Statistical Learning
A Beginner's Guide to Supervised Machine Learning Algorithms
An overview of supervised machine learning algorithms that are commonly used. Supervised learning algorithms try to predict a target (dependent variable) using features (independent variables). Depending on the characteristics of target variable, it can be a classification (discrete target variable) or a regression (continuous target variable) task. If you are here reading this post, you are well aware of the importance of machine learning. Prevalence of machine learning has been increasing tremendously in the recent years due to the high demand in many business areas and the advancements in technology.
Predicting Used Car Prices with Machine Learning
The prices of new cars in the industry is fixed by the manufacturer with some additional costs incurred by the Government in the form of taxes. So, customers buying a new car can be assured of the money they invest to be worthy. But due to the increased price of new cars and the incapability of customers to buy new cars due to the lack of funds, used cars sales are on a global increase (Pal, Arora and Palakurthy, 2018). There is a need for a used car price prediction system to effectively determine the worthiness of the car using a variety of features. Even though there are websites that offers this service, their prediction method may not be the best. Besides, different models and systems may contribute on predicting power for a used car's actual market value. It is important to know their actual market value while both buying and selling. To be able to predict used cars market value can help both buyers and sellers. Used car sellers (dealers): They are one of the biggest target group that can be interested in results of this study. If used car sellers better understand what makes a car desirable, what the important features are for a used car, then they may consider this knowledge and offer a better service. Online pricing services: There are websites that offers an estimate value of a car. They may have a good prediction model.
Machine Learning Field Guide
We all have to deal with data, and we try to learn about and implement machine learning into our projects. But everyone seems to forget one thing... it's far from perfect, and there is so much to go through! Don't worry, we'll discuss every little step, from start to finish . All you'll need are these fundementals We all start with either a dataset or a goal in mind. Once we've found, collected or scraped our data, we pull it up, and witness the overwhelming sight of merciless cells of numbers, more numbers, categories, and maybe some words! A naive thought crosses our mind, to use our machine learning prowess to deal with this tangled mess... but a quick search reveals the host of tasks we'll need to consider before training a model! Once we overcome the shock of our unruly data we look for ways to battle our formidable nemesis . We start with trying to get our data into Python.
How to Build and Train Linear and Logistic Regression ML Models in Python
Linear regression and logistic regression are two of the most popular machine learning models today. In the last lesson of this course, you learned about the history and theory behind a linear regression machine learning algorithm. This tutorial will teach you how to create, train, and test your first linear regression machine learning model in Python using the scikit-learn library. In the last lesson of this course, you learned about the history and theory behind a linear regression machine learning algorithm. This tutorial will teach you how to create, train, and test your first linear regression machine learning model in Python using the scikit-learn library. Since linear regression is the first machine learning model that we are learning in this course, we will work with artificially-created datasets in this tutorial.
Challenges in Benchmarking Stream Learning Algorithms with Real-world Data
Souza, Vinicius M. A., Reis, Denis M. dos, Maletzke, Andre G., Batista, Gustavo E. A. P. A.
Streaming data are increasingly present in real-world applications such as sensor measurements, satellite data feed, stock market, and financial data. The main characteristics of these applications are the online arrival of data observations at high speed and the susceptibility to changes in the data distributions due to the dynamic nature of real environments. The data stream mining community still faces some primary challenges and difficulties related to the comparison and evaluation of new proposals, mainly due to the lack of publicly available non-stationary real-world datasets. The comparison of stream algorithms proposed in the literature is not an easy task, as authors do not always follow the same recommendations, experimental evaluation procedures, datasets, and assumptions. In this paper, we mitigate problems related to the choice of datasets in the experimental evaluation of stream classifiers and drift detectors. To that end, we propose a new public data repository for benchmarking stream algorithms with real-world data. This repository contains the most popular datasets from literature and new datasets related to a highly relevant public health problem that involves the recognition of disease vector insects using optical sensors. The main advantage of these new datasets is the prior knowledge of their characteristics and patterns of changes to evaluate new adaptive algorithm proposals adequately. We also present an in-depth discussion about the characteristics, reasons, and issues that lead to different types of changes in data distribution, as well as a critical review of common problems concerning the current benchmark datasets available in the literature.
Sparse Gaussian Processes with Spherical Harmonic Features
Dutordoir, Vincent, Durrande, Nicolas, Hensman, James
We introduce a new class of inter-domain variational Gaussian processes (GP) where data is mapped onto the unit hypersphere in order to use spherical harmonic representations. Our inference scheme is comparable to variational Fourier features, but it does not suffer from the curse of dimensionality, and leads to diagonal covariance matrices between inducing variables. This enables a speed-up in inference, because it bypasses the need to invert large covariance matrices. Our experiments show that our model is able to fit a regression model for a dataset with 6 million entries two orders of magnitude faster compared to standard sparse GPs, while retaining state of the art accuracy. We also demonstrate competitive performance on classification with non-conjugate likelihoods.
The computerization of archaeology: survey on AI techniques
Mantovan, Lorenzo, Nanni, Loris
This paper analyses the application of artificial intelligence techniques to various areas of archaeology and more specifically: a) The use of software tools as a creative stimulus for the organization of exhibitions; the use of humanoid robots and holographic displays as guides that interact and involve museum visitors; b) The analysis of methods for the classification of fragments found in archaeological excavations and for the reconstruction of ceramics, with the recomposition of the parts of text missing from historical documents and epigraphs; c) The cataloguing and study of human remains to understand the social and historical context of belonging with the demonstration of the effectiveness of the AI techniques used; d) The detection of particularly difficult terrestrial archaeological sites with the analysis of the architectures of the Artificial Neural Networks most suitable for solving the problems presented by the site; the design of a study for the exploration of marine archaeological sites, located at depths that cannot be reached by man, through the construction of a freely explorable 3D version.
Does the Whole Exceed its Parts? The Effect of AI Explanations on Complementary Team Performance
Bansal, Gagan, Wu, Tongshuang, Zhou, Joyce, Fok, Raymond, Nushi, Besmira, Kamar, Ece, Ribeiro, Marco Tulio, Weld, Daniel S.
Increasingly, organizations are pairing humans with AI systems to improve decision-making and reducing costs. Proponents of human-centered AI argue that team performance can even further improve when the AI model explains its recommendations. However, a careful analysis of existing literature reveals that prior studies observed improvements due to explanations only when the AI, alone, outperformed both the human and the best human-AI team. This raises an important question: can explanations lead to complementary performance, i.e., with accuracy higher than both the human and the AI working alone? We address this question by devising comprehensive studies on human-AI teaming, where participants solve a task with help from an AI system without explanations and from one with varying types of AI explanation support. We carefully controlled to ensure comparable human and AI accuracy across experiments on three NLP datasets (two for sentiment analysis and one for question answering). While we found complementary improvements from AI augmentation, they were not increased by state-of-the-art explanations compared to simpler strategies, such as displaying the AI's confidence. We show that explanations increase the chance that humans will accept the AI's recommendation regardless of whether the AI is correct. While this clarifies the gains in team performance from explanations in prior work, it poses new challenges for human-centered AI: how can we best design systems to produce complementary performance? Can we develop explanatory approaches that help humans decide whether and when to trust AI input?
Similarity Search for Efficient Active Learning and Search of Rare Concepts
Coleman, Cody, Chou, Edward, Culatana, Sean, Bailis, Peter, Berg, Alexander C., Sumbaly, Roshan, Zaharia, Matei, Yalniz, I. Zeki
Many active learning and search approaches are intractable for industrial settings with billions of unlabeled examples. Existing approaches, such as uncertainty sampling or information density, search globally for the optimal examples to label, scaling linearly or even quadratically with the unlabeled data. However, in practice, data is often heavily skewed; only a small fraction of collected data will be relevant for a given learning task. For example, when identifying rare classes, detecting malicious content, or debugging model performance, the ratio of positive to negative examples can be 1 to 1,000 or more. In this work, we exploit this skew in large training datasets to reduce the number of unlabeled examples considered in each selection round by only looking at the nearest neighbors to the labeled examples. Empirically, we observe that learned representations effectively cluster unseen concepts, making active learning very effective and substantially reducing the number of viable unlabeled examples. We evaluate several active learning and search techniques in this setting on three large-scale datasets: ImageNet, Goodreads spoiler detection, and OpenImages. For rare classes, active learning methods need as little as 0.31% of the labeled data to match the average precision of full supervision. By limiting active learning methods to only consider the immediate neighbors of the labeled data as candidates for labeling, we need only process as little as 1% of the unlabeled data while achieving similar reductions in labeling costs as the traditional global approach. This process of expanding the candidate pool with the nearest neighbors of the labeled set can be done efficiently and reduces the computational complexity of selection by orders of magnitude.
Nonparametric Score Estimators
Zhou, Yuhao, Shi, Jiaxin, Zhu, Jun
Estimating the score, i.e., the gradient of log density function, from a set of samples generated by an unknown distribution is a fundamental task in inference and learning of probabilistic models that involve flexible yet intractable densities. Kernel estimators based on Stein's methods or score matching have shown promise, however their theoretical properties and relationships have not been fully-understood. We provide a unifying view of these estimators under the framework of regularized nonparametric regression. It allows us to analyse existing estimators and construct new ones with desirable properties by choosing different hypothesis spaces and regularizers. A unified convergence analysis is provided for such estimators. Finally, we propose score estimators based on iterative regularization that enjoy computational benefits from curl-free kernels and fast convergence.