UMass at TREC 2004: Notebook
Nasreen AbdulJaleel, James W Allan, W. Bruce Croft, Fernando Díaz, Leah S. Larkey, Xiaoyan Li, Donald Metzler, Mark D. Smucker, Trevor Strohman, Howard R. Turtle, Courtney Wade · 2004
The retrieval model implemented in the Indri search engine is an enhanced version of the model described in [30], which combines the language modeling [35] and inference network [38] approaches to information retrieval. The resulting model allows structured queries similar to those used in INQUERY [4] to be evaluated using language modeling estimates within the network, rather than tf.idf estimates. Figure 1.1 shows a graphical model representation of the network. As in the original inference network framework, documents are ranked according to P(I|D, α, β), the belief the information need I is met given document D and hyperparameters α and β as evidence. Due to space limitations, a general understanding of the inference network framework is assumed. See [30] and [38] to fill in any missing details. 1.1.1 DOCUMENT REPRESENTATION