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 Statistical Learning


Prediction Surface Uncertainty Quantification in Object Detection Models for Autonomous Driving

arXiv.org Artificial Intelligence

Object detection in autonomous cars is commonly based on camera images and Lidar inputs, which are often used to train prediction models such as deep artificial neural networks for decision making for object recognition, adjusting speed, etc. A mistake in such decision making can be damaging; thus, it is vital to measure the reliability of decisions made by such prediction models via uncertainty measurement. Uncertainty, in deep learning models, is often measured for classification problems. However, deep learning models in autonomous driving are often multi-output regression models. Hence, we propose a novel method called PURE (Prediction sURface uncErtainty) for measuring prediction uncertainty of such regression models. We formulate the object recognition problem as a regression model with more than one outputs for finding object locations in a 2-dimensional camera view. For evaluation, we modified three widely-applied object recognition models (i.e., YoLo, SSD300 and SSD512) and used the KITTI, Stanford Cars, Berkeley DeepDrive, and NEXET datasets. Results showed the statistically significant negative correlation between prediction surface uncertainty and prediction accuracy suggesting that uncertainty significantly impacts the decisions made by autonomous driving.


Out-of-Distribution Dynamics Detection: RL-Relevant Benchmarks and Results

arXiv.org Artificial Intelligence

We study the problem of out-of-distribution dynamics (OODD) detection, which involves detecting when the dynamics of a temporal process change compared to the training-distribution dynamics. This is relevant to applications in control, reinforcement learning (RL), and multi-variate time-series, where changes to test time dynamics can impact the performance of learning controllers/predictors in unknown ways. This problem is particularly important in the context of deep RL, where learned controllers often overfit to the training environment. Currently, however, there is a lack of established OODD benchmarks for the types of environments commonly used in RL research. Our first contribution is to design a set of OODD benchmarks derived from common RL environments with varying types and intensities of OODD. Our second contribution is to design a strong OODD baseline approach based on recurrent implicit quantile networks (RIQNs), which monitors autoregressive prediction errors for OODD detection. Our final contribution is to evaluate the RIQN approach on the benchmarks to provide baseline results for future comparison.


Self-service Data Classification Using Interactive Visualization and Interpretable Machine Learning

arXiv.org Artificial Intelligence

Machine learning algorithms often produce models considered as complex black-box models by both end users and developers. They fail to explain the model in terms of the domain they are designed for. The proposed Iterative Visual Logical Classifier (IVLC) is an interpretable machine learning algorithm that allows end users to design a model and classify data with more confidence and without having to compromise on the accuracy. Such technique is especially helpful when dealing with sensitive and crucial data like cancer data in the medical domain with high cost of errors. With the help of the proposed interactive and lossless multidimensional visualization, end users can identify the pattern in the data based on which they can make explainable decisions. Such options would not be possible in black box machine learning methodologies. The interpretable IVLC algorithm is supported by the Interactive Shifted Paired Coordinates Software System (SPCVis). It is a lossless multidimensional data visualization system with user interactive features. The interactive approach provides flexibility to the end user to perform data classification as self-service without having to rely on a machine learning expert. Interactive pattern discovery becomes challenging while dealing with large data sets with hundreds of dimensions/features. To overcome this problem, this chapter proposes an automated classification approach combined with new Coordinate Order Optimizer (COO) algorithm and a Genetic algorithm. The COO algorithm automatically generates the coordinate pair sequences that best represent the data separation and the genetic algorithm helps optimizing the proposed IVLC algorithm by automatically generating the areas for data classification. The feasibility of the approach is shown by experiments on benchmark datasets covering both interactive and automated processes used for data classification.


How to Learn Machine Learning – Tips and Resources to Learn ML the Practical Way

#artificialintelligence

How to Learn Machine Learning – Tips and Resources to Learn ML the Practical Way Yacine Mahdid A lot of people want to learn machine learning these days. But the daunting bottom-up curriculum that most ML teachers propose is enough discourage a lot of newcomers. In this tutorial I flip the curriculum upside down and will outline what I think is the fastest and easiest way to get a solid grasp of ML. Table of Contents Step 6: Repeat steps 0 to 5 This is a looping learning plan because the 6th step is actually a GOTO to Step 0! As a disclaimer, this curriculum might strange to you. But I've battle tested it when I was teaching machine learning to undergraduates at McGill University. I tried many iteration of this curriculum, starting with the theoretically superior bottom-up approach. But from experience, this pragmatic top-down approach is what gives the best results. One common critique I get is that people not starting with the basics, like statistics or linear algebra, will have a poor understanding of machine learning and they will not know what they are doing when modeling. In theory, yes, this is true and this is why I started teaching ML with the bottom up approach. In practice, this has never been the case. What actually ended up happening was that because the students knew how to do the high level modeling, they were much more inclined to delve into the low level stuff on their own as they saw the direct benefit it would bring to their higher level skills. This context that they were able to set for themselves wouldn't have been there if they'd started from the bottom – and this is where I believe most teachers lose their students. All that being said, let's jump into the actual learning plan!


PCA, LDA, and SVD: Model Tuning Through Feature Reduction for Transportation POI Classification

#artificialintelligence

PCA is a dimension reduction method that takes datasets with a large number of features and reduces them to a few underlying features. The sklearn PCA package performs this process for us. In the snippet of code below we are reducing the 75 features that the initial dataset has into 8 features. This snippet serves to show the optimal number of features for the feature reduction algorithm to fit into. The below snippets will show how to use the Gaussian Naive Bayes, Decision Tree, and the K-Nearest Neighbors Classifiers with the reduced features.


What is Logistic Regression?

#artificialintelligence

This tutorial is on the basics of applying logistic regression, using a little bit of Python. It is also a continuation of the post "What is Linear Regression?", which can be found here. It is a little counterintuitive, but Logistic Regression is typically used as a classifier. In fact, Logistic Regression is one of the most used and well-known classification methods Data Scientists use. The idea behind this classification method is that the output will be between 0 and 1. Essentially returning the probability that the data you gave to the model, belongs to a certain group or class.


20 Things Every Data Scientist On Coursera To Consider

#artificialintelligence

Data science courses contain math--no avoiding that! This course is designed to teach learners the basic math you will need in order to be successful in almost any data science math course and was created for learners who have basic math skills but may not have taken algebra or pre-calculus. Data Science Math Skills introduces the core math that data science is built upon, with no extra complexity, introducing unfamiliar ideas and math symbols one-at-a-time. Science is undergoing a data explosion, and astronomy is leading the way. Modern telescopes produce terabytes of data per observation, and the simulations required to model our observable Universe push supercomputers to their limits.


Artificial Intelligence Enhances Studies on Inflammatory Bowel Disease

#artificialintelligence

Inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn’s disease (CD), is an idiopathic condition related to a dysregulated immune response to commensal intestinal microflora in a genetically susceptible host. As a global disease, the morbidity of IBD reached a rate of 84.3 per 100,000 persons and reflected a continued gradual upward trajectory. The medical cost of IBD is also notably extremely high. For example, in Europe, it has €3,500 in CD and €2,000 in UC per patient per year, respectively. In addition, taking into account the work productivity loss and the reduced quality of life, the indirect costs are incalculable. In modern times, the diagnosis of IBD is still a subjective judgment based on laboratory tests and medical images. Its early diagnosis and intervention is therefore a challenging goal and also the key to control its progression. Artificial intelligence (AI)-assisted diagnosis and prognosis prediction has proven effective in many fields including gastroenterology. In this study, support vector machines were utilized to distinguish the significant features in IBD. As a result, the reliability of IBD diagnosis due to its impressive performance in classifying and addressing region problems was improved. Convolutional neural networks are advanced image processing algorithms that are currently in existence. Digestive endoscopic images can therefore be better understood by automatically detecting and classifying lesions. This study a...


Cluster Regularization via a Hierarchical Feature Regression

arXiv.org Machine Learning

Prediction tasks with high-dimensional nonorthogonal predictor sets pose a challenge for least squares based fitting procedures. A large and productive literature exists, discussing various regularized approaches to improving the out-of-sample robustness of parameter estimates. This paper proposes a novel cluster-based regularization -- the hierarchical feature regression (HFR) --, which mobilizes insights from the domains of machine learning and graph theory to estimate parameters along a supervised hierarchical representation of the predictor set, shrinking parameters towards group targets. The method is innovative in its ability to estimate optimal compositions of predictor groups, as well as the group targets endogenously. The HFR can be viewed as a supervised factor regression, with the strength of shrinkage governed by a penalty on the extent of idiosyncratic variation captured in the fitting process. The method demonstrates good predictive accuracy and versatility, outperforming a panel of benchmark regularized estimators across a diverse set of simulated regression tasks, including dense, sparse and grouped data generating processes. An application to the prediction of economic growth is used to illustrate the HFR's effectiveness in an empirical setting, with favorable comparisons to several frequentist and Bayesian alternatives.


Drug-Target Interaction Prediction with Graph Attention networks

arXiv.org Artificial Intelligence

Motivation: Predicting Drug-Target Interaction (DTI) is a well-studied topic in bioinformatics due to its relevance in the fields of proteomics and pharmaceutical research. Although many machine learning methods have been successfully applied in this task, few of them aim at leveraging the inherent heterogeneous graph structure in the DTI network to address the challenge. For better learning and interpreting the DTI topological structure and the similarity, it is desirable to have methods specifically for predicting interactions from the graph structure. Results: We present an end-to-end framework, DTI-GAT (Drug-Target Interaction prediction with Graph Attention networks) for DTI predictions. DTI-GAT incorporates a deep neural network architecture that operates on graph-structured data with the attention mechanism, which leverages both the interaction patterns and the features of drug and protein sequences. DTI-GAT facilitates the interpretation of the DTI topological structure by assigning different attention weights to each node with the self-attention mechanism. Experimental evaluations show that DTI-GAT outperforms various state-of-the-art systems on the binary DTI prediction problem. Moreover, the independent study results further demonstrate that our model can be generalized better than other conventional methods. Availability: The source code and all datasets are available at https://github.com/Haiyang-W/DTI-GRAPH