Hi, I am Martin Ueding, a physicist (Dr., M.Sc.), machine learning researcher and software developer.

Although I am German, most of the content on this website is in English as both science and programming is communicated mostly in English. Lately I have written a lot of traffic policy and cycling, which is in German.

Since 2011, I studied Physics at Bonn university. I have finished my Bachelor degree in 2014 and my Master thesis in 2017. My dissertation was finished in 2020. See the studies section for the study related material.

At the age of 13 I started programming with C. Then I looked into HTML and CSS, started to use PHP and then MySQL. Looking for something to write software with a nice user interface with, I came to Java. Then I looked into more languages like Bash, Python, JavaScript, GNU Octave, VimScript, Fish. From then on, I tried to do most things in either Python 3 or C++11, so that I only have two languages, which I know well. For my work I now use R and also picked up the Wolfram Language, personally I looked into Haskell. See my portfolio.

My most popular project are the thinkpad-scripts which I wrote to get all the screen and digitizer features working effortlessly on my ThinkPad. It is a collection of Python modules that take care of docking and screen rotation.

For several years now, I have been almost paperless. The main challenges are papers I get from other people and hand written notes. The former can be faced with a scanner, the latter was more interesting. I own a Wacom Tablet since long before I started to become paperless, but I never had a good software for note taking. Since I did not find one at first, I wrote jscribbe. After I was almost done with that, I discovered Xournal which I now use most of the time.

You can also find me on other platforms:

Bluetooth Incompatibility

I have a hate-love relationship with Bluetooth. I would like to like it, but it always turns out to be frustrating. The idea of having a short-range wireless standard which allows coupling devices to each other is great. And on humble days I find it amazing that it works to the extent that it does.

Bluetooth has long been what USB is becoming, namely an opaque mess of incompatible devices where a layperson cannot determine whether they will be compatible beforehand. The box will only say “Bluetooth”, perhaps something like “Bluetooth 4.2”, but what does this really mean?

My latest frustrating example is with my bluetooth keyboard and my TV. My TV has already successfully paired with my headphones, and my phone can pair with the headphones and the keyboard. But the TV cannot pair with the keyboard. In order to see whether they had a theoretical chance to work with each other, I looked up the Bluetooth versions:

Device Model Bluetooth
Headphones Sony WH1000-XM3 4.2
Laptop Lenovo ThinkPad X220 3.0
Keyboard Logitech K380 3.0
Phone Xiaomi Mi A1 4.2, A2DP, LE
Tablet Samsung Google Nexus 10 3.0, A2DP
Tower PC Mpow Bluetooth 5.0
TV Samsung GU43TU8079 4.2

From this table I see that the TV and the phone have the same bluetooth version, so why does the keyboard work with the smartphone but doesn't work with TV?

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Fragmentation of Stack Exchange

For years I am a user of Stack Overflow and network of sites called Stack Exchange. My network profile has a long list of accounts that I have within the network. The sheer amount of sites became really annoying for me years ago, and today's experience was the straw that broke the camel's back.

As I finished the post about Bluetooth incompatibility, I thought about asking online and postedn on Super User. I chose the Stack Exchange network as I have a question and want an answer. And Super User seemed like the best fit for consumer hardware. My question was closed because it was not within the defined scope. Although Super User is about computer hardware and software, it is not about electronic devices, even if they interface with the computer. I have asked the moderator who closed the question which site would be a better fit for this, and got “no idea” as an answer. Great!

Fortunately somebody has asked on the meta discussion page for Super User where one can ask questions which don't fit on Super User. The top answer is really funny to read while writing this blog post. My question might fit into the “Phones and Tablets” category there, but the device is neither an Android, iOS or Windows based system. So all the specialized sites are off, and there is no Tizen specific site. For electronics equipment one could go to the “Electrical Engineering” site, just not if it is a consumer device. For video games and consoles there is an additional site, but this doesn't fit either.

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Height Adjustable Monitors

Decades ago I used to sit like a turtle when using my computer. The monitor used to be very low on the desk, and my back and neck would adjust for that. Over the years I acquired a much better posture, and I eventually bought monitors with adjustable stands. They sound amazing, and I cannot take any monitor without one serious anymore.

There is a catch, though: Their maximum height is severely limted. The Dell P2314H that I have offers only a limited range of adjustment. Neither the manufacturer nor various online resellers state the exact range. At the highest position, the center of the VESA mount is only 33 cm above the desk. As I usually work with command line windows and enter stuff at the bottom of the screen, I like to have the screen center slightly below eye level. Most ergonomics guides recommend having the top of the screen at eye level.

So I started to put books under it. And it really gave it this college student look.

Eventually I looked into monitor arms and saw premium ones for like 250 EUR. I just didn't want to spend more on the arms than the monitor itself, so I passed. Last year I looked into arms again and found some more affordable models and setteled for a dual arm model for 60 EUR. On the product page it said 40 cm which sounded good at first.

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Secure Portals instead of Secure E-Mail

E-mail itself is a completely insecure message service. Mails are routed through all participating servers on the world, everyone can send them. And whatever washes up in your inbox could come from anyone. It is not that bad any more, the connection from sender to sender's provider and recipient and recipient's provider is usually transport layer encrypted. The connection between the providers is becoming encrypted as well, but there is no guarantee. Essentially the providers can still read the messages, which is unacceptable for confidential messages.

In order to mitigate this problem and introduce some end-to-end encryption, e-mail protocol extensions like S/MIME and PGP have been invented. Both basically work with key pairs that everyone has to have and some vetting mechanism. In the S/MIME world the key pairs are called certificates and the vetting is done via central authorities (just like with HTTPS-certificates in the browser). PGP uses a “web of trust”, where people have to sign each other's keys to provide trust via trusted parties.

The user experience of both has been catastrophically bad. Some e-mail clients supported S/MIME, I believe that Outlook and Thunderbird did and do so. Obtaining certificates was a big hurdle. When I went to school, I didn't afford to buy one, and none of my peers did either. It was just something which was useless to have unless everyone else also has one. Instead I tried PGP in the form of GPG, but except from select other nerd friends, nobody cared for it. A plugin was needed in Thunderbird, and often enough it did not work. Keys had to be revoked, people encrypted with the wrong key (often their own), and so on. In theory, both are completely secure end-to-end solutions. In practice their are useless as people don't have certificates.

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Vertical and Horizonal Market Segmentation with Movies

Around the 2005, there wasn't really an online streaming market. Movies and series would be distributed via movie theaters, DVD or TV networks. Usually cable networks had stuff earlier. But for movies one would always have to wait until it was done in theaters in the USA. Then it should be shown in theaters in Germany and eventually it would be sold on DVD. And even later it would be aired on TV. With series it was usually that a whole season was shown on cable TV in the USA, and once that was done it would be started in Germany. I remember that when CSI NY season 2 was finished in German TV, I was really stoked for season 3. But they started airing season 1 again as the third season was not done in the USA yet.

So basically one had a market segmentation like this, where there are various horizontal layers and the segmentation is done vertically:

The studios would produce stuff, there was a bunch of licensing stuff in between and eventually one could just see the stuff on German TV. One could watch everything with the same TV, just had to wait rather long.

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Bonn tut etwas gegen Falschparken: Legalisieren

Als ich noch in Endenich gewohnt habe, bin ich dort immer wieder zu Fuß einkaufen oder spazieren gegangen. Dabei kam ich dann an diversen Stellen vorbei, an denen Autofahrer den Gehweg als Parkplatz genutzt haben. Mir geht es ziemlich auf den Geist an solchen Stellen entweder hintereinander oder auf der Fahrbahn gehen zu müssen. Insbesondere mit einer Einkaufstüte nervt es. Davon abgesehen ist Gehwegparken verboten, weil es illegal ist. Je nach Tagesstimmung mache ich ein Foto und schicke das über Weg-Li an die Stadt Bonn.

Bei der Verwaltung hat man wohl die Häufung der Anzeigen um meinen Wohnort festgestellt und sich überlegt, dass man doch endlich mal gegen das Falschparken etwas machen müsste. Und anstelle das Ordnungsamt regelmäßig dort kontrollieren zu schicken, hat man das Falschparken ganz kreativ abgestellt: Man hat es legalisiert und das Zeichen 315 aufgestellt. Im Kollegienweg sieht vorher (links) und nachher (rechts) dann so aus:

Man bemerkt solche Änderungen ja nicht direkt bewusst, aber irgendwie kam es mir merkwürdig vor. Ich zweifelte schon an meinen Anzeigen, hatte ich die ganze Zeit das Zeichen dort übersehen? Aber der Vergleich mit alten Fotos zeigte den Vorgang deutlich.

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Bundesbetonhovenstadt Bonn

In Beuel-Mitte an der Rheinlust gibt es jetzt eine neue Anzeigetafel, anscheinend für ein Parkleit- und Verkehrsinformationssystem. Also etwas, das nur Autofahrer brauchen. Und wo wurde diese Tafel aufgestellt? Natürlich nicht auf der Fahrbahn, sondern daneben. Das ist ja okay, man ist es nicht anders gewohnt.

An dieser Stelle stört mich aber besonders, wo genau es aufgestellt worden ist. Man hat dort links einen Radweg (für beide Seiten) und rechts einen Gehweg. Diese sind durch diese taktilen Platten voneinander getrennt. Der Radweg ist für den Begegnungsverkehr schon zu eng. Der Gegenverkehr fährt meist sehr weit zur Fahrbahn, das Lenkerende ragt dann über die Pflastersteine. Vor dem nächsten Mast für die Oberleitung muss man dann wieder ausweichen. Und der neue Mast wurde ganz nah am Radweg plaziert.

Ich verstehe wirklich nicht, warum. Zur Fahrbahn ist noch genug Platz, dass selbst große Außenspiegel nicht abgefahren werden können. Es wurde links vom Mast viel toter Raum geschaffen.

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Publication of the PhD Thesis

I've defended my PhD thesis on 2020-11-26. After that I needed to publish my thesis in order to receive my PhD diploma. This is more complicated than it sounds.

Decades ago, when one did not have servers with PDF files, one had to publish the thesis with a lot of hard copies. And this unfortunately is still the default mode at the University of Bonn. So there are a bunch of hoops that one has to take in order to have the thesis published.

I took a couple days before I started this process. On 2020-12-01 I sent the PDF file via e-mail to the university library. They have a special address where I should sent it to. As the PDF file was so large, I have just uploaded it to my website and gave them the link.

In parallel I needed to register my thesis on some other platform of the library. There they did not accept the PDF, just the meta data. And the form had a “Submit” and a “Reset” button there. I mean, how many times does one actually want to reset a form? I thought that this “Reset” button died out decades ago. After registering my thesis there, I had to download a receipt, sign it and send it via e-mail to the university library.

On the website of the library they told me that I needed to make sure that my advisor is okay with me publish my thesis electronically. They did not mention any particular form. So I just asked my advisor and it was okay.

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Fahrräder sind breiter als Autos

Ich habe eine steile These: Fahrräder sind breiter als Autos. Zumindest im Mischverkehr.

Laut § 32 StVZO dürfen Personenkraftwagen maximal 250 cm breit sein [bussgeldkatalog.net]. Ein für Bonn realisitisches Beispiel ist ein aktueller Audi A6 mit 211 cm Breite mit Rückspiegeln [angurten.de]. Ein Fahrradlenker ist eher so 75 cm breit, das ist erstmal deutlich schmaler. Selbst mit den Ellenbogen dazugerechnet kommt man gerade mal auf 100 cm Breite.

Interessant wird es dann aber bei den ganzen zusätzlichen Abständen, die man beim einhalten muss. Als Radfahrer muss nach rechts 100 cm zu parkenden Autos einhalten, nach links müssen die Autofahrer 150 cm beim Überholen einhalten. Und schon haben wir eine dynamische Gesamtbreite von 350 cm.

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Geier im Internet

Ich bin immer wieder mal auf Jodel unterwegs. Das ist eine App, bei der jeder irgendwelche Text- oder Fotobeiträge posten kann. Angezeigt bekommen diese dann Nutzer in der geografischen Nähe. Das führt dazu, dass man Beiträge aus der Nähe bekommen kann, ohne dass man nach bestimmten Personen suchen muss. Zusätzlich ist das ganze anonym, man hat also kein Nutzerprofil, Follower, Abos oder irgendwas. Man ist in jedem Beitrag komplett neu und wird einfach nur nach Antwort-Reihenfolge durchnummeriert.

Leute stellen dort Fragen (»Hat der Bäcker am Hauptbahnhof wieder auf?«), machen Lokalanzeigen (»Hat jemand einen Toaster abzugeben«) oder laden zu spontanen Dingen ein (»Bin auf der Hofgartenwiese, will jemand Frisbee spielen?«). Es gibt auch einen Raum eher peinliche Fragen zu stellen.

Allerdings lädt die Anonymität auch dazu ein, die dunkelsten Seite zum Vorschein zu bringen. Da es keine Profile gibt, kann man einem Beitrag nicht direkt ansehen, ob er von einer Frau oder einem Mann verfasst worden ist. Manchmal wird es aus dem Inhalt klar, manchmal kann man es vermuten, manchmal ist es ganz offen. Und sobald nur annähernd vermutet werden kann, der Beitrag könnte von einer Frau verfasst werden, beginnen die Geier zu kreisen. So nennt man auf Jodel die Männer, die nur darauf warten, mit der vermuteten Frau in Kontakt treten zu können.

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