3132 search results for "GIS"

Mean and Median

June 8, 2013
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Mean in R is computed using the function mean. Consider the scores of 20 MSU-IIT students in Stat 101 exam with a hundred items: 70, 78, 66, 65, 50, 53, 48, 88, 95, 80, 85, 84, 81, 63, 68, 73, 75, 84, 49, and 77. Compute and interpret the mean and medi...

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Matrix Operations

June 8, 2013
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Matrix manipulation in R are very useful in Linear Algebra. Below are lists of common yet important functions in dealing operations with matrices:Transpose - tMultiplication - %*%Determinant - detInverse - solve, or ginv of MASS libraryEigenvalues and ...

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Data Class Conversion

June 6, 2013
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Data in R can be converted from one class to the other. The function is prefixed with as. then followed by the name of the data class that we wish to convert to. Data class in R are the following:numeric - as.numericvector - as.vectorcharacter - as.cha...

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How likely is the NSA PRISM program to catch a terrorist?

June 6, 2013
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How likely is the NSA PRISM program to catch a terrorist?

Recent revelations about PRISM, the NSA’s massive program of surveillance of civilian communications have caused quite a stir. And rightfully so, as it appears that the agency has been granted warrantless direct access to just about any form of digital communication engaged in by American citizens, and that their access to such data has been

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Feature Selection 3 – Swarm Mentality

June 6, 2013
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Feature Selection 3 – Swarm Mentality

"Bees don't swarm in a mango grove for nothing. Where can you see a wisp of smoke without a fire?" - Hla Stavhana In the last two posts, genetic algorithms were used as feature wrappers to search for more effective subsets of predictors. Here, I will do the same with another type of search algorithm: particle swarm optimization....

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Intro to Parallel Random Number Generation with RevoScaleR

June 6, 2013
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Intro to Parallel Random Number Generation with RevoScaleR

by Joseph Rickert Random number generation is fundamental to doing computational statistics. As you might expect, R is very rich in random number resources. The R base code provides several high quality random number generators including: Wichmann-Hill, Marsaglia-Multicarry, Super-Duper, Mersenne-Twister, Knuth-TAOCP-2002 and L’Ecuyer-CMRG. (See Random for details.) And, there are at least three packages, rspring, rlecuyer, and rstream for...

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Inputting Data in Matrix Format

June 6, 2013
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Matrix in R is formed using matrix, rbind, or cbind function. These functions have the following descriptions:matrix - used to transform a concatenated data into matrix form of compatible dimensions. rbind - short for row bind, that binds a conca...

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Major League Baseball run scoring trends with R’s Lahman package

June 4, 2013
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Major League Baseball run scoring trends with R’s Lahman package

The statistical software R has an ever-expanding array of packages that provide pre-programmed functions and datasets. One such package is named Lahman, bundling the contents of the Lahman database into a quick-and-easy resource for R users. In addition to the data tables, the package resources also contain a variety of analyses and graphics undertaken using...

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Collecting geocoded tweets with R and Java

June 4, 2013
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Collecting geocoded tweets with R and Java

Number of tweets in different languages posted around GermanyThere are many thing one can do with tweets (sentiment analysis, maps, ...). This entry shows you how you can access the publicly available API using Java and how to analyse the data using R....

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IntR – Interactive GUI for performing geostatistical analysis in R

June 4, 2013
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IntR – Interactive GUI for performing geostatistical analysis in R

In 2011 I presented at the UseR conference, held in Warwick (UK), a piece of software for easing the learning curve of R for geostatistical analysis. It is a very simple attempt to create an interactive interface in R, by using Python as GUI. F...

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