I travel quite a bit, mainly on business (c.f. my C.V. on top of this page). See where I've been to the past few years.

The worldwide air transportation network: Anomalous centrality, community structure, and cities' global roles (Proceedings of the National Academy of Sciences, May 31/2005, vol. 102, no. 22, pp 7794-7799) is a research article I co-authored.

From the abstract: We analyze the global structure of the worldwide air transportation network, a critical infrastructure with an enormous impact on local, national, and international economies. We find that the worldwide air transportation network is a scale-free small-world network. In contrast to the prediction of scale-free network models, however, we find that the most connected cities are not necessarily the most central, resulting in anomalous values of the centrality. We demonstrate that these anomalies arise because of the multicommunity structure of the network. We identify the communities in the air transportation network and show that the community structure cannot be explained solely based on geographical constraints and that geopolitical considerations have to be taken into account. We identify each city's global role based on its pattern of intercommunity and intracommunity connections, which enables us to obtain scale-specific representations of the network.

This interactive Web application is a visualization of the international passenger air traffic network. You can select one or more cities from a list of approx. 3800 cities in the world, and the application will then show you all flights originating from those cities on a zoomable world map. [More...]

Requirements: This application uses technology proprietary to Microsoft, and it is heavy on resources on your machine. In particular, you will need

• Microsoft Internet Explorer 5.0, or later
• A fast processor, say Pentium II, or later
• Plenty of memory (64MB+?)

Note: Clicking on the link on the left will open a new window, 800 by 600 Pixels in size. The source file is 1.5MB large and may take a while to download. Also, once the file is loaded, depending on the speed of your CPU and the amount of free memory you have, you may notice a delay of a few seconds up to a few minutes depending on the selection criteria entered until the Web page gets rendered.

I have been working for quite a while on finding closed, simple expressions for primitive roots of unity, that is finding solutions of cyclotomic polynomials by radical expressions in the case of constructible regular polygons. The goal is to find solutions for the 5th, 17th, 257th, and 65537th root of unity. This is an onging project.

C#.NET Web Developer's Guide (Syngress Publishing) is a book I co-authored.

From the back cover: C#.NET Web Developer's Guide C# will teach Web developers to quickly and easily build solutions for the Microsoft .NET platform. Web developers will learn to use C# components to build Web services and applications that are available across the Internet, from any application running on any platform.

AIL—Instant Logger is an application that conveniently records all your Instant Messenger conversations. Works with AOL and Netscape Instant Messengers. Runs on all Windows systems.

6/2004: This project is now obsolete due to changed IM versions.

Load Birgit Vanderbeke: Fehlende Teile (German original; excerpt)

I "discovered" Birgit Vanderbeke in late summer 2000 while traveling in Europe. She is a member of a younger generation of German writers; born 1956 in Dahme, she lives in Frankfurt/Main and in the "south of France" (whatever that means).
Her stories are maybe not very heavy on plot, but she has an amazing handle on language. Her ability to work with words and phrases in innovative ways is maybe the main reason I quickly got very fond of her. Books of hers I read include Das Muschelessen (1990) (The Oyster Dinner), Gut Genug (1993) (Good Enough), Ich Sehe Was, Was Du Nicht Siehst (1999) (Twenty Questions), and Fehlende Teile (1992) (Missing Pieces).
The fact that her prose is tied so closely to the German language may explain why she has so far not been translated into English. I have attempted to translate an excerpt of one of her stories, focusing on keeping the original flow of the story intact as much as possible. Please note that this translation has not been authorized by the author.

A look at a large part of the IPv4 address space, this application offers a view of all class A (1.0.0.0 through 127.0.0.0) and class B (128.1.0.0 through 191.255.0.0) networks in the form of both a set of static HTML tables, and a downloadable complete list.

A single player Java puzzle applet with source code.