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 Statistical Learning


Learned Uncertainty-Aware (LUNA) Bases for Bayesian Regression using Multi-Headed Auxiliary Networks

arXiv.org Machine Learning

Neural Linear Models (NLM) are deep models that produce predictive uncertainty by learning features from the data and then performing Bayesian linear regression over these features. Despite their popularity, few works have focused on formally evaluating the predictive uncertainties of these models. In this work, we show that traditional training procedures for NLMs can drastically underestimate uncertainty in data-scarce regions. We identify the underlying reasons for this behavior and propose a novel training procedure for capturing useful predictive uncertainties.


Use Cases for Machine Learning on VMware Cloud on AWS – Part 1 - VMware Cloud Community

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It's easy for your business to get started with ML by analyzing tabular data using existing CPU-based VMs – no specialized hardware required. We explore a range of applications for ML using VMware Cloud on AWS that can deliver immediate value. This series of blog articles presents different use cases for deploying machine learning algorithms and applications on VMware Cloud on AWS and other VMware Cloud infrastructure. At the time of writing, June 2020, the hardware accelerators for neural networks are not yet available on VMware Cloud on AWS. However, there are many very good reasons to deploy classic machine learning algorithms that perform well on CPU-based VMs onto VMware Cloud on AWS. We describe these use-cases in this and the following articles.


Scratch Neural Network from in TensorFlow

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Neural Network from Scratch in TensorFlow Create a predict function. Create the main training mechanism and implement gradient descent with automatic differentiation. Apply the neural network model to solve a multi-class classification problem. How to implement a neural network from scratch using TensorFlow. How to solve a multi-class classification problem using the neural network implementation.


Top 51 Data Science Interview Questions! - Simpliv Blog

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Data Science is one of the most dynamic fields in technology attracting innumerable candidates towards it. However, not everyone ends up landing on a good Data Scientist profile. With the cut-throat competition among the candidates, you need to have the edge to have an upper hand. Therefore, it is very much important for the aspirants to know those common and tricky questions that are asked by the interviews. Before going through the Interview question, it is suggested that you get you acquire the fundamental knowledge of Data Science.


How to Use Feature Extraction on Tabular Data for Machine Learning

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Machine learning predictive modeling performance is only as good as your data, and your data is only as good as the way you prepare it for modeling. The most common approach to data preparation is to study a dataset and review the expectations of a machine learning algorithm, then carefully choose the most appropriate data preparation techniques to transform the raw data to best meet the expectations of the algorithm. This is slow, expensive, and requires a vast amount of expertise. An alternative approach to data preparation is to apply a suite of common and commonly useful data preparation techniques to the raw data in parallel and combine the results of all of the transforms together into a single large dataset from which a model can be fit and evaluated. This is an alternative philosophy for data preparation that treats data transforms as an approach to extract salient features from raw data to expose the structure of the problem to the learning algorithms.


How to Use Feature Extraction on Tabular Data for Machine Learning - AnalyticsWeek

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Machine learning predictive modeling performance is only as good as your data, and your data is only as good as the way you prepare it for modeling. The most common approach to data preparation is to study a dataset and review the expectations of a machine learning algorithm, then carefully choose the most appropriate data preparation techniques to transform the raw data to best meet the expectations of the algorithm. This is slow, expensive, and requires a vast amount of expertise. An alternative approach to data preparation is to apply a suite of common and commonly useful data preparation techniques to the raw data in parallel and combine the results of all of the transforms together into a single large dataset from which a model can be fit and evaluated. This is an alternative philosophy for data preparation that treats data transforms as an approach to extract salient features from raw data to expose the structure of the problem to the learning algorithms.


Machine Learning Case Study

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We are living in the era of digital technologies. When was the last time you walked into a shop that didn't have a PayTM or BHIM UPI? These digital transaction technologies have quickly become a key part of our daily lives. And not just at an individual level, these digital technologies are at the core of every financial institution. Executing a payment transaction or fund transfer has become very smooth with multiple possible options (like internet banking, ATM, credit or debit cards, UPI, POS Machines, etc.) having reliable systems running at the backend.


Bypassing the Ambient Dimension: Private SGD with Gradient Subspace Identification

arXiv.org Machine Learning

Differentially private SGD (DP-SGD) is one of the most popular methods for solving differentially private empirical risk minimization (ERM). Due to its noisy perturbation on each gradient update, the error rate of DP-SGD scales with the ambient dimension $p$, the number of parameters in the model. Such dependence can be problematic for over-parameterized models where $p \gg n$, the number of training samples. Existing lower bounds on private ERM show that such dependence on $p$ is inevitable in the worst case. In this paper, we circumvent the dependence on the ambient dimension by leveraging a low-dimensional structure of gradient space in deep networks---that is, the stochastic gradients for deep nets usually stay in a low dimensional subspace in the training process. We propose Projected DP-SGD that performs noise reduction by projecting the noisy gradients to a low-dimensional subspace, which is given by the top gradient eigenspace on a small public dataset. We provide a general sample complexity analysis on the public dataset for the gradient subspace identification problem and demonstrate that under certain low-dimensional assumptions the public sample complexity only grows logarithmically in $p$. Finally, we provide a theoretical analysis and empirical evaluations to show that our method can substantially improve the accuracy of DP-SGD.


Improving Interpretability of CNN Models Using Non-Negative Concept Activation Vectors

arXiv.org Artificial Intelligence

Convolutional neural network (CNN) models for computer vision are powerful but lack explainability in their most basic form. This deficiency remains a key challenge when applying CNNs in important domains. Recent work for explanations through feature importance of approximate linear models has moved from input-level features (pixels or segments) to features from mid-layer feature maps in the guise of concept activation vectors (CAVs). CAVs contain concept-level information and could be learnt via Clustering. In this work, we rethink the ACE algorithm of Ghorbani et~al., proposing an alternative concept-based explanation framework. Based on the requirements of fidelity (approximate models) and interpretability (being meaningful to people), we design measurements and evaluate a range of dimensionality reduction methods for alignment with our framework. We find that non-negative concept activation vectors from non-negative matrix factorization provide superior performance in interpretability and fidelity based on computational and human subject experiments. Our framework provides both local and global concept-level explanations for pre-trained CNN models.


On the Generalization Effects of Linear Transformations in Data Augmentation

arXiv.org Artificial Intelligence

Data augmentation is a powerful technique to improve performance in applications such as image and text classification tasks. Yet, there is little rigorous understanding of why and how various augmentations work. In this work, we consider a family of linear transformations and study their effects on the ridge estimator in an over-parametrized linear regression setting. First, we show that transformations which preserve the labels of the data can improve estimation by enlarging the span of the training data. Second, we show that transformations which mix data can improve estimation by playing a regularization effect. Finally, we validate our theoretical insights on MNIST. Based on the insights, we propose an augmentation scheme that searches over the space of transformations by how uncertain the model is about the transformed data. We validate our proposed scheme on image and text datasets. For example, our method outperforms RandAugment by 1.24% on CIFAR-100 using Wide-ResNet-28-10. Furthermore, we achieve comparable accuracy to the SoTA Adversarial AutoAugment on CIFAR datasets.