This paper briefly describes the Qatar Computing Research Institute (QCRI) participation in the TREC 2011 Microblog track. The focus of our TREC submissions was on using a generative graphic model to perform query expansion. We trained a model that attempted to predict appropriate hashtags to expand tweets as well as queries. In essence, we used hashtags to represent latent topics in tweets.

We present a report on our participation in the English-Indonesian image adhoc task of the 2005 Cross-Language Evaluation Forum (CLEF). We chose to translate the Indonesian query set into English using a commercial machine translation tool called Transtool. We show that some improvement in retrieval effectiveness can be obtained using a query expansion technique. We used an approach that combin...

The generalized Taylor expansion including a secret auxiliary parameter h which can control and adjust the convergence region of the series is the foundation of the homotopy analysis method proposed by Liao. The secret of h can’t be understood in the frame of the homotopy analysis method. This is a serious shortcoming of Liao’s method. We solve the problem. Through a detailed study of a simple ...

We consider some multivariate rational functions which have (or are conjectured to have) only positive coefficients in their series expansion. We consider an operator that preserves positivity of series coefficients, and apply the inverse of this operator to the rational functions. We obtain new rational functions which seem to have only positive coefficients, whose positivity would imply posit...

In this paper, we report on a series of experiments involving feedback and query expansion. We conclude that query expansion using manually assigned keywords has no advantage over expansion using terms from the text of the document.

We consider halo formation in continuous beams oscillating at natural modes by inspecting particle trajectories. Trajectory equations containing field nonlinearities are derived from a weighted polynomial expansion. We then use perturbational techniques to further analyze particle motion.

In this paper we describe our efforts for TREC 2013 Web track. We focus on evaluating the effectiveness of axiomatic retrieval model on large data collection. Axiomatic approach basically searches for the retrieval functions that satisfy some reasonable retrieval constraints. We also evaluate the semantic term matching method which does the query expansion by choosing the semantically related t...