieval, query expansion, feature selection, learning to rank, time-aware ranking
IntroductionNowadays, microblog web sites are not only the places in maintaining the social relationships, but also act as a valuable information source. Everyday lots of users turn into microblog sites for sharing their views, opinions, experiences, important news, and also want to get some information what is happening around the world. Among several microblog sites, Twitter * is now the most popular, where lots of users post tweets whenever a notable event occurs. That is why; information retrieval in twitter has made a hit with a lot of complaisance. By searching tweets, users find temporally relevant information, such as breaking news and real-time events [1]. That means, freshness (i.e. recency) of the tweet with respect to query time is an important factor of rele- vance. Another important characteristic of twitter is that people tends to post about a topic within a specific period of time (i.e. bursty nature). For example, when the breakup news of famous band "White Stripes" published on 2nd Feb, 2011, many people post tweets about this topic on that day. That is why; posts that are generate...