This article aims at explaining the mathematical sense of the Principal Component Analysis (PCA) in practice.
How to Set Up a Custom Domain and Get a Free SSL Certificate on Firebase
In my previous article, I showed you how to deploy your project to Firebase and use it for free. Now, let’s explore additional benefits of Firebase. In the upcoming article, I will show you how to set up a custom domain name for your project and utilize a free SSL certificate from Firebase.
Pixel image rotation
Brief problem formulation
The program accepts as input the absolute path to the image in the bmp extension and the path where you save the result of the work. Then, it rotates the image by 90 degrees counterclockwise. Afterwards, the program saves the new image.
The program is executed on C.
Blinking into Morse code
Explaining main algorithm.
For a while I’ve been thinking of writing a scientific article. I wanted it to have certain utility.
Morse code is binary: it takes only two values – either dot (short) or hyphen (long). I figured out that short (s) can stand for two-eye blinking whilst long (l) can indicate left-eye blinking. Another question emerged: how to understand when does one-symbol recording stop?
Empty space between two symbols can be presented by right-eye blinking – r. If I input singly symbol of short (dot) and long (hyphen), I will blink my right eye once to indicate the space between two symbols.
To separate independent words, one has to blink her right eye twice and get rr.
Hence, I have collected an ordered set of symbols – r, l, s, - that can be converted into a full-fledged text. Once I accomplish the transformation, I get an answer.
Multithreaded FTP client
Task: To provide automation for transfer of large number of files.
Source - computer with autotest codebase.
Receiver - gateway for industrial data processing.
Test receiver - second PC with installed vsftpd service.
Feature Engineering: Techniques and Best Practices for Data Scientists
The most important stage in the data science process is feature engineering, which entails turning raw data into useful features that might enhance the performance of machine learning models. It calls for creativity, data-driven thinking, and domain expertise. Data scientists can improve the prediction capability of their models and find hidden patterns in the data by choosing, combining, and inventing relevant features. Handling missing data, scaling features, encoding categorical variables, constructing interaction terms, and other procedures are examples of feature engineering techniques. The best practises involve investigating the data, testing and improving features iteratively, and applying domain knowledge to draw out important information. The accuracy and effectiveness of machine learning models are significantly influenced by effective feature engineering.
Exploring a possible implementation of non-blocking IO by writing a server on pure syscalls
How do people usually write a server if they don't really care about performance? A program starts, then starts accepting incoming connections from clients and starts a new thread for each client, which is engaged in servicing this client. If you use framework, like Spring or Flask or Poco there, then it does something like this inside itself - the only difference is the threads can be reused, that is, taken from a certain pool. It's all quite convenient, but not too effective (and Spring is bad). Most likely, your threads serving clients do not live long and most of the time they are waiting either to receive data from the client or to send it to the client - that is, they are waiting for some system calls to return. Creating an OS thread is quite an expensive operation, as is context switching between OS threads. If you want to be able to serve a lot of customers efficiently, you need to come up with something else. For example, callbacks, but they are pretty inconvenient (though there are different opinions on this).
Another option is to use non-blocking I/O in combination with some kind of implementation of user-space threads (fibers). In this article I will show you how to write all this with your own hands.
Setting Up an Experiment Environment for Data-Driven Product Development
As a product owner, it is common to face the question of whether to proceed with option A or option B. Or, which version of the screen should be implemented to achieve better results? Making such decisions can be challenging, especially when you are under tight deadlines with limited resources. Furthermore, such decisions are made based on personal judgment or copying the approach of a competitor, which can lead to suboptimal results.
The good news is that one can avoid such pitfalls by setting up a simple experiment environment that requires relatively low effort. In this article, we will describe how you can achieve this.
Q1 2023 DDoS Attacks and BGP Incidents
Let's take a deeper look at the Q1 2023 DDoS attacks mitigation statistics and observations from Qrator Labs' perspective.
Google SSO for Kibana straightforward way on basic license
As many times before, I keep writing cheat sheets after the tasks which made me search a lot and glue things together before I found a solution. Long story short, this time I was asked to set up Google SSO for Kibana without switching from a basic license to a paid one. Kibana, by the moment, already had authentication set up and the customer wanted to log in there with the use of Google Workspace user accounts. Along with that, the customer wanted to keep user account which was already there, in Kibana. There was no need for role mapping or other advanced features, just plain SSO and that's all. As you probably know Elastic provides SSO feature only on paid license, so I have had no other way to get it working except for using 3rd party software. But first things first, let's list the steps we should go over:
GNU radio 802.11 black box optimization
In this post I'll share my experience in adjustment of WiFi physical channel. The channel was implemented on a software defined radio (SDR) platform. WiFi looks like a very complicated thing standardized over hundreds of pages. Could a non-expert with a PC and a couple of 100$ devices (HackRFs) somehow improve it? Here I try to develop a WiFi optimization approach basically agnostic of protocol implementation details. There's some math and Python programming in it.
About «free» #iam, #oidc, #saml, #etc
There is a task to develop a solution that allows:
- Access control to web applications via #oidc/#saml
- Access control to vanilla #Kubernetes
- SSH access control to bare-metal hosts - using SSH certificate technology if possible
- Authorizing users to other server applications such as #Vault, #PostgreSQL, #Kafka, #ClickHouse, #MongoDB
- Being able to connect users from third-party organizations to certain resources based on group membership, etc
- Ensuring that everything described above works, including the bare metal environment
Journey to find a headset with a good side talk cancellation mic for calls in an open office
TL;DR: All AI-based noise cancellations suck, only the physical cancellation technique works! And physical cancellation is implemented well only in Jabra devices yet, but other features suck them! All Bluetooth headsets suck too! So, no solution yet, just complaints!
The environment: I work in a pretty talky office room, where sit around 10 people, and all of them have many online conferences every day, including me. So, silence in the room is a rare situation.
The problem: The main problem is that most of the microphones pick up all side talk pretty loud, which makes it very unpleasant for other people to listen to my voice in meetings!
What is Information Technologies? Hard to gets in? Choosing a direction/profession and your first programming language
People-professionals are working in IT, not robots
In fact the average competition for one workplace in IT is about 500 people – the market lacks specialists! You can find and read more. It's not hard to find on the internet
Need specialists who know their business!
For this reason, I wrote about how to become one and what you should pay attention to at the beginning of your journey. Even have my presentation with IT-directions! Also I understand something in Game Development..
Flew!🐌
Elasticsearch as NoSQL Database
In this article, I will introduce NoSQL concepts and show how they are related to Elasticsearch, and we will consider this search engine as a NoSQL document store.
Q4 2022 DDoS Attacks and BGP Incidents
Now that 2022 has come to an end, we would like to share the DDoS attack mitigation and BGP incident statistics for the fourth quarter of the year, which overall saw unprecedented levels of DDoS attack activity across all business sectors.
In 2022, DDoS attacks increased by 73.09% compared to 2021.
Let's take a closer look at the Q4 2022 data.
Data Phoenix Digest — ISSUE 2.2023
Video recording of our webinar about dstack and reproducible ML workflows, AVL binary tree operations, Ultralytics YOLOv8, training XGBoost, productionize ML models, introduction to forecasting ensembles, domain expansion of image generators, Muse, X-Decoder, Box2Mask, RoDynRF, AgileAvatar and more.
BGP Route Leak prevention and detection with the help of the RFC9234
All the credit is due to the RFC’s authors: A. Azimov (Qrator Labs & Yandex), E. Bogomazov (Qrator Labs), R. Bush (IIJ & Arrcus), K. Patel (Arrcus), K. Sriram.
A BGP route leak is an unintentional propagation of BGP prefixes beyond the intended scope that could result in a redirection of traffic through an unintended path that may enable eavesdropping or traffic analysis, and may or may not result in an overload or complete drop (black hole) of the traffic. Route leaks can be accidental or malicious but most often arise from accidental misconfigurations.
Make first deb-src package by example cri-o
Overview
Once every true-linux engineer gets a trouble: there is no any software in his distro or it's built without needed options. I am keen on the phrase: "Only source control gives you freedom".
Of course, you can build this software on your computer without any src-packages, directly (with simplification: configure, make, make install). But it's a non-reproducible solution, also hard for distribution.
The better way is to make distro-aligned package that can be built if needed and that produces lightly distributed binary-packages. It's about debian-source packages(debian,ubuntu,etc), pkgbuild (for arch), ebuild for gentoo, src-rpm for red hat-based, and many others.
I will use cri-o like a specimen.
Before reading the text below I strongly recommend to get familiarized with the official Debian policy manual placed here and debhelper manpage.
Also you will be required to setup some variables like DEBMAIL and DEBFULLNAME for proper data in changelog and other places.
Top 10 IPTV Services for FireStick, Android TV, PC [Best 2023 Reviews]
Are you looking for the best IPTV services for FireStick, Android TV, and PC now?
The rising demand for IPTV services has also raised the number of service providers in the marketplace. IPTV has emerged as one of the leading entertainment sources these days. It offers an extreme level of comfort and convenience to the users and makes it easier for them to find their preferred content at affordable pricing.
IPTV is a more excellent and cost-effective solution for streaming cable channels conveniently. Using IPTV services is an altogether simple and easy-to-go process. You need to buy the preferable IPTV subscription and download the app on the supported devices. Most IPTV providers available in the marketplace need to provide high-end resolutions effortlessly.
IPTV serves as the primary source of Live TV Streaming and offers VOD movies and shows to the users. Please stay connected with us to know the leading IPTV services in detail.
The longer the format war goes on, the more opportunity smart players in the cable and IPTV and online spaces have to build market share.—Laura Behrens