2,442 research outputs found
Approximating Word Ranking and Negative Sampling for Word Embedding
CBOW (Continuous Bag-Of-Words) is one of the most commonly used techniques to generate word embeddings in various NLP tasks. However, it fails to reach the optimal performance due to uniform involvements of positive words and a simple sampling distribution of negative words. To resolve these issues, we propose OptRank to optimize word ranking and approximate negative sampling for bettering word embedding. Specifically, we first formalize word embedding as a ranking problem. Then, we weigh the positive words by their ranks such that highly ranked words have more importance, and adopt a dynamic sampling strategy to select informative negative words. In addition, an approximation method is designed to efficiently compute word ranks. Empirical experiments show that OptRank consistently outperforms its counterparts on a benchmark dataset with different sampling scales, especially when the sampled subset is small. The code and datasets can be obtained from https://github.com/ouououououou/OptRank
Learning Graph Embeddings from WordNet-based Similarity Measures
We present path2vec, a new approach for learning graph embeddings that relies
on structural measures of pairwise node similarities. The model learns
representations for nodes in a dense space that approximate a given
user-defined graph distance measure, such as e.g. the shortest path distance or
distance measures that take information beyond the graph structure into
account. Evaluation of the proposed model on semantic similarity and word sense
disambiguation tasks, using various WordNet-based similarity measures, show
that our approach yields competitive results, outperforming strong graph
embedding baselines. The model is computationally efficient, being orders of
magnitude faster than the direct computation of graph-based distances.Comment: Accepted to StarSem 201
Relaxed Softmax for learning from Positive and Unlabeled data
In recent years, the softmax model and its fast approximations have become
the de-facto loss functions for deep neural networks when dealing with
multi-class prediction. This loss has been extended to language modeling and
recommendation, two fields that fall into the framework of learning from
Positive and Unlabeled data. In this paper, we stress the different drawbacks
of the current family of softmax losses and sampling schemes when applied in a
Positive and Unlabeled learning setup. We propose both a Relaxed Softmax loss
(RS) and a new negative sampling scheme based on Boltzmann formulation. We show
that the new training objective is better suited for the tasks of density
estimation, item similarity and next-event prediction by driving uplifts in
performance on textual and recommendation datasets against classical softmax.Comment: 9 pages, 5 figures, 2 tables, published at RecSys 201
Multimodal Machine Learning for Automated ICD Coding
This study presents a multimodal machine learning model to predict ICD-10
diagnostic codes. We developed separate machine learning models that can handle
data from different modalities, including unstructured text, semi-structured
text and structured tabular data. We further employed an ensemble method to
integrate all modality-specific models to generate ICD-10 codes. Key evidence
was also extracted to make our prediction more convincing and explainable. We
used the Medical Information Mart for Intensive Care III (MIMIC -III) dataset
to validate our approach. For ICD code prediction, our best-performing model
(micro-F1 = 0.7633, micro-AUC = 0.9541) significantly outperforms other
baseline models including TF-IDF (micro-F1 = 0.6721, micro-AUC = 0.7879) and
Text-CNN model (micro-F1 = 0.6569, micro-AUC = 0.9235). For interpretability,
our approach achieves a Jaccard Similarity Coefficient (JSC) of 0.1806 on text
data and 0.3105 on tabular data, where well-trained physicians achieve 0.2780
and 0.5002 respectively.Comment: Machine Learning for Healthcare 201
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