Working on the 4th assignment of Formal Methods: an analysis of the bounded retransmission protocol. This is a protocol designed by Philips, used in remote controls for TV's.

We had 54 people playing today in the tournament. Ettie brought here digital camera (thanks!) I've made quite a lot of pictures but I haven't been able to connect the camera to my computer yet.


Hans Baert is this weekend's big winner: yesterday he won the worldcup qualifications in Weesp and today he was number 1 here in Haarlem! The other person who will play in Eindhoven is Frans de Bode, an honourable third place is for Harry Rood.

Ettie, Mieke and Jaap also participated.

Their results were quite good: both Mieke and Ettie were first in a game! In the final score Mieke was 24th, Ettie 25th. Jaap enjoyed the playing a lot.

Due to a broken alarm we're awake already -- it was 50 minutes ahead. At least we'll be on time for the tournament :)


Just heard that the demonstration will be in the same place as the tournament -- BC de Fjord, Paul Krugerkade 6.

We came back from a really nice game-demonstration. The shop we were in -boekhandel de Vries- is a big bookshop in the center of Haarlem. There were a lot of people coming in, and we explained many games.

I learned how to explain In De Ban Van de Ring today; I played it once with Jerry and Marjolein but that was a long time ago. We didn't bring the game ourselves, but a girl came by who asked if we could explain it. I told her I couldn't because we didn't have it, but then she went home and fetched her own.

Petra also came to see us; she played a game De Hobbit. After all this games we really want to play ourselves... so when Steven comes, he'll have no choice :)

Another game-weekend! Tomorrow there'll be a demonstration, Sunday both a tournament and demo. And Monday we'll see Marjolein & Jerry for a Steden & Ridders.


Sasha and I will be working both days, it's all here in Haarlem! So we don't have to leave at 7:00 (like when we left for Amersfoort or Leeuwarden). Ettie and my parents will play on Sunday.
There's also a third event, the WK qualifications in Weesp. Rob and Jerry will do that one.

Saturday:

Boekhandel de Vries, Gedempte Oude Gracht 27

Sunday:

Paul Krugerkade 6, Haarlem (tournament)

Game Time, Gen. Cronjéstraat 47 (demo)

Google is celebrating it's 4th anniversary today.

They are now the most popular search engine on the web, and still growing in popularity. A feature they are currently testing is their news website, a digest of about 4000 news sources. The cool thing is that it's generated automatically, without any human intervention.

Yesterday evening I've installed an e-mail server on guusbosman.nl. So I should be able to receive e-mail at www1002@guusbosman.nl from now.


If you could try it: please do. We're still thinking about which movie to see tonight, so suggestions are very welcome!

Okay, okay... I'm at work now but I just couldn't help noticing this interesting article on CNN.com.


There will be a sex-museum in New York! Big news of course. The museum in Amsterdam is also briefly mentioned.

I've been working on the 3rd assignment of Formal Methods today.

The assignments basically involve describing various systems in a formal language, and then generating a state-space of it. There are a number of tricks to reduce this state-space, while some properties will still hold. This way it's easy to prove certain behaviour.

In the assignment I did today (not quite finished yet), the goal is to prove that the alternating-bit protocol is a good protocol. That is, that a bit put in from one side will come out from the other one (even though the channels might be unreliable). After reduction of the original state-space (left), only 3 states remain: 0 (nothing going on), 1 (a 1 is sent and received) and 2 (a 0 is sent and received). The thing we proved this way is that there is no 'state 3' in which for example a 1 is sent and a 0 received (this would be an error).


Tomorrow I'll go to Chess and continue there because I want to print a few of the state-spaces. This to help me understand exactly how the state-space reduction algorithms work.

He's on the bus, it takes about 26 hours before he's in Hungary...