December 2011

Fast paced food-web plotting action

December 20, 2011 | 0 Comments

A simple foodwebOne of my interests is in food web topology and food web dynamics. My research in experimental ponds has left me with 2430 food webs to make sense of, and one way to facilitate understanding that many networks, and really any food web, is through visualization. There are fancy ... [Read more...]

Tutorial on SPARQL Package for R

December 19, 2011 | 0 Comments

Tools are major enablers of Linked Science. One crucial aspect is how to access and analyze data, and especially how to get only that part of data which is of interest for a given research question.  Linked Data solves the … Continue reading → [Read more...]

Rotational Trading Strategies: borrowing ideas from Engineering Returns

December 19, 2011 | 0 Comments

Frank Hassler at Engineering Returns blog wrote an excellent article Rotational Trading: how to reduce trades and improve returns. The article presents four methods to reduce trades: Trade less frequently. I.e. weekly instead of daily rebalancing. Different criteria for enter / exit a trade. Smooth the rank over the last ... [Read more...]

Visualizing ChaLearn Gestures Test Data

December 19, 2011 | 0 Comments

The colored paths are labeled training data, just like in my last post on this.The title gives the "answer" for a test video:Could you tell from just this what the sequence of gestures was?Not perfectly, but way better than chance.See a couple more exa... [Read more...]

RTextTools v1.3.2 Released

December 19, 2011 | 0 Comments

RTextTools was updated to version 1.3.2 today, adding support for n-gram token analysis, a faster maximum entropy algorithm, and numerous bug fixes. The source code has been synced with the Google Code repository, so please feel free to check out a copy and add your own features!With the core feature ... [Read more...]

Blog Statistics with StatCounter & R

December 19, 2011 | 0 Comments

If you're interested in analysing your blog's statistics this can easily be done with a web-service like StatCounter (free, only registration needed, quite extensive service) and with R.After implementing the StatCounter script in the html code of a we...
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IRIS Flower Data Set (R-003)

December 19, 2011 | 0 Comments

Centramos la matriz con el comando, generando a partir de A una nueva matriz que llamamos "Acentered"Acentered=scale(A,center=T)Ahora con la función "eigen":Esta es otra forma de proceder con el cálculo de los componentes principales (eigenvectors y ...
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Portfolio Optimization in R, Part 2

December 19, 2011 | 0 Comments

In the previous post, we built the efficient frontier of a portfolio of bonds. The next logical step is to find the super efficient (or market) portfolio holdings.  If you are unfamiliar with the concept, take a second and read the section section... [Read more...]

Submit a paper to the R/Finance conference

December 19, 2011 | 0 Comments

For anybody using the R language to analyze financial data, the R/Finance conference is the conference of the year. If you have something to share about applied finance with R, the call for papers is now open. The details are below, and the deadline for submissions is January 31, 2012. R/... [Read more...]

Maximal Information Coefficient (MIC)

December 19, 2011 | 0 Comments

Pearson r correlation coefficients for various distributions of paired data (Credit: Denis Boigelot, Wikimedia Commons)A paper published this week in Science outlines a new statistic called the maximal information coefficient (MIC), which is able to equally describe the correlation between paired variables regardless of linear or nonlinear relationship. In ... [Read more...]

Spatial Data with R

December 19, 2011 | 0 Comments

On September 14th 2011 Dr Alec Stephenson gave a talk on exploring spatial data with R (see Meetup page). The video of the talk is now available online. The talk provides a non-mathematical and entirely equation-free talk on visualizing and … Continue reading →
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data.frame objects in R (via “R in Action”)

December 18, 2011 | 0 Comments

The followings introductory post is intended for new users of R.  It deals with R data frames: what they are, and how to create, view, and update them. This is a guest article by Dr. Robert I. Kabacoff, the founder of (one of) the first online R tutorials websites: Quick-R.  ... [Read more...]

Handwriting recognition using R

December 17, 2011 | 0 Comments

This title is a bit exaggerating since handwriting recognition is an advanced topic in machine learning involving complex techniques and algorithms. In this blog I’ll show you a simple demo illustrating how to recognize a single number (0 ~ 9) using R. The overall process is that, you draw a number in ... [Read more...]

Portfolio Optimization in R, Part 1

December 17, 2011 | 0 Comments

I briefly mentioned in my last post; that I was fooling around with portfolio optimization in R.  This post will the first in a series on the topic of portfolio optimization. Please note, nothing I am about to say should be taken as advice for investing.  These results are based ... [Read more...]

IRIS Flower Data Set (R-002)

December 17, 2011 | 0 Comments

Ver  primero: IRIS Flower Data Set (R-001)See first:        IRIS Flower Data Set (R-001)El comando "summary" nos ayuda a comprender la importancia de cada componente principal:Los "eigenvalues" son las desviacion...
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IRIS Flower Data Set (R-001)

December 17, 2011 | 0 Comments

IRIS Flower Data SetEste es el Link a Wikipedia donde podéis encontrar los datos que utilizó Fisher en su trabajo de 1936. Ya hemos trabajado con estos datos en Excel y los continuaremos usando en nuevas entradas.En este link, podemos ver las fotos de las flores (IRIS en castellano ...
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