NeuroSky is a company that specializes in the development of brainwave monitoring technology and applications. Founded in 2004, NeuroSky focuses on creating consumer and medical devices that utilize electroencephalography (EEG) to measure brain activity. Their technology often involves the use of lightweight and affordable headsets or sensors that can detect brainwave patterns and convert them into data that can be used for various applications, such as gaming, meditation, and cognitive training.
The Maurer–Cartan form is a fundamental concept in the theory of Lie groups and differential geometry, particularly in the study of Lie group representations and the geometry of principal bundles. Given a Lie group \( G \), the Maurer–Cartan form is a differential 1-form on the Lie group that captures information about the group structure in terms of its tangent space.
A "moving frame" can refer to different concepts depending on the context, including mathematics, physics, and engineering. Here are a few interpretations: 1. **Mathematics (Differential Geometry)**: In the context of differential geometry, a moving frame is often used to describe a set of vectors that vary along a curve or surface.
In music, a "key" refers to the tonal center around which a piece of music is organized. It is defined by a specific scale that serves as the foundation for melodies and harmonies within a composition. Each key is typically associated with a specific note (the tonic) and a set of pitches that can be used in the music. Keys are categorized as major or minor: 1. **Major Key**: Associated with a bright and happy sound.
Examples under vhdl.
Run all examples, which have assertions in them:
cd vhdl
./runFiles:
- Examples
- Basic
- vhdl/hello_world_tb.vhdl: hello world
- vhdl/min_tb.vhdl: min
- vhdl/assert_tb.vhdl: assert
- Lexer
- vhdl/comments_tb.vhdl: comments
- vhdl/case_insensitive_tb.vhdl: case insensitive
- vhdl/whitespace_tb.vhdl: whitespace
- vhdl/literals_tb.vhdl: literals
- Flow control
- vhdl/procedure_tb.vhdl: procedure
- vhdl/function_tb.vhdl: function
- vhdl/operators_tb.vhdl: operators
- Types
- vhdl/integer_types_tb.vhdl: integer types
- vhdl/array_tb.vhdl: array
- vhdl/record_tb.vhdl.bak: record. TODO fails with "GHDL Bug occurred" on GHDL 1.0.0
- vhdl/generic_tb.vhdl: generic
- vhdl/package_test_tb.vhdl: Packages
- vhdl/standard_package_tb.vhdl: standard package
- textio
* vhdl/write_tb.vhdl: write
* vhdl/read_tb.vhdl: read - vhdl/std_logic_tb.vhdl: std_logic
- vhdl/stop_delta_tb.vhdl:
--stop-delta
- Basic
- Applications
- Combinatoric
- vhdl/adder.vhdl: adder
- vhdl/sqrt8_tb.vhdl: sqrt8
- Sequential
- vhdl/clock_tb.vhdl: clock
- vhdl/counter.vhdl: counter
- Combinatoric
- Helpers
* vhdl/template_tb.vhdl: template
The leading no-royalties options as of 2020.
China has been a major RISC-V potential user in the late 2010s, since the country is trying to increase its semiconductor industry independence, especially given economic sanctions imposed by the USA.
E.g. a result of this, the RISC-V Foundation moved its legal headquarters to Switzerland in 2019 to try and overcome some of the sanctions.
Paging is implemented by the CPU hardware itself.
Paging could be implemented in software, but that would be too slow, because every single RAM memory access uses it!
Operating systems must setup and control paging by communicating to the CPU hardware. This is done mostly via:
- the CR3 register, which tells the CPU where the page table is in RAM memory
- writing the correct paging data structures to the RAM pointed to the CR3 register.Using RAM data structures is a common technique when lots of data must be transmitted to the CPU as it would cost too much to have such a large CPU register.The format of the configuration data structures is fixed by the hardware, but it is up to the OS to set up and manage those data structures on RAM correctly, and to tell the hardware where to find them (via
cr3).Then some heavy caching is done to ensure that the RAM access will be fast, in particular using the TLB.Another notable example of RAM data structure used by the CPU is the IDT which sets up interrupt handlers. - CR3 cannot be modified in ring 3. The OS runs in ring 0. See also:
- the page table structures are made invisible to the process using paging itself!
Processes can however make requests to the OS that cause the page tables to be modified, notably:
- stack size changes
brkandmmapcalls, see also: stackoverflow.com/questions/6988487/what-does-brk-system-call-do/31082353#31082353
The kernel then decides if the request will be granted or not in a controlled manner.
Natural pseudodistance is a concept used in mathematical biology and ecology, particularly in the study of population genetics and evolutionary theory. It is typically used to quantify the genetic differences or relationships between populations or individuals based on genetic data. In general, a pseudodistance is a metric that measures how "far apart" two entities are within a particular space or context, but it may not fulfill all the properties of a true distance metric (such as the triangle inequality).
FFFFF 000 points to its own physical address FFFFF 000. This kind of translation is called an "identity mapping", and can be very convenient for OS-level debugging.When TLB is filled up, older addresses are overwritten. Just like CPU cache, the replacement policy is a potentially complex operation, but a simple and reasonable heuristic is to remove the least recently used entry (LRU).
With LRU, starting from state:adding
valid linear physical
----- ------ --------
> 1 00003 00005
1 00007 00009
1 00009 00001
1 0000B 000030000D -> 0000A would give: valid linear physical
----- ------ --------
1 0000D 0000A
> 1 00007 00009
1 00009 00001
1 0000B 00003The Linux Kernel reserves two zones of virtual memory:
- one for kernel memory
- one for programs
The exact split is configured by
CONFIG_VMSPLIT_.... By default:- on 32-bit:
- on 64-bit: currently only 48-bits are actually used, split into two equally sized disjoint spaces. The Linux kernel just assigns:
- the bottom part to processes
00000000 00000000to008FFFFF FFFFFFFF - the top part to the kernel:
FFFF8000 00000000toFFFFFFFF FFFFFFFF, like this:------------------ FFFFFFFF Kernel ------------------ C0000000 (not addressable) ------------------ BFFFFFFF Process ------------------ 00000000
- the bottom part to processes
Kernel memory is also paged.
In previous versions, the paging was continuous, but with HIGHMEM this changed.
There is no clear physical memory split: stackoverflow.com/questions/30471742/physical-memory-userspace-kernel-split-on-linux-x86-64
We get the time-independent Schrödinger equation by substituting this into Equation "time-independent Schrödinger equation for a one dimensional particle":
Now, there are two ways to go about this.
The first is the stupid "here's a guess" + "hey this family of solutions forms a complete basis"! This is exactly how we solved the problem at Section "Solving partial differential equations with the Fourier series", except that now the complete basis are the Hermite functions.
The second is the much celebrated ladder operator method.
esolangs.org/wiki/Y86 mentions:
One specification at: web.cse.ohio-state.edu/~reeves.92/CSE2421sp13/PracticeProblemsY86.pdf
It basically replaces a bunch of discrete digital components with a single chip. So you don't have to wire things manually.
Particularly fundamental if you would be putting those chips up a thousand cell towers for signal processing, and ever felt the need to reprogram them! Resoldering would be fun, would it? So you just do a over the wire update of everything.
Vs a microcontroller: same reason why you would want to use discrete components: speed. Especially when you want to do a bunch of things in parallel fast.
One limitation is that it only handles digital electronics: electronics.stackexchange.com/questions/25525/are-there-any-analog-fpgas There are some analog analogs, but they are much more restricted due to signal loss, which is exactly what digital electronics is very good at mitigating.
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 3. Visual Studio Code extension installation.
Figure 4. Visual Studio Code extension tree navigation.
Figure 5. Web editor. You can also edit articles on the Web editor without installing anything locally.Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension.Video 4. OurBigBook Visual Studio Code extension editing and navigation demo. Source. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact