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From Words to Sentences: A Progressive Learning Approach for Zero-resource Machine Translation with Visual Pivots

arXiv.org Artificial Intelligence

The neural machine translation model has suffered from the lack of large-scale parallel corpora. In contrast, we humans can learn multi-lingual translations even without parallel texts by referring our languages to the external world. To mimic such human learning behavior, we employ images as pivots to enable zero-resource translation learning. However, a picture tells a thousand words, which makes multi-lingual sentences pivoted by the same image noisy as mutual translations and thus hinders the translation model learning. In this work, we propose a progressive learning approach for image-pivoted zero-resource machine translation. Since words are less diverse when grounded in the image, we first learn word-level translation with image pivots, and then progress to learn the sentence-level translation by utilizing the learned word translation to suppress noises in image-pivoted multi-lingual sentences. Experimental results on two widely used image-pivot translation datasets, IAPR-TC12 and Multi30k, show that the proposed approach significantly outperforms other state-of-the-art methods.


Weakly Supervised Disentanglement by Pairwise Similarities

arXiv.org Machine Learning

Recently, researches related to unsupervised disentanglement learning with deep generative models have gained substantial popularity. However, without introducing supervision, there is no guarantee that the factors of interest can be successfully recovered [13]. In this paper, we propose a setting where the user introduces weak supervision by providing similarities between instances based on a factor to be disentangled. The similarity is provided as either a discrete (yes/no) or real-valued label describing whether a pair of instances are similar or not. We propose a new method for weakly supervised disentanglement of latent variables within the framework of Variational Autoencoder. Experimental results demonstrate that utilizing weak supervision improves the performance of the disentanglement method substantially.


Towards Unified Acceleration of High-Order Algorithms under H\"{o}lder Continuity and Uniform Convexity

arXiv.org Artificial Intelligence

In this paper, through a very intuitive {\em vanilla proximal method} perspective, we derive accelerated high-order optimization algorithms for minimizing a convex function that has H\"{o}lder continuous derivatives. In this general convex setting, we propose a {\em unified acceleration algorithm} with an iteration complexity that matches the lower iteration complexity bound given in \cite{grapiglia2019tensor}. If the function is further uniformly convex, we propose a {\em general restart scheme}. The iteration complexity of the algorithm matches existing lower bounds in most important cases. For practical implementation, we introduce a new and effective heuristic that significantly simplifies the binary search procedure required by the algorithm, which makes the algorithm in general settings as efficient as the special case \cite{grapiglia2019tensor}. On large-scale classification datasets, our algorithm demonstrates clear and consistent advantages of high-order acceleration methods over first-order ones, in terms of run-time complexity. Our formulation considers the more general composite setting in which the objective function may contain a second possibly non-smooth convex term. Our analysis and proofs are also applicable to the general case in which the high-order smoothness conditions are with respect to non-Euclidean norms.


Self-supervised Body Image Acquisition Using a Deep Neural Network for Sensorimotor Prediction

arXiv.org Machine Learning

This work investigates how a naive agent can acquire its own body image in a self-supervised way, based on the predictability of its sensorimotor experience. Our working hypothesis is that, due to its temporal stability, an agent's body produces more consistent sensory experiences than the environment, which exhibits a greater variability. Given its motor experience, an agent can thus reliably predict what appearance its body should have. This intrinsic predictability can be used to automatically isolate the body image from the rest of the environment. We propose a two-branches deconvolutional neural network to predict the visual sensory state associated with an input motor state, as well as the prediction error associated with this input. We train the network on a dataset of first-person images collected with a simulated Pepper robot, and show how the network outputs can be used to automatically isolate its visible arm from the rest of the environment. Finally, the quality of the body image produced by the network is evaluated.


Neural Network-based Object Classification by Known and Unknown Features (Based on Text Queries)

arXiv.org Machine Learning

The article presents a method that improves the quality of classification of objects described by a combination of known and unknown features. The method is based on modernized Informational Neurobayesian Approach with consideration of unknown features. The proposed method was developed and trained on 1500 text queries of Promobot users in Russian to classify them into 20 categories (classes). As a result, the use of the method allowed to completely solve the problem of misclassification for queries with combining known and unknown features of the model. The theoretical substantiation of the method is presented by the formulated and proved theorem On the Model with Limited Knowledge. It states, that in conditions of limited data, an equal number of equally unknown features of an object cannot have different significance for the classification problem. Keywords: Informational Neurobayesian Approach, Neural describes a car, a race car, or an excavator. Unknown words Networks, Unknown Features, Machine Learning, NLP may bring us closer or farther from these categories. For example, "super-fast"- identifies a race car, and "a dipper" resembles an excavator.


Where is the Information in a Deep Neural Network?

arXiv.org Artificial Intelligence

Whatever information a Deep Neural Network has gleaned from past data is encoded in its weights. How this information affects the response of the network to future data is largely an open question. In fact, even how to define and measure information in a network is still not settled. We introduce the notion of Information in the Weights as the optimal trade-off between accuracy of the network and complexity of the weights, relative to a prior. Depending on the prior, the definition reduces to known information measures such as Shannon Mutual Information and Fisher Information, but affords added flexibility that enables us to relate it to generalization, via the PAC-Bayes bound, and to invariance. This relation hinges not only on the architecture of the model, but surprisingly on how it is trained. We then introduce a notion of effective information in the activations, which are deterministic functions of future inputs, resolving inconsistencies in prior work. We relate this to the Information in the Weights, and use this result to show that models of low complexity not only generalize better, but are bound to learn invariant representations of future inputs.


Robust stability of moving horizon estimation for nonlinear systems with bounded disturbances using adaptive arrival cost

arXiv.org Artificial Intelligence

In this paper, the robust stability and convergence to the true state of moving horizon estimator based on an adaptive arrival cost are established for nonlinear detectable systems. Robust global asymptotic stability is shown for the case of non-vanishing bounded disturbances whereas the convergence to the true state is proved for the case of vanishing disturbances. Several simulations were made in order to show the estimator behaviour under different operational conditions and to compare it with the state of the art estimation methods.


Localization Requirements for Autonomous Vehicles

arXiv.org Artificial Intelligence

Autonomous vehicles require precise knowledge of their position and orientation in all weather and traffic conditions for path planning, perception, control, and general safe operation. Here we derive these requirements for autonomous vehicles based on first principles. We begin with the safety integrity level, defining the allowable probability of failure per hour of operation based on desired improvements on road safety today. This draws comparisons with the localization integrity levels required in aviation and rail where similar numbers are derived at 10^-8 probability of failure per hour of operation. We then define the geometry of the problem, where the aim is to maintain knowledge that the vehicle is within its lane and to determine what road level it is on. Longitudinal, lateral, and vertical localization error bounds (alert limits) and 95% accuracy requirements are derived based on US road geometry standards (lane width, curvature, and vertical clearance) and allowable vehicle dimensions. For passenger vehicles operating on freeway roads, the result is a required lateral error bound of 0.57 m (0.20 m, 95%), a longitudinal bound of 1.40 m (0.48 m, 95%), a vertical bound of 1.30 m (0.43 m, 95%), and an attitude bound in each direction of 1.50 deg (0.51 deg, 95%). On local streets, the road geometry makes requirements more stringent where lateral and longitudinal error bounds of 0.29 m (0.10 m, 95%) are needed with an orientation requirement of 0.50 deg (0.17 deg, 95%).


Big-Data Clustering: K-Means or K-Indicators?

arXiv.org Machine Learning

The K-means algorithm is arguably the most popular data clustering method, commonly applied to processed datasets in some "feature spaces", as is in spectral clustering. Highly sensitive to initializations, however, K-means encounters a scalability bottleneck with respect to the number of clusters K as this number grows in big data applications. In this work, we promote a closely related model called K-indicators model and construct an efficient, semi-convex-relaxation algorithm that requires no randomized initializations. We present extensive empirical results to show advantages of the new algorithm when K is large. In particular, using the new algorithm to start the K-means algorithm, without any replication, can significantly outperform the standard K-means with a large number of currently state-of-the-art random replications.


Gated recurrent units viewed through the lens of continuous time dynamical systems

arXiv.org Machine Learning

Gated recurrent units (GRUs) are specialized memory elements for building recurrent neural networks. Despite their incredible success in natural language, speech, and video processing, little is understood about the specific dynamics representable in a GRU network, along with the constraints these dynamics impose when generalizing a specific task. As a result, it is difficult to know a priori how successful a GRU network will perform on a given task. Using a continuous time analysis, we gain intuition on the inner workings of GRU networks. We restrict our presentation to low dimensions to allow for a comprehensive visualization. We found a surprisingly rich repertoire of dynamical features that includes stable limit cycles (nonlinear oscillations), multi-stable dynamics with various topologies, and homoclinic orbits. We contextualize the usefulness of the different kinds of dynamics and experimentally test their existence.