Archive for October, 2009

Old flame (attraction from the past)

Tuesday, October 6th, 2009

Attraction

I was digging around on the Wayback Machine today, and stumbled across a lost piece of code from December 2004. It’s a Strange Attractor Generator, from the pages of Clifford Pickover’s book Computers, Pattern, Chaos and Beauty (p 165).

As the equation wanders through its orbit, each pixel hit is darkened by a shade. This reveals the features in a way that would have been hidden by a simple drawing of the graph. The only addition I made (beyond introducing the code to Processing) was to enact this process over time, which makes for a lovely sense of a landscape etching its way into existence.

Click on the applet area to generate new, very different orbits. Pickover describes this well:

A “strange attractor” has an irregular unpredictable behaviour. Its behaviour can still be graphed, but the graph is much more complicated. With “tame” attractors, initially adjacent points stay together as they approach the attractor. With strange attractors, initially adjacent points eventually follow widely divergent trajectories. Like leaves in a turbulent stream, it is impossible to predict where the leaves will end up given their initial positions.”

The Wayback Machine is great for HTML docs, but many Java applets and Flash movies have disappeared, vanishing in the uniquely permanent way electronic media can. Processing, however, encourages the source code to be made available and distributed in the act of publishing. This meant the code could be copied and pasted, and run as if it were new.

Joining the queue

Monday, October 5th, 2009

Queue 1

Queues are comprised of customers joining, waiting and then being served. There are two random processes here: arrivals, and serving time, which in this case are both Poisson processes. There can be one or more servers. A handy notation for this is: M/M/n, where the first M describes customer arrival, the second M server processing time, and the n the number of servers.

In this applet, there are 150 queues, each one M/M/5, with a customer arrival rate \lambda of 20 per second, and a server rate \epsilon of 3 per second.

As each customer gets served, their dot turns red, and all the customers shuffle up one. When serving is finished, the dot disappears. As the server has become free, the next customer is served.

This first attempt demonstrates the variation that can occur. Currently, the queues move to the right if serving outpaces arrival. The next step is to have them wait at a particular point, and then moving off when a server is free, with those behind moving up to fill the space.

More queue models to follow, though not sure what their arrival rate will be…

Mnemosynr

Sunday, October 4th, 2009

You have a set of friends, colleagues and vague acquaintances you’ve accumulated over the years, and expressed as a graph of connections in various applications such as Facebook, Myspace, blog networks, twitter, flickr etc. You’ve spent years constructing a trail of digital detritus.

Mnemosynr lets you press a button, wipe your list of friends away, clears your office party pictures, deletes your thoughtful snaps of rolling hills from flickr, empties your blog of all those valuable observations.

Then it takes the mass of Facebook accounts, arbitrary images, occasional mutterings from twitter, and randomly chooses elements to recreate the whole construction.

You now have new friends, with a history of conversations, events attended, and a whole new list of old schoolfriends to ignore. Internet caches are rewritten, search engines reindex, reputations are recalculated. You have been digitally reconstructed.

As memories have long ago been discarded, to be replaced with paginated histories, the transition is painless.

Redecorated

Sunday, October 4th, 2009

I’ve had the builders in, and redesigned this blog. The main aim has been to make a bit more room. The default Wordpress theme, despite cosmetic adjustments, is a little mean and narrow – while the wide themes all have strange quirks in their efforts to look slick.

Blueprint made it easy to bash a gridded layout together, leaving me to spend time on the details. I borrowed Mark Boulton’s new fondness for Georgia, as the Helvetica/Verdana combination is a little austere for my ramblings. It’s strange how tastes change – a few years ago, I’d have thought  serif fonts were caused by a missing stylesheet. Now I feel it makes things look nice and textbook-like.

The little robot is back, waving about at the top right. I made him years ago, and he’s done a solid job in a time when digital presence is scattered round multiple sites.  He suffers from my occasional attacks of minimalism, but doesn’t do any harm. Not yet anyway. Let me know if he attacks.