2730 search results for "GIS"

New Year’s Resolution: Learn How to Code

January 5, 2012
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Farhad Manjoo at Slate has a good article on why you need to learn how to program. Chances are, if you're reading this post here you're already fairly adept at some form of programming. But if you're not, you should give it some serious thought.Gina Trapani, former editor of tech blog Lifehacker, is quoted in the article:“Learning...

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The top 7 portfolio optimization problems

January 5, 2012
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The top 7 portfolio optimization problems

Stumbling blocks on the trek from theory to practical optimization in fund management. Problem 1: portfolio optimization is too hard If you are using a spreadsheet, then this is indeed a problem. Spreadsheets are dangerous when given a complex task.  Portfolio optimization qualifies as complex in this context (complex in data requirements). If you are … Continue reading...

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Scraping R-Bloggers with Python

January 4, 2012
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In this post I promised to show how I use Python with the BeautifulSoup and Mechanize modules to scrape information from different websites. As a fun exercise, and something that should interest the readers of R-bloggers, I thought it would be interest...

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Mapping the Iowa GOP 2012 Caucus Results

January 4, 2012
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Mapping the Iowa GOP 2012 Caucus Results

Introduction On Tuesday January 3rd 2012 the Iowa Republican party held it’s presidential caucuses, with Mitt Romney beating Rick Santorum by 8 votes as of noon on Jan 4th. This was an exciting race with multiple lead changes and entrance polling showing many late undecideds and large gaps in candidate support by age and income.

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Memoization in R : Illustrative example

January 4, 2012
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I came across a nice problem at project euler that gave me sense of satisfaction that was unusual, I think that because I don't usually get the solutions right the first time as I did in this case. Anyhow, I shall try and decode the R codes that I...

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Voting Networks in the Danish Parliament

January 2, 2012
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Voting Networks in the Danish Parliament

One of my Christmas presents was the book Beautiful Visualization. Chapter 8 by Andrew Odewahn is a very nice piece on visualizing the U.S Senate social graph. Odewahn basically builds an affinity network, where ties represent whether two senator have ...

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Uncertainty in markov chains: fun with snakes and ladders

December 31, 2011
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Uncertainty in markov chains: fun with snakes and ladders

I love board games. Over the holidays, I came across this interesting post over at Arthur Charpentier’s Freakonometrics blog about the classic game of snakes and ladders. The post is a nice little demonstration of how the game can be formulated completely as a Markov chain, and can be analysed simply using the mathematics of

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Using factor analysis or principal components analysis or measurement-error models for biological measurements in archaeology?

December 31, 2011
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Greg Campbell writes: I am a Canadian archaeologist (BSc in Chemistry) researching the past human use of European Atlantic shellfish. After two decades of practice I am finally getting a MA in archaeology at Reading. I am seeing if the habitat or size of harvested mussels (Mytilus edulis) can be reconstructed from measurements of the The post Using...

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Is R turning into an operating system?

December 31, 2011
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Is R turning into an operating system?

Over the years I convinced my colleagues and IT guys that R and LaTeX/XeLaTeX is the way forward to produce lots of customer reports with individual data, charts, analysis and text. Success!But of course the operating system in the office is still MS W...

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Benchmarking time series models

December 29, 2011
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Benchmarking time series models

This is a quick post on the importance of benchmarking time-series forecasts.  First we need to reload the functions from my last few posts on times-series cross-validation.  (I copied the relevant code at the bottom of this post so you don't...

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