@JorgeStolfi@mas.to
@JorgeStolfi@mas.to avatar

JorgeStolfi

@JorgeStolfi@mas.to

Computer Science professor, State University of Campinas (UNICAMP), Brazil.

Generally leftist (which means socialist outside the US), dreaming of democracy, justice, equality, disarmament, respect for science and human life, green energy, etc.

Posts in Portuguese are about topics of mostly Brazilian interest.

This profile is from a federated server and may be incomplete. Browse more on the original instance.

JorgeStolfi, to random
@JorgeStolfi@mas.to avatar

Amy Castor and @davidgerard report on the foundations of Bitcoin security, namely your coins are not stolen if you don't know they have been stolen; on why Lithuania (no longer Estonia) is the most important EU country for crypto; on how courts have agreed to let a ponzi resume operations in order to transfer the loss of some victims to new victims -- supervised by an expert in bad investments; on what girlfriends are for; on numbers going up in Turkey; and much more: https://davidgerard.co.uk/blockchain/2023/09/18/crypto-collapse-fortress-custody-hack-binance-stonewalls-sec-ftx-to-dump-its-crypto-genesis-sues-dcg-new-york-restricts-crypto-listings/

JorgeStolfi, to random
@JorgeStolfi@mas.to avatar

Amy Castor and @davidgerard report on the bright just past future of AI and their rather less bright present future.

Including ChatGPT now recursively training itself (still with a human in the loop, but he is a Kenyan paid pittance per hour so he does not count).

Including Google's curious policy re use of its own AI-based programming assistant by its own programmers.

Including how "AI" has become the new "Blockchain" for Wall Street purposes.

And more...

https://amycastor.com/2023/09/12/pivot-to-ai-pay-no-attention-to-the-man-behind-the-curtain/

JorgeStolfi, to random
@JorgeStolfi@mas.to avatar

Amy Castor and @davidgerard report on how bitcoin let the Mob replace the classical suitcase full of money by a suitcase full of another thing; on the next Signature Bank; on PayPal's coin that's not just stable, but downright immobile; on the US gov hoarding child porn; on why crooks should try to be succinct; on how to make good on IOUs with IOUs; on how BTC miners are avoiding burning coal; on teaching poor Salvadoreans to give money to scammers. All in great detail. https://davidgerard.co.uk/blockchain/2023/09/04/crypto-collapse-tethers-new-bank-britannia-binance-woes-nobody-uses-paypals-stablecoin-avi-eisenberg-is-not-getting-his-phones-back/

JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

"She'll be coming round the mountain, when she comes, [2x]
She'll be coming round the mountain, [3x]
When? Don't ask."


JorgeStolfi, to HashtagGames
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Because if you pick up the phone and say"sorry, I am not home right now" the caller may perhaps suspect that you are lying.


overholt, to random
@overholt@glammr.us avatar

The oldest printed book in the Huntington Library isn’t its Gutenberg Bible, but a Chinese Buddhist text nearly four centuries older. https://huntington.org/videos-and-recorded-programs/thousand-years-books-printed-1085

JorgeStolfi,
@JorgeStolfi@mas.to avatar

@overholt

Gutemberg did not invent printing, which had been in use for many decades in Europe. He invented (for Europe) the printing with a separate stamp for each letter, the stamps being assembled into a page stamp.

I gather that the Chinese book shown in the link was printed, but with a single wood block carved anew for each page. Isn't that so?

JorgeStolfi,
@JorgeStolfi@mas.to avatar

@zdl @yassin @overholt

There is even a word for books that were printed in Europe before Gutenberg, with one engraved copper plate or carved wood block per page. E.g. https://en.wikipedia.org/wiki/Hypnerotomachia_Poliphili

JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

"An apple a day keeps the samsung away"


JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

"Render unto Caesar the salad which is Caesar's"


JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

"You were looking for Carmen Sandiego? Here I am. And this is my travel companion, Waldo. What can we do for you?"


JorgeStolfi, to HashtagGames
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"There are much more important things in life than money, Donald. Especially for a duck. Heed this advice from your old uncle."


JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

Humpty Dumpty sat on a sofa.


JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

Hannibal Lecter, vegan.


JorgeStolfi, to SpaceX
@JorgeStolfi@mas.to avatar

SpaceX said that the second test of Starship's Super Heavy Booster lasted the full planned 6 seconds and all engines lit up (at half-power) but two shut down prematurely.

However, the video of the test shows ignition at about 5:23 seconds and shutdown before 5:27 seconds. Another "Musk Approximaiton"?

https://www.youtube.com/watch?v=kUPEvJqfuzU&t=323s

JorgeStolfi,
@JorgeStolfi@mas.to avatar

@glitzersachen

It is possible, yes. To them that may count as "6 seconds".

JorgeStolfi, to random
@JorgeStolfi@mas.to avatar

The Secret Service claimed that all their messages sent on Jan/6 had been permanently and completely erased from all their phones.

But that was before they handed over those millions of "documents" to Jack Smith's grand jury, wasn't it? Have they miraculously found those deleted phone messages?

johncarlosbaez, (edited ) to random
@johncarlosbaez@mathstodon.xyz avatar

Musical tuning systems is the subject where you get mad at irrational numbers. Nothing works perfectly - and it's not your fault: it's math's fault. It's all about pushing around lumps in the carpet.

An 'octave' is the chord where the high note vibrates 2 times as fast as the low note. In a 'perfect fifth' it vibrates 3/2 times as fast. In a 'perfect fourth' it vibrates 4/3 as fast. In a 'major third' it vibrates 5/4 as fast. Our ears love these simple fractions.

But if you go up 4 perfect fifths, it's not quite the same as going up 2 octaves and a major third, since

3/2 × 3/2 × 3/2 × 3/2 = 81/16

is not quite

2 × 2 × 5/4 = 5 = 80/16

AARGH! 😠

The difference between these is called the 'syntonic comma'. Well, actually the ratio

81/80 = 1.0125

is called the syntonic comma. Listen to two notes with this frequency ratio:

https://en.wikipedia.org/wiki/Syntonic_comma

You can hear they aren't in tune, and it probably sounds annoying. This is why we can't have nice things.

Another problem is that if you go up 7 octaves it's almost but not quite 12 perfect fifths, since

2⁷ = 128

is not

(3/2)¹² = 129.746337890625

The ratio of these is called the 'Pythagorean comma':

531441/524288 = 1.0136432647705078125

This is why a 12-tone scale with all the notes equally spaced can't have perfect fifths. But for vocal music, the syntonic comma is more urgent problem, since it involves simpler fractions. It shows up in lots of different ways: two people can sing two different parts starting in tune, each singing beautifully, and wind up out of tune.

JorgeStolfi,
@JorgeStolfi@mas.to avatar

@johncarlosbaez

Most likely the ear likes notes in simple frequency ratios because it interprets them as harmonics of a "dirty" periodic sounds whose fundamental is not heard because it is too low or suppressed. For example, the 4:5 chord is the 4th and 5th harmonics of a much lower note.

Many physical processes generate "dirty" periodic or quasi-periodic sounds, so detecting patterns of harmonics has obvious survival value in interpreting the sound signal that is heard. 🧵‍>

JorgeStolfi, to HashtagGames
@JorgeStolfi@mas.to avatar

Be spared from watching the latest stupid Hollywood blockbuster, because the TVs on the seats stopped working in 1998.


Teri_Kanefield, to random

deleted_by_author

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    JorgeStolfi,
    @JorgeStolfi@mas.to avatar

    @Teri_Kanefield @JamesGleick

    Can you give an example of a situation for which the Act would make sense?

    I imagine it would be, for instance, when an FBI agent steps on a flowerbed while arresting the son of a Governor, and is charged with vandalism by his State prosecutor. Is that the idea?

    jrenken, to random
    @jrenken@mastodon.sandwich.net avatar

    It’s broken record time again: We desperately need to do better at teaching ethics to people in STEM.

    I’ve just reported an LLM project to the platforms it uses, as an imminent threat to life. It “enables a user to have an interactive dialogue about medical conditions, symptoms…” with ChatGPT.

    It does NOT MATTER how many disclaimers you put in front of that. It is an imminent threat to life, and you will not implement it.

    JorgeStolfi,
    @JorgeStolfi@mas.to avatar

    @jrenken

    What good those ethics courses can do? It is like forcing prisoners to listen to Bible sermons.

    The only way to get tech professionals to consider ethics when developing their products is to punish them promptly and severely when they fail to do it.

    GossiTheDog, to random
    @GossiTheDog@cyberplace.social avatar

    deleted_by_author

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    JorgeStolfi,
    @JorgeStolfi@mas.to avatar

    @GossiTheDog

    I wonder who were the other 6 passengers.

    JorgeStolfi, to HashtagGames
    @JorgeStolfi@mas.to avatar

    lucky kids could get a chemistry kit with interesting chemicals like ammonia, lead nitrate, cobalt chloride, etc. And an alcohol lamp.

    Today parents will not mind much if their kids enter motocross races or take up smoking. But touch "toxic chemicals", oh horror...

    JorgeStolfi, to HashtagGames
    @JorgeStolfi@mas.to avatar

    , you could tell how many transistors there were in the CPU of your computer by opening the cabinet and counting them.

    JorgeStolfi, to HashtagGames
    @JorgeStolfi@mas.to avatar

    , one could distinguish a nerd from boring normal people by the handful of colored pens sticking out of the shirt pocket.

    And one could distinguish an engineer from inferior minds by the slide rule sticking out of that same pocket instead.

    JorgeStolfi, to HashtagGames
    @JorgeStolfi@mas.to avatar


    Back in my day I would leave the data processing bureau where I worked, in downtown São Paulo, at 3:00 am, and walk some 15 km to my home out in the city suburbs, just to unwind and relax.

    Today, some people think that walking 15 meters on the street at 03:00 pm is too risky...

    [serious]

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