1286 search results for "excel"

Getting data from an image (introductory post)

March 5, 2010
By
Getting data from an image (introductory post)

Hi there! This blog will be dedicated to data visualization in R. Why? Two reasons. First, when it comes to statistics, I am always starting by some exploratory analyses, mostly with plots. And when I handle large quantities of data, it’s nice to make some graphs to get a grasp about what is going on.

Read more »

Quality trimming in R using ShortRead and Biostrings

March 3, 2010
By

I wrote an R function to do soft-trimming, right clipping FastQ reads based on quality.This function has the option of leaving out sequences trimmed to extinction and will do left-side fixed trimming as well.#softTrim#trim first position lower than minQuality and all subsequent positions#omit sequences that after trimming are shorter than minLength#left trim to firstBase, (1 implies no left trim)#input:...

Read more »

Quality trimming in R using ShortRead and Biostrings

March 3, 2010
By

I wrote an R function to do soft-trimming, right clipping FastQ reads based on quality.This function has the option of leaving out sequences trimmed to extinction and will do left-side fixed trimming as well.#softTrim#trim first position lower than minQuality and all subsequent positions#omit sequences that after trimming are shorter than minLength#left trim to firstBase, (1 implies no left trim)#input:...

Read more »

Interaction plot from cell means

February 24, 2010
By
Interaction plot from cell means

I needed to produce a few a interaction plots for my book in R and, while the interaction.plot() function is useful it has a couple of drawbacks. First, the default output isn't very pretty. Second, it works from the raw data, whereas I often need plot...

Read more »

Numerical Integration/Differentiation in R: FTIR Spectra

February 23, 2010
By
Numerical Integration/Differentiation in R: FTIR Spectra

  Stumbled upon an excellent example of how to perform numerical integration in R. Below is an example of piece-wise linear and spline fits to FTIR data, and the resulting computed area under the curve. With a high density of points, it seems like the linear approximation is most efficient and sufficiently accurate. With very large...

Read more »

Genetic Algorithm Systematic Trading Development — Part 3 (Python/VBA)

February 20, 2010
By
Genetic Algorithm Systematic Trading Development — Part 3  (Python/VBA)

As mentioned in prior posts, it is not possible to use the standard Weka GUI to instantiate a Genetic Algorithm, other than for feature selection. Part of the reason is that there is no generic algorithm to instantiate a fitness function. The same fl...

Read more »

Practical Implementation of Neural Network based time series (stock) prediction -PART 5

February 7, 2010
By
Practical Implementation of Neural Network based time series (stock) prediction  -PART 5

Following is an example of what it looks like to predict an actual univariate price series. The period of the signal that was sampled was already in stationary form, so not much massaging was needed other than normalization (described earlier).What's ...

Read more »

Eight R Video Tutorials on VCASMO

February 4, 2010
By

Download "Getting Started with the Social Media Analytics Research Toolkit" (pdf, 1.25 megabytes) Download the Social Media Analytics Research Toolkit Thanks to Drew Conway (@drewconway), a PhD student at New York University, there are now eight excell...

Read more »

Predicting the Locations of ‘Emergency’ Ushahidi Reports in Port-au-Prince, and Implications for Crowdsourcing

February 2, 2010
By
Predicting the Locations of ‘Emergency’ Ushahidi Reports in Port-au-Prince, and Implications for Crowdsourcing

Recently, Patrick Meier, PhD candidate at Tufts University and member of the Ushahidi Advisory Board, provided me with a dataset containing the first 72 hours of reports registered with Ushahidi in Port-au-Prince after the January 12th earthquake. First, a huge thank you to Patrick for providing me with this data and the opportunity to analyze

Read more »

Practical Implementation of Neural Network based time series (stock) prediction – PART 2

January 30, 2010
By
Practical Implementation of Neural Network based time series (stock) prediction – PART 2

As a brief follow up to the series, I want to take a moment to describe a bit about Weka, which is the machine learning tool that we will be using to implement the neural network. It is a fantastic open source JAVA based tool that was developed at the...

Read more »