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 Statistical Learning


Explaining The Basics of Machine Learning, Algorithms and Applications

#artificialintelligence

"Data is abundant and cheap but knowledge is scarce and expensive." In last few years, the sources of data capturing have evolved overwhelmingly. No longer companies limit themselves to surveys, questionnaire and other traditional forms of data collection. Smartphones, online browsing activity, drones, cameras are the modern form of data collection devices. And, believe me, that data is enormous.


Cluster Analysis- Theory & workout using SAS and R

#artificialintelligence

About the course - Cluster analysis is one of the most popular techniques used in data mining for marketing needs. The idea behind cluster analysis is to find natural groups within data in such a way that each element in the group is as similar to each other as possible. At the same time, the groups are as dissimilar to other groups as possible. Course materials- The course contains video presentations (power point presentations with voice), pdf, excel work book and sas codes. Course duration- The course should take roughly 10 hours to understand and internalize the concepts.


CoolerVoid/libfast_knn

#artificialintelligence

In pattern recognition, the k-nearest neighbors algorithm (k-NN) is a non-parametric method used for classification and regression.[1] In both cases, the input consists of the k closest training examples in the feature space. In k-NN classification, the output is a class membership. An object is classified by a majority vote of its neighbors, with the object being assigned to the class most common among its k nearest neighbors (k is a positive integer, typically small). If k 1, then the object is simply assigned to the class of that single nearest neighbor.


Introduction to Python Ensembles

#artificialintelligence

Ensembles have rapidly become one of the hottest and most popular methods in applied machine learning. Virtually every winning Kaggle solution features them, and many data science pipelines have ensembles in them. Put simply, ensembles combine predictions from different models to generate a final prediction, and the more models we include the better it performs. Better still, because ensembles combine baseline predictions, they perform at least as well as the best baseline model. Ensembles give us a performance boost almost for free! An input array $X$ is fed through two preprocessing pipelines and then to a set of base learners $f {(i)}$. The ensemble combines all base learner predictions into a final prediction array $P$. In this post, we'll take you through the basics of ensembles -- what they are and why they work so well -- and provide a hands-on tutorial for building basic ensembles. To illustrate how ensembles work, we'll use a data set on U.S. political contributions.


Introduction about Logistic Regression Model

@machinelearnbot

Hello guys, we have learnt about Linear Regression model in my previous article. Today, in this article we will get to learn the basics of Logistic Regression and some tricks to find the relation between the variables. Do you know what type of variable is used in logistic regressionโ€ฆ Don't worry, if you don't know then let me teach the variables: In simple linear regression the variables are one dependent and one independent, In multiple linear regression there are more than one independent variable. Understand one thing if your data is in continuous form then use only linear regression model, while on the other hand, if your data is in categorical form(e.g. In this model the data been code in binary form.


Modern Machine Learning Algorithms: Strengths and Weaknesses

#artificialintelligence

In this guide, we'll take a practical, concise tour through modern machine learning algorithms. While other such lists exist, they don't really explain the practical tradeoffs of each algorithm, which we hope to do here. We'll discuss the advantages and disadvantages of each algorithm based on our experience. Categorizing machine learning algorithms is tricky, and there are several reasonable approaches; they can be grouped into generative/discriminative, parametric/non-parametric, supervised/unsupervised, and so on. However, from our experience, this isn't always the most practical way to group algorithms.


MEBoost: Mixing Estimators with Boosting for Imbalanced Data Classification

arXiv.org Machine Learning

Class imbalance problem has been a challenging research problem in the fields of machine learning and data mining as most real life datasets are imbalanced. Several existing machine learning algorithms try to maximize the accuracy classification by correctly identifying majority class samples while ignoring the minority class. However, the concept of the minority class instances usually represents a higher interest than the majority class. Recently, several cost sensitive methods, ensemble models and sampling techniques have been used in literature in order to classify imbalance datasets. In this paper, we propose MEBoost, a new boosting algorithm for imbalanced datasets. MEBoost mixes two different weak learners with boosting to improve the performance on imbalanced datasets. MEBoost is an alternative to the existing techniques such as SMOTEBoost, RUSBoost, Adaboost, etc. The performance of MEBoost has been evaluated on 12 benchmark imbalanced datasets with state of the art ensemble methods like SMOTEBoost, RUSBoost, Easy Ensemble, EUSBoost, DataBoost. Experimental results show significant improvement over the other methods and it can be concluded that MEBoost is an effective and promising algorithm to deal with imbalance datasets. The python version of the code is available here: https://github.com/farshidrayhanuiu/


Sparse principal component analysis via random projections

arXiv.org Machine Learning

We introduce a new method for sparse principal component analysis, based on the aggregation of eigenvector information from carefully-selected random projections of the sample covariance matrix. Unlike most alternative approaches, our algorithm is non-iterative, so is not vulnerable to a bad choice of initialisation. Our theory provides great detail on the statistical and computational trade-off in our procedure, revealing a subtle interplay between the effective sample size and the number of random projections that are required to achieve the minimax optimal rate. Numerical studies provide further insight into the procedure and confirm its highly competitive finite-sample performance.


Gradient descent GAN optimization is locally stable

arXiv.org Machine Learning

Despite the growing prominence of generative adversarial networks (GANs), optimization in GANs is still a poorly understood topic. In this paper, we analyze the "gradient descent" form of GAN optimization i.e., the natural setting where we simultaneously take small gradient steps in both generator and discriminator parameters. We show that even though GAN optimization does not correspond to a convex-concave game (even for simple parameterizations), under proper conditions, equilibrium points of this optimization procedure are still \emph{locally asymptotically stable} for the traditional GAN formulation. On the other hand, we show that the recently proposed Wasserstein GAN can have non-convergent limit cycles near equilibrium. Motivated by this stability analysis, we propose an additional regularization term for gradient descent GAN updates, which \emph{is} able to guarantee local stability for both the WGAN and the traditional GAN, and also shows practical promise in speeding up convergence and addressing mode collapse.


Predicting the Higgs-Boson Signal

@machinelearnbot

They are currently in the NYC Data Science Academy 12 week full time Data Science Bootcamp program taking place between January 11th to April 1st, 2016. This post is based on their fourth class project - Machine learning(due on the 8th week of the program). The Higgs Boson is a landmark discovery that will help us to understand the basic nature of the universe. It was discovered first by the ATLAS experiment at the Large Hadron Collider, CERN in 2012. The Higg's Boson decays into two tau particles giving rise to a small signal buried in background noise. The goal of the Higgs Boson Machine Learning Challenge was to classify the characterizing events detected by ATLAS into "tau tau decay of a Higgs boson" versus "background."