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 Statistical Learning


Top 10 Data Mining Algorithms, Explained – KioteKeet Blog

#artificialintelligence

A data mining definition Once you know what they are, how they work, what they do and where you can find them, my hope is you'll have this blog post as a springboard to learn even more about data mining. What are we waiting for? CART We also provide interesting resources at the end. 1. C4.5 What does it do? In order to do this, C4.5 is given a set of data representing things that are already classified. A classifier is a tool in data mining that takes a bunch of data representing things we want to classify and attempts to predict which class the new data belongs to.


Exploratory Data Analysis

@machinelearnbot

Notice how on the Ansombe dataset, the mean, standard deviation and correlation between x and y are almost identical. When we learn about linear regression, we will also see the same coefficients for linear regression as well. In addition to summary statistics, visualizations can be used to explore and describe data. We will learn in the tutorials the importance of visualizations, and that it is not enough to use simple statistical properties to describe data. This is demonstrated by Anscombe's quartet as outlined in this article Why Data Visualizations (are important).


Important Machine Learning Algorithms - DZone AI

#artificialintelligence

This article aims to take on a few of the machine learning algorithms for people who aim to gain knowledge on important machine learning concepts while using freely available materials and resources along the way. The prime objective of this outline is to help you wade through the numerous free options that are available. There are many, to be sure, but which are the best? What is the best order in which to use selected resources? Below are the common machine learning Algorithms briefly explained with Python and R code.


Why your geolocation skills can help in an artificial intelligence environment – DXC Blogs

@machinelearnbot

Geographic Information Systems experts have leveraged their existing knowledge of analysis, design, coding, cleansing, merging, management, and leadership -- developed from their exposure to a divergent technology landscape over many years -- to evolve and survive in a modern era beyond Google mapping. But while these geo experts may have already leveraged their existing knowledge across various fields, they may not yet realize that there is another potential option available to them. They possess the fundamental skills and capabilities necessary to understand data and data modelling, which in turn gives them the option to migrate to the world of AI. Only by working in a world of AI have I realised that the terms between the two streams are so similar. Both derive heavily from the same or similar mathematical fundamentals, design principles and concepts.


Cancer Genomics Neural Networks vs k-NN Classifiers

@machinelearnbot

Get your team access to Udemy's top 2,000 courses anytime, anywhere. Cancer Genomics Neural Networks vs k-NN Classifiers: Machine Learning for Python Hackers is a crash course in Data Science and Cancer Genomics for anyone interested in cancer research. The course starts out with loading up a cancer dataset to split train and test. This course is unique in Data Science in that it uses the mglearn library for better visualization and is dedicated to providing details as such so the student can follow along with no ambiguity.


PCA using Python (scikit-learn, pandas) Codementor

#artificialintelligence

My last tutorial went over Logistic Regression using Python. One of the things learned was that you can speed up the fitting of a machine learning algorithm by changing the optimization algorithm. A more common way of speeding up a machine learning algorithm is by using Principal Component Analysis (PCA). If your learning algorithm is too slow because the input dimension is too high, then using PCA to speed it up can be a reasonable choice. This is probably the most common application of PCA.


Kernel Robust Bias-Aware Prediction under Covariate Shift

arXiv.org Machine Learning

Under covariate shift, training (source) data and testing (target) data differ in input space distribution, but share the same conditional label distribution. This poses a challenging machine learning task. Robust Bias-Aware (RBA) prediction provides the conditional label distribution that is robust to the worstcase logarithmic loss for the target distribution while matching feature expectation constraints from the source distribution. However, employing RBA with insufficient feature constraints may result in high certainty predictions for much of the source data, while leaving too much uncertainty for target data predictions. To overcome this issue, we extend the representer theorem to the RBA setting, enabling minimization of regularized expected target risk by a reweighted kernel expectation under the source distribution. By applying kernel methods, we establish consistency guarantees and demonstrate better performance of the RBA classifier than competing methods on synthetically biased UCI datasets as well as datasets that have natural covariate shift.


Robust Covariate Shift Prediction with General Losses and Feature Views

arXiv.org Machine Learning

Covariate shift relaxes the widely-employed independent and identically distributed (IID) assumption by allowing different training and testing input distributions. Unfortunately, common methods for addressing covariate shift by trying to remove the bias between training and testing distributions using importance weighting often provide poor performance guarantees in theory and unreliable predictions with high variance in practice. Recently developed methods that construct a predictor that is inherently robust to the difficulties of learning under covariate shift are restricted to minimizing logloss and can be too conservative when faced with high-dimensional learning tasks. We address these limitations in two ways: by robustly minimizing various loss functions, including non-convex ones, under the testing distribution; and by separately shaping the influence of covariate shift according to different feature-based views of the relationship between input variables and example labels. These generalizations make robust covariate shift prediction applicable to more task scenarios. We demonstrate the benefits on classification under covariate shift tasks.


What do we need to build explainable AI systems for the medical domain?

arXiv.org Machine Learning

Artificial intelligence (AI) generally and machine learning (ML) specifically demonstrate impressive practical success in many different application domains, e.g. in autonomous driving, speech recognition, or recommender systems. Deep learning approaches, trained on extremely large data sets or using reinforcement learning methods have even exceeded human performance in visual tasks, particularly on playing games such as Atari, or mastering the game of Go. Even in the medical domain there are remarkable results. The central problem of such models is that they are regarded as black-box models and even if we understand the underlying mathematical principles, they lack an explicit declarative knowledge representation, hence have difficulty in generating the underlying explanatory structures. This calls for systems enabling to make decisions transparent, understandable and explainable. A huge motivation for our approach are rising legal and privacy aspects. The new European General Data Protection Regulation entering into force on May 25th 2018, will make black-box approaches difficult to use in business. This does not imply a ban on automatic learning approaches or an obligation to explain everything all the time, however, there must be a possibility to make the results re-traceable on demand. In this paper we outline some of our research topics in the context of the relatively new area of explainable-AI with a focus on the application in medicine, which is a very special domain. This is due to the fact that medical professionals are working mostly with distributed heterogeneous and complex sources of data. In this paper we concentrate on three sources: images, *omics data and text. We argue that research in explainable-AI would generally help to facilitate the implementation of AI/ML in the medical domain, and specifically help to facilitate transparency and trust.


Spurious Local Minima are Common in Two-Layer ReLU Neural Networks

arXiv.org Machine Learning

We consider the optimization problem associated with training simple ReLU neural networks of the form $\mathbf{x}\mapsto \sum_{i=1}^{k}\max\{0,\mathbf{w}_i^\top \mathbf{x}\}$ with respect to the squared loss. We provide a computer-assisted proof that even if the input distribution is standard Gaussian, even if the dimension is unrestricted, and even if the target values are generated by such a network, with orthonormal parameter vectors, the problem can still have spurious local minima once $k\geq 6$. By a continuity argument, this implies that in high dimensions, \emph{nearly all} target networks of the relevant sizes lead to spurious local minima. Moreover, we conduct experiments which show that the probability of hitting such local minima is quite high, and increasing with the network size. On the positive side, mild over-parameterization appears to drastically reduce such local minima, indicating that an over-parameterization assumption is necessary to get a positive result in this setting.