Monthly Archives: February 2008

Telescope on the dark side of the moon

The 60-Second Science podcast from February 27, 2008 tells of plans for NASA and MIT to build a giant radio telescope on the dark side of the moon. (The “dark” side is really the “far” side, the side that always

Tagged with:
Posted in Science

What to make "u" in integration by parts

Integration by parts says The first question students ask is What do I make ‘u’ and what do I make ‘dv’? I used to tell my students to set ‘u’ equal to the part you’d rather differentiate and ‘dv’ equal

Tagged with: ,
Posted in Math

Confusion

One of my professors once told me that you learn the fastest when you’re slightly confused. If you’re too confused, you’re likely to give up in frustration. But if you’re not confused at all, you’re either not learning or learning very slowly.

Tagged with:
Posted in Creativity

What a probability means

My daughters and I went to a CoinStar machine last night to convert a huge bowl of change into an Amazon gift card. The question came up of the probability of the total coming out an even dollar amount. My

Tagged with:
Posted in Statistics

Code to make an XML sitemap

Here’s some Python code to create a sitemap in the format specified by sitemaps.org and read by search engines. Download the file sitemapmaker.txt and change the extension from .txt to .py. Change the url variable in the script before running

Tagged with: , , ,
Posted in Computing, Python

Everything begins with "p"

There’s only one symbol in statistics, “p”. The same variable represents everything. You just get used to it and figure out which p is which from context. It reminds me of George Forman naming all five of his sons George. Here’s

Tagged with:
Posted in Statistics

Sample code sites

Here are two sites with sample code in dozens of programming languages. PLEAC (Programming Language Examples Alike Cookbook) takes the Perl Cookbook as its template and implements the examples in 25 languages. Some languages are more complete than others. For example,

Tagged with:
Posted in Python, Software development

International lunar exploration

The February 20th Science at NASA podcast gives a brief overview of the upcoming lunar exploration efforts by China, Japan, India, Russia, and the United States. Within four years there could be nine satellites orbiting the moon. The podcast site has

Tagged with:
Posted in Science

Technical papers posted

I added two technical articles to my personal web site this evening. Step size for numerical differential equations is a one-page set of notes on how to select the optimal step size when numerically solving ODEs (ordinary differential equations). Separation of convex

Tagged with:
Posted in Math

OpenDNS

Phil Windley recently released a podcast about OpenDNS. My first thought was to wonder why anyone would want to tweak their DNS, except for the most sophisticated users. But in some ways, the least sophisticated users have the most to gain from

Posted in Computing

Periodic table of Perl operators

Mark Lentczner has posted a periodic table of Perl operators. The table shows Perl 6 in all its Byzantine glory. If you work in the language constantly and enjoy the terse syntax optimized for experts, you’ll love Perl 6. But if you’re

Tagged with: ,
Posted in Software development

Probability distribution relationships

In 1986, Lawrence Leemis published a paper containing a diagram of 43 probability distribution families. The diagram summaries connections between the distributions with arrows: chi-squared is a special case of gamma, Poisson is a limiting case of binomials, the ratio

Tagged with: ,
Posted in Math, Statistics

Free bitmap to vector format software

VectorMagic is a free online tool from the Standford University AI lab for converting bitmap images to vector formats. The image below shows an example of what you might use this tool for. I just heard about the software and tried

Tagged with:
Posted in Graphics

What to make flexible

In the book Universal Principles of Design by William Lidwell, Kritina Holden, and Jill Butler, the authors have this to say about the flexibility-usability trade-off. It is a common assumption that designs should always be made as flexible as possible. However, flexibility

Tagged with:
Posted in Creativity

Why programmers cannot be managed

Interaction design guru Alan Cooper gave a presentation recently entitled An Insurgency of Quality. As part of his talk, he explains why programmers cannot be managed. Traditional management has an industrial age mindset, while software development is a post-industrial craft.

Tagged with: ,
Posted in Business, Software development