Introduction | was extended from the latent Dirichlet allocation ( LDA ) model (?) |
Joint Sentiment-Topic (J ST) Model | It is worth pointing out that the J ST model with single topic becomes the standard LDA model with only three sentiment topics. |
Joint Sentiment-Topic (J ST) Model | that the J ST model with word polarity priors incorporated performs significantly better than the LDA model without incorporating such prior information. |
Joint Sentiment-Topic (J ST) Model | For comparison purpose, we also run the LDA model and augmented the BOW features with the |
Abstract | In this work, we develop a framework for allowing users to iteratively refine the topics discovered by models such as latent Dirichlet allocation ( LDA ) by adding constraints that enforce that sets of words must appear together in the same topic. |
Constraints Shape Topics | As discussed above, LDA views topics as distributions over words, and each document expresses an admixture of these topics. |
Constraints Shape Topics | For “vanilla” LDA (no constraints), these are symmetric Dirichlet distributions. |
Constraints Shape Topics | Because LDA assumes a document’s tokens are interchangeable, it treats the document as a bag-of—words, ignoring potential relations between words. |
Introduction | Probabilistic topic models, as exemplified by probabilistic latent semantic indexing (Hofmann, 1999) and latent Dirichlet allocation ( LDA ) (Blei et al., 2003) are unsupervised statistical techniques to discover the thematic topics that permeate a large corpus of text documents. |
Putting Knowledge in Topic Models | At a high level, topic models such as LDA take as input a number of topics K and a corpus. |
Putting Knowledge in Topic Models | In LDA both of these outputs are multinomial distributions; typically they are presented to users in summary form by listing the elements with highest probability. |
Experiments | Latent Dirichlet Allocation ( LDA ; Blei et al., 2003) We use the method described in section 2 for inducing word representations from the topic matrix. |
Experiments | To train the 50-topic LDA model we use code released by Blei et a1. |
Experiments | We use the same 5,000 term vocabulary for LDA as is used for training word vector models. |
Our Model | This component does not require labeled data, and shares its foundation with probabilistic topic models such as LDA . |
Our Model | Equation 1 resembles the probabilistic model of LDA (Blei et al., 2003), which models documents as mixtures of latent topics. |
Our Model | Because of the log-linear formulation of the conditional distribution, 6 is a vector in R5 and not restricted to the unit simplex as it is in LDA . |
Related work | Latent Dirichlet Allocation ( LDA ; (Blei et al., 2003)) is a probabilistic document model that assumes each document is a mixture of latent topics. |
Related work | However, because the emphasis in LDA is on modeling topics, not word meanings, there is no guarantee that the row (word) vectors are sensible as points in a k-dimensional space. |
Related work | Indeed, we show in section 4 that using LDA in this way does not deliver robust word vectors. |
Learning Templates from Raw Text | We consider two unsupervised algorithms: Latent Dirichlet Allocation ( LDA ) (Blei et al., 2003), and agglomerative clustering based on word distance. |
Learning Templates from Raw Text | 4.1.1 LDA for Unknown Data |
Learning Templates from Raw Text | LDA is a probabilistic model that treats documents as mixtures of topics. |
Semi-Supervised SimHash | Clearly, Equation (12) is analogous to Linear Discriminant Analysis ( LDA ) (Duda et al., 2000) except for the difference: 1) measurement. |
Semi-Supervised SimHash | 83H uses similarity while LDA uses distance. |
Semi-Supervised SimHash | As a result, the objective function of 83H is just the reciprocal of LDA’s . |