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 Statistical Learning


When Big Data Goes Local, Small Data Gets Big

#artificialintelligence

In an earlier article "The Importance of Location in Real Estate, Weather, and Machine Learning," various meanings and applications of location-based discovery in data science and machine learning were discussed. One algorithm described there is a powerful but strangely named machine learning algorithm: the Support Vector Machine (SVM). In the remarks below, we summarize the significance and utility of another powerful but strangely named machine learning algorithm that focuses on location: Local Linear Embedding (LLE). LLE is a specific example from the general category of Manifold Learning algorithms. The most famous example of manifold learning with LLE is the Swiss jelly roll example (illustrated above).


Active Learning for the Optimal Design of Multinomial Classification in Physics

arXiv.org Artificial Intelligence

Based on these facts, we conclude that most of the physics Machine learning (ML) has conquered intricate tasks in the problems can be efficiently studied by AL, if they can be past decade [1, 2]. A critical obstacle to applying ML is that equivalently represented by classification problems. Accordingly, collecting sufficient labeled data is both time-demanding and the cost of labeling is no longer limited to the fidelity resource-consuming. Consequently, model training requires loss in quantum information retrieval, but extended to the operation some sort of optimization, aiming at deriving a well-trained cost that reduces the uncertainty of samples by experimental model, even making use of numerous unlabeled data, as it protocols, including doing numerical simulations or is common real-world problems. For now, physicists also physics experiments for analyzing the most informative patterns complete quantum tasks, study properties of quantum systems, queried by AL. and design physics experiments with ML algorithms [3-In this work, we present typical applications of AL algorithms 14].


BERT-Beta: A Proactive Probabilistic Approach to Text Moderation

arXiv.org Artificial Intelligence

Text moderation for user generated content, which helps to promote healthy interaction among users, has been widely studied and many machine learning models have been proposed. In this work, we explore an alternative perspective by augmenting reactive reviews with proactive forecasting. Specifically, we propose a new concept {\it text toxicity propensity} to characterize the extent to which a text tends to attract toxic comments. Beta regression is then introduced to do the probabilistic modeling, which is demonstrated to function well in comprehensive experiments. We also propose an explanation method to communicate the model decision clearly. Both propensity scoring and interpretation benefit text moderation in a novel manner. Finally, the proposed scaling mechanism for the linear model offers useful insights beyond this work.


A Fairness Analysis on Private Aggregation of Teacher Ensembles

arXiv.org Artificial Intelligence

The Private Aggregation of Teacher Ensembles (PATE) is an important private machine learning framework. It combines multiple learning models used as teachers for a student model that learns to predict an output chosen by noisy voting among the teachers. The resulting model satisfies differential privacy and has been shown effective in learning high-quality private models in semisupervised settings or when one wishes to protect the data labels. This paper asks whether this privacy-preserving framework introduces or exacerbates bias and unfairness and shows that PATE can introduce accuracy disparity among individuals and groups of individuals. The paper analyzes which algorithmic and data properties are responsible for the disproportionate impacts, why these aspects are affecting different groups disproportionately, and proposes guidelines to mitigate these effects. The proposed approach is evaluated on several datasets and settings.


A Machine Learning Framework for Automatic Prediction of Human Semen Motility

arXiv.org Artificial Intelligence

In this paper, human semen samples from the visem dataset collected by the Simula Research Laboratory are automatically assessed with machine learning methods for their quality in respect to sperm motility. Several regression models are trained to automatically predict the percentage (0 to 100) of progressive, non-progressive, and immotile spermatozoa in a given sample. The video samples are adopted for three different feature extraction methods, in particular custom movement statistics, displacement features, and motility specific statistics have been utilised. Furthermore, four machine learning models, including linear Support Vector Regressor (SVR), Multilayer Perceptron (MLP), Convolutional Neural Network (CNN), and Recurrent Neural Network (RNN), have been trained on the extracted features for the task of automatic motility prediction. Best results for predicting motility are achieved by using the Crocker-Grier algorithm to track sperm cells in an unsupervised way and extracting individual mean squared displacement features for each detected track. These features are then aggregated into a histogram representation applying a Bag-of-Words approach. Finally, a linear SVR is trained on this feature representation. Compared to the best submission of the Medico Multimedia for Medicine challenge, which used the same dataset and splits, the Mean Absolute Error (MAE) could be reduced from 8.83 to 7.31. For the sake of reproducibility, we provide the source code for our experiments on GitHub.


Enforcing fairness in private federated learning via the modified method of differential multipliers

arXiv.org Machine Learning

Federated learning with differential privacy, or private federated learning, provides a strategy to train machine learning models while respecting users' privacy. However, differential privacy can disproportionately degrade the performance of the models on under-represented groups, as these parts of the distribution are difficult to learn in the presence of noise. Existing approaches for enforcing fairness in machine learning models have considered the centralized setting, in which the algorithm has access to the users' data. This paper introduces an algorithm to enforce group fairness in private federated learning, where users' data does not leave their devices. First, the paper extends the modified method of differential multipliers to empirical risk minimization with fairness constraints, thus providing an algorithm to enforce fairness in the central setting. Then, this algorithm is extended to the private federated learning setting. The proposed algorithm, FPFL, is tested on a federated version of the Adult dataset and an "unfair" version of the FEMNIST dataset. The experiments on these datasets show how private federated learning accentuates unfairness in the trained models, and how FPFL is able to mitigate such unfairness.


Level Sets or Gradient Lines? A Unifying View of Modal Clustering

arXiv.org Machine Learning

Up until the 1970's there were two main ways of clustering points in space. One of them, perhaps pioneered by Pearson [44], was to fit a (usually Gaussian) mixture to the data, and that being done, classify each data point -- as well as any other point available at a later date -- according to the most likely component in the mixture. The other one was based on a direct partitioning of the space, most notably by minimization of the average minimum squared distance to a center: the K-means problem, whose computational difficulty led to a number of famous algorithms [22, 31, 36, 37, 39] and likely played a role in motivating the development of hierarchical clustering [21, 25, 54, 63]. In the 1970's, two decidedly nonparametric approaches to clustering were proposed, both based on the topography given by the population density. Of course, in practice, the density is estimated, often by some form of kernel density estimation.


Information-theoretic Classification Accuracy: A Criterion that Guides Data-driven Combination of Ambiguous Outcome Labels in Multi-class Classification

arXiv.org Machine Learning

Outcome labeling ambiguity and subjectivity are ubiquitous in real-world datasets. While practitioners commonly combine ambiguous outcome labels in an ad hoc way to improve the accuracy of multi-class classification, there lacks a principled approach to guide label combination by any optimality criterion. To address this problem, we propose the information-theoretic classification accuracy (ITCA), a criterion of outcome "information" conditional on outcome prediction, to guide practitioners on how to combine ambiguous outcome labels. ITCA indicates a balance in the trade-off between prediction accuracy (how well do predicted labels agree with actual labels) and prediction resolution (how many labels are predictable). To find the optimal label combination indicated by ITCA, we develop two search strategies: greedy search and breadth-first search. Notably, ITCA and the two search strategies are adaptive to all machine-learning classification algorithms. Coupled with a classification algorithm and a search strategy, ITCA has two uses: to improve prediction accuracy and to identify ambiguous labels. We first verify that ITCA achieves high accuracy with both search strategies in finding the correct label combinations on synthetic and real data. Then we demonstrate the effectiveness of ITCA in diverse applications including medical prognosis, cancer survival prediction, user demographics prediction, and cell type classification.


Association Rule Mining -- Not Your Typical ML Algorithm

#artificialintelligence

Many mathematical algorithms that we use in data science and machine learning require numeric data. And many algorithms tend to be very complex to implement (such as Support Vector Machines or Local Linear Embedding, which we previously discussed). But, association rule mining is perfect for categorical (non-numeric) data and it involves nothing more than simple counting! What we have here is a simple algorithm with not so simplistic results! The ratio of actionable insights discovery potential (high) to algorithm complexity (low) is quite large and atypical, IMHO.


Top Data Science Crash Courses to Shape Your Career in 2021

#artificialintelligence

As the demand for data science professionals grows rapidly, students are looking for data science crash courses to gain the necessary knowledge and high-end skills needed to tackle real-world challenges. Here are the top data science courses for data aspirants to pursue. The program features a five-course series formulated to boost the foundation of data scientists in the areas of machine learning, data science, and statistics. This course is best suited for students wanting to learn big data analysis. The course gives you a deep understanding of statistics, data analysis techniques, machine learning algorithms, and probability.