Publications by Matt Shotwell
useR! 2022 is almost here / casi ha llegado / approche à grands pas
[ES: Desplazándose hacia abajo por favor para el texto en español. FR: Faites défiler svp pour le text français.] Hello! The all-virtual useR! 2022 conference opens on 20 June – less than 1 month from now – with 6 keynotes, 18 tutorials, and dozens of talks and posters to choose from. Tutorial spots are first-come, first-reserved, and...
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useR! 2022 – all virtual – is next week!
Hello! The all-virtual useR! 2022 conference opens next week, on 20 June, with 6 keynotes, 18 tutorials, and dozens of talks and posters to choose from. Keynote speakers include Paola Moraga, Amanda Cox, the Afrimapr project, Julia Silge, Sebastian Meyer, and Mine Dogucu. See the program overview at the conference website: https://user2022....
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ECG Signal Processing
After reading (most of) “The Scientists and Engineers Guide to Digital Signal Processing” by Steven W. Smith, PhD, I decided to take a second crack at the ECG data. I wrote a set of R functions that implement a windowed (Blackman) sinc low-pass filter. The convolution of filter kernel with the input signal is conducted in the frequency domain...
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Matrix determinant with the Lapack routine dspsv
The Lapack routine dspsv solves the linear system of equations Ax=b, where A is a symmetric matrix in packed storage format. However, there appear to be no Lapack functions that compute the determinant of such a matrix. We need to compute the determinant, for instance, in order to compute the multivariate normal density function. The dspsv functi...
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A serial Connection for R
***UPDATED: June 3, 2010 – revert name from “tty” to “serial“, R version (2.11.1)*** I’m working on a patch for R (currently 2.11.1) that adds a serial connection feature for POSIX systems (i.e. Linux, Mac OS X, …). The serial connection works like the other connections. For example, the following code opens, writes a single byte, ...
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Collect and Parse GPS (NMEA0183) Data in R
I recently wrote a serial connection for R-2.11.0 so that I can communicate with serial devices, for example an old Garmin eTrex Legend. This GPS device is able to output NMEA0183 sentences to a standard serial port (4800,8,1,N). I hooked up the device and used the serial connection to collect some data using some R commands similar to the follow...
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House Mountain Hike
My wife Mary and my Dad Wesley and I took a hike this weekend (5/14/10) to the House Mountain state recreation area in Knox county, Tennessee. The hike was about 3.8 miles with a total elevation gain of around 1000 feet (940.23ft by GPS). The plot below gives the elevation profile over the course of the hike. Here is the Google Maps Version I’v...
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Access attribute_hidden Functions in R Packages
Maybe the title should have been prepended with “Don’t…” The source code of R is littered with “attribute_hidden” declarations. These declarations attempt to ensure that the variable or function may only be accessed by code in the core R distribution, and not by R extension packages. Generally there is a good reason for this. For exam...
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Recent picture of my niece Lily
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Picture of me with Chengwu Yang, PhD
Related To leave a comment for the author, please follow the link and comment on their blog: BioStatMatt. R-bloggers.com offers daily e-mail updates about R news and tutorials about learning R and many other topics. Click here if you're looking to post or find an R/data-science job. Want to share your content on R-bloggers? click here if you...
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