nothing clever

moving ...

I've had enough of phpsimpleblog and made what I hope is a step up in life and moved this blog to http://gromgull.net/blog and a wordpress installation.

Go there and subscribe to the new RSS feed!

This will remain here for the time being, although all the posts (but not comments) have been moved to the new blog as well.

Two Organik fools in front of a whiteboard

Recently we realised that not all partners in our Organik Project shared the same vision of what we were trying to do. When we tried to write this down to share it, we found that we didn't really know what was going one either, and a quick discussion with the white-board sorted it out. Then we realised that watching us fighting it out in front of a whiteboard is probably much more entertaining than reading some dry document, so we did re-enacted it in front of a camera, and here it is for your viewing pleasure:

GPS Geekery

At the weekend we drove from Kaiserslautern to K�ln and back, and I used the OpenMoko FreeRunner as a GPS tracker on the way. It worked impressingly well, it got a fix in about a minute happily tracked for nearly 6 hours without charging the battery. The TangoGPS logging left me with a text-file with about 10500 entries of gps coordinates, speed, heading and time. TangoGPS is great on the openmoko, but it's not very feature rich when it comes to looking at the logs later. You can load them, and see them on the map, but that's it.
There is a tool called gpsbabel which can convert these logs to other formats for GPS logs, and this let me convert my logs to .kmz files and again view them, now in Google Earth. However, what I really wanted was a bit more analysis, at least giving me average speed, etc. Mainly I was looking for an explanation why the car used more petrol on the way home than going out.
A quick googling brought me nothing, so I brought out R, which I've not really touched since finished the PhD. The syntax of R really hasn't improved since last time, it still feels like it's cobbled together by very talented and intelligent people, but people who never saw a real programming language before. Anyway, R had a bit of trouble plotting the 10,000 data points, at least quickly enough for my taste. To reduce the data I learned a new '''awk''' trick, and '''cut''' that I discovered last week:



cat tangogps.log | awk 'NR % 4 == 1' | cut -d, -f 4,7

This will print only every 4 lines, and only the speed and date. (In retrospect it would perhaps have been much easier to do this in R). Now finally, loading it into R I could find out that my average speed was 22 km/h. I couldn't quite stop there though, so I spent nearly an hour plotting some things:

Speed driving from Kaiserslautern to K�ln:

(Note the 45 minutes spent standing still at the end because of damn FCK playing on Friday night)

Driving speed histogram:

And for completeness, the other way:

In the end I learned nothing, I drove slightly faster going there, so I should have used more petrol that way. Perhaps the head wind was stronger going back? A shame Kaiserslautern is south of K�ln, otherwise the explanation would of course be that driving 'downhill' uses less petrol...

Now this is perhaps getting a bit too geeky ��even for me.

Dopplr Travel Report

Kasei beat me to it, but Dopplr has released their yearly personalised travel reports. They are beautifully assembled PDFs with Flickr photos from selected locations and interesting facts.

It reminds me of the Feltron report, but saves me going through the hassle of collecting this information for myself.
I do like having personal data-sets available, and I often start collecting something, but quickly slack off and forget.

The Doomed Discipline

After introducing the attempts at making computers and software manageable Dijkstra says:

[...] A number of these phenomena have been bundled under the name "Software Engineering". As economics is known as "The Miserable Science", software engineering should be known as "The Doomed Discipline", doomed because it cannot even approach its goal since its goal is self-contradictory. Software engineering, of course, presents itself as another worthy cause, but that is eyewash: if you carefully read its literature and analyse what its devotees actually do, you will discover that software engineering has accepted as its charter "How to program if you cannot.".

From (E1036) On the cruelty of really teaching computer science

Exhilarating Acceleration

Now that the Nepomuk review is finished I've had some time to play with the OpenMoko FreeRunner. The state of the standard phone-software is abysmal, but the hard-ware is cool AND it runs python :) Since Kaiserslautern was covered in snow this weekend and it was not so tempting to go out I spent a few hours playing with the accelerometers. The actual idea for what to do started with seeing this screenshot:

of the game Zing on OneMoreLevel.com. The game is nothing like I thought it was, I imagined the small things to be very abstract cars and not bugs trying to eat you. Oh well.

Anyway, within a few hours and some ~~stealing~~ Creative Commons content later I had a crappy car game:

controlled by the accelerometer of the FreeRunner, i.e. lie the FreeRunner flat, start the game, now when you tilt the FreeRunner in some direction the car drives that way! Trust me, the scrreenshot really does not do it justice, the feeling you get frome the immediate control and the amazing sound-effects is... well pretty much just like driving in real life!

Download tarball, untar on FreeRunner, make sure you have python-pygame and libpng3 installed and run python car.py. Press AUX to exit. The code is of course not pretty, but does at least show some basics of Accelerometer handling.

End-user Requirement Analysis

I often refer to this one Dilbert comic, but I can never find it. Today I spent the time googling and found it using google book search. Now archived here for future reference:

Akademy 2008

Yay for regular blogging - last post was four months ago and that was from matthias who guessed my password :) - now I've found that spending a week with motivated and enthusiastic KDE hackers does wonders for my own motivation, so here we go:

In the last week I attended Akademy, the annual KDE community event - including the KDE developers community conference, an embedded development day and several days of BOF sessions. I was of course there with my Nepomuk hat on - in fact, with it pulled as far over my head as impossible, trying hard to hide the fact that given the choice I program in python not C++ and I use Gnome not KDE.

The event took place in Mechelen, Belgium - or actually in Sint-Katelijne-Waver, a 3-minute train-ride from Mechelen. The organization was excellent, Wifi never went down as far as I know (take that ESWC). The first two days were the developer conference, i.e. your standard fair of parallel tracks of talks. Interesting was Frank Karlitschek's initial keynote about the KDE websites (he runs kde-looks, kde-files, kde-apps, etc.), he pointed out that one of the main strengths of KDE is the community and we should bring this from the websites to the desktop. He imagined starting with things like showing KDE users in your neighbourhood in a Plasma-applet as a start and moving up to more collaborative features, like writing on the same document, etc. I was going to bring up Nepomuk an ideal for providing data-representation for such a venture, but someone else in the audience beat me to it - instead I quizzed Frank on the use of open standards for this later. He knew OpenSocial, but was not impressed, and had already made his own REST-based API, but confessed that he should look more on DataPortability for representing data (FOAF FOAF FOAF :)

On Sunday Laura did an excellent job with the Nepomuk presentation (she sat up all night to finish it :) and we had several interesting questions afterwards - which we discussed further in the BoF session on Wednesday. The issues popping up were, in order:

Indexing Performance (i.e. why does nepomuk take 100% of my cpu forcing me to turn it off?) when indexing lots of files, Redland is horribly slow, it is slightly better with Sesame.
Packaging - depending on Java to get Sesame is problematic - but (some guy?) said it should be possible to use Sesame with OpenJDK and he even tried it during the BoF session and said it worked fine. That leaves just to political problem of putting Java in the core of KDE.
Merging data - given a PIMO person with corresponding crawled/akonadi'ed address-book entry, facebook profile, twitter profile, etc. How can we combine the different parts of that person into one consistent view? In Java-Nepomuk this is the area of the LocalDataAlignment component -- where the mapping required is coded explicitly in Java. Solving this problem generally is very tricky -- but half-decent application specific things can be done with SPARQL construct queries.

The rest of the week include the free gifts of N810s to all Nepomuk developers (and me :) - thanks Nokia! - chatting more with Akonadi people about identity on the desktop vs. the web, a trip to Brussels, a boat-trip and a lots of Belgian beer :)

On the boat-trip I also learned that the kdebindings project not only has python, ruby, C#, etc. bindings for nepomuk and soprano, but also that it includes code to map soprano to ActiveRDF! Time permitting I will shortly try to mirror this with a rdflib Graph interface implementation on top of Soprano.

All in all this was an excellent event and I would not hesitate to pay my own way next year should my employer be unwilling! My photos are of course on flickr or Techbase for a general set of links.

Why've you drugged their onions!?

It's been a long time since an update here now, been busy bowling and drinking beer mostly. The bowling team is doing well, think we have a real shot at making it in the tournament this year. Got my favourite bowling ball from the bowling ball shining place yesterday, so now I'm ready to rumble.

Haven't had much time to play Starcraft lately though, and I'm afraid that mnem has been playing online an practicing.

At� logo.

Scripting for the Semantic Web Workshop!

Once again we organise a scripting workshop at ESWC this summer. The CFP is making rounds on mailinglists as we speak.

Have a look at the Scripting workshop page and submit a paper before the 7th of March! As usual there will also be a scripting challenge - details coming.

If you need more motivation, look here :)