game-icons.net Updated +Created
This is a good project. Limited scope to 2D card-like games, but very good within that scope.
Ciro Santilli used it for the 2D version of his Ciro's 2D reinforcement learning games.
Gallium arsenide vs silicon Updated +Created
The Supermen: The Story of Seymour Cray by Charles J. Murray (1997) page 4 mentions:
Cray wanted his new machine to employ circuits made from a material called gallium arsenide. Gallium arsenide had achieved limited success, particularly in satellite communications and military electronics. But no one had succeeded with it in anything so complicated as a computer. In the computer industry, engineers had developed a saying: "Gallium arsenide is the technology of the future," they would say. "And it always will be."
ExpertRank Updated +Created
Was adopted by AskJeeves in 2001.
The Google Story Chapter 11. "The Google Economy" comments:
As they saw it, generation one was AltaVista, generation two was Google, and generation three was Teoma, or what Ask Jeeves came to refer to as Expert Rank. Teoma's technology involved mathematical formulas and calculations that went beyond Google's PageRank system, which was based on popularity. In fact, the concept had been cited in the original Stanford University paper written by Sergey Brin and Larry Page as one of the methods that could be used to rank indexed Web sites in response to search requests. "They called their method global popularity and they called this method local popularity, meaning you look more granularly at the Web and see who the authoritative sources are," Lanzone said. He said Brin an Page had concluded that local popularity would be exceedingly difficult to execute well, because either it would require too much processing power to do it in real time or it would take too long.
googlesystem.blogspot.com/2006/03/expertrank-authoritative-search.html mentions
ExpertRank is an evolution of IBM's CLEVER project, a search engine that never made it to public.
and:
The difference between PageRank and ExpertRank is that for ExpertRank the quality of the page is important and that quality is not absolute, but it's relative to a subject.
There are other more recent algorithms with similar names, and are prehaps related:
User mode emulation Updated +Created
User mode emulation refers to the ability of certain emulators to emulate userland code running on top of a specific operating system, usually Linux.
For example, QEMU allows you to run a variety of userland ELF programs directly on it, without an underlying Linux kernel running.
User mode emulation is achieved by implementing System calls and special filesystems such as /dev manually on the emulator one by one.
The general tradeoff is that simulation is less acurate as it may lack certain highly advanced kernel functionality you haven't implemented yet. But it is much easier to run executables with it, and you don't have to wait for boot to finish before running, you just run executables directly from the command line.
Quantum Field Theory book by Mark Srednicki (2006) Updated +Created
Author affiliation: University of California, Santa Barbara.
Number of pages: 616!
Don't redistribute clause, and final version by Cambridge University Press, alas, so corrections will never be merged back: web.physics.ucsb.edu/~mark/qft.html. But at least he's collecing erratas for the published (and therefore draft) versions there.
The book is top-level organized in spin 0, spin half, and spin 1. Quite ominous, really.
The preface states that one of its pedagogical philosophies is to "Illustration of the basic concepts with the simplest examples.", so maybe there is hope after all.
Set (mathematics) Updated +Created
Intuitively: unordered container where all the values are unique, just like C++ std::set.
More precisely for set theory formalization of mathematics:
  • everything is a set, including the elements of sets
  • string manipulation wise:
    • {} is an empty set. The natural number 0 is defined as {} as well.
    • {{}} is a set that contains an empty set
    • {{}, {{}}} is a set that contains two sets: {} and {{}}
    • {{}, {}} is not well formed, because it contains {} twice
Energy Updated +Created
Prize Updated +Created
Generally, prizes that pay big lumps of money to well established individuals are a bit useless, it would be better to pay smaller sums to struggling beginners in the field, of which there are aplenty.
The most important part about prizes should not be the money, nor the recognition, but rather explaining better what the laureates did. In this, most prizes fail. Thus Ciro Santilli's project idea: Project to explain each Nobel Prize better.
Ciro's Edict #8 Updated +Created
This month included several exciting extremelly user visible web developments.
I can't help to feel how the speed of developments reflects my relative mastery of the stack, I'm very happy about how it went.
P51 hardware Updated +Created
lspci
output:
00:00.0 Host bridge: Intel Corporation Xeon E3-1200 v6/7th Gen Core Processor Host Bridge/DRAM Registers (rev 05)
00:01.0 PCI bridge: Intel Corporation 6th-10th Gen Core Processor PCIe Controller (x16) (rev 05)
00:08.0 System peripheral: Intel Corporation Xeon E3-1200 v5/v6 / E3-1500 v5 / 6th/7th/8th Gen Core Processor Gaussian Mixture Model
00:14.0 USB controller: Intel Corporation 100 Series/C230 Series Chipset Family USB 3.0 xHCI Controller (rev 31)
00:14.2 Signal processing controller: Intel Corporation 100 Series/C230 Series Chipset Family Thermal Subsystem (rev 31)
00:15.0 Signal processing controller: Intel Corporation 100 Series/C230 Series Chipset Family Serial IO I2C Controller #0 (rev 31)
00:16.0 Communication controller: Intel Corporation 100 Series/C230 Series Chipset Family MEI Controller #1 (rev 31)
00:17.0 SATA controller: Intel Corporation Q170/Q150/B150/H170/H110/Z170/CM236 Chipset SATA Controller [AHCI Mode] (rev 31)
00:1c.0 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #1 (rev f1)
00:1c.2 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #3 (rev f1)
00:1c.4 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #5 (rev f1)
00:1d.0 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #9 (rev f1)
00:1d.4 PCI bridge: Intel Corporation 100 Series/C230 Series Chipset Family PCI Express Root Port #13 (rev f1)
00:1f.0 ISA bridge: Intel Corporation CM238 Chipset LPC/eSPI Controller (rev 31)
00:1f.2 Memory controller: Intel Corporation 100 Series/C230 Series Chipset Family Power Management Controller (rev 31)
00:1f.3 Audio device: Intel Corporation CM238 HD Audio Controller (rev 31)
00:1f.4 SMBus: Intel Corporation 100 Series/C230 Series Chipset Family SMBus (rev 31)
00:1f.6 Ethernet controller: Intel Corporation Ethernet Connection (5) I219-LM (rev 31)
01:00.0 VGA compatible controller: NVIDIA Corporation GM107GLM [Quadro M1200 Mobile] (rev a2)
01:00.1 Audio device: NVIDIA Corporation GM107 High Definition Audio Controller [GeForce 940MX] (rev a1)
04:00.0 Network controller: Intel Corporation Wireless 8265 / 8275 (rev 78)
3e:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller SM981/PM981/PM983
3f:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader (rev 01)
lspci -t
output:
-[0000:00]-+-00.0
           +-00.2
           +-01.0
           +-02.0
           +-02.1-[01]----00.0
           +-02.2-[02]----00.0
           +-02.4-[03]----00.0
           +-03.0
           +-04.0
           +-04.1-[04-63]--
           +-08.0
           +-08.1-[64]--+-00.0
           |            +-00.1
           |            +-00.2
           |            +-00.3
           |            +-00.4
           |            +-00.5
           |            \-00.6
           +-08.2-[65]--+-00.0
           |            \-00.1
           +-08.3-[66]--+-00.0
           |            +-00.3
           |            +-00.4
           |            \-00.6
           +-14.0
           +-14.3
           +-18.0
           +-18.1
           +-18.2
           +-18.3
           +-18.4
           +-18.5
           +-18.6
           \-18.7
Gauge symmetry Updated +Created
Video 1.
Lawrence Krauss explains Gauge symmetry by Joe Rogan (2017)
Source.
While most of this is useless as you would expect from the channel, it does give one key idea: you can change charge locally, but things somehow still work out.
And this has something to do with the general intuition of special relativity that only local measures make much sense, as evidenced by Einstein synchronization.
RSA (cryptosystem) Updated +Created
Based on the fact that we don't have a P algorithm for integer factorization as of 2020. But nor proof that one does not exist!
The private key is made of two randomly generated prime numbers: and . How such large primes are found: how large primes are found for RSA.
The public key is made of:
  • n = p*q
  • a randomly chosen integer exponent between 1 and e_max = lcm(p -1, q -1), where lcm is the Least common multiple
Given a plaintext message m, the encrypted ciphertext version is:
c = m^e mod n
This operation is called modular exponentiation can be calculated efficiently with the Extended Euclidean algorithm.
The inverse operation of finding the private m from the public c, e and is however believed to be a hard problem without knowing the factors of n.
However, if we know the private p and q, we can solve the problem. As follows.
First we calculate the modular multiplicative inverse. TODO continue.
2012 Internet Census icmp_ping Updated +Created
Let's check relevancy of known hits:
grep -e '208.254.40' -e '208.254.42' 208 | tee 208hits
Output:
208.254.40.95	1355564700	unreachable
208.254.40.95	1355622300	unreachable
208.254.40.96	1334537100	alive, 36342
208.254.40.96	1335269700	alive, 17586

..

208.254.40.127	1355562900	alive, 35023
208.254.40.127	1355593500	alive, 59866
208.254.40.128	1334609100	unreachable
208.254.40.128	1334708100	alive from 208.254.32.214, 43358
208.254.40.128	1336596300	unreachable
The rest of 208 is mostly unreachable.
208.254.42.191	1335294900	unreachable
...
208.254.42.191	1344737700	unreachable
208.254.42.191	1345574700	Icmp Error: 0,ICMP Network Unreachable, from 63.111.123.26 
208.254.42.191	1346166900	unreachable
...
208.254.42.191	1355665500	unreachable
208.254.42.192	1334625300	alive, 6672
...
208.254.42.192	1355658300	alive, 57412
208.254.42.193	1334677500	alive, 28985
208.254.42.193	1336524300	unreachable
208.254.42.193	1344447900	alive, 8934
208.254.42.193	1344613500	alive, 24037
208.254.42.193	1344806100	alive, 20410
208.254.42.193	1345162500	alive, 10177
...
208.254.42.223	1336590900	alive, 23284
...
208.254.42.223	1355555700	alive, 58841
208.254.42.224	1334607300	Icmp Type: 11,ICMP Time Exceeded, from 65.214.56.142 
208.254.42.224	1334681100	Icmp Type: 11,ICMP Time Exceeded, from 65.214.56.142 
208.254.42.224	1336563900	Icmp Type: 11,ICMP Time Exceeded, from 65.214.56.142 
208.254.42.224	1344451500	Icmp Type: 11,ICMP Time Exceeded, from 65.214.56.138 
208.254.42.224	1344566700	unreachable
208.254.42.224	1344762900	unreachable
Let's try with 66. First there way too much data, 9 GB, let's cut it down:
n=66
time awk '$3~/^alive,/ { print $1 }' $n | uniq -c | sed -r 's/^ +//;s/ /,/' | tee $n-up-uniq-c
OK down to 45 MB, now we can work.
grep -e '66.45.179' -e '66.104.169' -e '66.104.173' -e '66.104.175' -e '66.175.106' '66-alive-uniq-c' | tee 66hits
Nah, it's full of holes:
4,66.45.179.187
12,66.45.179.188
2,66.45.179.197
1,66.45.179.202
2,66.45.179.205
2,66.45.179.206
1,66.45.179.207
won't be able to find new ranges here.
MathDoctorBob Updated +Created
He got so old from 2012 to 2021 :-)
This dude did well. If only he had written a hyperlinked wiki rather than making videos! It would allow people to jump in at any point and just click back. It would be Godlike.
mathdoctorbob.org/About.html says:
Robert Donley received his doctorate in Mathematics from Stony Brook University and has over two decades of teaching experience at the high school, undergraduate, and graduate levels.
Craig Venter Updated +Created
One of the biotechnology superstars of the 2000's/2010's.
Generalized Poincaré conjecture Updated +Created
There are two cases:
  • (topological) manifolds
  • differential manifolds
Questions: are all compact manifolds / differential manifolds homotopic / diffeomorphic to the sphere in that dimension?
  • for topological manifolds: this is a generalization of the Poincaré conjecture.
    Original problem posed, for topological manifolds.
    Last to be proven, only the 4-differential manifold case missing as of 2013.
    Even the truth for all was proven in the 60's!
    Why is low dimension harder than high dimension?? Surprise!
    AKA: classification of compact 3-manifolds. The result turned out to be even simpler than compact 2-manifolds: there is only one, and it is equal to the 3-sphere.
    For dimension two, we know there are infinitely many: classification of closed surfaces
  • for differential manifolds:
    Not true in general. First counter example is . Surprise: what is special about the number 7!?
    Counter examples are called exotic spheres.
    Totally unpredictable count table:
    Dimension | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |Smooth types | 1 | 1 | 1 | ? | 1 | 1 | 28 | 2 | 8 | 6 | 992 | 1 | 3 | 2 | 16256 | 2 | 16 | 16 | 523264 | 24 | is an open problem, there could even be infinitely many. Again, why are things more complicated in lower dimensions??
Generalized coordinate Updated +Created
The variables of the Lagrangian, e.g. the angles of a double pendulum. From that example it is clear that these variables don't need to be simple things like cartesian coordinates or polar coordinates (although these tend to be the overwhelming majority of simple case encountered): any way to describe the system is perfectly valid.
In quantum field theory, those variables are actually fields.

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