henrikeh

7 ms·

1. 1.▲
   by henrikeh 6mo ago

   While some comments do point out the general opaqueness of Mathematica, the goal of Simplify is actually documented in Mathematica and something which can be changed: https://reference.wolfram.com/language/ref/Comp
2. 2.▲
   by henrikeh 2y ago

   I think Mathematica’s documentation is beyond excellent. Here is the documentation for the Flatten function: https://reference.wolfram.com/language/ref/Flatten.html Just look at the amount of examples and details
3. 3.▲
   by henrikeh 2y ago

   I don’t know about this cable specifically, but it can be done by transferring more power to the optical signal. Erbium-doped fiber amplifiers work by utilizing a nonlinear optical effect where energy is transferred from a pump laser to the
4. 4.▲
   by henrikeh 4y ago

   > I used to work at a hedge fund known for its diagnosis process, a logical process of clearly defining the suboptimal outcome that occurred, agreeing on how it should have gone and what had happened, and if it's indeed wrong to hav
5. 5.▲
   by henrikeh 4y ago

   Ada / SPARK can do that. Ada has had some form of that analyses since the first version from 1983. https://learn.adacore.com/courses/intro-to-spark/chapters/03...
6. 6.▲
   by henrikeh 4y ago

   We used constellation shaping and a rate adaptive code to tailor tailor the bitrate of each channel. It varied between something along 64-QAM and 256-QAM depending on the SNR in the channel. Post processing times were not too bad. It ran on
7. 7.▲
   by henrikeh 4y ago

   Thanks :-) It is a while since I have been into optical signal processing, but I will ask my colleague who is much more well-versed.
8. 8.▲
   by henrikeh 4y ago

   I must confess that I have never been concerned along those lines. I have thought a lot more about the environmental impact of transmission technology. It is a massively energy consuming industry and the expectation is to provide more capac
9. 9.▲
   by henrikeh 4y ago

   I worked on this project and cycomanic summarizes the practice well. I’ve written more on it here: https://news.ycombinator.com/item?id=33321506
10. 10.▲
    by henrikeh 4y ago

    I should clarify that we did measure every channel (polarization, wavelength and fiber core) individually. It would not be fair if we just measured one and multiplied ;) (And yes, that took forever. A shout out to A. A. Jørgensen and D. Kon
11. 11.▲
    by henrikeh 4y ago

    Wrote another reply here: https://news.ycombinator.com/item?id=33321669 I’d say that there is at least a 10 year delay between the lab and commercial deployment. Even then we are talking about deployment in large fiber syst
12. 12.▲
    by henrikeh 4y ago

    I can’t answer for the chip aspect (which is the truly novel part of this research), but many of the signal processing and coding techniques are being deployed in new optical transmission systems. Constellation shaping and rate adaptive co
13. 13.▲
    by henrikeh 4y ago

    Thanks! I’ve reached out to my colleague who worked on the chip side of this project.
14. 14.▲
    by henrikeh 4y ago

    The two other comments gave very good general answers, but I happen to have worked on this specific project, so I can give some very specific details (as far as my memory goes.) Lab testing of this scale of transmission involves a bit of “e
15. 15.▲
    by henrikeh 4y ago

    The chip which produced the laser is indeed “just” CW with data modulated on separately. And novelty indeed lies in the width of the comb source and the SNRs of the obtained channels. (Worked on this project.)
16. 16.▲
    by henrikeh 4y ago

    Late to the thread, but I took part of this research (7th author in the list). I worked on the signal processing, information coding etc and is happy to answer any questions :-)
17. 17.▲
    by henrikeh 4y ago

    Cell phone cells are (ideally) shaped to account for the expected pattern of how handover will occur. Along roads and train lines, the cells are (at least in GSM) supposed to be tailored to allow for easy routing and handover as the devices
18. 18.▲
    by henrikeh 4y ago

    The article gives a few examples where a pseudo-class fits better with how CSS normally works. For example, the selector matches the last item in the selector. With ‘<‘ it would match ‘parent’ in your case. You can also match descendants
19. 19.▲
    by henrikeh 4y ago

    I do plan to write about the overall experience, but for now I keep a diary in the repo.
20. 20.▲
    by henrikeh 4y ago

    I have been reading it and implementing the interpreter in Ada to learn about both interpreters and Ada better. It is a wonderful way to learn, since I constantly have to go beyond the surface level. What is the purpose of this and that in
21. 21.▲
    by henrikeh 4y ago

    In Denmark, so not the same as who you reply to. Yes, if you pay too much in tax and their calculations reveal that, then, yes, you get money back on your bank account. They don’t calculate commute deductibles for you, but mortgages, pensio
22. 22.▲
    by henrikeh 5y ago

    Do you have any sources on that? I can not find anything about those interacting or Perelman saying that he does not care about the axioms of his work.
23. 23.▲
    by henrikeh 5y ago

    At least not in the ones tested in the video. Also, the prewash happens in a cycle, where the soap holder isn’t opened.
24. 24.▲
    by henrikeh 5y ago

    Well, since you ask. `git add -i` has different "escape"/"exit" semantics for different actions. If I want to quit/escape adding a patch in the interactive mode I type `q` and then enter. If I want to quit&#x2F
25. 25.▲
    by henrikeh 5y ago

    Here in Denmark we don’t, so most people have a passport.
26. 26.▲
    by henrikeh 5y ago

    Verilog is weakly typed and VHDL is strong. That is already a pretty big deal when dealing with vector signals, where Verilog happily assigns a 32-bit signal to a 16-bit signal. VHDL also supports defining record types, such that a collecti
27. 27.▲
    by henrikeh 5y ago

    Discrete Fourier Transform is probably the most accurate way to describe the mathematical transformation which is being applied. Albeit it is very popular to say FFT when what is meant is Fourier transform or DFT, it is a bit like talking a
28. 28.▲
    by henrikeh 5y ago

    Ada doesn't use the "dot syntax"; instead the enumeration literal is written as is without a dot. If I write: type Number_System is (Bin, Dec, Oct); type Month is (Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, N
29. 29.▲
    by henrikeh 5y ago

    Fwiw, Ada does this too.
30. 30.▲
    by henrikeh 5y ago

    Haskell and Ada have very different goals. Ada is designed, in part, to work on embedded and real-time systems. It isn’t really an “attempt” either. The language exists and is used and has developed as experience was gained. Why bother wit