So, after signing up for the service back in Portugal it was time to install the antenna so we could watch portuguese TV here in Darmstadt. I haven’t stuck the thing into the wall yet but I wanted to test it before the weekend so after a lot of pointing at the air (I didn’t use a compass) I got it to work. The thing you see serving as a support is a rotative chair without it’s top part 
Professor Randy Pausch passed away this morning.
If you have not seen his video, “Really Achieving Your Childhood Dreams”, please do so.
http://youtube.com/watch?v=ji5_MqicxSo
Thank you for the inspiration.
I’ve just been “exposed” to this software requirement:
“No memory leaks shall exist. ”
I’m glad someone thought of this one!
Today we cycled to the Frankfurt Main airport, the second biggest airport in Europe. It took us quite a while to get there (~1h30) at a medium pace I would say. After watching a few landings and some takeoffs we went for food at a nearby biergarden and begun cycling back to Darmstadt (Griesheim). The map says it was 40 km but think it was more!
Seems one of the developers that was working on one of the modules asked what icons should be shipped with the software and the client said it wasn’t important so he ended up choosing some icons according to his own taste.. which is kinda cool because now I’m working on the software and have these funny icons on the desktop:
The guy didn’t use the default gray icon, he wanted something better and funny and not the minimum that can be gotten away with. By the way, the icon on the right is Frank Zappa.
We cycled to Ludwigshöhe Tower and then to Roßdorf via Ober-Ramstadt.
We cycled through Griesheim, Wolfskehlen, and Leeheim, which is basically where the road goes. From Leeheim, we carried on straight to the Rhine through Sonnenhof and on to Kornsand, whereas the road goes north a bit through Geinsheim. It took about an hour to get there.
This map shows it quite well… click here.
There is this thing called “Time Correlation” and questions about it pop up in work every now and then. I’m just now beginning to scratch the surface of what this thing is and thought that writing something down here and explaining it might help organize my thoughts and give a small glimpse of what this is.
Timestamping the things that happen on the spacecraft (e.g. execution of commands, transmission of data, instrument measurements, etc) is very important as one can imagine. It is not so simple as putting a normal (or even a very good quality) clock on-board because it is known that clocks drift from actual time every once in a while. This led someone to come up with a very simple scheme to determine more accurately the time on-board.
This scheme begins by having a simple counter on-board. We can think of this counter as a simple integer sequential counter that counts 1,2,3,4, etc. incrementally. This counter is sampled every N frames (think sequence of bytes if nothing else) that are sent by the spacecraft and a packet is created with the counter value.
At the ground, the reception time of the frame is recorded and associated with the counter value in a pair. By looking at several of these pairs and performing a correlation it becomes possible to convert the integers into actual UTC time.
Here’s the funny thing, the counter value is sampled at the exact moment one of this frames begins being transmitted. It is not possible to sample the counter and transmit at the same time (maybe because of the backlog queue of frames?). This means the sample value will be delivered later on a separated packet, one that is not included in the frame just transmitted. So what do we do? Since the counter is sampled every N frames we look into the previous Nth frame and its reception time on earth * and save it until we get the next sample value. Once we do, we are sure that, if we subtract the transmission time from the value we had saved, we will get the time of last sample of the counter value
This is a bit tricky at first but extremely easy once you get it. I’m happy to try to answer some questions on it if anyone’s interested.
And this was the whiteboard after some drawings on time correlation..
* Since the orbit of the spacecraft is modeled on earth we know at each point how long it will take for such a transmission to get to earth. This can go from seconds to hours as you can imagine (depending on the distance, etc). This transmission time is called One-Way-Light-Time (OWLT).
Most people work in their home country and go on holidays abroad. This year we decided to do it the other way around, to work abroad and go on holidays to Portugal. Well, actually its more complicated than that but what matters is that we now have bought our tickets to Portugal for our vacations. We’re going on the 25th of July and returning on the 10th of August. After all, Portugal is one the best holiday locations I know of (if not the best 
attention I’m biased). I hope to get together with my friends, catch some sun and bath on the ocean again.
A couple of weekends ago I went to Oppenheim I found this formula in several doors around the village. I was so intrigued I had to ask what it was all about. It seems it’s a catholic custom. The “Sternsinger” (star singers) are kids dressed up as the kings from the east (http://en.wikipedia.org/wiki
When those kids visit a house they leave that strange formula written on it. Thanks to Joerg for the explanation
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