I'm a first year PhD. student working with Prof. Andrew McCallum and his excellent group of students!. I completed my Master's from the Language Technologies Institute at Carnegie Mellon University. There I had a lot of fun working with Prof. Chris Dyer and Prof. Norman Sadeh. I got my Bachelor's in Computer Science from NIT Calicut, India
I spent a year in the fantastic Bay Area working as a Machine Learning Engineer at @WalmartLabs
Our goal is to combine the rich multi-step inference of symbolic logical reasoning together with the generalization capabilities of vector embeddings and neural networks. We are particularly interested in complex reasoning about the entities and relations in knowledge bases. Recently Neelakantan et al. (2015) presented a compelling methodology using recurrent neural networks (RNNs) to compose the meaning of relations in a Horn clause consisting of a connected chain. However, this work has multiple weaknesses: it accounts for relations but not entities; it limits generalization by training many separate models; it does not combine evidence over multiple paths. In this paper we address all these weaknesses, making key strides towards our goal of rich logical reasoning with neural networks: our RNN leverages and jointly trains both relation and entity type embeddings, we train a single high-capacity RNN to compose Horn clause chains across all predicted relation types; we demonstrate that pooling evidence across multiple chains can dramatically improve both speed of training and final accuracy. We also explore multi-task training of entity and relation types. On a large dataset from ClueWeb and Freebase our approach provides a significant increase in mean average precision from 55.3% to 73.2%
Continuous space word embeddings learned from large, unstructured corpora have been shown to be effective at capturing semantic regularities in language. In this paper we replace LDA's parameterization of "topics" as categorical distributions over opaque word types with multivariate Gaussian distributions on the embedding space. This encourages the model to group words that are a-priori known to be semantically related into topics. To perform inference, we introduce a fast collapsed Gibbs sampling algorithm based on Cholesky decompositions of covariance matrices of the posterior predictive distributions. We further derive a scalable algorithm that draws samples from stale posterior predictive distributions and corrects them with a Metropolis--Hastings step. Using vectors learned from a domain-general corpus (English Wikipedia), we report results on two document collections (20-newsgroups and NIPS). Qualitatively, Gaussian LDA infers different (but still very sensible) topics relative to standard LDA. Quantitatively, our technique outperforms existing models at dealing with OOV words in held-out documents.
Relation extraction is one of the core challenges in automated knowledge base construction. One line of approach for relation extraction is to perform multi-hop reasoning on the paths connecting an entity pair to infer new relations. While these methods have been successfully applied for knowledge base completion, they do not utilize the entity or the entity type information to make predictions. In this work, we incorporate selectional preferences, i.e., relations enforce constraints on the allowed entity types for the candidate entities, to multi-hop relation extraction by including entity type information. We achieve a 17:67% improvement in MAP score in a relation extractiontask when compared to a method that does not use entity type information.