2775 search results for "gis"

Thalesians, and other events

September 5, 2012
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Thalesians, and other events

Featured Thalesians, London 2012 September 12. Chia Tan on “Practical Financial Modeling”. Abstract: Financial modelling is not a competition in the mastery of complexity. Rather, the aim is to come up with the simplest models adequate to capture salient market features of traded products. There exists a wide gulf between material covered by traditional books … Continue reading...

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Interactive web graphs with R – Overview and googleVis tutorial

September 5, 2012
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Interactive web graphs with R – Overview and googleVis tutorial

Today I feel very lucky, as I have been invited to the Royal Statistical Society conference to give a tutorial on interactive web graphs with R and googleVis. I prepared my slides with RStudio, knitr, pandoc and slidy, similar to my Cambridge R talk. ...

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Installing RStan in Ubuntu

September 3, 2012
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Based on RStan Getting Started R packages Assuming you have the most up to date version of R, the following packages need to be installed. This assumes you have the c2d4u PPA available. See here for more information. sudo apt-get install r-cran-...

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Fixing non positive definite correlation matrices using R

September 3, 2012
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Problem When a correlation or covariance matrix is not positive definite (i.e., in instances when some or all eigenvalues are negative), a cholesky decomposition cannot be performed. Sometimes, these eigenvalues are very small negative numbers and occ...

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Discrete colors in ggplot

September 1, 2012
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Discrete colors in ggplot

Have you ever wanted an easy way to generate continuous color pallettes for a discrete factor? I came across a question over on Stackoverflow about how add color to a ggplot figure. I often find myself with lot’s of categories that are discrete when I want a continuous color plot. This can be achieved by writing a quick...

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Russell 2000 Softail Fat Boy

August 31, 2012
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Russell 2000 Softail Fat Boy

If the Russell 2000 were a motorcycle, maybe it should be a Harley-Davidson Softail Fat Boy.  I have explored the exception case of the Russell 2000 in quite a few posts More Exploration of Crazy RUT Where are the Fat Tails? Crazy RUT but I st...

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PCA or Polluting your Clever Analysis

August 31, 2012
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PCA or Polluting your Clever Analysis

When I learned about principal component analysis (PCA), I thought it would be really useful in big data analysis, but that's not true if you want to do prediction. I tried PCA in my first competition at kaggle, but it delivered bad results. This post illustrates how PCA can pollute good predictors.When I started examining this problem,...

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My Course Wish List at CMSE next year

August 30, 2012
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My Course Wish List at CMSE next year

Here is the list  of courses I wish to teach next year at Chiang Mai School of Economics, not so sure about the demand there! Undergraduate (B.Econ.) ECON 304: Economics Statistics (with R) ECON 408: Research Design in Economics ECON 417: Managerial Economics ECON 419: Economic Theory and Entrepreneurship ECON 443: Industrial Economics ECON 4xx: Introduction to

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Three ways of visualizing the growth of Walmart

August 30, 2012
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Three ways of visualizing the growth of Walmart

It's a wonderful thing when people make interesting data sets available to the public. When Thomas Jones wrote a paper in Econometrics about the growth of US retail giant Walmart, he made the data he collected about every Walmart store opening in history (location and date) available to the public. Since then, several people have used different techniques to...

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Making matrices with zeros and ones

August 30, 2012
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So I was trying to figure out a fast way to make matrices with randomly allocated 0 or 1 in each cell of the matrix. I reached out on Twitter, and got many responses (thanks tweeps!). Here is the solution I came up with. See if you can tell why it...

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