MUTUALINFORMATION MAXIMIZATION Deep InfoMax (DIM, Hjelm et al., 2019) is a recent approach for unsupervised representation learning that derives embeddings by maximizing the mutual information between the output of an encoder and local patches of the input. DIM builds on Mutual Information Neural Information (MINE, Belghazi et al., 2018), which formulates an estimate Î(X; Y) for the mutual information between random variables X, Y using neural networks. These estimates are obtained by training a classifier (a.k.a, the discriminator or statistics network) to distinguish between samples from the joint distribution and the product of marginals. DIM applies this approach to representation learning by training both the encoder and the discriminator to maximize the mutual information between the random variables corresponding to local input patches and the embeddings. Deep Graph Infomax (DGI) extends this representation learning technique to non-temporal graphs, finding node embeddings that maximize the mutual information between local patches of the graph and summaries of the entire graph. Here, we build on these methods and propose a representation learning technique for spatiotemporal graphs. Furthermore, unlike in previous work, we evaluate our embeddings in the regression rather than classification setting.

Proposed in 1991, Least Mean Square Error Reconstruction for self-organizing network, shortly Lmser, was a further development of the traditional auto-encoder (AE) by folding the architecture with respect to the central coding layer and thus leading to the features of symmetric weights and neurons, as well as jointly supervised and unsupervised learning. However, its advantages were only demonstrated in a one-hidden-layer implementation due to the lack of computing resources and big data at that time. In this paper, we revisit Lmser from the perspective of deep learning, develop Lmser network based on multiple convolutional layers, which is more suitable for image-related tasks, and confirm several Lmser functions with preliminary demonstrations on image recognition, reconstruction, association recall, and so on. Experiments demonstrate that Lmser indeed works as indicated in the original paper, and it has promising performance in various applications.

With the increasing interest in deep neural networks, a lot of research work has been focusing lately on their sensitivity to input perturbations [3, 12, 8, 11]. Most of these investigations have highlighted their weakness to handle adversarial attacks and the addressed means to increase their robustness. Adversarial attacks are real threats that could slow down or eventually stop the development and applications of these tools wherever robustness guarantees are needed. If input uncertainty is not adversarial but simply generated by the context and environment of the specific application, deep networks do not show better behavior in terms of robustness. If no immunization mechanism is used, their generalization performance can greatly suffer.

Forecasting the future traffic flow distribution in an area is an importance issue for traffic management in an intelligent transportation system. The key challenge of traffic prediction is to capture spatial and temporal relations between future traffic flows and historical traffic due to highly dynamical patterns of human activities. Most existing methods explore such relations by fusing spatial and temporal features extracted from multi-source data. However, they neglect position information which helps distinguish patterns on different positions. In this paper, we propose a position-aware neural network that integrates data features and position information. Our approach employs the inception backbone network to capture rich features of traffic distribution on the whole area. The novelty lies in that under the backbone network, we apply position embedding technique used in neural language processing to represent position information as embedding vectors which are learned during the training. With these embedding vectors, we design positionaware convolution which allows different kernels to process features of different positions. Extensive experiments on two real-world datasets show that our approach outperforms previous methods even with fewer data sources.

We focus our attention on the problem of generating adversarial perturbations based on the gradient in image classification domain; substantial pixel perturbations make features learned by deep neural networks changed in clean images which fool deep neural models into making incorrect predictions. However, large-scale pixel modification in the image directly makes the changes visible although attack process success. To find the optimal perturbations which can quantify the boundary distance directly between clean images and adversarial examples in latent space, we propose a novel method for integrated adversarial perturbations generation, which formulate adversarial perturbations in the adaptive and integrated gradient level. Our approach calls few adaptive gradient operators to seek the decision boundary between original images and corresponding adversarial examples directly. We compare our proposed method for crafting adversarial perturbations with other state-of-the-art gradient-based attack methods. Experimental results suggest that adversarial samples generated by our approach show excellent efficiency in fooling deep neural classification networks with lower pixel modification and good transferability on image classification models.

In this paper we propose a novel accurate method for dead-reckoning of wheeled vehicles based only on an Inertial Measurement Unit (IMU). In the context of intelligent vehicles, robust and accurate dead-reckoning based on the IMU may prove useful to correlate feeds from imaging sensors, to safely navigate through obstructions, or for safe emergency stops in the extreme case of exteroceptive sensors failure. The key components of the method are the Kalman filter and the use of deep neural networks to dynamically adapt the noise parameters of the filter. The method is tested on the KITTI odometry dataset, and our dead-reckoning inertial method based only on the IMU accurately estimates 3D position, velocity, orientation of the vehicle and self-calibrates the IMU biases. We achieve on average a 1.10% translational error and the algorithm competes with top-ranked methods which, by contrast, use LiDAR or stereo vision. We make our implementation open-source at: https://github.com/mbrossar/ai-imu-dr

Deep Learning techniques have achieved remarkable results in many domains. Often, training deep learning models requires large datasets, which may require sensitive information to be uploaded to the cloud to accelerate training. To adequately protect sensitive information, we propose distributed layer-partitioned training with step-wise activation functions for privacy-preserving deep learning. Experimental results attest our method to be simple and effective.

Most digital cameras use sensors coated with a Color Filter Array (CFA) to capture channel components at every pixel location, resulting in a mosaic image that does not contain pixel values in all channels. Current research on reconstructing these missing channels, also known as demosaicing, introduces many artifacts, such as zipper effect and false color. Many deep learning demosaicing techniques outperform other classical techniques in reducing the impact of artifacts. However, most of these models tend to be over-parametrized. Consequently, edge implementation of the state-of-the-art deep learning-based demosaicing algorithms on low-end edge devices is a major challenge. We provide an exhaustive search of deep neural network architectures and obtain a pareto front of Color Peak Signal to Noise Ratio (CPSNR) as the performance criterion versus the number of parameters as the model complexity that beats the state-of-the-art. Architectures on the pareto front can then be used to choose the best architecture for a variety of resource constraints. Simple architecture search methods such as exhaustive search and grid search requires some conditions of the loss function to converge to the optimum. We clarify these conditions in a brief theoretical study.

Automatically reasoning about future human behaviors is a difficult problem with significant practical applications to assistive systems. Part of this difficulty stems from learning systems' inability to represent all kinds of behaviors. Some behaviors, such as motion, are best described with continuous representations, whereas others, such as picking up a cup, are best described with discrete representations. Furthermore, human behavior is generally not fixed: people can change their habits and routines. This suggests these systems must be able to learn and adapt continuously. In this work, we develop an efficient deep generative model to jointly forecast a person's future discrete actions and continuous motions. On a large-scale egocentric dataset, EPIC-KITCHENS, we observe our method generates high-quality and diverse samples while exhibiting better generalization than related generative models. Finally, we propose a variant to continually learn our model from streaming data, observe its practical effectiveness, and theoretically justify its learning efficiency.

Social media offer an abundant source of valuable raw data, however informal writing can quickly become a bottleneck for many natural language processing (NLP) tasks. Off-the-shelf tools are usually trained on formal text and cannot explicitly handle noise found in short online posts. Moreover, the variety of frequently occurring linguistic variations presents several challenges, even for humans who might not be able to comprehend the meaning of such posts, especially when they contain slang and abbreviations. Text Normalization aims to transform online user-generated text to a canonical form. Current text normalization systems rely on string or phonetic similarity and classification models that work on a local fashion. We argue that processing contextual information is crucial for this task and introduce a social media text normalization hybrid word-character attention-based encoder-decoder model that can serve as a pre-processing step for NLP applications to adapt to noisy text in social media. Our character-based component is trained on synthetic adversarial examples that are designed to capture errors commonly found in online user-generated text. Experiments show that our model surpasses neural architectures designed for text normalization and achieves comparable performance with state-of-the-art related work.