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The On-Line Encyclopedia of Integer Sequences today

Mathematics *Social networks and communities

You can encounter integer sequences all around combinatorics, number theory, and recreational mathematics. And if there is a multitude of objects of the similar form, then one can create an index for these objects. The On-Line Encyclopedia of Integer Sequences, OEIS, is such an index.

This is a translation of my article The On-Line Encyclopedia of Integer Sequences in 2021, published in Mat. Pros. Ser. 3 28, 199–212 (2021).

This article covers the On-Line Encyclopedia inclusion criteria, its editorial process, its role in mathematics, and its future.

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How Can I Start My Own IPTV Provider?

IPTV *Monitors and TV

IPTV is quickly rising to the top of the list of TV viewing options for viewers worldwide. other types of home entertainment, including music and video. This indicates a developing market for service providers and a potential new source of income. But how can you set up an IPTV service? Mware Solutions can assist you in establishing the required infrastructure for a successful entry into this cutthroat market.

TV delivered using an Internet Protocol Network is known as IPTV. This new technology has the potential to alter how we watch television at home, get training, utilize computers, and even use cell phones. From computer monitors and mobile phone screens to plasma and LCD televisions, it is used to provide television services to all of these devices. But how can you launch an IPTV company and become a provider of IPTV? An IPTV business solution is what?

We, therefore, decided to offer an eight-week boot camp to teach you everything you require to launch your own IPTV company. You may build the necessary infrastructure with the aid of Setplex to successfully enter this cutthroat market.

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Total votes 3: ↑3 and ↓0 +3
Views 895
Comments 0

Digital modeling of analog guitar distortion effects

Circuit design *Manufacture and development of electronics *Software DIY Sound

The sound of rock music, in particular of hard rock and heavy metal, is largely based on a specially distorted guitar sound, for which electronic “distortion” devices, tube amplifiers in “overloaded” mode, computers with appropriate software and digital processors are used. increasingly using neural network algorithms.

The distorted sound of electric guitars began to gain popularity around the 1960s. Since that time, the sound of overloaded tube amplifiers, connected to powerful dedicated guitar speakers with large dedicated speakers, has been considered the benchmark in rock music. But tube amplifiers were relatively expensive and inconvenient to operate. Therefore, semiconductor distortion devices were developed.

At that time, the electrical circuitry of distortion devices was relatively simple and the signal output from their output only vaguely resembled the sound of an overloaded tube amplifier. Nevertheless, it was still somewhat similar to the “sound of a lamp” and this provided a powerful incentive for designers of analog semiconductor distortion circuits to continue their research, complicate circuits and propose new circuit solutions. The heyday of analog solid-state distortion was around 1995-2010. The most popular were electrical circuit diagrams like those shown in the figure below.

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Total votes 3: ↑3 and ↓0 +3
Views 468
Comments 0

I trained a neural network on my drawings and give the model for free (and teach you to create your own)

Python *Image processing *Machine learning *Graphic design *Artificial Intelligence
Tutorial

Great for seamless patterns, abstract drawings, and watercolor-styled images. How to use it and train a neural network on your own pictures?

Download the model here: https://huggingface.co/netsvetaev/netsvetaev-free

I wanna know!
Total votes 6: ↑6 and ↓0 +6
Views 925
Comments 0

«Look what I have!» — how we made the feature of screen sharing in the mobile video conferencing app

Development of mobile applications *Mobile applications design *Mobile App Analytics *Video conferencing
Sandbox

How we listened to the needs of our customers and implemented the feature with the maximum capabilities of the iOS and Android platforms. Then we looked into analytics, added onboarding, and usage grew. At the end of the article there are some cool conclusions and insights. Developing a video conferencing mobile app is fun!

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Total votes 4: ↑4 and ↓0 +4
Views 669
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Methodology for calculating results of a task set: taking into account its level of difficulty

IT Infrastructure *Mathematics *Statistics in IT IT-companies

In the world of academic knowledge evaluation, objective calculation of large data presents a serious problem. Can a student studying in an Advanced Maths class and getting B-marks be evaluated equally with another student, getting B-marks in a General Maths class? Can we create a system that would take into account the level of difficulty those students face?

This article will describe a system of independent evaluation we have been using for school olympics in five subjects (Mathematics, English Language, Russian Language, Tatar Language, Social Science) for students grades 1 to 11. In each academic year we organise six qualification tournaments, with about 15,000 students from different regions of Russia. Then we select the top ten participants in each subject and each grade for their future participation in the final (seventh) tournament, where only the best of the best are chosen. It means that 550 participants compete in the final tournament, which is about 5.5% of all participants in the academic year. 

It is obvious that those multiple tournaments cannot be absolutely homogenous, and inevitably the levels of difficulty for each set of tasks vary. Therefore, it is critical for us to take into consideration those variations of difficulty and calculate the results in the most objective manner.

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Quantum Computers Without Math and Philosophy

Quantum technologies

In this article, I will break down all the secrets of quantum computers piece by piece: what superposition (useless) and entanglement (interesting effect) are, whether they can replace classical computers (no) and whether they can crack RSA (no). At the same time, I will not mention the wave function and annoying Bob and Alice that you might have seen in other articles about quantum machines.

The first and most important thing to know is that quantum computers have nothing to do with conventional ones. Quantum computers are analog in nature, they have no binary operations. You have probably already heard about Qubits that they have a state of 0, 1 and 0-1 at the same time and with the help of this feature calculations are very fast: this is a delusion. A qubit is a magnet (usually an atom or an electron) suspended in space, and it can rotate on all three axes. In fact, the rotations of a magnet in space are the operations of a quantum computer. Why can it speed up calculations? It was very difficult to find the answer, but the most patient readers will find it at the end of the article.

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Total votes 8: ↑6 and ↓2 +4
Views 805
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How Yandex Made Their Biggest Improvement in the Search Engine with the Help of Toloka

Search engines *Data Mining *Machine learning *Artificial Intelligence Data Engineering *
Tutorial

Toloka is a crowdsourcing platform and microtasking project launched by Yandex to quickly markup large amounts of data. But how can such a simple concept play a crucial role in improving the work of neural networks?

Learn how
Total votes 1: ↑1 and ↓0 +1
Views 1K
Comments 0

Turning a typewriter into a Linux terminal

Abnormal programming *Circuit design *Developing for Arduino *Development for Raspberry Pi *Old hardware
Sandbox

Hi everyone, a few months ago I got a Brother AX-25, and since then, I've been working on turning it into a computer. It uses an Arduino to scan the custom mechanical keyboard and control the typewriter, and a Raspberry Pi is connected to the Arduino over serial so I can log into it in headless mode.

See how it works
Total votes 10: ↑10 and ↓0 +10
Views 1.3K
Comments 4

Let’s Discuss the Lorentz Transforms – Part the Last: The Real Derivation, or The Nail in the Casket

Mathematics *Physics

In this post there are a lot of references to the previous one – it is essential that you read it before getting down to this.

In my previous posts (see the list below below) I tried to express my doubts whether there is a real physical substrate to the Lorentz transforms. The assumptions about the constancy of the speed of light, the homogeneity of space-time, and the principle of relativity do not and cannot lead to the deduction of the Lorentz transforms – Einstein himself, for one, gets quite different transforms, and from those he goes over directly to the Lorentz transforms obviously missing a logical link (see Einstein p. 7, and also Part 1 of this discussion). As for the light-like interval being equal to zero, we saw that it can be attached to such assumptions only in error and cannot in itself be a foundation of a theory. I have to conclude that all that fine, intricately latticed construction of scientifictitious, physics-like arguments with the air of being profound is nothing but a smokescreen creating the appearance of a physical foundation while there is none.

What is then the real foundation of the Lorentz transforms? Let’s start from the rear end, the Minkowski mathematics. Historically, this appeared later than special relativity as a non-contradictory model of the Lorentz mathematical world; previously mentioned Varićak was among those who took part in its creation. Notwithstanding its coming later in history, it can be used as the starting point for derivation of the Lorentz transforms.

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Total votes 3: ↑3 and ↓0 +3
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Let’s Discuss the Lorentz Transforms – Intermission: Rapidity, and What it Means

Mathematics *Physics

I thought my previous post rather funny, and was surprised seeing it initially receive so few views. I thought the entertainment flopped, but fortunately I was wrong. I therefore feel it my duty before my readers to address the subject of the Landau & Lifschitz proof of the invariance of the interval.

You can find the summary of it in Wikipedia. Making their starting point the light-like interval always being equal to zero, Landau & Lifschitz seem to make a great fuss about it. The Wikipedia article even says: ‘This is the immediate mathematical consequence of the invariance of the speed of light.’ No, it is not.

I beg everyone’s pardon, but the light-like interval always being equal to zero is nothing else but the following statement: ‘The length of a ray of light will always be equal to the length of this ray of light’. Sounds like a cool story, bros and sis, but I cannot see what further inferences can be drawn from it. The ‘proof’ of this truism cannot fail under any circumstances whatever – whether you keep the speed of light invariant, or keep or change the metric of space or time or both – or make both metric and speed of light change – the light-like interval will remain equal to zero. I am okay with anyone wanting to prove it if they feel like it, but you cannot make it an ‘immediate mathematical consequence of the invariance of the speed of light’. Neither is it possible to make the constancy of the speed of light a consequence of the invariance of the light-like interval for the reason already mentioned: this is a truism. It does not prove anything, nor can it be a consequence of anything. When Landau & Lifschitz insist that this is a consequence of the constancy of the speed of light, that is either an error or a downright subterfuge, a means employed to create a spectre of logical connection between two unconnected notions, and charge this ghostly connection with pretended significance. And, since the following proof of invariance of an arbitrary interval hangs on the invariance of the light-like interval, we can altogether dismiss it: the necessity of introduction of such a measure as interval cannot be derived from the statement that a length of something will be equal to itself in whatever frame of reference it is measured.

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Total votes 3: ↑3 and ↓0 +3
Views 393
Comments 2

Let’s Discuss the Lorentz Transforms – Part 1: Einstein’s 1905 Derivation

Mathematics *Physics

Even as I am posting this, I can see that my previous post received a hundred and twenty plus views, but no comments yet. I am saying again that my pursuit is not to give an answer, but to ask a question. I only wonder if there is in fact no answer to the questions I am asking – but anyway, I will continue asking them. If you know how to deal with the problems I am setting – or happen to understand they are not problems at all, I will be most grateful for a constructive input in the comments section. I am sorry to say I was unable to make this post sound as light and unpretentious as the previous one. This one deals with harder questions, is a little wordy, and requires at least elementary knowledge of calculus to be read properly.

In my previous post we discussed the ‘Galilean’ velocity composition used for introduction or substantiation of relative simultaneity. It is not the only point where Einstein resorts to sums c + v or c – v: he does that actually to deduce the Lorentz transforms, notwithstanding the fact that a corollary of the Lorentz transforms is a different velocity composition which makes the above sums null and void. It looks like the conclusions of this deduction negate its premises – but this is not the only strange thing about Einstein’s deduction of the Lorentz transforms undertaken by him in his famous 1905 article.

In Paragraph 3 of that paper Einstein is considering the linear function τ (the time of the reference frame in motion) of the four variables x′ = x – vt, y, z, and t (the three spatial coordinates and time of the frame of reference at rest) and eventually derives a relation between the coefficients of this linear function.

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Total votes 3: ↑3 and ↓0 +3
Views 597
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Let’s Discuss Relativity of Simultaneity

Mathematics *Physics
Sandbox

There is one only too obvious problem with relativity of simultaneity in the way it is normally introduced, and I have never found an answer to it – what’s more, I never read or heard anyone formulate it. I will be grateful for an enlightening discussion.

The framework of the thought experiment introducing relativity of simultaneity is this. Two rays of light travel in opposite directions and reach their destination simultaneously in one frame of reference and at different moments in the other.

For example, in the Wikipedia article on the subject you can read:

‘A flash of light is given off at the center of the traincar just as the two observers pass each other. For the observer on board the train, the front and back of the traincar are at fixed distances from the light source and as such, according to this observer, the light will reach the front and back of the traincar at the same time.

‘For the observer standing on the platform, on the other hand, the rear of the traincar is moving (catching up) toward the point at which the flash was given off, and the front of the traincar is moving away from it. As the speed of light is finite and the same in all directions for all observers, the light headed for the back of the train will have less distance to cover than the light headed for the front. Thus, the flashes of light will strike the ends of the traincar at different times’.

I am always not a little surprised at the modesty displayed by the authors of such illustrations. If we grant the statement ‘the light headed for the back of the train will have less distance to cover than the light headed for the front’ to be true – how then do we evaluate the magnitude of the effect? Or, in other words, how much longer is one distance in comparison to the other?

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Total votes 3: ↑2 and ↓1 +1
Views 512
Comments 0

How in-app chats help e-learning platforms to be more interactive?

Instant Messaging *Development of mobile applications *API *Software Video conferencing

e-Learning is an extension of/ alternative to a traditional classroom setup. e-learning, commonly known as ‘online learning’ or ‘virtual learning’ is ideally a one-way or two-way digital communication established on a device with video and voice call integration using internet access. The last two years made us realize how technology can facilitate and improve communication. Digital technology had its impact in almost every industry including the sensitive education sector.

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It's alive

IT Standards *IT career Reading room The future is here IT-companies

I wonder why IT developer interviews are so strange most of the time. It feels as if the people are looking for computer science teachers, not engineers. All those theoretical questions that have no relation to the working reality. It is strange to be looking for eloquent teachers, who can perfectly explain any term or pattern, and then ask them to do the actual work. Maybe it is the imprint from the years spent in university when the teachers looked like all-knowing gods and seemed to solve any issue in your life. May be, may not. Anyway, these teachers stay in unis and don't do the work.

You know, what would be my universal answer to all interview questions? “I have no idea how and why it works, but I can use it, and I can use it for good”. This is the reality. Actually, no one knows exactly these hows and whys. What is a computer? What is electricity? What is an electron? No one knows for sure. But it works and we use it.

Imagine a famous author, like Stephen King, asked a question about the difference between deus ex machina and Mary Sue. Would his answer change the quality of his books? He may or he may not know all those scientific literature terms, but he can use the language and use it for good.

Every time I turn on my computer it is a wonder. I have no idea what is going on, but it awakes, it becomes alive, and I can communicate with it in its own sublime and subtle language.

Have you ever realised that all these electronic devices are monsters, Frankenstein's monsters? Some pieces of dead matter were put together, and then, with some electricity involved, it suddenly awoke. “It's alive!”. Had Frankenstein any idea why it turned alive? Of course not, or why he was so surprised? Every developer experiences this feeling almost every day. “It's working!”

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Total votes 7: ↑4 and ↓3 +1
Views 784
Comments 1