Je suis revenu sur mon expérience avec mon livre de thermodynamique dans un article publié aujourd’hui sur le Framablog : Mais où sont les livres universitaires open-source ?
Cette année, le projet Wikimedia Commons, la base de donnée multimédia qui se cache derrière les projets Wikipédia, fêtera son dix-huitième anniversaire. Je connais bien cette communauté puisque je m’y promène presque tous les jours, pour le travail et mon loisir, depuis dix ans. Wikimedia Commons est une caverne d’Ali Baba, incontournable pour l’édition d’un de documents éducatifs libres. C’est là que vous allez pouvoir trouver, déposer, améliorer les photos, schémas, diagrammes dont vous avez besoin : par exemple, le circuit d’eau d’une centrale thermique, une image de 400 megapixels de la baie de San Francisco, une illustration sortie d’une publication de recherche publiée en 1820 ou un schéma vectoriel illustrant la notion mathématique de dérivée en espagnol. Malheureusement, on dirait que quelque chose s’est coincé et que le projet est resté figé en l’an 2000. Me croirez-vous si je vous dis que l’entièreté du projet — son système de mesure de qualité, d’organisation interne, et surtout, toute sa base de données — est basée sur du wikitexte ? Wikimedia Commons est un projet unilingue, qui souffre d’un manque catastrophique de diversité. Il est fait surtout d’éditeurs amateurs (j’en fais partie) qui aiment bien prendre des photos de trucs dans des musées et qui passent leur temps à trier les photos une à une à la main parmi les sous-catégories de « Catégorie regroupant les Airbus A320 de la British Airways triés par aéroport » et « Catégorie regroupant les couchers de soleil photographiés depuis les plages de la région de Kerala ». Le projet a raté le cap de la vidéo, celui de l’internationalisation, celui de la transition vers les appareils mobiles, et je ne parle même pas des médias interactifs ou en trois dimensions, qui y sont complètement inconnus. Il se montre incapable d’accueillir convenablement les contributions de professionnels et d’entreprises, ce qui représente une perte énorme. En bref, ce projet a besoin d’une reprise en main et d’une feuille de route ; il faut qu’il consentisse des efforts pour diversifier sa communauté, pour s’organiser en suivant les recommandations de professionnels, pour se doter d’outils contemporains facilitant la découverte, l’utilisation et le remixage des œuvres hébergées. Sans cela, il restera simplement une « galerie d’images pour Wikipédia », passant à côté du rôle formidable qu’il pourrait jouer en devenant la banque multimédia universelle du monde de l’éducation. Je lui souhaite de réaliser tout cela cette année !
It’s hard to describe to other people what it feels for me to listen to Keith Jarrett’s music, because it sounds so mystical. It’s sorcery. When it finally works and the fire has been lit up, it is an opening of oneself, an immense liberation. I am possessed by the music and possessing it at the same time. It’s a connection to something greater that has been there all along, and the sudden certainty that everything so far that has led to this moment has been worth it. It’s a feeling a little like “telling the truth”. Whatever.
A thoughtful member wrote on the Keith Jarrett discussion group that all it takes is attentive listening to be taken to a different place. To me, this is true only some of the time. I feel inescapably bound to making the music appear, some days I can effortlessly feed my mind many hours of it and sometimes it takes months before I can again listen to Jarrett improvising. It’s a struggle, what is recorded in the audio file seems to be more like the key to something within me for which I can’t always find the lock. After twenty years of listening I am still confronted to this every time. If I am at the same time playing the piano in 1973 and being the entire audience there and listening in my bedroom today, then why do I have so little command over experiencing this elevation?
Certainly Jarrett must have his own set of confrontations and conflicts too. He is the ultimate link between all of us and something beyond, and at the origin of all those ephemeral “manifestations”, for lack of a better word. But at the same time he is a professional performer, expected by everyone to produce those on order in two-set events that are booked in advance. Later, at commercially sensible intervals, the magic is pressed into shitty little rectangular plastic boxes wrapped in cardboard stamped with a brand of the largest and meanest music corporations of the planet.
I think Jarrett’s troubled relationship with his audiences is sincere. I don’t believe he is arrogant. I think the audience and the improvisation are parts of what makes it all work; that he is torn between wanting to soar with all of us and being, time and time again, disappointed when he finds that two thousand humans are just as messy as everyone else could have predicted. I saw him reject audiences in ways meant to hurt, and I pity him — if only he had Chick Corea’s or Hiromi Uehrara’s good spirits! To make things worse, his relationship to technology is superstitious, and I find, ill-reflected. But he is walking on the crest of mountains, telling us of the other side, and I readily believe the crest is really sharp and treacherous.
I think of him with kindness. Jarrett recently suffered a stroke that left him unable to play. We, and especially him, are orphans now. I wish him well.
If you are paying revenue tax in Germany, the German federal government can support you financially with your donations, in the form of reductions in your revenue tax. The process is not particularly complicated, but not well documented in English on the Internet. Here is how it works, based on my readings online, my understanding, and my own experience.
(I am not a lawyer. I share this information in good faith. It may not be accurate.)
Which donations are eligible?
Donations to non-profit organizations working for the public good in the European Union are eligible for tax deductions in Germany. Either the organization is eligible, or it is not; there is no grid or graduation. The government must consider every donation you declare for eligibility; it may then accept or refuse them.
Membership fees to non-profit organizations working for the public good are considered as a donation. In general, if you receive a donation receipt from the receiving organization, it is safe to assume the donation is eligible. If in doubt, contact the receiving organization to check their eligibility status with them.
How much help will you get?
The sum of your donations is subtracted from your yearly taxable income. The donations will therefore result in a decrease in both your income tax (Lohnsteuer) and solidarity tax (Solidaritätszuschlag).
For relatively small donations (e.g. 100 euros), this means that the amount of help received from the Government corresponds to your marginal tax rate (the tax rate at which the last 100 euros were earned). As a researcher in a public university, my marginal tax rate reaches up to about 35% when working full-time. For my first donation of 200 euros, I get approximately 70 euros back as a tax deduction.
Determining your marginal tax rate (Grenzsteuersatz) is not particularly easy. The German marginal tax rate depends on the taxable income, an amount which is neither indicated in your pay slips, nor on your yearly tax bulletin (the Lohnsteuerbescheinigung). The taxable income (zu versteuerndes Einkommen) is your gross income minus a number of social contributions (retirement pensions, social security), minus a standard threshold sum. As a researcher in a public university, my taxable income is close to 80% of my gross income when working full-time.
The marginal tax rate varies continuously with the taxable income, which has two interesting consequences. First, the more you earn, and the larger the amount of support you receive from the government. If your income varies with time, then it is in your interest to make those donations on the years when you earn the most. Second, the more you donate, the smaller the amount of support you receive (successive donations are subtracted from slices of your income which are progressively less taxed, e.g. the first donated 5000 euros were taxed at 35%, the next 5000 euros at 32%, and so forth).
Ultimately, donations can only be deducted up to 20% of your taxable income for any one given year. Donations over that amount may be carried forward to the next years without any limit in time.
How is the deduction carried out in practice?
Wait until the fiscal year is over. During this time, your employer declares and pays your taxes for you, assuming no donations took place.
Once the year is over, connect to Elster, the German federal tax website. Note that your “Steuerliche Identifikationsnummer”, which is sufficient to login, is not your “Steuernummer”, which is not always given to you by the German administration. Carry out a modification to your tax declaration. Donations are entered in the rubrics “zur Förderung steuerbegünstigter Zwecke an Empfänger im Inland” and “zur Förderung steuerbegünstigter Zwecke an Empfänger im EU- / EWR-Ausland”.
For donations prior to 2017, once your declaration is complete, you must send the original donation receipts to your local tax office (if you only send copies, they will write back asking for the originals). For all donations over 200 euros, you must also sent a proof of payment (e.g. an excerpt from a bank statement). A short letter with your personal information and a sentence similar to “Anbei finden Sie die Belege, die zu meinen Steuererklärungen für 2015 und 2016 gehören” suffices. In the case of donations outside of Germany, I like to include a short, half-page description of the organization to which the donation was made, to help officials assess whether the organization qualifies for a tax reduction.
For donations made after January 1st, 2017, you must be ready to send donation receipts and proofs of payment in case the tax office requests them. There is no obligation to send those documents spontaneously.
The Government is prompt to act and will issue a refund, together with a complete tax bill sent by paper mail, within a few weeks following your declaration. You can work on tax declarations for the past five years, declaring any donations for which you have kept receipts. The German government will treat them equally quickly, and even provide interest on the refunds from former years.
The support provided by German government when you make charitable donations is really substantial. It is in practice hard to predict exactly the amount of support you will receive. Nevertheless, the amount of required paperwork is small. I hope this can encourage you to increase donations correspondingly!
In the summer of 2020, I rented a drone and took photos and videos of Magdeburg, Germany. The photos are now all published on Wikimedia Commons and some serve to illustrate Wikipedia articles. I intend to use the videos as decorative features in the videos of course in engineering fluid dynamics. In the meantime, I publish them here, under a CC-by license: this means you are free to use them for all purposes, including commercial purposes, as long as you credit me (Olivier Cleynen).
It was a lot of fun playing with the drone, and capture shots of my beloved city. The files linked here are 2160p H264 videos embedded in Matroska containers, usually less than a minute long.
The semester began right as Germany shut down due to the pandemic crisis. The course, with 153 students, took place entirely online. I spent nearly half of the semester working from abroad, attending to a close relative. I was never able to meet any student physically.
The course progressed on a weekly basis. I released one chapter every week, a single PDF document containing lecture notes and problems. In the document, I linked to YouTube videos (on average, five per chapter) where I covered important elements of the theory, and solved problems step-by-step. I also linked to interesting illustrative videos. In weekly, two-hour Zoom sessions, I answered any and all questions that were thrown my way.
In addition, every student received individualized homework as part of the peer-graded homework program I developed with my colleagues Mathias Magdowski, Germán Santa-Maria and Jochen König. This year, participation in the homework was mandatory and counted 40% towards the final course grade. I hoped to run four instances of the homework, but in the end, because of personal matters, only three pieces of homework were handed out.
A series of weekly four-question quizzes, run through the University’s Moodle instance, added up to 10% of the final grade. The remaining 50% of the final grade consisted of the final two-hour invigilated examination, with the same structure (choose three problems among five) as in former years.
A lot has happened through the semester, and I have many mixed feelings about this edition.
First, I am glad I learned to record videos, and I think I got it right. A good-quality, subtitled recording of a problem being solved by hand (I used a Wacom tablet, an external microphone and an external webcam plugged into a laptop) is a much better tool to learn with than a live session in a classroom with a chalkboard. I chose YouTube as a compromise, because it suits students well, but will try to migrate to a PeerTube instance in the future.
Administrative management was a nightmare and cost me hours of work weekly throughout the semester. My university does not communicate well with either teachers or students —the local TV station knew of the revised semester dates before I did— and predictably the communication between teachers and students is chaotic. Additionally, my university has no effective control over the course registration process: for example, just getting an up-to-date list of student emails is a challenge. I hope better management will alleviate me of that load in the future.
Communication channels between students remained out of my reach for the complete semester. I heard WhatsApp groups are the thing; in any case the Moodle discussion boards of my course failed to reach critical mass. Too many students address me directly. I tried to redirect requests to the interactive Zoom sessions and Moodle forums, but in the end I count only 174 Moodle posts, and 860 emails sent and received over the semester (I do not count the 1800 mails processed automatically as part of the peer-graded homework program). An average of 4.5 mails received, 4.5 sent every day is just too much for one class. A few students are disrespectful (although always reverent), and many have completely unrealistic expectations, not having truly realized what it means to be a single instructor with 153 students on the side of research-related duties.
Zoom sessions went very well. The technical robustness of Zoom impressed me, especially in view of the low level of computer literacy and equipment of my students. Attendance (share of exam-goers present for 45 minutes or more) began at 65%, decreasing linearly with time down to 17% in the last session. I regret that so few students chose to turn on their camera, even though I respect their decision. As a teacher, I yearn for visual contact and body language during interactive sessions, but this semester, I ended up staring mostly at a wall of usernames.
One nice success was introducing illustrations of people in the lecture notes, to pass across important points in paragraphs titled “advice from an expert”. I had some illustrations made to order, and licensed others under a limited-use, commercial license, all following the advice of my colleague Dr. Kristin Hecht.
Those paragraphs had two purposes. First and foremost, I am tired of fluid mechanics being narrated mostly by old white men, and wanted to put different-looking people in charge of giving technical advice to students. I hope my students, almost none of whom look like me, can identify themselves with some of the persona displayed in the lecture notes now. Second, using this technique helped me with the tone of the lecture notes, which I had long found to be slightly boring and too serious. Now, I can keep the technical content short and precise, while indulging in a more relaxed tone on occasion, addressing the reader directly. For good measure, I also sprinkled links to a few of my favorite science webcomics (such as xkcd) across the chapters.
The largest pain point remains the grading. While the distribution of final grades remains largely the same as in the last five years, there is a large discrepancy between coursework and exam grades.
In the peer-graded homework program, there is evidence that a sizable share of students participated in bad faith, which resulted in low-quality grading of other students. This is an inherent weakness of the program: if too many students, even when handed a complete step-by-step worked-out guide, are unwilling or unable to identify the source of an error in the papers they grade, then they cannot be easily “sorted out” of the system, and global student motivation and learning will suffer.
There is also plenty of evidence that the system of weekly quizzes was abused. I had thought that because the stakes were low (quizzes amount to 10% of the final grade, so any one question weighs only 0,25%), there would be no incentive for gaming, and I was wrong.
Because of those issues, I went into the exam with the impression that coursework grades did not reflect the true level of learning of a significant number of students. The exam proved me right: with 55% of participants failing the exam proper, and 33% not even clearing a quarter of points, it was the worst student performance in record. This necessarily brings into question whether deploying coursework is actually worth the effort, since this year, it objectively correlates with lower learning.
There are many factors that come into play here, not all of which are under my control. First, this year the University lifted restrictions on the number of attempts allowed for each exam, and so some students may have been temped to have a “free try” (passed exams cannot be repeated however, which makes for weird dynamics). Second, grades secured with coursework reduce the pressure exerted on students during the exam. I have long understood that grades act as a metric for the student’s time budgeting, both within my course and in between different courses. This is completely natural, and I wouldn’t blame students for putting focus on other exams where the stakes were higher. (Proper quality measurement and management would substantiate those statements and help with strategizing, but unfortunately, my university is not there yet either.) And finally, the pandemic disproportionately affected students in my course, most of whom come from abroad. I can’t imagine what it means to work on an exam when you are barred from flying back home to take care of loved ones, or uncertain whether you can even keep studying through the coming semester.
Looking ahead, I need to make the grades better reflect the level of learning. Quizzes won’t be graded anymore, and I will likely make homework an optional, low-weight program again.
Ultimately, it is clear that there are students in my course who have not attended a single Zoom session during the semester. There are students who do not think it useful to invest 20 minutes watching the exam prep video I sent them before making an attempt. There are students who are not able to manipulate a simple equation that contains only symbols, and there are students who have no inhibition against writing uninterrupted nonsense for two hours on a paper. Surely, any of those last two issues preclude any success in an engineering fluid dynamics course. Before I make coursework a large part of the course again, I must be able to prevent those students from interfering with the success of others.
I cannot conclude this without mentioning the sheer joy that comes out of all this work. It is uplifting and humbling now to meet students on campus who took part in the course and express feedback. This coming year, with most of the course content now solidly covered with 15-minute videos, I will be in a much better position to follow the footsteps of my colleague Dr. Steffi Knorn and flip the course around. My vision is to be spending all of my class time helping students actually solve realistic problems in fluid dynamics, using modern tools and techniques. I look forward to 2021.
I own a city bicycle with a very nice 3‑speed Shimano Nexus 3 wheel hub. It is the SG-3C41 model, which has an integrated coaster “backpedal” brake. (The SG-3R40 and SG-3D55 models don’t have that.)
I really dislike coaster brakes, which throw me off balance when maneuvering at low speeds, make starting from a standing position difficult, and generally diminish my feeling of freedom of movement when riding.
Fortunately, it is possible to deactivate the brake. It is an easy modification, and it is completely reversible.
First, download the Inter 3 service manual from the Shimano website. It is a very clear and complete document which shows you around the device, and also has a complete parts list.
Remove the wheel from the bicycle, and extract the hub from the wheel. It is safe to do so; the main roller bearings have their own casings, so no bearing ball is at risk of falling off. There are two metal brake pads inside the hub, held together by a sprung ring. They can be removed by hand.
After removing the pads, you need to tighten down the centrifugally-expanding shaft unit around which the pads sat. The unit must be held together, to prevent it from expanding. A small piece of metal wire will do the job, as shown in the photo below.
If you do not tighten the expanding unit, the hub will work mostly fine; however, you will notice a small lag when engaging after free-wheeling. The lag also pops up when pedaling continuously at low-power, cruising speeds, and is ever so slightly annoying. Tightening the expanding unit makes that disappear entirely.
When reassembling the hub, you will need to tighten two locking nuts on the main shaft. The inner nut is only 3 mm thick, and is turned with a 22 mm key. Just like for any bicycle wheel hub, the two nuts must be tightened against one another at just the right position. Too close to the wheel, and the hub will not rotate nicely around the shaft; too far from the wheel, and the hub will move about slightly, eventually destroying the roller bearings (I learned this the hard way so you don’t have to). Therefore, I highly recommend you use a flat 22-mm key to hold the inner nut, and then tighten the nuts attentively. Flat keys are very inexpensive on Ebay.
Once everything is reassembled, the hub will work as before, except the rider can backpedal freely. There is no noticeable difference.
The Inter 3 hub is a really fine piece of engineering. I must grant that it is not particularly quiet (the lower gears are always freewheeling relative to the upper ones, so it it is only completely silent in first gear). However, the gears are staged just right for urban riding, the service manual is stellar, and, most importantly, the gear switching is flawless. Gears switch instantly, without pedal movement, in a swift and satisfying turn of the wrist. I’ll never go back.
The beginnings of this mahogany desk from my dad’s house are not known for sure. The wood is very likely from Cuba, which is in itself a sad story, as this entirely renewable resource was completely wiped off from the region through catastrophic mismanagement. In any case, the desk arrived in the hands of a Soviet diplomat in the island.
The diplomat must have traveled around the world, and the desk landed in the Embassy of the USSR in Brussels, Belgium. The Embassy then donated it to the Communist Youth in Brussels. The organization shared its office with the Maison de Jeunes “1917” in the city, where my father worked in the sixties and seventies. Predictably, the occupants, a large group of young, loud, opinionated people with a knack for throwing parties and hosting tasteful live music, failed to take care of it properly, and it fell into disrepair.
At some point, my father was asked to carry out electricity cabling work in the Communist Youth’s offices, where he spotted the desk. It was scratched, parts were missing, and the leather cover was torn. An arrangement was made, my dad did the work for free and walked off with the desk.
At that time, my father was gathering old and interesting furniture found in various places, and learning to restore them. Together with his partner at the time, he worked on the desk and they restored it completely. He couldn’t find new drawer handles to replace the missing ones, so he had some forged based on the existing ones at Siffleur in the city.
I was born in 1983. Shortly after, he drove down to the French Riviera, found a job, and my mother and I joined him there, starting a new life. He brought all of his cherished furniture with him, and so I have always known this desk, as well as half a dozen other pieces of furniture with similarly interesting stories. My dad always said that a good piece of wooden furniture was nicer to look at than a painting.
Last May, my dad lost all hope of recovering from of a long-term medical condition. At the time, the covid19 pandemic had just hit Europe, and my university had just switched to online teaching, so I was able to work remotely. Some airlines were operating again, so I flew down south. I brought with me a half-decent laptop, a webcam, a microphone, and a Wacom tablet, all snapped off Ebay in the weeks prior.
And so I arrived at the desk. Over the course of the following weeks, I was able to spend time with my dad in his last battle, at home, all while working: producing lecture videos, weekly quizzes, individualized peer-graded homework assignments, interactive Zoom sessions, and mostly-complete lecture notes for my course in fluid dynamics. I had the opportunity to contemplate and appreciate the many blessings which allowed me to be there. The support of my supervisor and colleagues. The love of close relatives. The patience of students. The resilience of many technological systems upon which I depended. And a blurry but strong inherited feeling for how to take life decisions and owning up to them. The desk was not particularly comfortable, and I never had time to fix the chair. But it was so fitting that I was able to work on this beautiful, solid, massive-wood piece of my father’s life.
My father passed away in June. I flew back to Germany. I miss him. I don’t know what is going to happen to the desk.
With universities massively turning to online teaching, there is a lot of discussion regarding exams, and proposals for tech-enabled, remotely proctored examinations are often propping up.
I came across this deck of slides (archive) titled “Prüfungen von zuhause aus? Geht das?” (“Exams from home? Is that possible?”), authored in May 2019 by the center for teaching and learning of the Teschnische Universität München (TUM). It is nothing short of horrifying.
There are only two instances of students in this TUM presentation: a smiling woman sitting on her bed, and a handful of cheaters.
Surely the author could have considered the reality of going through an online proctored exam for the people who are at the heart of it: the students.
I am mildly nauseated by this discussion of various deep surveillance technical systems that somehow manages not to include a discussion of ethics. Dumping it all on student consent is cheap and careless.
I’d care for a description of the potential for abuse, the risk of loss of control of data, the lack of oversight, and of the deeper human right concerns associated with giving a for-profit third party access to the most intimate aspects of people’s lives. Drew Harwell covers this well in the Washington Post this month: Mass school closures in the wake of the coronavirus are driving a new wave of student surveillance.
After that we could perhaps discuss the issue of fueling deep distrust and contempt between teachers and learners.
Instead, in this deck of slides, we are shown a totalitarian state’s dream system (face recognition, eye movement tracking, fingerprinting, type pattern analysis, remote storage of video recordings, remote control of personal devices, you name it) with flow charts that have smileys in them.
It’s not flattering for the TUM to release a document like this. We have ethics committees for things as small as pacemakers or ABS braking systems. People of TUM. Thinking of that was part of the actual homework.
Through my work as a university teacher, I am in a position where my decisions regarding technology directly involve and affect other people. With time, I have seen my views and values change.
In 2007 I was convinced that software freedoms (as incarnated by the open-source movement) were, by far, the most important ingredients of a healthy computerized society. At that time “iPhone” and “smartphone” were hardly part of our vocabulary, Amazon was an online bookstore, and Facebook had two billion users less than it has today.
Over time, I have seen that internet landscape change mostly for the worse, into a phenomenal five-company marketplace. But now, I feed that system too, and have my students, relatives and colleagues feed it with me.
The first thing that happened is that I have started doubting the free/open-source movement’s ability to enable well-functioning commercial relationships. There happens a time when the open-source, privacy-respecting, internally-hosted tool breaks down and you have no direct support line of contact to fix it. A lecture hall with 70 students in the middle of a lecture is not a good place to start debugging where the lost network packets end up — you need someone else to handle that, and a commercial contract of some kind is the best way to get help. Thus at some point three years ago I started asking myself how much learning is taking place in addition to how much personal data is harvested, when choosing software tools.
Secondly, I have come to realize that accessibility is hard. My sibling and I put an iPad in the hands of our now 97 year-old grandmother, because it is works better for her than anything else. I hate the un-rootable, un-reparable, un-upgradeable, un-recyclable design, and the pay-to-play model of the App store. And I love the human connection and sheer life experience that the device enables.
Many aspects of technology contribute to its accessibility, and the results are largely invisible to those of us who are able-bodied and financially secure. Last summer, Chris Arnade’s book about poverty in America and Haben Girma’s book about life as a deaf and blind university student greatly widened my field of view. I have also realized that lack of accessibility helps sustain our tremendous lack of diversity in the academic scientific community.
And so now, in my soon-to-be online course about fluid dynamics, I use YouTube to share videos and not a local file drop server. I understand that accessible can mean having subtitle captions available because you do not hear/understand well, or obtaining the right quality/size balance for a crappy hospital waiting room WiFi, or having the video “just work” without waiting over the occasional downtime, without installing special decoding software, without typing your password on someone else’s computer, or other hurdles that students often have to overcome.
This is not a dishearted change of philosophy. I still support the development of privacy-respecting, decentralized web services to the best of my ability. I am very proud of our new open-source, locally-run peer-graded homework program. I have simply become more careful in balancing individual liberties, the protection of privacy and intimacy, and the accessibility of my university courses.