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Interpreting the results of linear regression – EFavDB

#artificialintelligence

The full code is available as an IPython notebook on github. Assuming a multivariate normal distribution for the residuals in linear regression allows us to construct test statistics and therefore specify uncertainty in our fits. A t-test judges the explanatory power of a predictor in isolation, although the standard error that appears in the calculation of the t-statistic is a function of the other predictors in the model. On the other hand, an F-test is a global test that judges the explanatory power of all the predictors together, and we've seen that parsimony in choosing predictors can improve the quality of the overall regression. We've also seen that multicollinearity can throw off the results of individual t-tests as well as obscure the interpretation of the signs of the fitted coefficients. A symptom of multicollinearity is when none of the individual coefficients are significant but the overall F-test is significant.


Introduction to Machine Learning in R - Udemy

@machinelearnbot

I am from Budapest, Hungary. I am qualified as a physicist and later on I decided to get a master degree in applied mathematics. At the moment I am working as a simulation engineer at a multinational company. I have been interested in algorithms and data structures and its implementations especially in Java since university. Later on I got acquainted with machine learning techniques, artificial intelligence, numerical methods and recipes such as solving differential equations, linear algebra, interpolation and extrapolation.


Probabilistic Dimensionality Reduction via Structure Learning

arXiv.org Machine Learning

We propose a novel probabilistic dimensionality reduction framework that can naturally integrate the generative model and the locality information of data. Based on this framework, we present a new model, which is able to learn a smooth skeleton of embedding points in a low-dimensional space from high-dimensional noisy data. The formulation of the new model can be equivalently interpreted as two coupled learning problem, i.e., structure learning and the learning of projection matrix. This interpretation motivates the learning of the embedding points that can directly form an explicit graph structure. We develop a new method to learn the embedding points that form a spanning tree, which is further extended to obtain a discriminative and compact feature representation for clustering problems. Unlike traditional clustering methods, we assume that centers of clusters should be close to each other if they are connected in a learned graph, and other cluster centers should be distant. This can greatly facilitate data visualization and scientific discovery in downstream analysis. Extensive experiments are performed that demonstrate that the proposed framework is able to obtain discriminative feature representations, and correctly recover the intrinsic structures of various real-world datasets.


Without-Replacement Sampling for Stochastic Gradient Methods: Convergence Results and Application to Distributed Optimization

arXiv.org Machine Learning

Stochastic gradient methods for machine learning and optimization problems are usually analyzed assuming data points are sampled \emph{with} replacement. In practice, however, sampling \emph{without} replacement is very common, easier to implement in many cases, and often performs better. In this paper, we provide competitive convergence guarantees for without-replacement sampling, under various scenarios, for three types of algorithms: Any algorithm with online regret guarantees, stochastic gradient descent, and SVRG. A useful application of our SVRG analysis is a nearly-optimal algorithm for regularized least squares in a distributed setting, in terms of both communication complexity and runtime complexity, when the data is randomly partitioned and the condition number can be as large as the data size per machine (up to logarithmic factors). Our proof techniques combine ideas from stochastic optimization, adversarial online learning, and transductive learning theory, and can potentially be applied to other stochastic optimization and learning problems.


A Deep Bag-of-Features Model for Music Auto-Tagging

arXiv.org Machine Learning

Feature learning and deep learning have drawn great attention in recent years as a way of transforming input data into more effective representations using learning algorithms. Such interest has grown in the area of music information retrieval (MIR) as well, particularly in music audio classification tasks such as auto-tagging. In this paper, we present a two-stage learning model to effectively predict multiple labels from music audio. The first stage learns to project local spectral patterns of an audio track onto a high-dimensional sparse space in an unsupervised manner and summarizes the audio track as a bag-of-features. The second stage successively performs the unsupervised learning on the bag-of-features in a layer-by-layer manner to initialize a deep neural network and finally fine-tunes it with the tag labels. Through the experiment, we rigorously examine training choices and tuning parameters, and show that the model achieves high performance on Magnatagatune, a popularly used dataset in music auto-tagging.


Introduzione all'Intelligenza Artificiale

arXiv.org Artificial Intelligence

The paper presents an introduction to Artificial Intelligence (AI) in an accessible and informal but precise form. The paper focuses on the algorithmic aspects of the discipline, presenting the main techniques used in AI systems groped in symbolic and subsymbolic. The last part of the paper is devoted to the discussion ongoing among experts in the field and the public at large about on the advantages and disadvantages of AI and in particular on the possible dangers. The personal opinion of the author on this subject concludes the paper. ----- L'articolo presenta un'introduzione all'Intelligenza Artificiale (IA) in forma divulgativa e informale ma precisa. L'articolo affronta prevalentemente gli aspetti informatici della disciplina, presentando le principali tecniche usate nei sistemi di IA divise in simboliche e subsimboliche. L'ultima parte dell'articolo presenta il dibattito in corso tra gli esperi e il pubblico su vantaggi e svantaggi dell'IA e in particolare sui possibili pericoli. L'articolo termina con l'opinione dell'autore al riguardo.


Unsupervised Machine Learning Hidden Markov Models in Python

@machinelearnbot

The Hidden Markov Model or HMM is all about learning sequences. A lot of the data that would be very useful for us to model is in sequences. Stock prices are sequences of prices. Language is a sequence of words. Credit scoring involves sequences of borrowing and repaying money, and we can use those sequences to predict whether or not you're going to default.


Civic Hall, XPRIZE & NYAI present: A.I. For Good

#artificialintelligence

CJ Adams is a product manager at Jigsaw, a subsidiary of Google's parent company Alphabet. Jigsaw uses machine learning to detect abusive language, threats, and harassment. The company is studying how computers can learn to understand the nuances and context of abusive language at scale. If successful, machine learning could help publishers and moderators improve comments on their platforms and enhance the exchange of ideas on the internet. Before joining Google, Adams worked with the Polaris Project, where he designed and built new tools for combating organized criminal networks - improving the flow of information between victims, service providers, and law enforcement officers in thousands of human trafficking cases each year.


Regression Machine Learning with Python - Udemy

@machinelearnbot

It explores main concepts from basic to expert level which can help you achieve better grades, develop your academic career, apply your knowledge at work or make business forecasting related decisions. Learning regression machine learning is indispensable for data mining applications in areas such as consumer analytics, finance, banking, health care, science, e-commerce and social media. It is also essential for academic careers in data mining, applied statistical learning or artificial intelligence. And it is necessary for any business forecasting related decision. But as learning curve can become steep as complexity grows, this course helps by leading you through step by step real world practical examples for greater effectiveness.


Changing HR : AI At Work

#artificialintelligence

Data driven recruitment has a significant, positive impact on talent management strategies and business performance. As technology becomes more sophisticated, AI is playing an increasingly essential role in decisions made around hiring and is used by brands such as Facebook as an integral part of the screening and assessment of candidates. This article examines its ongoing effect on the jobs market and the ways in which HR can harness its advantages to better understand, improve and predict hiring needs and potential problems. AI is broadly defined as'machines which perform tasks which humans are capable of performing'. It has been traditionally been regarded as a threat to jobs, with the most drastic predictions suggesting that unemployment rates will reach 50% within 30 years, but perceptions and predictions are changing.