Sunday, May 29, 2011

Weighted Random Selection in Python

This morning I was looking for a Python implementation of weighted random selection, i.e., I have a set of weighted items and I want to randomly select one where the probability of selecting each item is proportional to its weight.  I found this blog post by Eli Bendersky which exposes a set of approaches nicely.

Friday, May 27, 2011

New Redshift Record of 9.4

Gamma ray observations of the gamma ray burst object GRB 090429B supplemented by infrared observations from the Gemini North telescope and United Kingdom Infra Red Telescope, both on Mauna Kea, place the object at a redshift of z=9.4, as reported by Emily Baldwin at Astronomy Now.  (Also at Cosmos by Miles Gough).

In the cosmological model, that would mean the scale of the universe was 9.6% of it's current size at the time the gamma rays and IR were emitted.    (1 / z + 1).

Also, see:  Cosmological Distances and Gains of Salt

Image credit: Gemini Observatory / AURA / Levan, Tanvir, Cucchiara.

Monday, May 23, 2011

Google Social Puzzle Pieces

By David Goldman at CNN Money.

Change Your Facebook Password

Access to your account may have leaked.  This discovered problem means it's been possible for others to access your account since 2007 via third-party applications.

The best thing to do is change your password as soon as possible.  That will invalidate any leaked tokens if they were in the possession of any evil doers.

More information is in this article at Symantec.

This is also explained in this installment of Security Now.  Skip ahead to the 58-minute mark.

P.S.  Note that you will have to enter your new password to third party apps you're using after doing this.  For example, on my Android phone I cleared the data and entered my email address and new password into the Facebook app.

Saturday, May 21, 2011

Cicadas Attack!

Well, I've experienced the 13-year cicadas that I've heard so much about. In Middle Georgia yesterday as soon as I opened the car door I was greeted by an almost deafening, hard to describe sound coming from the trees. It sounded like the summer cicadas I've always known, but louder and sharper.

They also filled the air. You could look up and see them constantly criss crossing the sky. Two or three flew into my face and hair.

It seemed like they'd taken up residence in every tree and bush in sight, but the rumors of the bugs eating every bit of vegetation in sight turned out to be unfounded.

Friday, May 20, 2011

Dark Energy Is Driving Universe Apart

NASA's Galaxy Evolution Explorer Finds Dark Energy Repulsive from Science Daily.

The findings offer new support for the favored theory of how dark energy works -- as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein's concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances.

Thursday, May 19, 2011

The First Hour or Two with the Cr-48

So, I've been using this ChromeOS notebook for a couple or three hours now.  Most things work fine.  I've done the usual email and documents work in Gmail, made a couple of phone calls using Google Voice in Gmail, and played a couple of screens of Angry Birds.

Right now I'm listing to music on Amazon Cloud Player.

Connecting to wifi was very simple.

Mouse motion, famously problematic on this hardware, was a little flaky when trying to play Angry Birds, but otherwise I don't notice much problem.  I finally found the check box to enable tap to click, so that is all better now.

I found the terminal with ssh via Ctl-Alt-T and tried it out.  It works but, again, wide-screen insanity prevails.  Also the font and colors need to be fixed in the terminal.   It's a limited set of commands but ssh is really all I'd need.

Right now it's on the charger and has charged up to 78%.

Wednesday, May 18, 2011

Using a Cr-48

This is my first blog post and my first user session with a Cr-48 running ChromeOS.

Everything is great so far except for one thing:   The windows are all full screen.  That's about the most annoying thing I could think of.

Otherwise, everything is working pretty well with almost no problems.  I like the size, form factor, weight and even the keyboard so far.

Oh: A Shell Written in Go

By Michael Macinnis.  README at Github.

Tidal Energy In the UK

Fascinating.  They have tidal energy generators in the UK as reported by this article by Chris Goodall in The Guardian.  I find it amusing that they call the energy “renewable” when it's really depleating the angular momentum of the earth's rotation and the moon's orbit.

Still, as far as I can tell, renewable always means a big enough supply that we can't imagine when we'll run out. That's the way new energy supplies often start out.

Saturday, May 14, 2011

Tuesday, May 10, 2011

Projection on 26-Story Coca-Cola Building

For it's 125th anniversary, Obscura Digital arranged to turn Coca-Cola's 26-story headquarters building in Atlanta into a giant, four-way projection screen.

The show
About the show
Article from The Street
Obscura Digital

From The Street:
The entire Coca-Cola North Ave. tower in Atlanta—26 stories high and 402 feet (122.8 m) high—is canvassed in scrim.

The projection covers an area 339 feet high and 157 feet wide per side of the building.  The projection surface area from all four sides of the building totals more than 210,000 square feet, making it the world’s largest single building illumination. 
This display uses 45 projectors that are 20,000 lumens each, for a total of nearly 1 million lumens of light simultaneously projected onto the building.  The overall projection resolution is more than 7,000 pixels wide (7040 x 3800).

Friday, May 06, 2011

Paper Computers

I remember an interview with someone from Xerox PARC, probably almost 30 years ago, where they were talking about ubiquitous computers that were like paper.   I remember a quote that went something like, You'd just tear a new computer off a pad when you needed one.  They'd just be laying around your office in piles.

Well, they seem to be here, as reported in this article in The Economic Times.

Thursday, May 05, 2011

Saturday 2011-05-07 Is National Astronomy Day

There are events planned at Fernbank and Tellus.

Cloud Computing

Seth asked about our sightings of and thoughts on cool, emerging technologies.

I continue to hold that the technology that promises one of the most significant impacts is cloud computing.  It's been coming for a long time but cloud computing has recently turned one of those corners and it's influence is rapidly accelerating.

Basically, cloud computing means that your data and your applications are out on the Internet, “in the cloud” as we say.

I've been moving my own work into the cloud and I'm probably following that acceleration curve pretty closely.  Here's my current score card.

I've been a user of web-based email since Rocketmail and Yahoo's re-branding and evolution of the same when they both took off around 1997.  For years I merely echoed email into the cloud, keeping my own personal copies on an email server at home.  Sometime around the introduction of Gmail, I stopped keeping my own copy and  switched wholesale to Gmail.

I've been using Google Documents in earnest since 2006.  Since then, probably 99% or more of every document or spreadsheet I've created, including home and work, have been in the cloud.  I added slide presentations to that in 2007, and drawings most recently.  (Note that I've still not found a replacement for Windows Paint, though).

In 2006 I moved my blogging off of my own server and back to Blogger and Blogspot.

For the past several years I've been putting more and more pictures in Picasa, though it's not my sole storage medium in that category.

In the fall of 2009 I became a user of GTD and moved my next action lists and projects to Gmail Tasks.

Over this past year, my move into the cloud has gone mad.

I've used Piknic solely for photo editing.

I've migrated all of my note-taking into Google Documents.  Many folks will remember the blue notebooks I used years ago, inspired by my old friend Leonard's use of them for journals when we were at Georgia Tech.  For a number of intervening years I moved most of my note-taking into on-line text documents edited with Emacs.  Over this past year I've migrated almost 100% of my note-taking on-line into Google  Documents.  I create several new documents every day.

Also this year I made the conscious decision to start migrating all of my media consumption into the cloud and at the same time, decided to get a Roku box instead of a Blueray player.  I use Netflix and Amazon, and occasionally Dish on Demand, for movies, Kindle for books, and Amazon, Pandora and Slacker for music.  My thought is to never again purchase physical media.

I've moved most of my own little command-line utilities into AppEngine equivalents.

I've also become a recent user of Dropbox for file sharing.

The personal Linux “main machine” that I use at work for programming has been a virtual machine for the recent few months.  The next (final?) frontier, for which I'm waiting with poised fascination, is a browser-based integrated development environment for writing, testing and running the computer programs I write daily.  A lot of work is underway and there are some initial results out there now.

I'm late to this ballgame, but I'm also getting ready to move my backups to Carbonite.  That will probably be another case of just putting a copy there, while maintaining other current schemes.

I'm already at the point that I can do almost any thing of significance I do on a computer from any computer that I truly trust.

Dark Matter Valliantly Holds On

In it's flight to remain dark but Jennifer Ouellette says the debate is heating up in this analysis at Discovery News.

Image credit: Computer simulation of large scale structure from Science Magazine.

Wednesday, May 04, 2011

Finally, the Voice of Reason Regarding Aid to Japan

From The Economist article After the Quake.

From the article:
What you shouldn't do is give money to charities that are raising money off the disaster. The New York Times' Stephanie Strom explained why last month:

[W]ealthy Japan is not impoverished Haiti. And many groups are raising money without really knowing how it will be spent — or even if it will be needed. The Japanese Red Cross, for example, has said repeatedly since the day after the earthquake that it does not want or need outside assistance. But that has not stopped the American Red Cross from raising [tens of millions of dollars] in the name of Japan’s disaster victims.

Tuesday, May 03, 2011

Monday, May 02, 2011

Facebook credits

A 600 million-dollar virtual economy (from  Yikes!

Why Apple and Google Need to Stalk You


Chitty Chitty Bang Bang

Is up for sale as reported by Gizmodo.

More information is at Profiles in History.

Built on a custom ladder frame chassis, many old world forms of car building were employed, and modern technology stepped in to created a vehicle which was both accurate enough to fool veteran and classic car experts, when held under the scrutiny of 70mm cinema cameras, and durable enough to withstand everything from driving in sand, cobbled streets and down staircases. The bonnet is crafted of polished aluminum; the boat deck is hand-crafted of red and white cedar built by boat builders in Buckinghamshire, and the array of brass fittings were obtained from Edwardian cars. Even the alloy dashboard plate is from a British World War I fighter plane!

Most powerful millimeter-scale energy harvester generates electricity from vibrations

From  This is fascinating.

Watch This Impressive Forerunner Of The iPad From 1994

[VIDEO] From Business Insider.

Usefulness of Inventing Programming Languages

Emilis Dambauskas invents a programming language using bullet lists.

Catching Up

Okay, time to catch up again to empty some items I emailed to myself into the blog.