TCP weirdness, IMAP, wireshark, and perdition

February 10, 2010

Seen on Planet Debian: a nice writeup of a debugging session with a user watching over his shoulder.

One thing to note about user empowerment: Fred isn’t a tech geek, but he can be curious about the technology he relies on if the situation is right. He was with me through the whole process, didn’t get antsy, and never tried to get me to "just fix it" while he did something else. I like that, and wish i got to have that kind of interaction more (though i certainly don’t begrudge people the time if they do need to get other things done). I was nervous about breaking out wireshark and scaring him off with it, but it turned out it actually was a good conversation starter about what was actually happening on the network, and how IP and TCP traffic worked.

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Polynomial Regression in R

January 16, 2010

If you find yourself trying to do a polynomial regression in R, you may find Polynomial Regression in R by Bret Larget extremely helpful. I always have a hard time remembering the I(x^2) syntax. The explanations of the underlying statistics are also useful if you already know a little bit of what’s going on.

While r2 has this nice interpretation, its major deficiency is that it will always increase as you add additional variables — the residual sum of squares from a small model must be at least as large as that from a larger model of which it is a special case. So, looking at r2 is not a good strategy for picking out a good model, because you can get increasingly better r2 values by addiing spurious variables. One attempt to correct for this is to compute the adjusted r2 statistic.

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Learning is Childsplay

January 3, 2010

Seen on LWN, a review of Childsplay.

After I finished my recent articles on Teaching with Tux and Learning with Gcompris, I received a couple of suggestions from readers that I take a look at Childsplay. I spent some time looking at Childsplay and if you have small children, I think you should too. As soon as I started the program, it started to play it’s theme song and my 18 month old son came running, and he still comes running every time he hears that music. For most parents and educators, my review of this program could end right here, but I suspect that I should probably write a bit more.

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Teacher turns “Crazy Idea” into new school

October 20, 2009
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Seen on CNN. The article.

"I started talking about 21st century skills and wanting to prepare our kids in math and science, especially our low-income and ethnic minority students," Ursetta said. "We’ve been doing schools the same way in this nation for 150 years, so if we don’t step up, then nothing is going to change." … She immediately started "pulling together a group of teachers to sit down with a blank sheet of paper and ask how you would do a school differently."

The main takeaway ideas seem to be: teacher autonomy, math-and-science focus. It’s kind of cool to see people working to revive the public school system.

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‘Reading Rainbow’ reaches its final chapter : NPR

September 2, 2009

File under: the mind is not a vessel to be filled but a fire to be kindled; the Kindle; and also that fabulous cover of the Reading Rainbow theme song by 8bit bEtty. Thanks Adam!

After 26 years, the beloved children’s show hosted by LeVar Burton will disappear from the airwaves. Today, educational funding favors programs that teach kids how to read, rather than why to read.


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A Functional I/O System (or Fun for Freshman Kids)

August 3, 2009

Seen on Lambda the Ultimate. The paper (PDF), the coverage.

If input and output were invisible, students could implement fun simulations, animations, and even interactive and distributed games all while using nothing more than plain mathematics.

I maintain that people don’t “think” in terms of plain mathematics, and teaching them along those lines is setting yourself up for disappointment, but there are some comments here that seem like they could be useful. Are loop invariants a thing I unconsciously abide by when I write loops? Hard to say.

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Software as an abstract gamespace that is not about software

June 23, 2009

The story from LWN:

Michael Dehaan muses about the future of open source software. “In the future 1000 years from now, was it more important to have worked on Web App X or Database Engine Y? Neither. Because that can’t be what matters. Theory: The power of OSS tech is not in technology, it is that it crosses boundaries. It is a system, an ideal. The tech does not matter. OSS is not about software. Software is an abstract playing field in which we teach ourselves how to collaborate. One of many such fields. Maybe not even the most efficient. Computer Science is just about logic anyway. It was never about computers.” (Thanks to Paul Wise)

Money quote: “There is still the question though, how do I choose what feature to work on tomorrow that improves the world the most?

Is the answer that it is not a feature, but instead, the question, how best can I help other people to help other people to help other people?”

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A Mathematician’s Lament –an Indictment of US Math Education

June 19, 2009

File under: the education system sucks, math is cool, being a nerd is awesome. The PDF is 25 pages, read at least the first four. The story on Slashdot:

Scott Aaronson recently had “A Mathematician’s Lament” [PDF], Paul Lockhardt’s indictment of K-12 math education in the US, pointed out to him and takes some time to examine the finer points. “Lockhardt says pretty much everything I’ve wanted to say about this subject since the age of twelve, and does so with the thunderous rage of an Old Testament prophet. If you like math, and more so if you think you don’t like math, I implore you to read his essay with every atom of my being. Which is not to say I don’t have a few quibbles […] In the end, Lockhardt’s lament is subversive, angry, and radical … but if you know anything about math and anything about K-12 ‘education’ (at least in the United States), I defy you to read and find a single sentence that isn’t permeated, suffused, soaked, and encrusted with truth.”

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The Manga Guide to Databases

May 4, 2009
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W.R.T. the link Adam posted a few days ago about how Computer Science would be more attractive if it focused on social ills comes this Slashdot review of the Manga Guide to Databases.

Princess Ruruna, of the Kingdom of Kod, has a problem. Her parents, the King and Queen, have left to travel abroad. Ruruna has been left to manage the nations fruit business. Much is at stake, Kod is known as “The Country of Fruit.” Ruruna is not happy though, as she is swamped by paperwork and information overload. A mysterious book, sent by her father, contains Tico the fairy. Tico, and the supernatural book are going to help Princess Ruruna solve her problems with the power of the database. This is the setting for all that takes place in The Manga Guide to Databases. If you are like me and learned things like normalization and set operations from a rather dry text book, you may be quite entertained by the contents of this book. If you would like to teach others about creating and using relational databases and you want it to be fun, this book may be exactly what you need.

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Socially Relevant Computing

April 30, 2009

Thanks Adam for the link. This is such a great point: many students want to study something with an impact.

The author argues that when intro computer science is taught using silly, simple examples, students just don’t see the potential power and relevance of the tool.  “Even… pure mathematics has me counting and measuring planets and populations.”  He’s created an alternative set of examples that are much more socially relevant, involving for example voting systems (counting), pollution in the great lakes (2-d arrays), disaster evacuation (optimal paths), and drug interactions (databases).

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