1505 search results for "tutorial"

Classification with O-PLS-DA

September 29, 2013
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Classification with O-PLS-DA

Partial least squares (PLS) is a versatile algorithm which can be used to predict either continuous or discrete/categorical variables. Classification with PLS is termed PLS-DA, where the DA stands for discriminant analysis.  The PLS-DA algorithm has many favorable properties for dealing with multivariate data; one of the most important of which is how variable collinearity is

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Introducing imagemetrics

September 25, 2013
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Introducing imagemetrics

References In my recent projects, I had the opportunity to work with the professor Raphaël Proulx who introduced me to several metrics commonly used in landscape ecology for quantifying image texture. In order to make my life easier, I decided to implement...

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Profiling R code

September 25, 2013
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Profiling R code

Profiling R code gives you the chance to identify bottlenecks and pieces of code that needs to be more efficiently implemented . Profiling R code is usually the last thing I do in the process of package (or function) development. In my experience we can reduce the amount of time necessary to run an R

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Munkres’ Assignment Algorithm with RcppArmadillo

September 24, 2013
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Munkres’ Assignment Algorithm with RcppArmadillo

Munkres’ Assignment Algorithm (Munkres (1957), also known as hungarian algorithm) is a well known algorithm in Operations Research solving the problem to optimally assign N jobs to N workers. I needed to solve the Minimal Assignment Problem for a relabeling algorithm in MCMC sampling for finite mixture distributions, where I use a random permutation Gibbs sampler. For each sample...

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analyze the home mortgage disclosure act (hmda) microdata with r and monetdb

September 23, 2013
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back in 1975, congress had it up to here with discriminatory lending practices and decided to require financial organizations originating home mortgages to report some basic operational statistics publicly.  the home mortgage disclosure act mandat...

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R GIS: Polygon Intersection with gIntersection{rgeos}

September 16, 2013
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R GIS: Polygon Intersection with gIntersection{rgeos}

A short tutorial on doing intersections in R GIS. gIntersection{rgeos} will pick the polygons of the first submitted polygon contained within the second poylgon - this is done without cutting the polygon's edges which cross the clip source polygon. For the function that I use to download the example data, url_shp_to_spdf() please see HERE. library(rgeos)library(dismo)URLs...

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paste, paste0, and sprintf

September 14, 2013
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paste, paste0, and sprintf

I find myself pasting urls and lots of little pieces together lately. Now paste is a standard go to guy when you wanna glue some stuff together. But often I find myself pasting and getting stuff like this: Rather than … Continue reading →

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In case you missed it: August 2013 Roundup

September 11, 2013
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In case you missed them, here are some articles from August of particular interest to R users: A tutorial on parallel programming with the foreach, doMC and doSNOW packages. Joe Rickert reviews R's capabilities for linear algebra, sparse matrices and big matrices. How R is disrupting the insurance industry with big data. Revolution Analytics has teamed with Cloudera to...

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Online course on forecasting using R

September 10, 2013
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I am teaming up with Revolution Analytics to teach an online course on forecasting with R. Topics to be covered include seasonality and trends, exponential smoothing, ARIMA modelling, dynamic regression and state space models, as well as forecast accuracy methods and forecast evaluation techniques such as cross-validation. I will talk about some of my consulting experiences, and explain the...

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Sentiment Analysis on Twitter with Datumbox API

September 9, 2013
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Sentiment Analysis on Twitter with Datumbox API

Hey there! After my post about sentiment analysis using the Viralheat API I found another service. Datumbox ist offering special sentiment analysis for Twitter. But this API doesn´t just offer sentiment analysis, it offers a much more detailed analysis. „The currently supported API functions are: Sentiment Analysis, Twitter Sentiment Analysis, Subjectivity Analysis, Topic Classification, Spam …

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