Fourth #Recsys Stammtisch Berlin

2012-10-23 22:38
This evening the 4th #recsys Stammtisch (German for "a meetup involving beer") was kindly organised by Alan Said, Zeno Gantner and Till Plumbaum. The event was hosted by Aklamio with beers and drinks provided by Plista. They had three talks:

  • @AlanSaid gave an overview of the topics covered in this year's RecSys conference in Dublin. Instead of going into too much technical detail the presentation gave a whirl-wind tour of the topics that are currently under discussion, the competitions to participate in and links to people relevant to the topic to follow up with. He put his slides online already.
  • As second speaker the meetup had @zenogantner give a tour to his MyMedialight recommender system library. Though written in c# there is no need for a deep c# knowledge to use the system - it comes with useful command line tools out of the box, supports all common algorithms and evaluation setups. One of the few talks where life demos actually worked.
  • The third talk - one of the rare "slide-free" presentations - covered Plista and it's relation to recommender systems. After going into some more detail on where they came from (from a big over-arching solution down to the narrow, sharp focus of doing ad recommendations), where they want to go (back to an over-arching solution to be offered as a service with the goal of bringing interaction data of many services together in one hosted system). Most interesting news to me: They are working on an open source web-service layer for Apache Mahout that seems to be already in production. Definitely something to watch.

Overall a good crowd of over 20 people from various startups, universities and larger companies in Berlin joined the meetup. There were even some people travelling there from Magdeburg. Pretty good to know that there are so many people knowledgeable in the general area of recommender systems in and close to Berlin - and good to see some of those I knew already before the meetup again. Looking forward to the next event - any volunteers for organising one?

Teddy in Meißen

2012-10-23 20:19
Taken earlier this year in Meißen the picture shows a detail of the beautiful cathedral:

Teddy after a busy day:

Note to self: Basic R operations

2012-10-18 22:55
After searching for that all too often and for too long (in particular the "add a column as index" bit):

  • To read a file: d
  • Useful for getting an overview of the data:summary(d); head(d); tail(d)
  • For sorting some data frame: s
  • For adding a column to a data frame: s$idx
  • For plotting a column: ggplot(s, aes(idx, engagement)) + geom_point() +scale_x_log10()

Note to self - link to 3D maps

2012-09-24 08:39
After searching for the link the third time today - just in case I happen to be again looking for Nokia's 3d maps: is the non-plugin link that works in Firefox.

Some thoughts on a conf taxonomy

2012-09-16 12:53
One common way for open source developers to meet face-to-face is to attend conferences relevant to their subject of interest. A common way to have one near you if there ain't none yet is to go and organise one yourself. The most obvious stuff to resolve for that task:

  • Most likely there will be some financial transactions involved - sponsors wanting to support you, attendees paying for their tickets, you paying for the venue and for food.
  • Someone will have to choose which speakers to invite.
  • How to scale if there are more speakers and attendees than you can reasonably welcome yourself.

So far I've come across a multitude of ways to deal with these two issues alone. Some encountered at events with >200 attendees are listed below. Feel free to add your context.

Name Content selection For profit Tickets Food Scaling model
FOSDEM/ Brussels open CfP, decision by organisers Nope - it's hosted by a university, organised by a couple of students and an incredible multitude of volunteers. Access is completely free though attendees are being asked to support the conference with a donation. Food is on sale through the organisers In addition to two main tracks there's a multitude of independently but affiliated and co-located so-called dev rooms that are completely community organised e.g. for Debian, Java, Embedded, KDE and others
Froscon open CfP, decision by organisers Nope - again hosted by a university, organised by a couple of students and volunteers Tickets are cheap - in the 5 Euro range Food is on-sale at the event. There are workshops and related events that are community organised. Those are starting to get more visible in the main program as well.
Linux Tage Chemnitz open CfP, decision by organisers + committee. Nope - hosted by TU Chemnitz with huge local support. Cheap - in the 5 Euro range. On sale at the event (soup and related stuff). Stable number of attendees so far.
Chaos Communication Congress open CfP, decision by organisers + committee yes for four days slightly less than 100,- Euro on sale in the venue as well as around move to different location
Chaos Camp open CfP, decision by organisers + committee yes 100 < prize < 500,- range for whole week including camping ground on sale at the location not needed so far
Berlin Buzzwords open CfP, decision by volunteers yes more than 300,- Euros in early bird included in the price affiliated workshops
ApacheCon open CfP, decision by volunteers yes in EU >200,-, in US usually >1k$ included in price affiliated meetups
Lucene Revolution open CfP, decision by organisers more or less, mainly PR for organiser >500,- included in price not needed so far
GoTo Con invitation only yes >500,- range included in price turn the "one location" only conference into a series that moves across Europe with the help of some locals that are interested in having the event
Strata open CfP, decision made by committee - final decision by organisers yes in the >500 Euro range included in price split in different locations, organisers remain the same still

From the above table to me it seems that most conferences differ in whether they are fully non profit solely for the sake of education. In contrast to that there are events that are for profit (as in support the organisers financially), or some kind of self-marketing where profit is indirect in terms of more contracts signed. They also differ in whether submissions are open or invited talks only. In addition there are those that have paid talks (usually clearly marked as such) or accept talks through the submission form only. In terms of cost one model is to go extremely low-cost with no money paid for venue or food vs. those that include catering in the ticket price.

Me personally I have a strong preference to events that feature an open CfP - mainly because talks tend to be more diverse and - given a strong program committee - also of decent quality as only the best make it through. In addition the events tend to be less formal when fully community organised - over time regulars among speakers, attendees and exhibition participants tend to know each other generating a rather friendly athmosphere.

Speaking at ApacheCon EU 2012

2012-09-15 12:47
I'll be at ApacheCon EU in November. Looking forward to an interesting conference on all things Apache that is finally returning back to Europe. Go there if you want to learn more on Tomcat, Hadoop, httpd, HBase, Camel, Open Office, Mahout, Lucene and more.

Now on to prepare the two talks I submitted:

  • "Choosing the right tool for your data analysis task - Apache Mahout in context"
  • "I was voted to be committer. Now what?"

Looking forward to see you there.

Learning German

2012-09-14 08:07
For some reason I got that question multiple times now from people that moved to Germany but work in companies where English is the language to use for communication - how to best learn German (in addition finding people to talk to).

When thinking about how I got started with English there were a few things that helped: As a child I got some "made for learning English" crime stories to read. In 11th/12th grade we got a Newsweek subscription. When at university I quickly learnt that translations of any man pages or help files to German were not really helpful so I switched my Locale to English. In addition the dubbed versions of Futurama were no good - same for most movies you get to see in cinema. Finally getting into open source meant that there was no other way for communication.

So what sites are there that provide value to the average geek but are available only in German?

Blogs and online resources

Newspapers etc.


Some music and movies:

If you happen to live in Berlin - also take a look at local magazines pointing out current events and special exhibitions. There's also quite a few books in and about Berlin. Make sure to safe some time to vist the Bundestag and book one of their lectures.


One hint from Thomas Koch: Die Deutsche Welle hat unglaublich viel Material, auch einen
kompletten mehrsemestrigen Deutschkurs als Podcast + begleitende PDFs.

Thomas, thanks! On a similar note - the archive of DRadio is also well worth a look.

Moving to a new domain

2012-09-12 12:30
Executive summary: This is to warn those of you who are subscribed to this blog - the domain to reach this blog w/o redirects will soon change to by - you might want to adjust your rss subscription accordingly.

Longer version: This blog post is scheduled to go live some time after lunch-time on September 12th 2012. You might have heart rumors before - that date Ms. Isabel Drost and Mr. Thilo Fromm are supposed to get married.

There were times when war and conflicts between kingdoms were settled by having children of the reigns get married. Today this old tradition is being continued on a much smaller scale by having a couple get married that is comprised of one half being passionate about Linux Kernel hacking and a strong proponent of GPL/LGPL open source licensing and the other half coming from the Java world, mainly contributing to ASL projects.

As a bit of "showing of good will" both agreed to the proposal of Matthias Kirschner: Girls that are FSFE fellows really should only marry other FSFE fellows. So we got Thilo a fellowship membership setup very quickly.

PS: Now looking forward to dancing into a new part of life this evening ;)

Pps: Thanks to photomic for the DLSR fotos, and to masq for taking the above picture and mailing it to my server. Having a secure shell on your mobile phone rocks!

Video up: Dragan Milosevic on "Robust Communication Mechanisms"

2012-09-11 08:06

FrOSCon - on teaching

2012-09-09 08:17
The last talk I went to during FrOSCon was Selena's keynote on "Mistakes were made". She started by explaining how she taught computer science (or even just computer-) concepts to teachers herself - emphasizing how exhausting teaching can be, how many even trivial concepts were unknown to her students. After that Selena briefly sketched how she herself came to IT - emphasizing how providing mostly the information she needed to accomplish the current task at hand and telling how to get more information helped her make her first steps a great deal.

The main point of her talk however was to highlight some of the underlying causes for the lack of talented cs students. Some background literature is online at her piratepad on the subject.

The discussion that followed the keynote (and included contributions from two very interested, refreshingly dedicated teachers) was quite lively: People generally agreed that computer science/ computing or even just logical and statistical thinking plays a sadly minor role in current education. Students are mainly forced to memorize large amounts of facts by heart but are not taught to question their environment, discover relations or rate sources of information. The obvious question that seemed to follows was that on what to remove from the curriculum when introducing computing as a subject. My personal take on that is that maybe there is no need for removing anything - instead changing the way concepts are taught might already go a long way: Put arts, maths, natural sciences and music into context, have kids evaluate statistics and rate them not only in maths but also in e.g. biology by letting them examine some common statistical fallacies in the subject area.

Another problem stated was the common lack of technical understanding, the common lack of time for preparation and the common lack of understanding for the concept of open source or creative commons content. Taken together this makes sharing teaching material and improving it together with others incredibly hard.

Selena's call to action was for geeks to get involved and educate the people near and dear to them instead of giving up. On thing to add to that: Most German universities have some sort of visitors' days to prospective students - some even have collaborations with schools to do projects together with younger ones - make sure to check out your own university - you might well find out that teaching is not only exhausting but also particularly rewarding especially when teaching students that really want to know and participate in your project just because they want to.

If you know any teachers who are open to the idea of having externals take over some their lessons or at least provide input get them connected with your peers that are interested in educating others. Also keep in mind that most open source projects, hacker spaces and related organisations in Germany are so-called "gemeinnütziger e.V." - a status that in many cases was achieved by declaring the advancement of education as at least one of their goals.