Similarity-Based Approaches to Natural Language Processing
<|reference_start|>Similarity-Based Approaches to Natural Language Processing: This thesis presents two similarity-based approaches to sparse data problems. The first approach is to build soft, hierarchical clusters: soft, because each event belongs to each cluster with some probability; hierarchical, because cluster centroids are iteratively split to model finer distinctions. Our second approach is a nearest-neighbor approach: instead of calculating a centroid for each class, as in the hierarchical clustering approach, we in essence build a cluster around each word. We compare several such nearest-neighbor approaches on a word sense disambiguation task and find that as a whole, their performance is far superior to that of standard methods. In another set of experiments, we show that using estimation techniques based on the nearest-neighbor model enables us to achieve perplexity reductions of more than 20 percent over standard techniques in the prediction of low-frequency events, and statistically significant speech recognition error-rate reduction.<|reference_end|>
@article{lee1997similarity-based,
    title={Similarity-Based Approaches to Natural Language Processing},
    author={Lillian Lee (Cornell University)},
    journal={arXiv preprint arXiv:cmp-lg/9708011},
    year={1997},
    number={Harvard University Technical Report TR-11-97},
    archivePrefix={arXiv},
    eprint={cmp-lg/9708011},
    primaryClass={cmp-lg cs.CL}
}