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Brainless Platform for a Robotic Vacuum Cleaner

Reading time11 min
Views1.3K
More on robotics.snowcron.com

First of all, this is just an exercise, useful as is, but the result is going to be far from an industrial level robots. Why doing it then?

For the same reasons we do all exercise: to get an experience. After all, when we write a character recognition «MNIST classifier» neural network, we know that the problem is solved long time ago. But we need to become familiar with tools and approaches. Same here.

Now, why is it called «brainless»?

Compensation for Error Caused by Limited Gain-Bandwidth of Operational Amplifiers in Low-pass Filters

Reading time6 min
Views4.7K
Amateur vs Pro

An operational amplifier has the internal compensation circuit for stability which limits its working bandwidth. Frequency response of the compensated Op Amp has slope of −6 dB/octave or −20 dB/decade. Unity gain frequency defines the bandwidth where the Op Amp is able to amplify a signal. If we multiply the gain and frequency at any point, the result is the same, allowing us to use this parameter to select the appropriate Op Amp. It is called Gain-Bandwidth Product, GBW or GBP. The limited open-loop gain introduces a closed-loop gain and phase error.

But we want to optimize our circuits, right?
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Laser that cuts inside the cornea: ReLEx procedure at the physical level

Reading time6 min
Views2K
The idea — to take and cut a lens in a transparent cornea — is not new. At first it was done manually, with a scalpel directly on the surface (difficult and very rough, with a sea of side effects). The first laser was used in 1979, then it was a pulsed infrared emitter with an effective pulse length of 4 nanoseconds.


Step 1: creating a plasma bubble, in fact — a microburst. Step 2: expansion of the shock and heat waves. Step 3: cavitation bubble (plasma expansion). Step 4: the formation of a parallel slice at the expense of several adjacent laser focus points.

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Using Data Science for house hunting in Montreal

Reading time7 min
Views4.9K

Introduction


I happen to live in Montreal, in my condo on the edge of McGill Ghetto. Close to Saint Laurent Boulevard or the Maine as locals call it, with all it's attractions — bars, restaurants, night clubs, drunken students. And once upon a time, on a particular lively night, listening to the sounds of McGill frosh students drunkenly heading home after hard night of studying. I thought, that it might be a good idea to move into my own house, a little bit further away from the action.


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Lab tour: Functional Materials and Devices of Optoelectronics at ITMO University

Reading time3 min
Views1.4K
Today we’re taking a look at the Functional Materials and Devices of Optoelectronics Lab at ITMO University, the equipment it houses, and the projects underway at the facility. It is an international research facility located in the center of St. Petersburg. The staff is primarily occupied with the search for innovative materials (semiconductors, metals, and nanostructured oxides), and the manufacturing of next-gen micro- and optoelectronic gadgets. Here we take a look at the high-tech equipment it utilizes.

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Bypassing LinkedIn Search Limit by Playing With API

Reading time7 min
Views17K
[Because my extension got a lot of attention from the foreign audience, I translated my original article into English].

Limit


Being a top-rated professional network, LinkedIn, unfortunately, for free accounts, has such a limitation as Commercial Use Limit (CUL). Most likely, you, same as me until recently, have never encountered and never heard about this thing.

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The point of the CUL is that when you search people outside your connections/network too often, your search results will be limited with only 3 profiles showing instead of 1000 (100 pages with 10 profiles per page by default). How ‘often’ is measured nobody knows, there are no precise metrics; the algorithm decides it based on your actions – how frequently you’ve been searching and how many connections you’ve been adding. The free CUL resets at midnight PST on the 1st of each calendar month, and you get your 1000 search results again, for who knows how long. Of course, Premium accounts have no such limit in place.

However, not so long ago, I’ve started messing around with LinkedIn search for some pet-project, and suddenly got stuck with this CUL. Obviously, I didn’t like it that much; after all, I haven’t been using the search for any commercial purposes. So, my first thought was to explore this limit and try to bypass it.

[Important clarification — all source materials in this article are presented solely for informational and educational purposes. The author doesn't encourage their use for commercial purposes.]
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Important Things to Know About Tensorflow 2.0

Reading time5 min
Views3.1K


Deep Learning applications have changed a lot of things. Some which give hope for a brighter future, and some which raise suspicions. However, for developers, the growth of deep learning applications has made them more perplexed about choosing the best among so many deep learning frameworks out there.

TensorFlow is one of the deep learning frameworks that comes in mind. It is arguably the most popular deep learning framework out there. Nothing justifies the statement better than the fact that Tensorflow is used by the likes of Uber, Nvidia, Gmail among other big corporations for developing state-of-the-art deep learning applications.

But right now, I am on a quest to find whether it indeed is the best deep learning framework. Or perhaps find what makes it the best out of all other frameworks it competes against.
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TOP-23 Language Learning Apps

Reading time6 min
Views6.1K
There are hundreds of language learning apps and hundreds of reviews and comparisons. Actually most of the comparisons are about the same programs. Are the apps really helpful or this is only ad and marketing? Yes, and Yes.

I have been studying English using various methods and resources over five years. Language learning is not my greatest talent but I have achieved B2 level (from A2) using only my smartphone and PC. I found a set of features that really helps you study a foreign language. Some of them are crucial, others are just useful. Under the cut you will find a rating of the language learning apps that I composed by analyzing these features, As Objective As Possible.
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A Brief History of Video Conferencing: From the Beginning to Full Commercial Use

Reading time11 min
Views9.6K
A Brief History of Video Conferencing

Video conferencing systems, so familiar to us today, have come a long way — more than a hundred years passed from fantastic ideas inspired by belief in unstoppable technical progress to the first mass implementation of video conferencing systems. A lot of dramatic events have come along the way. The way to success wasn’t easy at all.

Enhancing Magento Front-end Performance With ReactJS

Reading time9 min
Views5K

Magento


Magento is an open-source PHP based platform for building e-commerce solutions. Built by the Magento company (now part of Adobe), it is used by over 350,000 developers all over the world. It enables the creation of highly customizable digital storefronts for Business-to-Customer and Business-to-Business purposes. Magento 2, the transformed version of the Magento E-commerce Platform, comes with brand new architecture, coding structure, and database design.

a) General overview

Magento’s platform is built upon PHP and MySQL. During its lifetime of 10 years (the version 1.0 released in March 2008 and the version 2.0 in November 2015, it has undergone changes in terms of structure and development patterns and is now in its second major version, Magento 2.

Magento’s structure is comprised of two main parts, one being the back-end, with the database and MySQL, and Model, Data and Service interfaces, as can be seen in figure 3. These are directly connected and used in Magento’s Blocks, Layouts, and Templates, which would be defined as the front-end of the application.
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Winning PHDays 9 The Standoff: The chronicle by the True0xA3 team

Reading time16 min
Views1.8K
This is an English-language summary of two absolutely outstanding articles written by Vitaliy Malkin from «Informzashita» whose team, True0xA3, became the winners of the prestigious black hat competition The Standoff during Positive Hack Days 9 in May of 2019.

Vitaliy has published three detailed articles on Habr, two of which were dedicated to the description of the strategies that True0xA3 team used before and during the competition to secure this team the title of the winners. I felt that the only thing that those two articles were lacking was a summary in English so that a wider audience of readers could enjoy them. So, below is the summary of two articles by Vitaliy Malkin, together with images Vitaliy published to clarify his points. Vitaliy has OKed me doing the translation and publishing it.
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Launching a taxi-hailing app in Tokyo: How Sony does it with S.Ride?

Reading time2 min
Views1.4K
image

Uber, as we know, operates only in 650 cities and remains the best among all taxi apps. But have you ever imagined about other cities and their demand for taxi applications? If you did, you would have certainly come across a few regional apps like Ola, Didi Chuxing, Japan Taxi, etc. These apps are focused on fulfilling the demands of locals; and in that way, they have succeeded and generated revenue tremendously. If you search for the reason behind the success of these apps, it inevitably ends up in the kind of service it provides its customers. So, it all depends on how well you bestow your service (whether you focus regionally or globally).
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The History of SXSW: How It All Started

Reading time5 min
Views1.7K
SXSW is a festival of culture and technology held every spring in Austin, Texas. It’s a global phenomenon, with hundreds of thousands attending the event every year and millions more following the media coverage. Even if you’ve never heard of it, you’ve certainly felt its influence on our culture.

But it wasn’t always that way.

«Where, where have you gone», or searching for missing stations on public transport routes in OpenStreetMap

Level of difficultyMedium
Reading time6 min
Views1.1K

OpenStreetMap (OSM) is a global project formed around a geographic information database which is being filled by all comers — both enthusiasts and interested companies. Anybody can contribute, but the openness has its downside: incorrect edits often get into the database. Hence plenty of validators of OSM data have been written which allow to maintain the data quality at an acceptable level.

Since 2016 there exists an open source subway preprocessor that validates (generates error reports) rapid transit routes in OSM for completeness and logical/topological errors, and converts them into formats that are suitable for routing and rendering, e.g. GTFS. Besides OSM data it takes a list of public transport (PT) networks which contains the checking information about the number of lines, stations etc. per a PT network. The preprocessor has successfully proven itself in the preparation of PT data for applications such as Maps.me and Organic Maps.

In this article, I would like to share an approach to detecting one of the types of errors that occur quite often in OSM data and automatic detection of which is somewhat challenging. It's an accidental loss of a station from a route. The source code of the validator and the described algorithm are open source. But first, let's define the concepts used to represent PT data in OpenStreetMap.

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A new platform for FPGA seminars based on Gowin Tang Nano 9K: adding sound, graphics and microarchitecture labs

Reading time3 min
Views2.1K

Gowin has clear advantages over Xilinx in the educational FPGA board market: Gowin boards are several times less expensive, the synthesis speed is several times faster, and the EDA package is two orders of magnitude smaller: we are talking about 1G versus 100G disk space. Of course, Xilinx is still the king of high-end prototyping boards that cost $10K-100K, but for the students such boards are irrelevant; such boards are for ASIC design companies. A beginning EE student needs a board for less than $100, and Gowin not only fits the bill but also covers all the needs, specifically:

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What is to see under the Black Sun of Giedi Prime?

Level of difficultyEasy
Reading time6 min
Views2.3K

The director Denis Villeneuve and cinematographer Greig Fraser in their Dune: Part Two movie made a curious decision to film the scenes on the surface of the Giedi Prime planet in the infrared spectrum. It turned out to have interesting aesthetics and there are some interesting related physics to discuss and speculate about how realistic the look of it is.

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The Collatz conjecture is the greatest math trick of all time

Reading time4 min
Views3.7K

On the Internet and in non-fiction literature you can often find various mathematical tricks. The Collatz conjecture leaves all such tricks behind. At first glance, it may seem like some kind of a trick with a catch. However, there is no catch. You think of a number and repeat one of two arithmetic operations for it several times. Surprisingly, the result of these actions will always be the same. Or, may be not always?

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The Dino game from Google Chrome using FPGA

Reading time4 min
Views4.5K

Many people are familiar with the situation when there is no Internet, and a small dinosaur appears on the Google Chrome screen. Today we will tell you how to implement this game on the Cyclone IV FPGA board.

We are Yegor Blinov, Egor Kuziakov, and Inga Ezhova - the first-year students of Innopolis University. In our program, there was a course "Computer Architecture", where we had labs with FPGA boards Cyclone IV and MAX10. We were inspired by this equipment and decided to implement the project on one of the boards.

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