# 2080 search results for "gis"

## Getting started with R, for Stata users

November 19, 2013
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If you learned statistics using Stata software but have an interest in learning the R language, it's worth checking out R~Stata: Notes on Exporing Data by Princeton's Oscar Torres-Reyna. D-Lab's Laura Nelson provides an overview, but in short it's a collection of 30 PDF slides that introduces R for Stata users, and provides translation tables like the one below...

## Calling R from the ERP – A dirty little hack

November 19, 2013
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Since I joined SAP around 2 years ago, I simply stopped using ABAP…even when I use it for almost 11 years when I was a consultant…A week ago, I was thinking about writing a new blog…something nice…some hacky…something that would allow me to just rest and don’t blog for the rest of the year…I thought about ERP and R…while...

## Predicting claims with a bayesian network

November 19, 2013
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Here is a little Bayesian Network to predict the claims for two different types of drivers over the next year, see also example 16.16 in . Let's assume there are good and bad drivers. The probabilities that a good driver will have 0, 1 or 2 claims in any given year are set to 70%, 20% and 10%,...

## Binomial regression model

November 18, 2013
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$Y_i\sim\mathcal{B}(p(\boldsymbol{X_i}))$

Most of the time, when we introduce binomial models, such as the logistic or probit models, we discuss only Bernoulli variables, . This year (actually also the year before), I discuss extensions to multinomial regressions, where  is a function on some simplex. The multinomial logistic model was mention here. The idea is to consider, for instance with three possible classes the following...

## Success rates for EPSRC Fellowships

November 18, 2013
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Email I was recently at a presentation where the success rates for EPSRC fellowships were given by theme. The message of the talk was that Engineering fellowships were under-subscribed and so we should all be preparing our applications. But just because a theme is under-subcribed doesn’t mean that you’ve got a better chance of getting

## Some Options for Testing Tables

November 18, 2013
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Contingency tables are a very good way to summarize discrete data.  They are quite easy to construct and reasonably easy to understand. However, there are many nuances with tables and care should be taken when making conclusions related to the data. Here are just a few thoughts on the topic. Dealing with sparse data On

## Evaluating Quandl Data Quality

November 15, 2013
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Quandl has indexed millions of time-series datasets from over 400 sources. All of Quandl’s datasets are open and free. This is great news but before performing any backtest using Quandl data, I want to compare it with a trusted source: Bloomberg for the purpose of this post. I will focus only on daily Futures data here

## Visualizing neural networks in R – update

November 14, 2013
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In my last post I said I wasn’t going to write anymore about neural networks (i.e., multilayer feedforward perceptron, supervised ANN, etc.). That was a lie. I’ve received several requests to update the neural network plotting function described in the original post. As previously explained, R does not provide a lot of options for visualizing

## Iterators in R

November 13, 2013
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According to Wikipedia, an iterator is “an object that enables a programmer to traverse a container”. A collection of items (stashed in a container) can be thought of as being “iterable” if there is a logical progression from one element to the next (so a list is iterable, while a set is not). An iterator