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Excess risk bounds in robust empirical risk minimization
Minsker, Stanislav, Mathieu, Timothée
A recent Forbes article [41] states that "Machine learning algorithms are very dependent on accurate, clean, and well-labeled training data to learn from so that they can produce accurate results" and "According to a recent report from AI research and advisory firm Cognilytica, over 80% of the time spent in AI projects are spent dealing with and wrangling data." While some abnormal samples, or outliers, can be detected and filtered during the preprocessing steps, others are more difficult to detect: for instance, a sophisticated adversary might try to "poison" data to force a desired outcome [33]. Other seemingly abnormal observations could be inherent to the underlying data-generating process. An "ideal" learning method should not discard informative samples, while limiting the effect of individual observation on the output of the learning algorithm at the same time. We are interested in robust methods that are model-free, and require minimal assumptions on the underlying distribution. We study two types of robustness: robustness to heavy tails expressed in terms of the moment requirements, as well as robustness to adversarial contamination. Heavy tails can be used to model variation and randomness naturally occurring in the sample, while adversarial contamination is a convenient way to model outliers of unknown nature. The statistical framework used throughout the paper is defined as follows. Let p S, S q be a measurable space, and let X P S be a random variable with distribution P .
Audio-Conditioned U-Net for Position Estimation in Full Sheet Images
Henkel, Florian, Kelz, Rainer, Widmer, Gerhard
The goal of score following is to track a musical performance, usually in the form of audio, in a corresponding score representation. Established methods mainly rely on computer-readable scores in the form of MIDI or MusicXML and achieve robust and reliable tracking results. Recently, multimodal deep learning methods have been used to follow along musical performances in raw sheet images. Among the current limits of these systems is that they require a non trivial amount of preprocessing steps that unravel the raw sheet image into a single long system of staves. The current work is an attempt at removing this particular limitation. We propose an architecture capable of estimating matching score positions directly within entire unprocessed sheet images. We argue that this is a necessary first step towards a fully integrated score following system that does not rely on any preprocessing steps such as optical music recognition.
Rugby-Bot: Utilizing Multi-Task Learning & Fine-Grained Features for Rugby League Analysis
Holbrook, Matthew, Hobbs, Jennifer, Lucey, Patrick
Sporting events are extremely complex and require a multitude of metrics to accurate describe the event. When making multiple predictions, one should make them from a single source to keep consistency across the predictions. We present a multi-task learning method of generating multiple predictions for analysis via a single prediction source. To enable this approach, we utilize a fine-grain representation using fine-grain spatial data using a wide-and-deep learning approach. Additionally, our approach can predict distributions rather than single point values. We highlighted the utility of our approach on the sport of Rugby League and call our prediction engine "Rugby-Bot".
Transform the Set: Memory Attentive Generation of Guided and Unguided Image Collages
Jetchev, Nikolay, Bergmann, Urs, Yildirim, Gökhan
Cutting and pasting image segments feels intuitive: the choice of source templates gives artists flexibility in recombining existing source material. Formally, this process takes an image set as input and outputs a collage of the set elements. Such selection from sets of source templates does not fit easily in classical convolutional neural models requiring inputs of fixed size. Inspired by advances in attention and set-input machine learning, we present a novel architecture that can generate in one forward pass image collages of source templates using set-structured representations. This paper has the following contributions: (i) a novel framework for image generation called Memory Attentive Generation of Image Collages (MAGIC) which gives artists new ways to create digital collages; (ii) from the machine-learning perspective, we show a novel Generative Adversarial Networks (GAN) architecture that uses Set-Transformer layers and set-pooling to blend sets of random image samples - a hybrid non-parametric approach.
MLQA: Evaluating Cross-lingual Extractive Question Answering
Lewis, Patrick, Oğuz, Barlas, Rinott, Ruty, Riedel, Sebastian, Schwenk, Holger
Question answering (QA) models have shown rapid progress enabled by the availability of large, high-quality benchmark datasets. Such annotated datasets are difficult and costly to collect, and rarely exist in languages other than English, making training QA systems in other languages challenging. An alternative to building large monolingual training datasets is to develop cross-lingual systems which can transfer to a target language without requiring training data in that language. In order to develop such systems, it is crucial to invest in high quality multilingual evaluation benchmarks to measure progress. We present MLQA, a multi-way aligned extractive QA evaluation benchmark intended to spur research in this area. MLQA contains QA instances in 7 languages, namely English, Arabic, German, Spanish, Hindi, Vietnamese and Simplified Chinese. It consists of over 12K QA instances in English and 5K in each other language, with each QA instance being parallel between 4 languages on average. MLQA is built using a novel alignment context strategy on Wikipedia articles, and serves as a cross-lingual extension to existing extractive QA datasets. We evaluate current state-of-the-art cross-lingual representations on MLQA, and also provide machine-translation-based baselines. In all cases, transfer results are shown to be significantly behind training-language performance.
Universal Marginaliser for Deep Amortised Inference for Probabilistic Programs
Walecki, Robert, Gourgoulias, Kostis, Baker, Adam, Hart, Chris, Lucas, Chris, Zwiessele, Max, Buchard, Albert, Lomeli, Maria, Perov, Yura, Johri, Saurabh
Probabilistic programming languages (PPLs) are powerful modelling tools which allow to formalise our knowledge about the world and reason about its inherent uncertainty. Inference methods used in PPL can be computationally costly due to significant time burden and/or storage requirements; or they can lack theoretical guarantees of convergence and accuracy when applied to large scale graphical models. To this end, we present the Universal Marginaliser (UM), a novel method for amortised inference, in PPL. We show how combining samples drawn from the original probabilistic program prior with an appropriate augmentation method allows us to train one neural network to approximate any of the corresponding conditional marginal distributions, with any separation into latent and observed variables, and thus amortise the cost of inference. Finally, we benchmark the method on multiple probabilistic programs, in Pyro, with different model structure.
On Learning Paradigms for the Travelling Salesman Problem
Joshi, Chaitanya K., Laurent, Thomas, Bresson, Xavier
We explore the impact of learning paradigms on training deep neural networks for the Travelling Salesman Problem. We design controlled experiments to train supervised learning (SL) and reinforcement learning (RL) models on fixed graph sizes up to 100 nodes, and evaluate them on variable sized graphs up to 500 nodes. Beyond not needing labelled data, out results reveal favorable properties of RL over SL: RL training leads to better emergent generalization to variable graph sizes and is a key component for learning scale-invariant solvers for novel combinatorial problems.
Label-Conditioned Next-Frame Video Generation with Neural Flows
--Recent state-of-the-art video generation systems employ Generative Adversarial Networks (GANs) or V ariational Autoencoders (V AEs) to produce novel videos. However, V AE models typically produce blurry outputs when faced with sub-optimal conditioning of the input, and GANs are known to be unstable for large output sizes. In addition, the output videos of these models are difficult to evaluate, partly because the GAN loss function is not an accurate measure of convergence. In this work, we propose using a state-of-the-art neural flow generator called Glow to generate videos conditioned on a textual label, one frame at a time. Neural flow models are more stable than standard GANs, as they only optimize a single cross entropy loss function, which is monotonic and avoids the circular convergence issues of the GAN minimax objective. In addition, we also show how to condition Glow on external context, while still preserving the invertible nature of each "flow" layer . Finally, we evaluate the proposed Glow model by calculating cross entropy on a held-out validation set of videos, in order to compare multiple versions of the proposed model via an ablation study. We show generated videos and discuss future improvements. I NTRODUCTION Text-to-video generation is the process by which a model conditions on text, and produces a video based on that text description. This is the exact opposite of video captioning, which aims to produce a caption that would describe a given video [6]. It may be argued that text-to-video is a harder task, as there are many more degrees of freedom in pixel space.
Adaptive and Iteratively Improving Recurrent Lateral Connections
Adaptive and Iteratively Improving Recurrent Lateral ConnectionsBarak Battash Lior Wolf Tel Aviv University Facebook AI Research & Tel Aviv University Abstract The current leading computer vision models are typically feed forward neural models, in which the output of one computational block is passed to the next one sequentially. This is in sharp contrast to the organization of the primate visual cortex, in which feedback and lateral connections are abundant. In this work, we propose a computational model for the role of lateral connections in a given block, in which the weights of the block vary dynamically as a function of its activations, and the input from the upstream blocks is iteratively reintroduced. We demonstrate how this novel architectural modification can lead to sizable gains in performance, when applied to visual action recognition without pretraining and that it outperforms the literature architectures with recurrent feedback processing on ImageNet. 1 Introduction Rapid exposure experiments in primates teach us that image recognition occurs as early as the first 100 msec of visual perception, a time budget that suffices only for feed-forward inference, due to the relatively slow nature of biological neurons (Perrett and Oram, 1993; Thorpe et al., 1996). However, anatomical studies have shown that feedback connections are prevalent in the cortex (Douglas and Martin, 2004; Felleman and Essen, 1991). As one striking example, the feedforward input from LGN to V1 in cats constitutes only five percent of the total input to V1, the rest being lateral and feedback connections (Binzegger et al., 2004). In fact, lateral connections, which are projections from a layer to itself, are even more prevalent than feedback connections that project from downstream layers upstream. One possible conjecture would be that feedback (including lateral) connections play roles that are replaced by other mechanisms in the current deep learning literature. For example, they could play a role in training the biological neural network, or they can form attention mechanisms, which are captured by attention (Sermanet et al., 2014) and self-attention (Parikh et al., 2016) blocks in modern neural networks. Similarly, one can claim that such connections are required due to the limitations of the biological computational, but may not be necessary in artificial neural networks, which can be extremely deep (Liao and Poggio, 2016).
Exploiting video sequences for unsupervised disentangling in generative adversarial networks
Tuesca, Facundo, Uzal, Lucas C.
In this work we present an adversarial training algorithm that exploits correlations in video to learn --without supervision-- an image generator model with a disentangled latent space. The proposed methodology requires only a few modifications to the standard algorithm of Generative Adversarial Networks (GAN) and involves training with sets of frames taken from short videos. We train our model over two datasets of face-centered videos which present different people speaking or moving the head: VidTIMIT and YouTube Faces datasets. We found that our proposal allows us to split the generator latent space into two subspaces. One of them controls content attributes, those that do not change along short video sequences. For the considered datasets, this is the identity of the generated face. The other subspace controls motion attributes, those attributes that are observed to change along short videos. We observed that these motion attributes are face expressions, head orientation, lips and eyes movement. The presented experiments provide quantitative and qualitative evidence supporting that the proposed methodology induces a disentangling of this two kinds of attributes in the latent space.