Deep Learning
Multi-GPU Training in Pytorch
Let's say you have 3 GPUs available and you want to train a model on one of them. To allow Pytorch to "see" all available GPUs, use: There are a few different ways to use multiple GPUs, including data parallelism and model parallelism. Data parallelism refers to using multiple GPUs to increase the number of examples processed simultaneously. For example, if a batch size of 256 fits on one GPU, you can use data parallelism to increase the batch size to 512 by using two GPUs, and Pytorch will automatically assign 256 examples to one GPU and 256 examples to the other GPU. Using data parallelism can be accomplished easily through DataParallel.
Accelerating Wide & Deep Recommender Inference on GPUs NVIDIA Developer Blog
Recommendation systems drive engagement on many of the most popular online platforms. As the growth in the volume of data available to power these systems accelerates rapidly, data scientists are increasingly turning from more traditional machine learning methods to highly expressive deep learning models to improve the quality of their recommendations. Google's Wide & Deep architecture has emerged as a popular choice of model for these problems, both for its robustness to signal sparsity, as well as its user-friendly implementation in TensorFlow via the DNNLinearCombinedClassifier API. While the cost and latency induced by the complexity of these deep learning models can be initially very expensive for inference applications, we'll show that an accelerated, mixed-precision implementation of them optimized for NVIDIA GPUs can drastically reduce latency while obtaining impressive improvements in cost/inference. This paves the way for fast, low-cost, scalable recommendation systems well suited to both online and offline deployment and implemented using simple and familiar TensorFlow APIs. In this blog, we describe a highly optimized, GPU-accelerated inference implementation of the Wide & Deep architecture based on TensorFlow's DNNLinearCombinedClassifier API. The solution we propose allows for easy conversion from a trained TensorFlow Wide & Deep model to a mixed precision inference deployment. We also present performance results of this solution based on a representative dataset and show that GPU inference for Wide & Deep models can produce up to a 13x reduction in latency or a 11x throughput improvement in online and offline scenarios respectively. While we all likely have an intuitive understanding of what it is to make a recommendation, the question of how a machine learning model might make one is much less obvious. After all, there is something very prescriptive about the concept of a recommendation: "you should watch movie A", "you should eat the tagliatelle at restaurant B".
Accelerating Wide & Deep Recommender Inference on GPUs NVIDIA Developer Blog
Recommendation systems drive engagement on many of the most popular online platforms. As the growth in the volume of data available to power these systems accelerates rapidly, data scientists are increasingly turning from more traditional machine learning methods to highly expressive deep learning models to improve the quality of their recommendations. Google's Wide & Deep architecture has emerged as a popular choice of model for these problems, both for its robustness to signal sparsity, as well as its user-friendly implementation in TensorFlow via the DNNLinearCombinedClassifier API. While the cost and latency induced by the complexity of these deep learning models can be initially very expensive for inference applications, we'll show that an accelerated, mixed-precision implementation of them optimized for NVIDIA GPUs can drastically reduce latency while obtaining impressive improvements in cost/inference. This paves the way for fast, low-cost, scalable recommendation systems well suited to both online and offline deployment and implemented using simple and familiar TensorFlow APIs. In this blog, we describe a highly optimized, GPU-accelerated inference implementation of the Wide & Deep architecture based on TensorFlow's DNNLinearCombinedClassifier API. The solution we propose allows for easy conversion from a trained TensorFlow Wide & Deep model to a mixed precision inference deployment. We also present performance results of this solution based on a representative dataset and show that GPU inference for Wide & Deep models can produce up to a 13x reduction in latency or a 11x throughput improvement in online and offline scenarios respectively. While we all likely have an intuitive understanding of what it is to make a recommendation, the question of how a machine learning model might make one is much less obvious. After all, there is something very prescriptive about the concept of a recommendation: "you should watch movie A", "you should eat the tagliatelle at restaurant B".
Wide-minima Density Hypothesis and the Explore-Exploit Learning Rate Schedule
Iyer, Nikhil, Thejas, V, Kwatra, Nipun, Ramjee, Ramachandran, Sivathanu, Muthian
While the generalization properties of neural networks are not yet well understood, several papers argue that wide minima generalize better than narrow minima. In this paper, through detailed experiments that not only corroborate the generalization properties of wide minima, we also provide empirical evidence for a new hypothesis that the density of wide minima is likely lower than the density of narrow minima. Further, motivated by this hypothesis, we design a novel explore-exploit learning rate schedule. On a variety of image and natural language datasets, compared to their original hand-tuned learning rate baselines, we show that our explore-exploit schedule can result in either up to 0.5\% higher absolute accuracy using the original training budget or up to 44\% reduced training time while achieving the original reported accuracy.
On the Road with 16 Neurons: Mental Imagery with Bio-inspired Deep Neural Networks
This paper proposes a strategy for visual prediction in the context of autonomous driving. Humans, when not distracted or drunk, are still the best drivers you can currently find. For this reason we take inspiration from two theoretical ideas about the human mind and its neural organization. The first idea concerns how the brain uses a hierarchical structure of neuron ensembles to extract abstract concepts from visual experience and code them into compact representations. The second idea suggests that these neural perceptual representations are not neutral but functional to the prediction of the future state of affairs in the environment. Similarly, the prediction mechanism is not neutral but oriented to the current planning of a future action. We identify within the deep learning framework two artificial counterparts of the aforementioned neurocognitive theories. We find a correspondence between the first theoretical idea and the architecture of convolutional autoencoders, while we translate the second theory into a training procedure that learns compact representations which are not neutral but oriented to driving tasks, from two distinct perspectives. From a static perspective, we force groups of neural units in the compact representations to distinctly represent specific concepts crucial to the driving task. From a dynamic perspective, we encourage the compact representations to be predictive of how the current road scenario will change in the future. We successfully learn compact representations that use as few as 16 neural units for each of the two basic driving concepts we consider: car and lane. We prove the efficiency of our proposed perceptual representations on the SYNTHIA dataset. Our source code is available at https://github.com/3lis/rnn_vae
Supervised Domain Adaptation using Graph Embedding
Hedegaard, Lukas, Sheikh-Omar, Omar Ali, Iosifidis, Alexandros
Getting deep convolutional neural networks to perform well requires a large amount of training data. When the available labelled data is small, it is often beneficial to use transfer learning to leverage a related larger dataset (source) in order to improve the performance on the small dataset (target). Among the transfer learning approaches, domain adaptation methods assume that distributions between the two domains are shifted and attempt to realign them. In this paper, we consider the domain adaptation problem from the perspective of dimensionality reduction and propose a generic framework based on graph embedding. Instead of solving the generalised eigenvalue problem, we formulate the graph-preserving criterion as a loss in the neural network and learn a domain-invariant feature transformation in an end-to-end fashion. We show that the proposed approach leads to a powerful Domain Adaptation framework; a simple LDA-inspired instantiation of the framework leads to state-of-the-art performance on two of the most widely used Domain Adaptation benchmarks, Office31 and MNIST to USPS datasets.
FusionLane: Multi-Sensor Fusion for Lane Marking Semantic Segmentation Using Deep Neural Networks
Yin, Ruochen, Yu, Biao, Wu, Huapeng, Song, Yutao, Niu, Runxin
It is a crucial step to achieve effective semantic segmentation of lane marking during the construction of the lane level high-precision map. In recent years, many image semantic segmentation methods have been proposed. These methods mainly focus on the image from camera, due to the limitation of the sensor itself, the accurate three-dimensional spatial position of the lane marking cannot be obtained, so the demand for the lane level high-precision map construction cannot be met. This paper proposes a lane marking semantic segmentation method based on LIDAR and camera fusion deep neural network. Different from other methods, in order to obtain accurate position information of the segmentation results, the semantic segmentation object of this paper is a bird's eye view converted from a LIDAR points cloud instead of an image captured by a camera. This method first uses the deeplabv3+ [\ref{ref:1}] network to segment the image captured by the camera, and the segmentation result is merged with the point clouds collected by the LIDAR as the input of the proposed network. In this neural network, we also add a long short-term memory (LSTM) structure to assist the network for semantic segmentation of lane markings by using the the time series information. The experiments on more than 14,000 image datasets which we have manually labeled and expanded have shown the proposed method has better performance on the semantic segmentation of the points cloud bird's eye view. Therefore, the automation of high-precision map construction can be significantly improved. Our code is available at https://github.com/rolandying/FusionLane.
Variational Inference for Deep Probabilistic Canonical Correlation Analysis
Karami, Mahdi, Schuurmans, Dale
In this paper, we propose a deep probabilistic multi-view model that is composed of a linear multi-view layer based on probabilistic canonical correlation analysis (CCA) description in the latent space together with deep generative networks as observation models. The network is designed to decompose the variations of all views into a shared latent representation and a set of view-specific components where the shared latent representation is intended to describe the common underlying sources of variation among the views. An efficient variational inference procedure is developed that approximates the posterior distributions of the latent probabilistic multi-view layer while taking into account the solution of probabilistic CCA. A generalization to models with arbitrary number of views is also proposed. The empirical studies confirm that the proposed deep generative multi-view model can successfully extend deep variational inference to multi-view learning while it efficiently integrates the relationship between multiple views to alleviate the difficulty of learning.
Generating Natural Language Adversarial Examples on a Large Scale with Generative Models
Ren, Yankun, Lin, Jianbin, Tang, Siliang, Zhou, Jun, Yang, Shuang, Qi, Yuan, Ren, Xiang
Today text classification models have been widely used. However, these classifiers are found to be easily fooled by adversarial examples. Fortunately, standard attacking methods generate adversarial texts in a pair-wise way, that is, an adversarial text can only be created from a real-world text by replacing a few words. In many applications, these texts are limited in numbers, therefore their corresponding adversarial examples are often not diverse enough and sometimes hard to read, thus can be easily detected by humans and cannot create chaos at a large scale. In this paper, we propose an end to end solution to efficiently generate adversarial texts from scratch using generative models, which are not restricted to perturbing the given texts. We call it unrestricted adversarial text generation. Specifically, we train a conditional variational autoencoder (VAE) with an additional adversarial loss to guide the generation of adversarial examples. Moreover, to improve the validity of adversarial texts, we utilize discrimators and the training framework of generative adversarial networks (GANs) to make adversarial texts consistent with real data. Experimental results on sentiment analysis demonstrate the scalability and efficiency of our method. It can attack text classification models with a higher success rate than existing methods, and provide acceptable quality for humans in the meantime.
An Hybrid Method for the Estimation of the Breast Mechanical Parameters
Lopes, Diogo, Fernandes, António Ramires, Clain, Stéphane
There are several numerical models that describe real phenomena being used to solve complex problems. For example, an accurate numerical breast model can provide assistance to surgeons with visual information of the breast as a result of a surgery simulation. The process of finding the model parameters requires numeric inputs, either based in medical imaging techniques, or other measures. Inputs can be processed by iterative methods (inverse elasticity solvers). Such solvers are highly robust and provide solutions within the required degree of accuracy. However, their computational complexity is costly. On the other hand, machine learning based approaches provide outputs in real-time. Although high accuracy rates can be achieved, these methods are not exempt from producing solutions outside the required degree of accuracy. In the context of real life situations, a non accurate solution might present complications to the patient. We present an hybrid parameter estimation method to take advantage of the positive features of each of the aforementioned approaches. Our method preserves both the real-time performance of deep-learning methods, and the reliability of inverse elasticity solvers. The underlying reasoning behind our proposal is the fact that deep-learning methods, such as neural networks, can provide accurate results in the majority of cases and they just need a fail-safe system to ensure its reliability. Hence, we propose using a Multilayer Neural Networks (MNN) to get an estimation which is in turn validated by a iterative solver. In case the MNN provides an estimation not within the required accuracy range, the solver refines the estimation until the required accuracy is achieved. Based on our results we can conclude that the presented hybrid method is able to complement the computational performance of MNNs with the robustness of iterative solver approaches.