Backward design Updated +Created
This is one of Ciro Santilli's most important principles.
Steve Jobs has a great quote about this. He's totally right on this one!
You've got to start with the customer experience and work backwards to the technology. You can't start with the technology and try to figure out where you're going to sell it.
Video 1.
Steve Jobs Insult Response excerpt from the 1997 WWDC
. Source. TODO understand the context of the question a bit better. It is something to do with an OpenDoc thing and Java.
Decide your goal first, and then do whatever is needed to how to reach it.
Don't start randomly learning tech, because that means you will waste a lot of time learning useless stuff.
There is of course some level chicken-and-egg paradox in this, as highlighted by Dilbert, since choosing an achievable goal in the first place requires some level of technical understanding.
Figure 1.
Dilbert cartoon about designing a nuclear power plant from user requirements (2002)
Source.
This cartoon illustrates well how when doing deep tech and fighting against the laws of physics, you can't just start from user requirements, but you also have to also think "what can we actually get done at all with this new technique".
The best research engineers are able to identify what is just on the cusp of the "possible", but which has the greatest value. This is the endless dance between the tech push, and the market/need pull.
However, it is much more common that people will get way too involved in learning useless stuff and lose sight of the useful end goals.
Rather, take an iterative approach:
There is some truth to the counter argument that "but if you don't spend a lot of time learning the basics, you can never find solutions".
However, these people underestimate your brain. The brain is beautiful, and human intuition is capable of generating interest towards the things that are actually useful to reach your goal. When you feel like learning something related to your goal, by all means, give yourself the time to do so. But this still be much more efficient than just learning random things that other people tell you to learn.
Bibliography:
Bacteria Updated +Created
Bacterial cellular morphogology Updated +Created
Bacterial conjugation Updated +Created
Bacterial genome Updated +Created
Bad film Updated +Created
Many bad films have good aspects. They just didn't cross the elusive threshold of a good film.
Baker-Campbell-Hausdorff formula Updated +Created
Solution for given and of:
where is the exponential map.
If we consider just real number, , but when X and Y are non-commutative, things are not so simple.
Furthermore, TODO confirm it is possible that a solution does not exist at all if and aren't sufficiently small.
This formula is likely the basis for the Lie group-Lie algebra correspondence. With it, we express the actual group operation in terms of the Lie algebra operations.
Notably, remember that a algebra over a field is just a vector space with one extra product operation defined.
Since a group is basically defined by what the group operation does to two arbitrary elements, once we have that defined via the Baker-Campbell-Hausdorff formula, we are basically done defining the group in terms of the algebra.
Banheiros da USP Updated +Created
Semi-comical student website to review the toilets of the University of São Paulo. Some of the toilets had a reputation for being terrible.
One is reminded of Crushbridge.
Bare metal Updated +Created
Bare metal programming is to run a program without an operating system below it.
Or in other words, it is basically implementing an operating system/firmware yourself ad hoc, together with your actual program.
Barton Zwiebach Updated +Created
Baryon vs meson vs lepton Updated +Created
"Barys" means "heavy" in Greek, because protons and neutrons was what made most of the mass of known ordinary matter, as opposed notably to electrons.
Baryons can be contrasted with:
Based God Updated +Created
Someone who is not a pussy.
Someone once called Ciro Santilli that: archive.is/W1ocv. It's an overstatement, considering that Ciro's parents have some money. Not infinite. But still. Changes everything. A real Based God is someone like Charles Bukowski, who had to work decades at the post office.
Bash HOWTO Updated +Created
Battlecode Updated +Created
Some mechanics:
  • inter agent communication
  • compute power is limited by limiting Java bytecode count execution per bot per cycle
Video 1.
Battlecode Final Tournament 2023
. Source.
Video 2.
Introduction to Battlecode by MIT OpenCourseWare (2014)
Source.
Battle of Algiers (1966) Updated +Created
There's nothing like seeing the hypocrisy of the "Liberté, Égalité, Fraternité" people destroyed.
Interesting how Algeria now supports China's Xinjiang policy in 2019. But of course, dictatorships tend to work together
Ciro Santilli's father, an avid history reader, and in particular interested in the military dictatorship in Brazil through which he lived, once told Ciro how the French torture doctrine was directly adopted by Brazillian military, e.g. then even invited general Paul Aussaresses who had served in Algeria, to help them out with intelligence operations and give courses. Bro, fuck that.
BB84 Updated +Created
Does not require entangled particles, unlike E91 which does.
en.wikipedia.org/w/index.php?title=Quantum_key_distribution&oldid=1079513227#BB84_protocol:_Charles_H._Bennett_and_Gilles_Brassard_(1984) explains it well. Basically:
  • Alice and Bob randomly select a measurement basis of either 90 degrees and 45 degrees for each photon
  • Alice measures each photon. There are two possible results to either measurement basis: parallel or perpendicular, representing values 0 or 1. TODO understand better: weren't the possible results supposed to be pass or non-pass? She writes down the results, and sends the (now collapsed) photons forward to Bob.
  • Bob measures the photons and writes down the results
  • Alice and Bob communicate to one another their randomly chosen measurement bases over the unencrypted classic channel.
    This channel must be authenticated to prevent man-in-the-middle. The only way to do this authentication that makes sense is to use a pre-shared key to create message authentication codes. Using public-key cryptography for a digital signature would be pointless, since the only advantage of QKD is to avoid using public-key cryptography in the first place.
  • they drop all photons for which they picked different basis. The measurements of those which were in the same basis are the key. Because they are in the same basis, their results must always be the same in an ideal system.
  • if there is an eavesdropper on the line, the results of measurements on the same basis can differ.
    Unfortunately, this can also happen due to imperfections in the system.
    Alice and Bob must decide what level of error is above the system's imperfections and implies that an attacker is listening.
BCS Theory Updated +Created
Main theory to explain Type I superconductors very successfully.
TODO can someone please just give the final predictions of BCS, and how they compare to experiments, first of all? Then derive them.
High level concepts:
Beeching cuts Updated +Created
A disaster. More cars and less trains...
Bibliograpy:
  • Losing Track by Channel 4 (1984), especially episode 5
  • www.theguardian.com/uk/2013/mar/02/beeching-wrong-about-britains-railways
    Today the makeup of UK transport looks very different from the one envisaged by Dr Beeching. Rail passenger figures have almost doubled over the past 10 years; commuter trains are crammed; young people are deserting the car for the train; and Britain's railway bosses are struggling to meet soaring demands for seats. The legacy of Beeching - dug-up lines, sold-off track beds and demolished bridges - has only hindered plans to revitalise the network, revealing the dangers of having a single, inflexible vision when planning infrastructure.
    "The crucial lesson to take from the Beeching anniversary is that you have to be flexible when planning transport infrastructure. Beeching was not," says Colin Divall, professor of rail history at York University. "Yes, many loss-making lines did need closing down, but nowhere near the number earmarked by Beeching, as we can now see with terrible hindsight."
Being naughty and creative are correlated Updated +Created
Ciro Santilli believes that there is a close link between the ability to create disruptive technology, and the desire to find bugs/exploits in systems.
Both of them destabilize society and enterprises.
Some examples:
And yes, this sometimes leads into a fine line between legality and illegality:
Being proud of low level programming is stupid Updated +Created
Ciro's word of caution for 2019 aspiring system programmers: Should you waste your life with systems programming?
This is basically a direct consequence of backward design.
The higher the level you can operate at, the better.
C is better than assembly, userland better than kernelland.
The ideal level to operate at, and one of humankind's greatest ambitions is "AGI, make me money", the highest possible level.
Only go down a level when it seems necessary.

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