I bought a pair of Lilygo T-Echo radios with meshtastic firmware two years ago for my birthday, but I had limited success connecting to anyone.
Suddenly, a couple of weeks ago I started seeing radio traffic from Carolina to Caguas. It looks like someone close to my house set up …
more ...When I was a wee hacker I wrote a manual for using the Internet, which had recently become available to researchers at the University of Puerto Rico. The Office of Information Systems later updated and republished the manual, and there are several copies in the UPR library system. Yesterday I …
more ...I got eclipse glasses from the EcoExploratorio and we saw part of the eclipse on Saturday, October 14, 2023.
Around 2:00 PM AST (18:00 UTC) it got cloudy, and we lost our chance to see the maximum extent, which happened around 2:24 PM. Fortunately, we have access …
more ...Hace unos meses compartí acerca de las mujeres en la ciencia (de cómputos). Cuando escribí eso, sentí que se quedaron fuera varias mujeres que han sido importantes en mi carrera. Pero no en el aspecto de la ciencia de computos, sino por otras razones.
Y aqui hay un efecto curioso …
more ...La Dra. Liz Diaz me invitó a participar del Segundo Simposio El Poder de la Mujer en las Ciencias, el 15 y 16 de abril de 2021. Se supone que para presentar los programas de ciencia de computos. Pero su invitación y el tema de la conferencia me hicieron …
more ...While learning about Mastodon and the fediverse (more on that later, in a separate post), I ran across a group of people learning and working with Plan 9. Plan 9 is an operating system developed at Bell Labs in the 1990's, a sort of successor to some of the ideas …
more ...I sometimes direct the UPR High Performance Computing facility, or as my colleagues like to call it, the medium performance computing facility. We've run largish linux clusters and big sgi machines since the early naughts.
So it's a little surprising I'm also interested in low-power computing. Until you hear …
more ...It's been a few months since I wrote anything in the blog. Like everyone, I've been busy with the Covid-19 pandemic. We moved all classes online in March, and Fall 2020 is online only too. Teaching online is hard, maybe as hard as learning online. I'm grateful to the Carpentries …
more ...Puerto Rico had a swarm (or sequence) of earthquakes at the end of 2019 and the start of 2020. So far, the largest was a magnitude 6.4 on January 7, 2020.
Since around December 28, there have been hundreds of quakes in the region. Several researchers have made …
more ...I just ran a Software Carpentry Introduction to R Programming workshop with Sofia Melendez for the IQ-Bio-REU. We had three great helpers, Briknie Baez, Israel Dilán, and Marc De Jesus Ellsworth. With Juan S Ramirez lending moral support as needed. We ran the workshop over 5 half-days instead of the …
more ...During the 2015 drought I wrote niveles-carraizo, an openshift app to monitor the water levels at the reservoir close to my home. Openshift changed the way apps work, so the app stopped working a while back.
The app used a cronjob to scrape data from our water works, but …
more ...We were discussing in our department the pre-requisites for different courses in computer science, and I started wondering about the "normal progression" of students in our Computer Science bachellor's degree. We have a suggested 4 year curriculum, but hardly any students graduate in 4 years. I wanted to see …
more ...I watched a nice video today of a lecture by Rob Pike on the history of UNIX from his personal perspective. It's fun to watch stuff like this, it's different than reading about UNIX in a book or online.
I once had the opportunity to watch Linus Pauling give a …
more ...The University of Puerto Rico has a G Suite Education Edition agreement. Several researchers are interested in using Google Drive to backup and securely share data and results. We set up a Team Drive for testing in one of our projects, and it was working nicely, but one of …
more ...After Hurricane Maria hit Puerto Rico on September 20, 2017 I bought a solar panel kit. The kit had a 100 Watt solar panel (12 V), a charge controller, and cabling. I had already purchased a 1200 Watt inverter after Hurricane Irma, and pulled the battery from one of the …
more ...We've done a few performance evaluations of high performance computing hardware at the HPCf, but this is the first one we've published.
Eric Gamess and Humberto Ortiz-Zuazaga, "Analytical Performance Evaluation of Ipv6 and Ipv4 Over 10 Gigabit Ethernet and Infiniband using Ipoib" International Journal of Advanced Computer Science and Applications …
more ...C. TItus Brown showed us this really cool service called binder in the mRNAseq data analysis workshop on Saturday.
If you go to
and paste in a github repository like
https://github.com/humberto-ortiz/ama
that contains some data and some jupyter notebooks, binder will redirect you …
more ...Theorem 1. In a uniform juggle with dwell time \(D\), vacant time \(V\), flight time \(F\) then
$$\frac{F+D}{V+D}=\frac{B}{H},$$where \(B\) is the number of balls and \(H\) the number of hands.
Scientific Aspects of Juggling.
In Claude Elwood Shannon: Collected Papers. Edited by …
more ...We're in the middle of an extended draught, and water has been rationed for almost a month in most of the metropolitan area.
I made an openshift app using Flask and pygal to scrape the data from the water authority's page and plot it.
The source code for everything is …
more ...I'm very proud of my undergraduate students this semester. They put in a lot of effort, and it shows. Go see our lab page and look for their presentations and technical reports.
There are five technical reports on network flows, graph algorithms, cybersecurity and sequence assembly, and about as many …
more ...After a long hiatus running Mac OS X, I decided to return to linux on my main PC. My MacBook is showing signs of dying, and a hard drive crash during a backup made me finally decide to get a new machine.
I got a HP Pavilion 13-A010dx X360 …
more ...I’ve been interested in network flows for a long time. In Fall 2013, Iván García started working in my lab on detecting anomalies in network flows. Here’s his technical report on the topic.
more ...I went to the 2014 Tech Summit Hackathon, but knew I had to leave early, so I did a solo hack.
One of the newly released data sets included some historical GPS data from the Autoridad Metropolitana de Autobuses. I decided to try to look at the bus service on …
more ...Slideshow on the use of scala at twitter to build distrubuted systems. They use the applicative and functional aspects to compose applications as layers of interfaces.
Twitter is heavy into scala, they have courses and best practices too.
more ...Christian A. Rodriguez showed me his MathJax enabled pages, and I just found out org-mode supports mathjax too. You just put latex equations in html, and load the javascript. It renders the equation in any browser.
Here's an example from the MathJax home page:
The raw latex:
$$ J_\alpha(x …Cassandra went to MIT CONVERGE for the weekend and left me her Duncan Juggling Rings. I got a little practice in with them yesterday and today. They're not fancy, but they work. I hope I can practice enough I can take a stab at dinner plates! I also juggled a …
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