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 Statistical Learning


Embedded Ensembles: Infinite Width Limit and Operating Regimes

arXiv.org Machine Learning

A memory efficient approach to ensembling neural networks is to share most weights among the ensembled models by means of a single reference network. We refer to this strategy as Embedded Ensembling (EE); its particular examples are BatchEnsembles and Monte-Carlo dropout ensembles. In this paper we perform a systematic theoretical and empirical analysis of embedded ensembles with different number of models. Theoretically, we use a Neural-Tangent-Kernel-based approach to derive the wide network limit of the gradient descent dynamics. In this limit, we identify two ensemble regimes - independent and collective - depending on the architecture and initialization strategy of ensemble models. We prove that in the independent regime the embedded ensemble behaves as an ensemble of independent models. We confirm our theoretical prediction with a wide range of experiments with finite networks, and further study empirically various effects such as transition between the two regimes, scaling of ensemble performance with the network width and number of models, and dependence of performance on a number of architecture and hyperparameter choices.


An Information-theoretical Approach to Semi-supervised Learning under Covariate-shift

arXiv.org Machine Learning

A common assumption in semi-supervised learning is that the labeled, unlabeled, and test data are drawn from the same distribution. However, this assumption is not satisfied in many applications. In many scenarios, the data is collected sequentially (e.g., healthcare) and the distribution of the data may change over time often exhibiting so-called covariate shifts. In this paper, we propose an approach for semi-supervised learning algorithms that is capable of addressing this issue. Our framework also recovers some popular methods, including entropy minimization and pseudo-labeling. We provide new information-theoretical based generalization error upper bounds inspired by our novel framework. Our bounds are applicable to both general semi-supervised learning and the covariate-shift scenario. Finally, we show numerically that our method outperforms previous approaches proposed for semi-supervised learning under the covariate shift.


Sparse Neural Additive Model: Interpretable Deep Learning with Feature Selection via Group Sparsity

arXiv.org Machine Learning

Interpretable machine learning has demonstrated impressive performance while preserving explainability. In particular, neural additive models (NAM) offer the interpretability to the black-box deep learning and achieve state-of-the-art accuracy among the large family of generalized additive models. In order to empower NAM with feature selection and improve the generalization, we propose the sparse neural additive models (SNAM) that employ the group sparsity regularization (e.g. Group LASSO), where each feature is learned by a sub-network whose trainable parameters are clustered as a group. We study the theoretical properties for SNAM with novel techniques to tackle the non-parametric truth, thus extending from classical sparse linear models such as the LASSO, which only works on the parametric truth. Specifically, we show that SNAM with subgradient and proximal gradient descents provably converges to zero training loss as $t\to\infty$, and that the estimation error of SNAM vanishes asymptotically as $n\to\infty$. We also prove that SNAM, similar to LASSO, can have exact support recovery, i.e. perfect feature selection, with appropriate regularization. Moreover, we show that the SNAM can generalize well and preserve the `identifiability', recovering each feature's effect. We validate our theories via extensive experiments and further testify to the good accuracy and efficiency of SNAM.


Introduction to Linear Regression

#artificialintelligence

Linear regression attempts to model the relationship between two variables by fitting a linear equation to observed data. If this observed data is from the complete population, then the regression is a population regression. For this case, the determined values of the coefficients are exactly those describing the regression model for the given population. However, if the data is only a sample, then it's called sample regression. The determined values of the regression coefficients describe a regression model that is more or less "representative" for the population is thus provides just a more or less uncertain estimate.


Top 6 Machine Learning Algorithms for Classification

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The easiest way to distinguish a supervised learning and unsupervised learning is to see whether the data is labelled or not. Supervised learning learns a function to make prediction of a defined label based on the input data. It can be either classifying data into a category (classification problem) or forecasting an outcome (regression algorithms). Reinforcement learning is another type of machine learning, where the agents learn to take actions based on its interaction with the environment, with the aim to maximize rewards. It is most similar to the learning process of human, following a trial-and-error approach.


Multivariate Analysis using SAS

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As a first method, it gives you a good idea about the level of multicollinearity involved and how much the two specified sets relate to themselves and each other. Do not forget -- CCA is mainly used for prediction, not interpretation. And the last of the trio is the Discriminant Function Analysis (DFA) which is used to answer the question: Can a combination of variables be used to predict group membership? Because, if a set of variables predicts group membership, it is also connected to that group. DFA is a dimension-reduction technique related to Principal Component Analysis (PCA) and Canonical Correlation Analysis (CCA).


How to Become A Data Scientist - The perfect road map - TechVidvan

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You must be wondering how to become a Data Scientist? What skills are required to become a Data Scientist? I know so many questions will be there in your mind. With this article, you will find all the answers. But first, let's talk about the scope of Data Scientist in today's world.


Blog: Top 9 Machine Learning Algorithms to Use for SEO & Marketing

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A list of top machine learning algorithms for marketers that can help to understand trends in user behavior, which further assist with SEO and marketing-based decisions on big data. The way to advertise and manage your SEO is changing. The tools of the trade for marketers, product managers, and SMBS are ever-evolving. This next wave of MarTech has been ramping up and might put some of us out of business. We should keep an eye on the cutting-edge machine learning in marketing and SEO and neural network (AI) technologies being used to make our market assessments more accurate, campaigns more successful, and our customers ultimately more satisfied.


Backpropagation and Gradient Descent

#artificialintelligence

Backpropagation and gradient descent are two different methods that form a powerful combination in the learning process of neural networks. Let's try to understand the intuition of how this works. Neural networks learn through forward propagation, by using weights, biases, and nonlinear activation functions to calculate a prediction y from the input x that should match the true output y as closely as possible. There are several different loss functions and which one you choose depends on the type of machine learning problem you are facing. The goal of backpropagation is to adjust the weights and biases throughout the neural network based on the calculated cost so that the cost will be lower in the next iteration.


Flow-based sampling in the lattice Schwinger model at criticality

arXiv.org Artificial Intelligence

Institut für Theoretische Physik, Universität Heidelberg, Philosophenweg 16, 69120 Heidelberg, Germany Recent results suggest that flow-based algorithms may provide efficient sampling of field distributions for lattice field theory applications, such as studies of quantum chromodynamics and the Schwinger model. In this work, we provide a numerical demonstration of robust flow-based sampling in the Schwinger model at the critical value of the fermion mass. In contrast, at the same parameters, conventional methods fail to sample all parts of configuration space, leading to severely underestimated uncertainties. Many important physical systems across particle and condensed matter physics can be described in the language of quantum field theory (QFT). Autocorrelations may become especially severe if MCMC updates are configurations, which generates samples by continuously unlikely to generate transitions between modes that are evolving the fields through configuration space via Hamiltonian separated in configuration space.