The previous discussion done, we have surmounted the difficult waters and are now sailing into something much more pleasure-like and hopefully even entertaining.

As I promised, we will be discussing the invariance of the interval, that is to say, the following relation:

This question comes up for a lot of us as we trying to advance our career and reach new heights. At the moment when I was challenged by it, I came across a wonderful book by Edmond Lau "Effective Engineer".

As always going through the book, I write new thoughts down. And today I want to share the compilation of things that I have found useful from the book. This is by no means an ad for the book, but I think it has some really interesting approaches for us to explore together.

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.

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?

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.

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!”

The Positive Hack Days 11 forum, which took place May 18–19, 2022, was truly epic. The bitterly fought ATM hacking contest featured no fewer than 49 participants. How cool is that? The winner of this year's prize fund of 50,000 rubles, with the handle Igor, was the first to hack the virtual machines. And he wasn't even at the event! :)

Besides Igor, eight other participants picked up prizes this year for their VM-hacking skills. They were: drd0c, vient, vrazov, durcm, zxcvcxzas7, asg_krd, hundred303, and drink_more_water_dude. A big thank-you to everyone who took part, and for those who weren't at PHDays, here are the links to the virtual machines.

Recipe for improving your productivity

We're continuing to explore micro service architecture. In today's blog Alexander Solyar, Lead system architect at Innotech, describes the main challenges analysts are facing while working with micro services. He also shares a number of effective solutions and recommendations.

The National Internet Segment Reliability Research explains how the outage of a single Autonomous System might affect the connectivity of the impacted region with the rest of the world. Generally, the most critical AS in the region is the dominant ISP on the market, but not always.

As the number of alternate routes between ASes increases (the "Internet" stands for "interconnected networks" - and each network is an AS), so does the fault-tolerance and stability of the Internet across the globe. Although some paths are more important than others from the beginning, establishing as many alternate routes as possible is the only viable way to ensure an adequately robust network.

The global connectivity of any given AS, whether an international giant or a regional player, depends on the quantity and quality of its path to Tier-1 ISPs.

Usually, Tier-1 implies an international company offering global IP transit service over connections with other Tier-1 providers. Nevertheless, there is no guarantee that such connectivity will always be maintained. For many ISPs at all "tiers", losing connection to even one Tier-1 peer would likely render them unreachable from some parts of the world.

The title of the article is a question I was asked in an interview for a Middle position. In this article, we will look at Unity coroutines, what they are, and at the same time we will capture the topic of Enumerator \ Enumerable in C # and a little secret of foreach. The article should be very useful for beginners.

In this article, we will look at a way to give the user the ability to upload any files, such as textures. And let's touch on the topic of launching JS functions from C# within Unity. As a result, we will get a script that, by calling just one function, will open a window for selecting files.

First mentions of micro service architecture application go back to the previous decade. Today this approach became the industry standard. Alexander Solyar, Lead software architect at Innotech, dives into details, shares professional insights and practical rules for working with micro services .

The present invention relates to an analog signal capturing devices generally and monochrome or color image capture sensors, such as a scanner or a Charge-Coupled-Device (“CCD”) for video and photo camera in particular, which are almost free from moiré and aliasing. The present invention relates to methods for enhancing the resolution of an image capture device and device for digital color/grey image displaying also.

Thanks to yarbabin for the logo

Electronic payment systems have existed on the Internet for a long time, and some bugs in them are twenty years old. We've found critical vulnerabilities allowing us to steal money and drive up the balance. Today we will analyze typical implementations of payment processing and related security issues.

This tutorial will guide you step by step in building an Android chat app in Kotlin with the help of third-party messaging SDKs. The reason I chose Kotlin for this tutorial is that - it is a lightweight programming language suggested by Google for building apps that work on Android devices. 

In the steps ahead, I’ll show you how to develop an app in Android Studio, with messaging features that can integrate using SDKs. I use MirrorFly’s chat SDKs throughout this tutorial.

This technical note is devoted to covering information regarding all primary C++ programming language standards: C++03/98/11/14/17/20.

I am glad to share a technical note with some details regarding the C and all primary C++ programming language standards based on my experience and materials from the Reference Section of this document.

As of August 15, 2022, this technical note in PDF format consists of 72 pages.

Queries in PostgreSQL. Hashing

So far we have covered query execution stages, statistics, sequential and index scan, and have moved on to joins.

FL_PyTorch: Optimization Research Simulator for Federated Learning is publicly available on GitHub.

FL_PyTorch is a suite of open-source software written in python that builds on top of one of the most popular research Deep Learning (DL) frameworks PyTorch. We built FL_PyTorch as a research simulator for FL to enable fast development, prototyping, and experimenting with new and existing FL optimization algorithms. Our system supports abstractions that provide researchers with sufficient flexibility to experiment with existing and novel approaches to advance the state-of-the-art. The work is in proceedings of the 2nd International Workshop on Distributed Machine Learning DistributedML 2021. The paper, presentation, and appendix are available in DistributedML’21 Proceedings (https://dl.acm.org/doi/abs/10.1145/3488659.3493775).

The project is distributed in open source form under Apache License Version 2.0. Code Repository: https://github.com/burlachenkok/flpytorch.

To become familiar with that tool, I recommend the following sequence of steps:

Once the Teacher asked the Author:

Are there methods of redundancy introducing at an informational level, other than those that are studied by the theory of error-correcting codes? Emphasizing that he is talking about information redundancy, the Teacher thus made it clear that the question does not imply various ways of energy redundancy introducing, which are well studied in communication theory. After all, the noise immunity of information transmission is traditionally assessed by means of a threshold value that is calculated as the ratio of signal energy to noise energy. It is known that the methods of the theory of error-correcting codes offer an alternative solution, allowing energy saving.

After a cogitative pause, the Author answered in the affirmative, following intuition rather than rational knowledge. Upon hearing the answer, the Teacher noticed that this is a wrong conclusion and there are no such methods.

However, over time, the Author began to suspect that the immutability of the paradigm formulated above could be questioned.