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 Deep Learning


Introduction to Deep Learning

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This textbook presents a concise, accessible and engaging first introduction to deep learning, offering a wide range of connectionist models which represent the current state-of-the-art. The text explores the most popular algorithms and architectures in a simple and intuitive style, explaining the mathematical derivations in a step-by-step manner. The content coverage includes convolutional networks, LSTMs, Word2vec, RBMs, DBNs, neural Turing machines, memory networks and autoencoders. Numerous examples in working Python code are provided throughout the book, and the code is also supplied separately at an accompanying website. This clearly written and lively primer on deep learning is essential reading for graduate and advanced undergraduate students of computer science, cognitive science and mathematics, as well as fields such as linguistics, logic, philosophy, and psychology.


Neural Networks and Deep Learning

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This book covers both classical and modern models in deep learning. The basics of neural networks: Many traditional machine learning models can be understood as special cases of neural networks. An emphasis is placed in the first two chapters on understanding the relationship between traditional machine learning and neural networks. Support vector machines, linear/logistic regression, singular value decomposition, matrix factorization, and recommender systems are shown to be special cases of neural networks. These methods are studied together with recent feature engineering methods like word2vec.


Introduction to Artificial Intelligence

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This accessible and engaging textbook presents a concise introduction to the exciting field of artificial intelligence (AI). The broad-ranging discussion covers the key subdisciplines within the field, describing practical algorithms and concrete applications in the areas of agents, logic, search, reasoning under uncertainty, machine learning, neural networks, and reinforcement learning. Fully revised and updated, this much-anticipated second edition also includes new material on deep learning. Dr. Wolfgang Ertel is a professor at the Institute for Artificial Intelligence at the Ravensburg-Weingarten University of Applied Sciences, Germany.


Artificial Intelligence Can Categorize Cancer Risk of Lung Nodules

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Computed tomography (CT) scans for people at risk for lung cancer lead to earlier diagnoses and improve survival rates, but they can also lead to overtreatment when suspicious nodules turn out to be benign. A study published in American Journal of Respiratory and Critical Care Medicine indicates that an artificial intelligence strategy can correctly assess and categorize these indeterminate pulmonary nodules (IPNs). When compared to the conventional risk models clinicians currently use, the algorithm developed by the team of researchers in a very large dataset (15,693 nodules) reclassified IPNs into low-risk or high-risk categories in over a third of cancers and benign nodules. "These results suggest the potential clinical utility of this deep learning algorithm to revise the probability of cancer among IPNs aiming to decrease invasive procedures and shorten time to diagnosis," said Pierre Massion, M.D., Cornelius Vanderbilt Chair in Medicine at Vanderbilt University, the study's lead author. Currently, clinicians refer to guidelines issued by the American College of Radiology and the American College of Chest Physicians.


Adversarial AI: Blocking the hidden backdoor in neural networks

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This article is part of our reviews of AI research papers, a series of posts that explore the latest findings in artificial intelligence. Imagine a high-security complex protected by a facial recognition system powered by deep learning. The artificial intelligence algorithm has been tuned to unlock the doors for authorized personnel only, a convenient alternative to fumbling for your keys at every door. A stranger shows up, dons a bizarre set of spectacles, and all of a sudden, the facial recognition system mistakes him for the company's CEO and opens all the doors for him. By installing a backdoor in the deep learning algorithm, the malicious actor ironically gained access to the building through the front door.


RotEqNet: Rotation-Equivariant Network for Fluid Systems with Symmetric High-Order Tensors

arXiv.org Machine Learning

In the recent application of scientific modeling, machine learning models are largely applied to facilitate computational simulations of fluid systems. Rotation symmetry is a general property for most symmetric fluid systems. However, in general, current machine learning methods have no theoretical way to guarantee rotational symmetry. By observing an important property of contraction and rotation operation on high-order symmetric tensors, we prove that the rotation operation is preserved via tensor contraction. Based on this theoretical justification, in this paper, we introduce Rotation-Equivariant Network (RotEqNet) to guarantee the property of rotation-equivariance for high-order tensors in fluid systems. We implement RotEqNet and evaluate our claims through four case studies on various fluid systems. The property of error reduction and rotation-equivariance is verified in these case studies. Results from the comparative study show that our method outperforms conventional methods, which rely on data augmentation.


Automatic Cross-Replica Sharding of Weight Update in Data-Parallel Training

arXiv.org Machine Learning

In data-parallel synchronous training of deep neural networks, different devices (replicas) run the same program with different partitions of the training batch, but weight update computation is repeated on all replicas, because the weights do not have a batch dimension to partition. This can be a bottleneck for performance and scalability in typical language models with large weights, and models with small per-replica batch size which is typical in large-scale training. This paper presents an approach to automatically shard the weight update computation across replicas with efficient communication primitives and data formatting, using static analysis and transformations on the training computation graph. We show this technique achieves substantial speedups on typical image and language models on Cloud TPUs, requiring no change to model code. This technique helps close the gap between traditionally expensive (ADAM) and cheap (SGD) optimizers, as they will only take a small part of training step time and have similar peak memory usage. It helped us to achieve state-of-the-art training performance in Google's MLPerf 0.6 submission.


Scan-based Semantic Segmentation of LiDAR Point Clouds: An Experimental Study

arXiv.org Machine Learning

Autonomous vehicles need to have a semantic understanding of the three-dimensional world around them in order to reason about their environment. State of the art methods use deep neural networks to predict semantic classes for each point in a LiDAR scan. A powerful and efficient way to process LiDAR measurements is to use two-dimensional, image-like projections. In this work, we perform a comprehensive experimental study of image-based semantic segmentation architectures for LiDAR point clouds. We demonstrate various techniques to boost the performance and to improve runtime as well as memory constraints. First, we examine the effect of network size and suggest that much faster inference times can be achieved at a very low cost to accuracy. Next, we introduce an improved point cloud projection technique that does not suffer from systematic occlusions. We use a cyclic padding mechanism that provides context at the horizontal field-of-view boundaries. In a third part, we perform experiments with a soft Dice loss function that directly optimizes for the intersection-over-union metric. Finally, we propose a new kind of convolution layer with a reduced amount of weight-sharing along one of the two spatial dimensions, addressing the large difference in appearance along the vertical axis of a LiDAR scan. We propose a final set of the above methods with which the model achieves an increase of 3.2% in mIoU segmentation performance over the baseline while requiring only 42% of the original inference time.


On the Neural Tangent Kernel of Deep Networks with Orthogonal Initialization

arXiv.org Machine Learning

In recent years, a critical initialization scheme of orthogonal initialization on deep nonlinear networks has been proposed. The orthogonal weights are crucial to achieve {\it dynamical isometry} for random networks, where the entire spectrum of singular values of an input-output Jacobian are around one. The strong empirical evidence that orthogonal initialization in linear networks and the linear regime of nonlinear networks can speed up training than Gaussian initialization raise great interests. One recent work has proven the benefit of orthogonal initialization in linear networks. However, the dynamics behind it have not been revealed on nonlinear networks. In this work, we study the Neural Tangent Kernel (NTK), which can describe dynamics of gradient descent training of wide network, and focus on fully-connected and nonlinear networks with orthogonal initialization. We prove that NTK of Gaussian and orthogonal weights are equal when the network width is infinite, resulting in a conclusion that orthogonal initialization can speed up training is a finite-width effect in the small learning rate regime. Then we find that during training, the NTK of infinite-width network with orthogonal initialization stays constant theoretically and varies at a rate of the same order as Gaussian ones empirically, as the width tends to infinity. Finally, we conduct a thorough empirical investigation of training speed on CIFAR10 datasets and show the benefit of orthogonal initialization lies in the large learning rate and depth phase in a linear regime of nonlinear network.


Train a Deep Learning Text Classifier within Zapier!

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Aasaan.ai has always looked at ways to help people with no technical or data science background to adopt AI and specifically Natural Language Processing. NLP is one domain of AI which can have a direct impact on your customer's experience with your business which may ultimately result in higher retention. The harsh truth is that getting these AI models to work requires substantial knowledge of coding, machine learning, and deep learning. And even if you have the prerequisite knowledge, it can still be a very daunting task. Introducing, Aasaanai for Zapier, a Zapier integration which enables a user to train and use state of the art deep learning text classifiers within 5 minutes!