Statistical Learning
Understanding Why Neural Networks Generalize Well Through GSNR of Parameters
Liu, Jinlong, Jiang, Guoqing, Bai, Yunzhi, Chen, Ting, Wang, Huayan
GSNR of a parameter is defined as the ratio between its gradient's squared mean and Previous work (Zhang et al., 2016; Hardt et al., 2015; Dziugaite & Roy, 2017) suggests that the The GSNR of a parameter is defined as the ratio between its gradient's squared mean and variance Previous work tried to use GSNR to conduct theoretical analysis on deep learning. For example, Rainforth et al. (2018) used GSNR to analyze variational bounds in Intuitively, GSNR measures the similarity of a parameter's gradients among different training samples. To reveal the mechanism of DNNs' good generalization ability, we show that the gradient descent We believe this is probably the key to DNNs' remarkable generalization ability. In the remainder of this paper we first analyze the relation between GSNR and generalization (Section 2). At a particular point of the parameter space, GSNR measures the consistency of a parameter's gradients across different data samples.
ShapeVis: High-dimensional Data Visualization at Scale
Kumari, Nupur, R., Siddarth, Rupela, Akash, Gupta, Piyush, Krishnamurthy, Balaji
We present ShapeVis, a scalable visualization technique for point cloud data inspired from topological data analysis. Our method captures the underlying geometric and topological structure of the data in a compressed graphical representation. Much success has been reported by the data visualization technique Mapper, that discreetly approximates the Reeb graph of a filter function on the data. However, when using standard dimensionality reduction algorithms as the filter function, Mapper suffers from considerable computational cost. This makes it difficult to scale to high-dimensional data. Our proposed technique relies on finding a subset of points called landmarks along the data manifold to construct a weighted witness-graph over it. This graph captures the structural characteristics of the point cloud, and its weights are determined using a Finite Markov Chain. We further compress this graph by applying induced maps from standard community detection algorithms. Using techniques borrowed from manifold tearing, we prune and reinstate edges in the induced graph based on their modularity to summarize the shape of data. We empirically demonstrate how our technique captures the structural characteristics of real and synthetic data sets. Further, we compare our approach with Mapper using various filter functions like t-SNE, UMAP, LargeVis and show that our algorithm scales to millions of data points while preserving the quality of data visualization.
Artificial Intelligence for Digital Agriculture at Scale: Techniques, Policies, and Challenges
Chaterji, Somali, DeLay, Nathan, Evans, John, Mosier, Nathan, Engel, Bernard, Buckmaster, Dennis, Chandra, Ranveer
Digital agriculture has the promise to transform agricultural throughput. It can do this by applying data science and engineering for mapping input factors to crop throughput, while bounding the available resources. In addition, as the data volumes and varieties increase with the increase in sensor deployment in agricultural fields, data engineering techniques will also be instrumental in collection of distributed data as well as distributed processing of the data. These have to be done such that the latency requirements of the end users and applications are satisfied. Understanding how farm technology and big data can improve farm productivity can significantly increase the world's food production by 2050 in the face of constrained arable land and with the water levels receding. While much has been written about digital agriculture's potential, little is known about the economic costs and benefits of these emergent systems. In particular, the on-farm decision making processes, both in terms of adoption and optimal implementation, have not been adequately addressed. For example, if some algorithm needs data from multiple data owners to be pooled together, that raises the question of data ownership. This paper is the first one to bring together the important questions that will guide the end-to-end pipeline for the evolution of a new generation of digital agricultural solutions, driving the next revolution in agriculture and sustainability under one umbrella.
Algorithmic Fairness
An increasing number of decisions regarding the daily lives of human beings are being controlled by artificial intelligence (AI) algorithms in spheres ranging from healthcare, transportation, and education to college admissions, recruitment, provision of loans and many more realms. Since they now touch on many aspects of our lives, it is crucial to develop AI algorithms that are not only accurate but also objective and fair. Recent studies have shown that algorithmic decision-making may be inherently prone to unfairness, even when there is no intention for it. This paper presents an overview of the main concepts of identifying, measuring and improving algorithmic fairness when using AI algorithms. The paper begins by discussing the causes of algorithmic bias and unfairness and the common definitions and measures for fairness. Fairness-enhancing mechanisms are then reviewed and divided into pre-process, in-process and post-process mechanisms. A comprehensive comparison of the mechanisms is then conducted, towards a better understanding of which mechanisms should be used in different scenarios. The paper then describes the most commonly used fairness-related datasets in this field. Finally, the paper ends by reviewing several emerging research sub-fields of algorithmic fairness.
Combining Federated and Active Learning for Communication-efficient Distributed Failure Prediction in Aeronautics
Aussel, Nicolas, Chabridon, Sophie, Petetin, Yohan
--Machine Learning has proven useful in the recent years as a way to achieve failure prediction for industrial systems. However, the high computational resources necessary to run learning algorithms are an obstacle to its widespread application. The sub-field of Distributed Learning offers a solution to this problem by enabling the use of remote resources but at the expense of introducing communication costs in the application that are not always acceptable. In this paper, we propose a distributed learning approach able to optimize the use of computational and communication resources to achieve excellent learning model performances through a centralized architecture. T o achieve this, we present a new centralized distributed learning algorithm that relies on the learning paradigms of Active Learning and Federated Learning to offer a communication-efficient method that offers guarantees of model precision on both the clients and the central server . We evaluate this method on a public benchmark and show that its performances in terms of precision are very close to state-of-the-art performance level of non-distributed learning despite additional constraints. A. General problem In the recent years, the efficiency of Machine Learning for automated processing of large volumes of data has been widely demonstrated. This has been of particular interest for industrial applications that commonly generate large datasets.
Undersampling Algorithms for Imbalanced Classification
Taken from Improving Identification of Difficult Small Classes by Balancing Class Distribution. This technique can be implemented using the NeighbourhoodCleaningRule imbalanced-learn class. The number of neighbors used in the ENN and CNN steps can be specified via the n_neighbors argument that defaults to three. The threshold_cleaning controls whether or not the CNN is applied to a given class, which might be useful if there are multiple minority classes with similar sizes. This is kept at 0.5.
Customer Analytics in Python 2020
Customer Analytics in Python 2020 Get udemy course coupon code Customer Analytics in Python – the place where marketing and data science meet! What will you learn in this course? We will introduce you to the relevant theory that you need to start performing customer analytics. Then we will perform cluster analysis and dimensionality reduction to help you segment your customers. What you'll learn Master beginner and advanced customer analytics Learn the most important type of analysis applied by mid and large companies Gain access to a professional team of trainers with exceptional quant skills Wow interviewers by acquiring a highly desired skill Understand the fundamental marketing modeling theory: segmentation, targeting, positioning, marketing mix, and price elasticity; Apply segmentation on your customers, starting from raw data and reaching final customer segments; Perform K-means clustering with a customer analytics focus; Apply Principal Components Analysis (PCA) on your data to preprocess your features; Combine PCA and K-means for even more professional customer segmentation; Deploy your models on a different dataset; Learn how to model purchase incidence through probability of purchase elasticity; Model brand choice by exploring own-price and cross-price elasticity; Complete the purchasing cycle by predicting purchase quantity elasticity Carry out a black box deep learning model with TensorFlow 2.0 to predict purchasing behavior with unparalleled accuracy Be able to optimize your neural networks to enhance results Description Data science and Marketing are two of the key driving forces that help companies create value and stay on top in today's fast-paced economy.
Intelligence, physics and information -- the tradeoff between accuracy and simplicity in machine learning
How can we enable machines to make sense of the world, and become better at learning? To approach this goal, I believe viewing intelligence in terms of many integral aspects, and also a universal two-term tradeoff between task performance and complexity, provides two feasible perspectives. In this thesis, I address several key questions in some aspects of intelligence, and study the phase transitions in the two-term tradeoff, using strategies and tools from physics and information. Firstly, how can we make the learning models more flexible and efficient, so that agents can learn quickly with fewer examples? Inspired by how physicists model the world, we introduce a paradigm and an AI Physicist agent for simultaneously learning many small specialized models (theories) and the domain they are accurate, which can then be simplified, unified and stored, facilitating few-shot learning in a continual way. Secondly, for representation learning, when can we learn a good representation, and how does learning depend on the structure of the dataset? We approach this question by studying phase transitions when tuning the tradeoff hyperparameter. In the information bottleneck, we theoretically show that these phase transitions are predictable and reveal structure in the relationships between the data, the model, the learned representation and the loss landscape. Thirdly, how can agents discover causality from observations? We address part of this question by introducing an algorithm that combines prediction and minimizing information from the input, for exploratory causal discovery from observational time series. Fourthly, to make models more robust to label noise, we introduce Rank Pruning, a robust algorithm for classification with noisy labels. I believe that building on the work of my thesis we will be one step closer to enable more intelligent machines that can make sense of the world.
Early Forecasting of Text Classification Accuracy and F-Measure with Active Learning
Orth, Thomas, Bloodgood, Michael
When creating text classification systems, one of the major bottlenecks is the annotation of training data. Active learning has been proposed to address this bottleneck using stopping methods to minimize the cost of data annotation. An important capability for improving the utility of stopping methods is to effectively forecast the performance of the text classification models. Forecasting can be done through the use of logarithmic models regressed on some portion of the data as learning is progressing. A critical unexplored question is what portion of the data is needed for accurate forecasting. There is a tension, where it is desirable to use less data so that the forecast can be made earlier, which is more useful, versus it being desirable to use more data, so that the forecast can be more accurate. We find that when using active learning it is even more important to generate forecasts earlier so as to make them more useful and not waste annotation effort. We investigate the difference in forecasting difficulty when using accuracy and F-measure as the text classification system performance metrics and we find that F-measure is more difficult to forecast. We conduct experiments on seven text classification datasets in different semantic domains with different characteristics and with three different base machine learning algorithms. We find that forecasting is easiest for decision tree learning, moderate for Support Vector Machines, and most difficult for neural networks.
Exploring Visual Patterns in Projected Human and Machine Decision-Making Paths
Hinterreiter, Andreas, Steinparz, Christian, Schöfl, Moritz, Stitz, Holger, Streit, Marc
In problem solving, the paths towards solutions can be viewed as a sequence of decisions. The decisions, made by humans or computers, describe a trajectory through a high-dimensional representation space of the problem. Using dimensionality reduction, these trajectories can be visualized in lower dimensional space. Such embedded trajectories have previously been applied to a wide variety of data, but so far, almost exclusively the self-similarity of single trajectories has been analyzed. In contrast, we describe patterns emerging from drawing many trajectories---for different initial conditions, end states, or solution strategies---in the same embedding space. We argue that general statements about the problem solving tasks and solving strategies can be made by interpreting these patterns. We explore and characterize such patterns in trajectories resulting from human and machine-made decisions in a variety of application domains: logic puzzles (Rubik's cube), strategy games (chess), and optimization problems (neural network training). In the context of Rubik's cube, we present a physical interactive demonstrator that uses trajectory visualization to provide immediate feedback to users regarding the consequences of their decisions. We also discuss the importance of suitably chosen representation spaces and similarity metrics for the embedding.