Archive for January, 2007

Wallpaper Roundup

Sunday, January 28th, 2007

Here’s a quick roundup of wallpapers or images that are so cool you must use them as wallpapers. Almost all of them can be found at Included are some nice freehand drawing pieces, somewhat girlish but beautiful vector art, photos and manipulated photos and nice science fiction space stuff.

Red Leap - Wallpaper by `dinyctis Celestial Light - Big by ~Eclipse-CJ3 Life by ~Telefunken123 The Gang - Wallpaper by *TinyPilot Screams Characters - Wallpaper by *TinyPilot wallversion Dreams can be real by ~wow-dg A trip to wonderland by ~secroit Fluid Motion Wallpaper by =ka05 AquaFireing Mode 03 by ~donzee 2007 by =Aurelia24 Cosmic Sunrise by `dinyctis Earth at night

Furthermore, cool high-resolution wide screen wallpapers can be found here. A wallpaper search tool that searches the best photo sharing service in the world is wallpapr. A good resource when looking for nice wallpapers is also this page. However, nothing beats

Visualization of Social Network

Sunday, January 21st, 2007

Update: I created a tool to convert CSV files to Walrus compatible LibSea files. Check out walruscvs here You can find additional social network visualizations here.

For a long time now I have been a great admirer of Matthew Hurst’s work and I’m continuously impressed by the works posted at So I decided it was time for me to try something like this myself.

Visualization of large Social Network

What I did is write a program that is able to log in to a very popular German Social Networking website and grab some data from it. I grabbed the friends of my profile (only 2) their friends (about 100) and the friends of their friends (about 5000). I used PHP with cURL for that and saved the data to a MySQL database.

Visualization of large Social Network

Then I looked for tools to visualize the data. Turns out it’s quite hard to find something suitable. Here’s an (incomplete) list of tools one can choose from. Ultimately I ended up using Pajek and Walrus.

The results I got from Pajek were a bit disappointing as the network creation algorithm does not seem to work that well on very large (>5000) nodes and it is unable to render images that emphasize a 3D feeling (so no eye candy):

Chaotic Visualization of large Social Network

However I was able to create two videos of the networks I rendered. Check out video1 here, a visualization of a very small network, and video2, which shows the entire network.

The results I got with Walrus where definitely better. It was quite complicated to get Walrus to accept my data as it heavily relies on a spanning tree, but I managed to get it to work:

Visualization of large Social Network with Walrus Visualization of large Social Network with Walrus

I also was able to create a video of the network I rendered with Walrus, check it out here.

My work of course is not as sophisticated as the items mentioned at the beginning but I still like some of my graphs.

Google – the data octopus

Sunday, January 14th, 2007

Google - the data octopus

Although this post shall be mainly about Google, I will start with another example: Amazon. If you bought a few times at Amazon, you will notice something when you visit their website. They give you recommendations on what to buy next. And most of the time this recommendations are pretty good, most of the time you would really like to own one of the products they recommend.

And probably everyone nowadays knows how they do it. They track everything a user does, from simple browsing, over searches to purchases and put together a profile of each customer or visitor. They compile a really huge database out of this pieces of information. And then they link this pieces together. The process is called “Data Mining“.

An Example: with the help of fancy algorithms and statistical analysis techniques they discover: 100 people bought the latest album by “The Killers”. 15% of those people also bought the latest album by “The Strokes”. So they reason if you bought the latest Storkes album you might also be interested in the Killers album.

This is of course only a very simple example as it only includes 2 features. Considering how many visitors, purchases and products Amazon has.. well. The data they have at their disposal should be quite good. By now they have probably a profile of every single one of us. Although you never bought anything at Amazon, your profile might just be in their database. Humans are not so different.

And what about Google? Do they create profiles of their users too? Hell yes. And the data they can gather from their users might be even better. Here’s a (incomplete) list of services Google offers and my ideas of what data they could gather from that.

  • Search:
    They analyse the keywords you type in, the search results you click and the sponsored links (ads) you click upon. They get a really huge profile of your search habits if you use the Personalized Search Service. Also if you have a personalized homepage all keywords may be tracked back to you.
  • Gmail:
    Obviously: they scan your e-mails for keywords to put together ads. They can get a pretty good idea of what you’re interested in and of what you’re doing by reading your e-mail.
  • Personalized Homepage:
    They know what gadgets you include in your personalized homepage. This also gives them a pointer on what you are interested in. Are you a software developer, politically interested, interested in finances, are you a democrat or a conservative? They may find that out.
  • Google Reader:
    They know: what feeds you like, how regularly you read the feeds, what feeds you read most, how much time you spend reading newsfeeds. And they make no secret of it: Check out this article from their blog.
  • Google Talk:
    That in conjunction with Gmail is their greatest source for social information. They know who you’re friends with! They also know how much time you spend in front of your computer.
  • Google Groups and Blogger:
    They know what topics you’re interested in in terms of newsgroup discussions or blog comments (if the blog you comment on is hosted by Blogger).

Now don’t get me wrong. I’m not a fanatic Google hater. As a matter of fact I use some of the mentioned products myself (including Gmail which is probably the worst in terms of privacy) however I think it’s important for people to be aware of what can be done with their data. And yes, I’m aware of the irony that this blog is powered by Blogger.

Flickr Photostream Plugin

Sunday, January 7th, 2007

Finally there was time to complete the Flickr photostream plugin for the blog. It’s a script that fetches the three most recently added images from a special flickr photoset.

It makes use of the ingenious Javascript library, which is based upon the fantastic Prototype framework. For the XML parsing of the Flickr output I used this tutorial here. Quick and dirty but working. To create the shaded borders I heavily depended on this nice tutorial.

As I feel like sharing, the PHP file can be found here. It will not work for you out of the box as I am making heavy use of CSS in the output. For the script to work correctly the library also has to be included into the webpage.