2312 search results for "map"

from down-under, Lake Menteith upside-down

January 22, 2013
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from down-under, Lake Menteith upside-down

The dataset used in Bayesian Core for the chapter on image processing is a Landsat picture of Lake of Menteith in Scotland (close to Loch Lomond). (Yes, Lake of Menteith, not Loch Menteith!) Here is the image produced in the book. I just got an email from Matt Moores at QUT that the image is

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Data fishing: R and XML part 2

January 21, 2013
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Data fishing: R and XML part 2

I’m constantly amazed at what can be done using free software, such as R, and more importantly, what can be done with data that are available on the internet. In an earlier post, I confessed to my sedentary lifestyle immersed in code, so my opinion regarding the utility of open-source software is perhaps biased. None

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Montreal R User group meetup at Wajam

January 21, 2013
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Montreal R User group meetup at Wajam

This Thursday (Jan 24th), 5:30pm, the good folks at Wajam are hosting a meetup of the Montreal R User Group. The event will be at Bolidea at 4115 St Laurent, Montréal, QC. Be sure to RSVP. From Benjamin Rollert: This is an opportunity for people interested in R to hang out at our office, eat

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Coercion of matrix to sparse matrix (dgCMatrix) and maintaining dimnames.

January 20, 2013
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Coercion of matrix to sparse matrix (dgCMatrix) and maintaining dimnames.

Consider the following matrix nr <- nc <- 6 set.seed <- 123 m <- matrix(sample(c(rep(0,9), 1),nr*nc, replace=T), nrow=nr, ncol=nc) sum(m)/length(m) 0.1667 dimnames(m) <- list(letters, letters) m a b c d e f a 0 0 0 0 0 1 b 0 0 0 1 0 1 c 0 0 0 0 0 0 d 0 0 0 0 0 0 e 1 1 0 0 0 0 f 0...

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Coercion of matrix to sparse matrix (dgCMatrix) and maintaining dimnames.

January 20, 2013
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Coercion of matrix to sparse matrix (dgCMatrix) and maintaining dimnames.

Consider the following matrix nr <- nc <- 6 set.seed <- 123 m <- matrix(sample(c(rep(0,9), 1),nr*nc, replace=T), nrow=nr, ncol=nc) sum(m)/length(m) 0.1667 dimnames(m) <- list(letters, letters) m a b c d e f a 0 0 0 0 0 1 b 0 0 0 1 0 1 c 0 0 0 0 0 0 d 0 0 0 0 0 0 e 1 1 0 0 0 0 f 0...

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Sums of Random Variables

January 19, 2013
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Sums of Random Variables

I'm currently teaching first-level course in statistical inference for  (mostly) economics students. They've taken a one-semester course in descriptive (economic) statistics, and now we're dealing with sampling distributions, estimation, hypothesis testing, and simple regression analysis.When dealing with the sampling distribution of the sample mean, based on simple random sampling, we derived the result that this distribution has a...

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Power Calculations – relationship between test power, effect size and sample size

January 17, 2013
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Power Calculations – relationship between test power, effect size and sample size

I was interested in modeling the relationship between the power and sample size, while holding the significance level constant (p = 0.05) , for the common two-sample t-Test. Luckily R has great support for power analysis and I found the function I was looking for in the package pwr. To calculate the power for the two-sample T-test

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SHODAN API in R (With Examples)

January 17, 2013
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SHODAN API in R (With Examples)

Folks may debate the merits of the SHODAN tool, but in my opinion it’s a valuable resource, especially if used for “good”. What is SHODAN? I think ThreatPost summed it up nicely: “Shodan is a Web based search engine that discovers Internet facing computers, including desktops, servers and routers. The engine, created by programmer John

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Maize trade Part I: Generate the network diagram

January 17, 2013
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Maize trade Part I: Generate the network diagram

It has been several month since my last post, partially due to the fact that my laptop was lost and several deadlines was approaching. Fortunately I will be returning to Taiwan and get a new laptop within a week, and will be updating regularly...

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Review of R Graphics Cookbook by Winston Chang

January 16, 2013
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I just got a copy of Winston Chang's book R Graphics Cookbook, published by O'Reilly Media. This book follows now a series of O'Reilly books on R, including an R Cookbook. Winston Chang is a graduate student at Northwestern University but … Continue reading →

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