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Notes on the Behavior of MC Dropout

arXiv.org Machine Learning

The increasing interest in the deployment of deep learning solutions in real safety-critical applications ranging from hearthcare to robotics and autonomous vehicles is making apparent the importance to properly estimate the uncertainty of the predictions made by deep neural networks [1, 2]. While most common neural network architectures only provide point estimates, uncertainty can be evaluated with Bayesian neural networks (BNNs) [3, 4] where the deterministic weights used in the majority of neural networks are replaced with distributions over the network parameters. Although the formulation of BNNs is relatively easy in theory, their use in practise for most complex problems is often unfeasible due to their need to analytically evaluate the marginal probabilies during training which becomes quickly intractable. Recently, variational inference methods have been proposed as a practical alternative to BNNs, but most of these formulations requires double the number of parameters of a network to represent its uncertainty which leads to increased computational costs [5, 6]. Another very popular option to model uncertainty in deep neural networks is the use of dropout as a way to approximate Bayesian variational inference [6].


Communication-Efficient and Distributed Learning Over Wireless Networks: Principles and Applications

arXiv.org Machine Learning

Machine learning (ML) is a promising enabler for the fifth generation (5G) communication systems and beyond. By imbuing intelligence into the network edge, edge nodes can proactively carry out decision-making, and thereby react to local environmental changes and disturbances while experiencing zero communication latency. To achieve this goal, it is essential to cater for high ML inference accuracy at scale under time-varying channel and network dynamics, by continuously exchanging fresh data and ML model updates in a distributed way. Taming this new kind of data traffic boils down to improving the communication efficiency of distributed learning by optimizing communication payload types, transmission techniques, and scheduling, as well as ML architectures, algorithms, and data processing methods. To this end, this article aims to provide a holistic overview of relevant communication and ML principles, and thereby present communication-efficient and distributed learning frameworks with selected use cases.


Federated Transfer Learning with Dynamic Gradient Aggregation

arXiv.org Machine Learning

In this paper, a Federated Learning (FL) simulation platform is introduced. The target scenario is Acoustic Model training based on this platform. To our knowledge, this is the first attempt to apply FL techniques to Speech Recognition tasks due to the inherent complexity. The proposed FL platform can support different tasks based on the adopted modular design. As part of the platform, a novel hierarchical optimization scheme and two gradient aggregation methods are proposed, leading to almost an order of magnitude improvement in training convergence speed compared to other distributed or FL training algorithms like BMUF and FedAvg. The hierarchical optimization offers additional flexibility in the training pipeline besides the enhanced convergence speed. On top of the hierarchical optimization, a dynamic gradient aggregation algorithm is proposed, based on a data-driven weight inference. This aggregation algorithm acts as a regularizer of the gradient quality. Finally, an unsupervised training pipeline tailored to FL is presented as a separate training scenario. The experimental validation of the proposed system is based on two tasks: first, the LibriSpeech task showing a speed-up of 7x and 6% Word Error Rate reduction (WERR) compared to the baseline results. The second task is based on session adaptation providing an improvement of 20% WERR over a competitive production-ready LAS model. The proposed Federated Learning system is shown to outperform the golden standard of distributed training in both convergence speed and overall model performance.


Training DNN Model with Secret Key for Model Protection

arXiv.org Machine Learning

In this paper, we propose a model protection method by using block-wise pixel shuffling with a secret key as a preprocessing technique to input images for the first time. The protected model is built by training with such preprocessed images. Experiment results show that the performance of the protected model is close to that of non-protected models when the key is correct, while the accuracy is severely dropped when an incorrect key is given, and the proposed model protection is robust against not only brute-force attacks but also fine-tuning attacks, while maintaining almost the same performance accuracy as that of using a non-protected model.


Self-Supervised Contrastive Learning for Unsupervised Phoneme Segmentation

arXiv.org Machine Learning

We propose a self-supervised representation learning model for the task of unsupervised phoneme boundary detection. The model is a convolutional neural network that operates directly on the raw waveform. It is optimized to identify spectral changes in the signal using the Noise-Contrastive Estimation principle. At test time, a peak detection algorithm is applied over the model outputs to produce the final boundaries. As such, the proposed model is trained in a fully unsupervised manner with no manual annotations in the form of target boundaries nor phonetic transcriptions. We compare the proposed approach to several unsupervised baselines using both TIMIT and Buckeye corpora. Results suggest that our approach surpasses the baseline models and reaches state-of-the-art performance on both data sets. Furthermore, we experimented with expanding the training set with additional examples from the Librispeech corpus. We evaluated the resulting model on distributions and languages that were not seen during the training phase (English, Hebrew and German) and showed that utilizing additional untranscribed data is beneficial for model performance.


Improving the Accuracy of Global Forecasting Models using Time Series Data Augmentation

arXiv.org Artificial Intelligence

Forecasting models that are trained across sets of many time series, known as Global Forecasting Models (GFM), have shown recently promising results in forecasting competitions and real-world applications, outperforming many state-of-the-art univariate forecasting techniques. In most cases, GFMs are implemented using deep neural networks, and in particular Recurrent Neural Networks (RNN), which require a sufficient amount of time series to estimate their numerous model parameters. However, many time series databases have only a limited number of time series. In this study, we propose a novel, data augmentation based forecasting framework that is capable of improving the baseline accuracy of the GFM models in less data-abundant settings. We use three time series augmentation techniques: GRATIS, moving block bootstrap (MBB), and dynamic time warping barycentric averaging (DBA) to synthetically generate a collection of time series. The knowledge acquired from these augmented time series is then transferred to the original dataset using two different approaches: the pooled approach and the transfer learning approach. When building GFMs, in the pooled approach, we train a model on the augmented time series alongside the original time series dataset, whereas in the transfer learning approach, we adapt a pre-trained model to the new dataset. In our evaluation on competition and real-world time series datasets, our proposed variants can significantly improve the baseline accuracy of GFM models and outperform state-of-the-art univariate forecasting methods.


Has OpenAI Surpassed DeepMind?

#artificialintelligence

OpenAI's GPT-3 is the talk of the town, and the media is giving it all the attention. Many analysts are even comparing it to AGI because of its practical applicability. Initially disclosed in a research paper in May, GPT-3 is the next version of GPT-2 and is 100x larger than it. It is far more competent than its forerunner due to the number of parameters it is trained on, which is 175 billion for GPT-3 versus 1.5 billion for GPT-2. After the successful launch of GPT-3, other AI companies seem to have been overshadowed.


VIEW: Digitisation in pathology and the promise of artificial intelligence โ€“ Tech Check News

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The COVID-19 pandemic has had a profound impact across industries and healthcare in particular--every aspect of it is undergoing change--from diagnosis to treatment and through the entire continuum of care. This has also created an urgency in the healthcare industry, to look for innovative solutions and a boost to the faster, efficient application of technologies like Artificial Intelligence (AI) and Deep Learning. Pathology is one area which stands to greatly benefit from these applications.


Artificial Intelligence: Trends & Applications To Watch In 2020 - Simpliv Blog

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For movie buffs, the work that the factory machines do in Charlie Chaplin's 1936 classic, Modern Times, may have seemed too futuristic for its time. Fast forward eight decades, and the colossal changes that Artificial Intelligence is catalyzing around us will most likely give the same impression to our future generations. There is one crucial difference though: while those advancements were in movies, what we are seeing today are real. A question that seems to be on everyone's mind is, What is Artificial Intelligence? The pace at which AI is moving, as well as the breadth and scope of the areas it encompasses, ensure that it is going to change our lives beyond the normal.


The Next AI Frontier โ€“ Software That Writes Software - Liwaiwai

#artificialintelligence

Depending on your opinion, Artificial Intelligence is either a threat or the next big thing. Even though its deep learning capabilities are being applied to help solve large problems, like the treatment and prevention of human and genetic disorders, or small problems, like what movie to stream tonight, AI in many of its forms (such as machine learning, deep learning and cognitive computing) is still in its infancy in terms of being adopted to generate software code. AI is evolving from the stuff of science fiction, research, and limited industry implementations, to adoption across a multitude of fields, including retail, banking, telecoms, insurance, healthcare, and government. However, for the one field ripe for AI adoption โ€“ the software industry โ€“ progress is curiously slow. Consider this: why isn't an industry, which is built on esoteric symbols, machine syntax, and repetitive loops and functions, all-in on automating code?