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 Inductive Learning


Game-Based Video-Context Dialogue

arXiv.org Artificial Intelligence

Current dialogue systems focus more on textual and speech context knowledge and are usually based on two speakers. Some recent work has investigated static image-based dialogue. However, several real-world human interactions also involve dynamic visual context (similar to videos) as well as dialogue exchanges among multiple speakers. To move closer towards such multimodal conversational skills and visually-situated applications, we introduce a new video-context, many-speaker dialogue dataset based on live-broadcast soccer game videos and chats from Twitch.tv. This challenging testbed allows us to develop visually-grounded dialogue models that should generate relevant temporal and spatial event language from the live video, while also being relevant to the chat history. For strong baselines, we also present several discriminative and generative models, e.g., based on tridirectional attention flow (TriDAF). We evaluate these models via retrieval ranking-recall, automatic phrase-matching metrics, as well as human evaluation studies. We also present dataset analyses, model ablations, and visualizations to understand the contribution of different modalities and model components.


Google case set to examine if EU data rules extend...

Daily Mail - Science & tech

Google is fighting in Europe's top court today to tighten the scope of an EU privacy law that grants citizens the'right to be forgotten'. The rule allows people to demand Google remove search results that mention outdated or embarrassing information about them. This includes links to websites mentioning serious incidents - such as bankruptcy or criminal convictions - that may cause that person to be stigmatised. Google is battling with France's data privacy regulator over an order to extend the rule to remove search results worldwide upon request. The dispute pits data privacy concerns against the public's right to know, while also raising thorny questions about how to enforce differing legal jurisdictions when it comes to the borderless internet.


Google case set to examine if EU data rules extend globally

USATODAY - Tech Top Stories

Google employees reviewing the company appreciate the company's benefits and perks, which include free food and coffee made by baristas in every building. Other benefits include onsite gyms, free workout classes, and shuttles for free and easy commuting. Employees also appear confident in the company's leadership. Google CEO Sundar Pichai has a near-perfect 95% approval rating on Glassdoor. LONDON – Google is going to Europe's top court in its legal fight against an order requiring it to extend "right to be forgotten" rules to its search engines globally.


Google Case Set to Examine if EU Data Rules Extend Globally

U.S. News

Not all requests are waved through. In a related case that will also be heard Tuesday, the EU court will be asked to weigh in on a request by four people in France who want their search results to be purged of any information about their political beliefs and criminal records, without taking into account public interest. Google had rejected their request, which was ultimately referred to the ECJ.


Addressing the Fundamental Tension of PCGML with Discriminative Learning

arXiv.org Machine Learning

Abstract--Procedural content generation via machine learning (PCGML) is typically framed as the task of fitting a generative model to full-scale examples of a desired content distribution. This approach presents a fundamental tension: the more design effort expended to produce detailed training examples for shaping a generator, the lower the return on investment from applying PCGML in the first place. In response, we propose the use of discriminative models (which capture the validity of a design rather the distribution of the content) trained on positive and negative examples. Through a modest modification of WaveFunctionCollapse, a commercially-adopted PCG approach that we characterize as using elementary machine learning, we demonstrate a new mode of control for learning-based generators. We demonstrate how an artist might craft a focused set of additional positive and negative examples by critique of the generator's previous outputs. This interaction mode bridges PCGML with mixed-initiative design assistance tools by working with a machine to define a space of valid designs rather than just one new design. Procedural Content Generation via Machine Learning (PCGML) is the recent term for the strategy of controlling content generators using examples [1]. Existing PCGML approaches train their statistical models based on preexisting artist-provided samples of the desired content. However, there is a fundamental tension here: machine learning often works better with more training data, but the effort to produce quality training data is frequently costly enough that the artists might be better off just making the content themselves. Rather than attempting to train a generative statistical model (capturing the distribution of desired content), we focus on applying discriminative learning. In discriminative learning, the model learns to judge whether a candidate content artifact would be valid or desirable, but it does not learn how to generate candidates. Pairing a discriminative model with a preexisting content generator, we realize example-driven generation that can be influenced by both positive and negative examples of valid design patterns.


Sample Complexity of Nonparametric Semi-Supervised Learning

arXiv.org Machine Learning

We study the sample complexity of semi-supervised learning (SSL) and introduce new assumptions based on the mismatch between a mixture model learned from unlabeled data and the true mixture model induced by the (unknown) class conditional distributions. Under these assumptions, we establish an $\Omega(K\log K)$ labeled sample complexity bound without imposing parametric assumptions, where $K$ is the number of classes. Our results suggest that even in nonparametric settings it is possible to learn a near-optimal classifier using only a few labeled samples. Unlike previous theoretical work which focuses on binary classification, we consider general multiclass classification ($K>2$), which requires solving a difficult permutation learning problem. This permutation defines a classifier whose classification error is controlled by the Wasserstein distance between mixing measures, and we provide finite-sample results characterizing the behaviour of the excess risk of this classifier. Finally, we describe three algorithms for computing these estimators based on a connection to bipartite graph matching, and perform experiments to illustrate the superiority of the MLE over the majority vote estimator.


The Curse of Concentration in Robust Learning: Evasion and Poisoning Attacks from Concentration of Measure

arXiv.org Machine Learning

Many modern machine learning classifiers are shown to be vulnerable to adversarial perturbations of the instances that can "evade" the classifier and get misclassified. Despite a massive amount of work focusing on making classifiers robust, the task seems quite challenging. In this work, through a theoretical study, we investigate the adversarial risk and robustness of classifiers and draw a connection to the well-known phenomenon of "concentration of measure" in metric measure spaces. We show that if the metric probability space of the test instance is concentrated, any classifier with some initial constant error is inherently vulnerable to adversarial perturbations. One class of concentrated metric probability spaces are the so-called Levy families that include many natural distributions. In this special case, our attacks only need to perturb the test instance by at most $O(\sqrt n)$ to make it misclassified, where $n$ is the data dimension. Using our general result about Levy instance spaces, we first recover as special case some of the previously proved results about the existence of adversarial examples. However, many more Levy families are known for which we immediately obtain new attacks finding adversarial examples (e.g., product distribution under the Hamming distance). Finally, we show that concentration of measure for product spaces implies the existence of so called "poisoning" attacks in which the adversary tampers with the training data with the goal of increasing the error of the classifier. We show that for any deterministic learning algorithm that uses $m$ training examples, there is an adversary who substitutes $O(\sqrt m)$ of the examples with other (still correctly labeled) ones and can almost fully degrade the confidence parameter of any PAC learning algorithm or alternatively increase the risk to almost 1 if the adversary also knows the final test example.


Semi-supervised Learning on Graphs with Generative Adversarial Nets

arXiv.org Artificial Intelligence

We investigate how generative adversarial nets (GANs) can help semi-supervised learning on graphs. We first provide insights on working principles of adversarial learning over graphs and then present GraphSGAN, a novel approach to semi-supervised learning on graphs. In GraphSGAN, generator and classifier networks play a novel competitive game. At equilibrium, generator generates fake samples in low-density areas between subgraphs. In order to discriminate fake samples from the real, classifier implicitly takes the density property of subgraph into consideration. An efficient adversarial learning algorithm has been developed to improve traditional normalized graph Laplacian regularization with a theoretical guarantee. Experimental results on several different genres of datasets show that the proposed GraphSGAN significantly outperforms several state-of-the-art methods. GraphSGAN can be also trained using mini-batch, thus enjoys the scalability advantage.


Adaptation and Robust Learning of Probabilistic Movement Primitives

arXiv.org Machine Learning

These representations are able to capture the variability of the demonstrations from a teacher as a probability distribution over trajectories, providing a sensible region of exploration and the ability to adapt to changes in the robot environment. However, to be able to capture variability and correlations between different joints, a probabilistic movement primitive requires the estimation of a larger number of parameters compared to their deterministic counterparts, that focus on modeling only the mean behavior. In this paper, we make use of prior distributions over the parameters of a probabilistic movement primitive to make robust estimates of the parameters with few training instances. In addition, we introduce general purpose operators to adapt movement primitives in joint and task space. The proposed training method and adaptation operators are tested in a coffee preparation and in robot table tennis task. In the coffee preparation task we evaluate the generalization performance to changes in the location of the coffee grinder and brewing chamber in a target area, achieving the desired behavior after only two demonstrations. In the table tennis task we evaluate the hit and return rates, outperforming previous approaches while using fewer task specific heuristics.


Building a Robust Text Classifier on a Test-Time Budget

arXiv.org Machine Learning

In this paper, we study a generic learning framework for building robust text classification model that achieves accuracy comparable to standard full models under test-time budget constraints. Our approach learns a selector to identify words that are relevant to the prediction tasks and only passes these words to the classifier for processing. The selector is trained jointly with the classifier and directly learns to incorporate with the classifier. We further propose a data aggregation scheme to improve the robustness of the classifier. Our learning framework is general and can be incorporated with any type of text classification model. On real-world data, we show that the proposed approach improves the performance of a given classifier and speeds up the model with a mere loss in accuracy performance.