Statistical Learning
Quantum algorithms for spectral sums
Luongo, Alessandro, Shao, Changpeng
The trace of matrix function, far from being only of theoretical interest, appears in many practical applications of linear algebra. To name a few, it has applications in machine learning, computational chemistry, biology, statistics, finance, and many others [1, 6, 13, 14, 24, 26, 31, 49, 52, 53]. While the problem of estimating some spectral quantities dates back to decades, many fast classical algorithms have been developed recently [7, 28, 29, 38, 47, 58, 61], highlighting the importance of spectral sums in many numerical problems. The spectral sum is defined as the sum of the eigenvalues of a matrix after a given function is applied to them. Oftentimes, the matrix will be symmetric positive definite (SPD), but there are cases where this assumption is relaxed. As an example, the logarithm of the determinant is perhaps the most common example of spectral sum, as the determinant is one of the most important properties associated with a matrix. However, the standard definition does not offer an efficient way of computing it. Remarkably, it is often the case that the logarithm of the determinant is the quantity that is effectively needed in the applications, which is much more amenable to estimation.
Towards A Sentiment Analyzer for Low-Resource Languages
Indriani, Dian, Nasution, Arbi Haza, Monika, Winda, Nasution, Salhazan
Twitter is one of the top influenced social media which has a million number of active users. It is commonly used for microblogging that allows users to share messages, ideas, thoughts and many more. Thus, millions interaction such as short messages or tweets are flowing around among the twitter users discussing various topics that has been happening world-wide. This research aims to analyse a sentiment of the users towards a particular trending topic that has been actively and massively discussed at that time. We chose a hashtag \textit{\#kpujangancurang} that was the trending topic during the Indonesia presidential election in 2019. We use the hashtag to obtain a set of data from Twitter to analyse and investigate further the positive or the negative sentiment of the users from their tweets. This research utilizes rapid miner tool to generate the twitter data and comparing Naive Bayes, K-Nearest Neighbor, Decision Tree, and Multi-Layer Perceptron classification methods to classify the sentiment of the twitter data. There are overall 200 labeled data in this experiment. Overall, Naive Bayes and Multi-Layer Perceptron classification outperformed the other two methods on 11 experiments with different size of training-testing data split. The two classifiers are potential to be used in creating sentiment analyzer for low-resource languages with small corpus.
Multi-View Dynamic Heterogeneous Information Network Embedding
Zhang, Zhenghao, Huang, Jianbin, Tan, Qinglin
Most existing Heterogeneous Information Network (HIN) embedding methods focus on static environments while neglecting the evolving characteristic of realworld networks. Although several dynamic embedding methods have been proposed, they are merely designed for homogeneous networks and cannot be directly applied in heterogeneous environment. To tackle above challenges, we propose a novel framework for incorporating temporal information into HIN embedding, denoted as Multi-View Dynamic HIN Embedding (MDHNE), which can efficiently preserve evolution patterns of implicit relationships from different views in updating node representations over time. We first transform HIN to a series of homogeneous networks corresponding to different views. Then our proposed MDHNE applies Recurrent Neural Network (RNN) to incorporate evolving pattern of complex network structure and semantic relationships between nodes into latent embedding spaces, and thus the node representations from multiple views can be learned and updated when HIN evolves over time. Moreover, we come up with an attention based fusion mechanism, which can automatically infer weights of latent representations corresponding to different views by minimizing the objective function specific for different mining tasks. Extensive experiments clearly demonstrate that our MDHNE model outperforms state-of-the-art baselines on three real-world dynamic datasets for different network mining tasks.
TensorFlow - Hands-on Machine Learning with TensorFlow
Preview this course - GET COUPON CODE Learn how to build Machine Learning projects in this TensorFlow Course created by The Click Reader. In this course, you will be learning about Scalar as well as Tensors and how to create them using TensorFlow. You will also be learning how to perform various kinds of Tensor operations for manipulating and changing tensor values. You will be performing a total of three Machine Learning projects while learning through this TensorFlow full course: 1. Linear Regression from Scratch You will be learning how to create a Linear Regression model from scratch using TensorFlow. You will be preparing the data, building the model architecture as well as training the model using a custom-made loss function as well as an optimizer.
Is AutoML ready for Business?
AutoML tools have been gaining traction for the last couple of years, both due to technological advancements and their potential to be leveraged by'Citizen Data Scientists'. Citizen Data Science, is an interesting (often controversial) aspect of Data Science (DS) that aims to automate the design of Machine Learning (ML)/Deep Learning (DL) models, making it more accessible to people without the specialized skills of a Data Scientist. In this article, we will try to understand AutoML, its promise, what is possible today?, where AutoML fails (today)?, is it meant only for Citizen Data Scientists, or does it hold some value for skilled Data Scientists as well? Let us start with a very high-level primer on Machine Learning (ML). Most of today's ML models are supervised and applied on a prediction/classification task.
Machine Learning to Predict Mortality and Critical Events in a Cohort of Patients With COVID-19 in New York City: Model Development and Validation
Background: COVID-19 has infected millions of people worldwide and is responsible for several hundred thousand fatalities. The COVID-19 pandemic has necessitated thoughtful resource allocation and early identification of high-risk patients. However, effective methods to meet these needs are lacking. Objective: The aims of this study were to analyze the electronic health records (EHRs) of patients who tested positive for COVID-19 and were admitted to hospitals in the Mount Sinai Health System in New York City; to develop machine learning models for making predictions about the hospital course of the patients over clinically meaningful time horizons based on patient characteristics at admission; and to assess the performance of these models at multiple hospitals and time points. Methods: We used Extreme Gradient Boosting (XGBoost) and baseline comparator models to predict in-hospital mortality and critical events at time windows of 3, 5, 7, and 10 days from admission. Our study population included harmonized EHR data from five hospitals in New York City for 4098 COVID-19โpositive patients admitted from March 15 to May 22, 2020. The models were first trained on patients from a single hospital (n 1514) before or on May 1, externally validated on patients from four other hospitals (n 2201) before or on May 1, and prospectively validated on all patients after May 1 (n 383). Finally, we established model interpretability to identify and rank variables that drive model predictions. Results: Upon cross-validation, the XGBoost classifier outperformed baseline models, with an area under the receiver operating characteristic curve (AUC-ROC) for mortality of 0.89 at 3 days, 0.85 at 5 and 7 days, and 0.84 at 10 days. XGBoost also performed well for critical event prediction, with an AUC-ROC of 0.80 at 3 days, 0.79 at 5 days, 0.80 at 7 days, and 0.81 at 10 days. In external validation, XGBoost achieved an AUC-ROC of 0.88 at 3 days, 0.86 at 5 days, 0.86 at 7 days, and 0.84 at 10 days for mortality prediction. Similarly, the unimputed XGBoost model achieved an AUC-ROC of 0.78 at 3 days, 0.79 at 5 days, 0.80 at 7 days, and 0.81 at 10 days.
How to Identify Overfitting Machine Learning Models in Scikit-Learn
Overfitting is a common explanation for the poor performance of a predictive model. An analysis of learning dynamics can help to identify whether a model has overfit the training dataset and may suggest an alternate configuration to use that could result in better predictive performance. Performing an analysis of learning dynamics is straightforward for algorithms that learn incrementally, like neural networks, but it is less clear how we might perform the same analysis with other algorithms that do not learn incrementally, such as decision trees, k-nearest neighbors, and other general algorithms in the scikit-learn machine learning library. In this tutorial, you will discover how to identify overfitting for machine learning models in Python. Identify Overfitting Machine Learning Models With Scikit-Learn Photo by Bonnie Moreland, some rights reserved.
Bayesian Inference of Mock NBA Draft Order
Many of us who follow the NBA Draft closely have a keen desire to know the precise ordering of the Draft, eg where each player will be taken ("where" having a dual meaning here, both the team and draft slot). To this end, it is common behavior to ingest the information we get from the dozen or more "prominent" mock drafts available leading up to the Draft. There are different ways analysts and media try to aggregate this information into what I like to call "Meta Mocks". Typically this just involves very simple operations like averaging ranks or looking at the minimum and maximum draft position. Chris Feller just the other day shared a very cool approach using survival analysis.
Robust multi-stage model-based design of optimal experiments for nonlinear estimation
Mukkula, Anwesh Reddy Gottu, Mateรกลก, Michal, Fikar, Miroslav, Paulen, Radoslav
Recently it has also become increasingly important in marketing, medicine and political sciences. Process systems engineering community adopts mathematical models successfully in various endeavors such as product and plant design, control system design, operations optimization, etc. (Pantelides and Renfro, 2013; Fung et al., 2016; Safdarnejad et al., 2016). A mathematical model is usually an abstract representation of a true system via sets of equations (algebraic, ordinary differential or partial differential), inequalities (e.g., a range of model validity), and logical conditions. Model development is usually divided into three major steps a) identification of the model structure, b) design and realization of the experiments, and c) estimation of the unknown parameters. In the latter phase, one often realizes maximum-likelihood estimation via least-squares methodology as he/she assumes--knowingly or not--that the measurement error present in the measured data is statistically distributed as a white Gaussian noise. Once the parameter estimates are known, the experimenter commonly determines the quality of the obtained model. This can be done either by using some validation data--if available--or via assessing the joint-confidence regions of the estimated parameters (Beale, 1960; Bates and Watts, 1988; Rooney and Biegler, 2001; Seber and Wild, 2003).
Generic Semi-Supervised Adversarial Subject Translation for Sensor-Based Human Activity Recognition
Soleimani, Elnaz, Khodabandelou, Ghazaleh, Chibani, Abdelghani, Amirat, Yacine
The performance of Human Activity Recognition (HAR) models, particularly deep neural networks, is highly contingent upon the availability of the massive amount of annotated training data which should be sufficiently labeled. Though, data acquisition and manual annotation in the HAR domain are prohibitively expensive due to skilled human resource requirements in both steps. Hence, domain adaptation techniques have been proposed to adapt the knowledge from the existing source of data. More recently, adversarial transfer learning methods have shown very promising results in image classification, yet limited for sensor-based HAR problems, which are still prone to the unfavorable effects of the imbalanced distribution of samples. This paper presents a novel generic and robust approach for semi-supervised domain adaptation in HAR, which capitalizes on the advantages of the adversarial framework to tackle the shortcomings, by leveraging knowledge from annotated samples exclusively from the source subject and unlabeled ones of the target subject. Extensive subject translation experiments are conducted on three large, middle, and small-size datasets with different levels of imbalance to assess the robustness and effectiveness of the proposed model to the scale as well as imbalance in the data. The results demonstrate the effectiveness of our proposed algorithms over state-of-the-art methods, which led in up to 13%, 4%, and 13% improvement of our high-level activities recognition metrics for Opportunity, LISSI, and PAMAP2 datasets, respectively. The LISSI dataset is the most challenging one owing to its less populated and imbalanced distribution. Compared to the SA-GAN adversarial domain adaptation method, the proposed approach enhances the final classification performance with an average of 7.5% for the three datasets, which emphasizes the effectiveness of micro-mini-batch training.