Jason Underdown’s Blog

I stumbled upon a short but useful introduction to emacs on the web. It has lots of screenshots to demonstrate the different commands. It even touches upon development tools like gdb and diff.

Free Software Magazine has an excellent article on how to Run any GNU/Linux app on Windows without any virtualization.

It explains how to install, setup and use the free Xming X Window server for Windows and also how to use SSH from the command line. It also includes information on how to enable SSH access into an Ubuntu machine.

This code generates fractals based upon an iterated function system (IFS). Several input files and a Makefile are included. The code is written in C++, and distributed as a tarball. I did this for a class at the University of Utah, but it is based upon a homework assignment for a computer graphics class at MIT (6.837).

Below is the famous Barnsley fern which was generated by an IFS with just four transforms!

The New York Times has an excellent op-ed piece today on college admissions. Read the article, and you’ll see why test prep centers like Kaplan are doing so well.

Joel Spolsky has an excellent essay on his blog about AJAX web apps and where they’re headed. The essay is entitled Strategy Letter VI – Joel on Software and I highly recommend it!

I used to be very enthusiastic about a startup that originated at MIT called Curl Corporation that did much of what Joel talks about with one major exception, instead of targeting JavaScript, they targeted their own runtime. Now that has the major disadvantage that users must download the runtime in order to run client-side Curl code, but the widespread adoption of Flash (which sucks in comparison because it was designed for visual effects) leads me to believe that if they had decided to freely distribute their runtime (for commercial as well as non-commercial use), then they would be rulers of the web by now. Their language is fairly Lispy like Joel talks about in his essay, and was a joy to use, but alas, they decided to take the short-term route and market their technology to large corporations for intranet applications. I tend to think that if they had taken the long-term strategy of targeting the entire web, then we would all be using Curl now and enjoying very rich client-side web apps instead of bickering about how to best AJAXify your web-site/application.

At this point in time, I think Joel is spot-on about the need to target JavaScript, instead of creating a new runtime, because that avoids the chicken and egg dilemma. But the devil is in the details. It may be a considerable challenge to seamlessly target Microsoft’s, Apple’s and Mozilla’s JavaScript engines.

I found this article in today’s New York Times to be very fascinating:
The Subconcious Brain – Who’s Minding the Mind?

Michael Peskin recently posted an article to the arxiv entitled “Dark Matter and Particle Physics”. The article is an almost layman’s guide to how the WIMP model of dark matter might soon be partially validated experimentally at the LHC.

In the article he outlines the reasons why most matter in the universe is dark or in other words does not emit light or radiation, and thus is normally only detected via its gravitational effects. He then goes on to describe the WIMP model for dark matter and its predictions. Next he talks about how the LHC might detect WIMPs:

The discovery of events at the LHC with apparent unbalanced momentum will signal that this accelerator is producing weakly interacting massive particles. However, it would be far from clear that this particle is the same one that is the dominant form of matter in the universe. To demonstrate this, we would need to correlate properties of the WIMP that we observe at the LHC with astrophysical observations.

There are two possible ways to observe WIMPs outside of the LHC. First is the direct approach of observing the scattering of a WIMP from a nucleus in an extremely sensitive detector located deep underground in a mine to minimize noise. The second method is to observe gamma rays emitted from pairs of WIMPS annihilating each other. These gamma rays should have a characteristic spectrum and be most commonly found coming from parts of our galaxy where the concentration of dark matter is highest, namely near the center of the Milky Way.

If the mass of the WIMP seen at the LHC is the same as the mass from astrophysical detection experiments, this will provide strong evidence that the LHC is producing the true particle of dark matter.

Thanks to Hwasung “Mars” Lee for pointing out this article in his blog.

If you would like a great summary of differences between versions 2 and 3 of the GPL check out Mark Radcliffe’s blog post: General Public License Version 3: A Legal View on his blog entitled Law & Life: Silicon Valley.

I added an RSS feed to update anyone interested on changes I’ve made to my Math and Physics flash cards page.

In my last post, I mentioned that I had created some flash cards for Real Analysis that had definitions on them. I recently created a set with many of the relevant theorems, and I will be updating them as the summer progresses. Thanks to Erin Chamberlain for providing the source TeX code for the theorems. You can find them at

http://www.physics.utah.edu/~jasonu/flash-cards/

Enjoy!

I’ve been busy this summer studying Real Analysis, and in the process I’ve made a set of printable flash cards in PDF format. They’re still a work in progress, but I have over 90 cards full of definitions. Cards with theorems on them will probably come some time later. The pictures below show what the typical front and back of a card look like.

I was just reading an article on the New York Times entitled “Science of the Soul? ‘I Think, Therefore I Am’ Is Losing Force” and while reading I came across the word “palaver” in the text. Not knowing its meaning I double clicked on it to highlight it so I could easily paste it into Ubuntu’s dictionary, but there was no need. The website popped open a window with the definition for me. Pretty cool! I wonder how long this has been working?

I have an RSS feed from Boing Boing on my Google home page, and today they have a posting about University of Utah physics professor Orest Symko! The post describes his research into turning waste heat into electricity via an intermediary acoustic step.

It seems to me that the solar updraft tower might be a good match for this technology.

I’ve been a big fan of Dilbert for years now, but I recently found a great webcomic that I’ve started reading daily called XKCD. The tagline is: A webcomic of romance, sarcasm, math, and language. The drawings are simple stick figures, but it is the situations and ideas that are interesting and funny.

While googling for information on the Virial Theorem, I ran across a really cool page hosted at the Harvard ADS system. ADS stands for Astrophysics Data System, and it is primarily an abstract search engine that helps you locate journal articles mostly in the realm of Astronomy and Astrophysics, but they also have a small virtual library of books that you can freely download.

Here are the titles I found interesting:

• The Foundations of Celestial Mechanics by George W. Collins, II
  (1989, 2004).
• The Fundamentals of Stellar Astrophysics, by George W. Collins, II
  (1989, 2003).
• Fundamental Numerical Methods and Data Analysis by George W. Collins, II
  (1990, 2003).
• The Virial Theorem in Stellar Astrophysics, by George W. Collins, II
  (1978, Pachart Publishing House, Tuscon, Arizona).

If you want to concatenate all the separate PDF chapters, I recommend using the texexec method oulined in this web page by Matthew Skala.

The above picture links to a good blog article about why DRM won’t succeed.

I found a link via Marcus Woo’s blog to a superb set of videotaped lectures by Richard Feynman on Quantum Electrodynamics or QED. He masterfully describes the basics of quantum mechanics at the layman’s level. I’ve only watched the first video completely through, but I was very impressed with the clarity with which he explained the subject. The video requires the Real Player.

I’ve created a new deck of flash cards for calculus. They cover high-school and college-level Calculus I, that is functions, limits, continuity, derivatives, and differentiability.

I also updated my Abstract Algebra flash cards to cover most all of elementary group theory. You can find my PDF flash cards at my web site:

http://www.physics.utah.edu/~jasonu/flashcards/

I found an interesting link on Phil Windley’s blog to a tutorial on programming in Haskell. This tutorial is different from most because instead of showing you small examples related to various language constructs, this one takes you step by step through the entire process of creating a Scheme interpreter. Seems well done.

Physicists George Smoot and John Mather won the 2006 Nobel Prize in physics for their work in analyzing the cosmic microwave background radiation, work that helped to support theories about the Big Bang. You can learn about their work on NPR’s Science Friday podcast.