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 Unsupervised or Indirectly Supervised Learning


Simulated and Unsupervised Learning: Apple's New Approach to AI

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Earlier this month, Apple's Director of AI Research, Russ Salakhutdinov, announced that the company was getting into publishing research. The six researchers who published the paper belong to a recently formed machine learning group. Synthetic images and videos are being used to train machine learning models. They are readily available, less costly, and customizable. Although the new technique reportedly has a lot of potential, it is risky because generated images do not meet the same quality standards as real images.


A Non-generative Framework and Convex Relaxations for Unsupervised Learning

arXiv.org Machine Learning

We give a novel formal theoretical framework for unsupervised learning with two distinctive characteristics. First, it does not assume any generative model and based on a worst-case performance metric. Second, it is comparative, namely performance is measured with respect to a given hypothesis class. This allows to avoid known computational hardness results and improper algorithms based on convex relaxations. We show how several families of unsupervised learning models, which were previously only analyzed under probabilistic assumptions and are otherwise provably intractable, can be efficiently learned in our framework by convex optimization.


Highlights of NIPS 2016: Adversarial Learning, Meta-learning and more

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In second place, Ng saw neither unsupervised learning nor reinforcement learning, but transfer learning. One of the hottest developments within Deep Learning was Generative Adversarial Networks (GANs). Secondly, end-to-end (supervised) Deep Learning allows us to learn to map from inputs directly to outputs. The Conference on Neural Information Processing Systems (NIPS) is one of the two top conferences in machine learning. Among ML research areas, supervised learning is the undisputed driver of the recent success of ML and will likely continue to drive it for the foreseeable future.


Apple leaps into AI research with improved simulated unsupervised learning

#artificialintelligence

Corporate machine learning research may be getting a new vanguard in Apple. Six researchers from the company's recently formed machine learning group published a paper that describes a novel method for simulated unsupervised learning. The aim is to improve the quality of synthetic training images. The work is a sign of the company's aspirations to become a more visible leader in the ever growing field of AI. Google, Facebook, Microsoft and the rest of the techstablishment have been steadily growing their machine learning research groups.


Apple publishes its very first AI research paper

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Artificial intelligence (AI) and machine learning (ML) research communities have been critical of Apple's secretiveness to the point that it's hurt the firm's recruiting efforts and prompted it to change its tough stance against publicizing any internal AI findings. Last weekend, Apple finally published its very first AI paper, Forbes reported today. Submitted for publication on November 15, the document outlines a technique for improving the training of an algorithm's ability to recognize objects on images using computer-generated images rather than real-world ones. The paper explains that synthetic image data is often "not realistic enough", leading the network to learn details only present in synthetic images and fail to generalize well on real images. Simulated Unsupervised learning relies on a new machine learning technique, called Generative Adversarial Networks, that increases the realism of a simulated image by basically pitting two neural networks against each other.


RSSL: Semi-supervised Learning in R

arXiv.org Machine Learning

In this paper, we introduce a package for semi-supervised learning research in the R programming language called RSSL. We cover the purpose of the package, the methods it includes and comment on their use and implementation. We then show, using several code examples, how the package can be used to replicate well-known results from the semi-supervised learning literature.


3D Generative Adversarial Network

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We study the problem of 3D object generation. We propose a novel framework, namely 3D Generative Adversarial Network (3D-GAN), which generates 3D objects from a probabilistic space by leveraging recent advances in volumetric convolutional networks and generative adversarial nets. The benefits of our model are three-fold: first, the use of an adversarial criterion, instead of traditional heuristic criteria, enables the generator to capture object structure implicitly and to synthesize high-quality 3D objects; second, the generator establishes a mapping from a low-dimensional probabilistic space to the space of 3D objects, so that we can sample objects without a reference image or CAD models, and explore the 3D object manifold; third, the adversarial discriminator provides a powerful 3D shape descriptor which, learned without supervision, has wide applications in 3D object recognition. Experiments demonstrate that our method generates high-quality 3D objects, and our unsupervisedly learned features achieve impressive performance on 3D object recognition, comparable with those of supervised learning methods.


Causal Discovery as Semi-Supervised Learning

arXiv.org Machine Learning

In this short report, we discuss an approach to estimating causal graphs in which indicators of causal influence between variables are treated as labels in a machine learning formulation. Available data on the variables of interest are used as "inputs" to estimate the labels. We frame the problem as one of semi-supervised learning: available interventional data or background knowledge provide labels on some edges in the graph and the remaining edges are treated as unlabelled objects. To illustrate the key ideas, we consider a simple approach to feature construction (rooted in bivariate kernel density estimation) and embed this within a semi-supervised manifold framework. Results on yeast knockout data demonstrate that the proposed approach can identify causal relationships as validated by unseen interventional experiments. An advantage of the formulation we propose is that by reframing causal discovery as semi-supervised learning, it allows a range of data-driven approaches to be brought to bear on causal discovery, without demanding specification of full probability models or explicit models of underlying mechanisms.


Graph-based semi-supervised learning for relational networks

arXiv.org Machine Learning

We address the problem of semi-supervised learning in relational networks, networks in which nodes are entities and links are the relationships or interactions between them. Typically this problem is confounded with the problem of graph-based semi-supervised learning (GSSL), because both problems represent the data as a graph and predict the missing class labels of nodes. However, not all graphs are created equally. In GSSL a graph is constructed, often from independent data, based on similarity. As such, edges tend to connect instances with the same class label. Relational networks, however, can be more heterogeneous and edges do not always indicate similarity. For instance, instead of links being more likely to connect nodes with the same class label, they may occur more frequently between nodes with different class labels (link-heterogeneity). Or nodes with the same class label do not necessarily have the same type of connectivity across the whole network (class-heterogeneity), e.g. in a network of sexual interactions we may observe links between opposite genders in some parts of the graph and links between the same genders in others. Performing classification in networks with different types of heterogeneity is a hard problem that is made harder still when we do not know a-priori the type or level of heterogeneity. Here we present two scalable approaches for graph-based semi-supervised learning for the more general case of relational networks. We demonstrate these approaches on synthetic and real-world networks that display different link patterns within and between classes. Compared to state-of-the-art approaches, ours give better classification performance without prior knowledge of how classes interact. In particular, our two-step label propagation algorithm gives consistently good accuracy and runs on networks of over 1.6 million nodes and 30 million edges in around 12 seconds.


Generalizable Features From Unsupervised Learning

arXiv.org Machine Learning

Humans learn a predictive model of the world and use this model to reason about future events and the consequences of actions. In contrast to most machine predictors, we exhibit an impressive ability to generalize to unseen scenarios and reason intelligently in these settings. One important aspect of this ability is physical intuition (Lake et al., 2016). In this work, we explore the potential of unsupervised learning to find features that promote better generalization to settings outside the supervised training distribution. Our task is predicting the stability of towers of square blocks. We demonstrate that an unsupervised model, trained to predict future frames of a video sequence of stable and unstable block configurations, can yield features that support extrapolating stability prediction to blocks configurations outside the training set distribution.