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 Transfer Learning


Group-Sparse Matrix Factorization for Transfer Learning of Word Embeddings

arXiv.org Machine Learning

Sparse regression has recently been applied to enable transfer learning from very limited data. We study an extension of this approach to unsupervised learning -- in particular, learning word embeddings from unstructured text corpora using low-rank matrix factorization. Intuitively, when transferring word embeddings to a new domain, we expect that the embeddings change for only a small number of words -- e.g., the ones with novel meanings in that domain. We propose a novel group-sparse penalty that exploits this sparsity to perform transfer learning when there is very little text data available in the target domain -- e.g., a single article of text. We prove generalization bounds for our algorithm. Furthermore, we empirically evaluate its effectiveness, both in terms of prediction accuracy in downstream tasks as well as the interpretability of the results.


eGAN: Unsupervised approach to class imbalance using transfer learning

arXiv.org Artificial Intelligence

Class imbalance is an inherent problem in many machine learning classification tasks. This often leads to trained models that are unusable for any practical purpose. In this study we explore an unsupervised approach to address these imbalances by leveraging transfer learning from pre-trained image classification models to encoder-based Generative Adversarial Network (eGAN). To the best of our knowledge, this is the first work to tackle this problem using GAN without needing to augment with synthesized fake images. In the proposed approach we use the discriminator network to output a negative or positive score. We classify as minority, test samples with negative scores and as majority those with positive scores. Our approach eliminates epistemic uncertainty in model predictions, as the P(minority) + P(majority) need not sum up to 1. The impact of transfer learning and combinations of different pre-trained image classification models at the generator and discriminator is also explored. Best result of 0.69 F1-score was obtained on CIFAR-10 classification task with imbalance ratio of 1:2500. Our approach also provides a mechanism of thresholding the specificity or sensitivity of our machine learning system. Keywords: Class imbalance, Transfer Learning, GAN, nash equilibrium


A Concise Review of Transfer Learning

arXiv.org Artificial Intelligence

The availability of abundant labeled data in recent years led the researchers to introduce a methodology called transfer learning, which utilizes existing data in situations where there are difficulties in collecting new annotated data. Transfer learning aims to boost the performance of a target learner by applying another related source data. In contrast to the traditional machine learning and data mining techniques, which assume that the training and testing data lie from the same feature space and distribution, transfer learning can handle situations where there is a discrepancy between domains and distributions. These characteristics give the model the potential to utilize the available related source data and extend the underlying knowledge to the target task achieving better performance. This survey paper aims to give a concise review of traditional and current transfer learning settings, existing challenges, and related approaches.


Understanding Continual Learning Settings with Data Distribution Drift Analysis

arXiv.org Artificial Intelligence

Classical machine learning algorithms often assume that the data are drawn i.i.d. from a stationary probability distribution. Recently, continual learning emerged as a rapidly growing area of machine learning where this assumption is relaxed, namely, where the data distribution is non-stationary, i.e., changes over time. However, data distribution drifts may interfere with the learning process and erase previously learned knowledge; thus, continual learning algorithms must include specialized mechanisms to deal with such distribution drifts. A distribution drift may change the class labels distribution, the input distribution, or both. Moreover, distribution drifts might be abrupt or gradual. In this paper, we aim to identify and categorize different types of data distribution drifts and potential assumptions about them, to better characterize various continual-learning scenarios. Moreover, we propose to use the distribution drift framework to provide more precise definitions of several terms commonly used in the continual learning field.


Transfer Learning in Keras (Image Recognition)

#artificialintelligence

Transfer Learning in AI is a method where a model is developed for a specific task, which is used as the initial steps for another model for other tasks. Deep Convolutional Neural Networks in deep learning take an hour or day to train the mode if the dataset we are playing is vast. The approach is we reuse the weights of the pre-trained model, which was trained for some standard Computer Vision datasets such as Image classification (Image Net). Extensive deep Convolutional networks for large-scale image classification are available in Keras, which we can directly import and can be used with their pre-trained weights. Let's now understand how to use VGG16 pre-trained on 10,000 categories(Image Net) for the Distracted driver Detection dataset.


Pretrained Models for Transfer Learning in Keras for Computer Vision

#artificialintelligence

Tensorflow is one of the highly used libraries for Machine Learning. It has built-in support for Keras. We can easily call functions related to Keras by using the tf.keras module. Computer Vision is one of the most interesting branches of machine learning. The ImageNet dataset was the turning point for researchers related to Computer Vision as it provided a large set of images for Object detection.


OTCE: A Transferability Metric for Cross-Domain Cross-Task Representations

arXiv.org Artificial Intelligence

Transfer learning across heterogeneous data distributions (a.k.a. domains) and distinct tasks is a more general and challenging problem than conventional transfer learning, where either domains or tasks are assumed to be the same. While neural network based feature transfer is widely used in transfer learning applications, finding the optimal transfer strategy still requires time-consuming experiments and domain knowledge. We propose a transferability metric called Optimal Transport based Conditional Entropy (OTCE), to analytically predict the transfer performance for supervised classification tasks in such cross-domain and cross-task feature transfer settings. Our OTCE score characterizes transferability as a combination of domain difference and task difference, and explicitly evaluates them from data in a unified framework. Specifically, we use optimal transport to estimate domain difference and the optimal coupling between source and target distributions, which is then used to derive the conditional entropy of the target task (task difference). Experiments on the largest cross-domain dataset DomainNet and Office31 demonstrate that OTCE shows an average of 21% gain in the correlation with the ground truth transfer accuracy compared to state-of-the-art methods. We also investigate two applications of the OTCE score including source model selection and multi-source feature fusion.


Active Multitask Learning with Committees

arXiv.org Artificial Intelligence

The cost of annotating training data has traditionally been a bottleneck for supervised learning approaches. The problem is further exacerbated when supervised learning is applied to a number of correlated tasks simultaneously since the amount of labels required scales with the number of tasks. To mitigate this concern, we propose an active multitask learning algorithm that achieves knowledge transfer between tasks. The approach forms a so-called committee for each task that jointly makes decisions and directly shares data across similar tasks. Our approach reduces the number of queries needed during training while maintaining high accuracy on test data. Empirical results on benchmark datasets show significant improvements on both accuracy and number of query requests.


neural networks transfer learning and sentiment prediction

#artificialintelligence

How to learn machine learning in python? And what is transfer learning? How to create a sentiment classification algorithm in python? Let's dive into data science! In the world of today and especially tomorrow machine learning will be the driving force of the economy.


A Machine Learning Engineer's Tutorial to Transfer Learning for Multi-class Image Segmentation…

#artificialintelligence

Image semantic segmentation is one of the most significant areas of research and engineering in the computer vision domain. From segmenting pedestrians and cars for autonomous drive [1] to segmentation and localization of pathology in medical images [2], there are several use-cases of image segmentation. With the wide-spread use of deep learning models for end-to-end delivery for machine learning (ML) models, the U-net model has emerged as a scalable solution across autonomous drive and medical imaging use-cases [3–4]. However, most existing papers and methods implement binary classification tasks for detecting objects/regions of interest over the backgrounds [4]. In this hands-on tutorial we will review how to start from a binary semantic segmentation task and transfer the learning to suit multi-class image segmentation tasks.