yolov5-pip Updated 2025-07-16
OK, now we're talking, two liner and you get a window showing bounding box object detection from your webcam feed!The accuracy is crap for anything but people. But still. Well done. Tested on Ubuntu 22.10, P51.
python -m pip install -U yolov5==7.0.9
yolov5 detect --source 0 What happens to the definition of the orthogonal group if we choose other types of symmetric bilinear forms Updated 2025-07-16
We looking at the definition the orthogonal group is the group of all matrices that preserve the dot product, we notice that the dot product is one example of positive definite symmetric bilinear form, which in turn can also be represented by a matrix as shown at: Section "Matrix representation of a symmetric bilinear form".
By looking at this more general point of view, we could ask ourselves what happens to the group if instead of the dot product we took a more general bilinear form, e.g.:The answers to those questions are given by the Sylvester's law of inertia at Section "All indefinite orthogonal groups of matrices of equal metric signature are isomorphic".
- : another positive definite symmetric bilinear form such as ?
- what if we drop the positive definite requirement, e.g. ?
What poor countries have to do to get richer Updated 2025-07-16
Like all poor countries, Brazil's lack of money and scientific culture severely limit its ability to make technological and scientific advances.
While this sounds obvious, Ciro Santilli has felt it first hand since he moved from Brazil to Europe, and it is just shocking.
WhatsApp Updated 2025-07-16
Claimed to remove metadata from servers unless legally obliged to collect it: www.quora.com/Does-WhatsApp-store-messages-on-its-servers-or-is-all-deleted-after-delivery-and-only-stored-on-recipients-phones/answer/Ciro-Santilli
They claim to delete metadata: www.quora.com/Does-WhatsApp-store-messages-on-its-servers-or-is-all-deleted-after-delivery-and-only-stored-on-recipients-phones/answer/Ciro-Santilli
Circuit-based quantum computer Updated 2025-07-16
Fabless semiconductor company Updated 2025-07-16
CIA 2010 covert communication websites Breakthroughs Updated 2025-07-16
Some less-trivial breakthroughs:
- finding 2013 DNS Census
- CGI comms characterization
- secure subdomain search on 2013 DNS Census let to a few hits
- 2013 DNS Census virtual host cleanup heuristic keyword searches was massive and led to many new ranges
Software license that starts closed and becomes open once a certain amount of money is raised Updated 2025-07-16
This is an interesting licensing model that might just scale.
Software with bad user interface Updated 2025-07-16
Stockfish CLI Updated 2025-10-14
Most of what follows is part of the Universal Chess Interface. Tested on Ubuntu 22.10, Stockfish 14.1.
After starting Sweet ASCII art. where:
stockfish on the command line, d (presumably display) contains: +---+---+---+---+---+---+---+---+
| r | n | b | q | k | b | n | r | 8
+---+---+---+---+---+---+---+---+
| p | p | p | p | p | p | p | p | 7
+---+---+---+---+---+---+---+---+
| | | | | | | | | 6
+---+---+---+---+---+---+---+---+
| | | | | | | | | 5
+---+---+---+---+---+---+---+---+
| | | | | | | | | 4
+---+---+---+---+---+---+---+---+
| | | | | | | | | 3
+---+---+---+---+---+---+---+---+
| P | P | P | P | P | P | P | P | 2
+---+---+---+---+---+---+---+---+
| R | N | B | Q | K | B | N | R | 1
+---+---+---+---+---+---+---+---+
a b c d e f g h
Fen: rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1
Key: 8F8F01D4562F59FBFen: FEN notationKey: TODO
Move white king's pawn from e2 to e4:Then display again:gives:so we see that the pawn moved.
position startpos moves e2e4d +---+---+---+---+---+---+---+---+
| r | n | b | q | k | b | n | r | 8
+---+---+---+---+---+---+---+---+
| p | p | p | p | p | p | p | p | 7
+---+---+---+---+---+---+---+---+
| | | | | | | | | 6
+---+---+---+---+---+---+---+---+
| | | | | | | | | 5
+---+---+---+---+---+---+---+---+
| | | | | P | | | | 4
+---+---+---+---+---+---+---+---+
| | | | | | | | | 3
+---+---+---+---+---+---+---+---+
| P | P | P | P | | P | P | P | 2
+---+---+---+---+---+---+---+---+
| R | N | B | Q | K | B | N | R | 1
+---+---+---+---+---+---+---+---+
a b c d e f g h
Fen: rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1
Key: B46022469E3DD31BNow let's make Stockfish think for one second what is the next best move for black:gives as the last line:TODO:
go movetime 1000bestmove c7c5 ponder g1f3- what is ponder? Something to do with thinking on the opponent's turn: permanent brain.
- understand the previous lines
To make the move it as suggested for black, we have to either repeat the entire sequence of movements:or alternatively we could also use the previous FEN notation as a starting point;Note how the Universal Chess Interface interface is very simple: we just load a state and then decide what to do next for that one state. The engine holds only one and exactly one state at a time, and you can't even modify it differentially without loading new one from scratch.
position startpos moves e2e4 c7c5d: +---+---+---+---+---+---+---+---+
| r | n | b | q | k | b | n | r | 8
+---+---+---+---+---+---+---+---+
| p | p | | p | p | p | p | p | 7
+---+---+---+---+---+---+---+---+
| | | | | | | | | 6
+---+---+---+---+---+---+---+---+
| | | p | | | | | | 5
+---+---+---+---+---+---+---+---+
| | | | | P | | | | 4
+---+---+---+---+---+---+---+---+
| | | | | | | | | 3
+---+---+---+---+---+---+---+---+
| P | P | P | P | | P | P | P | 2
+---+---+---+---+---+---+---+---+
| R | N | B | Q | K | B | N | R | 1
+---+---+---+---+---+---+---+---+
a b c d e f g h
Fen: rnbqkbnr/pp1ppppp/8/2p5/4P3/8/PPPP1PPP/RNBQKBNR w KQkq - 0 2
Key: 4CA78BCE9C2980B0position fen rnbqkbnr/pppppppp/8/8/4P3/8/PPPP1PPP/RNBQKBNR b KQkq - 0 1 moves c7c5 Bitcoin script Updated 2025-07-16
bit gold Updated 2025-07-16
2017 Nobel Prize in Chemistry Updated 2025-07-16
Cryogenic electron microscopy, which was developed in the 70's.
1973 Nobel Prize in Physics Updated 2025-07-16
Black holes nearest to the Sun Updated 2025-07-16
Interesting to note that there are quite a few nearer than Sagittarius A, as of 2022 we know of one at 1.5 kly: universemagazine.com/en/discovered-the-closest-black-hole-to-the-sun/
It is interesting that a few months earlier there seemed to be no known specific black holes in the Milky Way: www.nasa.gov/feature/goddard/2022/hubble-determines-mass-of-isolated-black-hole-roaming-our-milky-way-galaxy although their count is estimated to be in the hundreds of millions.
Phaser.js Updated 2025-07-16
Likely the best JavaScript 2D game engine as of 2023.Uses Matter.js as a physics engine if enabled. There's also an alternative (in-house?) "arcade" engine: photonstorm.github.io/phaser3-docs/Phaser.Physics.Arcade.ArcadePhysics.html but it appears to be simpler/less robust (but also possibly faster).
- github.com/photonstorm/phaser
- phaser.io/
- phaser.io/examples/v3.85.0/games contains the demo games
Phase transition Updated 2025-07-16
TODO can anything interesting and deep be said about "why phase transition happens?" physics.stackexchange.com/questions/29128/what-causes-a-phase-transition on Physics Stack Exchange
Photoelectric effect Updated 2025-07-16
No matter how hight the wave intensity, if it the frequency is small, no photons are removed from the material.
This is different from classic waves where energy is proportional to intensity, and coherent with the existence of photons and the Planck-Einstein relation.
Photoelectric effect by UCSB Physics Lecture Demonstrations (2021)
Source. Stone garden Updated 2025-07-16
The literal Chinese name says it all: "Fake Mountain". The stones evoke the feeling of the beautiful rock mountains of China.
The term "奇石假山" (qi2 shi2 jia3 shan1, lit. "weird shaped stone fake mountain") is also used, almost as a synonym by many people, since the stones are often chose in interesting shapes. Choosing the right stone is basically an art form in itself.
The stones used are generally limestone, which as a sedimentary rock is weaker, and more likely to be eroded into interesting shapes.
SuperCollider Updated 2025-07-16
How to play scores and save them to files is discussed at: doc.sccode.org/Guides/Non-Realtime-Synthesis.html
They have a nice looking IDE, but running anything from the command-line interface is super hard, much unlike Csound. How to get a decent hello world: stackoverflow.com/questions/65360414/how-to-play-a-supercollider-file-non-interactively-from-the-terminal-command-lin
Sample composition with custom synths + notes: sccode.org/1-5cl
leanpub.com/ScoringSound looks like a decent tutorial, it is basically the Csound FLOSS manual for SuperCollider.
Unlisted articles are being shown, click here to show only listed articles.