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 Deep Learning


Learning Latent Representations in Neural Networks for Clustering through Pseudo Supervision and Graph-based Activity Regularization

arXiv.org Machine Learning

In this paper, we propose a novel unsupervised clustering approach exploiting the hidden information that is indirectly introduced through a pseudo classification objective. Specifically, we randomly assign a pseudo parent-class label to each observation which is then modified by applying the domain specific transformation associated with the assigned label. Generated pseudo observation-label pairs are subsequently used to train a neural network with Auto-clustering Output Layer (ACOL) that introduces multiple softmax nodes for each pseudo parent-class. Due to the unsupervised objective based on Graph-based Activity Regularization (GAR) terms, softmax duplicates of each parent-class are specialized as the hidden information captured through the help of domain specific transformations is propagated during training. Ultimately we obtain a k-means friendly latent representation. Furthermore, we demonstrate how the chosen transformation type impacts performance and helps propagate the latent information that is useful in revealing unknown clusters. Our results show state-of-the-art performance for unsupervised clustering tasks on MNIST, SVHN and USPS datasets, with the highest accuracies reported to date in the literature.


Learning Sparse Wavelet Representations

arXiv.org Machine Learning

In this work we propose a method for learning wavelet filters directly from data. We accomplish this by framing the discrete wavelet transform as a modified convolutional neural network. We introduce an autoencoder wavelet transform network that is trained using gradient descent. We show that the model is capable of learning structured wavelet filters from synthetic and real data. The learned wavelets are shown to be similar to traditional wavelets that are derived using Fourier methods. Our method is simple to implement and easily incorporated into neural network architectures. A major advantage to our model is that we can learn from raw audio data.


Metrics for Deep Generative Models

arXiv.org Machine Learning

Neural samplers such as variational autoencoders (VAEs) or generative adversarial networks (GANs) approximate distributions by transforming samples from a simple random source---the latent space---to samples from a more complex distribution represented by a dataset. While the manifold hypothesis implies that the density induced by a dataset contains large regions of low density, the training criterions of VAEs and GANs will make the latent space densely covered. Consequently points that are separated by low-density regions in observation space will be pushed together in latent space, making stationary distances poor proxies for similarity. We transfer ideas from Riemannian geometry to this setting, letting the distance between two points be the shortest path on a Riemannian manifold induced by the transformation. The method yields a principled distance measure, provides a tool for visual inspection of deep generative models, and an alternative to linear interpolation in latent space. In addition, it can be applied for robot movement generalization using previously learned skills. The method is evaluated on a synthetic dataset with known ground truth; on a simulated robot arm dataset; on human motion capture data; and on a generative model of handwritten digits.


Ensemble Methods as a Defense to Adversarial Perturbations Against Deep Neural Networks

arXiv.org Machine Learning

Deep learning has become the state of the art approach in many machine learning problems such as classification. It has recently been shown that deep learning is highly vulnerable to adversarial perturbations. Taking the camera systems of self-driving cars as an example, small adversarial perturbations can cause the system to make errors in important tasks, such as classifying traffic signs or detecting pedestrians. Hence, in order to use deep learning without safety concerns a proper defense strategy is required. We propose to use ensemble methods as a defense strategy against adversarial perturbations. We find that an attack leading one model to misclassify does not imply the same for other networks performing the same task. This makes ensemble methods an attractive defense strategy against adversarial attacks. We empirically show for the MNIST and the CIFAR-10 data sets that ensemble methods not only improve the accuracy of neural networks on test data but also increase their robustness against adversarial perturbations.


An Information-Theoretic Optimality Principle for Deep Reinforcement Learning

arXiv.org Machine Learning

We methodologically address the problem of Q-value overestimation in deep reinforcement learning to handle high-dimensional state spaces efficiently. By adapting concepts from information theory, we introduce an intrinsic penalty signal encouraging reduced Q-value estimates. The resultant algorithm encompasses a wide range of learning outcomes containing deep Q-networks as a special case. Different learning outcomes can be demonstrated by tuning a Lagrange multiplier accordingly. We furthermore propose a novel scheduling scheme for this Lagrange multiplier to ensure efficient and robust learning. In experiments on Atari games, our algorithm outperforms other algorithms (e.g.


Optimization Methods for Large-Scale Machine Learning

arXiv.org Machine Learning

This paper provides a review and commentary on the past, present, and future of numerical optimization algorithms in the context of machine learning applications. Through case studies on text classification and the training of deep neural networks, we discuss how optimization problems arise in machine learning and what makes them challenging. A major theme of our study is that large-scale machine learning represents a distinctive setting in which the stochastic gradient (SG) method has traditionally played a central role while conventional gradient-based nonlinear optimization techniques typically falter. Based on this viewpoint, we present a comprehensive theory of a straightforward, yet versatile SG algorithm, discuss its practical behavior, and highlight opportunities for designing algorithms with improved performance. This leads to a discussion about the next generation of optimization methods for large-scale machine learning, including an investigation of two main streams of research on techniques that diminish noise in the stochastic directions and methods that make use of second-order derivative approximations.


The future of hardware is AI, says director of IBM-Research Almaden

#artificialintelligence

AI workloads are different from the calculations most of our current computers are built to perform. AI implies prediction, inference, intuition. But the most creative machine learning algorithms are hamstrung by machines that can't harness their power. Hence, if we're to make great strides in AI, our hardware must change, too. Let's start in the present, with applying massively distributed deep learning algorithms to Graphics processing units (GPU) for high speed data movement, to ultimately understand images and sound.


IMPALA: Scalable Distributed DeepRL in DMLab-30 DeepMind

#artificialintelligence

The tasks are designed to be as varied as possible. They differ in the goals they target, from learning, to memory, to navigation. They vary visually, from brightly coloured, modern-styled texture, to the subtle brown and greens of a desert at dawn, midday, or by night. And they contain physically different settings, from open, mountainous terrain, to right-angled mazes, to open, circular rooms. In addition, some of the environments include'bots', with their own, internal, goal-oriented behaviours.


Apple Watch, Android Wear Can Detect Early Diabetes Signs Study Says

International Business Times

Researchers say the Apple Watch and Android Wear watches can detect early signs of diabetes, according to large study involving more than 14,000 Cardiogram app users. The study, conducted by researchers at UC San Francisco and Cardiogram, was released on Wednesday. Cardiogram, a digital health startup, was founded in 2016 by ex-Googlers Johnson Hsieh and Brandon Ballinger. The Cardiogram app is available for iOS and Android and is compatible with all Apple Watches and Android Wear devices, including the Huawei Watch, LG Watch Sport, Moto 360 and more. The app has more than 250,000 users.