robryk @robryk@qoto.org
I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work on weird ML (we'll see how it goes), am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.
I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.
If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.
I appreciate it if my grammar or style is corrected (in any of the languages I use here).
Joined Nov 2020
robryk
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robryk
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I can finally reveal some research I've been involved with over the past year or so.
We (@redford, @mrtick and I) have reverse engineered the PLC code of NEWAG Impuls EMUs. These trains were locking up for arbitrary reasons after being serviced at third-party workshops. The manufacturer argued that this was because of malpractice by these workshops, and that they should be serviced by them instead of third parti
es.
1/4
Note that https://sensors-eawag.ch/sars/overview.html has recently had very large (positive) derivatives (so much that I'm somewhat surprised not to see anything that looks to my eye as timing variation across different regions).
robryk
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robryk
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https://x.com/kayseesee/status/1725587747279380831
For people not wanting to click Twitter links:
> I am proud to present you the pre-print of our paper on GWP-ASan. 5+ years of work by four companies, spanning Server, Desktop, and Mobile, running on billions of devices. Finding and fixing thousands of bugs and potential vulnerabilities.
https://store.steampowered.com/app/497780/Recursed/ is the most Smullyan-like computer game I remember ever playing.
Why do people require signed fetch, but allow the same posts to be viewed via a web browser?
robryk
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And I've just learned that he's died last year.
So, in the spirit of making people's passing not-totally-sad (as in, it's better that they've existed and died compared to them not existing at all), some anecdotes about Dr. Włodzimierz Borkowski:
He specialized in neonatology. I don't remember how I know this, but one of the reasons for that was that he himself had joint problems that made walking over non-level surfaces hard for him that were caused by some perinatal issues.
He would treat his patients, whether young or adult, as people who should know what he's thinking. Apart from him actually answering questions of children (and not just saying something to make the child be satisfied), he'd point-blank admit when he didn't know something, or wasn't sure. (This created very polarized opinions about him among patients.)
So, something that happened at least once to my parents was that we went to see him (I don't remember what the problem was anymore, probably something related to pollen allergy); he in the end didn't have a good guess on the underlying cause, so he said so, gave some advice on symptom avoidance, asked us to try to make some observations, and to come back in 2 weeks or so. A few days later my parents got a phonecall: he thought about it in the meantime and had a new idea, that he wanted them to try.
Why do we say that batteries/energy storage is something that stores and releases energy?
A device that is able to convert some amount of heat into zero-entropy energy is ~just as useful as a battery of the same capacity. It's obvious that such a device can exist (a thermos with some amount of heat capacity inside at a temperature lower than environment + a heat engine is such a device), and it has at least one significant advantage over a battery: it is not necessarily able to release a significant quantity of energy on failure/destruction.
One can easily create such batteries in that exact way (by using a thermos and heat engine). My rough upper bound is that the highest "energy" density one could get without phase transition would be ~2MJ/kg[*] (by using gaseous hydrogen as the medium), which is a bit better than current batteries (but is an upper bound that ignores any practicalities of handling hydrogen, inefficiencies other than thermodynamically necessary, and the weight of infrastructure). I've looked at a few phase transitions (e.g. ice/water or liquid/gaseous nitrogen) and they don't seem to be able to give anything even close to the value for hydrogen (or, for that matter, mere Li-Ion batteries).
Are there other ways to store negative entropy? I imagine that chemical ones "should" exist, but I have terrible intuition for entropy changes across chemical reactions to even know where to start looking.
[*] I've taken half of the energy that would be needed to heat hydrogen from ~0K to ~room temp (half because efficiency will change linearly between 1 and 0 as the temperature of the hydrogen increases).
tl;dr Are there any better ways to store negative entropy without storing energy than storing very cold hydrogen? Is there some sort of fundamental limitation in play?
robryk
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@robryk My understanding is that the portion of the subscription that goes to the video side of the platform is split 55-creator/45-YouTube just like ad revenue.
But the real question what is that portion? And does it change whether and how much you stream music?
If YouTube actually split those services out and made this clear, I'd wager WAY more creators would be advocating for it.
robryk
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GET LAMP, the documentary I created 13 years ago, is available for free, but the GETLAMP.COM website didn't make that clear. Now it does, linking to the Internet Archive's set of .ISO files.
Ojej, właśnie się zorientowałem, że jesteście dwoma różnymi osobami ^^* (piszę, bo strzelam, że inni mogli też się podobnie mylić)
robryk
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So… I'm writing another piece of CAD software 🤓
Say hi to Dune 3D, a parametric 3D CAD that supports STEP import, chamfers and fillets!
It's the result of gluing together the UI from Horizon EDA with the solver from solvespace and Open CASCADE for a geometry kernel.
After about 3 months of off-and-on development, it's finally ready for prime time, go check it out on https://github.com/dune3d/dune3d#readme
Don't be surprised if it's a bit janky or lacks some features, there's still a lot left to be done…
Today I learned that when you edit a Mastodon post:
- the web UI allows you to look at previous versions,
- ActivityPub API doesn't seem to mention their existence.
This makes me sad, because it means that (a) there's no uniform version identifier preserved across instances that have the same post (which could help detect malfeasance) (b) custom Fedi clients are denied access to something that is exposed via the Web UI, which forces people to use the web ui (or another instance's web ui, if that instance received all the versions) instead of an APub client.
(Aside, I've also found a server that 403s on attempts to use curl's User-Agent to fetch posts from it. I'm not sure how I feel about that.)
robryk
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I just realized that `let _ = ...` and `let _foo = ...` behave differently in #rust.
The former drops the value immediately while the latter drops it at the end of the scope. This almost never matters due to the borrow checker but this was resulting in my tracing context being broken because I was calling `let _ = span.enter()` and the guard was being dropped right away.
robryk
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Wie hoch ist das Unfallrisiko auf Deiner bevorzugten Veloroute in der Stadt #Zürich?
Checke den Velounfallrisiko-Rechner dazu unter 👉 https://www.nzz.ch/zuerich/so-gefaehrlich-ist-ihre-zuercher-veloroute-ld.1749405
Chapeau @nzz -Visuals (!) Einmal mehr eine sehr gelungene #OpenData-Anwendung 👏
#ddj #velo #unfall
plpol
W międzyczasie mój znajomy zrobił ~taką symulację:
https://github.com/OnufryW/Dhondt
(Nie bierze ona pod uwagę szansy na bycie języczkiem u wagi w kontekście przekraczania progu wyborczego, bo jej głównym celem jest pokazanie różnic między okręgami.)
robryk
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IFComp 2023 begins now! https://youtu.be/bd1X9GrkCcs
I enjoy things around information theory (and data compression), complexity theory (and cryptography), read hard scifi, currently work on weird ML (we'll see how it goes), am somewhat literal minded and have approximate knowledge of random things. I like when statements have truth values, and when things can be described simply (which is not exactly the same as shortly) and yet have interesting properties.
I live in the largest city of Switzerland (and yet have cow and sheep pastures and a swimmable lake within a few hundred meters of my place :)). I speak Polish, English, German, and can understand simple Swiss German and French.
If in doubt, please err on the side of being direct with me. I very much appreciate when people tell me that I'm being inaccurate. I think that satisfying people's curiosity is the most important thing I could be doing (and usually enjoy doing it). I am normally terse in my writing and would appreciate requests to verbosify.
I appreciate it if my grammar or style is corrected (in any of the languages I use here).
Joined Nov 2020
