Statistical Learning
An Ensemble Boosting Model for Predicting Transfer to the Pediatric Intensive Care Unit
Rubin, Jonathan, Potes, Cristhian, Xu-Wilson, Minnan, Dong, Junzi, Rahman, Asif, Nguyen, Hiep, Moromisato, David
Our work focuses on the problem of predicting the transfer of pediatric patients from the general ward of a hospital to the pediatric intensive care unit. Using data collected over 5.5 years from the electronic health records of two medical facilities, we develop classifiers based on adaptive boosting and gradient tree boosting. We further combine these learned classifiers into an ensemble model and compare its performance to a modified pediatric early warning score (PEWS) baseline that relies on expert defined guidelines. To gauge model generalizability, we perform an inter-facility evaluation where we train our algorithm on data from one facility and perform evaluation on a hidden test dataset from a separate facility. We show that improvements are witnessed over the PEWS baseline in accuracy (0.77 vs. 0.69), sensitivity (0.80 vs. 0.68), specificity (0.74 vs. 0.70) and AUROC (0.85 vs. 0.73).
Theoretical insights into the optimization landscape of over-parameterized shallow neural networks
Soltanolkotabi, Mahdi, Javanmard, Adel, Lee, Jason D.
In this paper we study the problem of learning a shallow artificial neural network that best fits a training data set. We study this problem in the over-parameterized regime where the number of observations are fewer than the number of parameters in the model. We show that with quadratic activations the optimization landscape of training such shallow neural networks has certain favorable characteristics that allow globally optimal models to be found efficiently using a variety of local search heuristics. This result holds for an arbitrary training data of input/output pairs. For differentiable activation functions we also show that gradient descent, when suitably initialized, converges at a linear rate to a globally optimal model. This result focuses on a realizable model where the inputs are chosen i.i.d. from a Gaussian distribution and the labels are generated according to planted weight coefficients.
Snake oil and Piรฑa Colada: Will I Survive the Artificial Intelligence Summer of Love?
I have been around the block for a while and I have seen this happening already in a form or another but this time is big. This time is crazy big. I am talking about the machine learning madness that took over everything. Long time ago in the field of computer science a brand new area of research was born: we were in the 60s and this new field of investigation aimed at understanding how the human mind worked was -- without false modesty -- called artificial intelligence. The general idea was that if you are able to create something that looks intelligent or indistinguishable from something intelligent, then, it must be intelligent.
Time for a change: a tutorial for comparing multiple classifiers through Bayesian analysis
Benavoli, Alessio, Corani, Giorgio, Demsar, Janez, Zaffalon, Marco
The machine learning community adopted the use of null hypothesis significance testing (NHST) in order to ensure the statistical validity of results. Many scientific fields however realized the shortcomings of frequentist reasoning and in the most radical cases even banned its use in publications. We should do the same: just as we have embraced the Bayesian paradigm in the development of new machine learning methods, so we should also use it in the analysis of our own results. We argue for abandonment of NHST by exposing its fallacies and, more importantly, offer better - more sound and useful - alternatives for it.
On the Performance of Forecasting Models in the Presence of Input Uncertainty
Sangrody, Hossein, Sarailoo, Morteza, Zhou, Ning, Shokrollahi, Ahmad, Foruzan, Elham
Nowadays, with the unprecedented penetration of renewable distributed energy resources (DERs), the necessity of an efficient energy forecasting model is more demanding than before. Generally, forecasting models are trained using observed weather data while the trained models are applied for energy forecasting using forecasted weather data. In this study, the performance of several commonly used forecasting methods in the presence of weather predictors with uncertainty is assessed and compared. Accordingly, both observed and forecasted weather data are collected, then the influential predictors for solar PV generation forecasting model are selected using several measures. Using observed and forecasted weather data, an analysis on the uncertainty of weather variables is represented by MAE and bootstrapping. The energy forecasting model is trained using observed weather data, and finally, the performance of several commonly used forecasting methods in solar energy forecasting is simulated and compared for a real case study.
End-to-End Learning for Structured Prediction Energy Networks
Belanger, David, Yang, Bishan, McCallum, Andrew
Structured Prediction Energy Networks (SPENs) are a simple, yet expressive family of structured prediction models (Belanger and McCallum, 2016). An energy function over candidate structured outputs is given by a deep network, and predictions are formed by gradient-based optimization. This paper presents end-to-end learning for SPENs, where the energy function is discriminatively trained by back-propagating through gradient-based prediction. In our experience, the approach is substantially more accurate than the structured SVM method of Belanger and McCallum (2016), as it allows us to use more sophisticated non-convex energies. We provide a collection of techniques for improving the speed, accuracy, and memory requirements of end-to-end SPENs, and demonstrate the power of our method on 7-Scenes image denoising and CoNLL-2005 semantic role labeling tasks. In both, inexact minimization of non-convex SPEN energies is superior to baseline methods that use simplistic energy functions that can be minimized exactly.
What's New in MATLAB Data Analytics - MATLAB & Simulink
Use neighborhood component analysis (NCA) to choose features for machine learning models. Manipulate and analyze data that is too big to fit in memory. Perform support vector machine (SVM) and Naive Bayes classification, create bags of decision trees, and fit lasso regression on out-of-memory data. Process big data with tall arrays in parallel on your desktop, MATLAB Distributed Computing Server, and Spark clusters. Manipulate, compare, and store text data efficiently .
10 Algorithms Machine Learning Engineers Need To Know About
With the fast mechanization brought about by the technological revolution, the word manual is slowly getting lost amidst the crowd and will very soon completely vanish. As Big Data has whisked the tech industry, Machine Learning is gaining importance and has robustly handled huge amount of data making accurate predictions. In an era of constant progress, we can only guess what astounding invention and discovery is to come next. The data-crunching machines that have been seamlessly executing the advanced techniques. Machine learning is a subset of the Artificial Intelligence, which is a broader term and concept.
The Best Metric to Measure Accuracy of Classification Models
To understand the implication of translating the probability number, let's understand few basic concepts relating to evaluating a classification model with the help of an example given below. Since we are now comfortable with the interpretation of the Confusion Matrix, let's look at some popular metrics used for testing the classification models: Since the formula doesn't contain FP and TN, Sensitivity may give you a biased result, especially for imbalanced classes. In the example of Fraud detection, it gives you the percentage of Correctly Predicted Frauds from the pool of Actual Frauds. In the example of Fraud detection, it gives you the percentage of Correctly Predicted Frauds from the pool of Total Predicted Frauds.